Re: First print NEED ADVICE May 04, 2015 03:35PM |
Registered: 10 years ago Posts: 770 |
The picture shows 3- 15/16"Quote
Ralphy
The prints z axis error is about twice. A 2" tall obeject prints out 2 15/16"
Re: First print NEED ADVICE May 04, 2015 04:48PM |
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Re: First print NEED ADVICE May 04, 2015 06:00PM |
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Re: First print NEED ADVICE May 04, 2015 07:52PM |
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Re: First print NEED ADVICE May 04, 2015 09:39PM |
Registered: 8 years ago Posts: 69 |
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ggherbaz
If that print came out of 2031 instead of a 4000 range number and your printer have M5 threaded rods, even though it looks great it's not micro stepping right and you might be loosing quality.
Check your ramps board under the Z axis driver for all the jumpers, you should have 3 for full micro stepping.
Re: First print NEED ADVICE May 05, 2015 12:19AM |
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Re: First print NEED ADVICE May 05, 2015 12:28AM |
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Re: First print NEED ADVICE May 05, 2015 01:41AM |
Registered: 8 years ago Posts: 69 |
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ggherbaz
The problems is this: a 1.8 degrees stepper takes 360/1.8=200 steps per revolution, if you micro step you got 16 micro steps per full step so 200x16=3200 micro steps for a full turn. A full turn of an M5 screw is 0.8mm so for 1mm you need 4000 micro steps. A 2031 is most likely half stepping at best.
Re: First print NEED ADVICE May 05, 2015 01:42AM |
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Re: First print NEED ADVICE May 05, 2015 07:38AM |
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Re: First print NEED ADVICE May 05, 2015 01:02PM |
Registered: 8 years ago Posts: 69 |
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JamesK
Hi Ralphy,
ABL is auto bed levelling where the printer uses a probe to measure the height of the bed at various points and then compensates for any tilt by moving the head in Z during each layer. It's very convenient and makes great sense for delta style printers where all three axis are in motion all the time. I'm not so sure it's the best approach for printers like the Prusa i3 which were built with the assumption that during printing Z would move steadily upward and could therefore use a relatively crude Z axis implementation.
Getting back to the mysterious doubling of Z, being out by a factor of 2 suggests that it's running with 8x stepping instead of 16x. Given that it's recommended to use Z layer heights that are a multiple of full steps, that's not going to be a problem (unless you use the auto bed levelling as ggherbaz pointed out), so I wouldn't worry too much. Long term I'm sure you'd like to get to the bottom of it. Given that you've checked the jumpers the most likely explanation is a bad solder joint on the path between the jumper and the chip's IO pin. You could try following the path and checking each solder joint, or you could order a spare ramps board to swap in (I guess the problem could also be on the arduino board, so you might need one of each).
Jim
Re: First print NEED ADVICE May 05, 2015 01:26PM |
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Re: First print NEED ADVICE May 05, 2015 03:20PM |
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Re: First print NEED ADVICE May 05, 2015 03:47PM |
Registered: 8 years ago Posts: 69 |
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ggherbaz
One thing to note: I have seen jumpers without the metal inset and wrong size jumpers, so just the presence of the jumper doesn't mean that they are doing their function. I will recommend you to use a multimeter and check that the pins are actually connected by the jumper. You can swap jumpers from the other working axis to test them too.
I don't know if it is possible, but if for any reason the pin layout was modified in the firmware, the controller may discard or misunderstand the micro stepping. You can try a fresh Marlin firmware to see if that fix the problem, but that it's last resource.
If you come to the conclusion that it is a board issue (cold solder or broken trace) you should contact Folgers tech with some photos of the broken trace and or cold solder spot and request a replacement, I don't see no reasons why they will not honor some manufacturers defect replacement.
Re: First print NEED ADVICE May 05, 2015 04:17PM |
Registered: 8 years ago Posts: 1,873 |
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The z axis rise is not making the noise now with the 2031 setting but it did before with the 4000 setting.
Re: First print NEED ADVICE May 05, 2015 04:22PM |
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Re: First print NEED ADVICE May 05, 2015 04:47PM |
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Re: First print NEED ADVICE May 05, 2015 07:00PM |
Registered: 8 years ago Posts: 69 |
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JamesK
You can check the voltage at the pins on the stepper driver. Are you using A4988s? If so, MS1, 2 and 3 should all be high for 16x microstepping (according to [www.pololu.com]). If MS3 is low that will explain the factor of 2 you are seeing. If all three are high then maybe it's a faulty driver - you could try swapping them around and see if the problem migrates to a different axis.
If you are using 8825s then it should be low low high for 16x, high high low would give you 8x again (https://www.pololu.com/product/2133).
I'm not sure what the recommended vref for Z is, but if it's moving smoothly now I guess you're good.
Re: First print NEED ADVICE May 05, 2015 08:57PM |
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I guess its micro stepping at 16x with the 2031 setting.....weird
Re: First print NEED ADVICE May 05, 2015 09:26PM |
Registered: 8 years ago Posts: 69 |
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ggherbaz
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I guess its micro stepping at 16x with the 2031 setting.....weird
No, it means that the problem might be in the driver itself or in the signal sent from the board.
Now it will be a good time to swap drivers with another axis and test. If the problem is in the driver, wherever you move it too will show the issue if its stays in Z then a reflash of the firmware might be recommended (be sure to save all the values so you can transfer them to the new firmware).
Re: First print NEED ADVICE May 05, 2015 09:37PM |
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Re: First print NEED ADVICE May 05, 2015 09:47PM |
Registered: 8 years ago Posts: 69 |
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ggherbaz
You are correct.
Good luck and let us know your progress.
Re: First print NEED ADVICE May 05, 2015 10:43PM |
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Re: First print NEED ADVICE May 06, 2015 08:51AM |
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