Injection Molded Nylon Gear

Quiet PA Gear for Compact Transmission Systems

The injection molded nylon gear provides smooth torque transfer in mechanisms where noise, component weight and lubrication access require close control. PA nylon has a naturally low-friction surface, allowing meshing teeth to run with less operating noise than many metal alternatives. Its low density also reduces rotating mass, which can ease the load on small motors, shafts and supporting bearings.

The gear body, hub, bore and tooth profile form in one molding cycle. This production route supports detailed tooth geometry and repeatable dimensions without machining every gear from solid stock. Product and tooth-profile tolerances can reach ±0.02 mm under confirmed mold, material and inspection conditions.

Tooth Profile Control and Material Conditioning

Gear performance depends on pitch accuracy, tooth spacing, root shape and bore concentricity. The mold cavity must reproduce these features consistently while allowing the molded part to release without damaging the tooth edges. Cooling balance also matters because uneven shrinkage can change roundness or create local variation across the gear profile.

PA resin absorbs moisture, making material drying an important step before molding. Controlled preparation reduces silver streaks, bubbles and dimensional variation. Molding pressure, holding time and cooling settings are adjusted around gear diameter, wall thickness and hub structure.

The design can include keyways, D-shaped bores, splines, reinforced hubs or molded mounting details. Optional glass-fiber reinforcement may raise rigidity for higher loads, while unfilled PA retains lower friction and quieter running characteristics.

Technological Process

1. Mold Design & Fabrication: Optimize tooth profile structure based on drawings and manufacture high-precision gear molds to ensure tooth profile accuracy and consistency.
2. Material Preparation & Drying: Select PA raw materials and dry them to prevent defects such as air bubbles and silver streaks during injection molding.
3. Precision Injection Molding: Melt materials at high temperature, inject into molds under high pressure, and form the main body of the gear in one piece.
4. Deburring & Trimming: Remove gates and burrs, and finely trim the tooth profile and inner hole to ensure smooth and jitter-free transmission.
5. Surface Treatment (Optional): Conduct polishing, lubricating coating and other treatments as required to optimize transmission performance.
6. Full Inspection & Delivery: Inspect product dimensions, tooth profile accuracy and appearance, then pack and deliver qualified products.

Core Advantages & Applications

Common Applications

• Office Equipment: Transmission gears for printers, copiers and scanners
• Home Appliances: Internal transmission components for washing machines, air conditioners and small home appliances
• Automotive Electronics: Transmission gears for window regulators, seat adjusters and wipers
• Industrial Automation: Small transmission mechanisms, conveyor line equipment and precision instrument transmission systems

Daily output can reach 100,000 pieces after the mold and molding parameters enter stable production. Inspection focuses on tooth profile, bore size, concentricity, overall dimensions and visible molding defects. The finished injection molded nylon gear can also undergo meshing, rotation and assembly checks to confirm quiet movement and consistent engagement within the intended drive system.

Specification Table