1, Parting surface (Parting line) In order to remove the plastic injection product from the mold, the plastic injection mold must be divided into two parts, the interface is called the parting surface. It has the function of parting mold and exhaust gas, but because of the difference of mold accuracy and molding, it is easy to produce burring, joining line, affecting the appearance and accuracy. 
Note when designing parting surface: 1. It shall not be located in an obvious position and affect the appearance of the plastic product. When the mold is opened, the product should be left on the side with the release structure. 2. Located in the mold processing and product processing easy place. For plastic products with high coaxiality requirements, the cavity is designed on the same side as far as possible. 3. Avoid long core-pulling, consider placing it in the direction of opening the mold, if necessary, the core-pulling mechanism should be located on the side of the mold as far as possible. 4. Generally do not use arc part parting, which will affect the appearance of the product. 5. For the plastic with good fluidity and easy overflow edge, the splicing method should be used to prevent the generation of rough edges. 6. For products with high height and small demoulding inclination, it is advisable to split the mold in the middle and divide the cavity on both sides to facilitate the demoulding.
2, Draft Angle In order to make the product easily out of the mold, the product surface must have a draft Angle. Its size depends on the shape of the product, the structure of the plastic injection molding, the surface accuracy and the processing method. Generally 1-3°, without affecting the appearance and performance of the product, the larger the draft Angle, the better.
