In the high-tech electronic era, the current situation of product diversification, so that the application of precision dispensing machine is more and more widely. Manufacturers in the use of precision dispensing machine production, in the production process will still encounter a variety of large and small dispensing problems. Here is ADTECH to tell you the common problems and solutions of dispensing control system process?
1, dispensing control system components offset;
Phenomenon: solidified component shift, serious component pin is not on the pad.
Causes: patch glue amount is not uniform (such as chip components two point glue one more and one less), patch component displacement, patch adhesive force decline, PCB placement time is too long after glue semi-curing.
Solution: check whether the rubber nozzle is blocked, eliminate the phenomenon of uneven glue; The PCB placement time should not be too long (less than 4h) after adjusting the working state of the SMT machine, changing the glue and dispensing.
2. The pin of the dispensing control system floats/shifts after curing;
Phenomenon: After curing, the component pin floats or shifts, and the tin material will enter the solder plate after wave soldering, and short circuit and open circuit will occur in serious cases.
Cause: patch glue is not uniform, patch glue amount is too much, patch element offset.
Solution: adjust the dispensing process parameters, control the dispensing amount, adjust the patch process parameters.
3, glue control system drawing/trailing;
Phenomenon: Common defects in wire drawing/trailing and dispensing.
Causes: the inner diameter of the glue nozzle is too small, the dispensing pressure is too high, the spacing between the glue nozzle and PCB is too large, the adhesive expires or is of poor quality, the adhesive degree is too high, the adhesive fails to return to room temperature after being removed from the refrigerator, and the dispensing amount is too much, etc.
Solution: change the nozzle with larger inner diameter, reduce the dispensing pressure, adjust the "stop" height, change the glue, select the glue suitable for viscosity, remove from the refrigerator should be restored to room temperature (about 4h), adjust the dispensing amount.
4. The nozzle of the dispensing control system is blocked;
Phenomenon: the amount of the glue nozzle is less than the glue point.
Cause: The pinhole is not completely cleaned, the patch glue is mixed with impurities, the hole blocking phenomenon, and the incompatible glue is mixed.
Solution: change the clean needle, change the quality of better patch glue, patch glue brand should not be mistaken.
5, dispensing control system air play;
Phenomenon: only glue action, no glue amount.
Cause: Mixed with bubbles, rubber nozzle blockage.
Solution: the glue in the injection cylinder should be debubbled (especially the glue loaded by oneself), according to the glue nozzle blockage method.
6, after the glue control system is cured, the component bond strength is not enough, and the wave peak will fall off after welding;
Phenomenon: After curing, the bond strength of the component is not enough, which is lower than the standard value. Sometimes the chip will fall off when touched by hand.
Cause: after curing process parameters are not in place, especially the temperature is not enough; Component size is too large, heat absorption, light curing lamp aging, glue is not enough, component/PCB contamination.
Solution: adjust the curing curve, especially to increase the curing temperature, usually the peak curing temperature of hot curing glue is very key, reach the peak temperature is easy to cause flake drop. For light curing glue, we should observe whether the light curing lamp is aging, whether there is blackening of the lamp tube, the number of glue, whether there is pollution of components/PCB.
The above is for dispensing control system process common problems and solutions, only for your reference.