r/startups • u/ohjaohneohjaoder • 22h ago

I will not promote Any hardware startups here that used Injection Molding for the prototype? (I will not promote)

Hey,

Many parts for a hardware prototype can be created using 3D printing. But for parts that are subjected to mechanical stress 3D printing isn't good enough.

Has anyone here had plastic parts injection molded for a prototype? How much did you spend on it (not just the injection mold, but all costs)? I've read about cheap 3D printed molds. Has anyone experience with these regarding the quality of the molded part and the cost?

Thanks!

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u/leshake 19h ago edited 19h ago

SLS can print very strong materials. PA11CF and PA12CF are super strong and nylon 12 is usually good enough. A good FDM can print some pretty strong parts cheaply as well. Injection molding is generally what you go for when you start small batch production.

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u/WalkerYYJ 18h ago

Printed parts to make molds for epoxy or super low volume injection.

That said that was 10 years ago. Printing has gotten a lot better, lots of newer technologies etc today vs when we were doing this stuff.

The biggest issue for most outfits isn't necessarily cash for the molds its the time it takes to iterate a design. For the cost of two or three steel molds you can buy a pretty good printer that can shoot protos out a lot faster than any injection company could ever turn new tooling arround to say anything of total turn time for an order.

That said in my opinion you should budget (time and $$) to do atleast one iteration of injection tooling once you start moving to scale.

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u/TriRedditops 12h ago

I was sending away for 3d printed prototypes and I had many design iterations to go through. Eventually I bought a Formlabs printer and cut my proto costs and timeline tremendously.

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u/leshake 5h ago

If you want to iterate on a design with injection molding CNCed aluminum is usually cheaper.

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u/jkerman 18h ago

Protomold is pretty great to work with. They’ll help you turn your part into a mold and make small runs of the part. It’s… not cheap but it’s not as expensive as you might think….

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u/PolarityInversion 13h ago

There are so many different processes available to make functional strength parts. It really depends on what your requirements are. Cast urethane is the closest you'll get to an injection molded part, and you can tailor the urethane used to your application. I like to DLP print a master part, touch up with filler and sanding to make sure it's perfect, then make a silicone mold and cast a bunch of urethane copies. I use a lot of BJB products, but there are countless companies out there selling the same thing. Their YT channel has lots of good howtos: https://www.youtube.com/@bjbenterprises/videos