Prototyping and iteration

Why iteration beats getting it right first time

Most design faults are not visible on a screen. A bracket that is clearly stiff enough in a model rings under vibration. A housing that assembles perfectly in CAD cannot be assembled by a person with two hands. A cover fits and then fouls the thing next to it. A spanner will not reach the rear bolt.

These are found by holding the part, offering it up, and seeing what is wrong with it — and each of them costs almost nothing to fix at prototype stage and a great deal to fix later. The point of a printed prototype is not that it is a finished part. It is that being wrong stops being expensive.

The industrial mount job on this site is exactly this: many versions printed, more expected, a design being arrived at rather than handed over. It is the least photogenic part in the gallery and the clearest example of how the work runs.

What a round looks like

Start from wherever you are. A finished STL, a solid model, a dimensioned drawing, a sketch, or a conversation about what the part has to do. None of these is the wrong starting point, and no file is required to begin.

Print, and print what matters. A prototype does not have to be the whole thing. Where only one interface is in question, printing that section is faster and cheaper and answers the question just as well.

Hold it and be honest about it. The most useful feedback is specific: this is too tight, this flexes, this is unreachable, this is the wrong way round.

Revise from the last version, not from scratch. The model is kept and versioned between rounds, so revision five starts where revision four finished. What changed between versions is recorded, because by the ninth nobody reliably remembers what the fourth was for.

Keep the printing constant. Same material and same settings between versions unless there is a reason to change one, so that when a prototype behaves differently the design is the reason and not the printing.

Checking a design before it is committed

Two things beyond printing are available, and both are described here exactly as far as they go.

Simulation is available where it helps — comparing two ways of doing something, or checking an approach is sound before committing to it. It gives you direction early, which is often exactly what a design decision needs. Because a printed part is layered, the confirmation then comes from the part itself: simulation points, test fitting proves. Used in that order you know precisely what each answer rests on.

Destructive testing can be arranged for smaller parts — loading and impact, at small scale. It is a controlled and genuinely informative check for the kind of duty these parts see. It is a workshop check sized to the duty these parts actually see. Where a part carries the level of consequence that calls for certified testing to a published standard, the quote points you to a testing house and the right manufacturing process — the useful answer at that stage.

What a printed prototype tells you

A printed part answers a specific and valuable set of questions extremely well, and it is worth knowing which ones so you get the most out of each round.

Fit, clearance and assembly. Whether it goes together, whether the fasteners are reachable, whether it fouls the thing next to it. These are the failures that cost the most to find late and almost nothing to find here.

Ergonomics and feel. How it sits in the hand, whether the grip is right, whether a control falls where a person expects it.

Behaviour and proportion. Whether a mechanism moves the way the model suggested, and whether the thing is the size you pictured.

Prototypes here are printed in PLA, PETG or flexible TPU, chosen to suit the question you are asking. Where a production part will be made in a different material or by a different process, we set the prototype up to answer the geometry question cleanly and tell you which findings carry across — so a round of prototyping always ends with something you can act on.

Your design stays yours. Anything you supply is used for your job alone. Where we model for you, the model comes with you — see the file policy.

Who this suits

Businesses developing a product or a piece of equipment, engineers working through a design, and anyone whose next decision depends on holding the thing. Funded development with several rounds ahead of it is the best fit, and it is welcome as ongoing work rather than a series of unrelated orders.

Minimum order is $75. Prototyping is cheap per round, not free per round, and knowing that up front saves everybody a conversation.

Frequently asked questions

How many rounds does a design usually take?

There is no useful average — it depends on how much is unknown at the start. What matters is that each round is cheap and fast enough that the number stops being the thing you are optimising. A design that takes six rounds and ends up right is a better outcome than one that takes two and does not.

Can you print just part of my design?

Yes, and it is often the right call. If only one interface, one bracket or one section is in question, printing that alone is faster and cheaper and answers the same question.

Do you keep my model between revisions?

Yes. It is kept and versioned so a revision starts from the last one rather than being rebuilt, and what changed between versions is recorded. Your files are never reused for anyone else.

Can you tell me if my design will be strong enough?

Yes, in the ways that matter at this stage. Simulation indicates whether an approach is sound, destructive testing at small scale shows how a printed version behaves under real loading and impact, and test fitting proves it on the actual part. You will get a clear account of what each check demonstrates, so you know exactly what you are relying on.

What if I only have an idea, not a file?

That is a normal starting point. One of the jobs on this site began with nothing but a conversation — see the pump housing case study.