injection Plastic Parts customization

Injection plastic parts customization covers the full spectrum of engineering plastic gear and component production at Korea Ever-Power — from prototype single pieces through small batch trial production to full mass production. Materials available: ABS, PP, Nylon (PA6 / PA66), PC, POM (Delrin/Acetal), PU, TPU, TPV, PBT, PC+ABS, PE, UHMW-PE, MC Nylon. Weight range: 2 g to 2 kg per part. Customised per customer drawing (DXF, DWG, PRT, SAT, IGES, STEP) or sample. 100% inspection before shipping. OEM service available with 24-hour support and prompt reply.

Korea Ever-Power's injection plastic parts programme offers: high mechanical strength and good toughness with high tensile and pressure resistance; strict raw material selection for consistent production quality; fine dimensional control following drawing requirements exactly; a large mould inventory for standard specifications plus deep customisation capability for special requirements; and factory-direct supply with no intermediary mark-up. Applications: chemical industry, machinery, electric power, manufacturing, food processing, media, and mining industries.

Plastic Spur Gears

Plastic Helical Gears

Plastic Bevel Gears

Plastic Worm Gears

Plastic Internal Gears

Plastic Double Spur Gears

Nylon Spur Gears

Nylon Planetary Gears

POM Star Wheels

The Law of Gearing — Involute Tooth Profile

All production plastic gears at Korea Ever-Power use the standard involute tooth profile — the curve traced by a point on a taut string unwinding from a circle (the base circle). The involute profile satisfies the fundamental law of gearing: the common normal at the contact point between two meshing teeth must always pass through the pitch point. This condition ensures a constant velocity ratio between driver and driven gear regardless of centre distance variation — a critical property in plastic gears that expand with temperature and absorb moisture, both of which change the effective centre distance during operation.

Module, Pitch, and Tooth Count

The module m = pitch diameter / tooth count = 25.4 / diametral pitch. For plastic gears, the module is typically in the range M0.5–M5 for injection-moulded gears and M1–M16 for machined (hobbed) gears. The contact ratio ε — the average number of tooth pairs simultaneously in contact — must be ≥ 1.2 for smooth operation. At low tooth counts (< 17 teeth), undercutting of the tooth root becomes a concern: the hobbing cutter removes material from the tooth root, weakening it. For plastic gears with fewer than 17 teeth, profile-shifted gearing (positive addendum correction) shifts the tooth outward to avoid undercutting while maintaining the correct gear law.

Thermal Expansion and Backlash Allowance

Plastics have thermal expansion coefficients 5–10× higher than steel (POM: 100–120 µm/m·°C; steel: 12 µm/m·°C). A 50°C temperature rise in a 50 mm diameter POM gear causes a diameter increase of ~0.25 mm — which reduces the gear mesh backlash significantly. If the backlash is initially zero, thermal expansion causes the gears to jam. Therefore, plastic gears require 0.05–0.15 mm more initial backlash per pair than equivalent metal gears — and the housing design must accommodate the differential thermal expansion between the plastic gears and the metal housing.

Moisture Absorption — Nylon Dimensional Change

Nylon (PA6, PA66, MC Nylon) absorbs moisture from the environment — typically 2–4% by weight at equilibrium in 50% relative humidity. This moisture absorption causes dimensional growth: a PA6 gear that is 50 mm diameter when dry may grow to 50.5–51 mm at equilibrium moisture content. The moisture also plasticises the nylon, reducing stiffness but increasing impact resistance. Plastic gear designs using nylon must account for this dimensional change: the gear is typically designed at the dry state with extra backlash, and the centre distance is set for the equilibrium moisture state.

Self-Lubrication — The POM and Nylon Advantage

POM, UHMW-PE, and oil-containing MC Nylon gears are self-lubricating — they run dry (without grease or oil) in light to moderate duty applications. POM has one of the lowest dry-friction coefficients of any engineering plastic (μ ≈ 0.1–0.2 vs steel), allowing it to run against steel or other POM without external lubricant. Oil-containing MC Nylon is cast with mineral oil dispersed in the nylon matrix — the oil migrates to the surface during operation, providing continuous boundary lubrication. This self-lubrication eliminates the maintenance requirement for re-greasing in sealed or inaccessible drive housings.

Noise Damping — Plastic vs Metal

Plastic gears are significantly quieter than metal gears at the same speed and load — by 5–20 dB(A) depending on material, mesh frequency, and load level. This noise reduction comes from two mechanisms: the higher internal damping of plastics (loss factor tanδ ≈ 0.01–0.05 vs 0.001 for steel) dissipates the vibrational energy from tooth mesh impacts as heat rather than sound; and the lower elastic modulus of plastic (POM: 3 GPa vs steel: 200 GPa) reduces the stiffness of the tooth contact, which smooths the load impulse during tooth engagement — the primary source of gear noise.

