POM (Delrin) Parts Manufacturing

Precision POM / Delrin component manufacturing via 5-Axis CNC Milling, Precision Swiss Turning, and Rapid Prototyping. Delivering high rigidity, ultra-low friction, zero moisture absorption, and tight tolerances down to ±0.01 mm for sliding mechanical components.

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POM (Delrin / Acetal) Technical Specifications

Review key physical, friction, and mechanical properties of engineering-grade Homopolymer (Delrin 150) and Copolymer POM resin for your custom mechanical components.

Technical Property	Standard Value	Test Condition / Unit
Density	1.41 – 1.42 g/cm³	ISO 1183 / ASTM D792
Tensile Strength (Yield)	65 – 72 MPa	ISO 527 (50 mm/min)
Flexural Modulus	2.8 – 3.1 GPa	ISO 178
Coefficient of Friction (Dynamic)	0.20 – 0.25 (Self-Lubricating)	Dry steel contact
Moisture Absorption (24h)	0.20% (Ultra-Low)	ISO 62 (23°C immersion)
Heat Deflection Temp (HDT)	110 – 125 °C (230 – 257 °F)	ISO 75 (0.45 MPa)
Rockwell Hardness	M80 – M88 / R120	ISO 2039-2
Machinability Rating	Outstanding (100% Benchmark for Plastics)	Free-Cutting Plastic

Surface Finishing Options for Custom POM Parts

Enhance surface smoothness, remove microscopic machining burrs, and optimize low-friction wear surfaces.

As-Machined (Standard)

Clean raw surface straight from CNC turning or milling. Thanks to POM's exceptional machinability, it inherently yields extremely smooth surface finishes (Ra 0.8–1.6 µm) without secondary grinding.

Bead Blasting & Satin Texture

Uses fine glass beads to strip surface micro-lines, creating a clean, uniform, non-reflective matte satin texture for exterior medical housings and industrial knobs.

Cryogenic Deburring & Polishing

Freezes parts to freeze micro-burrs in tight internal threads and complex gear teeth, followed by high-speed media blasting for 100% burr-free precision.

Ultrasonic Cleaning (Degreasing)

Multi-stage ultrasonic bath cleaning that removes all coolant oils, cutting chips, and micro-particles, meeting medical, food-contact (FDA), and semiconductor cleanliness standards.

Laser Engraving & Marking

Applies sharp, permanent part numbers, serial codes, alignment marks, and corporate logos directly onto white or black POM surfaces without affecting wear properties.

Thermal Stress Relief Annealing

Controlled heat treatment cycle performed before or during heavy machining to eliminate internal residual stresses in thick-walled POM stock, guaranteeing zero long-term part warping.

Advantages and Considerations of POM (Delrin) Machining

POM is revered as “Plastic Steel” in engineering design. Review its core advantages and material limitations below.

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Advantages of POM (Delrin)

Superior Machinability & Tight Tolerances: Free-cutting plastic that produces short, crisp chips without burrs, routinely achieving tight metal-like tolerances down to ±0.01 mm.
Self-Lubricating & Low Coefficient of Friction: Exceptional natural wear resistance and smooth sliding performance, eliminating the need for external oils in precision gears and bushings.
Zero Moisture Absorption & Dimensional Stability: Absorbs virtually no water (<0.2%), ensuring parts maintain perfect fitment and dimensions even in submerged or humid marine environments.
High Mechanical Rigidity & Fatigue Endurance: Outstanding spring-back elasticity, high tensile strength, and impact resistance, capable of replacing brass or aluminum in light-load drive mechanisms.

Considerations & Limitations

Poor Surface Adhesion & Paintability: Highly chemical-resistant inert surface makes standard spray painting, adhesive bonding, and printing difficult without specialized surface treatment.
Centerline Porosity (Homopolymer Delrin): Thick-walled Delrin rod stock can exhibit micro-porosity at its center core during heavy drilling. *(Solution: Use Copolymer POM for thick block machining)*.
Vulnerability to Strong Acids: Degrades when exposed to strong acids (pH < 4) and prolonged exposure to high-concentration chlorine or UV sunlight.

POM (Delrin) Machining Manufacturing FAQs

1. What is the difference between POM Homopolymer (Delrin) and POM Copolymer?

Delrin (Homopolymer): Offers slightly higher mechanical tensile strength, stiffness, and hardness, making it ideal for high-stress gears and mechanical fasteners.
POM Copolymer: Features zero centerline porosity in thick blocks, better resistance to hot water/steam, and superior chemical resistance to strong alkalis.

2. Why is POM preferred over Nylon (PA) for precision wet or submerged components?

Nylon readily absorbs water and moisture from the air (up to 8%), causing parts to swell and lose critical tolerances. POM has a virtually zero water absorption rate (<0.2%), meaning its dimensions and mechanical fitment remain completely unchanged even when submerged in water or operating in high-humidity marine environments.

3. What tightest tolerances can you hold for custom turned POM gears and bushings?

Because POM cuts cleanly like metal without flexing, our Swiss CNC turning and 5-axis milling centers routinely hold tight tolerances down to ±0.01 mm (±0.0004") on critical bearing diameters, internal threads, and gear tooth profiles.

4. Can custom POM parts be painted or glued?

POM has a naturally chemical-resistant, low-friction surface that makes standard painting or solvent gluing challenging. For assembly, we recommend mechanical fasteners, snap-fit joints, or specialized surface treatment (plasma etching) if chemical bonding is strictly required.

5. What file formats are needed for an instant POM machining quote?

Please upload your 3D CAD files in STEP (.stp / .step), IGES (.igs), or SolidWorks (.sldprt) format. For precision gear teeth specifications, internal thread pitch, or bearing fit tolerances, please also attach a 2D drawing in PDF or DWG format.