Heat Forming and Making 3D Printed Wristband

I came up with this project because although there are a lot of 3d printed bracelets available for download, most of them take a long time to print and anything fancy or complicated requires a bajillion supports at super fine detail. I also teach 3D Printing to kids and this project is simple enough to follow yet piques their interest enough to trick them into learning things. This is a quick and easy modeling and 3D printing job, the key is to print thin and flat, change filament midprint for contrast, then heat form with hot water.

Tools and Materials Used:

• 3D Printer + PLA filament (I haven't tried this technique with ABS, please let me know how it turns out if you do) I used Makerbot Replicator2 and Prusa i3 MKII.
• 3D Modeling software. I used Tinkercad
• Kitchen Sink with hot water
• ruler
• Optional: something round as your wrist form. I used a glass bottle

• Wrap a strip of paper around your wrist, make a mark by folding.
• Unfold then measure the strip of paper. Mine is roughly 157 millimeters.

This is how the voronoi bracelet is made in tinkercad, a free and easy-to-use 3D CAD web app made specifically with 3D printing in mind. You do need an email to sign up for an account to use it.

3D Modeling the Bracelet:

• start with a box
  • 2 millimeters tall
  • 25 millimeters wide (could be wider or skinnier, up to you)
  • length of your wrist. My wrist measured 157mm and I used 150mm at first but it was a little too short, so I made another one with 160mm which was perfect. so simply use your wrist measurement.
• Make a voronoi hole pattern to combine with your solid box. This generates the solid voronoi pattern.
• Add a 1mm tall solid backing to your voronoi pattern to give it structural integrity and heft.
• Fillet the edges.

Instead of the voronoi pattern feel free to simply use letters or other patterns. The steps are the same - 2mm tall pattern, 1mm tall backing.

For more specific instructions see annotated screen caps. I've also included the resulting STL for download if you want to skip this step. Keep in mind that it is 160mm in length, so scale as needed for your own wrist. Or simply duplicate then edit in tinkercad: https://www.tinkercad.com/things/ctaNZp9HX37

I've also included an stl file for a #watertribe bracelet. It is much thinner at 1mm tall total. I find that anywhere between 1mm and 2mm thick works pretty well for this process.

In order to make the contrasting bicolor print, a filament change is made after the backing is printed.

PrusaPrinters.org makes this free and handy app called colorprint which goes through your GCode and inserts a filament change routine at your desired height. It automatically pauses the print then beeps so you know to change the filament.

I also used Makerbot Rep2's built-in "Pause at Z height" feature to change the filament.

If you feel confident and/or lazy you can simply clip off the filament mid print without pause and insert new filament.

Using a round form is optional, I find that it really helps with making a nice and round smooth curve.

Place the wristband under hot running water, I used the hottest setting in a home sink.

Let the water run for a few seconds, then quickly remove it and bend around the round form or your wrist.

My water was hot enough that I wouldn't put my hand under it for a prolonged period of time, but not hot enough to burn me if I did. Use common sense.

Make sure to only bend and make round a little bit at a time. I did it too quickly at first and the harsh bend was very noticeable.

That's it! If you feel industrious try using a heat gun on an actual wrist form for jewelry-making.