silicone tube cutting guide - 000 (failed)
Cutting a straight edge into flexible tubing with only hand tools is not a super easy task. The goal of this cutting guide is to provide an easy to use and low-tech solution to cutting flexible tubing for combat robot wheels.
A cylinder with slots in it should be able to hold the tubing and provide a guide for a knife blade to rest. The idea is the tube would be placed over the cylinder, a utility knife blade would be pressed into the slot, then the entire guide and tube would be rolled along a table to create a cut around the perimeter of the tube.
cad design
A few minutes of Fusion 360 work and the following is born. The slots are 1mm tall with a .5mm chamfer on each side so that it comes to a point in the middle for the blade to rest. Each segment is 10mm to the center of the slot; this corresponds with the 10mm rings I need for wheels I am producing. This cutting guide will allow for 4 ring segments to be cut before having to reposition the tubing.
production of the prototype
The prototype cutting guide will be printed out of TPU. I find TPU to be decent choice for tools and guides since it is fairly tough and can hold up to a good amount of abuse without critically failing.
print settings
- 5 top layers
- 5 bottom layers
- 4 perimeter layers
- 23% rectilinear infill
- no supports or brims
Total print time comes out to 1h37m with 24.52 grams of filament used for a total cost of $0.74.
results
The print came out great, but ultimately the cutting guide was not very good. I was able to make cuts that were straighter, so at least some progress was made, but this prototype failed to meet most of the design goals.
issues
- Grooves are too small to be noticeable through the tubing
- The tube stretches and skews when put on the guide, making it near impossible to get a straight cut
- The grooves are too small to retain the knife blade while cutting
