Bed level very uneven  

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jason.c2
(@jason-c2)
Eminent Member

Hi all,

I have been using the printer for awhile now, and have managed to get things working well but one thing I seem to sill have issues with is the bed level. There seems to be a large difference between left and right and it's way more then the bed level correction adjustment can compensate for. Also with regards to that adjustment when I put in a value + or - is relative to the bed or the nozzle? in other words does + move the nozzle further way or closer? Forgive me if that is dumb but i have tried adjusting this with not much success. And I am wondering if it's my assumptions on direction. However even so it still does not seem to be enough.

It seems like I have a sweet spot for printing that is on the left side of the bed. If I try to do a large print or print multiple things that go to the right side I always have issues with the first layer not sticking because the z calibration is way off on that side. Any thoughts? I am talking about a 100 - 150um difference which to me seems like a lot.

Anything I should check in my build?

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Posted : 02/12/2016 3:16 am
JohnOCFII
(@johnocfii)
Estimable Member

Any thoughts? I am talking about a 100 - 150um difference which to me seems like a lot.

Anything I should check in my build?

Take a metal flat edge or metal ruler. Hold it upright. Lay it across your bed. Place a flashlight behind it. See if the light shines through. Do this at different places on the bed. Take photos. Post them here. Then, do a Live chat with support, and point them at the note here with your photos.

If it is as bad as you say, they may be able to help.

John

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Posted : 05/12/2016 5:09 am
Nigel
(@nigel)
Honorable Member

Check squareness with axis, it is a right angled triange across X Y and Z. Check levels left and right above the bed Z, and front and back Y and left and right X. The build should be at right angles. Any slight scew and bed height can be corrected by the nine axis bed levelling. Perfect alignment in the build helps a lot. did you top out the Z axis to the stops at the top and grind them a bit left and right, in the alignment process? Both sides need to hit the top. The noise can be disconcerting but does no harm. Both sides need hit the top and top out.

Nigel
Life is keeping interested and excited by knowledge and new things....
Posted : 05/12/2016 5:59 am
jason.c2
(@jason-c2)
Eminent Member

Any thoughts? I am talking about a 100 - 150um difference which to me seems like a lot.

Anything I should check in my build?

Take a metal flat edge or metal ruler. Hold it upright. Lay it across your bed. Place a flashlight behind it. See if the light shines through. Do this at different places on the bed. Take photos. Post them here. Then, do a Live chat with support, and point them at the note here with your photos.

If it is as bad as you say, they may be able to help.

John

Thanks John, I have done this and will post the pics .

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Posted : 10/12/2016 5:51 pm
jason.c2
(@jason-c2)
Eminent Member

Check squareness with axis, it is a right angled triange across X Y and Z. Check levels left and right above the bed Z, and front and back Y and left and right X. The build should be at right angles. Any slight scew and bed height can be corrected by the nine axis bed levelling. Perfect alignment in the build helps a lot. did you top out the Z axis to the stops at the top and grind them a bit left and right, in the alignment process? Both sides need to hit the top. The noise can be disconcerting but does no harm. Both sides need hit the top and top out.

Hi Nigel,

Yes I did the correct z axis calibration, I definitely hit the top on both sides. When I do the XY calibration in the firmware it tells me my x and y are perfectly perpendicular. I am posting pics as the John has suggested, feel free to take a look and let me know what you think.

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Posted : 10/12/2016 5:55 pm
jason.c2
(@jason-c2)
Eminent Member

UPDATE with Photos.

I took photos from two locations across the bed, front and back. There are three photos at each location left, right and center. This post is the front.

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Posted : 10/12/2016 6:00 pm
jason.c2
(@jason-c2)
Eminent Member

UPDATE with Photos.

This post is the back.

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Posted : 10/12/2016 6:01 pm
nicholas.b2
(@nicholas-b2)
Trusted Member

My outsides were slightly higher so used some old motherboard fibre washers to raise them up slightly. I would say that the centre line in yours may be getting pulled down by the central screws holding the bed. If you loosen them, does it go straight?

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Posted : 10/12/2016 8:49 pm
jason.c2
(@jason-c2)
Eminent Member

My outsides were slightly higher so used some old motherboard fibre washers to raise them up slightly. I would say that the centre line in yours may be getting pulled down by the central screws holding the bed. If you loosen them, does it go straight?

Actually, I just replaced my Y axis bearings (it was making a lot of noise at high speed) and I noticed there was a lot of play in the right side compared to the left. I am running some calibration tests now and things seemed to have improved. It is still low on the right side but not as much. The bed level corrections should be enough to correct it. We shall see... that's a good idea about the motherboard washers though...

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Posted : 11/12/2016 1:45 am
JohnOCFII
(@johnocfii)
Estimable Member

The bed level corrections should be enough to correct it. We shall see... that's a good idea about the motherboard washers though...

Overall - your bed seem pretty good compared to some photos I've seen.

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Posted : 11/12/2016 4:52 pm
jason.c2
(@jason-c2)
Eminent Member

Wanted to post an update to this thread in case anyone comes across it and has a similar issue.

I was flipping through the 3D Printing Manual that came with the printer, not the assembly instructions but the handbook. On the last few pages there is an FAQ. In there they list this issue (although not 100% the same it's similar). The reason they state in the handbook has to do with your Y carriage not being square. So what I did was remove the Y carriage completely as suggested in the book and square it up. After reassembly and re-calibration the issues seems to be much improved. No need to shim up the side with 3D printed washers.

I would suggest that anyone who buys the MK2 as a kit read the manual cover to cover. There is a lot of useful info there.

J.

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Posted : 28/12/2016 5:00 am
david.b14
(@david-b14)
Honorable Member

This just a tip / fact. I have not been having issues with my bed but I still wanted to know what the point on the bed is the most flat from point A to point B.

On one of the z axis stepper motors on the base where the rod meets the black part, I put a small sticker there.

Then do two prints that are 1 to 3 layers.

1) Concentric squares.

2) Concentric circles.

You can visually get an idea of the the area of the bed that is the most flat by seeing how little the Z steppers move. You could then give each square a measurement in radians / degrees to determine the optimal place to a print. This applies for smaller objects that will only cover 1 or 2 square markings on the print bed.

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Posted : 28/12/2016 1:43 pm
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