Пайка металлов. Способы, материалы, припои, флюсы для пайки металлов

Использование пайки известно с древнейших времен. В гробнице вавилонской царицы (III тыс . лет до н. э.), в засыпанной пеплом Везувия Помпее (79 г. до н.э.), во время других раскопок в Египте, Риме и Греции — всюду археологи находили паяные металлические изделия. Припои древних римлян церарий и аргентарий по своему химическому составу близки к существующим в настоящее время ПОС-30 и ПОС-50.

В истории использования пайки можно выделить три периода, которые связаны с развитием источников нагрева и особенностями применяемой техники. Первый период начался в бронзовом веке, когда человечество начало изготавливать изделия из бронзы и источником нагрева служило твердое топливо. Второй период (конец XIX ст.) характеризуется началом применения для нагрева электрической энергии. Третий период начался в 1930–1940-х годах и связан с созданием техники из новых металлов и их сплавов — циркония, вольфрама, алюминиевых, титановых, высокопрочных и жаропрочных сталей и сплавов. Это привело во второй половине ХХ ст. к разработке принципиально новых способов пайки. В настоящее время технические возможности пайки значительно расширились. Во многих случаях пайка является единственно возможной технологией неразъемного соединения новых материалов.

Пайка — процесс получения неразъемного соединения металлов, находящихся в твердом состоянии, расплавленным припоем. Припоем является материал с температурой плавления ниже температуры плавления паяемых материалов. При пайке (в отличие от сварки) плавится только присадочный сплав — припой, а между паяемым материалом и припоем протекает процесс взаимного растворения компонентов.

Требования, предъявляемые к паяному соединению и характеризующие условия его эксплуатации, определяются служебными свойствами изделия в целом: механическими свойствами, герметичностью, вакуум-плотностью, электросопротивлением, коррозионной стойкостью, стойкостью против термоударов, перегрузок и др.

В процессе пайки расплавленный припой вводится в зазор между нагретыми соединяемыми деталями. Припой смачивает поверхности деталей, растекается и заполняет зазор между ними. Взаимодействие припоя с материалом сопровождается растворением основного металла в жидком припое с образованием эвтектик и твердых растворов, взаимной диффузией компонентов припоя в сторону основного металла и компонентов основного металла в сторону припоя с последующей кристаллизацией жидкой прослойки.

Формирование прочного и надежного соединения зависит от химического состава взаимодействующих металлов, температуры и продолжительности пайки, определяющих физико-химические и диффузионные процессы, протекающие между припоем и основным металлом. Чем выше температура процесса и его длительность, тем больше степень взаимной диффузии между расплавленным припоем и основным металлом и тем выше механическая прочность соединяемых деталей. Кроме того, прочность пайки зависит от величины зазора между паяемыми деталями. Так, при малых зазорах улучшается затекание припоя под действием капиллярных сил, вследствие чего значение временного сопротивления паяного соединения больше значения временного сопротивления самого припоя.

Припой прочно соединяется с поверхностью изделия только тогда, когда хорошо смачивает ее. Для этого поверхность должна быть тщательно очищена от загрязнений. Кроме этого, для удаления пленок оксидов с поверхностей паяемого материала и припоя и для предотвращения их образования при пайке используют паяльные флюсы. Флюсы, кроме того, способствуют лучшему затеканию припоя в зазор между соединяемыми деталями и растеканию по их поверхности. Некоторые припои, содержащие эффективные раскислители (бор, кремний, барий, щелочные металлы

иудтр.) мог ные пленки.

сами выполнять роль флюсов, переводя в шлак оксидКачество паяных соединений зависит от правильного выбора способа пайки, используемых основных и вспомогательных материалов, технологического процесса пайки.

Способы пайки. Современные способы пайки принято классифицировать по следующим признакам: механизмам удаления оксидной пленки с поверхности паяемого материала, видам процессов образования припоя в зазоре, условиям заполнения зазора припоем, температурным и временным режимами кристаллизации паяного шва, температуре пайки и используемым источникам нагрева, наличию или отсутствию давления на паяемые деталив, роедмнеонности и очередности выполнения паяных соединений (рис. 3.76).

По механизмам удаления оксидной пленки способы пайки делятся на флюсовые и бесфлюсовые.

Флюсовая пайка — пайка с применением флюса. При этом флюс может также участвовать в образовании самого припоя путем выделения компонентов, плавящихся при пайке.

Бесфлюсовая пайка — пайка без применения флюса, когда удаление оксидных пленок осуществляется в восстановительной или инертной газовой среде, вакууме, а также за счет применения ультразвука.

В первом случае удаление оксидов происходит при высоких температурах за счет их восстановления или самопроизвольного распада (диссоциации), а при ультразвуковой пайке их разрушение осуществляется за счет ультразвуковых колебаний, создаваемых в расплавленном припое, наносимом на соединяемый металл специальным паяльником.

По видам процессов образования припоя в зазоре способы пайки подразделяются на пайку готовым припоем, контактно-реактивную и реактивно-флюсовую.

Рис. 3.76. Классификация способов пайки

Пайка готовым припоем — способ пайки, при котором используется заранее приготовленный припой. В качестве припоя может использоваться металлический (полностью расплавляемый) или композиционный припой. В композиционном припое помимо металлической основы содержится тугоплавкий наполнитель (порошки, волокна, сетки), который сам не плавится, а при плавлении металла припоя образует разветвленную сеть капилляров, удерживающих под действием капиллярных сил его жидкую часть в зазоре между соединяемыми деталями.

Контактно-реактивная пайка — способ пайки, при котором жидкий припой образуется в результате межфазного взаимодействия и последующего контактного плавления соединяемых материалов или соединяемых материалов и прослойки промежуточного металла. К этому способу пайки относится сваркопайка. Сваркопайка — пайка разнородных материалов, при которой более легкоплавкий материал локально нагревается до температуры, превышающей температуру его плавления, и выполняет роль припоя.

Реактивно-флюсовая пайка — способ пайки, при котором припой образуется в результате химических реакций между основным металлом и флюсом. Например, при пайке алюминия с использованием флюса ZnCl₃ в результате химической реакции восстановления

3ZnCl₃ + 2Al ↔2AlCl₃ + 3Zn

образуется цинк, который служит припоем.

По условиям заполнения зазора припоем пайку можно разделить на капиллярную (ширина зазора

При капиллярной пайке припой заполняет зазор между соединяемыми поверхностями и удерживается в нем за счет капиллярных сил. Соединение образуется в результате растворения металла основы в жидком припое и последующей кристаллизации раствора. Некапиллярная пайка — способ пайки, при котором припой заполняет зазор под действием силы тяжести или прилагаемых извне сил (магнитных, электромагнитных и др.). К этому способу пайки относится пайкосварка. При пайкосварке форма кромок соединяемых заготовок подобна форме кромок при сварке плавлением. Соединение деталей осуществляется приемами, характерными для сварки, а в качестве присадочного металла используется припой,

который под действием силы тяжести заполняет зазор.

Способы пайки по температурным и временным режимам кристаллизации паяного шва подразделяются на пайку с кристаллизацией при охлаждении и кристаллизацией при выдержке (диффузионная).

Температурный режим пайки с кристаллизацией при охлаждении состоит из нагрева припоя до температуры на 50…100 °С выше

температуры его плавления и последующего охлаждения соединения. Этот способ из-за относительно быстрого охлаждения характеризуется отсутствием диффузии в объеме взаимодействующих металлов.

Пайка с кристаллизацией при выдержке (диффузионная пайка) — способ пайки с изотермической выдержкой, при которой образование соединения сопровождается взаимной диффузией припоя и паяемого материала. Для диффузионной пайки характерна продолжительная выдержка при температуре образования паяного шва, а после завершения процесса — при температуре ниже солидуса припоя. В результате диффузии в шве образуются твердые растворы, что обеспечивает более однородный состав паяного шва и позволяет повысить его прочность и пластичность.

В зависимости от температуры пайки различают низкои высокотемпературную пайку. При низкотемпературной пайке температура плавления припоя t_пл t_пл ≥ 450 ° С. Целесообразность такого деления обусловлена тем, что используемые основные и вспомогательные материалы существенно отличаются по своим свойствам в зависимости от температуры процесса.

Способы пайки в зависимости от используемых источников нагрева разделяют на пайку в печах, индукционную, погружением, газопламенную, плазменную и паяльниками.

При пайке в печах соединяемые заготовки нагревают в специальных печах: электросопротивления, с индукционным нагревом, газопламенных и газовых. Припой заранее закладывают в шов собранного узла, на место пайки наносят флюс и затем изделие помещают в печь, где его нагревают до температуры пайки. Этот способ обеспечивает равномерный нагрев соединяемых деталей без заметной их деформации.

При индукционной пайке паяемый участок нагревают в индукторе токами высокой частоты. Для предохранения от окисления изделие нагревают в вакууме или в защитной среде с применением флюсов.

Пайку погружением выполняют в ваннах с расплавленными солями или припоями. Соляная смесь обычно состоит из 55 % K Сl и 45 % НС1. Температура ванны — 700…800 °С. При пайке погружением в ванну с расплавленным припоем покрытые флюсом детали предварительно нагревают до температуры 550 ° С. Пайку погружением в расплавленный припой используют для соединения деталей из стальных, медных и алюминиевых сплавов.

При газопламенной пайке заготовки нагревают и припой расплавляют горелками для газовой сварки. В качестве горючих газов используют ацетилен, природные газы, водород, пары керосина и т. п.

При плазменной пайке плазмотроном, обеспечивающим более высокую температуру нагрева, паяют тугоплавкие металлы — вольфрам, тантал, молибден, ниобий и т. п.

При пайке паяльниками основной металл нагревают, а припой расплавляют за счет теплоты, аккумулированной в массе металла паяльника. Для низкотемпературной пайки применяют паяльники с периодическим и непрерывным нагревом и ультразвуковые. Паяльник с периодическим нагревом в процессе работы периодически подогревают посторонним источником теплоты. Для непрерывного нагрева используют электропаяльники. Паяльники с периодическим и непрерывным нагревом чаще используют для флюсовой пайки черных и цветных металлов легкоплавкими припоями с температурой плавления ниже 300…350 °С. Ультразвуковые паяльники применяют для бесфлюсовой пайки на воздухе и пайки алюминия. В этом случае оксидные пленки разрушаются за счет колебаний ультразвуковой частоты.

По наличию или отсутствию давления на паяемые детали способы пайки подразделяются на пайку без давления и пайку под давлением (прессовая пайка). Прессовая пайка используется в тех случаях, когда необходимо обеспечить четкую фиксацию взаимного положения деталей и требуемую величину зазора. Для сжатия деталей с требуемым усилием применяют специальные приспособления — механические зажимы. При высоких температурах этот способ нередко является единственно возможным.

По одновременности выполнения паяных соединений способы пайки делятся на одновременную пайку и ступенчатую. При одновременной пайке за один цикл нагрева в одном изделии (узле) выполняют несколько паяных соединений, а при ступенчатой — каждое последующее соединение выполняют после предыдущего.

Материалы, применяемые при пайке. Материалы, применяемые при пайке, делятся на основные и вспомогательные. К основным материалам относятся припои, а к вспомогательным — паяльные флюсы, восстановительные, инертные газовые среды и вакуум.

Классификация припоев осуществляется по многим признакам, основными из которых являются химический состав и температура плавления. Классификация по химическому составу осуществляется по основным химическим элементам, входящим в их состав (оловянно-свинцовые, оловянные, свинцовые, медно-цинковые, серебряные, медные, палладиевые и др.).

