TAZ4: Suddenly has tearing problems UPDATE #2

[Wizard]

Suddenly having a lot of problems with my TAZ 4.

I made this test Pyramid and I think it highlights the issues.
Base 40mm x 40mm and Height 100mm
I added a little cylinder to the front so I could know which way is which. (The bump in the pictures.)
I made the pattern in the bottom to make it easier to remove the bed and see what the top of the rounds would look like. (Boolean Difference cut with a bunch of cylinders.)
The pictures here show the print stopped at about 78mm. (No point in going the full 100.)

Some general settings:
Filament: 3mm ABS Black from Lulzbot
Actual Filament Size: 2.86
Extrusion Multiplier: 96%
Hot End: 230C
Bed: 85C
Layer Height: .22
Slicer: Slic3r 1.2.9
OS: Windows
Perimeters: 3
Infill: Only where needed
Gcode and Model here.
Pyramid and Pipes Difference in Blender with dot on front - COOLING OFF Infill when necessary.gcode (985 KB)
Pyramid and Pipes Difference in Blender with dot on front.stl (247 KB)
ACCEL on TAZ4 LCD: 1100
JERK on TAZ4 LCD: 20  Changed recently up from 8. Was trying to remove the bumps from the corners. Just changed it back to 8 but haven’t printed again yet.

Printer is completely enclosed in a wood and plexi housing.
Also have a small heater in there that I use to initially warm up the box then I turn it off.

Sliced on one machine then moved file to a laptop connected to the TAZ and printed there via Pronterface.

The pictures start with the front and then ROTATE Clockwise around the pyramid. All references to Left and Right are when the Pyramid FRONT is facing you and the front of the TAZ, not in relationship to where they appear in the picture.

Pic 01: Front.
You can see the Front Left edge is bad almost the entire way, EXCEPT where the cylinder bump is directly to the right, then it looks okay for that short bit of height. Also, the cylinder face printed concave and not flat. The Right Edge of the front started okay and then went bad about 2/4 of the way up with lots of tearing on the right face of the pyramid.

Pic 02: Front and Right Side
Lots of tearing at top left, top right and bottom right.

Pic 03: Right and Back side
Lots of tearing at top left, top right, bottom left and bottom right.
Top of the bad is really torn…
On the back, between the tearing on the bottom and top the “edge” of the pyramid looks great on the back right and back left sides. (No bump that is typical of a corner.)

Pic 04: Back and Left side
The most tearing at the top happened here.
On the back, between the tearing on the bottom and top the “edge” of the pyramid looks great on the back right and back left sides. (No bump that is typical of a corner.)

[Wizard]

HERE IS PART 2

Pic 05: Left Side and Front

I’ve been able to print some awesome stuff in the past…

Pic06: The Huntress

Not sure what happened but I suspect something mechanical. I checked the belt pulley’s on the stepper motors and they are screwed on good and tight. There does seem to be a little bit of play left and right on the Build Plate, but not sure what is acceptable.

Any thoughts or suggestions?

[Wizard]

Oh, and here is what the BOTTOM looks like…

[piercet]

Its extruder feed / hotend weirdness most likely. Check the whole path, is the spool able to spin freely, no filliament looped under a strand, is the feed to the tube smooth, are the idler and hobbled bolts still able to move (early taz 4s may not have been sealed bearings) , are both gears intact, no teeth missing, is the small setscrew down and tight, are the Hobbs clean in the hobbled bolt, is the main nut loose enough but still tight enough, and finally is the hot end still heating to full temperature? Also check idler arm tension (start with 8mm between washers on either side of the spring)

In my experience, a sudden drop in quality is likely a gummed bearing or an unhappy hotend.

[Wizard]

UPDATE:

I checked everything in the feed stream and all looks okay. I may need to wipe down the X-Axis rods but other than that it all looks good.

I printed a very good 40x40x40 cube and other than a little tearing on the edges at the start of the print, first 5mm or so, and tearing on the top surface, maybe not enough infill or top layers (3), the sides held really well, no tearing. It looked good.

So then I tried another pyramid (this one a little smaller than the last) and massive failure again…

But as I watched it print the filament looked to stay molten/elastic, and not harden, for a very very long time… Much longer than I recall the last filament did. (This is a new spool I just received and installed.)

So I printed 2x of a new stepped pyramid with the models about 4 inches apart on the build platform. They came out almost perfect (except a little lifting of one corner on the right one, I missed putting some glue there…) I rotated the left one 90 degrees for the build to see if the xy orientation made any difference.

So my conclusion is that something about this new plastic stays molten far longer than usual so anything I build that is narrower than about 15x15mm I’ll need to ensure I’m building 2 of them at once on different sides of the platform to allow each layer time to cool…

I’m also going to run a test with only one pyramid and the fan enabled and see how that turns out. My TAZ is fully enclosed so the fan will be blowing hot air but we’ll see if it helps when printing only one item.

[Wizard]

UPDATE #2

With the fan ON I got layer splitting, which was mostly expected, but none of the tearing I got before.
So, in my mind, this confirms something odd about this new filament… It needs a lot more time to cool between each layer.