Another Bed Unlevel Post (front to back)  

Re: Another Bed Unlevel Post (front to back)

I have the same issue and I am working on in for quiet some time now.
Funnily enough I have taken the same steps to counter the problem.

I have bought some precision steel washers (0.1 mm and 0.2 mm) to try to level the bed.
I have taken the whole printbed apart several times now but to no avail.

What is weird to me is, that the manual bed corrections don't seem to have an impact at all.
I have lowered the back side to -50µm and the front side to +50µm but the squish is still identical.

I have also used a steel ruler to see if the bed is level.
If I measure from left to right there is almost no light coming through.
If I measure from front to back you can see a dent in the middle.

I have tried to counter that with additional washers, but the screws are not long enough as you mentioned before.
So I left those screws unscrewed and tried to print this way.

Still the problem persists with the front having way more squish than the rest.

I will see if I can take some pictures this evening (still at work right now).

Lets hope we can find a solution together!

Re: Another Bed Unlevel Post (front to back)

It looks as thought the line at the front is squished wider than at the back

full -50um in the front, 50um in the back

I believe that the -50 will lower the nozzle and cause a wider squish and the +50 at the back will raise the nozzle.

Try the other war round. +50 at the front and -50 at the back.

I do get confused with this, but I do think it works the same as live Z adjust - -ve is lower nozzle and +ve is higher.

Peter

Re: Another Bed Unlevel Post (front to back)

"-" will lower the nozzle "+" will raise the nozzle from the bed.
But as I said, no matter how I adjust that correction value it doesn't have an (noticeable) impact.

Re: Another Bed Unlevel Post (front to back)

"-" will lower the nozzle "+" will raise the nozzle from the bed.
But as I said, no matter how I adjust that correction value it doesn't have an (noticeable) impact.

Apologies; I was replying to Lance who initiated this thread and I think that was clear in the quote I used in my post.

If you wish to hijack someone else's thread, then you should not expect all answers to be addressed to you.

Peter

Re: Another Bed Unlevel Post (front to back)

"-" will lower the nozzle "+" will raise the nozzle from the bed.
But as I said, no matter how I adjust that correction value it doesn't have an (noticeable) impact.

Apologies; I was replying to Lance who initiated this thread and I think that was clear in the quote I used in my post.

If you wish to hijack someone else's thread, then you should not expect all answers to be addressed to you.

Peter

Hello PJR,

I wasn't trying to hijack this threat and I was aware of the fact that you were referring to Lance.
I merely wanted to support your claim on what happens with the nozzle in that case.

The purpose of my post was only to point out that it isn't working for me.
No bad intentions...

Phil

Re: Another Bed Unlevel Post (front to back)

Hi Phil

Apologies; I obviously misread your post.

Unfortunately, being only and unwell, I can only take in one thing at a time and I have to deal with situations in the same manner.

I will have a read through your post to see if I can help.

Peter

Re: Another Bed Unlevel Post (front to back)

Phil

You say that the centre is lower than the outside edges. Is that across the whole width of the bed? Do you have any indication as to the gap size (feeler gauges in the gap)? Is the gap still present when the bed is hot (60 degrees)?

Peter

Re: Another Bed Unlevel Post (front to back)

No harm done Peter 🙂

I have tested this with a warm and a cold bed - no change.
If you look at the printer from the side and place the ruler parallel to the y-axis, you have a high point on each side were the ruler rests.
Tightening the screws in the middle makes this way worse (obviously).

This only occurs in the y-direction tho, therein lies the problem.
If I put washers under the middle (at least 0.4 mm to get it right) the problem occurs in the x-direction (convex surface).
I do not have a feeler gauge unfortunately.

As soon as I get home I will put some pictures up.

Thanks in advance!

Re: Another Bed Unlevel Post (front to back)

Peter and Phil,

Thanks for the responses! I was a bit confused of the direction of the manual bed leveling from the definitions I have found. I will definitely flip when I get back home tomorrow from business. I am still worried that 50 um is a tad small for the issue I am having, but I will think positively! 😀 Really enjoying the problem solving though!