По температуре плавления все припои подразделяют на припои для низкотемпературной пайки (t_пл t_пл ≤ 145 °С) и легкоплавкие (145 ° С t_пл t_пл ≥ 450 °С): среднеплавкие (450 °С ≤ t_пл ≤ 1 100 °С), высокоплавкие (1 100 °С t_пл ≤ 1 850 °С) и тугоплавкие (t_пл ≥ 1 850 °С). Припои для низкотемпературной пайки используют в промышленности и в быту для пайки изделий, которые не подвергаются воздействию высоких температур и значительных механических нагрузок. Припои для высокотемпературной пайки применяют тогда, когда требуется высокая прочность и (или) работоспособность при больших температурах.

Припои для низкотемпературной пайки. К особо легкоплавким припоям с температурой плавления 45…145 °С относятся сплавы эвтектического состава, содержащие висмут, свинец, олово, кадмий. К таким сплавам относятся, например, сплавы Гутри (t_пл = 45 °С), Вуда (t_пл = 60,5 °С), Липовица (t_пл = 70 °С), Д’Арсенваля (t_пл = 79 °С), Розе (t_пл = 93,7 °С), Ньютона (t_пл = 96 °С), ПОСВ 33 ( t_пл = 130 °С), ПОСК 50-18 (t_пл = 145 °С).

Особолегкоплавкие припои находят применение, когда опасен перегрев не только паяемого материала, но и материала деталей изделия, не подвергаемых пайке. Такие припои широко применяются в электронике, электротехнике, в частности, при изготовлении приборов противопожарного назначения. Припой ПОСВ 33 применяется для пайки плавких сигнальных предохранителей, а ПОСК 50-18 — для деталей из меди и ее сплавов, не допускающих местного перегрева, в частности, полупроводниковых приборов.

Наиболее распространенными легкоплавкими припоями являются оловянно-свинцовые.

Маркировка оловянно-свинцовых припоев состоит из букв, обозначающих: П — припой, ОС — оловянно-свинцовый, Су — легированный сурьмой, и цифр, следующих после букв через дефис и обозначающих соответственно содержание олова и сурьмы. Буква М в марке припоя ПОС 61М обозначает легирующий элемент Cu

(1,2…2 %). Содержание свинца в марке не указывается и определяется по разности. Например, ПОССу 10-2: П — припой, ОС — оловянно-свинцовый, 10 % Sn, 2 % Sb, остальное — Pb.

Оловянно-свинцовые припои (ПОС 90, ПОС 61, ПОС 40, ПОС 18, ПОС 10 и др.) обладают высокими технологическими свойствами и весьма пластичны. Пайку этими припоями проводят обычно при нагреве паяльником. Минимальную температуру плавления (t_пл = 190 °C) и лучшие технологические свойства имеет припой ПОС 61. Его состав близок к эвтектическому в системе «олово – свинец». Наиболее тугоплавким является припой ПОС 10 (t_пл = 299 °C). Такие оловянно-свинцовые припои применяются для пайки электрои радиоаппаратуры (контактные поверхности электрических аппаратов, приборов, реле), точных приборов с высокогерметичными швами, где недопустим перегрев.

Для повышения прочности в оловянно-свинцовые припои вводят сурьму (ПОССу 61-0,5, ПОССу 25-0,5, ПОССу 9-2, ПОССу 10-2,

ПОССу 4-4, ПОССу 4-6 и др.). Малосурьмянистые припои, содержащие 0,2…0,5 % Sb и обладающие повышенной пластичностью, обеспечивают получение герметичных швов и применяются для пайки оцинкованных и цинковых деталей. Такие припои применяются для пайки электроаппаратуры, обмоток электрических машин, оцинкованных радиодеталей при жестких требованиях к температуре, свинцовых кабельных оболочек электротехнических изделий неответственного назначения, радиаторов, теплообменников и др. Сурьмянистые припои, содержащие 2…6 % Sb, широко используются в различных отраслях техники, требующих повышенной прочности паяных соединений. Такие припои применяются для пайки холодильных устройств, деталей автомобилестроения, деталей с клепаными швами из латуни и меди и др.

Для уменьшения склонности меди к химической эрозии при пайке используют оловянно-свинцовый припой ПОС 61М, легированный медью в количестве (1,2…2 %), близком к его предельной растворимости при температуре пайки, но не ухудшающим технологических и специальных свойств припоя и паяных соединений. Припой ПОС 61М применяется для пайки тонких (толщиной менее 0,2 мм) медных проволок, фольги, проводников в кабельной, электрои радиоэлектронной промышленности.

К легкоплавким припоям также относятся серебряные припои

(ПСрО 10-90, ПСрОСу 8, ПСрМО 5, ПСрОС 3,5-95, ПСр 3,

ПСр 3Кд, ПСр 2 и др.), содержащие серебро в незначительных количествах (1…10 %), а также олово, свинец или кадмий. В качестве легирующих элементов легкоплавких серебряных припоев выступают сурьма, медь или цинк. Максимальная температура плавления этих припоев составляет от 183 до 342 °С.

Легкоплавкие серебряные припои применяются для пайки меди, никеля и медных и медно-никелевых сплавов с посеребренной керамикой, проводов, работающих во всех климатических условиях без защиты соединений лакокрасочными покрытиями, стальных и серебряных изделий.

Припои для высокотемпературной пайки. Припои для высокотемпературной пайки обеспечивают более прочные соединения, чем припои для низкотемпературной, т. к. вследствие высокой температуры нагрева более интенсивно происходит взаимная диффузия элементов основного металла и припоя. Однако переходное электросопротивление таких припоев ниже, чем низкотемпературных.

К среднеплавким припоям с температурой до 1 100 °С относятся серебряные и меднок-цоивные припои.

К среднеплавким серебряным припоям относятся припои, в состав которых помимо серебра (10…70 %) в значительных количествах входят медь (ПСр 72, ПСр 50 и др.) или медь и цинк (ПСр 70, ПСр 45 и др.). Широкое применение находит припой ПСр 72, имеющий эвтектический состав с очень хорошими технологическими свойствами. Припои ПСр 45, ПСр 50, ПСр 70, ПСр 72 отличаются высокой пластичностью и технологичны. Такие припои применяются для пайки меди, медных и медно-никелевых сплавов, никеля, ковара, нейзильбера, латуней и бронз, а также железоникелевых сплавов с посеребренными деталями из стали, титана и титановых сплавов с нержавеющей сталью и т. п.

Некоторые припои, помимо этих элементов, содержатикйадм (ПСрКдМ 50-34-16 и др.), олово (ПСр 62 и др.), марганец (ПСр 37,5), фосфор (ПСр 25Ф) и др. Припои с кадмием применяются для пайки цветных металлов и стали, с марганцем — меди и медных сплавов с жаропрочными сплавами и нержавеющими сталями, с фосфором (самофлюсующиеся припои) — меди с бронзой,

меди с медью, бонрозонйзы с бр

и т. п.

Медно-цинковые припои (ПМЦ 36, ПМЦ 48, ПМЦ 54) используются для пайки меди, медных сплавов и сталей. Маркировка медно-цинковых припоев состоит из букв: П — припой, МЦ — медно-цинковый, и цифр, показывающих процентное содержание меди, остальное — цинк.

К высокоплавким припоям с температурой плавления более

1 100 °С относятся припои на основе меди и палладия.

Чистая раскисленная медь М0, M1 весьма широко применяется для пайки углеродистых и легированных сталей, никеля и его сплавов. Она хорошо смачивает сталь и растекается по ней, имеет более высокую прочность, чем среднеплавкие припои, высокую пластичность и менее дефицитна, чем серебро. Температура пайки медью находится в интервале 1 100…1 200 °С.

Особенности взаимодействия меди с другими элементами позволяют создавать припои на ее основе с широким диапазоном температур пайки (700…1 200 ° С). Например, легирование меди палладием и никелем вызывает непрерывное повышение температуры плавления медного припоя.

Для пайки деталей, работающих при высоких температурах, особенно подвергающихся трению (вентили и т. п.), используют медные припои, содержащие 2,5…10 % Fe, с температурой ликвидуса 1 180…1 230 °С или содержащие 20…30 % Fe, с температурой ликвидуса 1 200…1 230 ° С. Припой, содержащий 75 % Сu и 25 % Ni (t_пл = 1 205 °С), используется для пайки вольфрама и молибдена. Припои с палладием, несмотря на их дороговизну и дефицитность, в последнее время находят широкое применение. Палладий, во-первых, менее дефицитен, чем другие металлы платиновой группы, во-вторых, образует непрерывный ряд твердых растворов

со многими металлами (Ag, Cu, Au, Fe, Co, Ni и др.).

Использование палладия в качестве основы или в качестве легирующего элемента позволяет получать припои с температурой ликвидуса от 810 °С до температуры плавления палладия (1 552 °С).

Припои на основе палладия и никеля, легированные хромом, имеют высокую жаростойкость. Наименьшая температура ликвидуса таких сплавов 1 250 ° С. Припой состава: 24 % Pd, 33 % Сr, 39 % Ni и 4 % Si используется для пайки жаропрочных сплавов.

Палладиевые припои применяют также для пайки керамики и графита со сталью и тугоплавкими металлами. Припой состава:

60 % Pd, 40 % Ni, легированный литием и бором, применяют для пайки графита с графитом или с тугоплавкими металлами — Mo, W или их сплавами. Паяные соединения, полученные с помощью таких припоев, работают в условиях нейтронного облучения в ядерных реакторах.

Припои на основе палладия и титана имеют температуру солидуса 1 440 °С, а соединения, паянные такими припоями, могут работать при температуре до 1 640 °С.

К тугоплавким припоям с температурой плавления более 1 850 °С относятся припои на основе тугоплавких металлов. Так, для диффузионной пайки сплава тантала с содержанием 1 % W в качестве припоя применяют чистый титан. Припой в виде фольги укладывается в места соединений, а пайку производят в вакуумной печи при температуре 1 900 ºС и выдержкой 10 мин. Для капиллярной пайки применяют припой на основе Та с 40 % Hf. Пайку выполняют при температуре 2 205 º С с выдержкой 1 мин . Также для пайки тантала применяется припой, содержащий 20 % Та, 5 % Nb, 3 % W, остальное — Ti.

Для высокотемпературной пайки вольфрама используют припои с температурой плавления до 3 000 °С, в том числе чистые металлы (Ta, Nb, Ni, Cu) и сплавы (Ni–Ti, Ni–Cu, Mn–Ni–Co, Мо–В и др.).

Флюсы. Классификация флюсов осуществляется по нескольким признакам, основными из которых являются температура пайки и природа активатора.

В зависимости от температурного интервала активности паяльные флюсы подразделяются на флюсы для низкотемпературной (

Флюсы для низкотемпературной пайки по природе активатора подразделяются на канифольные, галогенидные, гидразиновые, анилиновые и др.

В качестве флюса применяют чистую канифоль. В ее составе преобладают смоляные кислоты (80…95 %), имеющие общую формулу C₁₉H₂₉COOH. Канифоль удаляет оксиды таких металлов, как медь, серебро, олово, и широко используется для пайки соединений, в том случае когда промыть изделие после пайки нельзя (остатки канифоли не вызывают коррозии). Кроме того, в качестве флюса используют раствор канифоли в спирте, а также с добавками хлоридов (ZnCl₂ и др.), анилина С₆H₅NH₂ и органических веществ,

например, гидразина N₂H₄, глицерина НОСН₂–СНОН–СН₂ОН и др. С их помощью можно паять не только медные сплавы, но также стали, оцинкованное железо, никелированное железо, конструкционные и коррозионно-стойкие сплавы.

