Rapid Prototyping — design guidelines
On a prototype the goal is to learn something quickly, so the right design decisions are different from production. It is usually worth relaxing tolerances and accepting a substitute material to get the part two weeks earlier.
Constraints specific to this process
These are the limits that come from this process in particular. The general rules on wall thickness, corner radii and hole depth apply on top of them.
| Parameter | Design to thisNo surcharge, no discussion needed | We can reachAchievable, but affects price or lead time | Where the limit comes from |
|---|---|---|---|
| Tolerance on a fit-check part | ISO 2768-m | ±0.02 mm on 2 features | Tightening only the mating features keeps the part in the fast lane. A drawing where everything is tight moves the job into the precision queue and adds days. |
| Material substitution | 6061 for any aluminium | Exact grade on request | We hold 6061 and 304 in stock in most sizes. A specific grade like 7075-T7351 or 17-4PH may add a week of material lead time for a single prototype. |
| Cosmetic finish | As-machined | Bead blast + anodise | As-machined ships the same day it comes off the machine. Anodising goes to an outside plater and adds three to five days regardless of quantity. |
| Quantity for a design iteration | 3 pcs | 1 pc | Programming and setup dominate the price of a one-off, so the second and third pieces cost a fraction of the first. Three gives you one to test to destruction, one to measure and one to keep. |
What we see go wrong most often
Recurring issues on the drawings that reach us. None of them are hard to avoid once you know to look for them.
- Designing the prototype with production tolerances and then being surprised by the price. Tell us which dimensions you are actually testing and we relax the rest.
General machining rules
The numbers that apply across every cutting process — wall thickness, radii, holes, threads, tolerances and cost drivers.
- Wall thickness
- Internal corner radii
- Holes and threads
- Pockets, cavities and undercuts
- Tolerances, text and surface callouts
- What actually drives the price
Every quotation includes a manufacturability review against these rules. If something in your model falls outside them, we tell you before you commit, not after the first article fails.
Not sure whether your part clears these limits?
Send the STEP file. A manufacturing engineer marks up anything that will be difficult and returns it with the quotation — no charge, no obligation.