SMT material throwing is usually called material throwing, that is to say, after the suction nozzle of the mounter picks up the material in the material tray, the material is thrown out in the process of moving to the PCB mounting position. Generally, the reason for this problem is that the suction nozzle pressure is not enough or the suction cup is damaged or the suction cup has dirt, etc. How to reduce the material throwing rate in smt processing is a problem worthy of attention for most SMT processing plants, because material throwing will affect the production efficiency, which will further affect the production cost.
In fact, the material throwing rate in SMT process is that the mounter throws the material into the throwing box or other places or does not absorb the material directly after absorbing the material in the process of SMT processing. Material throwing will cause excessive material loss, thus prolonging production time and reducing production efficiency. The production efficiency is directly related to the production cost, so every SMD factory will seriously reduce the throwing rate.
Generally speaking, the reasons for the high throwing rate are as follows:
First, the deformation, blockage and damage of the suction nozzle will result in insufficient air pressure, air leakage, which will lead to the situation that the material can’t be absorbed, the material can’t be taken correctly or the material can’t be recognized and thrown. This problem can be solved by changing the suction nozzle in time.
Second, the material taking position If the material taking position is not in the center of the material or the material taking height is not correct, the material taking will be discarded by the recognition system as invalid material, so the material taking position should be adjusted in the process of smt chip processing.
3. Contaminants on the vision and laser lens of the identification system interfere with the identification, improper selection of the identification light source, insufficient intensity and gray scale, damage to the identification system, etc., all of which will lead to an increase in the throwing rate. This problem can be solved by cleaning and wiping the surface of the identification system, adjusting the intensity and gray scale, and repairing or replacing the identification system.
IV. If the air pressure of vacuum is insufficient, it may cause unsmooth passage of vacuum trachea, which may lead to unsuccessful material taking or falling off on the way to sticking after picking up. Therefore, if there is leakage in smt chip processing, it is necessary to repair it in time, clean up the blockage, and adjust the air pressure as required.
