Material comparison
Acetal vs nylon: moisture, fit, wear and load.
Acetal is often a useful starting point when detailed geometry and dimensional fit dominate. Nylon is often worth evaluating for loaded wear and impact. Moisture, temperature and the exact grade can change which material suits the component.
Start with the condition that controls the part.
Neither material is an overall winner. These tendencies apply to material families; the proposed grade and complete operating duty determine the useful comparison.
| Requirement | Acetal | Nylon |
|---|---|---|
| Close bore, gear mesh or locating detail | Rigidity and lower moisture uptake help with detailed fits. Heat, creep, stock stress and inspection state still matter. | Moisture can alter a close fit. Exact grade and the condition in which the fit must work are central. |
| Humidity, washdown or immersion | Absorbs less moisture than nylon, but uptake is not zero. Chemistry, temperature and load still govern suitability. | Moisture changes dimensions and properties. A dry inspection result may differ from the condition in service. |
| Shock, jams, vibration or repeated impact | Useful when stiffness and fit also matter. Impact, notches, temperature and grade need consideration. | Toughness and damping can be useful. Moisture, fillers, cold conditions, section geometry and sustained load affect the result. |
| Loaded bushing, roller, gear or wear pad | Worth comparing for stiffness and clearance control. Pressure, motion, heat and mating surfaces still govern wear. | A loaded-wear candidate. Counterface, lubrication, debris, speed and duty determine whether it suits the interface. |
| Sustained load, press fit or clamping | Creep can change retention over time. Long-term behavior depends on stress, temperature and the retained geometry. | Also creeps, with moisture state adding another variable. Wall section, stress, time and heat matter. |
| Large stock section or cast shape | Grade, form and section must suit the part. The family name does not establish availability or stock stress. | Cast nylon offers a route to large shapes. Cast and extruded grades, condition and availability need distinction. |
A fit can change between inspection and service.
Nylon generally absorbs more moisture than acetal. That uptake can change both finished dimensions and mechanical behavior. A bore accepted in a dry state may encounter different conditions during assembly, washdown or immersion.
The relevant fit might be a running clearance, press-fit retention, gear mesh or alignment. Acetal's lower uptake helps narrow the comparison, but does not eliminate temperature and moisture effects.
A fit has a material state as well as a dimension
Machining
The stock begins in a particular grade and moisture condition. That starting condition is part of the dimensional history.
Inspection
The measured fit describes the stated temperature, support and dry or conditioned state at acceptance.
Assembly
A shaft, housing or mating part introduces a clearance, interference or locating relationship.
Service
Humidity, immersion, washdown and temperature can change the material state after the part has been assembled.
Wear, impact and sustained load are different demands.
A rotating bushing, loaded roller and stationary clamped feature experience different duties. A useful comparison includes the complete interface, including lubrication and contamination, as well as the plastic itself.
Nylon can be a useful loaded-wear candidate, while acetal may be favored when stiffness and clearance control dominate. Neither a low-friction description nor a material name establishes wear life or dry-running suitability.
Wear belongs to the complete moving interface
Rotating shaft and stationary bushing
The shaft rotates against the bore at the illustrated contact. Shaft finish, clearance, alignment and the plastic grade influence friction and wear.
Load, motion and heat
Rotation and contact generate frictional heat. A parked load, a start or stop, and an impact each place a different demand on the part.
Impact is a short event.
A jam or repeated strike can place concentrated stress at a corner or notch. Nylon's toughness can be useful, but moisture state, cold conditions, fillers and the actual section influence the response.
Creep develops over time.
A parked load, press fit or fastener can remain stressed long after a moving cycle ends. Both families creep. Long-term grade data, temperature, moisture and the retention geometry are needed to evaluate that relationship.
Compare the grade, stock process and environment.
“Acetal versus nylon” narrows the material families. It does not yet identify the stock from which the part will be made.
- Acetal and Delrin
- Acetal includes POM-C copolymer and POM-H homopolymer. Delrin is a branded acetal homopolymer family. A Delrin-versus-nylon requirement needs the exact grades, with current branded supply confirmed separately.
- Nylon and Nylatron
- PA6, PA66, cast and extruded nylon are not interchangeable descriptions. Modified grades can change wear, stiffness or other behavior. Nylatron is a controlled brand and grade designation; its supply is not implied by a generic nylon request.
- Stock and material removal
- Cast and extruded stock can differ in stress and property behavior. Section size, thin walls and asymmetric material removal may influence distortion. Cast stock is not automatically the better route for every part.
- Heat and chemical exposure
- A heat-deflection test value is not a maximum service temperature. Hot water, steam, cleaners and process chemicals require exact-grade review at the relevant concentration, time, load and temperature. POM-C and POM-H can differ in chemical-service behavior.
Quote your acetal or nylon machining requirement.
CDS machines customer-specified acetal and nylon parts and supplies stock from these families. The customer drawing establishes the material, geometry and required fit. CDS confirms machining feasibility against those supplied requirements.
- Drawing and grade: revision, specified material and brand, stock-process requirement and any permitted alternatives.
- Finished-part acceptance: dimensions, tolerances, datums, surface requirements and any specified temperature or moisture condition at inspection.
- Order and records: quantity, needed date and required material, inspection or traceability documents.