手工焊接培訓教材(7)ppt課件

1、EET 3124 Soldering 焊接Elements of Project Design, Analysis and Fabrication by Machine MethodsPCB Soldering 電子線路板焊接wRead Chapter 17wSoldering alloying between solder and the metal parts between which an electrical connection is formed.Soldering Methods焊接方法wSeveral Methods of SolderingwHand 手工焊接wDip浸焊w

2、Wave波峰焊接wInfrared Re-flow 紅外線回流焊接wVapor Phase 熱風回流焊接Solder Composition 焊料wSolder used in electronics is an alloy of tin and lead. 電子產(chǎn)品焊料是錫鉛合金。wThe amount of tin ranges from 50 to 70%.錫所占比例為50% 到70%。wThe ratio determines the strength, hardness and melting point of the solder.w錫所占比例決議焊點的強度、硬度和熔點。Solde

3、r Melting Point Graph熔點固體形狀液體形狀熔融形狀Solder Composition Cont.焊料wThe most common tin/lead ratio is 60/40.最常見錫鉛比例為60/40。wEutectic solder has a tin/lead ratio of 63/37 and has almost no plastic transition state.共晶焊錫之錫鉛比例為63/37，幾乎沒有熔融形狀。wDifferent ratios can be selected based on specific needs.根據(jù)需求可選擇不同比例

4、。Solder Alloying 焊接合金wWhen solder melts onto a PCB connection, a thin film of metal is dissolved from the copper surface. 當焊錫在PCB焊盤上融化時，銅金屬外表會有一層薄膜融解；wThis copper/solder mixture forms an alloy and establishes an electrically continuous joint.這個銅/焊錫構(gòu)成合金并成為穩(wěn)定的電氣銜接。Solder Forms 焊錫外形wSolder is available

5、 in the following forms:wWire spools 錫絲軸裝wBars錫條wSheets錫片wPellets錫球wWasher and other specialized shapesw錫制墊片及其它特殊外形Solder Forms Cont.焊錫外形wFor hand soldering, wire solder comes in ranges of 0.030 to 0.090 in diameter. 對于手工焊接，焊錫絲直徑介于0.030 to 0.090 0.762 mm to 2.286 mm wMost solder wire is available wi

6、th a core containing flux. 多數(shù)焊錫絲均有內(nèi)孔Flux 助焊劑wFlux is used to remove oxidation from the surface to be soldered.w助焊劑用于除去焊接外表的氧化物。wThe flux removes the oxides from the metal surface and suspends them in solution where they float to the surface during the soldering process.w助焊劑除去金屬外表的氧化物，并在焊接過程w中將之移至焊點外

7、表。Flux Cont. 助焊劑wFlux is corrosive and if left on the surface of the PCB, will deteriorate the conductor surfaces and reduce the resistance of the insulation between soldered connections.w助焊劑具有腐蝕性，殘留在PCB外表會使導(dǎo)體蛻變，并降低焊點間的絕緣性能。wThis corrosive action can also damage components.w助焊劑腐蝕性對元器件也有危害。Flux Cont.

8、助焊劑wThere are three major classifications of flux:wChloride (inorganic salts)氯化物 無機鹽wOrganic (acids and bases)有機物wRosin松香/樹脂wChloride and Organic fluxes are highly reactive at room temperature and are therefore not recommended for use in electronic construction.w氯化物、有機物助焊劑在室溫下活性很強，普通不w用于電子產(chǎn)品制造。Flux

9、Cont.助焊劑wRosin core fluxes are used almost exclusively for electronic construction.w松香基助焊劑大多公用于電子產(chǎn)品制造。wRosin core fluxes are non-corrosive at room temperature.w松香基助焊劑在室溫下沒有腐蝕性。wRosin core fluxes are corrosive at soldering temperatures.w松香基助焊劑在焊接溫度下具有腐蝕性。Flux Application 助焊劑運用wLiquid flux can be appl

