Nozzle rubbing against just printed part when Y axis moving


I've had great prints from this printer, but tonight i noticed an odd issue.

I'm printing two copies of the same part. One part placed above the other on the Y axis (auto places).

So they take up about 80% of the Y axis volume.

When printing need to move from the top of the Y axis, to the bottom of the Y axis, to move from one part to the next, it sounds like the nozzle is scrabing against the parts.

I can hear the it hit against the ribbs" of the infill, in the wall of the part.

Could it be the beta software that fail to add a Z axis move before moving across newly printed layers?

Or could it be the accelleration that is too high on the Y axis, so the bed is not staying flat and level while it's moving?

I'm using the stock setup for the Cetus, in the Cetus Studio software.

it could be the Z axis itself. Ive had to unscrew all the screws on the z axiz rail use a caliper to make sure the gal is exactly yhe same from top to bottom. after that its completely levelsd and no longer too close on one side. do a nozzle leveling on 4 and 6 to see if they matched in height.

[quote][size=2][color=#999999]BlueDinos post at 2017-1-29 02:38[/color][/size]
it could be the Z axis itself. Ive had to unscrew all the screws on the z axiz rail use a caliper to …[/quote]

I have calibrated the printer now, and there was a very slight difference along the X axis, but nothing significant.

It is still rubbing the nozzle against the freshly printed area.
Thinking about it, I don't think it's related the bed level. The issue appear after a while, so the first layers are layed down already, making the height of the print relative to the nozzle, not to the bed.

The model I'm printing now, is one long model, arranged again along the Y axis, about 95 mm long.

Currently at 9 mm height, and the nozzle is clearly scraping long the top of the newly printed layers when it moves from the top of Y axis to the bottom (X axis is not moving).

It looks to me, as if the slicer need to add a Z move step to add a little (or a little more) clearance when the print head is moved over the model.

I noticed this also but with a pre production Cetus. I was told the new Cetus would be calibrated better in the factory and in Cetus Studio we would get a calibration screen so you can calibrate the X, Y and Z axis. For instance my Cetus does not print straight, all my prints slant a bit to the front. This can be fixed with the software, early Up Plus printers had this issue but not after software calculations.

Check this video to see what I mean:

Sadly I depend on this calibration feature to be added to Cetus Studio to be able to print straight things so I hope to see this soon :-)

@UP_3DWP thanks for the link, and confirmation that I'm not alone with this.

My prints slant about 1 degree towards the front as well. And edges and corners have some strange artifacts.

Here's a little blurry photo (my phone is not that good for macro photos), but the issue is still vissible. 


So two issue reallly, nozzle rub against the part when moving in Y direction (I have not noticed this in the the X direction). And the part is not square on Y axis, but are perfectly square on the X axis.

I have leveled the bed, so as you say, I think it's a more advanced level adjustment that is needed beyond what is currently available to us.

Part of your issue with the head dragging across the part while traveling could be because your part is lifting off the bed due to warping. That will raise the part just enough that the head can touch it as it travels. Worst case is that the head can actually dislodge the part from the bed altogether. The only way to fix that is to move the nozzle down a bit. Do that in calibration.  It will show you the current setting for the nozzle height at the start of a print. I would add 0.05 to that, enter the value then click on Set. You don't have to go back through the entire calibration sequence again. Confirm then try your print again and see if it sticks better. If not then just keep adjusting that by 0.05 each time. If you really think you're close you can even adjust it by just 0.01 or 0.02 to really dial it in. That's the only way to get really fine adjustments to your head height.

[quote][size=2][color=#999999]JanP post at 2017-1-29 18:39[/color][/size]
I have calibrated the printer now, and there was a very slight difference along the X axis, but no …[/quote]

If it's happening on one side or the other only, then it could be the Z axis rail. I live said before mine was off so I had to re-align the z axis rails before it was completely straight. Now I can print from one side to the other with no issues. good luck.

I don't have an issue with the part lifting from the bed. It's sticks quite well to the bed. But yes, that could have been the issue as well.

But it could look like the Z axis is leaning forward a bit. It's hard to get a read on, I don't have a square that has the size that fit under the X axis.

