Plastic Worm Gears for Micro Drives | POM & Nylon Gear Sets

Product Overview of Micro Plastic Worm Gears

Ever-Power supplies engineered plastic worm and worm wheel components sized for the quiet, low-torque drives that power consumer electronics, automotive comfort systems, and compact medical equipment. Our Korean customers mostly use these gears as direct replacements for Mabuchi, Nidec and Mitsumi proprietary parts, matching shaft diameter, tooth count and centre distance down to the hundredth of a millimetre, so the original motor brackets do not need to be re-tooled.

The core lineup covers Module 0.2 through Module 2.0 in POM (Polyacetal) and PA66 nylon, with bore diameters from Ø1.40 mm and lengths as short as 6 mm. A typical 30-tooth M0.4 worm wheel mated with a single-start RH worm weighs under 1 gram, which keeps rotor inertia low in stepper and BLDC applications. Typical industries include IP security cameras, automotive rear-view mirror adjusters, fax and multi-function printers, medical infusion pumps, and precision laboratory instruments.

Technical Specifications and Variant Data

The table below lists the baseline dimensional envelope shared by the plastic worm family. Tooling is already cut for the listed bore and module ranges, which typically shortens the lead time for repeat orders to under three weeks. Bore and outer-diameter values marked flexible can be honed to a customer print during finishing.

Below are three production references currently running on our moulding floor. Each row shows a typical gear train paired with its plastic worm, with the application confirmed by end users. Note how a change in rotation hand (RH vs LH) or pitch cone is usually all that separates one camera model from another.

How the Worm Drive Works in Micro Applications

A plastic worm gear converts rotary motion from a small DC or stepper motor into a high-reduction output that is both quiet and self-locking. The worm — a single- or multi-start thread cut onto a shaft — meshes with the worm wheel at right angles. Because the teeth slide rather than roll, contact is continuous and the drive produces less than 35 dB of noise at 3 000 rpm in a typical camera pan-tilt head, which is below the ambient noise of most server rooms.

When the worm has only one thread start and the lead angle is shallower than the coefficient of friction between the POM and nylon faces, the assembly is naturally self-locking. The motor can drive the load, but back-driving from the load side is impossible. For surveillance gimbals or mirror folding mechanisms this is exactly the behaviour the designer wants — the tilt angle stays put when power is removed, with no brake or encoder holding torque required.

Materials, Moulding and Post-Process Options

POM (Polyacetal) is the first-choice resin for more than eight out of ten plastic worm assemblies we ship. It has a low coefficient of friction against steel shafts, dimensional stability within ±0.02 mm over a −30 °C to +90 °C service window, and enough crystallinity to resist creep under continuous low-duty loads. PA66 nylon is specified when the drive runs damp, greasy, or at slightly higher torque, because its toughness and impact resistance are better at the cost of a 0.3 % water-absorption swell that has to be accounted for in the tooth backlash.

• ◇POM homopolymer (TEPCON_M90-10): baseline for camera and printer gears, running dry or with a trace of PTFE grease.
• ◇POM + 20 % glass fibre: upgrade option for higher shock loads or mirror motor gears that see minus-temperature cold starts in winter.
• ◇PA66 + MoS₂: self-lubricating compound for valve actuators and lab instruments where regreasing is not practical.
• ◇Food-grade POM (FDA): used in coffee machines, vending equipment and small food-dispensing pumps.

Ever-Power runs in-house 50-ton and 80-ton electric injection presses with a climate-controlled tooling shop, so first-article dimensions track the CAD print to within ±0.02 mm. Short-run hand-machined prototypes from bar stock are available before mould cutting, which lets Korean clients validate the gear train in a real product before committing to tooling costs.

Measured Performance and Backlash Data

The numbers below are typical measured values from our QC lab, taken on a 30-tooth M0.4 POM worm wheel mated with a single-start steel or plastic worm, 100 % duty at 25 °C. They should be read as a typical range rather than a contractual guarantee for every lot.

Drive efficiency drops noticeably as the reduction ratio climbs above 60:1, which is the point where a two-stage design or a switch to a metal worm gear reducer usually makes more sense than stretching the plastic gear set further.

How to Select the Right Plastic Worm Set

Specifying a plastic worm set is less about squeezing extra torque and more about matching the gear train to the rest of the mechatronic package. Five inputs decide most of the decision:

• 1Target reduction ratio. Single-start worms cover 20:1 up to 60:1 comfortably. Above that, consider a two-stage layout or a metal assembly.
• 2Peak and continuous torque. A 30-tooth M0.4 POM worm wheel handles about 0.15 N·m continuous and 0.4 N·m peak.
• 3Shaft-to-shaft centre distance. This is the hardest-to-change dimension later. Lock it early, then size module and tooth count around it.
• 4Operating temperature and humidity. POM drifts 0.05 mm per 10 °C; nylon swells with humidity. Pick the resin that keeps backlash in range.
• 5Self-locking requirement. If the mechanism must hold position with power off, choose a single-start worm with a lead angle below 5°.

Send a stamped drawing or the damaged original part — our reverse-engineering team measures it on a Mitutoyo CMM and quotes a drop-in replacement within two working days.