10、ied by:wWiping 擦拭wDipping 浸漬wSpraying 噴霧wSponging 用海綿揩拭wFoaming 發(fā)泡Flux Application Cont.助焊劑運用wPaste flux can be applied by:wWiping 擦拭wBrushing 刷wRosin core solder uses flux that melts upon heat application during the soldering process.Flux Removal 去除助焊劑wAfter the soldering process is complete, the f

11、lux must be removedwImproves appearance w改善外觀wEliminates possible corrosion problemsw防止能夠的腐蝕問題wLess chance of electrical leakagew減少漏電時機Flux Removal Cont.去除助焊劑wSome techniques for flux removal are:wUse of flux remover sprays w助焊劑清洗劑wBrushing with denatured alcoholw用非飲用酒精刷洗wDipping PCB assembly into a

12、 solvent solutionw將PCBA浸入清洗液wUltrasonic equipment 超聲波清洗設(shè)備The Soldering Iron 烙鐵wThe soldering iron consists of 4 basic parts:wTip 烙鐵頭wHeating Element 加熱單元wHandle 手柄wPower Cord 電源線The Soldering Iron Cont.烙鐵wSoldering irons are selected based on:wSize and style of tipw尺寸和烙鐵頭外形wTip materialw烙鐵頭資料wRequir

13、ed tip temperature w要求的烙鐵頭溫度wTip temperature recovery time.w烙鐵頭溫度恢復(fù)時間Tip Selection烙鐵頭選擇wSoldering iron tips come in many styles.wTips are selected on the basis of personal preference and the goal of providing the largest contact area to the area to be soldered while minimizing the possibility of hea

14、t damage to surrounding leads and components.w烙鐵頭選擇根據(jù)焊盤大小、零件大小、焊接溫度、元器件對溫度的敏感性、個人喜好等。Tip Types烙鐵頭外形wChisel & Pyramid Used for hand wiring and general repair work. Allows large areas to be heated rapidly.w鑿子、棱椎形用于線材焊接和普通的修繕任務(wù)。可以使較大區(qū)域迅速加熱。wBevel Used for soldering terminal pad connections on singl

15、e sided boards.w斜角形用語焊接單面板上的接線端焊盤。Tip Types Cont.烙鐵頭外形wConical Used for high density wiring and heat sensitive parts.w圓錐形用語焊接微小間距和溫度敏感元器件。wRadius Groove - Used on round components.w半凹槽形用語圓形器件。Tip Types Cont. 烙鐵頭外形Soldering Iron Temperature烙鐵溫度wA tip temperature of 600 to 900 degrees F is sufficient

16、for general purpose soldering.w烙鐵頭溫度600到900華氏度316到482攝氏度可以足夠滿足普通的焊接需求。wSoldering irons are rated in watts. They are typically available from 15 to 60 Watts.w烙鐵功率普通為15到60瓦。Soldering Iron Temperature Versus Wattage烙鐵溫度/功率Soldering Iron Tip Color Versus Temperature烙鐵頭顏色/溫度Hand Soldering 手工焊接wBoards mus

17、t be clean to begin with, especially if theyre not previously tinned with solder. Clean the copper tracks using e.g. an abrasive rubber block and clean with denatured alcohol.w首先必需保證PCB干凈，特別是沒有預(yù)鍍錫的板?？梢赃\用橡膠擦子或者非飲用酒精清潔PCB。Hand Soldering手工焊接Hand Soldering手工焊接wClean the iron bit (tip) using a damp spong

18、e. Iron featured is an Ungar Concept 2100 Soldering Station. 運用潮濕海綿清潔烙鐵頭。Hand Soldering手工焊接wInsert components and bend the leads so that the part is held in place. w插入元件，將w管腳折彎以固定w元件。Hand Soldering 手工焊接wIts usually best to snip the wires to length prior to soldering. This helps prevent transmitting

19、mechanical shocks to the copper foil. w通常最好的做法是w提早將零件腳剪至w需求的長度。w這可以預(yù)防對銅箔w的機械沖擊。Hand Soldering 手工焊接wApply a clean iron tip to the copper and the lead, in order to heat both items at the same time. w務(wù)必堅持烙鐵頭w干凈，并同時接觸w加熱元件腳和焊盤。Hand Soldering 手工焊接wContinue heating and apply a small amount of solder. Remo