Галогенидные флюсы используют для низкотемпературной пайки почти всех черных и цветных металлов. Чаще всего применяют хлористый аммоний NH₄Cl и хлористый цинк ZnCl₂, а также смеси, содержащие эти и другие хлориды.

Широкое применение находят флюсы на основе солянокислого гидразина N₂H₄·2HCl и анилина C₆H₅NH₂, а также других органических веществ. Соли гидразина при нагреве разлагаются с выделением водорода и хлористого водорода HCl, создающими защитную и восстановительную атмосферы. Анилин обладает высокой флюсующей активностью, причем образующийся после пайки остаток защищает шов от коррозии.

Флюсы для высокотемпературной пайки по природе активатора определяющего действия подразделяются на боридно-углекислые, галогенидные, фторборатные и др.

При пайке углеродистых сталей, чугуна и медных сплавов медно-цинковыми и серебряными припоями в качестве флюса используют борную кислоту H₃BO₃ и буру Na ₂B₄O₇ в различных сочетаниях. При пайке легированных сталей и жаропрочных сплавов флюсующего действия буры и борной кислоты недостаточно, поэтому в состав флюса вводят галогениды. Чаще всего вводят фториды натрия NaF, калия KF, лития LiF и кальция CaF ₂, а также фторбораты натрия NaBF₄ и калия KBF₄.

Флюсы для высокотемпературной пайки алюминиевых, магниевых и титановых сплавов состоят из различных хлоридов (ZnCl ₂, NH₄Cl и др.) и фторидов (NaF, KF и др.).

К вспомогательным материалам для пайки также относятся стоп-материалы, используемые при подготовке паяемой поверхности и наносимые на места, где нежелательно смачивание паяемого металла жидким припоем. Такие вещества подразделяют на стоппасты и покрытия, наносимые, например, гальваническим методом или распылением.

Технологический процесс пайки. Технологический процесс пайки изделия состоит из ряда операций и переходов, посредством которых он может быть осуществлен в определенном порядке. Помимо основной операции пайки он включает ряд подготовительных и финишных операций, обеспечивающих требуемые геометрические, механические и коррозионные характеристики паяных соединений и изделий.

К предварительным операциям пайки относится подготовка паяных поверхностей, включающая, во-первых, удаление жиров, масел, грязи, окалины и толстых неметаллических, в том числе оксидных пленок, образовавшихся в процессе химикотермической обработки, которые не могут быть удалены при пайке с помощью флюсов или газовых сред, во-вторых, обеспечение требуемой степени шероховатости паяемых участков и оптимального направления рисок, образующихся при этом, необходимых для лучшего растекания и затекания припоя в зазор, в-третьих, правильное закрепление припоя и соединяемых деталей, внесение флюса.

К финишным операциям относятся удаление остатков флюсов, зачистка соединения от наплывов припоя, обработка изделия резанием, термообработка и контроль качества паяных соединений.

Паяное соединение и его типы. Паяное соединение — элемент паяной конструкции, полученной пайкой. Паяное соединение состоит из паяного шва 1 и диффузионных зон 2 (рис. 3.77). Паяный шов — часть паяного соединения, закристаллизовавшаяся при пайке. Диффузионная зона — часть паяного соединения с измененным химическим составом паяемого материала в результате взаимной диффузии компонентов припоя и паяемого материала.

Рис. 3.77. Паяное соединение: а — схема; б — внешний вид; 1 — паяный шов; 2 — диффузионная зона; 3 — зона термического влияния; 4 — спай; 5 — паяемый материал

К паяному соединению примыкает зона термического влияния 3 — часть паяемого материала 5 с измененными под влиянием нагрева при пайке структурой и свойствами. Пограничный слой между паяным материалом и швом в сечении паяного соединения называется зоной сплавления (спаем) 4.

Тип паяного соединения определяется взаимным расположением и формой паяемых элементов. Основными типами паяных соединений являются нахлесточное, стыковое, угловое, тавровое, соприкасающееся и комбинированное (рис. 3.78).

Рис. 3.77. Типы паяных соединений: а — нахлесточное; б — телескопическое; в — стыковое; г — косостыковое; д — угловое; е — тавровое; ж — соприкасающееся; з — комбинированное

Нахлесточное паяное соединение (рис. 3.78, а) является наиболее удобным для выполнения и обеспечивает наибольшую прочность. Увеличение длины нахлестки в сочетании с пластичными высокотемпературными припоями почти всегда позволяет достичь равнопрочности соединения с основным металлом. Разновидностью нахлесточного является телескопическое паяное соединение — соединение труб или трубы с прутком (рис. 3.78, б). В практике телескопические паяные соединения получили наиболее широкое применение для соединения фланцев или втулок с трубами, втулок со стержнем, труб с заглушками, компенсаторов и т. д.

Стыковые соединения (рис. 3.78, в) при пайке используют реже, т. к. они не обеспечивают равнопрочность всего соединения. Для повышения прочности стыкового соединения его выполняют косостыковым (рис. 3.78, г). При таком соединении прочность стыка повышается и нередко достигается равнопрочность с основным металлом.

Угловое и тавровое паяные соединения (рис. 3.78, д, е) применяют сравнительно редко, т. к. их прочность в значительной степени зависит от пластичности паяного шва, модуля упругости паяемого металла и формы поверхности шва.

Соприкасающееся паяное соединение — соединение, в котором паяемые элементы различной геометрической формы соединены по линии или в точках (рис. 3.78, ж). Такие соединения допустимы при конструировании изделий, швы которых работают на сжатие или при небольших нагрузках.

Комбинированное паяное соединение — соединение, представляющее собой различные комбинации паяных соединений: нахлесточного, стыкового, косостыкового, таврового, телескопического, соприкасающегося (рис. 3.78, з).

Пайка по сравнению со сваркой имеет следующие преимущества:

1) она позволяет соединять всевозможные сплавы, в том числе плохо сваривающиеся, однородные и разнородные, а также соединять металл со стеклом, керамикой, графитом, полупроводниками;

2) за один прием можно получить протяженное соединение или сварить узел из множества заготовок. Последнее важно при массовом производстве и, кроме того, позволяет изготавливать сложные по конструкции узлы, которые невозможно сделать другими способами;

3) кромки деталей не оплавляются, поэтому при пайке можно сохранить размеры и форму деталей и паяного узла в целом;

4) многие паяные соединения можно распаивать, что важно при монтаже и ремонте в приборостроении.

Процесс пайки дешев, легко поддается механизации и автоматизации, особенно при массовом производстве. Все это обеспечило широкое применение пайки для изготовления сложных, тяжело нагруженных деталей в разных областях машиностроения (при производстве радиаторов автомобилей и тракторов, камер сгорания жидкостных реактивных двигателей, лопаток турбин, топливных и масляных трубопроводов и др.). В ремонтном производстве пайку используют для соединения или закрепления тонкостенных деталей и деталей из разнородных металлов, уплотнения резьбовых соединений, устранения пористости сварных швов чугунных и бронзовых отливок, заделки свищей, трещин и т. д.

