 Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me. |
Forum Index : Other Stuff : Chain drive for another DIY router table.
| Author | Message | ||||
| KiwiJohn Guru  Joined: 01/12/2005 Location: New ZealandPosts: 691 |
HI, I am starting a DIY router table. I have the steppers and all electronics and power supply, they are now screwed to a board and the software installed on a Linux PC. I am learning about the behaviour of the steppers!  Also going through my stack of 'unknown' steppers collected over the years and finding which ones might be usable.
It might be a total waste of money but I have also bought two 3 phase stepper drivers to, maybe, use with F&P motors. Meanwhile I have acquired some warehouse rack frames, welded steel and I assume factory made and welded in a jig so hopefully square and otherwise true, certainly better than if I was building them myself. The frames are what will set the table size to be 2000mm x about 950. Of course I have a head full of mostly crazy ideas on how to avoid spending too much money on this project! One of the notions is a chain drive for the X axis.. I trust this provides food for thought! 
This is a concept for moving a long axis. The principle is a development of the endless chain hoist. The drive element is on the right and consists of two sprockets/drums/etc that are on the same axis and locked together, they are of close but not identical diameter, all other sprockets/pulleys etc are free running. The gantry moves at a rate that is half the difference between the 'fast' and 'slow' chain/belt/cable speed. Consider for example the case where the drives are 21 and 22 tooth sprockets and a chain of half inch pitch is used, for each revolution of the drive the gantry would move 0.25" Daft or what? Hi Vasi, did you have success with your project ?http://www.thebackshed.com/forum/forum_posts.asp?TID=3249&K W=cnc+router&PN=0&TPN=1 |
||||
Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
I think its a good idea John. Took me a while to get my head around it. I guess you'll have to build a prototype and see how it goes. Only concern is with so much chain there may be too much backlash. You can usually tell the CNC software to allow for a certain level of backlash. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
||||
| KiwiJohn Guru Joined: 01/12/2005 Location: New ZealandPosts: 691 |
Hi Glen Thanks for the comments.. I really dont know if it is workable or not and as you say a prototype is required, how are you with a MIG welder? I have a stack of rack frames ready to be stuck together!
My main fear is that the assembly will have too much friction especially as I presume the chain will need to be very tight. One advantage I see is that the endless chain principle allows the use of large sprockets and I have a feeling that the more teeth engaged with the chain the less backlash there would be. Secondly, the mechanical reduction means there is less need for other gearing and maybe direct drive from a stepper will be possible, gearing of course is also a potential for backlash. The steppers I have are 1.8Nm which dont look very big, I have one bigger one that I dont know the specs of and of course a small pile of F&P motors. John |
||||
Prime_8 Regular Member  Joined: 07/12/2014 Location: CanadaPosts: 51 |
looks very cool. makes me think of the crossed over "H" belt drive for x and y using 1 long belt . ( i forget the name Core-XY i think ) where the gantry would move on 2 axis. ~( yeah was COreXY http://joshuavasquez.com/docs/jVasquez/Projects/coreXY.html ) i wonder if that would work for the cord drive i was planning form my PCB printer. i could snag some extra turns per mm out of the rig that way . Old coder, and bodger of things that may spark. |
||||
 Print this page |
