Thin-wall injection molding requirements for injection molding machines and molds(2)

- Apr 13, 2018-

As for the injection volume; large diameter barrels are often too large. The recommended injection volume is 40% to 70% of the barrel capacity. The shortening of the overall molding cycle of thin-walled products may reduce the minimum injection volume to 20% to 30% of the cylinder capacity. For materials, a small injection volume means that the material stays in the machine longer, which can lead to a decrease in the performance of the product.

Die speed is one of the key factors for successful thin-wall injection molding. Rapid filling and high pressure can inject molten thermoplastic material into the mold cavity at a high speed to prevent gate freezing. If a standard part is filled within 2 seconds, the thickness is reduced by 25% and it is possible to reduce the filling time by 50%.

One of the advantages of thin-wall injection molding is that when the thickness is reduced, less material needs to be cooled. As the thickness is reduced, the molding cycle can be shortened by half. Reasonable setting of the melt-conveying device will make the hot runners and runners not impede the shortening of the molding cycle, and the use of hot runners and sprue bushings helps to minimize the molding cycle.

In addition, mold materials should also be considered. P20 steel is widely used for molding traditional products, but because of the higher pressure of thin-wall injection molding, the mold must be made very strong. H13 and other hard steels add additional safety factors to thin-walled molds. However, the cost of a strong mold may be higher than that of standard molds by 30% to 40%. However, the increased costs are usually offset by increased production performance.