Specification sheets for plastic gears, bearings and wear parts are full of abbreviations. This guide translates the dimensions, grades and tolerance classes into decisions you can actually make.
Use it as a working checklist when you write your next enquiry.
This category covers a family of products rather than a single item. In practice a buyer defines plastic gears, bearings and wear parts by three things: the base resin, the format or dimension, and the performance or certification level it has to meet. Typical options in this category include plain and self-lubricating grades; module 0.3 to 8; bore tolerance H7 to H9. Materials most often specified are Polytetrafluoroethylene, UHMWPE, Polyoxymethylene, Polyamide, and the choice between them changes stiffness, temperature resistance, chemical behaviour and price.
In the medical and healthcare sector the decision is usually driven by biocompatibility and sterilisation stability, with full traceability as a secondary requirement. Typical end uses include diagnostic consumables, syringe barrels, implant trial components.
The table below summarises the values that usually decide the material choice.
| Material | Density | Tensile strength | Service temperature |
|---|---|---|---|
| Polyether Ether Ketone | 1.32 g/cm³ | 90-100 MPa | -50°C to 250°C |
| UHMWPE | 0.93-0.94 g/cm³ | 30-45 MPa | -150°C to 80°C |
| Polyoxymethylene | 1.41 g/cm³ | 60-70 MPa | -40°C to 100°C |
Polyoxymethylene is frequently the default selection here: POM is the standard replacement for small metal parts that must hold tight tolerances.
Typical values for a general purpose grade are listed below; filled, stabilised and speciality compounds will differ.
When you read a supplier quotation, check that the dimension, the resin grade, the colour reference and the tolerance class are all stated. A quotation that only gives a price per piece is not comparable between suppliers.
Beyond the base resin, most suppliers offer UV stabilised, food contact, flame retardant, anti-static and recycled content versions of the same product. Ask which additive package is included, because it is often the difference between a part that lasts three years and one that lasts ten.
Processing method drives both cost and performance, so it should be fixed early in the design.
Secondary operations such as printing, welding, machining and assembly are often cheaper to do in the same factory, and they reduce the risk of mismatch between components.
Work through these points in order and most specification mistakes disappear.
Send this list to your supplier with the drawing and you will receive comparable quotations from every factory you contact.
Standard production tolerance follows the relevant ISO or DIN tolerance class for the process; tighter tolerances are possible after machining or grinding, but they add cost. Define the tolerance only on the functional dimensions.
Yes. Standard samples are normally free of charge and shipped within three working days; custom samples are charged at cost and credited against the first production order.
Standard packing is export cartons on fumigation-free pallets, with custom labelling, barcode and retail packing available. We also handle consolidated containers and door to door delivery.
We can provide ISO 9001 quality system documentation, material certificates, RoHS and REACH statements, and where applicable food contact, flame retardancy or drinking water approvals. Tell us your target market and we will match the document set.
A new tool typically takes 25 to 45 days depending on cavity count and complexity, followed by T1 samples within one week. Existing tools can usually start production within 10 to 15 days of order confirmation.
Share your specification and quantity with us and we will recommend the most cost effective material, tooling route and packing method for your market.
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