If you need plastic parts for tuning, vehicle refinement or a small special series, you probably already know the problem. The big injection-moulding suppliers are geared to six- and seven-figure quantities. For a few hundred or a few thousand parts, you usually get a rejection there – or no answer at all. Through online platforms you’ll quickly find some Chinese supplier, sure. But finding the right one, having the tool properly designed and, in the end, holding dimensionally accurate parts in your hands on time – that is an entirely different matter. That is exactly where we come in.
Why a small series in injection moulding is a case of its own
In injection moulding, the big cost block is in the tool, not in the individual part. In a large series, that block is spread over millions of shots and barely matters. In a small series, it is spread over a few hundred parts. That changes the calculation completely – and with it the question of which tool even makes sense in the first place.
For tuning and small-series parts we therefore mostly rely on aluminium tools or simply hardened steel tools. A fully hardened production tool would simply be over-dimensioned here. The aluminium route is cheaper and faster: instead of many weeks, tool-making often takes only days to a few weeks. The tool life is easily enough for a few hundred to several thousand parts. So why tie up capital in a tool built for millions of shots when you need a few thousand parts?
The right materials for interior and exterior
Which plastic fits depends on the installation location and the load. For automotive parts we work, depending on the requirement, with materials such as:
- ABS and PC/ABS for interior trims, covers and visible parts where the surface has to be right
- PP for robust functional parts that need to be chemically resistant
- PA (polyamide), often glass-fibre reinforced, for mechanically loaded parts such as brackets or structural components
- PBT, when dimensional accuracy and temperature stability matter
- ASA or UV-stabilised grades for exterior parts that have to cope with sun and weather
With exterior parts in tuning, the choice of material is especially delicate. A component that yellows or warps after one summer becomes a complaint case. That is why we clarify UV resistance, heat-deflection temperature and surface before the tool is released. Afterwards, it can only be corrected at high cost.
The fit has to be right
An add-on part that sits three millimetres off is not something you can sell. With refinement and tuning parts, the fit to the existing production body is more important than for almost any other component. That is why we work with clean 3D data from the very start, define tolerances and reference points and check the fit on T1 samples (initial sample inspection) before series production starts. If something doesn’t fit, the tool is reworked. A correction loop on the sample is always better than an entire series that doesn’t fit in the end.
Quality can be assured
“Made in China” on its own says little about quality – in either direction. What matters is which plant you work with and how tightly the process is managed. We work with plants in the IATF 16949 environment, define the inspection characteristics in advance and have the critical dimensions checked and documented. How we secure quality across the entire supply chain is described in more detail on our page about quality management.
From practice: plastic parts for a G-Class tuning specialist
A specialist for high-end vehicle refinement in the off-road segment came to us with exactly this kind of task: plastic add-on parts in a manageable quantity, high demands on fit and surface, and a schedule that had to be reliable. For a mass supplier it was too small, for importing on their own it was too risky. We selected the right plant, supervised the tool design, checked the samples and steered the series through a fixed point of contact in Germany. For the customer it was, in the end, simply an order placed with a German partner. We took care of the time difference, the language and on-site control.
Why a German-speaking partner makes the difference
The price advantage from China is quickly gone again if the tool is wrongly designed, samples are shipped back and forth for weeks, or the whole series doesn’t fit in the end. We sit between you and the plant. We translate your requirement into a technically clean specification, find the right plant and steer the project to clear deadlines through our project management. And you have a point of contact in Germany who is reachable in your time zone and in your language. If need be, on a Saturday too – because that is when production runs in China.
Injection moulding is just one part of what we source from Asia. For an overview of carbon, plastic and metal components, see our parts sourcing page.
Have a plastic part in mind?
Whether it’s a single part, a small series or a recurring requirement: send us your idea, a sketch or your 3D data. We’ll tell you honestly whether and how it can be sensibly realised. Send your enquiry now.
Further reading: Why we consistently rely on steel and aluminium tooling, and how to secure sourcing in China, is covered in the linked articles.
