Nozzle starts digging into print after 3-4mm Z height using ABS
 
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xargxar
(@xargxar)
New Member
Nozzle starts digging into print after 3-4mm Z height using ABS

I´m trying to print an ABS cylinder of 30mm in height, 19mmID and 22mm OD. In the PE slic3r I generated a PLA and an ABS (prusa abs)  version of gcode.

The PLA print comes out fine. The ABS version starts fine but when it gets to 3 or 4 mm of height the nozzle starts digging into print causing it to expand sideways. Its not by a huge amount but enough to ruin the print that comes out looking like a crooked mini vase. 

 

I tried adjusting the Z offset and Z linearity correction but didn´t help.

I'm printing at the deault settings for abs,  255/100 and I´m using a lack enclosure. I have printed ABS boxes and other small parts that came out very well.

 

I would be grateful for any tips or advice.

Posted : 10/07/2019 5:00 pm
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(@)
Illustrious Member
RE: Nozzle starts digging into print after 3-4mm Z height using ABS

Check for the part warping and lifting off the bed.  Very common with PLA and large parts, even more common with ABS, even small parts, when printed outside an enclosure.

I've not printed ABS in bulk, but you also need glustik or abs juice to help hold the ABS to the bed.  So do some searching for articles on improving ABS adhesion.

Posted : 10/07/2019 7:14 pm
xargxar
(@xargxar)
New Member
Topic starter answered:
RE: Nozzle starts digging into print after 3-4mm Z height using ABS

The part is stuck like a barnacle to the steel sheet. Adhesion is excellent.

Posted : 10/07/2019 8:59 pm
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(@)
Illustrious Member
RE: Nozzle starts digging into print after 3-4mm Z height using ABS

If the part isn't lifting, there really isn't a mechanism that will cause the nozzle to dig into the part. Z is controlled by steps, and is geared. Unless the software is telling the printer to go lower (some horrendous error in the slicer), it's down to a mechanical failure at the part.

So either the part if lifting (as shown in this image, and yes, it was still stuck down elsewhere):

Or your heat bed is warping due to the excess heat.   If this is the case, try loosening all of the bed retainer screws, then heating the bed to your preferred print temp, and letting it soak for a while (30 minutes or more), then tighten the screws using the proscribed center out torque down order.  Let things cool and retry the print.  You can also delay printing until the bed has a chance to stabilize by adding delays in gcode. 

Posted : 11/07/2019 12:58 am
Peter M
(@peter-m)
Noble Member
RE: Nozzle starts digging into print after 3-4mm Z height using ABS

Does your z if you move  to the top, hit left and wright at the same time?

Oil everything.

Feel the extruder, up down with your hand, is this loose?

Tighten all bolt screws etc of the printer.

Then do a z calibration(not the first layer),

then do first layer adjustment.

Try printing? try printing with fan on 30, 40 %.

Posted : 11/07/2019 10:35 am
xargxar
(@xargxar)
New Member
Topic starter answered:
RE: Nozzle starts digging into print after 3-4mm Z height using ABS

Thanks for your post will try everything asap.

Posted : 11/07/2019 12:18 pm
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