Generally speaking, the barrel, screw and check ring of the old injection molding machine mostly wear to different degrees, and the cooperation gap between them will be relatively large, especially the injection molding machine that often produces POM and PVC Big. Due to the increased gap, during injection, part of the melt will flow back [...]
In the injection molding production process, when adjusting the machine becomes difficult, trying to make some changes in the mold is a wise choice to solve the injection molding problem. Changing the position of the gate, changing the size of the runner, and adjusting the filling speed of each cavity are some of the commonly [...]
In a multi-cavity mold, the filling speed of various cavities is often uneven (unbalanced). Some cavities are filled quickly, and some are filled slowly. At this time, injection parts with fast filling are prone to problems such as overflow, white top and trapped gas, while slow filling is prone to shrinkage or insufficient filling. The [...]
In order to prevent the core and cavity of the mold from rusting, the cavity parts of some molds need to be electroplated and make their surfaces look very bright, but the product is often smeared when the transparent plastic is injected (scraped by the core when demolding) Out of obvious patterns). In fact, the [...]
The lifting of larger molds often needs to be hoisted by cranes. Because of the need for mold repair in the production process, only half of the molds need to be disassembled. When the repair is completed and the half of the mold is hoisted and installed, the single side mold is often Too tight [...]
At high temperatures, the friction between the K material (styrene-butadiene copolymer, SB in English, commonly known as "K material") and the surface of the metal mold is very large, so the release resistance of the K material injection molded parts will be quite large, resulting in production It often happens that the ejector pin and [...]
In a multi-cavity mold injection molding, the filling speed of each cavity of many molds will be more or less imbalanced, whether it is fast or slow, if this phenomenon is not obvious, generally it will not produce product quality. Too much impact. However, if there is a serious filling imbalance, for example, one cavity [...]
For plastic melts that obey Newtonian flow laws, since the viscosity is independent of the shear rate, a large gate cross-sectional area can reduce the flow resistance and increase the melt flow rate, which is more favorable for mold filling and molding quality. For most plastic melts that do not obey the Newtonian flow law, [...]
1, The reason why the trapped gas of PP and PVC injection molded parts is difficult to solve by adjusting the machine When the injection molded parts have trapped gas problems, they usually appear to be filled with dissatisfaction, or scorched, whitish, and have coarse gas lines. Many trapped gas problems can generally be solved [...]
Many people know that trapped gas is caused by poor exhaust of the mold during the injection process, which is only one of the reasons. In fact, there is another important reason that can cause severe gas traps in injection molded parts, which is caused by the phenomenon of melt `` back pack '' during [...]
