A、焊接原理
The principle of soldering:
電源通過(guò)輸出電流加熱電極和工件，電極傳熱給工件，工件達(dá)到一定的溫度時(shí)預(yù)置于焊接位置的焊錫熔化，熔化后的焊錫通過(guò)毛細(xì)作用流入焊接接縫中，與鍍層發(fā)生擴(kuò)散與互相溶化，冷確后形成牢固的接頭。這里，加熱方式、加熱過(guò)程、焊接溫度、保溫時(shí)間、焊料與助焊劑等是影響焊接質(zhì)量的重要因素。
The power supply outputs current to heat the electrode and workpiece. As the workpiece temperature climbing to a certain value, the solder is pre-placed on the joint, and then the solder is melt and flows into the gap of joint with capillary action. The tin and plating layer will diffuse and compose each other. This forms a firm joint. In the whole process, there are many factors affecting the welding quality, such as the heating mode, heating duration, welding temperature, heating preservation time, the solder and flux to be used.
考慮到整個(gè)焊接過(guò)程方便、穩(wěn)定可靠，推薦采用帶溫度控制的熱壓焊加熱電源。加熱曲線如圖1所示。
Considering the convenience and stability, the hot pressure ( reflow) welding power supply is suggested. The whole heating curve can be shown in Fig.1.
圖中加熱的過(guò)程包括預(yù)升溫、預(yù)熱溫度保持（t1－t2），焊接升溫、焊接溫度保持和冷卻等階段?？梢酝ㄟ^(guò)調(diào)節(jié)溫度的上升速度V1、V2來(lái)保證工件的加熱速度符合焊接加熱規(guī)律需求，同時(shí)設(shè)置t1－t2、t3－t4的時(shí)間間隔來(lái)調(diào)節(jié)預(yù)熱階段和焊接階段的保溫時(shí)間、保證加熱均勻、接頭形成穩(wěn)定一致，隨后冷卻使焊料凝固，達(dá)到最佳的焊接效果。
The heating process includes five stages: temperature first up-sloop stage, pre-heating stage, welding temperature up-sloop, welding and cooling down. These keep the heating of the workpiece smoothly by adjustment of heating speed V1、V2 . At the same time, we can set the time of each stage to assure the welding quality.
B、主要構(gòu)成：
Composition
電源
Power supply
采用熱壓焊類型的直流輸出的逆變電源。逆變頻率1kHz。電源基本參數(shù)如下：
The inverter similar as hot pressure welding is adopted. The inverting frequency is 1 kHz. The main parameters are as following:
額定功率：4kVA 或7kVA
Rated power: 7kVA or 4kVA
負(fù)載持續(xù)率：50％
Duty cycle: 50%
各階段溫度控制范圍：50－600℃
Temperature setting range: 50～600℃
溫度控制誤差：≤±5℃
Error of temperature: ≤±5℃
預(yù)熱時(shí)間：0.1-10s
Warm-up time: 0.1-10s
焊接保溫時(shí)間：0.1-10s
Heating-maintain time: 0.1-10s
升溫速度：20－200℃/s
Calefactive rapidity: 20－200℃/s
溫度校正設(shè)定
Temperature adjustment
電極（帶熱電偶測(cè)量）
Electrode (measurement with thermocuple)
電極材料擬用鈦合金，并嘗試采用銅合金，最后通過(guò)試驗(yàn)決定。電極形狀尺寸依據(jù)工件設(shè)計(jì)。熱電偶設(shè)在電極前端靠工件的部位。
The material of the electrode will be confirmed by the experiment. The titanium alloy or copper alloy is no bad material. The shape of electrode is designed basing on the workpiece. The thermocouple will be placed in the electrode forepart near the workpiece.
C、具備性能特點(diǎn)
Performance and characteristic
電源響應(yīng)快，溫度曲線平穩(wěn)
Response rapidly, balanced temperature curve.
逆變電源時(shí)間調(diào)節(jié)分辨率可達(dá)1ms（1kHz逆變頻率），相對(duì)工頻交流電源的20ms（50Hz），反饋控制周期大大縮短，可以將溫度控制得更加平穩(wěn)、準(zhǔn)確。直流輸出也使得熱效率提高，溫度波動(dòng)小。
The controlling cycle is 1 ms with the 1 kHz invert frequency. It is the 1/20 of industry frequency welding power supply. The control precision is improved remarkably. It supplies the chance to controlling the temperature exactly.
零件溫升的影響小，焊接質(zhì)量好.
The effect of the workpiece temperture rising is little, high welding quality.
升溫、保溫分階段精確控制，確保工件熱平衡，避免工件過(guò)熱，抑制對(duì)元器件的影響，同時(shí)也保證焊接質(zhì)量穩(wěn)定可靠。
The warm-up stage and heating-maintaining stage is divided in the heating process. So it ensures the heating balance and avoids the over-heating. It brings the high quality product.
溫度顯示功能
Temperature display
焊接溫度面板實(shí)時(shí)顯示?？紤]到熱電偶檢測(cè)溫度與焊接節(jié)點(diǎn)溫度存在偏差，該系統(tǒng)提供溫度校準(zhǔn)功能，確保實(shí)時(shí)顯示較準(zhǔn)確的焊接接頭處的溫度。
The temperature of welding is real time displayed. As the temperature of the point detected by the thermocouple and welding point is different, the temperature adjustment part is included in this system to assure the veracity of the welding point temperature.
電極保護(hù)
Electrode protection
針對(duì)目前所使用電極易氧化，需經(jīng)常維修的狀況，該方案所提供的電源有利于克服目前方法易產(chǎn)生過(guò)熱而損傷電極的缺點(diǎn)，減少電極維護(hù)次數(shù)，同時(shí)也延長(zhǎng)了電極的使用壽命。
The power supply in this project avoids the shortcoming of electrode abrasion brought by the over-heating. So it reduce the maintain time and extend the duration.
