Prusa Bed Leveling for Dummies

[great white]

The 100mm test you referenced is about calibrating your extrusion rate.
Basically, you’re making sure when you call for an amount (100 mm is just the test amount) that you are getting what you are calling for.

No more, no less.

You should always calibrate the extruder becuase production tolerances between parts and manufactures vary, which can lead to over/under extrusion.

Obviously, if the extruder is under or over extruding, you will have print problems. Theres a modifier in the firmware that allows you to increase/decrease the extruder in order to get it calibrated properly.

I use a Cr10 v3 with custom marlin firmware. E3d volcano hot end, steel print bed and all in an enclosure for thermal stability. I ditched the print bed springs for solid mounts, installed a bltouch and my firmware has a specific setting to do a custom bed leveling. Works great and re-leveling the bed takes 5 mins if I’m taking my time at it.

It might be a bit of overkill, but I do a new z offset/bed level every time I change a nozzle. The custom firmware makes it a snap. Knock on wood, haven’t had a print fail since I started checking the offset after a nozzle change…

 

[WobblyHand]

I use a Cr10 v3 with custom marlin firmware. E3d volcano hot end, steel print bed and all in an enclosure for thermal stability. I ditched the print bed springs for solid mounts, installed a bltouch and my firmware has a specific setting to do a custom bed leveling. Works great and re-leveling the bed takes 5 mins if I’m taking my time at it.

Speaking only for myself, that sounds like alphabet soup to me. Don't have enough experience under my belt to fully comprehend this, nor can I decide if this is necessary for my needs. There's an awful lot of new jargon to learn. Honestly don't know if learning all of it is worth it to me. I just want to make satisfactory prints for my needs... It would be nice to make nicer prints, but it does seem time intensive.

Actually, I need to make an enclosure. Due to events in the past, probably various chemical exposures, I have become sensitized to the fumes released by printing. Both PLA and PETG bother me. They make my eyes hurt and give me headaches. So I need to both enclose the printer and somehow filter the fumes. It's too darned cold to be opening the windows... From what I hear one uses activated charcoal, but not acid washed, for filtering. Anyways I need to print the parts for the enclosure. From what I understand that will take a week of printing, and a week of high chemical exposure. Or I need to design a metal frame.

 

[great white]

Speaking only for myself, that sounds like alphabet soup to me. Don't have enough experience under my belt to fully comprehend this, nor can I decide if this is necessary for my needs. There's an awful lot of new jargon to learn. Honestly don't know if learning all of it is worth it to me. I just want to make satisfactory prints for my needs... It would be nice to make nicer prints, but it does seem time intensive.

Actually, I need to make an enclosure. Due to events in the past, probably various chemical exposures, I have become sensitized to the fumes released by printing. Both PLA and PETG bother me. They make my eyes hurt and give me headaches. So I need to both enclose the printer and somehow filter the fumes. It's too darned cold to be opening the windows... From what I hear one uses activated charcoal, but not acid washed, for filtering. Anyways I need to print the parts for the enclosure. From what I understand that will take a week of printing, and a week of high chemical exposure. Or I need to design a metal frame.

Stay away from abs then. Very hard to print with and offgasses quite a bit when printing. Much worse than pla of petg…

 

[vtcnc]

I'm just about finished my enclosure. I'll post some pics when I'm done. Was printing hinges tonight for the front doors and am working out a scheme to keep the spool inside the enclosure.

I haven't had any issues with bed leveling on my new Prusa. I find it to be remarkably consistent. Leveled it anew when I put the partially completed enclosure around it and had to relocate the front control panel.

However, I haven't tried to print a full bed of parts either. Just using the middle for now.

 

[WobblyHand]

I'm just about finished my enclosure. I'll post some pics when I'm done. Was printing hinges tonight for the front doors and am working out a scheme to keep the spool inside the enclosure.

I haven't had any issues with bed leveling on my new Prusa. I find it to be remarkably consistent. Leveled it anew when I put the partially completed enclosure around it and had to relocate the front control panel.

However, I haven't tried to print a full bed of parts either. Just using the middle for now.

Parts of my bed are more than flat enough. But the right side corners are drooping or low.

 

[vtcnc]

Can you indicate how much droop you are realizing?

 

[TomKro]

I do like the Prusa, but the rabbit hole for 3D printing is super deep. I'm in the hole, but haven't found the bottom yet.

You're way ahead of me on the Raspberry Pi setup, so I'm sure you'll figure out this new tool.

Not sure where I saw it, but I have seen pics of small vent pipes to carry fumes away from small enclosures. I assume they're using low flow fans. It might be an easier path compared to dealing with charcoal.

As to the bed itself, if you happen to dig into it further, maybe you can compare the top of the hot bed to the bed support itself. If the aluminum support plate is not flat it would only pull the hot bed out of plane when it's tightened. I'm also wondering if there's any "play" in the bed rail mounts. Maybe loosen the right side rod mounts, pull up a little before retightening, and run the calibration again to see if it helps (?).

 

[WobblyHand]

Can you indicate how much droop you are realizing?

I guess it would be possible to measure. Any suggestions on how to physically do this? Attach an indicator to the print head? Then move the head or bed? Doesn't one need to do this when the bed (and head) are hot?

At the high point the filament is too squished. At the droop points the filament is laying on the bed and hardly squished at all. I suppose if I printed a 3 x 3 pattern and measured the thicknesses that would be instructive. Hopefully the corners won't be loose strands.

 

[vtcnc]

If the aluminum support plate is not flat it would only pull the hot bed out of plane when it's tightened. I'm also wondering if there's any "play" in the bed rail mounts. Maybe loosen the right side rod mounts, pull up a little before retightening, and run the calibration again to see if it helps (?).

I think these are good suggestions.

I guess it would be possible to measure. Any suggestions on how to physically do this? Attach an indicator to the print head? Then move the head or bed? Doesn't one need to do this when the bed (and head) are hot?

At the high point the filament is too squished. At the droop points the filament is laying on the bed and hardly squished at all. I suppose if I printed a 3 x 3 pattern and measured the thicknesses that would be instructive. Hopefully the corners won't be loose strands.

I'm not sure you need to measure now that I think about it since you can visibly see a difference in your "squish". If your "squish" is varying that much, I vote for what TomKro is suggesting above. Probably some misalignment somewhere in the assembly.

 

[great white]

A solid bed mount keeps the bed from moving and you can level it once and then forget about it because it won’t move. Made a massive difference on my cr10 as it seemed the bed would “shift” on the spring mounts as it went through its heat/cool cycles.

Adding a sensor like a bltouch will probe the bed surface and the firmware will generate a “mesh” that matches the variance in the bed surface. It then will adjust the z height according to the mesh and the result is even layer thickness, even if the bed is ”off“ a bit.I’ e got my gcode set so it runs a full
bed level before every print, just in case something has moved or warped.