What are rapid prototyping services, in practice?
A rapid prototyping service makes a physical version of your idea fast enough that you can learn from it before you commit to anything bigger. On PrintCommons that usually means a local fabricator with a 3D printer, a laser cutter or a CNC machine who can turn your file or sketch into a part, often in days rather than weeks. How fast depends on the shop, the process and how busy they are.
The point is not a perfect part. It is an answer. Does the lid close? Is the handle comfortable? Do the holes line up with the bracket? You find out by holding it, and you find out cheaply when the part is a rough one.
Which process fits which stage?
Early prototypes answer questions about shape and size. Later ones answer questions about strength and finish. The process you choose should follow the question.
- Early, looks and fit: 3D printing is usually the quickest way to get a three-dimensional shape in your hands. Plain plastic is fine at this stage. See custom 3D printing service.
- Flat parts, panels, brackets and enclosures made from sheet: laser cutting gives crisp outlines from a 2D drawing, and sheet pieces can be assembled into boxes and frames. Which materials work depends on the machine. See laser cutting service.
- Later, strength, tight fits and real materials: CNC machining cuts from solid stock, so the part is made of the material you plan to use. It suits parts that will carry load or need accurate dimensions. See CNC machining service.
- Anywhere a design needs a printed or cut surface to judge colour and graphics, a fabricator may offer vinyl or UV printing as a service. Ask.
A prototype made by one process does not behave exactly like a final part made by another. A printed bracket and a machined one can fail in very different ways. Treat early results as guidance, then check again with a part made closer to the final method.
How do I iterate without wasting money?
Change as little as you can between rounds. If you alter the size, the thickness and the hole spacing all at once, and the new part works, you will not know which change mattered. If it fails, you will not know which one broke it.
- Print only the part of the design you are testing. A small section with the tricky joint is quicker than the whole assembly.
- Use the cheapest material that answers the question. Save the good material for the version you plan to keep.
- Skip finishing on early rounds. Sanding and painting a part you will throw away teaches you nothing.
- Number your versions and keep a note of what changed. Name the files v1, v2, v3.
- Order two copies when you can. One to test to destruction, one to keep as a reference.
Cost depends on material, machine time, setup and how much hand work a part needs, so ask each fabricator what drives theirs rather than guessing.
What should I tell the fabricator about my goal?
Most people send only a file. Add a few lines about what the part is for, and the fabricator can often save you a round. A person who knows the work will spot a problem a file will not show.
- What question the prototype answers: fit, comfort, appearance, strength, assembly.
- What it will touch or carry. Heat, weight, water, sunlight, repeated movement.
- What it must connect to, with the dimensions of the other part.
- Which dimensions matter and which do not. A hole that takes a bolt matters. The curve of a handle may not.
- How many you need and how soon.
- Whether this is round one of several, so they can price and plan for it.
If you only have a sketch or a description, that can still be enough to start. 3D print an idea covers what to send when you have no model yet, and get a design 3D printed covers file formats and common file problems.
What goes wrong with early prototypes?
- Judging strength from the wrong process. A printed part that snaps does not always mean the design is weak. It may mean the printing direction or material was the problem. Ask the fabricator.
- Tolerances that were never agreed. Two parts that fit on screen can be tight or loose in real life. Tell the fabricator how snug the fit should be, and expect to adjust.
- Too many changes in one round, as above.
- Going straight to the expensive process. A cheap, ugly part would have shown the same mistake.
- No plan for the next step. If you may need fifty of these later, mention it now.
Safety-critical parts are a separate matter. If a failure could hurt someone, a quick prototype is not a test. Tell the fabricator what the part does and follow their advice, or have a qualified person look at it.
How do I get started?
Write down the question your first prototype should answer, collect your file or sketch with measurements, and message a few fabricators. Custom parts made near me shows how to describe a part so any fabricator can quote it, and how orders work explains what happens once you agree on a price. When you are ready, find a fabricator or browse the marketplace.