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Offline kolias

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Re: Strange Results
« Reply #20 on: October 11, 2009, 08:18:34 PM »
Thank you Gerry

Like a beginner, I never thought to check the DRO’s and so I don’t know, sorry.

I tend to agree that it may be a mechanical problem because I read the LC manual and as far as I know I do all the inputs correctly. I also looked at the code and never saw anything more than Z-0.0625”

I have checked all my mechanical connections and they all seem to be tight and nothing is missing. When the CNC is not working and I try to physically move by hand the Z axis it is solid like a rock

Are you able to point to something specific for me to check?

Nicolas
Nicolas

Offline Chaoticone

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Re: Strange Results
« Reply #21 on: October 11, 2009, 08:52:28 PM »
Maybe the z axis is skipping steps when it trys to retract the z. Might tune the motor down on the z to 50% of present accel and vel and see if that helps for a quick test.

Brett
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Offline kolias

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Re: Strange Results
« Reply #22 on: October 11, 2009, 09:04:58 PM »
Maybe the z axis is skipping steps when it trys to retract the z. Might tune the motor down on the z to 50% of present accel and vel and see if that helps for a quick test.

Brett

Sounds Good Brett, I will try that tomorrow.

Thinking again, I believe it's more of a software problem than mechanical. On the last file I was working (tulip22) the Z axis went down 1/2" in about a couple of seconds before I hit the Estop. I dont think a mechanical problem will have created that

Nicolas
Nicolas

Offline RICH

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Re: Strange Results
« Reply #23 on: October 11, 2009, 09:27:09 PM »
Can you post a pic of your machines Z axis.
 I don't think it's a sofware problem.

DO you zero out the Z axis before running the program?

Take a look at section 8.3.4 and also Tutorial #6 section 1.0 Plunge Cearance in the manual to make sure
your not doing somehing wrong in LC.

RICH

Offline kolias

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Re: Strange Results
« Reply #24 on: October 11, 2009, 11:21:48 PM »
Can you post a pic of your machines Z axis.
 I don't think it's a sofware problem.

DO you zero out the Z axis before running the program?

Take a look at section 8.3.4 and also Tutorial #6 section 1.0 Plunge Cearance in the manual to make sure
your not doing somehing wrong in LC.

RICH

Thank you RICH

Yes I always zero the DRO’s before running the program

Section 8.3.4 refers to the cuting parameters: I always set the Rapid height to 1.0000, Cut start 0.0000 and Cut depth to -0.0625 or -0.1250 and used to work before very good.

Tutorial #6 Plunge Clearence describes very well the cutting parameters and I always follow them. The proof is that the program starts well but after a few lines the cutting depth increases drastically and that is what I would like to find out why

Here are some pics of the Z axis

Nicolas
Nicolas

Offline kolias

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Re: Strange Results
« Reply #25 on: October 11, 2009, 11:43:04 PM »
When I say that I think it may be a software problem, I dont mean LC. I mean that I may be doing something wrong with my paramaters or I may have change some parameter(s) before which I now forget.

Nicolas
Nicolas

Offline kolias

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Re: Strange Results
« Reply #26 on: October 12, 2009, 03:24:08 PM »
Maybe the z axis is skipping steps when it trys to retract the z. Might tune the motor down on the z to 50% of present accel and vel and see if that helps for a quick test.

Brett

The Z axis was at 48 Vel and 8 Acc. I decreased the Vel to 24 and Acc to 4 but the motor got stalling after she went down for a couple of inches. I played with the numbers a bit but the motor was getting stalled and so I put the same values as before BUT the motor was stalling again now!!! what a mess.

When I move the Z axis with the right / left arrow keys the axis works fine with all the above numbers but when I try to run a gcode she stalls. X & Y are fine.

Is it possible that “noise” may create the problem I have with the Z axis?

Nicolas
Nicolas

Offline kolias

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Re: Strange Results
« Reply #27 on: October 13, 2009, 01:45:48 PM »
My CNC seems that is working fine now but when she goes to line N45 the feed rate drops to almost 0”.

From line N10 to line N40 she is fast but then when she hits line N45 she goes very slow and the motors sound like you have a musical instrument playing.

When I move all axes with the keyboard, all is working fine and fast. All DRO’s working well and the motors are calibrated fine as far as I know.

From the attached files, can someone tell me if there is anything wrong?

Nicolas
Nicolas

Offline ger21

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Re: Strange Results
« Reply #28 on: October 13, 2009, 06:48:26 PM »
Increase the feedrate. You have it set to 15ipm in line N45 (F15.0)

I think we went over this before, but when you lower the accel and velocity and it stalls, it's probably due to resonance.

Also, when it cuts too deep, be sure to check the Z DRO and see what it says.

Most likely, the Z axis is stalling when it should be moving up. The cumulative affect is that the Z goes too deep.
« Last Edit: October 13, 2009, 06:50:40 PM by ger21 »
Gerry

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Offline kolias

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Re: Strange Results
« Reply #29 on: October 13, 2009, 06:59:46 PM »
Thanks Gerry, I will do that

The funny part is that with the same motor tuning and feed rate (F15) I did 6 pieces and all was fine. I dont know why now I have to increase the feed rate. Actually I had the feed rate before at F10 and the motors were never "singing" like the do now. 

Anyway what you said sounds good

Nicolas
Nicolas