I owned Thule backpack for almost 10 years or so. It is by far my favorite and durable one. After some time my zippers started to break which is shame, because I absolutely love how they feel and look.

I could not find them anywhere so I purchased small roll of TPU and got designing.

DESIGN

It is heavily inspired as you can see, just optimized for 3D printing. Originally I wanted to utilize the metal part for durability, however it is not ideal and was worried about how well it would hold with overprinting so I designed it from scratch.

For the inside part I would recommend to use ASA if you plan to wear it a lot (due to UV), however I did not have the roll and went for PETG, PLA should be fine as well. In case they fail, I might tweak the design a bit or print it from other material.

The flexible outside I printed from TPU so have the same feeling as original and I have to say it is very close.

PRINTING

1. Print the first plate from ASA, PETG or PLA
2. If the top surface is not perfect due to material tuning, just sand it a bit so it is flat and smooth
3. Print the second plate from TPU
4. Print will pause automatically
5. Insert the inside part into it and hit continue
6. That's it, part should come out real great and you can install it on your backpack