coupler for AC servo
I'm doing a cnc conversion on a 13x40 gearhead lathe.
My Z servo will be belt driven, so I think I can handle that. Do any of you have a recommendation for a zero backlash coupling for the X drive, which will be direct? (metric AC servos) LLoyd |
coupler for AC servo
"Lloyd E. Sponenburgh" wrote: I'm doing a cnc conversion on a 13x40 gearhead lathe. My Z servo will be belt driven, so I think I can handle that. Do any of you have a recommendation for a zero backlash coupling for the X drive, which will be direct? (metric AC servos) LLoyd That depends on how accurately you can mount the servo. The big CNC machines I used to work on had rigid couplings with precisely located motors. For a retrofit you are probably looking at a coupling that will accommodate some misalignment. I'd look at the helical couplings or the flex disk couplings. I wouldn't even consider anything like the lovejoy or similar with any sort of insert. Try Mcmaster.com, flexible shaft couplings, catalog page 1165. |
coupler for AC servo
On Tue, 16 Aug 2011 07:36:23 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote: I'm doing a cnc conversion on a 13x40 gearhead lathe. My Z servo will be belt driven, so I think I can handle that. Do any of you have a recommendation for a zero backlash coupling for the X drive, which will be direct? (metric AC servos) LLoyd I like Oldham couplings for this sort of thing. They're much cheaper than higher performance options like bellows couplings, less fragile and cheaper than helical beam couplings, and usually good enough in all but the most demanding motion control apps. McMaster has a limited selection; Lovejoy and Huco have much more. Lovejoy has some comparison info in their catalog. http://www.lovejoy-inc.com/products/...couplings.aspx -- Ned Simmons |
coupler for AC servo
On Tue, 16 Aug 2011 09:32:29 -0500, "Pete C."
wrote: "Lloyd E. Sponenburgh" wrote: I'm doing a cnc conversion on a 13x40 gearhead lathe. My Z servo will be belt driven, so I think I can handle that. Do any of you have a recommendation for a zero backlash coupling for the X drive, which will be direct? (metric AC servos) LLoyd That depends on how accurately you can mount the servo. The big CNC machines I used to work on had rigid couplings with precisely located motors. For a retrofit you are probably looking at a coupling that will accommodate some misalignment. I'd look at the helical couplings or the flex disk couplings. I wouldn't even consider anything like the lovejoy or similar with any sort of insert. Try Mcmaster.com, flexible shaft couplings, catalog page 1165. Hmm. I like the lovejoy for retrofits. Easy to disassemble. The only possible solution on a couple locationsI've had. I suppose a purist would say there's an RCH of backlash in them. IMHO, a tinsy fraction of the total system backlash. I suppose if your building parts for NASA or Medtronic it might not be good enough. Just my 2 cents Karl |
coupler for AC servo
Ned Simmons wrote: On Tue, 16 Aug 2011 07:36:23 -0500, "Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote: I'm doing a cnc conversion on a 13x40 gearhead lathe. My Z servo will be belt driven, so I think I can handle that. Do any of you have a recommendation for a zero backlash coupling for the X drive, which will be direct? (metric AC servos) LLoyd I like Oldham couplings for this sort of thing. They're much cheaper than higher performance options like bellows couplings, less fragile and cheaper than helical beam couplings, and usually good enough in all but the most demanding motion control apps. McMaster has a limited selection; Lovejoy and Huco have much more. Lovejoy has some comparison info in their catalog. http://www.lovejoy-inc.com/products/...couplings.aspx Those are not zero backlash couplers. McMaster has zero backlash flexible couplers specifically intended for servo use. They aren't particularly cheap, but if you only need one of them they should be acceptable. |
coupler for AC servo
On Tue, 16 Aug 2011 09:32:29 -0500, "Pete C."
wrote: "Lloyd E. Sponenburgh" wrote: I'm doing a cnc conversion on a 13x40 gearhead lathe. My Z servo will be belt driven, so I think I can handle that. Do any of you have a recommendation for a zero backlash coupling for the X drive, which will be direct? (metric AC servos) LLoyd That depends on how accurately you can mount the servo. The big CNC machines I used to work on had rigid couplings with precisely located motors. For a retrofit you are probably looking at a coupling that will accommodate some misalignment. I'd look at the helical couplings or the flex disk couplings. I wouldn't even consider anything like the lovejoy or similar with any sort of insert. Try Mcmaster.com, flexible shaft couplings, catalog page 1165. Helical couplings for sure. One of my clients... good **** Maynard http://www.rocomcorp.com/ Gunner -- "The danger to America is not Barack Obama but a citizenry capable of entrusting a man like him with the Presidency. It will be far easier to limit and undo the follies of an Obama presidency than to restore the necessary common sense and good judgment to a depraved electorate willing to have such a man for their? president.. Blaming the prince of the fools should not blind anyone to the vast confederacy of fools that made him their prince". |
coupler for AC servo
On Tue, 16 Aug 2011 11:21:27 -0500, "Pete C."
