Manufacturing guy-at-large.

Work-ish: 3D printed dropout protectors

Added on by Spencer Wright.

I think Nick Pinkston has it absolutely right: "3D printing is great, but it's only a small part of the solution." The current hardware revolution is about the workflow from development to manufacturing to distribution. Sure, I'm sure I'll have more and more 3D printed objects in my life in the next 5-10 years. But the effects of product customization (which will be significant) and kanban/just-in-time manufacturing (which I believe will be huge) will far outweigh the designer's ability to neglect draft angles when designing plastic parts. In the near future, I expect we'll be buying more stuff that hasn't been built yet than we have since the industrial revolution. In the next decade, I expect Amazon (or whomever) to be literally building the parts required to fulfill my order the night after I place the order. 3D printing will be a big part of this process, but so will distributed manufacturing and rapid delivery systems. And innovative ways of finding new products (and, on the flipside, innovative ways of finding new customers) will totally change the game.

I tend to recoil at most of the crap that's made with the current generation of FDM machines, but I've spent some time recently trying to think of objects in my life that I would accept being shat out of a MakerBot. A few traits I was looking for:

  • Needs to be made out of plastic
  • Needs to be disposable
  • Needs to have a rough surface quality (low layer resolution)
  • Needs to be something that's hard to find in a brick-and-mortar store
  • Relatively low part mass, to reduce print time & cost
  • Low dimensional accuracy to accommodate all sorts & conditions of printers
  • Bonus points if I wouldn't want to buy it from Amazon due to package quantity, lead time, etc. 

I'm sure there are better use cases, but one thing I came up with was dropout spacers. When shipping a bike, you usually remove the front wheel and install a dropout spacer into the fork. The spacer protects the dropouts from impact from below and also protects the fork from impacts from the side. Most consumers don't keep dropout spacers around, and wouldn't necessarily think to go to a bike shop to pick some up (most shops give them away) when they're shipping their bike. When the bike is unboxed on the other end, the spacers usually go straight to the trash, and surface finish is totally inconsequential. Plus, the spacer itself isn't very massive, and the dimensional accuracy required is low.

I spent an hour or two modeling, and got Shapeways to print me the result for $13. It's a bit more than I would want to pay for a piece of plastic, but the FDM version would be basically free. The finished version is shown below. I rather like it, and think that things like it will be printed - not in the home, probably, but by brick-and-mortar third party services like Kinkos, or web shopping platforms like Amazon and Shapeways - as a matter of course in the future.

If anyone is interested in printing one of their own, I'd encourage them to grab the model on the Thingiverse. I also published the model and a bunch of other stuff in a GitHub repository


Inventor and Shapeways.

Inventor & Shapeways. SLA parts from Shapeways tend to have a bunch of powder slag in any crevises; this one was packed full. 

Picking out SLA dust.

Back to front: Injection molded rear dropout spacer; injection molded front dropout spacer; my SLA front dropout spacer.