What is the hemming process of the heat sink graphite sheet

A:
Now many electronic products need to use thermal graphite sheets for heat dissipation, which has been widely used in the smart phone industry. The hemming process of thermal graphite sheets is a headache for manufacturers. Currently, there are thermal graphite sheets used in the market. Two-knife, three-knife and four-knife.
The radiating graphite sheet edging can prevent the occurrence of graphite gradation, but at the same time, the processing process is very complicated. Generally, two die-cutting processes are required according to the structure of the product. The film must be silicone. Once the acrylic adhesive is attached, it is difficult to peel it off. The two sides of the silicone protective film are pasted with more than 0.075 PET. The main function is to turn the positioning hole to the other side and paste graphite in the middle. I punched the graphite half-length to remove the shape waste and then stuck the PET substrate glue. The width of the glue must cover the PET on both sides, but cannot cover the holes, and then remove the silicone protective film on the reverse side, and stick the PET substrate tape on the other side. The whole process is completed by two sets of punching.