wrote: Ned Simmons wrote: On Tue, 16 Aug 2011 07:36:23 -0500, "Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote: I'm doing a cnc conversion on a 13x40 gearhead lathe. My Z servo will be belt driven, so I think I can handle that. Do any of you have a recommendation for a zero backlash coupling for the X drive, which will be direct? (metric AC servos) LLoyd I like Oldham couplings for this sort of thing. They're much cheaper than higher performance options like bellows couplings, less fragile and cheaper than helical beam couplings, and usually good enough in all but the most demanding motion control apps. McMaster has a limited selection; Lovejoy and Huco have much more. Lovejoy has some comparison info in their catalog. http://www.lovejoy-inc.com/products/...couplings.aspx Those are not zero backlash couplers. McMaster has zero backlash flexible couplers specifically intended for servo use. They aren't particularly cheap, but if you only need one of them they should be acceptable. The Oldham couplings from Huco and Lovejoy are zero backlash, as are those that McMaster stocks. There's a light interference fit between the aluminum hubs and the delrin discs. The disc is much stiffer torsionally than the elastomer spider in typical jaw couplings, which also suffer from backlash. Oldhams are stiffer and have lower inertia than a helical beam of similar torque rating. And if you bust one, replacement discs are a couple dollars -- cheap enough to keep a couple spares on hand. In highly dynamic systems a disc or bellows coupling may be necessary, but I've used Oldhams in many less demaninding apps with no problems. -- Ned Simmons |
coupler for AC servo
Ned Simmons wrote: On Tue, 16 Aug 2011 11:21:27 -0500, "Pete C." wrote: Ned Simmons wrote: On Tue, 16 Aug 2011 07:36:23 -0500, "Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote: I'm doing a cnc conversion on a 13x40 gearhead lathe. My Z servo will be belt driven, so I think I can handle that. Do any of you have a recommendation for a zero backlash coupling for the X drive, which will be direct? (metric AC servos) LLoyd I like Oldham couplings for this sort of thing. They're much cheaper than higher performance options like bellows couplings, less fragile and cheaper than helical beam couplings, and usually good enough in all but the most demanding motion control apps. McMaster has a limited selection; Lovejoy and Huco have much more. Lovejoy has some comparison info in their catalog. http://www.lovejoy-inc.com/products/...couplings.aspx Those are not zero backlash couplers. McMaster has zero backlash flexible couplers specifically intended for servo use. They aren't particularly cheap, but if you only need one of them they should be acceptable. The Oldham couplings from Huco and Lovejoy are zero backlash, The link you provided does not indicate the Oldham style is zero backlash. The only three piece coupler on that page indicated as zero backlash is the curved jaw GS series. |
coupler for AC servo
On Tue, 16 Aug 2011 13:02:19 -0500, "Pete C."
wrote: Ned Simmons wrote: On Tue, 16 Aug 2011 11:21:27 -0500, "Pete C." wrote: Ned Simmons wrote: On Tue, 16 Aug 2011 07:36:23 -0500, "Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote: I'm doing a cnc conversion on a 13x40 gearhead lathe. My Z servo will be belt driven, so I think I can handle that. Do any of you have a recommendation for a zero backlash coupling for the X drive, which will be direct? (metric AC servos) LLoyd I like Oldham couplings for this sort of thing. They're much cheaper than higher performance options like bellows couplings, less fragile and cheaper than helical beam couplings, and usually good enough in all but the most demanding motion control apps. McMaster has a limited selection; Lovejoy and Huco have much more. Lovejoy has some comparison info in their catalog. http://www.lovejoy-inc.com/products/...couplings.aspx Those are not zero backlash couplers. McMaster has zero backlash flexible couplers specifically intended for servo use. They aren't particularly cheap, but if you only need one of them they should be acceptable. The Oldham couplings from Huco and Lovejoy are zero backlash, The link you provided does not indicate the Oldham style is zero backlash. The only three piece coupler on that page indicated as zero backlash is the curved jaw GS series. You're right, it doesn't say so specifically, but the page also neglects to specify that the bellows coupling is zero backlash. Here's Huco's description: "Rotation is transmitted through a central disc that slides over the tenons on the hubs under controlled preload conditions to eliminate backlash." http://www.huco.com/products.asp?cat=57 -- Ned Simmons |
coupler for AC servo
On Tue, 16 Aug 2011 14:17:31 -0400, Ned Simmons wrote:
The link you provided does not indicate the Oldham style is zero backlash. The only three piece coupler on that page indicated as zero backlash is the curved jaw GS series. You're right, it doesn't say so specifically, but the page also neglects to specify that the bellows coupling is zero backlash. Here's Huco's description: "Rotation is transmitted through a central disc that slides over the tenons on the hubs under controlled preload conditions to eliminate backlash." http://www.huco.com/products.asp?cat=57 -- Ned Simmons This is what you need http://www.huco.com/products.asp?cat=104 Rocom provides them as well. -- "The danger to America is not Barack Obama but a citizenry capable of entrusting a man like him with the Presidency. It will be far easier to limit and undo the follies of an Obama presidency than to restore the necessary common sense and good judgment to a depraved electorate willing to have such a man for their? president.. Blaming the prince of the fools should not blind anyone to the vast confederacy of fools that made him their prince". |
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