Wear-Resistant and Low-Friction POM Selection Guide

Wear Resistance and Low Friction Are Not the Same Requirement

Wear resistance describes how well a material resists surface loss, scoring, deformation, or other damage during repeated contact. Low friction describes the resistance generated when one surface begins or continues to move against another. These properties are related, but they should not be treated as interchangeable.

A low-friction material may reduce operating force without necessarily providing the longest wear life under high load. Conversely, a highly wear-resistant material may maintain its dimensions over repeated cycles but still produce more friction, noise, or heat than the application allows.

The distinction becomes important in practical component selection. A bushing may need long service life with minimal dimensional change. A slider may require smooth initial movement and limited stick-slip. A gear may need stable tooth geometry, acceptable noise, and controlled wear on both surfaces. A valve moving part may need predictable movement after long periods of inactivity.

• Is the molded POM part wearing too quickly?
• Is the mating component being damaged?
• Is the movement force too high or inconsistent?
• Is the mechanism producing noise, vibration, or stick-slip?
• Is external lubrication unavailable or undesirable?
• Is dimensional change affecting positioning or sealing?

Review Load, Speed, and Movement Pattern Together

Load should be reviewed at the contact surface, not only as the total force applied to the component. A small contact area can create high local pressure even when the overall load appears moderate. Edge contact, misalignment, sharp geometry, and uneven assembly can further increase local stress.

Speed also influences wear and friction behavior. Slow movement can create stick-slip or high breakaway force, while faster movement may generate frictional heat. The effect of speed depends on the load, mating surface, lubrication condition, and movement duration.

Continuous rotation, repeated oscillation, short sliding strokes, and occasional actuation do not produce the same wear conditions. A roller running continuously may require a different material direction from a valve component that remains stationary for long periods and then moves suddenly.

Use MoS₂-modified EMS102/EMS162 to compare wear and mechanical properties: EMS102 for flow-sensitive complex parts, EMS162 for tensile-led drives. Include ENM1040 and EDM-111 as alternative wear formulations and compare wear, clearance and temperature with the same contact pair.

Mating Material and Surface Finish Can Change the Result

A POM component does not wear independently. Its behavior is strongly affected by the material and surface condition of the part it contacts. Steel, aluminum, brass, coated metal, rubber, POM, PA, and other engineering plastics may each produce different friction and wear results.

Surface finish is equally important. A rough metal surface can act as an abrasive and remove material from the polymer. A damaged, corroded, poorly machined, or contaminated mating surface can cause rapid wear even when a suitable modified POM has been selected.

Hard fillers or reinforcing fibers should also be reviewed for their possible effect on the counterpart. A reinforced POM may improve stiffness and dimensional control but could increase wear on a softer mating surface.

When deformation and sliding friction both dominate, start with PTFE/glass-modified EGH20-TF; use EPAF100A as the aramid baseline. Inspect mating-surface scratches and molded finish alongside reinforcement gains.

Choose the lubrication system by motion and load

Start PTFE and silicone-oil comparisons with sliding resistance and smoothness; MoS₂ with wear/mechanical balance; aramid or glass blends with support stiffness. Group candidates by dominant failure and test on the same mating surface.

For low-speed starts or dry sliding, use PTFE-modified EPTL402 as the baseline for starting resistance and stick-slip. If more stiffness is needed, add EGH20-TF and compare deflection and mating-surface wear.

MoS₂-modified EMS102/EMS162 establish wear/tensile tradeoffs; silicone-oil-modified ESO102 provides a comparison for operating force and feel. Record steel shafts, plastic shafts and external lubrication separately, with wear and torque for each pair.

ENM1040 and EDM-111 are other listed wear formulations. When PTFE, MoS₂ or silicone-oil systems miss the target, include them in the same-condition comparison of wear, molded surface and dimensional retention.

• Required wear life
• Static and dynamic friction
• Mechanical strength and stiffness
• Dimensional tolerance
• Counterpart material and hardness
• Dry or lubricated service
• Noise and movement quality
• Surface and secondary-process requirements
• Production stability and moldability

Lubrication, Noise, and Stick-Slip Should Be Evaluated Separately

The first question regarding lubrication is whether the component operates dry, with grease or oil, or with occasional contact from process fluids. A material that performs well in dry sliding may not provide the same advantage in an externally lubricated system.

When external lubrication is unavailable, compare the internal lubrication systems of EPTL402 and ESO102. Record dry starts, steady running and operation after prolonged rest to assess the dominant friction problem.

Noise is also not controlled by friction alone. Gear noise, squeaking, chatter, and vibration may be influenced by dimensional accuracy, stiffness, tooth profile, assembly clearance, surface finish, resonance, lubrication, and molding variation.

Stick-slip occurs when the force required to begin movement is significantly different from the force required to continue movement. It is often important in sliders, guides, adjustment mechanisms, valve controls, seats, and slow-moving components.

Counterpart Wear Can Be More Important Than POM Wear

Material evaluation often focuses only on the weight loss or dimensional change of the POM component. This can produce an incomplete conclusion. The mating surface may experience polishing, scratching, coating removal, abrasion, or dimensional damage even when the POM part appears acceptable.

This is especially important when POM runs against soft metals, plated components, painted surfaces, sealing elements, or another molded polymer. Reinforcing fibers and some functional fillers may alter the wear mechanism of the contact pair.

A successful tribological material should therefore be evaluated as part of a two-surface system. Tests should inspect both the POM component and the counterpart. Engineers may need to review dimensional change, wear debris, surface damage, operating force, temperature rise, noise, and the stability of the contact area.

Measure both driver and driven gear wear. For steel–plastic pairs, check polymer profile, metal surface and heat; for plastic–plastic pairs, check debris, backlash and heat buildup on both sides and record the complete material pair.

Why Laboratory Wear and Friction Data Are Not Enough

Laboratory values are useful for preliminary comparison, but tribological results are highly dependent on the test method. A coefficient of friction or wear rate measured under one set of conditions may not predict performance in another system.

Even data from two suppliers may not be directly comparable when the test methods, specimen preparation, conditioning, or counterpart surfaces are different. A lower reported friction value should not automatically be interpreted as better component performance.

Molded parts introduce additional variables that standard laboratory specimens may not represent. These include gate position, weld lines, shrinkage, orientation of fibers or fillers, residual stress, surface replication, part warpage, and dimensional tolerance.

Molded-part trials should therefore reproduce the real assembly as closely as possible. Testing should use the actual counterpart material, representative load and speed, expected lubrication condition, and a meaningful number of operating cycles.

• Test specimen geometry
• Counterpart material and hardness
• Surface roughness
• Contact pressure
• Sliding speed
• Movement direction
• Test duration
• Temperature and humidity
• Dry or lubricated conditions
• Initial running-in period

What to Send Before Grade Recommendation

Submit motion, mating material and current wear or stick-slip for a candidate-grade comparison, TDS and trial-sample support. Use available load, speed and lubrication information to define measurements for the trial.

Use this information to choose a material direction. Then review the applicable TDS, mold representative parts, and test them under actual or closely simulated operating conditions.

• Part name, drawing, photo, and main function
• Current material or current grade
• Current failure mode or performance problem
• Type of movement: sliding, rotation, oscillation, rolling, or intermittent actuation
• Load, contact pressure, speed, sliding distance, and duty cycle
• Expected service life or number of cycles
• Mating material, hardness, coating, and surface finish
• Dry operation or lubricant type
• Operating temperature and environmental conditions
• Noise, stick-slip, or operating-force requirements
• Existing TDS, test reports, wear samples, or failed components