Analysis of the main reasons and solutions for injection mold sticking?


Author: MULAN -Plastic Molding Manufacturer

During the production process of injection mold processing, various problems are often encountered, which lead to the finished molds not up to standard, such as the surface of the mold product is not smooth, the color is wrong, the color difference is serious, etc., and the sticking of the injection mold will also cause the mold product to be unsatisfactory. Qualified, what is the main reason for the stickiness of the injection mold? Today, Mulan injection mold processing manufacturer will tell you about the causes and solutions of injection mold sticking! 1. Reasons for injection mold sticking 1. Mold reasons (1) The inner wall of the mold cavity is not smooth. There are surface defects such as chisel lines, nicks, scars, and depressions in the mold cavity and flow channels, which will cause mold cavity holes. The cavity or the inner wall of the rib is not smooth, and the injection molded part has too much demoulding resistance to cause mold sticking; this situation can be improved by polishing the inside of the mold sticking mold cavity. The filling direction of the molten material is consistent. (2) The gap at the scratched part of the mold is too large. When the melt produces flash in the scratched part of the mold or in the gap of the insert, it will also cause difficulty in demoulding. In this regard, the damaged part should be repaired and the insert gap should be reduced.

2. Process reasons The injection molding process setting is unreasonable, so that the product sticks to the mold in the cavity, the place where the mold sticks is moving, and it is possible to fix the mold; there are mainly the following two situations: (1) Injection pressure Injection pressure 1. The force is too large, and the injection time is too long, so that the molten resin is saturated and injected into the mold cavity, and the resistance is too large when the injection molded parts are demoulded, and some injection molded parts remain in the mold cavity; for injection molds The injection molding process is optimized, and the corresponding injection pressure, holding pressure, and injection molding time are reasonably adjusted; (2) Insufficient cooling The injection molded parts are not cooled sufficiently, and the injection molded parts have not been completely cooled and shaped when demoulding, and the injection molded parts are partially injected when the product is ejected Parts remain in the mold cavity; the cooling time of the cooling mold can be adjusted longer, and then slowly reduce the cooling time according to the production situation, and then make it fixed; Relatively low, the fluidity of the resin is poor or during debugging, the injection is insufficient to fill the mold cavity, and when the injection part is ejected, the incomplete product is unbalanced, resulting in sticking phenomenon; when starting up, when debugging the production part, It is better to adjust about 90% of the injection cavity; secondly, spray some release agent before starting the machine; especially where it is easy to stick to the mold; 2. The treatment method of the sticky mold of the injection mold 1. In the case of a large sticky product area , and the sticky mold product is not misplaced, you can manually close the mold again, or put a piece of thick towel paper, close it tightly and then open the mold to see if the product can be brought out; Pry out the surrounding parting surface; 3. For deep reinforcing ribs or holes, use a musket or gas to burn the plane strips, insert iron wires into the sticky mold and cool down and pull them out slowly; 4. Dismantle the mold cavity Disassemble the mold and carry out sticking treatment; 5. If there is a vacuum in the front mold when the mold is opened, the front mold should be equipped with an exhaust needle to eliminate the influence of the vacuum. Mold sticking of injection molding products is one of the common occurrences in the process of injection molding production. I hope the above solutions can help you to avoid sticking molds in the production of mold products.

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