3d printing vs injection molding

wondering what would be more cost effective, 3d printing knobs, or getting injection molds for knobs?

cost effective - 3d printing.
accurate - molds

Most 3D printers I've seen can't get the items as "smooth" as an injection mold.

/R

I'll bet that if you only want a few, 3D printing is more cost effective. Mold making is usually expensive. Then you have to make some and see if the mold is good. If not you start over...But if you need a whole bunch and will need a whole bunch more in the future get a mold made.

pucho812 said:

wondering what would be more cost effective, 3d printing knobs, or getting injection molds for knobs?

Click to expand...

Those two processes are not remotely similar wrt cost economics. per piece and/or per design. 

In fact, I ordered a pair of SLA prototypes  (a variant 3d printing process where a laser shoots into a liquid resin to harden it in layers to build a 3D model) to prove out my mechanical design before cutting metal on a tool base to make the IM tool for my current package.

3D may make sense for one off, and perhaps very low volume DIY designs. otoh the typical knob IM tool has 20 to 30 cavities or more. Tooling up full custom IM knobs made sense back when I worked at Peavey (using millions a year), now not so much.

JR

PS: My favorite full custom knob I tooled up, was not about the knob cosmetics. It was a pretty mundane looking knob for the fixed install market, but I tooled up a longer shaft behind the knob, so I could set the control element back far enough behind the faceplate to clear the pot shaft. That way the customer could selectively remove the knobs from just the controls that they didn't want the operator to have access to and fill those holes with a cosmetic cover (hole plug).  This was far cheaper than adding an expensive security cover and more flexible since you could protect just the individual controls you wanted to, and leave the others available to the operator.

Hmmmm...a security knob. I like it.

3d printing/sla etc. is good for prototyping to low volume production, as has already been said. But until the resolution gets up there (give it a coupe years, they're already 3d printing on the nano scale), round surfaces won't be as smooth as moulds.

3D printers and machines like that build the object in layers. So strictly speaking the surface quality will never be perfectly smooth. They will always require to be hand finished. Unless of course they come up with a post process for the final finish. 

During the peak of my modelmaking business ('99-00) I was offered contracts which required to invest into STL SLS etc. technology but I thought it was far too risky. Looking back it was a good move.

3d printing is not nearly as accurate for the low end machines compared to mold making. A cost effective solution could be to lease a roland modela for 100 usd a month (with the added perk that you can mill circuit boards) and make wax molds on that machine and then cast poly urethane molds in the wax then cast liquid plastic in the polyurethane molds.

greetings,

Thomas