The quality of the self-made ejector is better, but the processing cost is too high. Now, standard parts are generally used, and the quality is poor. If the gap between the ejector pin and the hole is too large, there will be leakage, but if the gap is too small, the ejector pin will be stuck due to the increase of mold temperature during injection. What's more dangerous is that sometimes the ejector pin is pushed out of the normal distance and will not move and break. As a result, the exposed ejector pin cannot be reset and the die will be damaged when the mold is closed next time. In order to solve this problem, the ejector rod is re-ground, retaining a 10-15mm mating section at the front end of the ejector rod, and grinding the middle part down by 0.2mm. After all ejector rods are assembled, the matching clearance must be strictly checked, generally within 0.05~0.08 mm, to ensure that the entire ejector mechanism can advance and retreat freely.