High Impact Resistance Derlin Gear Pom Plastic Star Wheel Plastic Gear

High-impact-resistance POM (Delrin / Polyacetal / Polyformaldehyde) plastic star wheels — also called POM star gear wheels or POM transmission wheels — are multipurpose toothed or pointed-star-profile wheels machined or injection-moulded from POM engineering plastic. POM (full name: Polyformaldehyde) is widely known as "plastic steel" due to its outstanding combination of mechanical properties: wear resistance, high hardness, low friction coefficient, excellent rigidity (high tensile elastic modulus), chemical stability, and dimensional stability. Korea Ever-Power's high-quality POM star wheels are available in natural colour or customised; size custom-made per drawing or sample; manufactured by injection moulding and CNC machining; ISO9001, SGS, FDA, RoHS certified. Sample order accepted; free injection sample after paying mould cost; 30-day mould + sample lead time; 10–30 days mass production.

Korea Ever-Power's POM star wheels are used in automotive industry (replacing brass half-shaft and planetary gears — improving service life and saving copper), electrical and electronic industry (low power consumption, high dielectric strength), and agricultural machinery (sprayer parts, planter joints, milking machine parts, irrigation housings, valves, joints, water bushings). POM can replace metals such as bronze, zinc, and tin in precision transmission applications.

POM Star Wheel

MC Nylon CNC

White Delrin

Black POM

High Rigidity — Tensile Elastic Modulus

POM has the highest tensile elastic modulus (stiffness) of any standard engineering thermoplastic — 2,500–3,200 MPa, vs 1,000–1,500 MPa for nylon at dry conditions. This rigidity means POM star wheels deflect minimally under tooth contact load — maintaining the tooth profile geometry under working loads. In precision transmission star wheels where the tooth profile directly determines the motion transmission accuracy (cam follower star wheels, bottle conveyor star wheels), POM's high stiffness is critical for maintaining positional accuracy throughout the service life of the wheel.

Wear Resistance and Low Friction

POM has excellent wear resistance and a low friction coefficient (μ ≈ 0.10 against steel, dry) — the lowest of any thermoplastic except PTFE and UHMW-PE. This combination of low friction and good wear resistance makes POM star wheels self-lubricating in light-to-medium duty applications — the POM surface provides adequate tribological performance against mating metal or plastic surfaces without grease or oil. For automotive transmission star wheels (replacing brass half-shaft and planetary gears), POM's wear resistance extends service life vs the brass components it replaces, reducing maintenance intervals and component replacement cost.

Dimensional Stability — Low Water Absorption

POM absorbs only 0.17–0.20% water at 23°C — among the lowest of engineering thermoplastics. This near-zero hygroscopic growth means POM star wheel tooth profiles remain accurate even in wet or humid environments (food processing, agricultural machinery, outdoor conveyors). In contrast, nylon absorbs 2–3% water, causing significant tooth profile growth that changes the meshing geometry and increases backlash — a problem that does not occur with POM star wheels. Dimensional stability also makes POM star wheels suitable for precision applications where tooth clearance is controlled to ±0.05 mm or tighter.

Chemical Stability

POM is resistant to most organic solvents, oils, greases, petrol, and hydraulic fluids — and to dilute acids and alkalis in the normal concentration range for industrial use. This chemical resistance makes POM star wheels suitable for automotive transmission environments (gear oil, ATF, petrol), agricultural machinery (fertilisers, herbicides, pesticides diluted for field use), and food processing (cleaning agents, food acids). POM is not suitable for concentrated strong mineral acids (sulphuric, hydrochloric, nitric) or phenols — Korea Ever-Power confirms chemical compatibility for specific applications.

High Heat Resistance for a Thermoplastic

POM maintains good mechanical properties up to 90°C continuous service — the highest operating temperature of standard commodity engineering thermoplastics. At 90°C, POM retains approximately 60% of its room-temperature tensile strength — adequate for light transmission loads in automotive interior and industrial equipment applications where elevated temperatures are encountered. For applications above 90°C, Korea Ever-Power offers PPA or PEEK star wheel alternatives with higher heat resistance.

Electrical Properties — Electronic Applications

POM has low power consumption (low dielectric loss factor), high dielectric strength, high insulation resistance, and high arc resistance — making POM star wheels suitable for electrical and electronic drive components where metallic parts would create short-circuit risks. In battery-powered devices, the low dielectric loss of POM gears avoids energy loss through the gear material itself under alternating mechanical stress — a minor but real advantage for maximum battery efficiency in precision electronic instruments.

Automotive — Replacing Brass and Metal

POM star wheels replacing brass half-shaft star gears and planetary gears in automotive differential and transmission mechanisms. POM's mechanical strength exceeds that of brass (tensile strength ~65 MPa for POM vs ~310 MPa for brass — but at lower weight and cost, and with sufficient strength for the specific loading). Korea Ever-Power's automotive POM star wheels save copper material cost, improve service life vs brass in corrosive environments, and reduce transmission weight — all commercially valued improvements in automotive driveline design.