Injection Moulding

CNC Hobbing

CNC Machining

MC Nylon Casting

POM Precision Machining

Large Diameter Machined

Product Design Centre

3D CAD design in STEP, IGES, DWG, DXF formats. Gear design calculation: module selection, tooth count, centre distance, backlash, contact ratio, and root bending stress verification for the selected material. Design optimisation for plastic-specific considerations: thermal expansion allowance, moisture absorption compensation, and mould draft angle requirements.

3D Printing Centre

Rapid prototype plastic gear parts in SLA, SLS, and FDM processes — delivering functional test pieces within 24–48 hours. 3D-printed prototypes allow customers to verify gear geometry, check housing fitment, and test basic functional performance before committing to injection mould tooling cost.

Precision Parts Machining

CNC gear hobbing, CNC turning, and CNC milling of plastic gears from rod, sheet, or cast MC Nylon stock. 150+ CNC and processing machines. Tolerances: 0.01–0.05 mm. Suitable for 1–500 pieces without mould tooling cost — the economical route for small-batch and prototype-to-series production runs.

Rapid Mould Production

Injection mould design and production for plastic gear tooling. Mould types: single-cavity (prototype), multi-cavity (volume production), family moulds (multiple gear sizes in one tool). Mould materials: P20 (medium volume), H13 (high volume), S136 (corrosive resins). Mould lead time: 15–30 days from drawing approval to first sample. 100+ mould stock for common gear sizes — often no new tooling required.

Injection Moulding Production

20+ injection moulding machines from 50T to 500T clamping force. Part weight range: 2 g–2 kg. Materials processed: ABS, PP, Nylon, PC, POM, PU, TPU, TPV, PBT, PC+ABS, PE, UHMW-PE. Process controls: melt temperature ±5°C, injection pressure ±2 bar, shot weight ±0.1 g — ensuring consistent dimensions across production run. 100% visual and dimensional inspection of first article and statistical sampling of production.

Testing Equipment (20+ Units)

Dimensional measurement: CMM, optical comparator, gear rolling test machine. Material verification: hardness tester, tensile tester (for material certification). Visual inspection: automated vision systems for surface defects, short-shots, and flash. 100% inspection before shipping — zero-defect delivery standard for all Korea Ever-Power plastic gear and injection plastic part orders.

What plastic material should I choose for my gear application?

The key selection criteria are: operating temperature (POM to 90°C; PA66 to 120°C; PC to 130°C); lubrication (POM and UHMW-PE self-lubricating; Nylon requires occasional lubrication unless oil-containing MC grade); environment (UHMW-PE for chemicals; stainless fixings needed with PA6 in damp conditions); load (MC Nylon for highest load capacity among plastics; POM for stiffness and precision); and cost (ABS lowest; MC Nylon highest). Korea Ever-Power's engineering team can advise on the correct material for your specific application — contact us with the operating conditions.

What is the minimum order quantity for custom injection plastic gears?

For CNC-machined or hobbed plastic gears (no mould required): MOQ 1 piece. For injection-moulded gears using existing mould tooling from Korea Ever-Power's mould stock: MOQ typically 100–500 pieces. For injection-moulded gears requiring new custom mould tooling: MOQ typically 1,000–5,000 pieces to amortise tooling cost. Contact Korea Ever-Power with your quantity requirement — in many cases, standard mould stock covers the required gear size without new tooling investment.

How do I submit a drawing for a custom plastic gear quotation?

Send drawings in DXF, DWG, PRT, SAT, IGES, or STEP format — or design from a customer-provided sample. Include: material specification, colour requirement, quantity, and any surface treatment requirement (electroplate, paint). If you have a sample gear without a drawing, Korea Ever-Power can measure and produce a drawing for approval before production. Contact Korea Ever-Power with your specification to begin — 24-hour service with prompt reply.

"We design packaging machinery and source custom POM and MC Nylon gears from Korea Ever-Power. Sent STEP files; received dimensional inspection report with first article — all critical dimensions within ±0.02 mm. POM gear tooth surface Ra: 0.8 µm as measured on our profilometer. Noise at 1.5 m from gearbox: 44 dB(A) — 11 dB lower than the steel gears we replaced. 18-month production run without a single warranty claim on the gear sets. Highly recommended."

Kim Hyeon-woo  |  Packaging Machinery Design Engineer, Incheon Automation Systems Co.  ·  Q1 2026

"We produce a consumer toy robot and needed injection-moulded ABS gear sets at 200,000 pcs/year. Korea Ever-Power supplied multi-cavity mould (8-cavity) from their mould stock — no new tooling cost. First article samples in 12 days. Shot weight consistency ±0.05 g across 20 consecutive shots. 24-hour reply confirmed when we had an urgent quantity increase before our peak season. Price 22% below our previous Taiwan supplier at equivalent quality."

Lee Min-jun  |  Toy Robot Product Manager, Gyeonggi Consumer Electronics Co.  ·  Q4 2025