Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: nava on January 13, 2012, 07:19:04 AM
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So in preparing the z height for the my tools 0 starting point with the mach3 internal mpg I'm having some strange issues I cant figure out.
Steps to reproduce
1. I jog down to set the Z height using the internal mach3 mpg while at the same time measuring with a dial gauge(used 2 different ones at the same time)
2. Both dials read 0 and then I set z to 0(OK should now be zero)
3. Pressing goto 0 should now return the dial gauges to 0 but instead the dials move .03mm past 0.
4. Pressing goto 0 again returns the dials to 0.03mm
I can repeat step 4 over and over again and the dials always return to the same .03 position. I have inputeed my backlash a few months ago(.07mm) and because the dials return to the same .03 past z 0 positron I think the backlash calculated correctly.
I also tried jogging the tool down past the dials 0 then jogging it back up to 0 before i set the soft zero on the z. If I'm jogging up to z then when i hit goto 0 the tool is .01mm below 0.
I cant really understand whats going on here but obviously it isn't that great for setting up my tool positions.
Any insight to what may be going on would be wonderful.
I also have the same error when using my xbox controller as my mpg:( And if it helps I still have it plugged in while using the mach3 internal mpg
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Try with backlash disabled.
What are your steps per unit on Z?
Hood
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My Z is 400 steps per mm.
Ill try with the backlash disabled..itching to finish work now and get back to the shop:)
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Ok thats fine, was just wondering if you were really course on the Z but thats not the case.
Hood
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Im just thinking more about it and I guess I cant get my head around why the goto 0 works after the first set..reaptedly goes back to where it thinks z is. I must have pressed goto 0 about 30 times and its returning to the same position on the dial everytime. My thought is that perhaps the backlash is calculated a little differnt for the mpg. Anyway Ill try to disable the backlash when im there in 2 hours or so.
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Ok so had time to test with backlash diabled (allways restarted mach before retesting also tried restarting my control box). Changing the backlash had no effect at all apart froom i can her the %50 speed kick but goto 0 returns to 0 on my dial..which is odd. I even tried testing if backlash comp was working at all by setting it to 5mm and again I can hear the motors speed change but still returns to 0 the dial. I played with my jog speed in the mpg and when slow jog is on anything else than 100% I get little errors +- .01mm...if I leave it on 100% to set the Z it returns to the dail spot on..its strange for me because I remember setting the backlash comp up parts come out within spec. But now Im even more unsure that Ill be able to reset backlash again.
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Not sure what you are saying, its working correctly now or not?
Can you attach your xml please and I will have a look at the settings and see if I can find an issue.
Hood
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its not working correctly as backlash doesnt seem to come into effect so I cant really test it. The machine returns to 0 even though it should evershoot with backlash set to 5mm..and if BLC is off the dail and th dro also return to 0.
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Not sure what is going on then.
I do see you have the A of MPG set to same port and pins as Z Limit/Home and the B is set to the same port and pin as the E-Stop. Thats not correct and may cause you issues.
Do you have a MPG connected?
Hood
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I have an xbox conroller with the plugin but no other mpg. I'm also not sure how those other setting are wrong as the XML was given to me by the company that made the Cnc conversion..what should I do to the settings to change it? Thanks for your help:)
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Well if you have a MPG on the xbox I dont think you will need the MPG set up in Ports and Pins, Encoders page. Could be wrong but just disable it and see if al is still fine.
Hood
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Ok so I changed the setting and now I can see backlash working correctly but the other behaviour is still the same. So then I started to think its a condition of velocity and or mechanical. So I looked closer at the dial while Im jogging in .01 single step mode. What I did was to move in .01 increments for a total of.1mm and low and behold the dial only moves .06mm that's why when I press goto the dial seems to move beyond the original value set on my dial gauge. The goto 0 is moving allot faster up and down and this engages the gear drive fully while my small incremental changes don't(at least thats what I think). Doing such movement on my x or y is fine, I can see the dial gauge move properly and setting soft 0 returns it to 0 the first time.
So now I guess I have to look at the mechanical aspects of my z and I'm a little disappointed that my machine is being a bit tricky, has any one had such behavior before mechanically? The machines motors are operated by steppers and a 2:1 belt driveand has ball screws all all 3 axis. I'm not sure the best place to start. I keep it well lubed and clean haven't had any crashes and only cut 2007 alu with it so I be surprised if bearings have allot of wear, but I'm still pretty new at this all.
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What is the m650 macro you have running doing?
Hood
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Not sure hood
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can you attach it and maybe I can figure it out.
Hood
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I had a look in my mach3 folders and couldnt find the g650 macro, I can see it refered to in the XML but Im guessing who ever wrote it didnt include it.
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Its m650 and will, or should, be in the macro folder of the profile you are using and will be called m650.m1s
Hood
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Sorry hood putting g650 was just a typo..I had looked for the m650.m1s and its not there
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Ok well maybe best to delete it from the init string if its not being used. Probably wont do any harm but its just another thing for Mach to look for and if its not there its just wasting resources. On the grand scale of things it would likely be a very tiny amount but still if its not needed then dont waste is my philosophy .
Hood
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Hood thanks very much in helping work through my machine errors. Since I was able to eliminate any soft errors I focused the rest of the day to mechanical and in the end a pull down of the Z and reassembly with fresh lube and re tightening of the belt fixed my problem within about .005mm which I'm able to live with. Now to cut some stuff again yay! ;D
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0.005mm is excellent :)
Hood