90000 How to Use a Soldering Iron 90001 90002 90003 Weller Soldering Basics Guide 90004 90005 90002 Soldering is a useful skill to have, whether you plan to use it professionally or for DIY projects. A quality soldering iron is one of the most important tools you’ll need for your soldering projects. 90005 90002 This guide will provide a brief overview of how to use a soldering iron.It will give you the basics that apply to most soldering work, as well as tips for specific types of projects. 90005 90002 Although all soldering relies on the same principles, the techniques and tools you use may vary depending on the type of materials you’re soldering and the kind of outcome you’re intending. On this page, we’ll cover step-by-step soldering for wiring, printed circuit boards, stained glass and jewelry. 90005 90002 Here’s your introductory guide to using a soldering iron. 90005 90003 The Basics 90004 90002 The fundamentals of soldering are mostly consistent across project types.Below you’ll find information about the basics of soldering, descriptions of the equipment involved and a basic step-by-step guide for how to use a soldering iron. 90005 90018 1. What Is Soldering? 90019 90002 Soldering is a technique for joining metal parts together. It involves melting a metal known as solder into the space between two metal components. When this solder cools and hardens, it forms a permanent connection between the parts. Solder acts as a sort of metallic glue that joins elements together.90005 90002 Joining electronic components may be the most common use of soldering irons. You can also use them on piping for plumbing, engine components, arts and crafts projects and more. 90005 90018 2. What Equipment Do You Need? 90019 90002 This article is about how to use a soldering iron, but the iron itself is not the only item you’ll need. Here’s a rundown of some of the supplies you may need to use, including a soldering iron, for a soldering project. 90005 90028 90029 90030 Soldering Iron: 90031 A soldering iron supplies the heat that melts the solder.It consists of a tip, which you apply to the metal parts you want to solder together, and an insulated handle so that you can hold the iron. There are several variations of soldering irons. Often, they are electrical and use an electrical cord or battery. Some also use the combustion of a gas such as butane or an open flame. Some irons allow you to adjust the temperature of the iron. 90032 90029 90030 Solder: 90031 Solder is the substance that melts and forms the bond between the two soldered components.It is a thin wire made of one of several tin alloys. The alloys consist of either tin and lead or tin and copper. Increasingly, lead-free solders are becoming the more popular of these two options. This trend is a response to increased safety regulations as well as the environmental and health benefits of seeking lead-free alternatives. Some types of solder also include flux, a substance that gets rid of oxide layers on metal parts to help the solder adhere better. 90032 90029 90030 Soldering Station: 90031 A soldering station acts as a control station for your soldering iron if you have an adjustable iron.The station has the controls for adjusting the temperature of the iron as well as other settings. You may plug your iron into this soldering station. 90032 90029 90030 Soldering Iron Stand: 90031 You might also use a soldering iron stand, which provides a safe, sturdy place to store your iron when you are not using it. It might also include a place to keep supplies for cleaning your iron. 90032 90029 90030 Cleaning Pad: 90031 It’s essential for proper performance to keep your iron clean while you use it.You may use a cleaning pad, steel or brass wool or a damp sponge. 90032 90029 90030 Safety Glasses: 90031 Safety goggles will help protect your eyes in case of accidents and keep fumes from irritating your eyes. 90032 90029 90030 Fume Extraction Equipment: 90031 Fumes created when soldering may be toxic. Fume extraction devices pull fumes from the air to reduce health and safety risks. 90032 90057 90003 Getting Set Up 90004 90002 Before you begin using your soldering iron, you’ll have to make sure that you’ve taken all the necessary safety measures and prepared your tools.90005 90018 1. Safety Measures 90019 90002 Health and safety should always be a priority when soldering. Soldering involves extreme heat and toxic substances. While it involves certain risks, if you take the proper precautions, soldering is a relatively safe activity. 90005 90002 Before getting started, read the instructions as well as the health and safety warnings that come with all of your equipment to ensure you’re using it correctly. When soldering, wear safety glasses and keep all hair, loose clothing and jewelry secured and out of the way of your tools.You may also want to wear safety gloves. 90005 90002 Be sure that you are working in a well-ventilated area or use a fume extraction device. The fumes from flux are toxic. If the solder you are using contains lead, wash your hands after you’re done working with it. 90005 90018 2. Cleaning and Tinning 90019 90002 For your soldering iron tip to work correctly, it needs to be clean and tinned. Any contaminants or oxidation will decrease the efficiency with which it conducts heat, making your job harder and reducing the quality of your solder joints.90005 90002 Before you start soldering, clean the tip of your iron by rubbing it against your cleaning pad. If your tip is badly oxidized, you may need to apply a tip reactivator. After cleaning or reactivating it, it should appear shiny rather than dull. 90005 90002 Tinning the tip of your iron involves coating it with a layer of solder. This practice protects the tip from oxidation and improves its ability to conduct heat. Tin the tip immediately before you begin soldering. 90005 90002 In addition to cleaning and tinning the tip of your iron before each soldering session, you should also do so after every two or three joints you solder and at the end of each soldering project.This will extend the life of your soldering iron tips and improve the quality of your soldering joints. 90005 90003 Joining Parts 90004 90002 Once you’ve completed the above steps, you’re ready to solder your components together. The techniques you’ll use will vary from project to project, but the basic step-by-step instructions are as follows: 90005 90084 90029 First, determine the right temperature for your project. Which temperature to use depends on the materials you’re joining and the kind of solder you’re using.As a general rule of thumb, the best temperature to use is the one that’s as low as possible while still being high enough to get the job done. In other words, if the temperature needed to do the job is 370 degrees or above, then set the temperature to exactly 370. This will help extend the life of your tools and avoid damaging any electronic components. 90032 90029 Once your iron is heated to the appropriate temperature, pick up the iron by the handle in one hand and hold a piece of solder in the other hand.Hold the hot iron to the place where the two metal components will meet for about a second to heat them up. You want to heat the metal parts, not the solder itself. 90032 90029 Then, touch the solder to the heated components. As the solder melts, it will flow into the gaps it needs to fill. Continue to feed in solder until a sufficient amount is melted. While you need enough to form a solid connection, you do not want to have too much solder either. The right amount will vary from project to project.This typically will not take more than a few seconds. 90032 90029 Allow the solder to cool. You do not need to take any action to cause it to cool. It will do so on its own and should not take longer than a few more seconds. 90032 90029 Check the soldering joint for quality. A good connection will appear smooth, uniform and shiny. Make sure that are not any problematic gaps between the components or globs of excess solder. 90032 90095 90003 Desoldering 90004 90002 If you made a mistake in your soldering, do not worry.You can undo and fix any problem areas relatively easily. If the problem is not excess solder, you may be able to resolder over the first joint with new solder. 90005 90002 A more thorough method of correcting a soldering mistake is to reheat the solder you applied and then to use a tool such as a “solder sucker,” which is a small syringe-like device that uses vacuum pressure to remove solder. You can also use a solder wick, also called a desoldering braid, which absorbs melted solder by capillary action.90005 90003 Cleaning Up 90004 90002 After you finish a soldering session, clean and tin your soldering iron tip. After allowing the iron to cool, store it in a secure location. To further prevent oxidation, especially if you will not be using the iron for a long time, place it in a sealed container. 90005 90003 Tips for Specific Soldering Projects 90004 90002 Now that we’ve covered the basics, let’s look at how to do some specific types of soldering. 90005 90018 1. How to Use a Soldering Iron for Joining Wires 90019 90002 You can use a soldering iron to create an electrical connection between two wires.Having a tool, such as a device called a third helping hand, to hold the cables for you is very helpful. A third helping hand consists of a weighted base, metal arms and crocodile clips that hold the wires in place. You can also use a pair of pliers to a similar effect. 90005 90084 90029 First, make sure some insulation is stripped off the end of the two wires to expose the metal filaments. 90032 90029 Then, twist the filaments of each wire together so that they act more like one solid unit.90032 90029 Next, tin the wires. To do this, touch the tip of the soldering iron to each wire to heat them. Then apply solder until the wire is soaked through. There should be solder throughout all of the filaments but not so much that the cable becomes overly stiff. This will help heat spread throughout the filaments more efficiently and make soldering easier. 90032 90029 Mechanically join your wires so that the solder is not the only thing holding them together. To do this, wrap the first wire around the second, leaving enough space to wrap the second wire around the first.The turns of the cable should lay next to one another. 90032 90029 Heat the mechanically joined wires with the soldering iron and apply solder. Use enough solder to fill in all the spaces and form a reliable electrical connection. 90032 90029 Once the two wires are connected, apply a heat-shrinkable tubing to isolate the wires and keep them shielded from any outside forces. This tubing will shrink under applied heat, helping it to adhere tightly to the wires and creating a form-fitting protective coating.90032 90095 90018 2. How to Solder Printed Circuit Boards 90019 90002 Soldering parts onto printed circuit boards (PCBs) is another frequent use of soldering irons. 90005 90084 90029 Start with the tallest components, and solder interconnecting wires last. For through-hole components, place them in the correct holes in the PCB. Make sure they sit flush against the board. 90032 90029 Bend the lead of the part slightly to keep it in place. 90032 90029 Once the soldering iron has reached the desired temperature, touch it to the pad to heat the lead of the component and the pad.Make sure the temperature is correct. Too low of a temperature can create a joint that does not provide an adequate electrical connection. Too high of a temperature can damage the components and board. 90032 90029 Then, apply the solder. The solder will flow around the component liquid. Use enough to create a solid connection without gaps but not so much that you’re left with excess solder. 90032 90029 Pull the iron straight up from the component. The solder joint should form a cone-like shape.90032 90029 Check your joint to make sure that it appears shiny and that there are not any gaps or too much solder 90032 90029 If the solder joint is adequate, cut the excess component lead above the joint. 90032 90095 90018 3. How to Solder Stained Glass 90019 90002 Solder is what holds the individual pieces of glass in a work of stained glass art together. Here’s how you use solder on stained glass. 90005 90084 90029 Before soldering, make sure the stained glass pieces fit together well and that the glass is clean.90032 90029 Apply copper foil to the edges of the glass because solder will not adhere to glass. This foil should be smooth and even so that the solder flows evenly. You do not need gaps in between the pieces, but solder will be able to fill small gaps. 90032 90029 Apply a small amount of flux and then solder to each joint to help hold them in place. 90032 90029 Then apply a layer of flux to all seams. The coating should be even and light but enough to cover all foil. 90032 90029 Start soldering about a quarter of an inch from the edge of your piece.Touch the heated iron lightly to the copper foil and feed in the solder. Move the iron and solder along the foil seam. If the solder seam appears flat, try going slower and using more solder. If it’s spilling over onto the glass, try going faster. Getting this part right takes practice. 90032 90029 Once you’re done with the first side of your, flip it over carefully while holding it from the edges near the middle of the piece. Apply a small amount of flux and then solder this side. 90032 90029 To finish the outside edges, tin them by making sure all copper foil gets covered with solder.Alternatively, you can apply a U-channel came – a small, U-shaped metal piece – for a more framed look. 90032 90095 90002 Some other tips include only using solid-core solder rather than acid-core or rosin-core solder as well as not applying heat for too long in any one area as this can cause the glass to break. 90005 90018 4. How to Solder Jewelry 90019 90002 You can solder jewelry using an open-flame torch, which can provide higher temperatures, but can also do so with a soldering iron.The precise techniques vary depending on the kind of item you want to make, and there’s more room for creativity with jewelry soldering. Search online for instructions on how to make specific pieces or experiment and create your own designs. 90005 90002 For example, you can bend silver, copper or other types of wire to form rings. You can solder the two ends of the bent wire to create a single ring, or solder multiple rings together to make a necklace or bracelet. Heat the wire where you want to join it and then apply solder.90005 90002 Some helpful jewelry soldering supplies include high-quality wire cutters and a third helping hand tool. 90005 90003 Explore Weller Tools for Your Soldering Needs 90004 90002 Whichever type of soldering project you’re undertaking, the right tools and techniques are crucial. Weller offers some of the most high-quality yet affordable soldering tools on the market. For entry-level professionals and hobbyists, the WE 1010 is a perfect match. It provides the most power in its class, easy-to-use controls and cost-effective operation at an affordable price.Explore our soldering irons, stations and accessories on our website or by visiting a Weller distributor. 