Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: WMT on January 04, 2013, 11:51:08 PM
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Has anyone had trouble with their rotary axis going the long way around in G1 mode?
If I feed G1 A10 F100 from Zero. It Feeds
If I G1 A9 from A10 it goes the long way around instead of moving 1 degree.
I have the rollover box ticked in general config andthe other one that makes the G0 take the shortest route.
Current Version of Mach3 is 3.043.062
Any suggestions would be greatly appreciated
Cheers ???
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Uncheck the Rot 360 rollover. I think a bug creeped in.
(;-) TP
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I did that and it now works correctly for G1.
Thank you.
But why have the ability to go above 360 degrees?
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G1 A-9 F100 will move it back when rollover is chosen.
Hood
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Hi Hood. Yes that works. But my post processor wont add the - "minus" if there is a direction change. And its too hard to go through 7500 blocks of G code to figure out which ones to add a minus too.
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Either you will have to adjust the PP to do so or just disable the rollover.
It has been that way as long as I can recall.
Hood
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Thanks Hood. Do you know why there is a need to count more than 360 degrees?
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One situation may be if you were wishing to use the A axis for a spindle so you could have rigid tapping (assuming its a servo or stepper spindle)then you would likely not want the roll over.
Hood
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That makes plenty of sense. If any one wants to check it out. Ive put a short clip on Youtube https://www.youtube.com/watch?v=MckXFOyQBtw&feature=player_detailpage#t=2s
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Looks very nice, do you have a build thread for it?
Hood
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Thanks Hood. No I dont have a build thread for it. But I do have a sub page on my website. http://www.intaglio.co.nz/hm463.html
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Do you know why there is a need to count more than 360 degrees?
Don't have a specific answer for you but i have used it on the lathe to cut a continous line around a cylinder such that
the A rotates 2 revolutions at some z distance and thus you have a barber pole effect.
Sort of like slaving a rotary to an axis. Haven't fooled with that in a long time.
RICH
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Looks good :)
Do you need the brake with that reduction?
Got any pics of the motor?
Hood
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Mate - That does look good - well done, Do you have any more construction details and photos?
Steve
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Hi Rich :). I would have to say that I havent had the need to slave an axis yet. Perehaps in the future I might need to do it.
It sort of looks like I dont need a brake Hood. But I bet if I didnt put one on it. I would need it. Especially when machining large steel things.
I will throw a pic of the motor fitted on my web page for you.
Thanks Steve. Ive got a few more pics on my website. And Ive got a 3D CAD model of it.
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Thanks for that, was kind of interested in the gearbox,do you have a link?
Hood
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Its three pics up from the bottom of the page Hood http://www.intaglio.co.nz/hm463.html
Gearbox is a CSF-100-25 Harmonic Drive. They are very compact with zero backlash. Mind due anything looks compact next to the 660 watt servo.
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Ah sorry, didnt make myself too clear. Was wondering if you had a link to where you got the box. But now I know the model I can google it :) Thanks
Hood
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Hi WHT
I have the servo and a harmonic drive - it looks about the same as yours, mine is 100 to 1 and about 5 1/4 inches in outside diameter. Its a Harmonic Drive Technologies HDC 2M 100 2A. I was planning to mimic my lathe spindle with a D1 4 chuck mount so I could use the same chucks as well as the collets that go in it (5C). I have been thinking about how to get it all together for a few months now. You have given me some inspiration with yours.
Is your belt drive 1 to 1 or something else - I was planning on 1 to 1 with my servo's encoder having 10,000 positions I didn't think I would need more resolution and at 3000 rpm at the servo I could still get 30 rpm at the chuck which should be heaps.
Please tell me more about your brake - like what cylinder did you use - a commercial one? and where you got it. Does it automatically apply when the spindle has stopped?
The CAD drawings would be good to look at - if you wanted to post them here - others might get some use from them as well.
I take it from your web site your a Kiwi - Bad luck about the Cricket - bloody South Africans smacked us too in Oz.
Steve
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Hi Steve. I'm glad you got some ideas from it. There is a slight reduction in the belts too. About a third. But with what Ive found so far is its not really needed with the 100 to 1 from the harmonic drive. As for the brake. I havent got around to making it yet. It uses a SMC pneumatics CQ2A50-10DC air cylinder mounted to a custom floating caliper that I designed. It automatically clamps and unclamps from a signal in the Granite Devices servo drive. I will throw some more pics on my website later in the week of the braking system.
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The attachment is a pic of two helix's I machined yesterday. Left one is G1 X-50 A359. The right one is X-50 A1800. So I guess from this little test it answers my question.
Thanks for everyones input.