MK3S+ Layer Shift X & Y axes  

RE: MK3S+ Layer Shift X & Y axes

I think the 'globbing' is the clue.

when printing for a longer time the globs build up and knocks the extruder 

the blobs could be caused by wet filament, over extrusion or a dirty nozzle.

watch a print being made and note if any filament builds up on the nozzle, if working correctly this should not happen.

I am betting your filament is old and became damp - you will need to dry it or buy new filament.

RE: MK3S+ Layer Shift X & Y axes

So, these pictures are inside an enclosure, with a brand new roll of Prusament. 

Bed adhesion is fine. I think globbing may still be part of the problem, and the first one I'd like to fix. 

Thoughts?

If the belts are overtight you risk damage/excessive wear to your bearings.  Make your next print this:

https://www.prusaprinters.org/prints/46639-tension-meter-for-the-gt2-belts-of-i3-mk3s-or-prus

It MUST be printed in Prusament PETG or the spring tension will be wrong.

Bed adhesion is fine.

On the contrary: you have significant warping, enough to cause crashes and consequent layer shifts.

Get the print sheet scrupulously clean and make sure your first layer Z offset calibration is accurate, if you are unsure run the built-in routine and show us the result *on the print sheet*

Add a brim and protect from cold air and drafts while printing.

Grid infill is not a good choice for this sort of print and may be contributing to the globbing, try cubic infill.

If the design permits break the longer print runs in the upper layers to dissipate thermal contraction stresses.

Cheerio,

RE: MK3S+ Layer Shift X & Y axes

Posted by: @diem

If the belts are overtight you risk damage/excessive wear to your bearings.  Make your next print this:

https://www.prusaprinters.org/prints/46639-tension-meter-for-the-gt2-belts-of-i3-mk3s-or-prus

Haven't had time to do this yet, but I'm hopeful. 

I did update the firmware and switch to gyroid infill, and this is today's result:

I'm reasonably sure this is due to blobbing, but that stumps me more. This is brand new filament, in an enclosure, and the nozzle is cleaned immediately before printing. 

How can I stop the blobbing?

The third picture shows you are still warping - fix that and it may fix the blobbing too.

Cheerio,

RE: MK3S+ Layer Shift X & Y axes

The blobbing happened pretty early. I'm on a sparkling clean smooth steel sheet in an enclosure. What else can I do?

r

Brim?

Cheerio,

RE: MK3S+ Layer Shift X & Y axes

Update: Printing with brim. The first layer is nailed to the bed and I still have this blobbing in multiple passes. 

Thoughts?

Thanks.

RE: MK3S+ Layer Shift X & Y axes

Be sure to wipe the nozzle to remove filament globs before the print starts, also under the filament header, there is the 'extrusion multiplier' the value reads '1'  Decrease the value to '0.98'

reprint the first layer. Do not try to printer further until you have a perfect first layer - smooth, even, no blobs or bumps 

RE: MK3S+ Layer Shift X & Y axes

Great advice. So far the current run is going without layer shift, though I confess I've paused a few times to clean up blobs and bumps. I'm going to let it finish to see what final quality looks like and/or give it a chance to fail again.

I've been wondering about the extrusion multiplier as a possible fix. Definitely give that a try on the next one. 

So: blobbing persists after warping is fixed. Please show us your nozzle/hotend assembly from two different angles.

Cheerio,

RE: MK3S+ Layer Shift X & Y axes

Start of print with extrusion multiplier set to 0.98:

Per request, hot end pictures:

I

I've scrubbed with a wire brush to get as much off as I can. 

Just started a full bed first layer test, this is how it started:

RE: MK3S+ Layer Shift X & Y axes

Z Offset calibration:

RE: MK3S+ Layer Shift X & Y axes

The nozzle still does not look clean enough to make good prints. This is a problem with brass nozzles, they conduct heat very well but are prone to have filament sticking. 

You can try cleaning it more but at about 240 degrees. Use a stiff brush but not a metal brush. Be careful of the very small heater wires that a close.

Other choices - 1 - get a new nozzle (changing nozzles is tricky, you need to read how to do it). 2 - Get a more advanced hot end such as the E3D Revo with the ObXidian hot end. This new hot end is more expensive, but filament does not cling to the surface. Also get the 0.6 nozzle - much faster printing as the same resolution

If you decide on the new hot end for the little extra go all the way and get XS model and the Duet3D board!

I have the E3d Revo and with the ObXidian 0.6 nozzle and it solved many old problems.

RE: MK3S+ Layer Shift X & Y axes

Appreciate the advice. That nozzle is pretty new, less than two months on. I've changed them a few a times, and the heater wires once because I wasn't careful.

A hotend upgrade might be worth thinking about...

RE: MK3S+ Layer Shift X & Y axes

So, I had some 0.6 nozzles on hand, so I decided to give that a try. The first print just started, so no results yet. 

BUT, this is the 0.4 nozzle that I replaced. Again, this nozzle has been in service less than two months:

I'm forecasting better results. 

And, I ordered the Revo hotend and the Obxidian nozzle.

You had an imperfect seal between the nozzle and the heat break.  Pay particular attention to the diagrams at the bottom of this page:

  https://help.prusa3d.com/en/article/changing-or-replacing-the-nozzle-mk2-5s-mk3s-mk3s_2069

Two possibilities: Either simple mistightening or your nozzle is not a genuine E3D part; there are a lot of 'clone' nozzles on sale that are about a millimetre too short in the thread...

So your initial issue was a confusing compound of two smaller ones.

Cheerio,