Bed Leveling Constant Issue

I have been fighting with leveling my bed for quite some time now and I am at a loss now. My bed is a piece of ATP-5 and its 327mm x 327mm and I have a 300mm x 300mm silicone heat pad on the bottom. The issue that I keep having is the corners are never level. I go through the same process of leveling the center with a piece of paper and them I go to each corner and try and level them and I just keep chasing my tail. I go to one corner and level it with a piece of paper then go to the opposite corner and attempt to level it and it then throws the opposite corner back out of level. I go through this vicious cycle and its madding! I did have some flex in my X axis using 8mm rods but I have recently reworked my X axis to have 10mm rods and the play in my X-carriage is now gone but I still continue to have bed leveling issues. Any help would be great!! Thanks in advance!

... a simple workaround is to print "washers" directly above every screw, then place them beneath the bed ... this raises the bed according to the washer-heights

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Viktor
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I am not familiar with CoreXY systems but it sounds like you have screwjacks at each corner: The diagonally opposite corners fight with one another as in the diagram below



While the diagram applies to a Prusa type machine, the same applies to anything with adjustments in each corner. To get around the fight-off between the corners, adjust each corner first to the same height then check the middle and only tweak gently. If it needs more than gentle tweaking then the problem is more serious - like a bent plate or frame. In the diagram, the lower plate is often called a "squashed frog" and the flexible legs are semi-rigid parts to flex instead of the plate bending: This is known variously as an "engineering compromise" or "kludge"

A better way of doing it would be to have a method with only three adjustments.

Mike

[drmrehorst.blogspot.com]

[drmrehorst.blogspot.com]

[drmrehorst.blogspot.com]

[drmrehorst.blogspot.com]

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

On the three point mounts does it matter where the 3 points are? Can I do 2 up front and 1 in the back?

They can be anywhere (except collinear!) but it is most convenient in terms of leveling if two of them (reference and pitch) lie on a line parallel to either the X or Y axis of the printer. You set the reference screw to put the bed at the height you want (you may not need to touch it at all depending on how your Z=0 adjustment works), then adjust pitch first, and finally roll to level the bed. Adjusting the roll screw does not affect the pitch of the bed, so always adjust pitch first, then roll. Finally, set Z=0 by whatever method your printer uses.

Edited 1 time(s). Last edit at 08/19/2019 02:22PM by the_digital_dentist.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Ok looking at my current setup how would I go about setting up the 3 point leveling. Looks like I would need to rework my entire bed configuration.

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556duckvader
On the three point mounts does it matter where the 3 points are? Can I do 2 up front and 1 in the back?

If your printer runs RepRapFirmware and you use the bed levelling assistant in firmware, they can be anywhere you like except collinear, because you tell the firmware the coordinates of the screws and after probing the bed it tells you the amounts to adjust them. BTW it can do that for 4 levelling screws too, but that will only work if the bed is flexible enough to twist slightly.

If you use manual means to level the bed, then it will be easier for you if 2 of the screws have the same Y coordinate or the same X coordinate. For example, the two front corners and the back centre.

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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].

It looks like you have 6 holes in the bed- the four corners and two at the centers of opposite sides. In that case, use two of the corner screws on one side of the bed for pitch and reference and use the center hole on the opposite side for the roll adjuster.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

I have used the manual bed leveling assistant in reprap firmware, and it's great! It tells you exactly how far off each screw is and exactly how much to turn them to correct the error.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Looking at the ATP-5 bed and printer built, I am pretty sure it is the only thing that is square, flat and stays that way during "adjustment". Prusa table pictured above unlikely applies.

An other thing, a flat bed is not enough, the nozzle tip must also travel in a plane and this one depends on the X Y guides.

ABL may be the only way as it can compensate/hide all this.

Edited 1 time(s). Last edit at 08/21/2019 09:06AM by MKSA.

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