Taz 5 print failing, what's wrong???

We are printing a very large print with support. The walls are not very thick. It is a mask that covers the persons whole head. The first time we printed this, it had the same separation, but was a lot worse and didn’t make it as far. This time we changed the print head temperature to extrude hotter (from 250 to 260), but had a similar result.

What is the issue? This mask needs to be printed in one piece (as customer requested). We are printing in ABS and upped the temperature to 260 and print bed at 110.

Turn off the cooling. An enclosure would help also… A blanket or large box over the machine will work on a pinch.

I tried printing a statue nearly at the max. height the TAZ 5 can do, in ABS. I never did get it to not have splits like that.

I went to PLA and it worked OK, with a simple cardboard “breeze shield” around three sides of the printer.

One thing I never tried was to print a full-height “skirt” around the object, five or so mm. away from the widest part, as the part was being printed. That might hold in the heat from the bed and keep the print toasty warm without worry about overheating the stepper motor etc. in the print head.

P.S.: As I recall, more shells helped. I think I ended up using four shells.

I agree with the other posters. It is splitting due to large changes in temperature. Put a box over your printer. When I did this, my splitting problems all but went away. For the few times I had very minor splits, I made ABS slurry and filled the crack and sanded it smooth. Then I vapor polished the entire part.

Thick walls will tend to do this. Thick walls tend to store heat and if the heat is removed quickly, the part will begin to warp. Enough warping stress will cause some of the layers to delaminate.

I’ve also found that thinner layers tend to help prevent this since you get a bit better adhesion between layers. The downside being longer print times.