How to Improve the Precision of Plastic Mold
For the injection mold, the precision of plastic parts is grade 3 and 3a, the weight is 5g, the hardened gating system is used, and the number of cavities is 4-6; The plastic parts are of general accuracy (4-5 levels), the molding materials are locally crystalline materials, and the number of cavities can be 16-20; The weight of plastic parts is 12-16g, and the number of cavities is 8-12; For plastic parts with a weight of 50-g, the number of cavities is 4-8. For amorphous plastic parts, the recommended number of cavities is 24-48, 16-32 and 6-10. When we continue to increase the weight of plastic parts, we rarely use multi cavity molds. For plastic parts with 7-9 accuracy, the maximum number of cavities is 50% more than that of plastics with 4-5 accuracy.
2. Determine the parting surface. The position of parting surface shall be conducive to mold processing, exhaust, demoulding and molding operations, and the surface quality of plastic parts.
3. Determine the pouring system (shape, position and size of main runner, runner and gate) and exhaust system (method of exhaust, position and size of exhaust slot).
4. Select the ejection method (ejector rod, pipe jacking, push plate, combined ejection), and determine the side concave treatment method and core pulling method.
5. Determine the cooling and heating methods, the shape and position of the heating and cooling groove, and the installation position of the heating element.
6. According to die material, strength calculation or empirical data, determine the thickness and overall dimensions of die parts, the overall structure and the positions of all connections, positioning and guide pieces.
7. Determine the structural form of main molding parts and structural parts.
8. Considering the strength of each part of the mold, calculate the working dimensions of the molded parts.
If these problems are solved, the structural form of the mold will be solved naturally. At this time, we should draw the mold structure sketch by hand to prepare for the formal drawing.
