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Post by riton39 on Dec 11, 2016 12:19:19 GMT
It becomes really incomprehensible ... It's not easy, everything looks good
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gokhan
Junior Member
Posts: 89
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Post by gokhan on Dec 14, 2016 13:13:05 GMT
Finally, new shafts with special keyway and special keys arrived. I installed two of them and the backlash is more or less unrecognizible. I will install the rest later since they require new encoder holders. My 3d printer is currently printing two of them a day Here are some photos.
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gokhan
Junior Member
Posts: 89
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Post by gokhan on Dec 18, 2016 19:04:52 GMT
I finally completed the replacement of the reductor shafts. Also with the implementation of springs, it looks working quite good. I don't sense any vibration or oscillation at all unless if it wasn't intended. I still want to test with some sharp maneuvres but i believe this round is over. Thanks for your valuable comments and support. Here is the final video. www.youtube.com/watch?v=EFYtUHsYpBE
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Post by clyevo on Feb 2, 2017 10:52:27 GMT
i only realized what you meant by backlash is the teeth of the helical gears and the worm shaft gears tolerances are to huge. I think i have the same problem with my new motions simulator. Previously i have used nmrv size 90 (2 degree backlash) now this new nmrv size 75 has more prominent backlash (5 degree). Since the 1.8 degrees of lever rotation equals to 1% of sensor displacement in thanos board this causes more problem. Not to mention instability of the platform. It wobbles. Since my design is servo inside and lever facing inside. It might be more of a problem since minute movement of the lever cause huge displacement of the platform. So i ll try new design with servo inside and lever facing outside when i have the free time. Hope this will reduce the wobble. Edit: and i might reduce the lever from 20cm to 15cm. Is the angle of backlash available in most chinese manufacturer specification? If so, i would probably ask the manufacturer to provide me with this. Can you guys tell me your experience in backlash. I would like to know if 5 degree backlash is normal?? Finally, new shafts with special keyway and special keys arrived. I installed two of them and the backlash is more or less unrecognizible. I will install the rest later since they require new encoder holders. My 3d printer is currently printing two of them a day Here are some photos. This shaft key is design to make your lever fit more tightly in the shaft? Before this, the lever and the shaft does fit well enough? Does this fix your backlash problem or was it purely your gearbox problem?
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gokhan
Junior Member
Posts: 89
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Post by gokhan on Feb 2, 2017 16:26:30 GMT
I don' t have any experience with chinese suppliers. The suppliers here in Turkey has 2 options with regard to backlash. Regular types(1-2 degrees at max) and low backlash types(<0.5 degrees). They say the backlash is needed for lowering the friction and having long product life. If your application is something like driving a conveyor belt for potatos, regular type is perfect. But if your conveyor belt is carrying glass articles or it is a 6dof platform which is our case then you should go for low backlash type. Low backlash is manufactured upon order so no stock at all. I had to order and wait 3 weeks to get them. I use 90 size and probably have a backlash of less than 1 degrees. I am quite happy with them. one of the older ones(regular type) had 7 degrees of backlash. So I had to change them. But please keep in mind the backlash you are experiencing is the sum of your drive chain. It also comes from joint, fixture and even encoder connections. I think total backlash shouldn't be more than 1 degree. i only realized what you meant by backlash is the teeth of the helical gears and the worm shaft gears tolerances are to huge. I think i have the same problem with my new motions simulator. Previously i have used nmrv size 90 (2 degree backlash) now this new nmrv size 75 has more prominent backlash (5 degree). Since the 1.8 degrees of lever rotation equals to 1% of sensor displacement in thanos board this causes more problem. Not to mention instability of the platform. It wobbles. Since my design is servo inside and lever facing inside. It might be more of a problem since minute movement of the lever cause huge displacement of the platform. So i ll try new design with servo inside and lever facing outside when i have the free time. Hope this will reduce the wobble. Edit: and i might reduce the lever from 20cm to 15cm. Is the angle of backlash available in most chinese manufacturer specification? If so, i would probably ask the manufacturer to provide me with this. Can you guys tell me your experience in backlash. I would like to know if 5 degree backlash is normal?? Finally, new shafts with special keyway and special keys arrived. I installed two of them and the backlash is more or less unrecognizible. I will install the rest later since they require new encoder holders. My 3d printer is currently printing two of them a day Here are some photos. This shaft key is design to make your lever fit more tightly in the shaft? Before this, the lever and the shaft does fit well enough? Does this fix your backlash problem or was it purely your gearbox problem?
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