How to Resolve Flow Patterns on the Surface of Injection Molded TPR Toy Materials
Source：德创化工Time：2020-03-16Hits：2204
Do you often encounter streaks in the process of injection molding TPR toy products? How to solve it?
We start from three aspects: 1. Materials; 2. Process; 3. Mould
The first aspect: TPR material
If the fluidity of TPR material is not enough, it is easy for the product to have streaks, or if the internal compatibility of TPR material itself is not enough, streaks will also occur. The specific material can be solved by the manufacturer.
The second aspect: injection molding process
Insufficient plasticization of materials, here insufficient plasticization refers to insufficient plasticization of injection molding, mainly in two aspects: insufficient injection molding temperature and appropriate back pressure. The injection temperature should be appropriate. Too high can easily lead to bubbles or scorching. The injection back pressure of TPR material is generally 0.3-2MPA, which strengthens the plasticizing effect of screw and ensures the injection effect.
The third aspect: mold
Mold design is very important, including runner, glue inlet and cooling water pipe passage.
1. The runner design should be reasonable and should not be too long. Too long will cause the material to cool in the runner, resulting in uneven cooling when entering the mold cavity, leading to the occurrence of flow lines.
2. If the glue inlet is too small, the product will be sputtered into the mold cavity wall, and different cooling will lead to flow pattern. If the glue inlet is for the same product at two points, the two glue inlets need to be kept at an appropriate size. If the glue inlet is at the same position, the size of the glue inlet needs to be kept the same. The aim is to ensure consistent glue feeding speed, so that it is not easy for products to flow.
3. Cooling water pipe passage. Most of the time, it often happens that at the beginning, it is not possible to do so. The mold will be heated. This has something to do with the design of the passage. Constant temperature water is introduced to ensure that the temperature of the mold is set within a certain range, thus ensuring the effect of injection molding products.
