Lutzbot TAZ 6 Printer Nozzle Drags back through print

A forum dedicated to the stock LulzBot TAZ 3D Printer
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g2ktcf
Posts: 6
Joined: Tue Dec 04, 2018 9:07 am

Lutzbot TAZ 6 Printer Nozzle Drags back through print

Post by g2ktcf » Tue Dec 04, 2018 9:16 am

I am somewhat new to 3D printing giving that I "inherited' a TAZ 6 from a previous teacher (I teach engineering at our local HS). I have printed several things without fail, then I started seeing the nozzle drag through the material at the start of the print. I have not been able to correct this.
20181204_091126.jpg
You can see where the plastic was just bulldozed aside in the picture. What could be wrong here? This is consistent across the part so leveling should not be involved.

steve0-uk
Posts: 33
Joined: Tue Feb 02, 2016 2:44 pm

Re: Lutzbot TAZ 6 Printer Nozzle Drags back through print

Post by steve0-uk » Wed Dec 05, 2018 1:14 pm

couple of things to look at.

you need to raise the offset a bit, the print is far too squished

what slicer are you using? in Cura there is a z hop and a setting to avoid printed parts with travel movements

start with those and let me know

g2ktcf
Posts: 6
Joined: Tue Dec 04, 2018 9:07 am

Re: Lutzbot TAZ 6 Printer Nozzle Drags back through print

Post by g2ktcf » Thu Dec 06, 2018 12:55 pm

I thought is was far too squished as well and that is what bothered me. Once you get past this initial problem, it prints quite well and clean. I will look at the offset and the hop. It may be a couple of days but I need to get this solved as I have a backlog of printing to do! lol

g2ktcf
Posts: 6
Joined: Tue Dec 04, 2018 9:07 am

Re: Lutzbot TAZ 6 Printer Nozzle Drags back through print

Post by g2ktcf » Thu Dec 06, 2018 2:19 pm

Okay, I have found the Hop settings in Cura. But I have not found the Z offset. Can someone point me in the right direction? That first layer I posted has a literal groove down the middle of the filament. So there is definitely a z-axis issue here.

zachah
Aleph Objects | LulzBot
Posts: 49
Joined: Mon Jul 31, 2017 9:20 am

Re: Lutzbot TAZ 6 Printer Nozzle Drags back through print

Post by zachah » Thu Dec 06, 2018 2:51 pm

You may want to first try manually cleaning off the nozzle. It's likely there is material on the nozzle and that's making the printer think the bed is lower than it actually is.

We recommend using a non conductive scotch brite pad as anything metal that comes in contact with the nozzle risks sending a static shock to the board.

If your first layer is still too high you can adjust the z-offset for you printer. The z-offset is the distance from the top of the leveling washer to the top of the PEI print surface and affects how tall your first layer is.

This can be done through the LCD menu by clicking the LCD knob in once to bring up the main menu then navigating to:

Configuration --> Advanced Settings --> Z-Offset

You can make your first layer less squished by turning the knob clockwise.

Once you have found a good setting for the z-offset, make sure to back up a screen and Store Settings.

The typical z-offset is a number somewhere close to -1.35mm. If you change the z-offset from -1.35 mm to -1.45mm this will make your first layer more squished. If you change the z-offset from -1.35 to -1.25 this will make your first layer less squished.

You can also adjust the Z offset live while the printer is printing. I like to do this while it's printing the skirt. You can do that by selecting Tune --> Z offset while printing.

g2ktcf
Posts: 6
Joined: Tue Dec 04, 2018 9:07 am

Re: Lutzbot TAZ 6 Printer Nozzle Drags back through print

Post by g2ktcf » Fri Dec 07, 2018 8:27 am

Okay, so the first thing I did was to use a dial caliper to measure the top of each washer to the PEI Surface.

Back Left: 1.43mm Back Right: 1.33mm



Front Left: 1.44mm Front Right:1.67mm

The current Z Offset is -1.20mm. The PEI surface is up against the underside of all the washers. However, the right side is soft in the downward direction while the left side is firm. I do know that the surface was replaced last year by another teacher and this could be the issue.

g2ktcf
Posts: 6
Joined: Tue Dec 04, 2018 9:07 am

Re: Lutzbot TAZ 6 Printer Nozzle Drags back through print

Post by g2ktcf » Fri Dec 07, 2018 2:01 pm

-1.13 look like it did the trick. However, my prints still have a small "ridge" where it came off the PEI surface. Is it normal to have to trim off these "edges"?

kcchen_00
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Joined: Thu Feb 19, 2015 12:42 am

Re: Lutzbot TAZ 6 Printer Nozzle Drags back through print

Post by kcchen_00 » Fri Dec 07, 2018 2:21 pm

If the base (side touching the bed) is wider than the rest of the print, it means the nozzle is too close to the bed. Increase the z-offset or adjust the initial layer height settings of the slicing software. One or the other... by increments of .1mm.

g2ktcf
Posts: 6
Joined: Tue Dec 04, 2018 9:07 am

Re: Lutzbot TAZ 6 Printer Nozzle Drags back through print

Post by g2ktcf » Fri Dec 07, 2018 2:29 pm

got it. So I need to go up to -1.12mm on my Z offset.

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