Hey, I recently wrapped up a project that I took on to get some experience with using 3D printing to make molds. The project went pretty well so I figured I’d share the steps in case anyone else is interested in trying it.
Step 1: Initial prototype. The “client” provided 2D graphics and general size descriptions, which I used to start a CAD model. I printed a few versions at a smaller scale to get iterations out of the door as quickly as possible.
Step 2: Final prototype. Once the design was finalized, I printed a full size prototype at a higher quality.
Step 3: Silicone mold making. I used Smooth-On Oomoo 30 (along with foam board and too much hot glue) to cast molds around the final prototypes. The silicone cures in 5-6 hours, at which point I could cut a parting line and carefully remove the prototype. The PLA model released from the mold without damaging any of the small details.
Step 4: Liquid plastic casting. I used a two part urethane resin to make the castings, it cures in about 15 minutes. Upon removal from the molds, I could see that the casting was “eating” some of the silicone details - no worries, I can always make more molds from the original printing.
Step 5: Contrast color casting. I poured a white urethane resin onto the cast part to fill the lines with a contrasting color.
Step 6: Finishing and sanding. I finished the models by sanding away the lines leftover from the printing process. Once the outer white layer was sanded off, the contrasting lines showed the underlying pattern exactly as it had been on the original drawing.
Anyway, if anyone has any comments, questions, or tips let me know - I’m planning on trying more projects with this method now that I have a little more experience with the process. (The final product was a set of custom beer tap handles designed to match a local brewery’s design style)
San Francisco, CA