Extruder distance from glass issues ...

[atomholc]

Hi community,

I recently had to trouble shoot a problem with my printer. You can see what happened in the picture below. When the printer was trying to put down the first layer it wouldn't stick to the glass ... because it was too far away from the glass! By continuously experimenting with settings I figured out that I could manually offset the z-axis. I am designer so how I figured this out surprises me ...

I was wondering if I could get your feedback on the following:
1) why did this occur and is it common ... should I expect to offset the z-axis in my code from now on?
2) what I did worked ... but is there another way to fix this without having to offset the z-axis?

Thanks!

[Jules]

Yes, it's an extremely common problem, it's indicative of too large of a gap between the bed and the nozzle (normally from an incorrectly set Z-Stop gap), and you figured out one of the ways around it on your own. Congratulations!

Having the Z-stop set that far away from the glass is going to continue to cause problems for you down the road. You will always need to adjust that Z-Offset. You probably need to re-set your Z-stop. (Not just the Z-Offset.)

We now have a Guide to Getting Started, that discusses this, and pulls together all of the Calibration tricks in one place. In the Troubleshooting section of the guide, it discusses setting the Z-Stop correctly and how to use the Z-Offset to do exactly what you have done here. (Usually not by quite that much though - that's almost a full millimeter gap.)

viewtopic.php?f=8&t=2778

Having said that - I notice that you are printing NinjaFlex. The Flex filaments require very special treatment. I've never printed with them personally. But you will want to read through Insta's Filaments that Work with the M2 thread to find the Ninjaflex entry and make adjustments to how you print it based on the recommendations of someone who has printed it. (For instance, you'll need to drop your printing speeds waaaaaaaaay down, if you haven't already.)

viewtopic.php?f=11&t=1951

It's a lot to read through, but it will make your life a whole lot easier in the long run.

[atomholc]

Hi Jules,

Thanks for the response. I will take a look at the additional documentation and look into how to re-set my Z-stop.

I've been printing with Ninja Flex for a while and have been using the settings that I started in this discussion here:
viewtopic.php?f=11&t=2212&p=11984#p11984

I tried other variations based on recommendations but so far my last settings seem to work the best ...

Best,
A

[Jules]

I've been printing with Ninja Flex for a while and have been using the settings that I started in this discussion here:
viewtopic.php?f=11&t=2212&p=11984#p11984

Never mind the filaments thread then, you obviously know what you're doing with it. But if you are suddenly seeing problems with a filament that you've printed successfully before, your bed might also be getting a little bit out of level. That would be another thing to check.

[PcS]

Personally I used to level bed then set z gap. I knew about the software method but dismissed it as not correct or the lazy way to do it. You should always level bed and set z endstop. Never just one. I change layer heights a lot and like to run first layer at 100 percent so I recently started just using s3d z offset to change it and ...I guess I am lazy because I will never adjust manually my stop again. I don't see any advantage at all other than it taking longer and being hard to access and set.

[innkeeper]

before i made my changes to the machine, i would adjust the gap primarily when leveling the bed... then if i needed any minor re-adjustment id do it while the outline for the first layer was printing by simply adjusting the nob on the z axis for the right gap, allowing me to make last min adjustments on the gap.

typically I would go back and re adjust the bed to match what i had dialed in during printing.

Currently i am running a smoothie board, and an optical be leveling system / z endstop which will automatically compensates for bed unevenness... [ auto trams / auto level ] and automatically sets the right gap. so its completely hands. i've not touched any settings or adjustments in quite a while. Though, if ever necessary i would revert back to cranking on the z knob during that first layer. The z offset is set on the machine with smoothiewear, so i don't have to re-generate gcode because my gap changes.The z offset setting for me is the distance between the senor detection of the surface and the hotend tip's distance minus the gap necessary... therefor its a one time setting. I now never need touch unless i am doing something different where i desire a different gap...

[PcS]

If you set your Z gap to let's say .2 and print at .2 layers and get a calibration cube right on the money with those settings . Then change to a .1 layer the smoothie software changes the offset for a change of layer ? To my way of thinking if it doesn't then you would have to adjust it to maintain it at one to one let's say.

[jsc]

If you look at the gcode put out by any slicer, it always specifies the desired first layer height for the first layer. .20mm layer height starts at .20mm, etc. So in theory, the bed should be touching the nozzle when zeroed. I am still at a loss for why a small gap is generally required to get the proper calibration height.

[PcS]

I have never looked at slicer output. But I generally print at .22. I know if I drop that to .10 the z gap is set for. 2 let's say and I never get good adhesion /squash without changing the z offset the appropriate amount. So at least for me I need to change it.