90005 .90000 How to Solder: Through-Hole Soldering 90001 Favorited Favorite 54 90002 Introduction 90003 90004 Soldering is one of the most fundamental skills needed to dabble in the world of electronics. The two go together like peas and carrots. And, although it is possible to learn about and build electronics without needing to pick up a soldering iron, you’ll soon discover that a whole new world is opened with this one simple skill.We here at SparkFun believe that soldering should be a skill in everyone’s arsenal. In a world of increasing technological surroundings, we believe it is important that people everywhere be able to not only understand the technologies they use everyday but also be able to build, alter, and fix them as well. Soldering is one of many skills that will empower you to do just that. 90005 90004 In this tutorial we will go over the basics of 90007 through-hole soldering 90008 – also known as plated through-hole soldering (PTH), discuss the tools needed, go over techniques for proper soldering, and show you where you can go from there.We will also discuss rework as it pertains to through-hole soldering and give you some tips and tricks that will make fixing any piece of electronics a breeze. This guide will be for beginners and experts alike. Whether you’ve never touched an iron before or are looking for a little refresher, this tutorial has a little something for everyone. 90005 90010 Suggested Reading 90011 90004 As stated earlier, you can learn about and build electronics without touching a soldering iron. If you would like to learn more about electronics theory before learning to solder, we recommend starting with some of these tutorials: 90005 90010 What is a Circuit? 90011 90004 Every electrical project starts with a circuit.Do not know what a circuit is? We’re here to help. 90005 90010 What is Electricity? 90011 90004 We can see electricity in action on our computers, lighting our houses, as lightning strikes in thunderstorms, but what is it? This is not an easy question, but this tutorial will shed some light on it! 90005 90004 If you would like to know more about building circuits without needing to pick up a soldering iron, check out our solderless breadboard tutorial: 90005 90010 How to Use a Breadboard 90011 90004 Welcome to the wonderful world of breadboards.Here we will learn what a breadboard is and how to use one to build your very first circuit. 90005 90004 Lastly, we will be building upon some previous tutorials, so it is suggested that you read about and understand these subjects before moving forward in this tutorial: 90005 90010 PCB Basics 90011 90004 What exactly IS a PCB? This tutorial will breakdown what makes up a PCB and some of the common terms used in the PCB world.90005 90010 Polarity 90011 90004 An introduction to polarity in electronic components. Discover what polarity is, which parts have it, and how to identify it. 90005 90038 90004 If you’re all caught up on the above reading, let’s dive right in! 90005 90038 90002 What is Solder? 90003 90004 Before learning how to solder, it’s always wise to learn a little bit about solder, its history, and the terminology that will be used while discussing it.90005 90004 90007 Solder 90008, as a word, can be used in two different ways. Solder, 90049 the noun 90050, refers to the alloy (a substance composed of two or more metals) that typically comes as a long, thin wire in spools or tubes. Solder, 90049 the verb 90050, means to join together two pieces of metal in what is called a 90007 solder joint 90008. So, we solder with solder! 90005 90049 Solder wire sold as a spool (left) and in a tube (right). These come in both leaded and lead-free varieties.90050 90010 Leaded vs. Lead-free Solder – A Brief History 90011 90004 One of the most important things to be aware of when it comes to solder is that, traditionally, solder was composed of mostly lead (Pb), tin (Sn), and a few other trace metals. This solder is known as 90007 leaded solder 90008. As it has come to be known, lead is harmful to humans and can lead to lead poisoning when exposed to large amounts. Unfortunately, lead is also a very useful metal, and it was chosen as the go-to metal for soldering because of its low melting point and ability to create great solder joints.90005 90004 With the adverse effects of leaded soldering known, some key individuals and countries decided it was best to not use leaded solder anymore. In 2006, the European Union adopted the Restriction of Hazardous Substances Directive (90007 RoHS 90008). This directive, stated simply, restricts the use of leaded solder (amongst other materials) in electronics and electrical equipment. With that, the use of 90007 lead-free solder 90008 became the norm in electronics manufacturing. 90005 90004 Lead-free solder is very similar to its leaded counterpart, except, as the name states, it contains no lead.Instead it is made up of mostly tin and other trace metals, such as silver and copper. This solder is usually marked with the RoHS symbol to let potential buyers know it conforms to the standard. 90005 90010 Choosing the Right Solder for the Job 90011 90004 When it comes to manufacturing electronics, it’s best to use lead-free solder to ensure the safety of your products. However, when it comes to you and your electronics, the choice of solder is yours to make. Many people still prefer the use of leaded solder on account of its superb ability to act as a joining agent.Still, others prefer safety over functionality and opt for the lead-free. SparkFun sells both varieties to allow individuals to make that choice for themselves. 90005 90004 Lead-free solder is not without its downfalls. As mentioned, lead was chosen because it performs the best in a situation such as soldering. When you take away the lead, you also take away some of the properties of solder that make it ideal for what it was intended – joining two pieces of metal. One such property is the melting point.Tin has a higher melting point than lead resulting in more heat needed to achieve flow. And, although tin gets the job done, it sometimes needs a little help. Many lead-free solder variants have what’s called a 90007 flux core. 90008 For now, just know that flux is a chemical agent that aids in the flowing of lead-free solder. While it is possible to use lead-free solder without flux, it makes it much easier to achieve the same effects as with leaded solder. Also, because of the added cost in making lead-free solder, it can sometimes be more expensive than leaded solder.90005 90004 Aside from choosing leaded or lead-free solder, there are a number of other factors to consider when picking out solder. First, there are tons of other solder compositions out there aside from lead and tin. Check out the Wikipedia solder page for an extensive list of the different types. Second, solder comes in a variety of gauges, or widths. When working with small components, it’s often better to use a very thin piece of solder – the larger then number, the smaller the gauge. For large components, thicker wire is recommended.Last, solder comes in other forms besides wire. When getting into surface-mount soldering, you’ll see that solder paste is the form of choice. However, since this is a through-hole soldering tutorial, solder paste will not be discussed in detail. 90005 90010 Purchasing Solder 90011 90004 SparkFun offers many sizes of spools of solder in both leaded and lead-free varieties. Whether you just need enough for one project or are stocking up for the coming winter, SparkFun has what you need. 90005 90004 You can visit the Soldering category of the SparkFun catalog for more solder options as well.90005 90038 90004 Now that you know how to choose the best solder for the job, let’s move on to tools and more terminology. 90005 90038 90002 Soldering Irons 90003 90004 There are many tools that aid in soldering, but none are more important than the soldering iron. If nothing else, you need at least an iron and some solder to accomplish the task at hand. Soldering irons come in a variety of from factors and range from simple to complex, but they all function roughly the same.Here, we’ll discuss the parts of an iron and the different types of irons. 90005 90010 Soldering Iron Anatomy 90011 90004 Here are the basic parts that make up a soldering iron. 90005 90100 90101 90007 Soldering Tips 90008 – No iron is complete without an iron tip. The tip is the part of the iron that heats up and allows solder to flow around the two components being joined. Although solder will stick to the tip when applied, a common misconception is that the tip transfers the solder.The tip actually transfers heat, raising the temperature of the metal components to the melting point of the solder, and the solder melts accordingly. Most irons give you the option to change your tip, should you need to replace an old tip or if you need to switch to a different style of tip. Tips come in a variety of sizes and shapes to accommodate any component. 90104 90105 90004 90049 Several types of tips. From left to right, the bevel tip (aka hoof tip), two conical tips with varying widths, and the chisel tip.90050 90005 90004 Changing the tip is a simple process that consists of either unscrewing the wand or simply pushing in and pulling out the tip 90005 90007 Tip: 90008 The efficiency of the heat transferred from the tip to the joint is dependent on the the size of the soldering iron tip that you are using. Usually, you want to have a soldering tip that is about the same width as the soldering pad you are soldering to. For more information, check out this article by Hakko. 90100 90101 90007 Wand 90008 – The wand is the part of the iron that holds the tip.This is also the part that is handled by the user. Wands are usually made of a variety of insulating materials (such as rubber) to prevent the heat of the tip from transferring to the outside of the wand, but they also house wires and metal contacts that transfer heat from the base or outlet to the tip . This dual role of heating and preventing burns makes a high quality wand much appreciated. 90104 90105 90004 90049 Two varieties of wands. Notice how the tips screw into the wand allowing for interchangeability.Some wands have tips that simply push in and pull out without any attaching mechanism. 90050 90005 90004 Some irons consist of just a wand that plugs into a wall outlet. These irons are as simple as they come, and they do not have any controls to vary the temperature. In these irons, the heating element is built directly into the wand. 90005 90049 A simple soldering iron that consists of just the wand. Some of these irons do not offer interchangeable tips. 90050 90100 90101 90007 Base 90008 – The base of the soldering iron is the control box that allows the adjusting of temperatures.The wand attaches to the base and receives its heat from the electronics inside. There are analog bases, which have a dial that controls the temperature, and there are digital bases, which have buttons to set the temperature and a display that tells you the current temperature. Some bases even have extra features such as heat profiles that allow you to quickly change the amount of heat provided to the tip for soldering a variety of components. 90104 90105 90004 90049 Two variations of a soldering iron base.On the left, a digital base, complete with control buttons and a digital display. On the right, an analog base that uses a dial to control the temperature. 90050 90005 90004 The base typically is comprised of a large transformer and several other control electronics that safely allow you to vary the heat of your tip. 90005 90004 90049 The insides of a soldering iron base 90050 90005 90100 90101 90007 Stand (Cradle) 90008 – The iron stand (often referred to as a cradle) is what houses the iron when it is not in use.The stand may seem trivial, but leaving an unattended iron laying around on your desk or workbench is a potential hazard: it could burn you, or, worse, it could burn your desk and start a fire. Again, they can be as simple as a metal stand, or they can be complex, offering an auto-shutoff feature that reduces the temperature of the tip when the wand is placed in the cradle. This helps prevent the wearing of your tip over time. 90104 90105 90004 90049 Different types of iron cradles. Notice some allow for a regular sponge while others hold a brass sponge.90050 90005 90100 90101 90007 Brass Sponge 90008 – As you solder, your tip will tend to 90007 oxidize 90008, which means it will turn black and not want to accept solder. Especially with lead-free solder, there are impurities in the solder that tend to build up on the tip of your iron, which causes this oxidization. This is where the sponge comes in. Every so often you should give your tip a good cleaning by wiping off this build-up. Traditionally, an actual wet sponge was used to accomplish this.However, using a wet sponge can drastically reduce the lifespan of your tip. By wiping your tip on a cool, wet sponge, the tip tends to expand and contract from the change in temperature. This expansion and contraction will wear out your tip and can sometime cause a hole to develop in the side of the tip. Once a tip has a hole, it is no good for soldering. Thus, brass sponges have become the standard for tip cleaning. Brass sponges pull the excess solder from your tip while allowing the tip to maintain its current heat level.If you do not have a brass sponge, a regular sponge is better than nothing. 90104 90105 90049 A brass sponge. If your iron stand does not have a spot for a brass sponge, you can get one with its own base. 90050 90038 90002 Purchasing a Soldering Iron 90003 90004 Whether you’re just beginning or a seasoned pro we’ve got a soldering iron for you! 90005 90010 Our Recommendations: 90011 90004 Looking for more options for soldering iron? Click on the button below for additional options in the catalog! 90005 Click to Here for More Soldering Iron & Stations 90038 90002 Soldering Accessories 90003 90004 Now that you know the ins and outs of a soldering iron, it’s time to discuss the other tools that will aid you on your soldering adventure.90005 90100 90101 90007 Solder Wick 90008 – is the eraser to soldering’s pencil. When dealing with issues such as jumpers or the removal of parts (desoldering), solder wick comes in very handy. Solder wick – aka desoldering braid – is comprised of thin copper wire braided together. Solder is soaked (wicked) up by the copper allowing you to “erase” extra globs of solder. 