Property of friction between macromolecules when molten plastic flows is called plastic viscosity. Coefficient of this viscosity is called viscosity, so viscosity is a reflection of fluidity of molten plastic. The greater viscosity, the stronger viscosity of melt, the worse fluidity and the more difficult processing. In industrial applications, comparing fluidity of a plastic is not based on its viscosity value, but on its melt flow index (called MFI): so-called MFI means that at a certain melting temperature, melt is subjected to a rated pressure, weight of melt passing through standard die per unit time (usually 10 minutes). It is expressed in g/10min, such as injection molding grade PP material, grade is different, MFI value can vary from 2.5 to 30. Viscosity of plastic is not static. Change of characteristics of plastic itself, influence of external temperature, pressure and other conditions can all contribute to change of viscosity.
Tag: injection cycle
In this increasingly competitive business society, improving production efficiency is an issue worthy of attention. This article describes a variety of ways to improve injection cycle by using existing or newly designed injection molding machines or molds. Injection cycle Injection cycle of a hydraulically driven injection molding machine refers to start of mold clamping to … Continue reading How to shorten injection cycle?
Product diagram of motor mounting box is shown in Figure 1. Maximum size of product is 209.48 mm * 168.40 mm * 138. 15mm, average thickness of plastic part is 2.40mm, material of plastic part is fireproof ABS, shrinkage rate is 1.005, and weight of plastic part is 235.70 grams. Technical requirements for plastic parts are that there must be no defects such as peaks, underfilling of injection molding, flow lines, pores, warpage deformation, silver streaks, cold materials, jet lines, etc.
Injection moulding is an engineering technique that involves transforming plastic into a product that is useful and maintains its original properties. Important process conditions for injection moulding are temperature, pressure and corresponding individual time of action that affect plasticizing flow and cooling.
Gud Mould 