20、ve the iron and allow the solder joint to cool naturally.w繼續(xù)加熱，并放入w少量錫絲。移開烙鐵w以使焊點自然冷卻。Hand Soldering 手工焊接wIt only takes a second or two, to make the perfect joint, which should be nice and shiny.w只須12秒鐘焊點w就可以構(gòu)成。w良好的焊點應(yīng)該w整潔亮堂。 Solder Defects 焊接缺陷wSolder Peaking - Sharp point of solder protruding from

21、 a connection.wRapid removal of heat prior to solder becoming completely melted to liquid stage.w錫尖w在焊錫未完全熔化成為液體形狀之前快速移開烙鐵所致。Solder Defects Cont.焊接缺陷wIncomplete wetting Alloying process not completed.w未潤焊合金過程未完成wUsually the result of insufficient heat and/or solder. w通常由加熱缺乏或者焊錫缺乏導(dǎo)致。wMay also occur

22、if contamination is on the terminal pad or soldering iron tip.w也能夠由于焊盤或者烙鐵頭污染所致。Solder Defects Cont.焊接缺陷wExcessive solder lead contour not completely visible. 多錫包焊- 元件腳周線不可見。wReduce the amount of solder appliedw減少用錫量wCold solder joint dull-gray, grainy appearance.w冷焊錫點呈暗灰色，外表粗糙。wResult of insufficie

23、nt heat.w加熱溫度缺乏導(dǎo)致。Solder Defects焊接缺陷wAn example of a dry joint - the solder failed to flow, and instead beaded to form globules around the wire. Solder Defects Cont.焊接缺陷wTenfold excess of solder, and (extreme left) incomplete joint with poor coverage. There is no need to add more solder for luck. So

24、lder Defects Cont.焊接缺陷wOne example of several dry joints found within a commercial PSU adaptor for a computer peripheral. Solder Defects Cont.焊接缺陷wA close-up reveals the terrible standard of soldering (and quality control), with a fracture visible on this ground/ earth joint. De-soldering PCBs 去錫解除焊

25、接wSeveral aids to use for de-solderingwSolder wick 吸錫芯繩wSolder sucker吸錫器wDe-soldering bulb 去錫燈泡wDe-soldering tips 去錫尖頭wExtraction Tools 抽吸工具wVacuum de-soldering station 真空去錫任務(wù)臺De-soldering去錫wThe two solder joints to be de-soldered, to enable a faulty component to be removed. De-soldering Cont.去錫wIf

26、using a de-soldering pump, apply the iron first to melt the solder (1-2 seconds). w假設(shè)運用吸錫器，w先用烙鐵使w錫熔化。w12秒De-soldering Cont.去錫wThe nozzle of the de-soldering pump is applied to the molten solder and the spring-loaded plunger is then released, drawing the solder up into the pump. Repeat if needed. w吸

27、錫器吸嘴對準熔化的焊錫，釋放彈簧活塞w，吸走焊錫。可反復(fù)進展。De-soldering Cont.去錫De-soldering Cont.去錫wThe first joint, now de-soldered. The second joint will be de-soldered using braid.De-soldering Cont.去錫wSelect a suitable width of braid編織, and press it down onto the COLD joint using the hot tip of the iron. De-soldering Cont.去

28、錫wMolten solder is drawn up by capillary action into the braid. Care not to overheat, or drag whiskers of solder over the board, nor let the braid solidify on the joint! w毛細管吸附作用De-soldering Cont.去錫De-soldering Cont.去錫wThe component dropped out of the board after de-soldering. Sometimes, it may need

29、 persuading with pliers 鉗子. De-soldering Cont.去錫wClose-up shot of both joints, now de-soldered and ready for the replacement part to be fitted. Dip Soldering 浸焊wPCB is physically dipped into a molten pot of solder.wBoard is cleaned and then fluxed prior to dipping.wPCB預(yù)先上助焊劑。wUsually dipped by hand.Solder Pot Examples 錫爐Wave Soldering 波峰焊接wA conveyor syst