90104 90105 90100 90101 90007 Tip Tinner 90008 – is a chemical paste used to clean the tip of your soldering iron.It is composed of a mild acid that helps remove baked on residue (like when you accidentally melt your tip on a component) and helps prevent oxidation (the nasty black stuff) that accumulates on your soldering tip when not in use. 90104 90105 90100 90101 90007 Solder Vacuum (Solder Sucker) 90008 – is a great tool for removing solder left behind in through-holes when delsodering components. We’ll go over how to use this tool a little later in the tutorial. 90104 90105 90010 Solder Vacuum 90011 In stock TOL-13203 90004 The Solder Vacuum, a great (and sometimes under appreciated) little tool for solder rework.It allows you to pull the molten … 90005 7 90100 90101 90007 Water Soluble Flux Pen 90008 – Flux is a chemical agent that aids in the flowing of lead-free solder. Flux pens allow you to dab stubborn components with liquid flux to create better looking solder joints. It is recommended to clean and remove any remaining water soluble flux residue on the board.90104 90105 90100 90101 90007 No Clean Flux Pen 90008 – Flux is another chemical agent that aids in the flowing of lead-free solder. Flux pens allow you to dab stubborn components with liquid flux to create better looking solder joints. Cleaning and flux removal is not required. For those interested in removing the flux residue, isopropyl alcohol (IPA) is required. 90104 90105 90010 Other Suggested Tools 90011 90004 These tools are not necessary, but they sure do make soldering easier at times.90005 90100 90101 90007 Third Hand (Third Arm) 90008 – Third hands are great for holding PCBs, wires, and components in place while you solder. 90104 90105 90010 Third Hand 90011 In stock TOL-09317 90004 This is a solderer’s best helper, the third hand. Comes with a heavy base, two alligator clips, a soldering iron holder, and … 90005 10 90100 90101 90007 Panavise Jr.- Vacuum Base 90008 – Another great tool for holding PCBs, wires, and components in place while you solder and reworking your board. 90104 90105 90100 90101 90007 Needle Nose Pliers 90008 – Mini pliers are a must have for any hobbyist or electrical engineer. Crucial for inserting devices into breadboards and bending pins. 90104 90105 90010 Needle Nose Pliers 90011 Out of stock TOL-08793 90004 Mini Pliers.These are great little pliers! A must have for any hobbyist or electrical engineer. Crucial for inserting device … 90005 1 90010 Electronic Snippers 90011 In stock TOL-10447 90004 While our small diagonal cutters are great for hobby use, sometimes you need something with a little more bite.These electro … 90005 5 90010 Diagonal Cutters 90011 Out of stock TOL-08794 90004 Mini Diagonal Cutters. These are great little cutters! A must have for clipping leads and extra solder tails.4 “long. 90005 2 90100 90101 90007 Flush Cutters 90008 – Giving you a way to cut leads very cleanly and close to the solder joint. Diagonal cutters are good, but if you really need to get up close and personal, flush cutters are the way to go. 90104 90105 90010 Flush Cutters – Xcelite 90011 In stock TOL-14782 90004 These are simple flush cutters from Excelite that give you a way to cut leads very cleanly and close to the solder joint.90005 1 90010 SparkFun Safety Glasses 90011 In stock SWG-11046 90004 With these SparkFun Safety Glasses you’ll have a pair of lightweight, economical, and stylish lenses to protect your precious … 90005 3 90100 90101 90007 Monocle 90008 – Useful for inspecting your solder joints and SMD components on a PCB.The LED provides sufficient light at the working distance. 90104 90105 90007 Bundled Kits! 90008 Check out the following tool kits with some of the soldering irons and accessories listed earlier! 90010 SparkFun Tool Bag Kit 90011 Out of stock TOL-14683 90004 This assortment of tools is great for those of you who need a portable tool assembly with plenty of room to add your own.90005 90038 90002 Soldering Your First Component 90003 90004 Let’s put all these tools into action. This first video will go over the basics of soldering your first component – headers! 90005 90281 90282 90004 Check out the Vimeo version here. 90005 90010 Recap 90011 90004 It’s really that easy! Follow Dave’s simple rules to make every solder connection a good one. 90005 90100 90101 Be cautious when handling hot irons 90104 90101 Use third hands or vices to hold boards while you solder 90104 90101 Set your iron at a good medium heat (325-375 degrees C) 90104 90101 If you see smoke coming from your solder, turn down the heat 90104 90101 Tin your tip with solder before each connection to help prep the joint 90104 90101 Use the side of the tip (aka the sweet spot), not the very tip of the iron 90104 90101 Heat both the pad and the part you want to solder evenly and at the same time 90104 90101 Pull the solder away, then the iron 90104 90101 A good solder joint should look like a volcano or Hersey kiss, not a ball or clump 90104 90105 90004 We’ve also put together this digram to help you better understand what makes a good solder joint.90005 90004 90049 Click for a larger image. 90050 90005 90004 When you are finished, tin the tip to increase its life before turning your soldering iron off. 90005 90038 90002 Advanced Techniques and Troubleshooting 90003 90010 Advanced PTH 90011 90004 Once you get the basics of creating good solder joints, it’s time to learn some of the more advanced PTH techniques that you can utilize. This video goes over using flux, removing solder jumpers, desoldering components, along with some other tips and tricks.90005 90004 90325 90282 90005 90004 Here are some other tips for PTH soldering: 90005 90100 90101 90004 Desoldering can often be the best way to learn how to solder. There are many reasons to desolder a part: repair, upgrade, salvage, etc. Many of the techniques used in the video aid in the desoldering process. 90005 90104 90101 90004 There is another method of removing solder from through-holes that we refer to as the slap method. 90005 90104 90101 90004 If you’re ever unsure if the solder joint you created is making an electrical connection, you can use a multimeter to test for continuity.90005 90104 90105 90010 Holding Headers Against a Board 90011 90004 For those that have the dexterity, you can install a row of headers by holding the pins against the board! You can try to use tape and sticky tack as mentioned earlier. Below is an example of installing female headers on the ProtoShield. However, you can follow along with male headers or use this technique to solder headers on any board. 90005 90004 Grab a female stackable header and slide it from the top side of a shield.With your soldering hand, pull the header with your index finger and thumb toward the edge of the board. Using your other hand, push against the header using your index finger and grip the board with your thumb. Hold the header down with your middle finger. Make sure to avoid touching any header pins where the soldering iron will touch. 90005 90350 90351 90352 90353 90352 90353 90356 90357 90004 Grab the soldering iron with your soldering hand and tack on one pin. Repeat for each header.After tacking one pin for each header, you will want to ensure that the pins are straight and perpendicular to your board. If they are not, you can try to reheat the header pin and adjust the header’s alignment. 90005 90004 If the headers are aligned, you can solder the rest of the header pins on the board to finish installing the headers on the board! 90005 90010 Advanced SMD 90011 90004 Looking for more tips and tricks with just your soldering iron? Check out these advanced techniques to rework SMD components according to Pete.90005 90004 90367 90282 90005 90010 Cleaning Flux Residue 90011 90004 When working with lead-free solder, flux tends to get everywhere, be it from the flux in the solder or from external flux applied by the user. Certain types of flux can corrode the PCB and components over time, thus it’s good to know how to clean your PCBs so they’re free of any flux residue. This can also cause a high-resistance shorts between pins as a result of the moisture in the air and tiny dendrites forming.Common problems can range from uploading code to an Arduino using a serial-to-USB converter to errors when sending data through I 90373 2 90374 C. 90005 90004 How do they look like? Well, lets take a look at the images below. The image on the left shows water-soluble flux residue on the solder joints. These can appear as a yellow or brown coating on or around the solder joints. The image on the right shows no clean flux that was used on the SparkFun Edge. These can appear gunky and white on the board.It’s non-conductive so it can be left on the board. 90005 90004 If you have water-soluble flux residue on the board, you will want to remove it from the board. No clean flux, you should not need to remove it. The simplest way to clean water soluble-flux from the board is to use a small brush with stiff bristles (toothbrushes work great) or a Q-tip. Then scrub the solder joint with hot, de-ionized water to remove the water-soluble flux. Isopropyl alcohol can be used as a substitute for water.If you must remove no-clean flux from the board, the best approach would be to use isopropyl alcohol, rather than water. Keep in mind, you’ll have to check the documentation for your solder for the proper cleaning methodology as other types of flux may require acetone. 90005 90350 90351 90352 90353 90352 90353 90352 90353 90356 90351 90352 90391 Removing Water Soluble Flux with a Brush 90392 90353 90352 90391 Removing Water Soluble Flux with a Q-Tip 90392 90353 90352 90391 Removing No Clean Flux with a Q-Tip 90392 90353 90356 90357 90004 If you are soldering more than a few boards, it may be necessary to clean them in batches.For this, we recommend a crock pot filled with distilled water. The distilled water keeps other impurities and contaminants away from your circuit. Below shows an image of a battery holders being cleaned. Not all boards can be dunked in water like this. So you may need to manually clean the solder joints. Having a crock pot full of hot, de-ionized water will make the process faster. 90005 90350 90351 90352 90353 90352 90353 90356 90351 90352 90391 Dunking Boards in a Crock Pot 90392 90353 90352 90391 Manually Cleaning an LED Strip’s Solder Joints 90392 90353 90356 90357 90004 Make sure to avoid getting water sensors or components that can retain water.Certain components are sensitive to water, so you should avoid dunking those boards in water and be careful about getting these components wet. Here is a short list of components that should avoid contact with water. If water gets trapped in them and you power the board, it will probably damage the component. 90005 90100 90101 Character LCDs 90104 90101 7-Segment LED Displays 90104 90101 Batteries 90104 90101 GPS Modules 90104 90101 Wireless Modules 90104 90101 Barometric Pressure Sensors 90104 90101 Slide Potentiometers 90104 90101 Microphones 90104 90101 Speakers 90104 90101 Heart Rate Monitor ICs 90104 90105 90004 When you are finished cleaning the board, you’ll want to remove any excess water off the board.Compressed air works wonders so that you do not have to wait for it to evaporate. You can also paper towels to dry a board but it may leave pieces of lint behind. Thus low-lint wipes to dry a board would be better. If you have a hot air gun, you can also use it to heat the board up. Just make sure to not melt anything on the board. 90005 90350 90351 90352 90353 90352 90353 90356 90351 90352 90391 Compressed Air to Dry Board 90392 90353 90352 90391 Low Lint Wipes Drying a Board 90392 90353 90356 90357 90004 It’s not 100% necessary to clean your board, however, it will increase the life of your circuit tremendously.Additionally, data sent through serial will be reliable when the board is clean. For more information on PCB cleaning, click below. 90005 Electronics Assembly: Washing 90010 Testing and Troubleshooting Solder Joints 90011 90004 Once you are done cleaning, feel free to check your solder joints with a multimeter set to continuity mode as stated earlier. This is useful if you run into problems and need to check if a pin is soldered correctly to a board. For more information, check out our tutorial on how to use a multimeter.90005 90004 Looking for troubleshooting tips? Check out the hardware checklist in our tutorial for more information! 90005 90002 Resources and Going Further 90003 90004 We’ve only just begun to travel down the soldering rabbit hole. Once you have mastered PTH soldering, you can try your hand at these other skills and tutorials. 90005 90004 For more information about soldering castellated mounting holes to pads, check out our guide on soldering castellated holes.90005 90010 How to Solder: Castellated Mounting Holes 90011 90484 May 12, 2015 90 485 90004 Tutorial showing how to solder castellated holes (or castellations). This might come in handy if you need to solder a module or PCB to another PCB. These castellations are becoming popular with integrated WiFi and Bluetooth modules. 90005 90004 Or check out the following tutorials to solder a surface mount component (SMD) to a breakout board.90005 90004 Looking for more tutorials with soldering? Try taking a look at any tutorial tagged with soldering! 90005 90010 LilyPad Safety Scarf 90011 90004 This scarf is embedded with a ribbon of LEDs that illuminate when it gets dark out, making yourself more visible to vehicle and other pedestrians. 90005 90004 And, of course, what’s a soldering tutorial without something to solder. SparkFun sells a variety of kits that are great for honing your soldering skills.There’s even a Learn to Solder series of kits that have all the tools necessary to get started. 90005 .90000 Electronics Club – Soldering Guide 90001 Electronics Club – Soldering Guide – how to solder, precautions, heat sink, desoldering, burns treatment 90002 90003 How to solder | Heat sink | Components | Solder | Desoldering | Burns 90004 90003 For information about soldering irons and other tools please see the Tools page. 90004 90003 Download a PDF version of this page: Soldering Guide (PDF) 90004 90009 90010 How to Solder 90011 90012 First a few safety precautions: 90013 90003 90015 Never touch the element or tip of the soldering iron.90016 They are very hot (about 400 ° C) and will give you a nasty burn. 90004 90003 90015 Take great care to avoid touching the mains flex with the tip of the iron. 90016 The iron should have a heatproof flex for extra protection. An ordinary plastic flex will melt immediately if touched by a hot iron and there is a serious risk of burns and electric shock. 90004 90003 90015 Always return the soldering iron to its stand when not in use. 90016 Never put it down on your workbench, even for a moment! 