Tips for 3D printing

When you want a custom plastic piece fast (and the design isn’t amenable to being made out of multiple flat laser cut pieces) then 3D printing is the way to go.

3D printing is actually a whole family of different processes: SLS, SLA, FDM, etc. They’re described in detail elsewhere, Wikipedia can get you started. The following steps are general for all of the different processes.

1. Find a 3D printing firm.

Just search on the Internet using the terms “3D printing” or “rapid prototyping”. Contact them, tell them who you are and that you’re looking for a 3D printing firm for your small, one-off jobs. Also ask if they’ll work from sketches or simple drawings. Most places are happy to take this kind of work, but in rare cases a firm will be more industrially focussed. We’ve used Quickparts, and have been quite pleased.

2. Pick a material.

There are a lot of different materials and processes to chose from. Some variables you’ll want to consider are: rigidity, resolution, and strength. Some materials are quite rigid, but have a tendency to crack and shatter under stress. Other materials will bend and flex, but not break. Some materials can hold a tapped hole, others will shatter if you try to drill into them. The best thing is to get a sample kit to help you decide.

3. Design your part.

Unlike laser cutting, for 3D printing, you need a real CAD file for the 3D printing firm. There are a bunch to chose from, here are some key options you should consider:
SolidWorks: Pro-level stuff. Educational discounts available. You probably won’t outgrow this program.
SketchUp: From Google. Basic version is free. There are a lot of tutorials online. The full version still isn’t as professional as SolidWorks.
Alibre: Recommended by Quickparts.

4. Order your parts.

You can typically upload your CAD file and order online. You can often elect to have the parts primed and painted if needed. Turnaround is typically a few days.

Other tips

Make it flat

The build time in 3D printing is largely a function of the thinnest dimension. In turn, the build time can affect where your job goes in the queue, and thus affects your delivery time as well. So if your part is flat, it will be fast to fabrication and you should get it quickly.

Pack it in

Making several parts in one go can be economical. So if there are some subtle variations you want to try, do them all in one go. Again, try to keep it flat, so the array’s smallest dimension is as small possible. You can ask the 3D printing firm what their maximum dimensions are in X and Y to design your array. If you need to, join them with thin branches so that you don’t get charged for multiple pieces, then cut them apart later.

Undersize the parts if painting

If you’ll be painting the part, don’t forget to undersize everything so that you’re accounting for the thickness of the paint. The 3D printing firm can estimate the thickness of the primer and paint.