In automotive projects, custom injection moulded parts is only acceptable when the paperwork is right. This article maps the standards, test methods and documents you should ask for.
The notes below come from day to day production and export work with overseas buyers.
This category covers a family of products rather than a single item. In practice a buyer defines custom injection moulded 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 multi-cavity tooling; shot weight 1 g to 3 kg; tolerance class DIN 16901. Materials most often specified are Polyoxymethylene, Thermoplastic Elastomer, Glass Filled Nylon, Acrylonitrile Butadiene Styrene, and the choice between them changes stiffness, temperature resistance, chemical behaviour and price.
In the automotive sector the decision is usually driven by weight reduction and impact resistance, with heat stability as a secondary requirement. Typical end uses include lighting bezels, fluid reservoirs, bumpers and fascias.
These figures are typical for commercial grades and should be confirmed against the supplier's certificate for your specific lot.
| Material | Density | Tensile strength | Service temperature |
|---|---|---|---|
| Acrylonitrile Butadiene Styrene | 1.04-1.06 g/cm³ | 30-50 MPa | -20°C to 80°C |
| Glass Filled Nylon | 1.36-1.38 g/cm³ | 130-190 MPa | -40°C to 150°C |
| PC/ABS Alloy | 1.13-1.15 g/cm³ | 45-60 MPa | -30°C to 110°C |
Polypropylene is frequently the default selection here: PP is the lightest mainstream packaging resin and keeps its shape under repeated flexing.
Ask for the certificate number and test report, not just a claim of compliance.
Ask the supplier to state the standard number, the test method and the result on the certificate. A test report without a standard reference is difficult to defend during an audit.
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.
Each step below has its own control points, and skipping one of them is where most defects start.
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.
These are the criteria that actually predict whether the part will perform in service.
Send this list to your supplier with the drawing and you will receive comparable quotations from every factory you contact.
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.
For standard sizes and colours the minimum is usually one pallet or one production run; for custom tooling the economic minimum depends on the tooling cost amortised over the expected volume. Send us your annual volume and we will calculate the break even point.
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.
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.
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.
Our team supplies custom injection moulded parts to automotive customers worldwide, with samples, material certificates and full inspection reports available before mass production.
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