Requirements for injection molding of PP fast food box: […]
Requirements for injection molding of PP fast food box:
Combines the characteristics of PP material with the essence of thin-wall injection molding. We can get the requirements of PP fast food box for injection molding machine, in simple terms, it is the following three points.
1. High-response fast injection: Thin-walled products are very light, so the range is very short. The machine needs to reach a high injection speed within 0.3~0.5 seconds to complete the injection before the flow channel forms an excessively thick solidified layer. If the response is slow, the absolute shooting speed (generally the injection speed is calculated based on the empty shooting) cannot reach the best due to the excessive resistance of the mold cavity. To make the solidified layer too thick to fill the cavity, the injection pressure can only be increased.
2. Low pressure injection. High-pressure injection will only increase the required clamping force, which will cause internal stress to the product, and the finished product will be deformed after demolding; at the same time, it increases the density of the product and makes the product heavier; and it will increase the impact on the machine and the mold. Wear.
3. Low temperature injection. PP material for fast food, when the temperature exceeds 300 degrees, the product will become brittle. It will be damaged during transportation or use.
The essence of PP fast food box filling
PP fast food box products are low-value products. Generally speaking, fast production and short cycle time are cost-effective. Based on the normal calculation of a mold in about 5-6 seconds, the temperature of the mold is basically reduced with 5-10 degrees of cold water. Then during the filling process, the mold wall is very cold. When the mold cavity is melted and filled, the mold wall will form a solidified layer, thereby reducing the thickness of the flowable channel.
This situation becomes more serious when the wall thickness is thinner. Generally, the thickness of the PP fast food box does not exceed 0.5mm; if the 0.5mm wall thickness has a solidified layer of about 0.2mm, the flow channel is left with a thickness of 0.1mm, which will be difficult to fill. When the filling is not completed and the flow channel disappears due to the thick solidified layer, the finished product will not be filled. This is also the fundamental reason why the PP fast food box needs a fast injection molding machine.