I don't see any obvious places where I can adjust that angle. Can it be adjusted with just the 3 bolts between the bed and the axis?

In future software update, there will be a new calibration function to compensate for skewed print volume which may solve this rubbing issue.

adjusting the Z-axis also help but more troublesome.

 I have a similar issue, when the Y-Axis (axis with extruder attached) moves rapidly, like when making the raft or during some print processes, the Hot End 3D printed plastic shroud catches the printed material and causes a big jump of the Y-Axis arm.

I suspect the arm dips down due to the spike in belt tension due to the inertia of rapidly moving the mass of the extruder.

It has only affected 1 or 2 layers of actual print in 10 hours, but occurs whenever printing the raft creating blobs, which exacerbate the issue.

I think sanding the Hot End 3D printed plastic shroud down will help, which is my first mod I will make.



So I've been on both sides of this issue, rubbing against new printed infill/layers, and not close enough to adhere properly. I seem to have fixed it by just fine tuning the nozzle height. I ended up with something like 181.24 for a sweet spot. Very annoying, but hopefully it's over. At least until I change the nozzle again.

In future, it would be nice if there was a z-hop on retraction function in the Cetus3D slicer to allow the hotend to move without rubbing the previously printed material.

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[quote][size=2][color=#999999]vegasracer post at 2017-2-1 19:44[/color][/size]
In future, it would be nice if there was a z-hop on retraction function in the Cetus3D slicer to all …[/quote]

I second that motion

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Yeah, I too would really like to print some spare Cetus3D parts ahead of time, just in case something breaks (same reason I ordered extra nozzles and build plates). I'm only running the one 3D printer, and I would hate to find out I need a 3d printed part to get it back up and running again.

Thanks! :)

Z hop/Vertical lift would be great, I asked for this also to be added to Up3D/Tiertime 3D printers - my Up Box occasionally knocks structures over.

And I can't wait for the calibration screen to appear in the software, could fix this too as Jason mentioned.

I have had no warping on parts, they are indeed very well adhered to the platform. I did this at the time to make my slightly askew platform level so I did not have to calibrate the height in the software:

I finally had time to re-align the Z axis, It's was well out of square and leaning forward. I took a picture frame, took the glass out, and clamped it to the bed with a bull clip. Then used my trusty (and rusty) old square to align the axis to the bed.

Z AlignmentIssue.jpg

It is now aligned with the bed in both Y and X direction, and the prints now comes out square as well. After recalibrating the printer, I haven't had the print head rub the printed part yet, but I've only printed a small test print so far. Hopefully this fix resolved the issue.

[quote][size=2][color=#999999]JanP post at 2017-2-5 22:28[/color][/size]
I finally had time to re-align the Z axis, It's was well out of square and leaning forward. I to …[/quote]

So after a larger print, the print head is still rubbing against the part.

It only start to happen when the print reaches a certain size. In this case, at 5.6 mm height. The part is 130 * 45 mm in size.

I oriented the part in Y direction, so X is 45 mm wide, and Y is the 130 mm.

It is as if the larger the print, the more mass that are on the build plate, to more likely the issue is to appear. I think the accelleration is too high, without adding a Z clearance step. The single mount point in the middle is not enough to hold the platform level under accelleration when the mass of the print itself is added as well.

Good work, JanP. What did you adjust exactly in order to get your z-axis properly aligned?

[quote][size=2][color=#999999]rdlaner post at 2017-2-6 04:28[/color][/size]
Good work, JanP. What did you adjust exactly in order to get your z-axis properly aligned?[/quote]

I couldn't align it with the bolts that are visible above the build plate, but a little pursuation got the axis in line.

Next test print is running - this one oriented in the X direction, measuring 113 mm (x) and 75 mm (y).

There's a large infill area (at 20% infill) where when the nozzle moves quickly across it, to get from one end of the X axis to the other, you clearly hear the individual ribs of the infill hit the print head.

So it looks like now, that the nozzle will hit the print in either direction, and that the issue is getting progressively worse the taller the print get.

It starts out at about 5 mm, then get worse as it model builds up. At this point, I think about 20 mm tall is the highest I can go without the model either being kicked off the print bed, or the nozzle digging in so far that it starts to loose steps.

Any ideas on how to resolve this?