Introduction to the Working Principle of Ball Screws

This article introduces the working principle of ball screws, highlighting their high mechanical efficiency and load capacity, which have led to widespread adoption in all-electric servo-driven injection molding machines. It compares ball screw design philosophies for machine tools and injection molding machines, noting that injection units experience loads hundreds to thousands of times greater. Key design priorities for high-load ball screws—such as uniform ball contact pressure, optimized lubrication, and enhanced durability—are discussed, with reference to Ningbo Superior's specialized solutions.

Surface Treatment and Service Life of Injection Molding Machine Screws

The screw and barrel are the most critical components of injection molding machines, operating under high temperature and pressure. Wear enlarges the clearance between the screw flight and barrel, reducing melting and pumping capacity, causing product quality degradation, lower productivity, and higher energy consumption. The screw is more susceptible to damage than the barrel.

How to Clean the Screw and Barrel of an Injection Molding Machine

Parameters of the Venting Section of Extruder Screws

This section examines the key parameters of the venting section in vented extruder screws. Venting effectiveness depends primarily on venting section length L, melt residence time, shear rate, and the fill factor F (the ratio of melt cross-sectional area to channel area). To ensure good performance, the venting channel should be partially filled; experiments suggest L ≥ 3D, F ≤ 0.5, and a shear intensity K > 100 for optimal degassing. For screws with L/D ratios of 24–30, the venting section length is typically 4D, and its channel depth is 2.5–6 times that of the first metering section. Design verification must include fill factor, shear intensity, and screw strength.