Today, many rubber product manufacturers make it difficult to demold when they produce molded products. So why is it difficult to get out? How to prevent difficult demoulding?
First, let us understand the factors that limit the release of rubber products:
(1) The rubber product mold must be easy to demold when designing, must accurately conform to the contour and shape of the rubber product, the structure must be simple, reasonable, easy to operate and meet technical requirements;
(2) The mold should be maintained regularly, and observe its cleanliness, deformation, firm positioning and smooth surface.
2. Poor structure of rubber products. When designing rubber products, pay attention to their shape, thickness, and demolding slope, which is the main factor. When the product is removed from the oven, it will shrink concentrically due to the cooling of the product, which will create a large holding force on the core or pin, which hinders demolding. If the release slope increases, this resistance can be significantly reduced, and defects such as product tearing due to non-slope can be avoided. Generally, the product slope is between 1 ° and 3 °.
3. Irrational product formula, insufficient vulcanizing agent and accelerator in the formula, or unreasonable vulcanization temperature and time design, resulting in insufficient vulcanization; or too much rubber content in rubber raw materials, too much accelerator vulcanizing agent will also cause desorption Difficult.
4. Production process In the production process of rubber molded products, injection pressure, holding pressure, vulcanization temperature, vulcanization time, etc. will also affect the ease of demolding. For example, if the injection pressure is too high, it will cause elastic deformation of the mold parts and produce a pressing force. If the holding pressure is too high and the time is too long, it will also lead to an increase in the pressure in the cavity, resulting in large internal stress, which will cause deformation of the mold parts or flashing between the mating surfaces, which will make demoulding more difficult.
The second is the demolding method. By analyzing the demolding factors, the following methods can be used to avoid demolding difficulties or solve demolding difficulties.
1. The mold structure is reasonable, the rigidity of the mold should be increased as much as possible; the maintenance of the mold should be carried out in time, such as cleaning (plating, Teflon spraying, sandblasting), etc.
2. The structural design of rubber products should be easy to demold and have sufficient slope.
3. Choose a reasonable and appropriate viscosity formula. Properly adjust the vulcanization system, especially rubber products, increase the amount of accelerator; add carbon black to enhance or adjust the original formula.
4. If you are not familiar with vulcanization, you can solve it by increasing the vulcanization time and temperature. For products with more complicated structures, special attention should be paid to the demolding method to improve the operation level of the demolding workers.
5. The cost allows you to add an appropriate amount of internal release agent to the rubber material, reducing the frequency and amount of spraying release agent, which can effectively prevent the release agent from contaminating the surface of the cavity, so that it is difficult to mold.
6. Use a certain amount of release agent.