To solve the problem of streaks and weld marks on PVC parts, first of all, the speed of melt injection into the cavity must be reduced to prevent the folding wave or spiral injection, or the occurrence of unstable filling phenomena such as melt shunt. However, sometimes due to the mold cavity being too wide, [...]
Sometimes, the cavity space at the gate position is too large, which makes it difficult to eliminate weld marks and streaks. This requires an extremely low first-level injection speed for injection to reduce or eliminate the weld marks and streaks. But if the injection speed is too slow, the heat dissipation time of the melt [...]
As mentioned in the previous column, to eliminate the streaks and weld marks of thick PVC parts, first of all, it must be ensured that when the melt is injected into the cavity from the gate, folding wave (snake type) or spiral injection cannot occur. The cavity must be filled smoothly and no shunts are [...]
I have introduced a lot of thick PVC streaks adjusting techniques and improvement measures. However, if you can start with the mould and completely eliminate the root cause of this problem in the mould design-the cavity space at the gate position is too large, the streaks problem will not occur at all, and the same [...]
In injection molding production, it is often encountered with thick PVC injection molded parts with a wall thickness of more than 50mm. Because the internal space of the cavity is too large, when the melt is injected from the gate into the wide cavity, the squeezed melt will be injected into the cavity from the [...]
The oil injection mold is manufactured using injection parts as a model, so mass-produced injection parts must be the same as the injection parts when manufacturing the injection mold to avoid the problem of flying oil (paint splashing) during injection. In order to obtain injection parts that are consistent with normal production, for large injection [...]
For low hardness PVC and rubber injection parts with a hardness value less than 80 degrees (Shore hardness, GB / T2411—2008), the problem of oil loss has always been a quality problem that is difficult to control and guarantee during production in the oil injection department. The lower the hardness, the more It is difficult [...]
① Try not to use release agent. When it must be used, only dry release agent or neutral release agent can be used to lightly spray the moving mold (commonly known as "back mold"), but the injection molded parts that need to be plated must not be used. When spraying, pay attention to that the [...]
If the nozzle used is long, the melt is easy to cool during injection molding, and a lower temperature condensate will be generated at the front end of the nozzle. When the cavity is injected into the cavity, the cavity will be underfilled, and the other cavity will overflow due to overfilling. Especially when injecting [...]
Small injection molding machines are used for injection production with large molds. Even if the molds can be installed, the ejection force of the injection molding machine is insufficient, and the injection parts are difficult to eject. Therefore, the operator often has to adjust the ejection speed of the ejector rod. To form an impact [...]
