Plastic Worm Gear | POM & Nylon, Module M0.2–M2.0, Self-Lubricating Drive

Product Overview

The physics of worm gear self-lubrication is specific to polymer materials: POM (polyacetal) and PA66 nylon contain no free oil, yet their low coefficient of friction — POM dry COF approximately 0.10–0.25 against steel — sustains low-wear sliding in the sealed mesh zone without any external lubricant. This property directly addresses the maintenance problem common in miniature drives: a sealed gearbox where the internal gear mesh is inaccessible after assembly. Metal gears in the same installation require oil or grease loaded at assembly; if that lubricant is displaced, migrates onto optical components, or dries out over time, the drive fails. A POM worm set avoids this failure mode entirely for light-duty cycles. Korea Ever-Power Worm Gear Co., Ltd supplies these plastic worm gears from module M0.2 to M2.0 in POM and nylon PA66, matched to bore diameters and outer diameters for specific drive assemblies.

Standard Dimensional Specifications

Product Samples & Application Reference Data

The three matched sets below illustrate the range from miniature camera drives to automotive actuators and valve controls. All dimensions and weights are from production datasheet records.

POM vs Nylon — Which Material for Your Application

POM and nylon are both called "self-lubricating plastics," but they behave very differently as gear materials. Selecting the wrong grade causes premature wear, dimensional drift, or unexpectedly high motor current — none of which show up until the drive has been assembled and tested. Understanding the material differences at the engineering level prevents these failures.

Plastic vs Metal Worm Gears — Engineering Comparison

This comparison is framed for the design engineer deciding between plastic and metal at the module M0.4–M2.0 scale. Generic comparisons that ignore the operating conditions of a specific product category are not useful. The rows below address the actual trade-offs that determine the correct material choice.

Application Deep-Dive — Four Drive Scenarios Where Plastic Worm Gears Outperform Metal

The following four scenarios are chosen because they appear repeatedly in actual customer enquiries. Each has specific engineering reasons why plastic is the right choice — and one clear boundary condition where metal would be necessary instead.

Design Checklist — Specifying Plastic Worm Gears Without Costly Errors

Engineers new to plastic gear specification encounter the same avoidable errors. The checklist below covers the five most common mistakes seen in plastic worm gear procurement.

• ⚑Ignoring the moisture absorption difference between POM and PA66. If your bore tolerance is H7 at Ø3 mm (±0.012 mm tolerance band), PA66 can swell 0.06 mm at equilibrium — five times the total tolerance. Use POM for bore fits below Ø6 mm unless the temperature requirement exceeds +100°C.
• ⚑Over-specifying torque margin for plastic. Designers familiar with metal gears often apply a 3× safety factor. Plastic gears are correctly rated using S-N fatigue data, not ultimate strength. A 30% torque margin above the sustained rating is appropriate; 300% drives unnecessary upsize to metal at unnecessary cost.
• ⚑Not accounting for thermal expansion. POM's coefficient of thermal expansion (110 µm/m·°C) is roughly 5× that of steel. At an operating temperature range of −20°C to +80°C (100°C span), a Ø10 mm gear body changes diameter by ≈0.11 mm. At M0.5, this is a meaningful fraction of tooth height — it must be verified that the mesh does not bind at the upper temperature limit.
• ⚑Skipping prototype validation before mold commitment. A plastic injection mold for a non-standard gear costs $3,000–$15,000 USD depending on complexity and cavity count. A CNC-machined or handmade prototype for $20–$100 catches fit errors, bore alignment problems, and assembly sequence issues before that investment is made. Do not skip this step.
• ⚑Using sulfur-containing EP gear oil with POM or PA66 gears. Extreme-pressure additives based on sulfur or chlorine chemically attack polyacetal and some nylon grades, causing stress cracking at the bore and degradation of the tooth surface. If a light gear oil or PTFE grease is added at the mesh, confirm it is free of sulfur and chlorine EP additives. Most PTFE-based and silicone greases are compatible.

Manufacturing Capability

Korea Ever-Power produces plastic worm gears by CNC machining for prototype quantities and injection molding for production volumes. Handmade precision-ground prototypes are used for initial fit verification before the production mold is cut. NC gear hobbing machines, NC gear shapers, and CMM measurement equipment support production quality control.

