Overview
POM-H (Polyoxymethylene Homopolymer), commonly known as Acetal Homopolymer or by the trade name Delrin®, is a high-performance engineering thermoplastic recognized for its exceptional strength, stiffness, fatigue resistance, wear resistance, and dimensional stability.
Compared with POM-C (Acetal Copolymer), POM-H offers higher tensile strength, greater rigidity, improved fatigue performance, and superior creep resistance. These characteristics make it an excellent choice for highly loaded precision mechanical components.
POM-H is widely used in:
- Precision Gears
- Bearings and Bushings
- Industrial Machinery Components
- Automotive Systems
- Conveyor Equipment
- Pumps and Valves
- Electrical Components
- Structural Mechanical Parts
Due to its metal-like mechanical performance combined with lightweight characteristics, POM-H is one of the most popular engineering plastics for precision engineering applications.
Material Specification
| Property | Value |
|---|---|
| Material Designation | POM-H |
| Full Name | Polyoxymethylene Homopolymer |
| Common Name | Acetal Homopolymer |
| Trade Name | Delrin® |
| Material Family | Engineering Thermoplastic |
| Density | 1.41–1.43 g/cm³ |
| Appearance | Natural (White), Black |
| Typical Manufacturing Methods | CNC Machining, Injection Molding, Extrusion |
| Standard Forms | Rod, Sheet, Tube, Pellets |
Chemical Composition
POM-H is composed of highly crystalline homopolymerized formaldehyde chains.
| Component | Function |
|---|---|
| Polyoxymethylene Homopolymer | Structural Matrix |
| Thermal Stabilizers | Heat Resistance |
| Lubricants (Optional) | Wear Reduction |
| Reinforcements (Optional) | Enhanced Strength |
Common variants include:
- Delrin® 150
- Delrin® AF (PTFE Filled)
- Glass Filled POM-H
- ESD POM-H
- Food Grade POM-H
Mechanical Properties
Typical Values
| Property | Value |
|---|---|
| Tensile Strength | 70–80 MPa |
| Yield Strength | 65–75 MPa |
| Elongation at Break | 20–40% |
| Flexural Strength | 95–120 MPa |
| Flexural Modulus | 2.8–3.5 GPa |
| Hardness | Rockwell M88–100 |
| Compressive Strength | 100–130 MPa |
Typical Mechanical Performance
| Property | Performance |
|---|---|
| Strength | Outstanding |
| Stiffness | Outstanding |
| Fatigue Resistance | Outstanding |
| Creep Resistance | Outstanding |
POM-H generally provides higher mechanical performance than POM-C.
Physical Properties
| Property | Value |
|---|---|
| Density | 1.41–1.43 g/cm³ |
| Water Absorption (24h) | 0.20–0.35% |
| Saturated Water Absorption | 0.8–1.0% |
| Thermal Conductivity | 0.30–0.36 W/m·K |
| Electrical Resistivity | >10¹⁴ Ω·cm |
| Specific Heat Capacity | 1500 J/kg·K |
POM-H maintains excellent dimensional stability due to its very low moisture absorption.
Thermal Properties
| Property | Value |
|---|---|
| Melting Point | 175–180°C |
| Glass Transition Temperature | -60°C |
| Heat Deflection Temperature | 110–125°C |
| Continuous Service Temperature | -40°C to 105°C |
| Short-Term Service Temperature | Up to 140°C |
POM-H offers slightly higher thermal performance than POM-C.
Strength-to-Weight Ratio
| Material | Density (g/cm³) | Tensile Strength |
|---|---|---|
| POM-H | 1.42 | 75 MPa |
| POM-C | 1.41 | 65 MPa |
| PA66 | 1.14 | 90 MPa |
| Aluminum 6061 | 2.70 | 310 MPa |
POM-H provides excellent structural efficiency while remaining lightweight.
Wear Resistance
| Property | Performance |
|---|---|
| Abrasion Resistance | Excellent |
| Sliding Wear Resistance | Excellent |
| Surface Durability | Excellent |
| Bearing Performance | Outstanding |
POM-H is frequently used in gears, bearings, and high-cycle mechanical assemblies.
Friction Properties
| Property | Value |
|---|---|
| Coefficient of Friction | 0.20–0.35 |
| Self-Lubricating | Yes |
| Dry Running Capability | Excellent |
| Noise Reduction | Excellent |
The low-friction surface helps reduce wear and maintenance requirements.
Fatigue and Creep Resistance
| Property | Performance |
|---|---|
| Fatigue Resistance | Outstanding |
| Creep Resistance | Outstanding |
| Long-Term Load Capacity | Excellent |
| Dynamic Performance | Excellent |
POM-H is preferred for continuously loaded precision mechanical parts.
Dimensional Stability
| Property | Performance |
|---|---|
| Moisture Resistance | Excellent |
| Thermal Stability | Excellent |
| Precision Machining Capability | Outstanding |
| Tolerance Retention | Outstanding |
POM-H is widely used where tight tolerances must be maintained over time.
Chemical Resistance
| Chemical Environment | Performance |
|---|---|
| Oils & Greases | Excellent |
| Fuels | Excellent |
| Alcohols | Excellent |
| Hydrocarbons | Excellent |
| Solvents | Good |
| Weak Alkalis | Good |
| Strong Acids | Poor |
| Hot Water | Moderate |
Compared with POM-C, POM-H offers slightly lower chemical resistance but higher mechanical strength.