90004 90003 90015 Work in a well-ventilated area.90016 The smoke formed as you melt solder is mostly from the flux and quite irritating. Avoid breathing it by keeping you head to the side of, not above, your work. 90004 90003 90015 Wash your hands after using solder. 90016 Traditional solder contains lead which is a poisonous metal. 90004 90003 If you burn yourself see First Aid for Burns. 90004 90036 90003 90004 90003 I strongly recommend using a soldering iron with a 90015 heatproof silicone cable 90016 for safety because it will not melt if accidentally touched with the hot iron.90004 90003 For example this 230V soldering iron from Rapid Electronics: soldering iron 90004 90012 Preparing the soldering iron: 90013 90003 90015 Place the soldering iron in its stand and plug in. 90016 The iron will take a few minutes to reach its operating temperature of about 400 ° C. 90004 90003 90015 Dampen the sponge in the stand. 90016 The best way to do this is to lift it out the stand and hold it under a cold tap for a moment, then squeeze to remove excess water. It should be damp, not dripping wet.90004 90003 90015 Wait a few minutes for the soldering iron to warm up. 90016 You can check if it is ready by trying to melt a little solder on the tip. 90004 90003 90015 Wipe the tip of the iron on the damp sponge. 90016 This will clean the tip. 90004 90003 90015 Melt a little solder on the tip of the iron. 90016 This is called ‘tinning’ and it will help the heat to flow from the iron’s tip to the joint. It only needs to be done when you plug in the iron, and occasionally while soldering if you need to wipe the tip clean on the sponge.90004 90012 You are now ready to start soldering: 90013 90003 90015 Hold the soldering iron like a pen, near the base of the handle 90016 (Imagine you are going to write your name). Remember to never touch the hot element or tip. 90004 90003 90015 Touch the soldering iron onto the joint to be made. 90016 Make sure it touches both the component lead and the track. Hold the tip there for a few seconds and … 90004 90003 90015 Feed a little solder onto the joint. 90016 It should flow smoothly onto the lead and track to form a volcano shape as shown in the diagram.Apply the solder to the joint, not the iron. 90004 90003 90015 Remove the solder, then the iron, while keeping the joint still. 90016 Allow the joint a few seconds to cool before you move the circuit board. 90004 90003 90015 Inspect the joint closely. 90016 It should look shiny and have a ‘volcano’ shape. If not, you will need to reheat it and feed in a little more solder. This time ensure that 90015 both 90016 the lead and track are heated fully before applying solder. 90004 90003 If you burn yourself see First Aid for Burns below.90004 90093 90003 90004 90003 Short of money for your electronics projects? Sell ​​your old iPhone, iPad, MacBook or other Apple device: macback.co.uk 90004 90009 90010 Using a heat sink 90011 90101 90003 Some components, such as transistors, can be damaged by heat when soldering so if you are not an expert it is wise to use a heat sink clipped to the lead between the joint and the component body. You can buy a special tool, but a standard crocodile clip (without a plastic cover) works just as well and is cheaper.90004 90003 The heat sink works by taking some of the heat being supplied by the soldering iron and this helps to prevent the component’s temperature increasing too much. 90004 90003 Rapid Electronics: crocodile clip 90004 90009 90009 90010 Soldering Advice for Components 90011 90112 90003 It is very tempting to start soldering components onto the circuit board straight away, but please take time to identify all the parts first. Sticking them onto a sheet of scrap paper and labelling each one is worthwhile and you are less likely to make a mistake if you do this.90004 90003 90015 Some ICs are static sensitive 90016 and will be supplied in antistatic packaging – leave these ICs in their packaging until you need them, then earth your hands by touching a metal water pipe or window frame before handling the ICs. 90004 90119 90120 Stick the components onto paper using sticky tape. 90121 90120 Identify each component and write its name or value beside it. 90121 90120 Add the labels (R1, R2, C1 etc.) used in the project diagram too if necessary. 90121 90120 Resistor values ​​can be found using the colour code explained on the resistors page.You can make your own colour code calculator. 90121 90120 Capacitor values ​​can be a little more difficult, the various labelling systems are explained on the capacitors page. 90121 90130 90012 Some components require special care when soldering. 90013 90003 Many must be placed the correct way round and a few can be easily damaged by the heat from soldering. 90004 90003 The table shows advice for the various components and a suggested order to put them on the board. Generally it is best to start with the smallest parts but for stripboard it is helpful to start with the IC holder (s) as a reference point for other parts.90004 90012 Wire links 90013 90003 90015 Wire links between points on the board 90016 can be made with plastic-coated single core wire which will need stripping, or tinned copper wire if the link will not touch other parts. Tinned copper wire looks just like solder but you can feel the difference, it is stiffer than solder (and it will not melt). 90004 90003 90015 Wires to parts off the board 90016 need to be flexible so use plastic-coated stranded wire for these, a popular type is 7 / 0.2mm wire (7 strands of 0.2 mm diameter wire). 90146 Single core wire is unsuitable because it snaps when repeatedly flexed. 90147 90004 90003 Rapid Electronics: 7 / 0.2mm wire pack 90004 90151 90152 90153 90015 Soldering Components 90016 90156 Put components on the board in this order: 90157 90158 90152 90153 90161 90015 1. IC Holders 90016 90156 Connect the correct way round – the notch will remind you which way to place the IC. 90146 Do NOT insert the ICs yet. 90147 90157 90158 90152 90153 90171 90015 2.Resistors 90016 90156 Connect either way round. 90157 90158 90152 90153 90015 3. Small value capacitors 90016 90181 90156 Small value capacitors (<1μF) are not polarised. Connect either way round. 90157 90158 90152 90153 90015 4. Electrolytic capacitors (1μF +) 90016 90189 90156 Connect the correct way round, look for a + or - near one lead. They may be radial style (both leads at one end) or axial style (leads at each end). 90157 90158 90152 90153 90195 90015 5.Diodes 90016 90156 Connect the correct way round. The stripe marks the cathode (line on symbol) usually labelled k on diagrams. 90156 90146 For germanium diodes use a heat sink. 90147 90157 90158 90152 90153 90206 90015 6. LEDs 90016 90156 Connect the correct way round, the cathode is the short lead. The diagram will have a or + for anode, k or - for cathode. 90157 90158 90152 90153 90214 90015 7. Transistors 90016 90156 Transistors have 3 'legs' (leads) so take extra care to connect them correctly.They can be damaged by heat, use a heat sink until you can solder quickly. 90157 90158 90152 90153 90222 90015 8. Wire Links 90016 90156 Links between points on the board can be made with plastic-coated single core wire, or tinned copper wire if the link will not touch other parts. 90157 90158 90152 90153 90015 9. Parts with their own wires 90016 90156 Battery clips, buzzers etc. Connect the correct way round if necessary. 90157 90158 90152 90153 90015 10. Wires to parts off the board 90016 90239 90156 Use stranded wire for switches, relays, loudspeakers, variable resistors etc.90157 90158 90152 90153 90015 11. ICs (chips) 90016 90247 90156 Connect the correct way round, look for the notch or dot near pin 1. Make sure all the pins are lined up with the socket before pushing down firmly with your thumb. 90157 90158 90251 90009 90010 What is solder? 90011 90255 90003 90015 Traditional solder 90016 is an alloy (mixture) of tin and lead, typically 60% tin and 40% lead. It melts at a temperature of about 200 ° C. 90004 90003 Modern 90015 lead-free solder 90016 is an alloy of tin with other metals including copper and silver.It melts at a temperature of about 220 ° C. 90004 90003 Coating a surface with solder is called 'tinning' because of the tin content of solder. 90004 90003 90267 Photograph © Rapid Electronics 90268 90004 90003 90015 Always wash your hands after using solder 90016, this is especially important with traditional solder because it contains lead which is toxic. 90004 90003 The best size of solder for electronics is 22 swg (swg = standard wire gauge) and I recommend using lead-free solder.90004 90003 Rapid Electronics: lead-free solder 90004 90003 Solder for electronics use contains tiny cores of flux, like the wires inside a mains flex. The flux is corrosive, like an acid, and it cleans the metal surfaces as the solder melts. This is why you must melt the solder actually on the joint, not on the iron tip. Without flux most joints would fail because metals quickly oxidise and the solder itself will not flow properly onto a dirty, oxidised, metal surface. 90004 90009 90009 90010 Desoldering 90011 90003 At some stage you will probably need to desolder a joint to remove or re-position a wire or component.There are two ways to remove the solder: 90004 90286 1. With a desoldering pump 90287 90003 Also known as a 'solder sucker'. It is best to use one with an ESD (electrostatic discharge) nozzle to protect some ICs which can be damaged by static electricity. 90004 90119 90120 Set the pump by pushing the spring-loaded plunger down until it locks. 90121 90120 Apply both the pump nozzle and the tip of your soldering iron to the joint. 90121 90120 Wait a second or two for the solder to melt.90121 90120 Then press the button on the pump to release the plunger and suck the molten solder into the tool. 90121 90120 Repeat if necessary to remove as much solder as possible. 90121 90120 The pump will need emptying occasionally by unscrewing the nozzle. 90121 90130 90003 Rapid Electronics: desolder pump 90004 90306 90003 Using a desoldering pump (solder sucker) 90004 90286 2. With solder remover braid 90287 90003 The copper braid acts as a wick for the molten solder which readily flows onto the braid, away from the joint.90004 90119 90120 Apply both the end of the copper braid and the tip of your soldering iron to the joint. 90121 90120 As the solder melts most of it will flow onto the braid, away from the joint. 90121 90120 Remove the braid first, then the soldering iron. 90121 90120 Cut off and discard the end of the braid coated with solder. 90121 90130 90003 Rapid Electronics: desolder braid 90004 90003 After removing most of the solder from the joint (s) you may be able to remove the wire or component lead straight away (allow a few seconds for it to cool).If the joint will not come apart easily apply your soldering iron to melt the remaining traces of solder at the same time as pulling the joint apart, taking care to avoid burning yourself. 90004 90009 90010 First Aid for Burns 90011 90003 Most burns from soldering are likely to be minor and treatment is simple: 90004 90119 90120 90015 Immediately cool the affected area under gently running cold water. 90016 90156 Keep the burn in the cold water for at least 5 minutes (15 minutes is recommended).If ice is readily available this can be helpful too, but do not delay the initial cooling with cold water. 90121 90120 90015 Do not apply any creams or ointments. 90016 90156 The burn will heal better without them. A dry dressing, such as a clean handkerchief, may be applied if you wish to protect the area from dirt. 90121 90120 90015 Seek medical attention if the burn covers an area bigger than your hand. 90016 90121 90130 90003 To reduce the risk of burns: 90004 90350 90120 Always return your soldering iron to its stand immediately after use.90121 90120 Allow joints and components a minute or so to cool down before you touch them. 90121 90120 Never touch the element or tip of a soldering iron unless you are certain it is cold. 90121 90357 90009 90003 Rapid Electronics have kindly allowed me to use their images on this website and I am very grateful for their support. They stock a wide range of components, tools and materials for electronics and I am happy to recommend them as a supplier. 90004 90009 90286 Privacy Policy & Cookies 90287 90003 90267 This website does not collect personal information.If you send an email your email address and any personal information will be used only to respond to your message, it will not be given to anyone else. This website displays advertisements, if you click on these the advertiser may know that you came from this site and I may be rewarded. No personal information is passed to advertisers. This website uses some cookies classed as 'strictly necessary', they are essential for operation of the website and can not be refused but they do not contain any personal information.This website uses the Google AdSense service which uses cookies to serve advertisements based on your use of websites (Including this one) as explained by Google. To learn how to delete and control cookies from your browser please visit AboutCookies.org. 90268 90004 90003 electronicsclub.info © John Hewes 2020 90004 90003 Website hosted by Tsohost 90004 .90000 13 Common PCB Soldering Problems to Avoid 90001 90002 Hand soldering has always been considered a hallmark skill to have in every electronics maker's repertoire of geeky skills. Soldering has never been rocket science. It can be a fun activity for beginners to try out and with enough practice, it is an easy skill to pick up. 90003 90002 Although it is possible for anyone to throw down solder onto PCBs, whether you get classy solder joints or downright caveman quality ones is a different matter altogether.With components becoming smaller and more compact, the chances of soldering issues occurring have become higher. And if your PCB is going to be used for an important application, it will be more important than ever to know what a good solder joint looks like. 90003 90006 Components are getting smaller and smaller ... 90007 (Source: Surfacemountprocess) 90002 Here's a guide to help you discern what's good and what's not, so that you may be sure to avoid these soldering issues for your home projects, or just to be able to do a quality assessment on assembled PCBs received from a third party.90003 90010 90011 Ideal Solder Joints 90012 90013 90002 When looking for solder defects, it's helpful to have an image of an ideal solder joint for comparison. 