Designed with the challenge of working in brittle PLA! Use one for a bracelet, combine for even more size options!

This is something I challenged myself to make in a way that would work with simple PLA. Experimenting with HueForge and seeing such amazingly detailed prints that were at the same time so thin and flexible gave me the idea of trying to make something wearable like this This was also partially inspired by @cyanidesugar's bracelets!

I wanted to be able to have it in whatever color/size I might need. I like the simple look of the spiky “punk” bracelets/chokers. I wanted to replicate this simple look in a way that could be extremely versatile. After something like 10 prototypes, I'd say it was a success!

This uses a very simple mechanism borrowed from the one you see often on baseball caps. 2 pegs snap into place in corresponding holes to determine the sizing. The holes are spaced by 1cm, and you get 7 possible sizes for a single band on its own (a 6cm size range). You can also snap multiple bands into each other for more possibilities! See specific size info listed below.

This could be easily have been achieved in TPU, or likely even PETG for that matter, but all my testing was done in PLA, so that I could design around the most commonly used/available 3D printing material.

Currently, you can use the following configurations:

• 1 band for a diameter range of 17.5cm-23.5cm.
• 2 bands for a diameter range of 35cm-45cm.
• 3 bands for a diameter range of 55cm-70cm.
• 4 bands for a diameter range of 70cm-95cm (this is where the ranges start to overlap, and it's best to use more bands at a smaller setting, rather than fewer bands at a larger setting for a more consistent spike spacing…. so for a diameter of exactly 70cm, I recommend using 4 bands instead of 3).
• With 5+ bands, “infinitely” larger sizes!

There are also loops of 2 different widths included to help keep the band from flopping around on certain size settings. Feel free to scale the width to whatever works for you too! These can also serve to attach additional accessories to your band! They look like this (all printed in one size here):

Important Printing Info!

Other than the model itself, I had to play around a lot with the printing settings to find what worked well. Here are some notes you should review before printing:

• Small differences can make this too thick, or too thin. You want it to be strong, but with a brittle material like PLA, not too rigid or else it will not bend and will easily crease/crack. The line direction also matters a lot for durability as well as aesthetics. I found great success printing with 0.16mm layer height (including the first layer), having the band only consist of 3 layers. The bottom and top layer of the band should have the infill angle set such that the lines are “with the grain” of the band, or parallel/in line with it lengthwise. This keeps the top surface looking nice, and makes the band less likely to crack between layer lines when it's bent as it's meant to be.
• When I tried printing the spikes with silk PLA (but not the band), they had a tendency to pop off when handled. I don't recommend combining different types of material in this way. When I did multicolor successfully, the different colors were both the same type of filament, with the only difference being the color option. In my case, the prints you see in the photos are all done with Bambu PLA Basic colors.
• I think that ironing applied to the visible portions of the band make it look great, but if you choose to use it, make sure it isn't applying ironing to any of the holes or other hidden parts, as it will affect fitment and possibly prevent it from working altogether. You can use a modifier in your slicer to define what parts get ironed. Also, don't iron the band at all when printing the “with perfs” version. The ironing will fuse the perforations together, negating their whole purpose, and possibly rendering it unusable.
• Keep in mind that all materials (even within PLA variants) have different properties, and some trial and error may be necessary for your particular material.

Safety Disclaimer

As with any 3D printing, there is a possibility of sharp points, etc. Especially if you or someone else will be wearing this in some way, please take caution to make absolutely sure that there aren't any printing issues that may cause injury. Make sure to test the fitment before wearing, and make sure that it's not too tight, and that it can easily be removed if necessary. Also give it a durability test, as you don't want any issues with normal use that may compromise the item in an unsafe or inconvenient way. And please be aware that pieces can be broken off and pose a choking hazard, etc. These aren't children's toys, and should always be handled by an adult. Most of this is just common sense, but please take extra care with how you handle/use this model given what it is!

Possible future plans:

If/when I may revisit this project (no promises), the additions I'd likely make first are the following:

• Some additional versions that are more ideal for larger/smaller sizing. The goal here was “one size fits most”, and as such some sizes aren't possible (namely the smallest sizes, and in-between sizes for multiple bands). Also, the largest sizes don't always look quite right due to there being a significant gap between 2 of the spikes.
• Some aesthetic variations that may feature different spike types, band widths, or new features altogether!
• Some trinkets that can be used to accessorize this accessory.

So stay tuned! If there is interest shown that will likely affect things. If anything is made it may be updated to this model listing, or a new one(s) altogether depending.

Enjoy!