Prototype in plastic first

A desktop 3D printer tests fit overnight for a few dollars of filament, before you pay for metal.

A $300 to $600 desktop printer, for example a Bambu Lab, turns the cost of being wrong from hundreds of dollars into a few cents of plastic. Print the part, hold it against the real object and see what is off.

Not everything prints at scale or in the final material, but fit, hole spacing, mounting points and clearances all transfer. Print only the interface region if the whole part is large.

Photograph the print next to the real object and feed the discrepancies back into your spec.

Checklist

• Print the interface regions at minimum
• Test fit against the real object
• Record every deviation in the spec