Plastic injection machine

Plastic injection machine is an indispensable part of manufacturing plastic products, with many vital components. These parts are prone to wear over time and improper maintenance, especially the screws of injection molding machines. In this article, we will delve into the various factors that cause screw wear and give corresponding solutions.

The impact of screw wear on the performance of plastic injection machine

Screw wear is a common problem in plastic injection molding machines, affecting their performance and productivity. As the screw wears, it loses its ability to melt and mix plastic resins effectively. This can lead to inconsistencies in melt temperature, viscosity, and composition, resulting in poor part quality, surface defects, uneven filling, and more. Worn screws require higher temperatures and pressures to achieve proper plasticization, which increases energy consumption and operating costs. Additionally, inefficient mixing and melting processes can require longer cycle times, impacting energy efficiency and throughput. Screw wear can also cause shot volume and injection pressure to vary from cycle to cycle, resulting in inconsistent part size, weight, and mechanical properties.

Identify common causes of plastic injection machine screw wear

First, wear can result from improper use, such as running the machine at high temperatures or pressures or using unsuitable plastic materials. Secondly, insufficient surface treatment of the screw can also cause wear, such as inadequate hardening or uneven coating. In addition, impurities or fillers in plastic particles can increase wear, significantly harder particles or fillers. If used for a long time without regular maintenance, it is also an essential factor in screw wear. Operating the machine at too high a speed or under high pressure will increase wear and lead to premature failure.

Optimize setting parameters to reduce screw wear

Optimizing processing parameters before operation can reduce plastic injection machine screw wear. First, controlling the injection speed can reduce the stress on the screw during the injection process because slower injection speeds allow for better flow control and reduce abrasive contact between the plastic melt and the screw surface, thereby reducing wear. Secondly, the temperature setting is crucial. Maintaining proper melt temperature ensures even flow and reduces the risk of overheating, which accelerates screw wear. Reasonable temperature control also helps prevent plastic materials from degrading, reducing wear and tear. Third, adjusting the injection pressure can also reduce screw wear. Excessive pressure may cause unnecessary friction and wear on the screw.

Prevent wear and tear using wear-resistant coatings and treatments

Wear-resistant coatings and treatments on the screws of plastic injection molding machines can also prevent wear. A standard method is to apply a hard coating such as nitriding, chromium plating, or tungsten carbide coating. These coatings significantly increase the surface hardness of the screw, making it more resistant to wear caused by contact with plastic materials during injection. Another method involves surface treatment, such as shot peening or laser surface modification. Shot peening bombards the screw surface with fine metal particles to generate compressive stress and enhance its fatigue and wear resistance. Laser surface modification selectively melts and re-solidifies the surface layer, improving its hardness and wear resistance.

Helps detect screw wear through monitoring and analysis

The wear of plastic injection machine screws can be easily detected through monitoring and analysis technology. Implementing a comprehensive monitoring system enables operators to track critical parameters during the injection process, identifying any deviations or anomalies that may indicate screw wear by monitoring operating conditions such as temperature, pressure, and torque in real-time. Any unusual fluctuations in these parameters, such as a sudden increase in torque or a change in melt temperature, may indicate underlying screw wear. Integrating sensors and data acquisition systems directly into plastic injection molding machines can provide continuous feedback on screw performance. By analyzing trends in data collected over time, operators can identify patterns indicative of wear so they can intervene before significant damage occurs.


Preventing screw wear can extend the life and performance of your plastic injection machine. By clarifying the causes of wear in the article and taking preventive measures such as proper maintenance, optimizing setup parameters, and using wear-resistant coatings, manufacturers can reduce downtime maintenance costs, and ensure consistent production quality.

By Admin

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