5 Injection Molding Maintenance Mistakes To Avoid
August 01, 2025
Effective injection molding equipment maintenance is the backbone of any high-volume plastics operation. Yet many shops fall prey to common pitfalls that shorten press life, increase downtime, and drive up repair costs. Below are the top five injection molding maintenance mistakes—and the proven remedies to keep your line running smoothly.
1. Skipping Daily Lubrication
Mistake: Operators skip greasing tie bars, toggle joints, ejector guides, and other lubrication points under the assumption that electric or servo-driven systems “don’t need it.”
Impact: Metal-to-metal wear accelerates, leading to increased friction, erratic clamp force, and premature bushing failure.
Solution: Implement a concise daily maintenance checklist. Use color-coded grease fittings, and train operators to spend five minutes each shift on lubrication. Log each task digitally in your CMMS for audit trails.
2. Ignoring Hydraulic Fluid Health
Mistake: Waiting six months or more to sample and analyze hydraulic oil, often until a failure occurs.
Impact: Water contamination, particulate build-up, and acidification degrade seals, pumps, and valves—ultimately causing leaks and pressure loss.
Solution: Perform hydraulic fluid analysis monthly. Monitor viscosity, water content, and particulate counts. Schedule oil changes and filter replacements based on ISO cleanliness targets rather than calendar dates.
3. Overlooking Filter and Strainer Cleaning
Mistake: Neglecting suction-side strainers, pressure filters, and cooling-water strainers until they’re fully blocked.
Impact: Restricted flow raises pump temperature, reduces clamp force, and triggers unplanned downtime.
Solution: Assign weekly filter inspections to maintenance techs. Keep a stock of OEM filter elements. Use pressure-differential gauges to signal when replacement is due.
4. Neglecting Barrel and Screw Inspections
Mistake: Failing to regularly check screw flights and barrel liners for wear or resin build-up.
Impact: Diminished melting efficiency, inconsistent melt temperature, short shots, and flash result in off-spec parts.
Solution: Schedule quarterly screw-and-barrel inspections. Measure flight depth with a micrometer. Clean resin deposits with a chemical barrel cleaner or a dry-granule purge. Replace worn screws proactively.
5. Skipping Control-System Firmware Updates
Mistake: Running outdated PLC software and HMI firmware indefinitely, ignoring vendor patches and security fixes.
Impact: You miss process-control enhancements, cybersecurity protections, and bug fixes—putting uptime and part quality at risk.
Solution: Enable automatic firmware alerts. Pilot updates on a demo cell before plant-wide rollout. Document version changes and operator sign-off in your digital log.
Best Practices for Preventative Maintenance
Correcting the above errors offers immediate benefits, but a world-class preventative maintenance schedule for injection molding presses takes you further:
1. Digital Maintenance Logs: Transition from paper to CMMS. Attach photos of worn parts and oil-analysis reports to each task.
2. Predictive Maintenance Technologies: Deploy vibration sensors on electric motors and infrared thermography on hydraulic manifolds to catch anomalies early.
3. Operator Training & Accountability: Certify operators in basic press maintenance. Use “skill badges” and gamify lubrication and inspection tasks to ensure compliance.
By avoiding these five costly mistakes and embracing predictive, digital maintenance, you’ll minimize unplanned stoppages, extend equipment life, and unlock sustained cost savings.