Machined Prototypes vs 3D Printed: When the Difference Matters
News
Rapid prototyping is not a different machine — it is a different priority. When a design needs to be in your hands to be tested, the job is judged on whether it answers the question, not on whether it is the cheapest way to make that geometry. That changes what we optimise for: getting the part machined from your CAD as directly as possible, flagging anything that would make the design unmanufacturable, and producing a part you can assemble, measure and put in front of a customer.
What we prototype
- Functional test parts for fit, assembly and mechanism checks
- Enclosure and housing iterations before tooling investment
- Jigs, fixtures and test rigs to support a production line
- Sales samples and pre-production units for customer approval
- Bridge parts that keep a line running while hard tooling is in progress
Machined prototypes versus printed ones
Additive processes are the right answer for some geometry, and we will say so. But for a part that has to be tested as a real component, machining has three advantages that matter:
- Material equivalence. A machined prototype can be made in the same grade as production — 6061, 316 stainless, POM — so the test result means something. A printed part in a photopolymer tells you about shape, not about strength, stiffness or thermal behaviour.
- Tolerance equivalence. Machined prototypes hold the tolerance the production part will hold, so fits and clearances measured on the prototype transfer to the production design.
- Surface and finish equivalence. Anodising, passivation and the other finishes in our range can be applied to a machined prototype, which is usually not true of printed parts.
Design feedback at the prototype stage
The most useful thing we do on a prototype job is tell you what will be difficult before it is machined. At drawing review we check tool access, wall thickness, corner radii, thread depth and tolerance stack-up, and flag anything that will either cost more than expected at production volume or fail in service. Catching it at prototype stage is free; catching it after tooling is not.
We quote within one business day of receiving a drawing, and a 3D model is enough to start the conversation.
Standard capability
| Item | What we work to |
|---|---|
| Tolerance | ±0.05 mm on machined features |
| Materials | Aluminium (6061, 7075), stainless steel, brass, steel, POM, PEEK, acrylic |
| Surface finish | As machined, anodising, sandblasting, blackening, PVD, plating, passivation |
| Order size | From a single prototype through to volume production |
| Quality system | ISO 9001 / ISO-TS 16949, in-house dimensional inspection |
How a prototype order runs
- You send the CAD model and tell us what the part is for — fit check, functional test, customer sample.
- We review for manufacturability, flag issues and quote within one business day.
- On approval the part is machined and inspected in-house before it ships.
- When the design settles, the same process carries over to production quantities.
Questions buyers ask
Can you work from a STEP file only?
Yes. A 3D model is enough to start. Where a dimension is functionally critical — a bore for a bearing, a mating face — we will confirm it with you rather than assume, because a model does not carry tolerance intent.
What if my design cannot be machined as drawn?
We tell you, with the specific feature and the reason, before quoting. Sometimes the fix is a radius, sometimes it is a change of process, and occasionally it is accepting a higher cost at volume. You get the information at prototype stage, when it is cheap to act on.
Do you sign an NDA?
Yes, on request. Send the drawing with a note and we will put the agreement in place before any files are reviewed.
Can prototypes and production be ordered together?
Yes, and it is often the sensible commercial route: the prototype proves the design while the production order is prepared against the same process and the same material specification, so the parts that arrive at volume match the part that was approved.