The solution to the phenomenon of dragging of the electroplated mold during injection molding

In order to prevent the core and cavity of the mold from rusting, some mold cavity parts need to be electroplated to make the surface look very bright. However, when the transparent plastic is injected, the product is often dragged (the mold is removed by the core). Scratch the obvious pattern).

In fact, a bright mold is not necessarily smooth, and the friction between it and the injection molded part is actually very large. Usually, it is not allowed to spray release agent when producing transparent plastic parts, so the hot injection parts are like sticking to the mold, and the longer the mold production time, the more serious this feeling. This is because the oil stains immersed in the metal surface of the mold during the manufacturing of the mold will become less and less, and the glue stains left by the injection molded parts will also increase, so the friction becomes greater and greater, and the problem of dragging is like this produced. If the mold release angle is insufficient, it is more likely to cause dragging of the injection molded parts.

In order to reduce the friction between the product and the mold, in fact, we only need to use the diamond paste for polishing the mold to polish the position of the drag in the mold. This will not only remove the glue stains on the mold, but also make a small amount of oil stains immerse into the metal. The surface will also become smooth, and the problem of smearing can usually be solved.

Many middle and junior level technicians generally don’t dare to do this, because they are worried that they will spoil the mold. In fact, we only need to pay attention to rubbing the mold with cotton dipped in diamond paste instead of a cloth to avoid fouling the mold.

On-site treatment methods when light spots appear on matt injection molded parts

After sandblasting or etching the mold, the surface of the injection molded part should have a matte (matte) effect. But after a period of injection molding production, the surface of the injection molded parts will appear bright spots in some places, which are inconsistent with the surrounding matte.

Observing the mold, you can also see that there are bright traces in the corresponding position. At this time, most people will immediately determine that the sand pattern or etch pattern of the mold has fallen off and become light, and then the mold is taken to re-blast or etch the pattern.

In fact, in most cases, it is not the problem of sand grains or etched grains falling off, but because the mold has been used for a long time, more gas stains, oil stains and glue stains have accumulated somewhere, causing the surface of the injection molded parts to become bright. Therefore, only need to clean thoroughly, the light spots of injection molded parts will be eliminated, but glue stain cleaner must be used instead of ordinary injection molded parts cleaner.
Therefore, once it is found that there are bright spots on the matte injection molded parts, which cannot be solved by adjusting the machine, the mold should be cleaned with a special glue cleaner. When it cannot be solved, it can be determined that the surface of the mold surface has been damaged, and it is not too late to re-blast or etch the pattern.

If there is a large area luminescence problem, it is likely to be a problem with the tuning. Insufficient injection pressure and insufficient injection or holding time are usually important reasons for the luminescence of the surface of injection molded parts, and too high melt temperature is also an influencing factor.