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Do you have the part number for the belts on SDP-SI? I searched this board using Google like you taught me and could not find the part number. SDP-SI.com is the worlds worst web site for finding something if you don't have themhackney wrote:I've been using timing belts on CNC equipment and printers for awhile. I get my belts at sdp-si.com and they have a great reference library. Belt Tensioning is item #8. The MAX has GT2 2mm belts 6mm wide. You can get the details on pages 51 and 52. These are registration drive belts for positioning (bottom of page 51). That means you do want them on the tighter side to minimize backlash. Even the experts say "Tension values for these applications should bedetermined experimentally to confirm that desired performance characteristics have been achieved." But here is some guidance using this information:
Since the belt is confined in the extrusion slot, you won't be able to do a traditional deflection test by pushing on the belt. So I home the carriages and locate the mid point of the belt. Use something to reach in under the belt and pull it out - I use a big paper clip. Then I pull on the belt. Now, you have to use a little judgement. If you can pull the belt out 1/2" or more using a fair amount of force (roughly 6 pounds), it is too loose. If you can barely move it 1/8" it is way too tight. This is a loooong span so you should expect some deflection.
I was trying to set the Z-height on my MAX last night (just got to that point in the manual) and after setting things in the EEPROM, when I homed again and then brought down to Z0, the head hit the bed. I had to take another .4mm off the height. So my thinking was that perhaps there's too much play in the belts (having never adjusted a belt before I wasn't sure how tight they should be. Searching found this thread. I followed the instruction above and realized that I can *easily* pull out 1/2" and without much force can get to 1 1/2". So obviously my belts are too loosemhackney wrote: Since the belt is confined in the extrusion slot, you won't be able to do a traditional deflection test by pushing on the belt. So I home the carriages and locate the mid point of the belt. Use something to reach in under the belt and pull it out - I use a big paper clip. Then I pull on the belt. Now, you have to use a little judgement. If you can pull the belt out 1/2" or more using a fair amount of force (roughly 6 pounds), it is too loose. If you can barely move it 1/8" it is way too tight. This is a loooong span so you should expect some deflection.
I usually get one belt exactly where I want it, and then I pluck it like a guitar string and just tension the other 2 belts until they play the same notemhackney wrote:If you can pull the belt out 1/2" or more using a fair amount of force (roughly 6 pounds), it is too loose. If you can barely move it 1/8" it is way too tight. This is a loooong span so you should expect some deflection.