90003 90016 90011 The Ideal Through-hole Solder Joint - It's like a Hershey's Kiss 90012 90019 90020 90021 90022 90023 90021 90025 90023 90027 90002 An ideal through-hole solder joint 90007 (Source: unbrokenstring) 90003 90002 The ideal solder joint for through-hole components is a "concave fillet", which has a smooth and shiny concave surface at an angle of 40 to 70 degrees from the horizontal, which looks just like the shape of a Hershey's kiss.It can be achieved when the soldering iron is at the right temperature, with the oxide layer cleaned from the PCB contacts. 90003 90016 90011 The Ideal Surface Mount Solder Joint 90012 90019 90002 Similarly, good SMD solder joints have smooth, concave fillets as well. 90003 90039 An ideal SMD solder joint 90007 (Source: poeth) 90007 90002 Hence, the general characteristics of a good solder joint: 90003 90002 - Has good and complete wetting 90003 90002 - Has a concave fillet 90003 90002 - Is shiny and clean 90003 90016 90011 Bad Solder Joints 90012 90019 90002 Unfortunately, there are many ways for solder joints to go wrong, as solder always seems to go where it is not supposed to.90003 90056 Solder joint quality for through-hole components 90007 (Source: gaudi.ch) 90007 90010 90011 1. Solder Bridging 90012 90013 90020 90021 90065 90023 90021 90068 90023 90027 90002 Nasty solder bridges - through-hole and surface mount 90007 (Source: Pimoroni, Youtube-Androkavo) 90003 90002 Of the many problems caused by smaller and smaller components, solder bridging takes the top of the list. It forms when two or more solder joints become inadvertently connected, usually due to the excessive application of solder between joints or using soldering tips that are too big or too wide.Identifying a solder bridge can sometimes be challenging, as solder bridges can be microscopic in size. If left undetected, it can lead to a short circuit and cause a component to burn up. 90003 90002 A solder bridge can be fixed by holding your solder iron in the middle of the bridge to melt the solder, and drawing it through to break the bridge. If the solder bridge is too large, excess solder can be removed a solder sucker. 90003 90010 90011 2. Excessive Solder 90012 90013 90082 Excessive solder is easily recognized by their round shape 90007 (Source: Androkavo, Youtube) 90002 If you get too enthusiastic and apply too much solder onto a pin, excess buildup is what you'll get, characterized by its rounded shape.A common beginner's assumption is the more solder the better but while more solder should increase the amount of material forming the joint, it is difficult to know what actually happened beneath that mass of solder. There still lies a possibility that neither the pin nor the pad is properly wetted. It also increases the risk of solder bridges forming so it's better to be safe than sorry. Enough solder to adequately wet the pin and the pads thoroughly is usually sufficient and the concave surface remains the best shape to have as it allows us to better access the wetting of the joint.90003 90016 90011 3. Solder Balling 90012 90019 90090 90002 Solder balls are also one of the most common soldering defects that occur typically with wave or reflow soldering. It appears as a small sphere of solder that adheres itself to a laminate, resist, or conductor surface. Solder balls can be a result of several factors, such as improper solder paste printing, poor reflow temperature settings, rough PCB design, or the usage of oxidized electronics components. 90003 90016 4.Cold Joint 90019 90095 A lumpy and dull cold joint 90007 (Source: Androkavo, Youtube) 90002 The surface of cold joints appears dull, lumpy and pock-marked. This is typically caused by insufficient heat being transferred to the joint to completely melt it which may be a result of a number of different things. The solder iron or the joint itself may not have been given enough time to heat up sufficiently, the iron temperature may not be set high enough to melt the particular solder type being used (e.g. lead-free solder has a higher melting temperature) or, it may be a result of the design of the pads and traces themselves. For example, a pad connected directly to the ground plane without thermal relief considerations will cause the heat of the solder iron to be lost to the ground plane. If you find a stubborn solder joint that refuses to liquify then the design may be at fault. If not properly rectified, cracks will be more likely to form over time, leading to eventual failure. 90003 90016 90011 5.Overheated Joint 90012 90019 90103 A burnt solder joint (more like burnt solder mask) 90007 90002 Just as too little heat will cause wonky joints, too much heat will also give you a splitting headache. Overheated solder joints can result from the soldering iron temperature being set too high, or result from solder failing to flow, possibly due to the surface of the pad or lead already having a layer of oxide, preventing sufficient heat transfer and therefore leaving you heating the joint for too long.Hopefully, the damage caused will not be severe (perhaps just some burnt flux) but it may cause pads to lift entirely, killing the board or requiring costly repairs. Avoid this by choosing the correct solder iron temperature and use flux to clean dirty looking joints and pads. 90003 90016 90011 6. Tombstoning 90012 90019 90020 90021 90113 90023 90021 90116 90023 90027 90002 The tombstone defect - surface mount and through-hole 90007 (Source: Youtube - BermNarongGamer, Epectec) 90003 90002 A tombstoned component is usually a surface mount component, like a resistor or a capacitor, with one side lifted off from the pad.Ideally, the solder will attach to both pads and begin the wetting process. But if the solder on one pad has not completed its wetting process, one side of the component will tilt on its side, looking like a tombstone, and hence its ominous name. 90003 90002 For reflow soldering, anything that would cause the solder paste on one pad to melt before the other can cause tombstoning. For example, lack of thermal relief design or unequal thicknesses of the traces that connect to the pads. For wave soldering, components with large bodies may be physically pushed by the incoming solder wave, causing the component to be fixed in the tombstone fashion.Layout engineers must consider the direction of the wave when designing boards destined for wave soldering. 90003 90016 7. Insufficient Wetting (Through-hole) 90019 90128 The pad and the pin are not fully wetted 90002 Joints that are not fully wetted are weak and do not form a strong connection with the board. Ideally, the solder should achieve 100% wetting with the pad and pin, leaving no gaps or spaces exposed. Insufficient wetting of the pins and pad results from failure to apply heat to both the pin and pad, and not giving the solder enough time to flow.Sometimes, it could just be due to a dirty board. The technique to repair this is to clean the board thoroughly and evenly heat both the pad and the pin. 90003 90016 8. Insufficient Wetting (Surface Mount) 90019 90133 3 pins on the right are not fully wetted. Only the leads were heated so the solder did not flow onto the pads 90002 Similarly, SMD components can also suffer from insufficient wetting. In the image above, 3 pins of an SMD component do not have good wetting with their respective pads.The solder on the pins had failed to flow onto the pads, as the pin was heated instead of the pad. The solution to repairing this defect is to heat the solder pad with the tip of your soldering iron, then applying more solder until it flows and melts together with the solder already on the pin. 90003 90016 9. Solder Skips 90019 90138 Solder noticeably absent on the left pad 90007 (Source: Epectec) 90002 A solder joint that is not wetted with solder is generally referred to as a solder skip.It occurs when solder skips over a surface mount pad, resulting in an open circuit. The cause of solder skips can be a combination of slip-ups in the design or during manufacturing. You may have placed down an uneven pad size, or your manufacturer could have used an incorrect wave height between your board and the soldering wave. 90003 90016 90011 10. Lifted pads 90012 90019 90146 (Source: Kitronik) 90002 A lifted pad is a solder pad that has become detached from the surface of the PCB possibly due to excessive force on an existing joint or excess heat.Such pads are difficult to work with since the pad is very fragile and can easily tear from the trace. Every effort should be made to adhere the pad back onto the board before attempting to solder to it. 90003 90016 90011 11. Solder Starved 90012 90019 90153 The solder has not fully filled the through-hole in this figure 90007 (Source: Kitronik) 90002 As its name suggests, a solder-starved joint does not have enough solder to form a solid electrical connection. Here, it is likely that insufficient heat was applied to the lead, resulting in a poor connection.It is possible that this joint will work as there is still electrical contact made. Nevertheless, a solder-starved joint is likely to fail eventually as cracks develop over time and weaken the joint. Fortunately, rescuing a solder-starved joint is not difficult. Simply reheat the joint and add more solder. 90003 90016 12. Solder Splashes / Webbing 90019 90020 90021 90161 90023 90021 90164 90023 90027 90002 Soldering splashes on the traces (left) and around surface mount components (right) 90007 (Source: Workmanship.nasa & Texas Instruments) 90003 90002 These bits of solder stick onto the solder mask in untidy splatters, giving the appearance of a spider's web. These irregularly shaped threads are caused by insufficient use of a fluxing agent or the existence of pollutants on the surface of the boards during wave soldering, and they threaten to cause shorts. 90003 90016 13. Pin Holes and Blow holes 90019 90020 90021 90176 90023 90021 90179 90023 90027 90002 A pin hole defect (left) and a blow hole defect (right) 90007 (Source: eptac) 90003 90002 Pin holes and blow hole defects can be easily recognized as they appear as a hole in a solder joint.The terms pin or blow hole will give a clue to the size of the hole, with pin referring to small holes and blow holes being much larger holes. Rather than being a result of bad hand soldering skills, pin and blow holes are usually formed during the wave soldering process. Moisture within the boards is heated into gas during the soldering operation, and escape through the solder when it is still in a molten state. Voids are formed when the gas continues to escape when the solder joint solidifies.Some ways that are employed to avoid this problem is by baking or preheating the boards to take the moisture out, and having a minimum copper plating thickness of about 25um in the through-holes. 90003 90010 What can you do to avoid soldering problems? 90013 90002 While there is no foolproof method to completely prevent soldering problems, there are some good habits we can adopt during PCB design and soldering to reduce the risk of running into soldering issues. 90003 90016 1. Consider solder mask design 90019 90002 Typically green in color, the solder mask the thin polymer coating applied to the surface of PCBs to protect the copper from the environment.Besides preventing oxidation, they also function to prevent solder bridges from forming as well, as solder does not adhere well to the coating. Hence, solder mask can be designed between pads to form a solder mask dam. This is especially helpful for ICs and BGAs where the gap between pads can be as small as a few thousandths of an inch. 90003 90016 2. Place Fiducial marks 90019 90002 Fiducial marks are round solder mask openings with a round bare copper in its center, that are placed on your PCB board during the PCB design stage.There are panel fiducial marks and individual component fiducial marks for components requiring special treatment. Pick-and-Place machines see them as reference points on the PCB to align SMD components on your board during assembly. When used correctly, placement accuracy can be improved. Similarly, if fiducial marks are poorly designed (e.g. poor placement or not enough fiducials), they can lead to poor orientation, increasing the risk of soldering issues. 90003 90199 Position of fiducial marks on a PCB 90007 (Source: pcb-3d) 90016 3.Cleaning and Tinning the tip of your solder iron 90019 90002 Poor tip maintenance is one of the leading causes of badly hand-soldered joints. Any contaminants or oxidation on the tip would decrease the solder iron's ability to conduct heat, which in turn would reduce the quality of your solder joints. Hence, it is important to care of your solder tips. Before you start soldering, remember to clean the tip of your iron by rubbing it against a cleaning pad. If your soldering tip is already badly oxidized, you can use a tip activator to rescue it.Simply dip it into the paste-like substance, move it around and let the abrasives do their work, and the surface will be shiny again. 90003 90002 After that's done, the tip of your iron should also be tinned. Tinning the tip of your iron means to coat the tip with a layer of solder to protect the tip from oxidation and to improve its ability to conduct heat. Clean and tin your solder iron tip after every two or three joints soldered, and another one time at the end of each soldering session.Doing so would extend the life of your soldering iron and improve the quality of your solder joints! 90003 90207 There's nothing like a good shiny solder tip 90007 (source: weller-tools) 90016 4. Practice makes Perfect 90019 90002 Soldering is a skill that gets better as you practice more! You can practice as much as you like on an old circuit board or a soldering practice board, before you embark on real projects that are too precious to ruin. Try out a variety of techniques, find a way for the solder iron to best fit in your hand, gauge how long you have to keep the solder and tip in place and make tons of mistakes.90003 90002 To make solder practice more convenient, Seeed has rolled out a pen-like miniature soldering iron. With the temperature display and the control circuitry integrated into the grip, it makes soldering an even more fun and seamless experience. 90003 90020 90021 90217 90023 90021 90220 90023 90027 90002 Ditch your heavy soldering irons for this miniature one! 90003 90016 5. Work with a Good PCB Assembly House 90019 90002 If hand soldering and sourcing for your own components is too much of a hassle, or if you think working with tiny components is beyond the abilities of your mere mortal eyes, there is always the option of working with a professional PCB assembly house who are experienced and familiar with the pitfalls of PCB assembly.With 10 years of industry experience, Seeed's Fusion PCB assembly (PCBA) service is able to rapidly source components and assemble a complete board for you. 90003 90002 That is all we have for now. Have a badly butchered solder joint that you would like to share? Share them in the comments section below! 90003 90231 90002 Please follow and like us: 90003 90234 Continue Reading 90235 .