Test print (logo) & 1st print ok but now prints lifting off bed
Just got the kit, assembled it with no h/w or s/w faults on start-up. did several iterations of Z axis cal until we got a nice smooth, flat rectangle that stuck to bed quite well. Did prusa logo as 1st test - came out flawless. starting printing several small parts for a robot I'm building (2" x 1") 7 all printed without issue. switched to a larger but thinner part (5" x 1/2") 7 other than a slight lift of one corner it came out great. printed it again (i need 2 of them) & this one had slightly more lifting but still usable. switched to another part with is thicker (~1.5") and after the initial 1/8" layer was down the part came off eh bed completely. I'm using the PLA spool which came with printer & all default settings. I clean the bed with 91% Iso alcohol after each print.
What am i doing wrong?
RE: Test print (logo) & 1st print ok but now prints lifting off bed
Always mention whether you are using the smooth sheet or the textured one. Changes answers a bit.
In any case - scrub your build sheet with lots of hot water and an unscented dish detergent like Dawn. Dry with a clean paper towel.
Print right away to finish the drying. No IPA this time.
Do this hot water scrub on a regular basis - maybe monthly.
And of course set your Z correctly. "Live Z my way" is the gold standard.
RE: Test print (logo) & 1st print ok but now prints lifting off bed
sorry ... using the smooth sheet.
I'll clean per your recommendations.
what exactly is the " Live Z my way" ?
RE: Test print (logo) & 1st print ok but now prints lifting off bed
Glad you asked!
That sucker is over 600 pages at this point. Just read the first page or two and print the large calibration surface he provides.
The built-in one is pretty worthless for adjusting Z while printing.
@Bobspro also has a great shorter writeup, but it is off-site. He might link it.
Do your calibration surface, post it here - and we can tell you if you are on the money.
RE: Test print (logo) & 1st print ok but now prints lifting off bed
I've got some notes and pictures here that might be useful.
and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan
RE: Test print (logo) & 1st print ok but now prints lifting off bed
here's the 20mm Live Z Cal I did - it looks good to me?
RE: Test print (logo) & 1st print ok but now prints lifting off bed
@i-am-allin
that looks too high to me, try again, but make the live Z number a bigger negative number,
you can adjust live Z as the print progresses!
the test piece should come off as a single sheet, not a lot of separate spaghetti lines...
if you start to get ripples in the surface, you have gone too far... in this case, dial the live Z back a bit!
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Test print (logo) & 1st print ok but now prints lifting off bed
@joantab: thx for your response .... I can certainly run another test and tweak it but this one did lift off as a single solid sheet and was smooth to the touch on both sides? The pic is greatly enlarged as well ....
This pattern also looked just like the pics from @bobstro’s “notes &pics” link he provided a a few posts ago ... ?
RE: Test print (logo) & 1st print ok but now prints lifting off bed
Also when I ran the test it started printing from upper left to lower right so it was almost impossible to see in real time to make adjustments. Is there a way to start the print from the lower right?
RE: Test print (logo) & 1st print ok but now prints lifting off bed
Just wait until more of it prints. When you can clearly see the pattern, start adjusting. Small steps.
Condition of the first part does not matter. By the time it finishes, you want those last threads to be a sheet.
RE: Test print (logo) & 1st print ok but now prints lifting off bed
Also when I ran the test it started printing from upper left to lower right so it was almost impossible to see in real time to make adjustments. Is there a way to start the print from the lower right?
Unfortunately, you don't have a choice with pre-sliced gcode. However, you can create your own easily enough. Start a new project in PrusaSlicer with a clean bed. Right-click on the print area and select Add Shape->Box. The select the box and click on the little padlock icon on the Scale factors box near the bottom. Set the box to however big you want and 0.2mm high.
After doing that, you can play around with the fill angle to coerce the slicer into starting at different spots. The specific spot will vary depending on layer height and extrusion width, so experiment a bit with it.
I've attached a zip file with a few variants I use:
- The "traditional" 75x75mm square per Jeff Jordan's original post.
- An angled version that starts narrower to the right. I find this quick and easy once I master the process and just need a quick calibration for a nozzle swap.
- A wide and shallow version for the same purpose.
Note that I use the "2 step warmup" procedure, so be prepared to wait for a bit at the start of these prints for the PINDA probe to warm up.
and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan
RE: Test print (logo) & 1st print ok but now prints lifting off bed
Cool thx!. Also, I went back and tugged on my square after my response & indeed the individual strands on the longer sections are not fused. the short ones are so I'm thinking I'm close. Z is currently set at -.650mm so I'm going to change in increments of .005mm to dial it in ... (-.0655, -.0660, etc
RE: Test print (logo) & 1st print ok but now prints lifting off bed
ok, here's another live Z cal .... start was -.800 & end was -.880
I ran an initial one from my original point of -.650 to -.900 and you could see at the end of the print the nozzle was starting to catch so i figured somewhere between -.800 & -.880 was going to be good. what do you all think? Increments were -.020
RE: Test print (logo) & 1st print ok but now prints lifting off bed
It's looking better than before,
Is it starting to feel rough on the top surface at -0.880mm? if so, you are a little too low!
Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Test print (logo) & 1st print ok but now prints lifting off bed
I think it is looking really good!
A good test is when you peel it up. If it comes up as a surface and not individual threads - you are good!
RE: Test print (logo) & 1st print ok but now prints lifting off bed
At -.900 you could definitely feel it was rough. The entire piece (-.800 thru -.880) had all the individual threads fused together when you peeled it off. The sections that were done at -.840, -.860 and -.880 all felt smooth as well. I’m thinking -.860 might be the answer.
another question which arises is dealing with ‘overhang’ sections of a print. The pieces I’m printing have fairly complex shapes and I couldn’t select an orientation where this didn’t occur. Any strategies for dealing with this? When the slicer creates the gcode are there ways to tell it which way to create the layers to avoid theses issues?