plastic gear Technical Overview

Which Lubricant is Best for Plastic Gears?

Selecting the right lubricant for plastic gears is critical — the wrong choice can cause material degradation, increased wear, or even catastrophic failure. Here is UNITECH-GEAR's comprehensive guide:

Recommended Lubricant Types

Synthetic Hydrocarbon Greases: The most widely recommended option for plastic gears. Excellent compatibility with POM, PA, PBT, and most engineering plastics. Good load-carrying capacity and wide operating temperature range (-40°C to 150°C). Will not attack or soften plastics. Brands like Klüber Isoflex and Molykote EM series are industry standards.

Silicone-Based Greases: Excellent for low-load, low-speed applications. Outstanding plastic compatibility and the widest temperature range (-50°C to 200°C). However, lower load-carrying capacity limits use in high-torque applications. Ideal for instrument gears and precision mechanisms.

PTFE-Fortified Lubricants: Polytetrafluoroethylene (PTFE) additives significantly reduce friction coefficients (as low as 0.04). Excellent for high-cycle applications where long maintenance intervals are desired. Particularly effective for POM-on-POM and POM-on-PA gear pairs.

PFPE (Perfluoropolyether): Premium lubricants for extreme environments. Chemically inert, radiation resistant, and operational from -70°C to 250°C. Used in aerospace, semiconductor, and medical applications where cost is secondary to absolute reliability.

Lubricants to AVOID

Never use mineral oil-based greases on plastic gears. They can cause Environmental Stress Cracking (ESC) in many engineering plastics, particularly amorphous polymers. Avoid lubricants containing certain EP (Extreme Pressure) additives, aromatic hydrocarbons, or ester-based oils unless specifically tested for compatibility with your plastic material.

Application Best Practices

Apply lubricant sparingly — a thin, even film on tooth flanks is sufficient. Excess lubricant attracts contaminants, increases churning losses, and can cause overheating at high speeds. For enclosed gearboxes, ensure lubricant viscosity is appropriate for the full operating temperature range. Consider grease retention features (labyrinth seals, felt wicks) in your housing design.

Pro tip: When in doubt, request a material compatibility test from your lubricant supplier using your specific plastic grade. Most major lubricant manufacturers offer this service at no charge.