Homing problem
Posted by Fpex
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Homing problem August 04, 2015 03:46AM |
Registered: 9 years ago Posts: 395 |
I have been forced to do an almost rebuilt of the ormerd2 due to cracks on the z axis plastics and supply + duet failure. Now I experience something I either did see in my first built or I totally forgot about. When homing the head crashes against the z axis and keeps pushing. Occasionally it will calibrate in the white spot nearby before crashing against the axis. Because I have a new duet, I am back to latest RRP firmware and not dc42 yet.
Edited 1 time(s). Last edit at 08/04/2015 03:46AM by Fpex.
----- Making the world smarter @ www.xetal.eu
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Edited 1 time(s). Last edit at 08/04/2015 03:46AM by Fpex.
----- Making the world smarter @ www.xetal.eu
----- Helping entrepreneurs @ www.fralke.com
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Re: Homing problem August 04, 2015 04:26AM |
Registered: 10 years ago Posts: 14,672 |
Quote
Fpex
I have been forced to do an almost rebuilt of the ormerd2 due to cracks on the z axis plastics and supply + duet failure. Now I experience something I either did see in my first built or I totally forgot about. When homing the head crashes against the z axis and keeps pushing. Occasionally it will calibrate in the white spot nearby before crashing against the axis. Because I have a new duet, I am back to latest RRP firmware and not dc42 yet.
Sounds like the proximity sensor is not triggering when it is over the X homing tab. Have you tested the proximity sensor? Did you put a piece of white paper or tape on top of the tab? How high above the tab is the proximity sensor? If it is too far away to trigger, you could glue e.g. white card in top of the tab to bring it nearer to the sensor.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Homing problem August 04, 2015 04:31AM |
Registered: 8 years ago Posts: 443 |
Are you using orthogonal compensation?
I experienced similar problems, found there was something screwy with the homing.........I would be interested to know the results of this test
1) from startup home the X and Y axes in the order of XY and note the XY=0 position, if you haev calipers maybe measure the axes positions from a fixed point
2) turn off machine and repeat but in order YX
3) is there a visible or measurable difference between the two home positions?
4) remove the orthogonal compensation from your Config file and try again
Edited 1 time(s). Last edit at 08/04/2015 05:35AM by bgkdavis.
I experienced similar problems, found there was something screwy with the homing.........I would be interested to know the results of this test
1) from startup home the X and Y axes in the order of XY and note the XY=0 position, if you haev calipers maybe measure the axes positions from a fixed point
2) turn off machine and repeat but in order YX
3) is there a visible or measurable difference between the two home positions?
4) remove the orthogonal compensation from your Config file and try again
Edited 1 time(s). Last edit at 08/04/2015 05:35AM by bgkdavis.
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Re: Homing problem August 04, 2015 04:32AM |
Registered: 9 years ago Posts: 395 |
mm ., it could be that the starting point is too high or it is the kapton on top of the paper. It used to work, but this is a different kapton manufacturer I used to use before the crash. I will check with some paper. Thanks,
----- Making the world smarter @ www.xetal.eu
----- Helping entrepreneurs @ www.fralke.com
----- Making the world smarter @ www.xetal.eu
----- Helping entrepreneurs @ www.fralke.com
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Re: Homing problem August 04, 2015 04:33AM |
Registered: 9 years ago Posts: 395 |
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Re: Homing problem August 04, 2015 06:47AM |
Registered: 10 years ago Posts: 14,672 |
Quote
bgkdavis
Are you using orthogonal compensation?
I experienced similar problems, found there was something screwy with the homing.........I would be interested to know the results of this test
1) from startup home the X and Y axes in the order of XY and note the XY=0 position, if you haev calipers maybe measure the axes positions from a fixed point
2) turn off machine and repeat but in order YX
3) is there a visible or measurable difference between the two home positions?
4) remove the orthogonal compensation from your Config file and try again
I believe that's a symptom of a bug I fixed in my fork many months ago. The fix found it's way to the official 1.09 RRP firmware eventually via zpl's fork.
Edited 1 time(s). Last edit at 08/04/2015 06:47AM by dc42.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Homing problem August 04, 2015 06:50AM |
Registered: 8 years ago Posts: 443 |
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Re: Homing problem August 04, 2015 07:15AM |
Registered: 9 years ago Posts: 395 |
how?
anyhow, i see that even with paper the sensor does not stop and goes against the z axis. Wiring is fine.
the sensor raises always about 1cm before moving.
Edited 1 time(s). Last edit at 08/04/2015 07:17AM by Fpex.
