Help the Newbie?  

Re: Help the Newbie?

Assembled my MK2 a couple days ago, have been struggling to get a decent print out of it ever since. Mostly the issue, which several seem to have, is that I can't get the bed perfectly level so when I live adjust Z one side will be fine and the other side will lift up and after a couple layers the probe will knock the print off.

I've done the calibration, adjusted and re-adjusted ( while measuring with calipers ) the X / Y axis, re-seated the Z-Axis, made sure the bearings under the bed were secure and pushed together and just cannot seem to get the bed perfectly level. The left side is about .65mm higher than the right side in the front and .55mm in the back.

The device is on the felt pads now but prior I made sure it didn't rock at any corner and did this on a flat marble slab just to make sure.

I've run the ( newly downloaded ) version of V2 Calibration and I can get that to print ok, but it's not a very good calibration test as first layer on most prints will screw up because of the axis difference. The "Auto Home" feature is within tolerance given the guide ( a little to the left of center but not touching the edge of inner circle ), XYZ calibration always says "Slightly Skewed" but it is not "alright" as the manual states obviously.

Z Calibration does not come in contact with the bed, I don't have a feeler gauge to test ( wish I did ) but it's probably 2mm (2 sheets of paper) off the bed during Z calibration, maybe a little less.

I've cleaned the bed with isopropyl alcohol and dish soap as well. The only print I got to stick was one where I used the glue stick on and was a large base print ( like 50x50mm ) which from the prusa videos I shouldn't need to do apparently.

I was really hoping the "auto bed leveling" ( which sounds great in theory ) would fix this however I've adjusted the probe in multiple spots and it doesn't seem to make a difference, like the probe is not sensitive enough to compensate in any real helpful way.

Please help me not regret my purchase! I so want to keep this device.

On firmware 3.0.9, tried printing from sd card, slicing with slic3r and using Pronterface as well as Cura and OctoPrint ( just for fun ) but all have the same issue more or less ( not surprisingly since it's an issue with calibration ).

Alright, lets get this printer rocking!

If your Z calibration returns "slightly skewed" your printer probably are, although it doesn't need to be that bad. My printer is abit skewed as well after moving it around a lot, but it prints good anyway.

To me it sounds like your print doesn't stick to the plate, and that's the main reason, not that your build plate isn't 100% level. If you get some heavy warping, that will for sure crash the nozzle or the probe into the model sooner or later, causing it to pop off.

I would like to see a first layer, could you print a 10x10 cm area, just print the first layer, let it print 50% of the second layer, and shut down the print.
Or upload some photos of the V2 Calibration print results.

Re: Help the Newbie?

Hey, thanks for the reply. I have good news, after I posted last night I decided to take one last stab at it. I disassembled the X and Y Axis, grabbed the calipers again, and was meticulous about equal measurements at every step ( took me like 2 hours ). After put together I got a perpendicular result, then proceeded through calibrations. After about an hour of calibrating I'm really happy with how it came out. Adjusting the Pinda probe close as I could get it to not triggering until the nozzle is about 1mm from the bed was a pain ( and I still needed the live z adjustment )

After adjusting the Live Z to -.272mm the V2 calibration pattern looks pretty good. However I saw where it went from a straight extrusion to a more squiggly extrusion after passing the mid point X heading towards the right hand side (+X) on the first 3 passes.

Given this I added the bed level adjustment settings below which has me at just about an even extrusion across the V2 pattern. Had several prints today that when without a hiccup ( clean with detergent then alcohol seems to work well for me every 3 or 4 prints )

Thanks again for the reply, I'm going to play around the next couple days now that I finally can get some decent prints out of this. I still have a lot to learn, I'm pretty sure I'm over flattening the print but this seems to be the only way I can get an almost always good stuck first layer. Don't want to waste anyones time so I'll post again if I run into issues with my settings after experimenting a bit.

Currently Working Settings:

Live Z: -.275mm
Bed Adjust Left: 0
Bed Adjust Right: -20
Bed Adjust Front: 1
Bed Adjust Rear: -11

Re: Help the Newbie?

Hey, thanks for the reply. I have good news, after I posted last night I decided to take one last stab at it. I disassembled the X and Y Axis, grabbed the calipers again, and was meticulous about equal measurements at every step ( took me like 2 hours ). After put together I got a perpendicular result, then proceeded through calibrations. After about an hour of calibrating I'm really happy with how it came out. Adjusting the Pinda probe close as I could get it to not triggering until the nozzle is about 1mm from the bed was a pain ( and I still needed the live z adjustment )

After adjusting the Live Z to -.272mm the V2 calibration pattern looks pretty good. However I saw where it went from a straight extrusion to a more squiggly extrusion after passing the mid point X heading towards the right hand side (+X) on the first 3 passes.

Given this I added the bed level adjustment settings below which has me at just about an even extrusion across the V2 pattern. Had several prints today that when without a hiccup ( clean with detergent then alcohol seems to work well for me every 3 or 4 prints )

Thanks again for the reply, I'm going to play around the next couple days now that I finally can get some decent prints out of this. I still have a lot to learn, I'm pretty sure I'm over flattening the print but this seems to be the only way I can get an almost always good stuck first layer. Don't want to waste anyones time so I'll post again if I run into issues with my settings after experimenting a bit.

Currently Working Settings:

Live Z: -.275mm
Bed Adjust Left: 0
Bed Adjust Right: -20
Bed Adjust Front: 1
Bed Adjust Rear: -11

I've created a Google Prusa MK2 hangout so if you want someone to respond in more real time, you can get that. Granted, someone might not be there 24/7 yet, but I'm hoping this post changes that.

It sounds like you got most of it right. There are a few other measurements that I would like you to double check. These measurements are after months of experience of getting my printer square and adjusted just perfect.

First off, if you got the kit, you probably didn't get a Y-motor brace that you should print. The Y-motor mount should be spaced 67mm from the inside edge of the power supply Y-frame corner piece. This makes it so the Y-motor mount is as close to centered as possible while also allowing the Y-endstop to be triggered. In my experience, the Y-corners should be spaced 151.80mm apart (left to right). This is partly why I created the MK2 alignment sticks.