In this study, we developed a scratch dies, which is a three - stage filter automation device, which can completely remove foreign substances so that heavy metals are not detected. The primary filter is a cylinder that melts and transports recycled plastic, the secondary filter in the center screw device, and the tertiary filter in the nozzle part. The content of heavy metals in the recycled plastic raw materials before and after the development of the scratch dies was measured and compared. We want to ensure the environmentally friendly recycling of plastics and the safety of plastic recycled products.