Worm Gear Types Compared: Non-Throat, Single-Throat, Double-Throat

Most plastic gear sets are built on the non-throat geometry because the straight cylindrical profile is the easiest to mould and eject cleanly. Understanding the three families helps when an engineer is deciding whether to upgrade a light-duty plastic assembly to a throated metal set later on.

Because plastic gears rarely run above 0.5 N·m, the simpler non-throat layout is almost always enough. If the application calls for heavier loads the conversation usually shifts toward a bronze worm wheel on a steel shaft, which is a different product family entirely.

Related and Complementary Drive Components

Plastic worm sets rarely ship alone. Korean OEMs often buy them bundled with a matching motor pinion, a ground steel worm shaft, and a packaged self-locking worm gearbox for the heavier output stage of the same machine. Our broader catalogue covers the jump from 0.2 g plastic gears all the way up to 5 kg cast-iron industrial reducers, which keeps purchasing simple when one mechanical assembly spans multiple torque levels.

Browse the full range through our worm gear sets catalogue, or contact the technical desk in Seoul for a co-engineered solution. For heavier industrial needs, the packaged worm gear reducer family covers 10 N·m to 3 000 N·m output torque in standard housings.

Frequently Asked Questions

Q: Which plastic holds up better when the drive sees occasional water splash?

PA66 nylon performs better than POM in damp environments because its surface recovers faster from water contact. However, PA66 absorbs roughly 0.3 % of its weight in humidity, so the design must tolerate the resulting dimensional swell at the mesh.

Q: Can you cut a plastic worm wheel for a centre distance that is not a standard value?

Yes. Centre distance, bore and length are all tunable during finishing. Send the print with tolerance bands and we quote against it. Most custom centre distances are produced from existing tooling by changing inserts, which keeps NRE under USD 400.

Q: How do I verify that the incoming gears match the drawing before assembly?

Every production lot ships with a CMM inspection report covering tooth thickness, bore diameter, outer diameter and runout. Korean customers who need a full PPAP package can request it at the time of PO — lead time adds roughly five working days.

Q: What is the smallest module you can reliably mould?

M0.2 is the practical floor for injection-moulded plastic worm gears. Below that, tooth accuracy drops and demoulding damage becomes a real risk. For sub-M0.2 work we recommend machining from POM bar stock instead.

Q: Do you offer material certification for medical-device use?

Yes. FDA-grade POM and USP Class VI nylon are both held in stock. Material certificates of conformance (3.1) accompany the shipment, and RoHS and REACH statements are included in the standard documentation pack.

Q: What is a realistic lead time to Incheon port for 5 000 pieces?

For a repeat part, 18 to 22 working days ex-factory plus 3 days sea freight to Incheon. A new tooling build adds 25 to 35 days depending on module and cavity count.

Q: Is lubrication required, or can the gears run dry?

POM on steel can run dry for light-duty intermittent use. For continuous operation we recommend a synthetic grease with a PTFE additive applied once at assembly, which typically lasts the full service life of a camera or printer drive.

Customer Voices from Korea and Neighbouring Markets

Kim Min-jae, Mechanical Design Engineer, Incheon (late 2025)
"We were replacing a discontinued Mabuchi gearhead in a 2 MP pan-tilt camera line. Ever-Power reverse-engineered the 30T M0.4 POM wheel from a broken sample and quoted back in two days. First articles measured within 18 µm on tooth thickness — right in the middle of the drawing tolerance. Six months later we are on the fourth repeat order."

Park Ji-hoon, Automotive Tier-1 Buyer, Gyeonggi-do (mid 2025)
"Our rear-view mirror folding module was failing in winter cold starts. Ever-Power suggested moving from standard POM to a 20 % glass-filled grade. Same tooling, new resin. Field warranty returns dropped from roughly 1.2 % to under 0.3 % over the winter season. Straightforward engineering, no pushy sales talk."

Sakura Ito, Procurement Specialist, Osaka (early 2025)
"Small order, ten units of a custom M0.5 worm for a laboratory dosing pump. Most Chinese suppliers refused because the quantity was too small. Ever-Power machined them from bar stock, shipped in 12 days, and priced them fairly. That flexibility is the reason we kept coming back — we are now on the third reorder for a production run."

Choi Seo-yeon, Plant Engineer, Busan (late 2024)
"We use them in food-dispensing machines on ferries, so hygiene matters. FDA-grade POM with matching certificates was the reason we switched. The gears have been running 14 hours a day for eight months without a single replacement. Noise stayed well below what the original nylon parts produced."

Nguyen Van Hung, Factory Maintenance Manager, Hanoi (early 2026)
"Replacement gears for three lines of packaging machines. We needed fast delivery — the plant cannot afford downtime. Ever-Power shipped the first air parcel in nine days and the bulk follow-up by sea. Price was about 30 % lower than the original Japanese OEM part, and dimensional fit was exactly the same."

Yoon Ha-eun, Medical Device R&D, Seoul (late 2024)
"Specifying gears for an infusion pump is painful — every dimension is scrutinised by the regulator. Ever-Power delivered a full material pack including biocompatibility summaries on the first shipment, which saved weeks of back-and-forth in our submission."