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New kit, can not calibrate.  

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nemosarms
(@nemosarms)
New Member
New kit, can not calibrate.

I have a newly assembled kit. Everything looks right on all the check lists. When I attempt to run the wizard for the first time the machine is failing on the Z calibration. However I think my issue has nothing to do with the Z axis. When I auto home (or run the Z calibration) the PINDA sensor does not look like it is where the machine think it should be. It does not line up with the circle, it is about 6mm off on the X and 4 mm on the Y if I zero it on the circle by eye. I have downloaded the newest firmware and reflashed it and have the same issue with things not lining up. The Self test runs and passes. I just can not get the Z calibration on the first point. I have adjusted the PINDA up, down and every way I can possibly move it trying to get it to see just the first point. If someone can help me I would greatly appreciate it as I have been fighting this for way too long now. I have some 3d printer experience but this is my first PRUSA. I have to admit I am disappointed that I can not get this working, and to that end the contact button on the PRUSA site does nothing but give suggestions. The submit button does nothing. Only information I can already find / have is there proving to be not a contact system at all. This printer is more than double the price of any of the of the others I have purchased and the is the first one I have not been able to assemble and get up and running without support (which is not working for whatever reason.

Posted : 27/07/2019 4:16 am
Dave Avery
(@dave-avery)
Honorable Member
RE: New kit, can not calibrate.

log in to the prusa shop , there will be a chat button in the bottom right corner of the page.   

the printer homes by sensing the motors hitting the end of travel if anything obstructs the travel near the end the printer will misshome. 

if you are off in X make sure the extruder can travel all the way to the left and hit the X axis block, fan wires or screws not completely seated are common problems

 

on the Y axis make sure the bed con move all the way to the back and the left rear bearing can hit the rail mounting block

Z calibration can be off if the top mount blocks are not totally seated on the Z axis rails or the Z rails are not totally seated in the motor mount blocks

 

 

This post was modified 2 years ago by Dave Avery
Posted : 27/07/2019 4:42 am
nemosarms
(@nemosarms)
New Member
Topic starter answered:
RE: New kit, can not calibrate.

Thank you David for pointing me at the chat instead of the contact us option. I am in line now.

As for the x and y it looks like there is over movement, not restriction. The PINID is left 6mm and forward 4mm of where the circle on the bed is when preparing to calibrate the Z axis moving uo then down. I checked movement on all sides and made sure that nothing is interfering with any axis movement. It fails on the first z every time.

Posted : 27/07/2019 4:57 am
Dave Avery
(@dave-avery)
Honorable Member
RE: New kit, can not calibrate.

the Z calibrate sequence is:

move to top 

run motors to jam both nuts into the top stops ( level up the X axis with the top stops)

move down to a couple of mm above the bed

move in a circle while slowly lowering the z axis looking for the pinda to detect the alignment pad (as long at the circle passes over the pad it will calibrate)

move in front of the pad and sweep back and forth while moving to the rear. when the pinda triggers move up till it stops and keep sweeping ( building a xyz map of pad sensing)

move to the middle of the detected pad andmake diagonal moves to detect center

and repeat for the other 3 pads

if the Z axis is too long it will never get low enough to trigger the pinda

you can watch the pinda top led to see if the triggers off

Posted : 27/07/2019 5:16 am
nemosarms
(@nemosarms)
New Member
Topic starter answered:
RE: New kit, can not calibrate.

Mine goes up to the top, does the clicks and comes straight down on the bed offset as stated from the front left point and fails immediately. It never gets close enough horizontally to pick up the point. If I manually adjust it I see the light go off and on as I move over the spot. After the vertical motion (straight up then straight down) it fails. There is no spiraling going on at all for me.

Posted : 27/07/2019 5:24 am
Darrell
(@darrell)
Eminent Member
RE: New kit, can not calibrate.

Not sure if this is the same problem that I had when I first got mine, but just before running the calibration, I had to move the assembly all the way to the left by hand.  Nowhere did it say to do this in the instructions, but once I did, it worked correctly. 

Posted : 29/07/2019 4:35 pm
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(@)
Illustrious Member
RE: New kit, can not calibrate.
Posted by: The Trek Nerd

Not sure if this is the same problem that I had when I first got mine, but just before running the calibration, I had to move the assembly all the way to the left by hand.  Nowhere did it say to do this in the instructions, but once I did, it worked correctly. 

All you did by this action was bend the wire harness a bit so it was no longer preventing the extruder from homing.

Posted : 29/07/2019 9:30 pm
Darrell
(@darrell)
Eminent Member
RE: New kit, can not calibrate.

No wires were keeping anything from going left - it simply didn't even try.  It thought wherever it was sitting was 0,0 even if it was in the middle of the bed, so it failed first thing.  I had to put it at actual 0,0 so when it went looking for the points, it could find them.

Posted : 29/07/2019 9:41 pm
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 --
(@)
Illustrious Member
RE: New kit, can not calibrate.

When the printer starts up after a power on, 0,0,0 is wherever the extruder is sitting.  No mystery there.  If after a home command it wasn't moving and wires were not the issue, the motors were still in a stalled state and probably couldn't move the extruder due to something like stiction.  Forcing it by hand broke the stiction.  In this case perhaps insufficient lubrication or perhaps the extruder housing is pinching the bearings -- other known issues.

G28 W tells the motors to move until they stall.  If they don't move, the firmware has detected they are over-current and thinks they are already stalled.  Dry bearings are one common cause.  Overtightened bearings retainers another. 

To reiterate: you do not need to move the extruder to a stop to get the printer to work... there is simply no mechanism in the firmware logic where that would make any difference at all... unless your action overcame a mechanical difficulty or build problem.  If the G28 command fails, then you have a hardware problem. It really is that simple.

 

Posted : 29/07/2019 10:19 pm
nemosarms
(@nemosarms)
New Member
Topic starter answered:
RE: New kit, can not calibrate.

My issue was with the PINDA being a fraction off. I adjusted it 20 times on my own before I contacted support. Of course it worked the first time once I have them on the line like magic. Or maybe it felt my vibes and shook itself into place. But since then Mostly happy news. I printed a nice bottle opener (with a strange sensor filament bug on the change the first time and not again since), onto the Low res frog then the higher. I have to say I was a little disappointed with the quality of the print. Factory Gcode on the card provided with the printer. But after downloading the model myself and tweeking settings just so I was able to produce something much nicer. And to boot I stuck some really flexible PLA I expected to go horribly. I was extremely surprised with the setting suggested by Maker's Muse to have 3 octos come out and then I did the frog which also came out fantastic. I am have some issues with certain models and will be asking you guys for some advice as to how to improve them (mostly circular prints with a taper showing extrusion spots on the outside layer where it starts, I've used negative retract to the point of print failure as well as coast without success) . I just wanted to update for those of you who helped me out that indeed you put me on the right track and support was very good once the correct method of contact was point out to me. (Thanks again David-66). And thanks to all, I wrote that post after a very stressful few days and finishing the printer on a 26 hour work day to have it not work :O

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This post was modified 2 years ago by nemosarms
Posted : 30/07/2019 1:07 am
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