3D printing opens many doors for hard to find, or expensive components - in either plastic or metal. In my career, I had often worked with 3D parts as they related to prototypes for high volume production of plastic parts and injection molding.
Three things to keep in mind - 3D (CAD) file formats, printing materials and post-print finish.
Materials -
https://www.3dnatives.com/en/plastics-used-3d-printing110420174/#!
I think a good application for 3D is the shift gate on automatics. When I see these, they (like mine) are often chipped and unsightly. When the driver overthrows or gets rough with the shift stick, these are brittle and don't handle the impact well. They chip.
Common 3D materials like ABS or ASA are OK - but they're not going to take a hit as well as a PET or Polypro both of which will be difficult to hold tight tolerance and to paint. To make difficult (crystalline) plastics more receptive to paint a pre-treatment of corona etch or plasma etch to increase surface "wetability" will be well worth it a small additional cost.
3D printing (or FDM, fused deposition modeling) is a dot, or filament, deposition process that is performed in layered steps. Thus the surface finishes are not smooth and will usually need at least a bit of hand sanding, or filling, for improved surface and cosmetic appearance prior to paint or plate.
https://www.3dnatives.com/en/3d-technologies/3D machines utilize step files or .stp that are converted from CAD files. The better the resolution of your .stp file and the resolution of your printer - the better the appearance (less hand work) and accuracy of your part. Not unlike printing an image. Not all 3D print systems are alike. Some are MUCH better than others. Ask sources about the resolution of their equipment and your material choices.
More -
https://3dprinting.com/filament/finishing-3d-printed-parts/A library of STEP and IGES files is a fantastic idea. THANKS mrfatboy
My point - Choose your 3D materials and sources wisely.
