In injection molding machine maintenance, is bushing material selection really just about price?

During injection molding machine maintenance and overhaul, we often see different bushing materials used in crankshaft and tie bar guide applications, such as:
aluminum bushings, steel bushings, zinc-based alloy bushings, and self-lubricating bronze bushings.
From a short-term perspective, all of these materials can "work".
However, when we look at long-term stability, wear performance, and maintenance cost, the differences become very clear.
Based on years of field experience, we have observed that:
Most Japanese and Taiwanese mid- to high-end injection molding machines use self-lubricating graphite bronze bushings in critical load-bearing positions.
The reasons are mainly:
• More stable wear resistance, with minimal clearance change over long-term operation
• Excellent heat dissipation of copper alloys, reducing thermal deformation and abnormal wear
• Self-lubricating properties that provide better safety under insufficient lubrication or maintenance lapses
Although the unit cost of a self-lubricating bronze bushing is higher than aluminum or zinc-based alloy bushings,
when considering downtime frequency, labor cost, machine stability, and service life,
it often becomes the most cost-effective solution over the full lifecycle.
With proper material selection and correct installation,
stable operation of critical components for over 10 years is not uncommon.
Another often overlooked but critical factor is installation method:
Cryogenic installation using liquid nitrogen is strongly recommended.
Direct hammering or forceful installation should be avoided, as it can damage internal stress distribution and roundness, significantly increasing the risk of premature mechanical failure.
👉 Long-term machine reliability depends on both correct material selection and proper installation.
👉 For injection molding machine maintenance, RAMSHIN self-lubricating bronze bushings provide a more reliable and professional solution.