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Matters needing attention in the production of injection moulds
- 2020-04-03-

The processing of injection molding molds and injection molding requires many complex steps. First, we need to enter the filling stage. For a mold, we need to start filling when it is closed until its cavity is filled to a certain extent. During the spraying process, the spraying speed should be controlled within a reasonable range. Generally speaking, the shorter the filling time, the higher the molding efficiency. Then there is the pressure holding stage. What we have to do in this stage is to continuously apply pressure, which can compress the melt and increase the density of the plastic to resist the shrinkage of the plastic. This stage is also maintained until the end of plastic molding, until the gate is solidified and sealed to achieve the best results.

Matters needing attention in the production of injection molding molds:
1. The two shapes of the front mold are different to form a product. The two shapes of the rear mold are identical.
2. After the front mold center rotates 180 °, it must be consistent with the rear mold. This must be noted in the design.
3. During the design process, please carefully check the parameter data of the two-color injection molding machine, such as the maximum mold thickness, the minimum mold thickness, and the spacing of the ejector holes.
4. The nozzle design of the three-piece mold is best to automatically demold. Pay special attention to whether the mold release action of the soft rubber nozzle is reliable.
5. In the cavity design of the second injection molding, in order to avoid the cavity insertion (or friction) damage to the rubber position of the first molded product, a part of the cavity can be designed to avoid the cavity. However, the strength of each sealing position must be carefully considered, that is, whether there is a possibility of plastic deformation under a large injection pressure during the injection molding process, resulting in the possibility of a batch front during the second injection molding.
6. In the injection molding process, the product size of the first injection molding can be slightly larger, so that in the second injection molding, another cavity can be squeezed more tightly to achieve the sealing effect.
7. Pay attention to whether the plastic flow during the second injection will impact the first molded product and deform its glue position. If this is possible, we must strive to improve it.
8. During injection molding, the hard part of the product is injected first, and then the soft part of the product is injected because the soft rubber is easily deformed.
9. In order to make these two plastics "sticky" tighter, we should consider the "stickiness" between the materials and the surface roughness of the mold. Two-color injection molding has a special TPU; the smoother the mold surface, the tighter they “stick”.