New Hexagon hot end

I’ve had my Taz 4 for about 6 months and have been happily printing away. About two months ago I ordered a Hexagon hot end upgrade and converted my old budaschonzle to a flexy struder. No problems there. I did notice on the new hexagon hot end that there seems to be a step in the filament path. It seems like the hole in the printed part and the hole in aluminum plate aren’t quite lined up. I have to rotate the filament to get it past this point. Once I do, all has been fine. Is this normal? I have printed probably in excess of 100 hours on the new hexagon hot end with no problems, until yesterday.
I switched back from the flexy struder and loaded a roll of black ABS, yes I flashed the firmware back to the taz 5 configuration. I ran a three hour print without a problem. I followed that with a 5 hour print, again with no problem. I started a second 5 hour print (different part) and about 3 hours into it it started to air print. I didn’t notice, so it air printed for about 2 hours :frowning: Now I can’t get it to feed. I’ve done several (6) cold pulls with no luck. I heated the hot end to 240 let it cool to 170 and the pulled it out by hand. Any thoughts? Do I have to pull the extruder nozzle and soak it in acetone? Could the step in the extruder filament path be a contributing factor in my problem?

Thanks,

TiM

Hmm… Seems like a clog. Best to keep trying cold pulls…

Make sure the heatsink fan is on all the time. If not, it could be heat creep past the break. This could cause the filament to swells / expands as it liquifies.

As for the “step” in the extruder. It’s possible the aluminum plate shifted side to side. If the idler is too tight, the hobbed bolt will leave teeth marks which could potentially get caught if the hotend is misaligned. The tightness could also be the tighter bend in the filament if close to the end of the spool.

See the assembly of the extruder at the factory in the following video and note the alignment rod they use:
https://youtu.be/f4RGU2jXQiE
It’s the older budaschnozzle, but the idea to use an alignment rod when assembling the extruder should be the same.

Might be a good idea to add lock washers when assembling to keep everything tight… the carriage vibrates a lot.


As a last resort the nozzle can be removed for cleaning. Heat to 165C+. Use two box wrenches one on the heater block (17mm or18mm), and one on the nozzle (7mm or 8mm). THE NOZZLE WILL BE HOT. Plan to grab the nozzle so it doesn’t fall on your print bed (protect the bed / glass from dropping nozzle and heavy tools). Locking vise-grips or locking large forceps work nicely to hold the hot nozzle. Soak the nozzle overnight in acetone, use a pick to remove debris and floss the opening with a strand of wire. Take your time re-threading, the heater block needs to be at 165C+, finger thread to make sure you don’t cross-thread the soft brass… BE CAREFUL THE NOZZLE WILL GET HOT FROM THE HEATER BLOCK. You get 10-20secs to thread before its too hot to touch… Let it cool down and try again. Once threaded use the wrenches again. Once tightened, heat the hotend to 250-290C and tighten one last time. The brass is soft so don’t crank on the wrenches :slight_smile:

Hope this helps! Good luck!

I’ve got it back up and running again. It’s amazing what some time in acetone and an ultrasonic cleaner can do. While I was noodling around I noticed something on the recommended Cura settings. They are recommending 10 degrees higher for ABS on the TAZ5 (240 instead of 230) and 205 verses 180 for PLA. I’m assuming since I have upgraded to the Hexagon hot end I need to use the higher temperatures. I may have been extruding at too low a temperature which let to my first clog. I also noticed they are recommending a bed temp of 110 for ABS on the 5 instead of 85 for the 4. Is this due to the different bed coating?

Thanks,

TiM

One of the reasons I upgraded to a hexagon hotend was so I could print ABS at 250c. I have had a love / hate relationship with ABS from the start, a lot of my printing needs to be structurally strong and ABS always had a weak spot, layer adhesion. Parts printed vertically could snap at the layer seems with modest pressure and it’s not always feasible to print them horizontally.

So I upgraded to the Hexagon hotend and started printing ABS at 250c and did some (non too scientific) failure testing and there was a significant difference in strength from 240c prints. I now print all my ABS at 250c.

Yes, the bed temps are for the PEI bed. ABS sticks great at 90-110C. And the hex does require slightly higher temps… For eSUN ABS my sweet spot is 240-245C.

Agree also that higher extrusion temps help overall layer adhesion… The strongest parts seem to be from the .5 nozzle with a .3 layer height. Detail was good, and the parts were stronger than with the .35 nozzle.