erniehatt
Posts: 140
Joined: Fri Jul 24, 2015 5:31 pm

shifting layers

Fri May 06, 2016 4:29 am

Yes I have read previous articles on this subject , and I have checked for loose belts etc.
But what I am getting here is strange, I have tried printing the item, first up it was good, after that when I went to print it again, about half way through the layers jumped to the left, stopped the print, and tried again, the net time it shifted more to the back.
Any Ideas anyone.

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dkightley
Posts: 2339
Joined: Tue Mar 10, 2015 4:09 pm

Re: shifting layers

Fri May 06, 2016 8:50 am

Any Ideas anyone.
Only the recommendations here:
https://www.simplify3d.com/support/prin ... salignment
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net

erniehatt
Posts: 140
Joined: Fri Jul 24, 2015 5:31 pm

Re: shifting layers

Fri May 06, 2016 6:15 pm

Thanks Doug, I have a copy of that file, what puzzles me is if the belts etc are slipping then why not show that fact at the beginning of the print and not wait until it reaches a height of around 20mm.
I am using a bowden type configuration, and I am thinking that maybe as the Z axis rises it is causing pressure to build on the tubing which is effecting on the X axis, is this a possibility..

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dkightley
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Joined: Tue Mar 10, 2015 4:09 pm

Re: shifting layers

Fri May 06, 2016 7:56 pm

....what puzzles me is if the belts etc are slipping then why not show that fact at the beginning of the print and not wait until it reaches a height of around 20mm.
Perhaps the conditions that cause the actual slipping to take place don't happen until the print reaches the 20mm height! And it may not be the belt slipping....it could be the stepper motor "slipping" electrically.

What speeds do you have in your settings? Both printing and movement!
Have you tried slowing down the printing and/or movement speeds to see if the slipping stops?
Is there anything at or near the 20mm height in the model you are printing that would change the printing or movement speed?
Is there anything significant about the part at or around the 20mm height? A change in shape, etc
Is there any noise of any type from the printer at the point the layer shift takes place?
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net

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jimc
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Location: mullica, nj
Contact: Website

Re: shifting layers

Fri May 06, 2016 8:03 pm

there is another cause. are you running marlin firmware? if you are then there is a bug in the firmware or the arduino compiler. whatever it is the actual cause there is something that causes marlin and any arduino compiler above version 1.1.5 to not play nice together. if you compile it and upload with a newer version of arduino then you will get x and y skipping when running at high xy movement speeds. s3d default is 18000 which is too high and you will see the issue. its been proven and has been an issue for a long time. just download an old 1.1.5 version and upload with that.

erniehatt
Posts: 140
Joined: Fri Jul 24, 2015 5:31 pm

Re: shifting layers

Fri May 06, 2016 8:21 pm

thanks jimc, I look into it.

erniehatt
Posts: 140
Joined: Fri Jul 24, 2015 5:31 pm

Re: shifting layers

Sun May 08, 2016 10:04 pm

well I have tried just about everything.
I even changed the feed from bowden to direct , replaced the bearings on the X axis.
changed the speed, but as the speed got slower so the jumping happened much sooner.
I tried to hold the hotend to see if I could make the belt slip..
I am wondering, the extruder is dropping a globul here and there could it be hitting on of these. last thing I can think of.
Any more suggestions.

erniehatt
Posts: 140
Joined: Fri Jul 24, 2015 5:31 pm

Re: shifting layers

Mon May 09, 2016 9:09 pm

Oh well seems nobody like me has any further ideas, thanks all

MichaelHerron
Posts: 112
Joined: Mon Mar 16, 2015 2:36 pm

Re: shifting layers

Sat May 28, 2016 12:45 pm

erniehatt wrote:Oh well seems nobody like me has any further ideas, thanks all
A loose build plate could cause misalignment. If you have glass clipped onto a build surface, the glass could be shifting slightly during the build.

another cause could be a stepper-driver going bad. This has happened to me twice--with the same axis.

erniehatt
Posts: 140
Joined: Fri Jul 24, 2015 5:31 pm

Re: shifting layers

Sat May 28, 2016 4:54 pm

They are two very good points I never thought of.
At the moment I am in the throws of changing over to lead threads, but will certainly give it some thought if it still happens.

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