Dividing of metal and plastic components of printed circuit boards

Abstract

This paper contents one possibility of PCB separation due to the temperature due to the different thermal expansion of the metal path and the plastic from which the boards are made. Using the knowledge from the literary study and the simulation environments used, we have reached the maximum analysis of the problem. The separation of metal and plastic may occur due to temperature changes if the temperature difference is sufficient. We have carried out a study of printed circuit board production so we can choose the appropriate path of separation. Furthermore, we calculated the shear stress size required to tear the conductive copper paths from the epoxy resin. The temperature field in a two-layer board was modeled in the FEMLAB and Pro/ENGINEER programming environments. From the simulated temperature field simulations, conclusions can be drawn that accurately describe the condition and characteristics of materials subjected to heat shock. They derived the resulting relationship for calculating the resulting shear stress needed to separate the conductive paths and plastic materials of the PCB. In our own experiments, we used several ways to heat PCBs. The temperature is also sufficient for the separation of tin. After using the mechanical separation of the components, they were dropped from the PCB. Mechanical separation was also used when removing conductive paths. This separation is effective, but in the newer types of PCBs, the cyclical effects of thermal shock have to be applied to the separation of copper paths. Laboratory tests have demonstrated the viability of the proposed solution. The proposed method of recycling could lead to industrial use, which requires consistent sorting of waste electrical and electronic equipment. © The Authors, published by EDP Sciences, 2017.