Attachment 2301
Its work in progress but you get the idea
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Attachment 2301
Its work in progress but you get the idea
Stretch in the belt should not actually affect accuracy, so long as you pre-tension it beyond the expected load.
Just my .02p
That's nice to hear. I was originally planning to use bicycle chains and sprockets but I've read quite a few posts here and at the zone that are against them. Ok, back to the drawing board! Thannks for the replies to my queries. I still have a hundred more.Quote:
Stretch in the belt should not actually affect accuracy, so long as you pre-tension it beyond the expected load.
Jordan
@8iggles
That's a clever solution you got there. That's what I should do also.
[IMG]http://i49.photobucket.com/albums/f2.../CNC/Likod.jpg[/IMG]
http://i49.photobucket.com/albums/f2...p/CNC/Baba.jpg
Here's a few picture of my design. I just hope it will work.
Jordan
Nice design - and no reason why it shouldnt work. One criticism if I may; the Z-configuration of the Y-motion belt will be problematic. its inducing a rotational moment on the z-axis which loads the bearings on the high side more than those on the low side. This will wear the bearings unevenly and could result in cantilever stiction. I would redesign that to put in another jockey pulley and make the y-motion belt flat along its length .
Strange I was thinking of the same thing while driving on the way to the grocery just 3 hours ago. I could arrange the jockey pulley such that the belt's ends will be located lower. That would also eliminate the need of different sizes of gantry uprights! And it would look much better too.
Thanks for the helpful suggestion. I hope you'll find more to correct :)
http://i49.photobucket.com/albums/f2...NC/newbelt.jpg
Here's the pulley placement redesign as suggested by irving2008. The belt barely cleared the bottom V bearings. It now looked simplier despite the addition of another set of bearing pulley. Thanks a lot for your help.
jordan
That looks better; the belt tension will pull the tops of the uprights in so depending on the tension and the thickness of the uprights you may need to consider a compression member above or at the belt line. this could simply be a section of tubing, so I'd leave it until you've built it and see if there is measurable deflection.
Nice design, one small thing, add a support bearing at the side of the large pulley on the X axis cross shaft to prevent the shaft from whipping and also to keep tension without it bending the shaft.
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