----- Making the world smarter @ www.xetal.eu
----- Helping entrepreneurs @ www.fralke.com
anyhow, i see that even with paper the sensor does not stop and goes against the z axis. Wiring is fine.
the sensor raises always about 1cm before moving.
Edited 1 time(s). Last edit at 08/04/2015 07:17AM by Fpex.
----- Making the world smarter @ www.xetal.eu
----- Helping entrepreneurs @ www.fralke.com
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Re: Homing problem August 04, 2015 07:30AM |
Registered: 8 years ago Posts: 26 |
This sounds the same as happened with my new Ormerod. The config.g file as delivered has the line G31 Z0.8 P600 which as I understand it the z axis goes down until the sensor reads 600 and then descends another 0.8mm. Unfortunately with my sensor sensitivity 0.8mm meant it was trying to go below the bed. After going through the full Z probe calibration I ended up with G31 Z0.9 P573 which has reliably worked.
I never got the sensor above 890ish when actually touching a piece of white paper so I'm not convinced the RepRap instructions are correct for at least my sensor, and maybe yours.
I never got the sensor above 890ish when actually touching a piece of white paper so I'm not convinced the RepRap instructions are correct for at least my sensor, and maybe yours.
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Re: Homing problem August 04, 2015 07:37AM |
Registered: 9 years ago Posts: 395 |
I will give it a try, thanks.
I also had to change sensor actually in my rebuilt, so maybe it is different form the older one.
UPDATE: thanks, it must be a difference in sensor. IT worked by changing the standard parameters. I use G31 Z0.7 P570
Edited 3 time(s). Last edit at 08/04/2015 08:51AM by Fpex.
----- Making the world smarter @ www.xetal.eu
----- Helping entrepreneurs @ www.fralke.com
I also had to change sensor actually in my rebuilt, so maybe it is different form the older one.
UPDATE: thanks, it must be a difference in sensor. IT worked by changing the standard parameters. I use G31 Z0.7 P570
Edited 3 time(s). Last edit at 08/04/2015 08:51AM by Fpex.
----- Making the world smarter @ www.xetal.eu
----- Helping entrepreneurs @ www.fralke.com
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Re: Homing problem August 06, 2015 04:10AM |
Registered: 9 years ago Posts: 395 |
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Re: Homing problem August 06, 2015 11:13AM |
Registered: 10 years ago Posts: 2,472 |
Quote
Fpex
While homing works, the Z0 is now almost 2cm too high ....
2cm is far too high - do you not mean 2mm?
You must adjust the trigger height in the G31 command in your config file to whatever height it triggers (the G31 Z parameter). Fine-tune that parameter until it homes with the Z zero height correct. Enter the G31 command by hand then re-home Z until the zero height is correct, then change the value in your config file. e.g. you say you are presently using G31 Z0.7 P570. If Z0 is exactly 2mm too high, enter G31 Z2.7 P570 and it will home correctly. Only the P parameter affects the X endstop trigger, so changing Z will not affect X homing.
Dave
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Re: Homing problem August 06, 2015 12:05PM |
Registered: 9 years ago Posts: 395 |
Nope about 2cm too high ..... the first time i built it, it was all fine with the standard setting ... not sure what happened after the rebuilt.
I will recalibrate next time i have time, but 2cm is huge !!
----- Making the world smarter @ www.xetal.eu
----- Helping entrepreneurs @ www.fralke.com
I will recalibrate next time i have time, but 2cm is huge !!
----- Making the world smarter @ www.xetal.eu
----- Helping entrepreneurs @ www.fralke.com
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Re: Homing problem August 06, 2015 02:40PM |
Registered: 9 years ago Posts: 638 |
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Re: Homing problem August 06, 2015 05:23PM |
Registered: 9 years ago Posts: 395 |
Yes my rod was cracked and it has been fixed and the effect compensated by manually tune the bed also. Replacing it again is a real pain!! And if I have to, I rather redesign the piece into something stronger than the current design as this is the weak spot of the ormerod in my view,
No idea what is going on, but in homing it does get to the right position ... Till the very end when it decides to move up. I will calibrate it down and see how all will behave.
----- Making the world smarter @ www.xetal.eu
----- Helping entrepreneurs @ www.fralke.com
No idea what is going on, but in homing it does get to the right position ... Till the very end when it decides to move up. I will calibrate it down and see how all will behave.
----- Making the world smarter @ www.xetal.eu
----- Helping entrepreneurs @ www.fralke.com
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