3D Printing Experts in the House?

[annasea]

Who 3D prints here?

I have 2 very simple shapes I need duplicated. The potential cost in my case seems to be more in making the file than in printing, so I'd like to do that myself. It seems Tinkercad may be the way to go in my case. Mac friendly, no software to download... win-win.

What's the tolerance for measurements? Do most people need to file printed pieces to an exact fit? I'm guessing get as close as possible, but there are sprue marks as in lost wax casting to remove anyway, isn't there?

Any helpful advice will be greatly appreciated!

 

[Bob DBF]

The 3D printing guys are down in DIY.
3D Printing, Laser & CNC

 

[Boarderguy]

@The Chairman

 

[The Chairman]

Those are easy shapes to 3D print. The slower you print, the better the quality.

 

[annasea]

Those are easy shapes to 3D print. The slower you print, the better the quality.

What about creating files for them in something like Tinkercad, though? I can find a place to print them w/ no problem, but I need to create the digital files myself, otherwise they'll cost me a fortune. Is the learning curve for basic shapes such as these relatively reasonable? The only potential issue I see is accuracy of measurements... both need to fit quite precisely, and the block is basically a square tube, meaning hollow.

 

[The Chairman]

I use the student (free) version of OnShape to produce STL files. Reverse engineering is pretty easy, but I create a lot of things from scratch. Never having done CAD before, I sat down at my terminal on a Sunday Morning and by that afternoon, I had produced the first version of this:

This is replacement battery holder for a dive light. The blue pieces are TPU which is quite flexible and the marble pieces are PLA which are quite rigid. After you add the requisite hardware, it will hold twelve 18650 batteries in a 4S3P configuration.

 

[The Chairman]

I took the liberty to move this to our 3D printing, laser and CNC forum... I am not an expert in any of those topics, but I do OK.

 

[The Chairman]

The only potential issue I see is accuracy of measurements...

Digital calipers are pretty inexpensive. The mostly metal ones are $20, but they go down to @ $11 for all plastic.

 

[James79]

In no particular order:

As @The Chairman said, a set of digital calipers are your friend.

As to post processing for fitment needed (filing, sanding, etc.) it comes down to accuracy of the design, and calibration of the printer (does a 20mm cube design print as a true 20mm cube). I have my printer dialed in pretty well and am lazy, so I try to design for little or no post processing.

There aren't sprues, but there are layer lines. Again, depending on printer settings they may be more or less pronounced, but they will be there. Whether they matter for the part you need will determine if you want to sand them out or not. The other issue with layer lines is that they are usually the weakest axis of the print (you typically want them parallel to any bending force, not perpendicular).

For simple shapes like that, TinkerCad will do just fine. I started with TinkerCad and moved on to FreeCad when I moved past the practical capabilities of TinkerCad. There are lots of free to use or just plain free CAD programs, and YouTube tutorials are you friend!

Lastly, as small as those parts look, shoot me a DM and I could probably print them for you just for giggles (provided you don't live somewhere that would make shipping prohibitive). Not knowing the use case for them, I'd probably default to ABS for rigid parts or TPU if they need flex.

Respectfully,

James

 

[sprockjohnson]

What amount of precision is necessary? I've designed numerous items in Tinkercad and found that one variable regarding the amount of precision you will get is the material itself. Some materials, such as PETG, have various degrees of thermal expansion/ contraction and depending on the tolerances you need this can wreck havoc with those. If it is just to use for lost wax casting then expect to do some post-production sanding/ finishing and just use something simple like PLA. If just for printing then expect some trial and error and multiple prints in whatever material you need for strength and/ or water tolerance.