With the improvement of technology and people's living level, people's requirement on electronic products have moved towards lightness, thinness, miniature, high performance and multiple functions so that miniature and integrity of electronic products have become the main direction of their development. In order to increase the density level of components, lots of single-side and double-side circuit boards primarily manifest surface mount components (SMCs) or surface mount devices (SMDs). However, in terms of intrinsic intensity, reliability and applicability, PIP components still hold more advantages than SMCs and SMDs in some cases, especially for edge connectors. For example, in double-side SMT (Surface Mount Technology) boards featuring mixed assembly with few PIP components on the top, application of PIP technology is helpful to process reduction and cost control. PIP technology is a printing method by template, that is, some amount of solder paste is printed on the surface of SMCs and on through holes and pads of through-hole mounted components. After the completion of mounting, soldering is completed after high-temperature oven.
Compared with traditional technology, PIP technology has the following advantages:
a. PCB fabrication and technology process is simplified owing to the absence of wave soldering.
b. Workshop space is saved due to fewer applications of needed equipment, material and workers.
d. High defect rate caused by wave soldering can be avoided so that first pass yield can be improved.
e. One or more heat treatment steps can be omitted so that PCB solderability and component reliability will rise.
f. Thru-hole reflow (THR) technology is capable of reducing the amount of flux, avoiding the contamination of flux on PCB caused by wave soldering.