Until tomorrow!
-Lance

Re: Another Bed Unlevel Post (front to back)

Peter and Phil,

Thanks for the responses! I was a bit confused of the direction of the manual bed leveling from the definitions I have found. I will definitely flip when I get back home tomorrow from business. I am still worried that 50 um is a tad small for the issue I am having, but I will think positively! 😀 Really enjoying the problem solving though!

Until tomorrow!
-Lance

Re: Another Bed Unlevel Post (front to back)

Lance

You will be surprised by how much difference that 50 microns can make (and in this case we are talking 100 microns...)

But there is a way using the G80 command to implement up to 100 micron adjustments if you need it.

Peter

Re: Another Bed Unlevel Post (front to back)

Ok I am back at home and I've done some testing.

To start things off I have taken a picture of a print on my surface.

As you can see the lower squares are way more squished.
The next one is a closeup - don't mind the gap the nozzle left.

The following pictures will showcase the gap I have spoken about.
First two pictures are with washers:
X-axis

Y-axis

The next two pictures are without the washers:
X-axis

Y-axis

I have tightened the middle screws for both cases.
As you can see the gap is almost gone with the washers - but the screws are barely holding the bed.
Also the print is still squished more in the front.

What I have also measured is the distance from the bed to the z-axis with a depth gauge.
What i have found is that the bed is about 0.3 mm closer to the frame at the back.
Same goes for the frame itself, even though the zip ties are all tightened.
Sorry for the wall of text / photos. 😕

Re: Another Bed Unlevel Post (front to back)

Phil

The calibration squares you printed - are they with or without washers?

Looks like it will be easier to work without the washers.

Can you please do the following:

Remove any washers you have installed.
In the bed level adjustment, set Front, Left and right to +50 and the rear to +25

I have attached my calibration model which goes further into the corners. Can you please do the following:

Slice and print my model (no stirt or brim, just the initial priming line).
Take a photo from above and then mark each square in turn, where 0 is good, -5 is very over-extruded and +5 is very under-extruded.
Upload the picture for me to have a look at.

(Note: this is exactly what I did to get my bed to within a few microns over the whole surface. Hopefully, it will work for you too...)

Peter

Re: Another Bed Unlevel Post (front to back)

Phil

The calibration squares you printed - are they with or without washers?

Looks like it will be easier to work without the washers.

Can you please do the following:

Remove any washers you have installed.
In the bed level adjustment, set Front, Left and right to +50 and the rear to +25

I have attached my calibration model which goes further into the corners. Can you please do the following:

Slice and print my model (no stirt or brim, just the initial priming line).
Take a photo from above and then mark each square in turn, where 0 is good, -5 is very over-extruded and +5 is very under-extruded.
Upload the picture for me to have a look at.

(Note: this is exactly what I did to get my bed to within a few microns over the whole surface. Hopefully, it will work for you too...)

Peter

The print was done with the washers.

Ok here is my result

Done without any washers and with your calibration in mind.
Signing off for today - will post again tomorrow.

Phil

Re: Another Bed Unlevel Post (front to back)

OK, so next time, adjust as follows:

Rear -25
Left +10
Right +20
Front +40

See how that goes.

Peter

Re: Another Bed Unlevel Post (front to back)

Hey o/

So I had to redo the first test ... I was to tired (dumb) to put in the right numbers yesterday.
I mixed up plus and minus in the back.
So here are the results:

Test 1

and Test 2 with new corrections.

You can clearly see that something is happening with the corrections.
But the numbers are somewhat subjective - you can't really measure it.

Phil

Re: Another Bed Unlevel Post (front to back)

I think I just found my mistake...
I tried a different approach and this time it seems to work.

Instead of correcting all distances, I just corrected the gap in the middle with some washers.
Turns out that's all you need.

After the gap was gone all I had to do was reset the manual calibration and do some new adjustments.
Still working on it but it's way better than before.

Thank you Peter for your input - now lets see if we can help Lance!

Re: Another Bed Unlevel Post (front to back)

Phil

That's great news. I will leave Lance to you... 😉

Peter

Re: Another Bed Unlevel Post (front to back)

Hey there guys,

Well I worked the fine adjustments again once I got back and have been getting some reliable prints. Seem to be the same level every print. The difference between different parts in the board isn't as noticeable or disruptive so I can manage with that.

Thanks for the help here. I will keep pushing on making tweaks as I go!

Until next time!
-Lance