Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: xaco on March 15, 2010, 12:56:02 PM
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hello everyone, i use mach3 on my small cnc,and it happened to me yesterday that my tool sudenly left toolpath and crashed into material....it was performing a paralel finnish milling along y making a 1x1 inch piece (minus part of a stamping die ) in plexy and going back and forth,bit down and again back forth along y,and in 1 line while taking just a fin layer on the top and coming to "end of stock" he ,insted of turning back like 100 times before,the tool just continued to go straight and after half of inch went deep into material and stoped,"zero" of corse changed to somwhere on that sot where it "landed" .i dont know if zero changed b4 or after.but i didnt notice mistake in g-code cos i took tool out and put it back and this time he did corect his path.. anyone experienced this? Miro
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Sounds like possibly an axis stalled. Did you notice if the toolpath and DROs showed this wrong move?
Hood
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hm,i cant remember what mach toolpath shown but i think taht all the time on toolpath display it was shown toolpath with all lines ,blue 1, and paralel to that green toolpath that tool just passes,but those two were not one on other matching like it should be but 1 next to other,pretty far from eachother.....but i am sure taht at the begining toolpath didnt show that move cos it went totaly out of 1x1 inch square toolpath...
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If it happens again have a look and see if the DROs show where the tool is or if they still show where it should be.
Hood
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The only time the mill ( steppers ) here went on it's merry way and cut through something was due to missed steps.
You will here it when it happens.
It my case it was caused by having the velocity / acceleration set to high and not leaving any headroom for the machining.
So now run rather conservatively at about 30 to 40 % below max velocity and have never seen it happen since.
RICH
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i think my cnc is set on 700mm/min,and i was running on 70 to 100mm/min...and he was cleaning 0.1mm of surface on 1x1 inch piece and just continued straight for next 1/2 inch and sloped down like a shovel.......i dont think he missed any step before......guy that made my cnc told me that mach sometimes just does smthing strange...