Machsupport Forum
G-Code, CAD, and CAM => LazyCam (Beta) => Topic started by: bobskolnick on March 11, 2007, 10:25:54 PM
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I have been having some problems with my Z axis. I use LazyCam to import a JPEG and convert it to G-Code. I load the code into the Mach 3 Controller. About half way through the cutting process I notice that my cutter is no longer in the material. It looks like the cutter has been slowly ramping in the positive Z direction. If I look at the Z axis during the engraving process it is moving up and down the way I would expect, but it must be slowly incrementing itself in the positive (upward) direction. However if I look at the Z axis DRO it is indicating a negative value which would seem to indicate that the cutter should be in the material. Am I missing a setting? I am confused. Any suggestions?
I am using the following software versions:
Mach 3: Version R2.0.024
LazyCam: 2.00.032 Standard Edition
Thanks.
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Tell us more about your set up. Is it a mill, router, etc.? Is it skipping steps, tool pushing up in the spindle? spindle moving up? Also, post your g-code.
Brett
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I am in the process of building a 3 axis gantry type cnc router. The motor drivers are Gecko 340 and I am using them with DC Brush type motors. All three axes use acme leadscrews and circular rails with plain sleeve bearings; although I think I am having problems with stiction and will probably change over to ball bushings. The spindle I am using is a Rotozip or a Porter Cable 690 Router.
I don’t think it is skipping steps because the error checker on the servo drivers don’t let me operate unless the feedback from the encoder is within some allowable error.
I checked the tool, spindle and the hardware and it all appears to be tightened down. I measured some positions and made some tool marks to see if anything is slipping but it does not appear to be.
After giving it some more thought I think the problem might be the shaft couplings. I am using jaw type couplings so it easy to take the motors on and off, but these type couplings have backlash in them. Since the Z axis is moving up and down with such a high frequency I think the backlash error is adding up slowly and therefore giving me a tool offset error. I am going to try and switch to a rigid coupling or a beam type coupling.
Any thoughts?
Thanks again.
Regards,
Bob
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Hey Bob,
Sounds like a good place to look. No, I don't think you are skipping steps since you are running servos. If it starts off at the right depth and gets shallower the longer you run it, I would think you defiantly have a slipping problem. Do you know how to check your steps per and make certain they are right? Can you post the code you are running?
Brett