Conveyor and Packaging Star Wheels

POM star wheels (also called bottle-sorting star wheels, timing star wheels, or conveyor indexing wheels) in beverage bottling lines, pharmaceutical tablet packaging machines, and food container handling systems. The star wheel's pointed profile engages each container or bottle at a specific angular position, controlling the spacing and orientation of products for downstream processing. POM's dimensional stability ensures consistent container spacing throughout the star wheel's service life.

Electrical and Electronic Industry

POM star wheels and precision gears in electrical meters (energy metering star wheel mechanisms), electronic circuit testers, transformer tap-changer mechanisms, and electrical switchgear position indicators. POM's combination of dimensional precision, wear resistance, and excellent electrical properties (high insulation resistance, high arc resistance) makes it the preferred plastic for electrical transmission components where metallic parts would create leakage or short-circuit risks.

Agricultural Machinery

POM star wheels in hand sprayer parts, planter joints, transport parts, milking machine drives, irrigation housing valve stars, water bushings, and seeder disc mechanisms. Agricultural POM components must withstand outdoor UV exposure, temperature cycling, soil particle abrasion, and repeated exposure to diluted agricultural chemicals — POM's outdoor stability and chemical resistance suit these demanding conditions. The self-lubricating property eliminates the grease maintenance that metal agricultural components require.

Medical Equipment

POM star wheels and transmission gears in diagnostic laboratory equipment, infusion pump drives, and analytical instrument positioning mechanisms. FDA-listed POM is biocompatible for indirect food/drug contact applications; the zero-lubrication operation eliminates contamination risk in sterile environments; and POM's dimensional precision maintains accurate dosing or sample positioning over the medical device's rated service life.

Precision Instruments

POM star wheels and cam follower gears in precision metering instruments, optical instrument focus mechanisms, laboratory pipette dispensers, and scientific instrument positioning drives. POM's combination of high rigidity, dimensional stability, low wear, and self-lubrication meets the demanding precision requirements of scientific instruments where gear backlash must be maintained within ±0.01 mm over the instrument's 10-year service life.

What is the difference between POM, Delrin, Acetal, and Polyacetal — are they all the same material?

Yes — POM, Delrin, Acetal, and Polyacetal all refer to the same material class (polyoxymethylene — a highly crystalline thermoplastic). Delrin is DuPont's trade name for POM homopolymer (POM-H); Acetal and Polyacetal are generic names; POM is the ISO abbreviation. There are two grades: POM-H (homopolymer — slightly higher strength and melting point) and POM-C (copolymer — slightly better chemical resistance and lower thermal degradation during processing). Korea Ever-Power uses POM-C natural as the standard grade for precision star wheels, and POM-H (Delrin 500P) for high-strength gear applications where maximum mechanical properties are required.

Can Korea Ever-Power make POM star wheels from customer artwork or sample without a full drawing?

Yes — Korea Ever-Power accepts customer artwork (2D drawing, 3D CAD file, or scan) or physical sample as the basis for producing custom POM star wheels. If only a sample is provided, Korea Ever-Power measures all dimensions (overall diameter, tooth profile, tooth count, bore, keyway, face width) and prepares a dimensioned drawing for customer approval before the mould design begins. This reverse-engineering service ensures the new POM star wheel matches the original part dimensions exactly. 30-day lead time from drawing approval to first injection moulded samples. Contact Korea Ever-Power with your sample or drawing.

"We supply spare parts for agricultural sprayer machines and ordered POM star wheel replacements from Korea Ever-Power based on our worn sample (no drawing available). Korea Ever-Power measured the sample and returned drawing in 4 days — all 12 dimensions confirmed correct. Mould and samples delivered in 28 days. Dimensional inspection of 10 sample pieces: all within ±0.03 mm of drawing dimensions. Field test comparison vs original brass star wheel: POM wheel showed zero measurable wear at 6 months vs 0.4 mm wear on brass. Chemical resistance to 2% copper oxychloride spray solution: no surface degradation at 12 months."

Kim Hyeon-su  |  Agricultural Spare Parts Manager, Incheon Agri-Parts Co.  ·  Q2 2026

"We manufacture beverage bottling line machinery and use POM black star wheels (6-point profile, OD 180 mm) from Korea Ever-Power in our bottle-spacing stations. Critical dimension: star point radius ±0.05 mm — determines bottle clearance at speed. Korea Ever-Power achieves ±0.03 mm in production. After 18 months at 24,000 bottles/hour: star point profile measured — maximum wear 0.09 mm across all 6 points. Zero bottle jams attributable to star wheel wear. Water absorption after CIP wash-down cycle: measured 0.02% — confirming dimensional stability through daily cleaning."

Lee Gyeong-min  |  Bottling Line Mechanical Engineer, Gyeonggi Beverage Machinery Co.  ·  Q4 2025