Running auto bed compensation at start of print.
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The reason for the jerky movements is the changes in Z speed due to mesh bed levelling. Increasing allowed Z jerk in the M566 command will get rid of it, if it doesn't cause the Z motor to skip steps.
Thanks David,
That was it, the lowest jerk setting I got it to work at was 1250, up from 900.
I took it up to 1400 with no skipping, but didn't like the feel of the machine at that setting. Less is more.
I had also took the XY steppers up from 1000 to 1100mA thinking that was the problem before that, but have left them there and all feels good.
This is working very well on all materials, and I would recommend others try this in their start script, as it's got to be more accurate than saving a mesh map at one bed temp then using it at a completely different temperature.
I'll leave it all as I have it set up now regarding bed leveling, thanks all for the help.
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I would recommend sending your head to 00 or better a negative position if possible then extruding 15mm of filament at the end of your start script this will make sure that when your print starts it is flowing and has a clean bed
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I would recommend sending your head to 00 or better a negative position if possible then extruding 15mm of filament at the end of your start script this will make sure that when your print starts it is flowing and has a clean bed
I'm not quite sure what that means, but I have my first layer at 150% height and 120% width, so my Z offset of -0.1mm is putting my first layer at 0.2mm with a bit more extrusion stuffed in there.
I'm running 2-4 rounds of brim in the first layer, depending on the size of the printed piece, and am having no problem with the nozzle being primed or bed adhesion at all.
First layers are pretty nice, bordering on beautiful, with a very minor elephants foot and stuck nicely to my printbite surface.
Nozzle zero height is set exactly as per the wiki instructions, and bed is leveled very carefully with a feeler guage.
If you're meaning something else, sorry please explain further, but I'm pretty happy with the result I'm getting here regarding my first layer.
**Sorry, you're meaning to but the nozzle hard onto the bed then extrude some plastic to "pressure it up" before printing?
Only concern I'd have there would be marking the print surface. Contrary to what they say, Printbite can be damaged by a hot nozzle pressing on it.
But sure, please give me an example of the script you'd use to do that and I'll try it.**
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I use a 3mm sheet of polycarbonate (black) so yeah that would harm the surface too. What I meant was sending the print head to a home position like X0 Y0… your start code seems to leave the head in the middle of the bed after homing. On my printer I am able to move the print head beyond the bed into X-14 Y-7 but this is not possible on all setups.
I wouldn't want to build pressure by dragging the nozzle across the surface. What I have found at least is not every print is going to have a successful start if a certain amount of plastic has not been extruded first (this usually shows its ugly head around cold starts or jams).
So in my start code in S3D I do this:
[c]M572 D0 S0.1 ; Pressure advance
M83 ; Set extruder to relative mode
M109 S170 ; Set extruder temp to 170C cold enough to avoid ooze but get some temp on it
M564 S0 ; Can go outside the print area limits
M190 S[bed1_temperature] ; wait for bed temp
G28 ; Home all axes
G29 ; Mesh bed compensation
G1 X-37 Y-7 F12000 ; go to X=-37 Y=-7 (parks head close to home)
M109 S[extruder0_temperature] ; wait for extruder temp
G1 E15 F300 ; Extrude to prime
M564 S1 ; set again the safe area limits[/c] -
P.S. the M564 commands are only needed if you are able to move your print head into a negative position (in other words not over the bed) this command allows you to move beyond the limits you previously setup, if you cant the sending to X0 Y0 would be my next move
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I don't know mate, seems like 6 to one half a dozen to the other.
Mine heats both bed and extruder to full temp before printing, and yes it does go to the center twice…once after initial homing and then again after mesh bed leveling to reset the nozzle height, but I see no real harm in it.
I don't use any pressure advance, do you have a bowden extruder?
I do like how to use 170 degC extruder temp before print start to avoid oozing (which is a pain in the arse), but I want my bed at full temp before probing.
Just goes to show how many options are available for us to use, and I'm thinking some of your script blended with mine might be good for my application.
