I copied this from another long thread to preserve it as a separate searchable topic.
2363 doesn’t have a CNC router, and we lost our laser cutter. We now use our 3D printer to help make flat parts quickly. Let’s say we have a part like this that we want to make from lexan.
We cut a couple pieces of scrap to the rough size of the template, layer the template and the 2 pieces together in a stack using screws through the two larger nubs, which are sized for a #10-32 tap drill. Then locate the other holes by match drilling through the stack with a 1/8" drill. Then bandsaw, belt sand and file the parts to the perimeter of the template. Finally, separate the parts and open up the located holes to their final sizes on the drill press. WIth the template in hand, we can knock out a couple parts like this in 30 minutes or so. Not quite the rapid turnaround like when we had our laser cutter, but way faster than hand layout. And more accurate than using a paper template.
Yes. The tape seems to shift around under load, and can be a pain to clean off afterwards. Then there are the times when it just doesn’t hold and the pieces come apart. My experience is that the parts come out nicer when held by screws. Often you can even pick a pair of holes that are going to be in your finished part anyways.
We do similar steps for polycarb and small aluminum plates. Sometimes we can lay the parts out on our manual mill for the holes and finish the outside with a saw and sander. We also keep the printed templates in the pit. It’s a great thing to show the judges
I haven’t tried in a load bearing environment, but my 3d printer can do polycarbonate. With 100% infill and maybe a post print bake to improve layer adhesion, I wonder what the comparable strengths would be.
my gut feeling is more than strong enough for anything that is not getting hit by things outside of the robot. you simply cant replace the elasticity of 1/4" polycarb sheet.
A more sophisticated version of this would be use a handheld router (for small parts like these, perhaps a trim router or a dremel) and design the 3D printed template so that its walls are offset by the radius of the router. This would let the parts be cut in one go, instead of the iterative process or bandsawing, sanding, and filing.
You can get flush-cut router bits which allow the template to be actual sized (as I mentioned previously, this is a common technique in woodworking). Lots of videos showing how – here’s one: https://www.youtube.com/watch?v=mpzIZfFzkUE
The flush cut router bits use a bearing as the guide and you can get the bits with bearings at the top or the bottom which gives you options in regards to whether you want your template at the top or bottom (I seem to prefer the template on the top for some reason - mostly so I can watch the following action of the bearing and they work really well if you are using a router table where the router comes up from underneath).
I’m sure @john3928 is hip to that but I wanted to mention it in the event it might be useful for other people.
I general, this is a super solid idea - I print a lot of templates for just these sorts of purposes; drilling, cutting, scribing, whatever. A 3D printer is really useful for this and I love what the OP @ToddF is doing.
It takes more skill and care, but you can get great results with paper. Here’s a prototype belt reduction drive from 2020 where the plates were entirely hand-fabricated in HDPE this way. Tools used were a laser printer, a center punch, a cordless drill (with step bits for the larger holes), and a bandsaw. (A custom shaft and standoffs were made on a manual lathe.) It worked great; the robot got an exact copy machined in aluminum.
For our prototyping phase, I 3D print or laser cut hole template plates the students can drill holes exactly where we need them on metal extrusion. Seems like this works better than measuring no matter how much time they spend trying to align/centerpunch
