Auto_Bed_Leveling: Enhanced G29 command

[DarkAlchemist]

My M5 leadscrews, and nuts, are Stainless 304 Steel. I just don't get how I can have a flat surface but can't get it to tram?

[Roxy]

My M5 leadscrews, and nuts, are Stainless 304 Steel. I just don't get how I can have a flat surface but can't get it to tram?

Actually.... Looking at your numbers again:

+0.08786 +0.07386 +0.06711 +0.10086
--0.05364 --0.01064 +0.03186 +0.11586
--0.17089 --0.07164 +0.00086 +0.12311
--0.26139 --0.13414 --0.03164 +0.13261

It almost looks like your bed is warped. Look at how fast the numbers change on the right side column. They increase .01mm per sample. But on the left side, they are decreasing by .1mm per sample. That doesn't seem right and may be the explanation for your question.

[DarkAlchemist]

Well, how I got these numbers so low is by moving the right side (by twisting the Z motor shaft while holding the left Z motor shaft in place) and this is precisely why I despise the I3 (and variants like mine). 2 motors sharing a single Z is not good and I don't care what anyone says. Alarm bells chime off to all I learned in Engineering about that.

So, I think my first issue is getting the X/Z to be level then work on the bed but what a PITA as I have never been able to get X perfectly level and if I did it will never be exactly the same on both sides due to all sorts of mechanical, and electronic, reasons.

If I ever build a printer the first thing it must have is a non moving bed. It will be firmly in place nailed (lol) down and from there design around that premise.

[Roxy]

Well... My suggestion is start printing... Let's see how the first layer goes down. Your numbers are not horrible for the bed. You want them as good as you can get them... But those numbers are going to work. The difference from one end of a column (or row) to the other is just one layer. The Auto Bed Leveling should split the difference and give you an OK first layer. Or at worst case... You print on a raft.

[DarkAlchemist]

Do those topology numbers represent anything real? If they represented how far off I was from 0 in say mm I could just print a spacer for each leg and maybe that would work or help?

I have been in here playing from the top down since I know these 3mmx30mm screws are level. This is what I managed to just get by going this route and why I said if the numbers meant something I might could print wedges so to speak:

Bed Height Topography:
+0.67194 +0.30644 --0.04081 --0.37506
+0.45494 +0.18369 --0.10131 --0.35781
+0.27344 +0.07619 --0.15981 --0.35331
+0.10144 --0.07331 --0.25081 --0.35581

Look at the right side as I have never seen numbers like that before on this printer.

[Roxy]

Do those topology numbers represent anything real? If they represented how far off I was from 0 in say mm I could just print a spacer for each leg and maybe that would work or help?

I have been in here playing from the top down since I know these 3mmx30mm screws are level. This is what I managed to just get by going this route and why I said if the numbers meant something I might could print wedges so to speak:

Bed Height Topography:
+0.67194 +0.30644 --0.04081 --0.37506
+0.45494 +0.18369 --0.10131 --0.35781
+0.27344 +0.07619 --0.15981 --0.35331
+0.10144 --0.07331 --0.25081 --0.35581

Look at the right side as I have never seen numbers like that before on this printer.

Those right hand column numbers are very good! But the disturbing thing is the left hand does not match it. What it means is your bed is warped.

[DarkAlchemist]

Yep, UPS warped the aluminum frame which also had the Y frame/bed in the middle of it which means it came warped too. I fixed the Z frame being warped with 1/4" beams but nothing I can do with the Y frame. The only thing saving me is the boro glass.

[Roxy]

So is it printing OK? I had an idea. You should be able to change the declared size of your print bed so that the warped area is not used. The warp looks to be entirely in the left most column. You wouldn't probe it (so it doesn't throw off the measurements) and you wouldn't print on it. I bet reducing the size by 35mm to 50mm (In the X Axis????) would cut out most of that warp.

[DarkAlchemist]

It prints fine but I still have a bulge towards the glass and normally that indicates you are printing to close to the glass but I have moved that offset to the point nothing sticks and backed it up until it did and the bulge persists. Not heat related either so I wish I could deactivate ABL and see if that is the cause but can't.

[Roxy]

It prints fine but I still have a bulge towards the glass and normally that indicates you are printing to close to the glass but I have moved that offset to the point nothing sticks and backed it up until it did and the bulge persists. Not heat related either so I wish I could deactivate ABL and see if that is the cause but can't.

Well... You can deactivate ABL very easily. First, you can do a G28 and print without doing a G29. That will set the correction matrix to unity and you will get exactly the same behaviour that you would get if it wasn't turned on. But if you don't trust that, you can simply comment out the line:

#define ENABLE_AUTO_BED_LEVELING

and recompile. It will be GONE ! And you can turn it back on by just changing it back.