Electrical Properties
| Property | Value |
|---|---|
| Volume Resistivity | >10¹⁴ Ω·cm |
| Surface Resistivity | >10¹³ Ω |
| Dielectric Strength | 18–25 kV/mm |
| Dielectric Constant | 3.7–4.0 |
POM-H is widely used in electrical and electronic precision components.
Machinability
| Process | Rating |
|---|---|
| CNC Milling | Outstanding |
| CNC Turning | Outstanding |
| Drilling | Outstanding |
| Tapping | Outstanding |
| Routing | Excellent |
Machinability Comparison
| Material | Machinability |
|---|---|
| POM-H | Outstanding |
| POM-C | Outstanding |
| Nylon | Excellent |
| Polycarbonate | Good |
POM-H is one of the easiest engineering plastics to machine into precision parts.
Injection Molding Characteristics
| Property | Rating |
|---|---|
| Moldability | Excellent |
| Surface Finish | Excellent |
| Flow Characteristics | Excellent |
| Production Efficiency | Excellent |
| Dimensional Accuracy | Outstanding |
POM-H is widely used in precision injection molded components.
International Equivalent Grades
| Standard | Equivalent Grade |
|---|---|
| ISO | POM-H |
| ASTM | Acetal Homopolymer |
| DIN | POM-H |
| JIS | Polyacetal Homopolymer |
| GB/T (China) | 均聚甲醛（POM-H） |
| UL | Acetal Homopolymer |
Available Forms
| Product Type | Availability |
|---|---|
| Rod | Yes |
| Sheet | Yes |
| Tube | Yes |
| Pellets | Yes |
| Injection Molded Parts | Yes |
| Machined Components | Yes |
Typical Applications
Industrial Machinery
- Precision Gears
- Bearings
- Bushings
- Rollers
- Wear Components
Automotive Industry
- Fuel System Parts
- Window Mechanisms
- Door Lock Components
- Gear Assemblies
Electrical Industry
- Connectors
- Switch Components
- Insulators
- Precision Electrical Parts
Medical Industry
- Instrument Components
- Equipment Mechanisms
- Structural Parts
Packaging Industry
- Conveyor Systems
- Guide Rails
- Wear Strips
Consumer Products
- Mechanical Assemblies
- Sporting Equipment
- Appliance Components
Manufacturing Characteristics
| Manufacturing Process | Rating |
|---|---|
| CNC Machining | Outstanding |
| Injection Molding | Outstanding |
| Extrusion | Excellent |
| Secondary Assembly | Excellent |
Advantages
Highest Strength Among Standard Acetals
Offers superior mechanical performance compared with POM-C.
Outstanding Fatigue Resistance
Ideal for continuously moving components.
Excellent Wear Resistance
Suitable for gears, bearings, and sliding systems.
Low Friction
Provides self-lubricating characteristics.
Excellent Dimensional Stability
Maintains precision over long service periods.
Outstanding Machinability
Perfect for CNC-machined precision components.
Limitations
Lower Chemical Resistance Than POM-C
Less resistant to hot water and aggressive chemicals.
Possible Centerline Porosity
Thicker extruded sections may exhibit centerline porosity.
Limited UV Resistance
Outdoor applications may require UV stabilization.
Acid Sensitivity
Strong acids can degrade the material.
Comparison with Common Engineering Plastics
| Property | POM-H | POM-C | PA66 | PEEK |
|---|---|---|---|---|
| Strength | Higher | Good | Excellent | Outstanding |
| Fatigue Resistance | Outstanding | Excellent | Excellent | Outstanding |
| Wear Resistance | Excellent | Excellent | Excellent | Outstanding |
| Chemical Resistance | Good | Better | Good | Excellent |
| Machinability | Outstanding | Outstanding | Excellent | Good |
Comparison with POM-C
| Property | POM-H | POM-C |
|---|---|---|
| Tensile Strength | Higher | Lower |
| Stiffness | Higher | Lower |
| Fatigue Resistance | Better | Excellent |
| Chemical Resistance | Lower | Better |
| Hydrolysis Resistance | Lower | Better |
| Porosity | Higher | Lower |
Available Surface Finishes
Standard Finishes
- Natural Finish
- Black Finish
Functional Finishes
- CNC Machined Finish
- Precision Ground Finish
- Polished Finish
Specialty Grades
- Delrin® AF
- Glass Filled POM-H
- ESD POM-H
- Food Grade POM-H
- PTFE Filled POM-H
Frequently Asked Questions (FAQ)
What is POM-H?
POM-H is an acetal homopolymer engineering plastic known for outstanding strength, stiffness, wear resistance, and fatigue performance.
What is POM-H used for?
Typical applications include:
- Precision Gears
- Bearings
- Bushings
- Automotive Components
- Industrial Machinery Parts
What is Delrin®?
Delrin® is the most well-known commercial brand name for POM-H acetal homopolymer.
Is POM-H stronger than POM-C?
Yes. POM-H generally offers higher tensile strength, stiffness, and fatigue resistance.
Can POM-H be machined?
Yes. POM-H is considered one of the best engineering plastics for CNC machining.
Why choose POM-H?
Because it combines:
- Outstanding Strength
- Excellent Fatigue Resistance
- Superior Wear Resistance
- Low Friction
- Precision Machinability
Is POM-H suitable for gears?
Yes. POM-H is widely used in precision gear applications because of its low friction and excellent fatigue performance.
Does GCNOV provide POM-H manufacturing services?
Yes. GCNOV provides:
- POM-H CNC Machining
- Delrin® Machining Services
- POM-H Injection Molding
- Precision Plastic Fabrication
- Prototype Development
- Low-Volume Production
- Mass Production
- Mechanical Component Manufacturing