Compact belt tensioner for 20x20 aluminum profiles (Tronxy, Ender...)

thingiverse

This design is suitable for most machines that use belts and 20x20 aluminum extrusions, like the surprisingly good and exceedingly cheap Tronxy X1 printer. I was inspired by fessyfoos' design and others. However it was redesigned from scratch in Openscad in order to make it significantly smaller, faster and easier to print (e.g. no curved overhang, simpler shapes). Also, this design works as well on X and on Y axis: it will not get in the way of moving bed as it is barely bigger than the footprint of the alu profile itself. You can tune the threaded length in the source code, but I think that the current adjustable range should be OK for most (you could shorten the end of the belt on some printers). Tell me if ever you need a bigger range, which would make the object longer as well. There are TWO variants. I recommend the 2.5mm variants that offset the belt inwards (just spot the file name). They avoid the risk to rub the belt teeth either on the edges of the aluminum profile (as the standard belt tensioners), or against the carrier's wheels (if you have some). Note that the openscad source code is published on https://github.com/MoonCactus/3dp_compact_belt_tensioner