Simple Y tensioner
Simple Y axis tensioner with better access
The standard Y belts clamps are under top printing bed with complicated access. Trying to adjust the tension just to build another tensioner leads to this solution.
All parts that are usually left after build of Mendel Prusa. Straighten the belt to plate loop and increases angle over idler. Easy access for adjustments.
Possible slight loss of Y axis resolution due to movement of tensioner on zip ties. Adds some resitance. May be looks not very pretty.
I think the picture is self-descriptive, but anyway:
- 1 x ~45mm of 8mm screw rod
- 4 x M8 nuts
- 2 x 8mm washers
- 2 x mud washers
- 1 x 802 bearing
- 2 x long nylon zip tie (cable tie)
Screw or put on rod: M8 nut, 2-3mm space, M8 nut, mud washer, 8mm washer, 802 bearing, 8mm washer, mud washer, M8 nut, 2-3mm space, M8 nut. Slightly tight the nuts around bearing. Place on bottom loop of Y belt near idler and tie using zip ties to lower frame screw under the idler. I leave the ends of zip tie free and adjusting the tension as needed.
This is an incredibly simple fix and can work for both the X and Y axis when you have just a small amount of slack in your belts.
Take a piece of masking tape just a few inches long and barely wide enough to cover the bearings themselves and feed it between the bearing and the belt with the adhesive side facing the bearing and slide the axis while feeding the tape onto the surface of the bearing, make sure you do at least one full loop so that it will stay in place.
This will increase the outer diameter of the bearing slightly and help remove any slack that you may have in that axis.
Get the belts as tight as you can before you do this, its no substitute to having your printer setup and adjusted correctly. While its kind of a hack, you can do this for both X and Y and it may help tighten and snug things up if you are experiencing intermittent slippage during your prints.
Don't worry so much about how cleanly or tightly its applied to the bearings since its likely to actually deform and look like a drive pulley after a few minutes of usage.