Our Taz Pro Dual is acting badly again. I’ve told it to do an auto level, auto measure, and an auto-calibrate multiple times and it still finds a way to dive straight down on the build plate and extrude nothing. I was also printing with ABS on hot-end 2 and after 6 prints the extruder motor no longer spins. Both hot ends were are guilty of never getting the correct, or even, offset.

What is going on here?

All of what you describe can result from dirty nozzles.

The Z offset has to be adjusted depending on your bed type.

If you can post a video of the entire wipe to auto level to attempted print sequence, it would be helpful in narrowing down what needs to be corrected.

I’ll try to get some footage today. Its printing something now but only after I adjusted the nozzle offset to -1.94 after is was found grinding into the filament cause it couldn’t push any out.

-1.94 is trying to put it well below the print surface.

The washers are, by spec, 1.5mm (+/- .05mm):

The typical Z offset for the Pro with the modular glass/PEI surface is around -1.25 to -1.3, which accounts for the washers slightly crushing the PEI layer over the glass. If you’re at -1.94, that’s about a half millimeter into the surface.

If you run the octograb with the spring steel/pei surface, it sits slightly above the washers and the offset would be closer to +0.25mm.

I’ll try that before the next attempt.

I took some video. Seems like I can’t upload it here. Can’t upload it to YouTube either. I’ll try putting up on cloud storage. Image for now.

Even from that one image:

The right extruder’s heatsink fan is on backwards.

This would easily cause heatcreep and jamming of the extruder.

Also, I can guess the following were removed during troubleshooting, but…?

It’s missing the part cooling shroud, so the part cooling fan would be more of a hotend cooling fan, leading to other issues.

The left cable channel is missing.

The right cable channel is missing.

A little minor, but this cable chain anchor is too far over - this:

Should be like this:

As far as the part cooling shroud is concerned Material ALWAYS finds a way to stick to it and cause irreparable damage. Meaning a whole print worth of material will just engulf the entire extruder like it did TWICE in one year (See pictures

included). So they are the first thing to go whenever we had to buy a new head. Putting the cable channels back on proved to be somewhat of a nightmare for one as clumsy as me. So they also remain off. Wish I had 4 arms and hands for that…
After this next print is done I’ll adjust the chain anchor. I didn’t know how far I should’ve put it when I first assembled it. This image helps a lot more. Thanks. I wish I’d noticed the fan was backwards sooner! Dah! No wonder hot-end 2 is messed up now. Looks like I’ll have to do a full teardown this Wednesday. Just for reference this is one of three heads we have due to the myriad of issues that occur from print/part failures.

Material sticking to the shroud is a symptom of another problem. Not a cause. Probably incorrect z offset causing poor bed adhesion. Almost always starts in the first few layers, so being unattended is a major contributing factor.

There’s a few modified part cooling shrouds that allow for better visibility of the printhead.

TAZ Pro Dual Shroud - W shape by RT3DP - Thingiverse

More Clearance v3 - Part 2.stl (407.7 KB)

2mm Shaved Factory Shroud - Part 2.stl (4.0 MB)

These Look WONDERFUL! As soon as I can fix the head I’ll try each of these out. You’re half right about the bed adhesion. The problem that occurred in the images happened after the first 3 layers had been laid down. I walked away, and left it running overnight, thinking everything was alright…as you can see I had no idea what actually caused it since I wasn’t there to witness it. Not until the second time printing something in blue with a different head. That instance I was able to catch it in enough time. But the shroud was destroyed once again.

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I’ll take one for the team and try all three of these out. I am working on getting PrusaSlicer to work with this Taz Pro I resurrected I received from eBay literally in pieces and am not having good results with the default cooling on the dual. The blade one that directs forcefully from one side looks like it would work best, and should make up for lack of two sided cooling by the air curtain.

I designed and used the “Shaved Factory Shroud” with 1.75mm components in the Aero extruders for a while before I changed to the hemera extruders. It worked fine. I can’t remember if I ever used the minimalist “blade” version for anything where part cooling was very important (overhangs, bridging) but for functional parts, it did fine.

I’ve got a good PrusaSlicer profile, but it might need some little tweaks for using the stock toolhead in terms of retraction amounts and offsets, and use of BLTouch instead of the corners… oh, and the custom firmware. There’s a reason I haven’t shared it.

Thanks for the advice!


Since you have the dual working in PrusaSlicer, I wanted to see how you handle the ramp up in temp for the idle extruder. Cura does something clever where halfway through the work of one extruder it issues a ramp up to the other extruder to get it roughly at the printing temp when the first extruder is done. I can’t see to get PrusaSlicer to do this - I had to use custom tool change gcode to do the temp changes (ramp down for idle extruder and wait for the switched to extruder to ramp up). But this adds uncessary delay to the printing process.

Am I missing a PrusaSlicer setting somewhere?

The “2mm Shaved Factory Shroud - Part 2.stl” one was the clear winner. I didn’t start a print with the air blade one as it didn’t seem to be cooling evenly both nozzles. The one I wanted to win was the worst - “Pro Shroud.”

Now, I have a stock 2.85 dual - are you saying the shaved one was actually designed for the shorter 1.75 heatblocks?

To my knowledge, no other slicer does the pre-heating for toolchanges the way that CuraLE does for the Pro Dual. Their code is open-source, so somebody with some programming skills could port it to another slicer. You’d think that it would be beneficial to something like the PrusaXL, so there’d be incentive for them to change… but I think they just expect keeping the nozzles at a close temperature, followed by the prime tower get the job done just as well.

The shaved shroud does clear with the shorter heatsinks from a 1.75mm titan aero. If that doesn’t give enough clearance, you can always pick up some V6 volcano nozzles and grind most of the threads away to get longer nozzles.