Related Components

A plastic worm gear works in tandem with a worm shaft to form the core of a low-noise, low-maintenance drive stage — well suited for light-load applications where metal gearing would be excessive. When a compact, enclosed drivetrain is required, pair it with one of our worm gear reducers, which provide a pre-aligned housing, integrated shafting, and consistent center distances right out of the box.

Worm Shaft — The mating drive element that engages directly with the plastic worm gear. Hardened steel shafts ensure durability even as the plastic gear absorbs shock and reduces noise.

Worm Gear Reducer — A fully enclosed unit combining the worm shaft, housing, and output stage. Use when precise mounting, sealed lubrication, or a higher second-stage torque output is required.

Frequently Asked Questions

How do I calculate the gear ratio for a plastic worm drive?

Ratio = wheel tooth count ÷ worm start count. A 1-start worm (single-lead thread) with a 30-tooth wheel gives 30:1. At 600 RPM motor input, output is 600 ÷ 30 = 20 RPM. For a 2-start worm with 30 teeth: ratio is 15:1, output would be 40 RPM. Single-start worms give higher ratios per stage and stronger self-locking behavior; multi-start worms give higher efficiency but weaker self-locking. In these POM/nylon sets, single-start designs covering 10:1 to 80:1 are standard.

What bore tolerance should I specify for a POM gear on a steel shaft?

For a press-fit assembly, specify H7/p6 (interference fit: shaft is 0.006–0.026 mm larger than bore at Ø3 mm). For a sliding-fit with set screw, use H7/h6 (clearance fit: bore is 0–0.012 mm larger than shaft). POM's low modulus (approximately 2.6 GPa) means an interference fit that would be rigid on a metal gear may allow slight slip under torque — add a flat on the shaft or a D-shape bore for positive torque transmission above 0.01 Nm. We machine to the tolerance you specify; confirm the fit class when ordering.

What is the expected service life of a POM worm gear in an IP camera drive?

In a typical pan-tilt camera cycling at 20 positions per hour, 16 hours per day, 365 days per year — approximately 116,800 cycles/year — POM at M0.4, 30T, running dry at 0.005 Nm output has shown more than 1,500,000 cycles before measurable tooth wear in controlled endurance testing. Real-world camera drives running at this duty level should see 3–5 years of service before tooth clearance exceeds the design tolerance. The primary wear mode is abrasive loss of the sliding tooth face; the wear rate increases if the mesh zone accumulates dust or abrasive particles — keep the housing sealed.

Can a CNC prototype be made before I commit to a production mold?

Yes — this is strongly recommended. Korea Ever-Power produces handmade or CNC-machined prototypes from your drawings or samples. Sample fees range from $2 to $100 per piece depending on complexity and tolerance level. Freight is on the buyer's account. Sample fees are credited on the bulk production order. Typical prototype lead time is 5–10 working days from confirmed drawing. The prototype allows you to verify bore fit, mesh engagement, noise, and motor current before any tooling investment.

Can the worm and wheel be made in different materials within the same set?

Yes — mixed-material pairs are common. A brass worm paired with a POM wheel takes advantage of brass's dimensional stability and worm accuracy while keeping the wheel light and self-lubricating. A steel worm with a nylon GF30 wheel gives higher load capacity with less noise than an all-steel pair. When ordering a mixed set, specify the material for each component separately and provide the operating torque, speed, and temperature range so we can confirm the pairing is appropriate before production.

Is there a minimum order quantity?

Standard catalog sizes (M0.2–M2.0 in POM) accept small trial quantities — even single-digit quantities for prototype builds. Custom ODM mold tooling is costed separately and amortized over a production run agreed at quotation. We are flexible for new OEM customers in development who need small initial quantities to validate their design before a volume commitment.

Customer Reviews

Packing & Shipping

Inner packing: individual PE bags with anti-static protection for sensitive polymer parts. Outer packing: rigid carton or wooden case depending on quantity. Modes of delivery: DHL, FedEx, TNT, UPS for international express. Sea freight for production volumes arranged on request. Customized packing per OEM customer requirements accepted.