Several people have looked at me with surprise when I say I am make my own prototypes in my basement. The decision was purely a matter of cost.
When I started researching how to turn a thought into a prototype, I learned there are charlatans willing to take your money for the promise of a CAD (Computer Aided Design) file and a working prototype. You likely get the file for the reasonable price promised, but then have to come up with a lot more cabbage to actually get the working prototype. I got prototype bids, and could do the math pretty quickly:
4 sizes x 3 iterations (and it turns out I needed more) x cost per prototype = More money than I had for prototypes.
So, I just started researching on the internet, and ended up taking a free one-day class on making molds at Reynolds Advanced Materials. Reynolds, with locations in nine major cities, has done alright in the deal, as I have purchased almost all my materials from them. The process is best seen via this short YouTube video (1 minute 16 seconds):
o Verify you have a viable product at an acceptable cost – topic of another blog post
o Design your prototype plan and estimate the cost
o Find a CAD designer – these are typically people with engineering degrees. I found Rob Miller at Loophole, Industrial Designer, who has an office in my town, Denver. I like working locally when possible.
o Purchase and assemble 3D printer
o Obtain CAD files from the designer – these may also called STEP files. My designer uses SolidWorks, a very common CAD program. For each size\iteration, I had 3 mold files, as I needed to print a three-part mold. The three parts were the core, the front and the back.
o Use the software that came with the 3D printer to convert the STEP files to .gcode files that are read by my Creality 3D printer. Put the converted files on a mini disk.
o Insert the mini disk into the 3D printer.
o Print each of the three parts of the mold in turn.
o Spray each part of the mold with release agent – this is critical. Without release agent, I practically destroy my mold getting the part out.
o Clamp the three parts of the mold together. My mold included a funnel at the top where the silicone is poured.
o Mix silicone, pour into mold. Wait for silicone to cure. The amount of cure time required is specified on the silicone packaging.
o De-mold the prototype. This means using all my strength to pry the mold apart.
o Trim excess silicone off the prototype.
Gem of Wisdom: Be sure you know your prototype and manufacturing costs before moving forward with spending any money. Don't spend money you can't afford to lose.