Repeated Fails T6 dual extruder recently

I teach at a University and we run a couple TAZ6 units for prototypes.
I have one with a dual extruder V3 and in recent weeks it has printed fine. However, last week and again to start this week, I have a student project that repeatedly fails (its striking me now that it could be JUST this one project - I should try something ELSE) - but anyway… As you face the machine the far right hand corner of the bed was like not printing -it was getting squished out bottoming out the print head.

I check Z offset Better but still not good.
Checked Horizontal runout on that arm and turned the Stepper a bit until the run was level.
And I’m wondering if my nozzle is open enough or what - the filament curls on the way out a bit.

Better - but NOW when the machine goes to move from the base layer to the next step - it sounds like its dragging again and eventually fails. I took some pics because you can see the surface finish on the base layer looks like it drags across - its all dull.

Thoughts? Do I need to look at the G Code on this?
I think for sure I need to try SOMETHING ELSE on that same machine and rule out that its not that student’s model.

I open to other input.!


Do you have the original Dual Extruder V3 or the V3.1 upgrade? That was supposed to mitigate the heat creep that was common with the Dual Extruder V3.

On the V3, the shared heatsink had, IMO, poorly engineered cooling flow. The solution that worked for me is https://www.thingiverse.com/thing:3213878 . I was able to get the stock fan to attach with some careful rerouting of the existing wiring. There are also higher CFM 40mm fans that can be used if necessary.

You might also invest in some eSun cleaning filament. Doing some cold pulls with that filament should clear up your filament curling issues.

Thanks. I do have the V3. I haven’t made any changes to it yet -but I appreciate the input there. I was currently running it with the Hot Ends listed as 1. So really only running Extruder 1. I’m in education and unless the part requires the soluble support material, I save it. Its “cheap” on my part, but when I do that, I change the printer to only have one hot end and it does both the part and the support. Its always worked fine for me. Today, after two more failed attempts. I checked the horizontal bars to the bed and adjusted that (again) and then reset Z offsets. When the initial probe goes around and checks for bed level, I watch the Z numbers on the corners. My front left corner (by the wiper) is 12.48, front right corner is 11.86, and my rear right corner is 12.34, and my rear left corner by the plunger is 11.64.
BUT the printer acts like the back right corner is WAY high. She drags the nozzle all across the print and eventually the nozzle quits putting out material because its scraping.

Z for first layer is .4 and for second layer is .68 - but its dragging, You can see it in the attached photo.

Is my bed that far out of level? Do I need to adjust Z in a different way? I’m so frustrated here.

See the drag marks in the rear right corner - its all matte finish where the nozzles rub.

The auto level firmware for the Dual Extruder V3 uses the left nozzle on the left side and the right nozzle on the right side. The assumption is that both nozzles are at the same height.

Check that the assumption is correct by using the LCD console to auto home and then move the nozzle to X=140, Y=140 (the center of the bed or pick a location that allows easy measurement). Now lower Z carefully while using a feeler gauge (or some card stock or paper) on both nozzles until one of them is dragging. Both nozzles should provide the same resistance / measurement.

If the nozzles are not level, check the mount for the tool head. It can be wiggled a little bit side to side when the connecting screw is loosened. The slot is vertically oblong so the foot of the tool head can sometimes not be seated completely and the screw can still be inserted.

I had to lightly file / sand the corners on the bottom of some of my tool heads to insure that they all seated completely.

At this point, if the nozzles are still not level, I believe they can be adjusted (which would probably void the warranty). See https://ohai.lulzbot.com/project/dual-extruder-v3/hot-end-tool-head-assembly/.