POM Ball | Acetal Ball | Delrin Ball | 5mm to 310mm | Precision Dimensioned
Delrin® is the registered brand name for acetal homopolymer (polyoxymethylene or POM-H) manufactured by DuPont. In mechanical engineering, Delrin balls (acetal homopolymer spheres) are highly regarded for their outstanding stiffness, high mechanical strength, dimensional stability, and resistance to fatigue. Unlike PTFE, which is soft and prone to deformation under continuous mechanical loads (cold flow), Delrin POM-H detent balls remain rigid and resilient, making them ideal for load-bearing applications like bearings, water regulation valves, sliding rails, detent pins, and fuel system check valves. Delrin absorbs minimal moisture, allowing it to maintain critical dimensions in wet or humid environments.
Applications
Fuel System Check Valves
Resists gasoline, diesel, and biofuels, providing a rigid, spring-loaded seal.
Load-Bearing Bearings
Used as spherical rolling elements in light-duty conveyor rollers and sliding mechanisms.
Pneumatic Control Valves
Provides high-cycle check sealing in air compressors and pneumatic manifolds.
Water Regulation Devices
Low moisture absorption prevents swelling, keeping valve operations precise in plumbing lines.
Furniture Drawer Slides
Smooth-rolling, quiet Delrin balls used in drawer tracks and industrial cabinet guides.
OEM Mechanical Switches
Acts as spring-loaded detents and positioning elements in mechanical rotary switches.
Features
High Stiffness
High mechanical rigidity and tensile strength resist deformation under constant mechanical load.
Low Moisture Absorption
Excellent dimensional stability in humid or wet fluid handling environments.
Fatigue Resistance
Superior resilience makes them suitable for high-cycle check valves and bearings.
Low Coefficient of Friction
Coefficient of friction of 0.20 to 0.25 ensures clean, smooth operation in dry assemblies.
Chemical Resistance
Excellent resistance to fuels, hydrocarbons, solvents, and neutral aqueous solutions.
High Impact Strength
Absorbs shocks and impact loading without cracking or chipping.
Precision Machining
Rigid structure allows machining to tight spherical tolerances.
Lower Cost
More economical material choice compared to premium fluoropolymers like PTFE or PEEK.
Technical Specifications
| Property | Value |
|---|---|
| Material | POM (Polyoxymethylene / Delrin / Acetal) |
| Diameter Range | 5mm – 310mm |
| Grade | ISO 3290 Grade G10 |
| Temperature Range | -40°C to +100°C |
| Moisture Absorption | 0.2% — highly dimensionally stable |
| Tensile Strength | 60 – 70 MPa |
| Specific Gravity | 1.41 – 1.43 g/cm³ |
| Color | White (natural) or Black |
| Chemical Resistance | Oils, fuels, solvents, neutral solutions |
| Export Markets | UAE, Germany, USA, Japan, Singapore, Brazil, Turkey, Middle East |
Available sizes
We manufacture Delrin (POM) balls in a wide range of metric and fractional inch sizes. Below are typical dimensions we supply.
| Size | Metric | Inch | Tolerance |
|---|---|---|---|
| 1/4″ | 6.00 mm | 0.250″ | ±0.03 mm |
| 3/8″ | 9.52 mm | 0.375″ | ±0.03 mm |
| 1/2″ | 12.70 mm | 0.500″ | ±0.04 mm |
| 3/4″ | 19.05 mm | 0.750″ | ±0.04 mm |
| 1″ | 25.40 mm | 1.000″ | ±0.05 mm |
| 1-1/2″ | 38.10 mm | 1.500″ | ±0.08 mm |
| 2″ | 50.80 mm | 2.000″ | ±0.10 mm |
Manufacturing Process
Resin Selection
Premium DuPont Delrin (POM-H) or high-grade POM copolymer resins are used to avoid internal porosity.
Extrusion Molding
Acetal resins are extruded into dense solid rods with controlled cooling to minimize internal stress.
Thermal Annealing
Extruded acetal blanks undergo an annealing cycle to relieve stress, ensuring dimensional stability.
Precision Lathe Turning
Blanks are CNC turned and centerless ground to achieve roundness and a polished surface finish.
Inspection
Sphericity and surface roughness are verified in our inspection room using digital metrology tools.
Material comparison
Compare Delrin POM balls against PTFE balls to select the appropriate option for your application.
| Characteristic | Delrin (POM) | PTFE |
|---|---|---|
| Mechanical Stiffness | Excellent (high load capacity, resists deformation) | Low (soft, subject to creep/cold flow under load) |
| Maximum Operating Temp | Up to +120°C continuous | Up to +260°C continuous |
| Friction Coefficient | Low (0.20 - 0.25) | Extremely Low (0.04 - 0.10) |
| Cost Profile | Highly Economical (lower raw material cost) | Premium Sourcing Cost |
Compliance & Standards
IEC registered. ISO 3290 Grade G10. POM (Acetal) and Delrin (DuPont brand) equivalent grades available. Note: not recommended for strong acid service — for chemical resistance, use PTFE or PEEK Balls (both available from HEMSUN). Regular export to UAE, Germany, USA, Japan, Singapore, Brazil, Turkey, and Middle East.
Frequently Asked Questions
What is the difference between a POM Ball and a Delrin Ball?
Delrin is DuPont's brand name for a specific Acetal Homopolymer (POM-H). POM (Polyoxymethylene) covers both homopolymer (Delrin-equivalent) and copolymer (POM-C) variants. Both offer similar precision dimensional properties. We manufacture POM/Acetal/Delrin-equivalent Balls from 5mm to 310mm.
Why are POM Balls preferred for precision valve and flow meter applications?
POM's very low moisture absorption (0.2%), high surface hardness, and dimensional stability make POM Balls the preferred choice where tight diameter consistency across humidity and temperature variations is critical — such as precision ball valve seats, flow meter float balls, and fuel injector check balls.
What is the largest POM Ball you manufacture?
We manufacture POM/Delrin Balls up to 310mm diameter — one of the widest size ranges for POM Balls available globally.
What is the main advantage of Delrin over PTFE balls?
Delrin offers much higher stiffness, mechanical strength, and creep resistance. It is better suited for load-bearing rolling elements and high-pressure check valves.
Are Delrin balls chemical resistant?
Yes, Delrin has excellent resistance to hydrocarbons, fuels, neutral solvents, and basic solutions, but it is attacked by concentrated mineral acids and oxidizing agents.
What is the difference between POM-H (Delrin) and POM-C (Acetal Copolymer)?
POM-H (Delrin) offers higher tensile strength, stiffness, and hardness, whereas POM-C (Copolymer) provides better hydrolysis resistance and lower centerline porosity.
Do Delrin balls swell in water?
Delrin absorbs very little moisture (around 0.2% to 0.25% at saturation), making it extremely stable in water compared to nylon, though not as completely hydrophobic as PTFE.
Are Delrin balls food safe?
Yes, specific grades of Delrin are FDA compliant and are widely used in commercial food preparation and milk dispensing equipment.
What tolerances can you hold on Delrin balls?
We hold standard tolerances of ±0.03 mm to ±0.05 mm on standard diameters, and can achieve tighter tolerances on custom order runs.
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