Hi all, this might be a little out there so bear with me. Maybe this is just a problem with my mini or maybe it really is a widespread design flaw which i sort of suspect (not that i am knocking the original design team necessarily).
So here is the issue that has bugged me for quite some time and i have not seen anyone talk about it. It is the size mismatch on the mini between the very small 16 tooth GT2 pulley for the belt and the very large (in comparison) standard skate bearing on the other side therefore creating a triangle. I have run into the issue of trying to tighten my belt and sometimes have gotten it too tight so it wont go all the way across and too loose when it gets close to the motor. So basically too problems at once. I have had it okay for awhile but my belts are loose now and not making true circles anymore and thus i am nearing having to battle this issue again soon.
My main question is: Why are not the pulley and bearings the same size for even tension? On the surface this seems to just be a case of crappy engineering. But i also see that 20 tooth gears are common on other reprap style 3d printers and i have to wonder if the prototype the mini came out of originally used 20 tooth pulleys which probably would have been closer to the standard skate bearing size and probably would have had less of this issue.
To possible fixes come to mind.
- increase the size of lulzbot mini pulleys to 20teeth and increase print speed but loose resolution AND update the marlin firmware to match. (of which i could probably do myself but it sortof seems like a problem with ALL lulzbot minis maybe).
- Decrease the size of the bearing at the other end. But would require some sort of adapter or redisgn of the shaft in the far right x-axis piece. Perhaps for something like this https://www.amazon.com/BIQU-16Teeth-Aluminum-Timing-Printer/dp/B07CFX5RDK.
A separate issue is the belt tighteners themselves. I find it extremely difficult to get to the screws with a standard L shaped Allen wrench. Is it possible to come up with a better easier to access belt tightening system
I don’t know. Am i just crazy? Do these issues only affect me? Since no one is talking about these i sort of feel like i am alone here floating out on the ocean.