Study to Improve the Powder Residue on the Depanelized Printed Circuit Board in Surface Mount Technology Process

Printed circuit board is very common in everyday life. However, in response to environmental regulations in recent years, there are problems such like difficult machining due to the addition of inorganic fillers to enhance the rigidity, tool wear increasing caused the size of the product earlier exceeded the control limit, and the powder accumulation during machining is harmful to the subsequent process. In order to improve the above problems of powder accumulation, this research focus on the tool wear and chip forms in the composite material machining, and find the relevance to improve powder accumulation. Firstly, analyze the factors of powder formation, and then to suppress and to improve it. Through machining experiments, it show that the composite material properties, machining parameters, and tool wear during machining have relevance with powder accumulation. Talking about the two levels discussed above, one is the material properties and processing conditions, which is difficult to control and it is not discussed due to the difference of characteristics of the product with the difference of materials and different firms; the other is tool wear, which is possible to experiment on and to improve. About the problem of tool wear, the coating which has been chosen is diamond-like carbon, which has excellent wear resistance, low friction coefficient and less adhesion on the surface. After cutting 5 panels, the experiment result shows that the replacement for the coating can improve the accumulation of powder on about 26 percent than the original ZrN result of coating. This research also use a designed mask to cover the tool, and supply the high-pressure air in order to raise the removal rate of cutting chips. Experimental results show that using this device can effectively improve the tool wear and dust accumulation. After cutting 5 panels, using the mask with blowing can improve the accumulation of powder on about 44 percent than the original condition. If the blowing change into inhale, it is able to improve the situation on about 27 percent than the original condition. In the test of the usage of air mask with blowing and changing of coating, after cutting 5 panels, choose a suitable coating can improve the accumulation of powder on about 56 percent than the original condition. According to the prediction of the experiment, the replacement of the diamond-like carbon coating and the usage of air mask with blowing may be processing the original 35 meters to raise the ceiling to about 130 meters.