自動(dòng)點(diǎn)膠機(jī)使用的注意事項(xiàng)，在使用中會(huì)出現(xiàn)工藝缺陷：膠點(diǎn)大小不合格、針頭大小、針頭與PCB板間的距離、膠水溫度、膠水的粘度、拉絲、膠水浸染焊盤、固化強(qiáng)度不好易掉片等。解決這些問題應(yīng)整體研究各項(xiàng)技術(shù)工藝參數(shù)，從而找到解決問題的辦法。
Precautions for the use of automatic dispensing machine, there will be process defects in use: unqualified glue point size, needle size, distance between needle and PCB board, glue temperature, glue viscosity, wire drawing, glue dip pad, poor curing strength, easy to drop pieces, etc. To solve these problems, it is necessary to study the technical parameters as a whole, so as to find a solution.
1．點(diǎn)膠量的大小
1. The amount of dispensing

根據(jù)工作經(jīng)驗(yàn)，膠點(diǎn)直徑的大小應(yīng)為焊盤間距的一半，貼片后膠點(diǎn)直徑應(yīng)為膠點(diǎn)直徑的1.5倍。這樣就可以保證有充足的膠水來粘結(jié)元件又避免過多膠水浸染焊盤。點(diǎn)膠量多少由螺旋泵的旋轉(zhuǎn)時(shí)間長短來決定，實(shí)際中應(yīng)根據(jù)生產(chǎn)情況（室溫、膠水的粘性等）選擇泵的旋轉(zhuǎn)時(shí)間。
According to the working experience, the size of the glue spot diameter should be half of the pad spacing, and the glue spot diameter after the chip is pasted should be 1.5 times of the glue spot diameter. In this way, enough glue can be used to bond the components and too much glue can be avoided to contaminate the pad. The amount of dispensing depends on the rotation time of the screw pump. In practice, the rotation time of the pump should be selected according to the production situation (room temperature, glue viscosity, etc.).
2．點(diǎn)膠壓力（背壓）
2. Dispensing pressure (back pressure)
目前所用點(diǎn)膠機(jī)采用螺旋泵供給點(diǎn)膠針頭膠管采取一個(gè)壓力來保證足夠膠水供給螺旋泵。背壓壓力太大易造成膠溢出、膠量過多；壓力太小則會(huì)出現(xiàn)點(diǎn)膠斷續(xù)現(xiàn)象，漏點(diǎn)，從而造成缺陷。應(yīng)根據(jù)同品質(zhì)的膠水、工作環(huán)境溫度來選擇壓力。環(huán)境溫度高則會(huì)使膠水粘度變小、流動(dòng)性變好，這時(shí)需調(diào)低背壓就可保證膠水的供給，反之亦然。
At present, the dispensing machine adopts screw pump to supply the dispensing needle, and the rubber tube adopts a pressure to ensure enough glue to supply screw pump. If the back pressure is too high, it is easy to cause glue overflow and too much glue; if the pressure is too low, it will cause intermittent dispensing and leakage, resulting in defects. The pressure should be selected according to the same quality glue and working environment temperature. When the ambient temperature is high, the viscosity of glue will be reduced and the fluidity will be improved. At this time, the back pressure should be lowered to ensure the supply of glue, and vice versa.
3．針頭大小
3. Needle size
在工作實(shí)際中，針頭內(nèi)徑大小應(yīng)為點(diǎn)膠膠點(diǎn)直徑的1/2，點(diǎn)膠過程中，應(yīng)根據(jù)PCB上焊盤大小來選取點(diǎn)膠針頭：如0805和1206的焊盤大小相差不大，可以選取同一種針頭，但是對(duì)于相差懸殊的焊盤就要選取不同針頭，這樣既可以保證膠點(diǎn)質(zhì)量，又可以提高生產(chǎn)效率。
In the actual work, the inner diameter of the needle should be 1 / 2 of the diameter of the dispensing point. In the dispensing process, the dispensing needle should be selected according to the size of the pad on the PCB: for example, the pad sizes of 0805 and 1206 are similar, so the same kind of needle can be selected, but different needles should be selected for the pad with great difference, which can not only ensure the quality of the dispensing point, but also improve the production efficiency.
4．針頭與PCB板間的距離
4. Distance between needle and PCB
不同的點(diǎn)膠機(jī)采用不同的針頭，有些針頭有一定的止動(dòng)度（如CAM/A LOT 5000）。每次工作開始應(yīng)做針頭與PCB距離的校準(zhǔn)，即Z軸高度校準(zhǔn)。
Different dispensers use different needles, some of which have a certain degree of stop (such as cam / a lot 5000). The distance between the needle and PCB should be calibrated at the beginning of each work, that is z-axis height calibration.
5．膠水溫度
5. Glue temperature
一般環(huán)氧樹脂膠水應(yīng)保存在0--5℃的冰箱中，使用時(shí)應(yīng)提前1/2小時(shí)拿出，使膠水充分與工作溫度相符合。膠水的使用溫度應(yīng)為23℃--25℃；環(huán)境溫度對(duì)膠水的粘度影響很大，溫度過低則會(huì)膠點(diǎn)變小，出現(xiàn)拉絲現(xiàn)象。環(huán)境溫度相差5℃，會(huì)造成50％點(diǎn)膠量變化。因而對(duì)于環(huán)境溫度應(yīng)加以控制。同時(shí)環(huán)境的溫度也應(yīng)該給予保證，濕度小膠點(diǎn)易變干，影響粘結(jié)力。
Generally, the epoxy resin glue should be kept in the refrigerator at 0-5 ℃, and should be taken out 1 / 2 hour in advance to make the glue fully conform to the working temperature. The use temperature of glue should be 23 ℃ -- 25 ℃; the ambient temperature has a great influence on the viscosity of glue. If the temperature is too low, the glue point will become smaller and wire drawing phenomenon will appear. The environmental temperature difference of 5 ℃ will cause the change of 50% dispensing amount. Therefore, the ambient temperature should be controlled. At the same time, the temperature of the environment should also be guaranteed, the humidity is small, the adhesive point is easy to dry, affecting the adhesion.
6．膠水的粘度
6. Viscosity of glue
膠的粘度直接影響點(diǎn)膠的質(zhì)量。粘度大，則膠點(diǎn)會(huì)變小，甚至拉絲；粘度小，膠點(diǎn)會(huì)變大，進(jìn)而可能滲染焊盤。點(diǎn)膠過程中，應(yīng)對(duì)不同粘度的膠水，選取合理的背壓和點(diǎn)膠速度。
The viscosity of glue directly affects the quality of dispensing. If the viscosity is high, the adhesive point will become smaller, even wire drawing; if the viscosity is low, the adhesive point will become larger, and then the pad may be stained. In the dispensing process, the reasonable back pressure and dispensing speed should be selected for different viscosities of glue.
7．固化溫度曲線
7. Curing temperature curve
對(duì)于膠水的固化，一般生產(chǎn)廠家已給出溫度曲線。在實(shí)際應(yīng)盡可能采用較高溫度來固化，使膠水固化后有足夠強(qiáng)度。
For the curing of glue, the general manufacturers have given the temperature curve. In practice, it should be cured at a higher temperature as far as possible, so that the glue has enough strength after curing.