Fail at 99% of a 27 hour print

[Mike B]

I was printing the top portion of the popular t-rex skull in ABS. I was using .1 layer height and 40% infill so it was quite a long print time, 27 hours or so. At around 94% complete I noticed the skull was not firmly attached to the bed and so I was careful not to walk near or bump the table or printer. A couple hours later when it was almost complete, the skull leaned and fell over.

The heated bed was set to 90 C and I had used hairspray to secured the print. I think a couple of factors could have helped here, for really large prints I might try using ABS juice and I may try to configure some sort of heated build chamber. After the print failed, I looked closely at the object and saw a few cracks in it. I don't know if those came from my kids throwing the skull around after it failed or thermal cracks from the cooling process.. Either way, I was SO impressed with the quality of the print up until the time it failed. The photo doesn't really do it justice (maybe the flash) but the skull and teeth look so smooth and clean with virtually no visible layer lines. I have not done any post work on the object pictured.

Any tips for better results with large ABS print like this?

[Captain Starfish]

Oh damn, I've got tears of frustration just looking at that.

Print a raft?

Abs juice, if you had some made up and a brush nearby, might have let you re-stick the loose bits back to the bed before the whole let go, too.

[Eaglezsoar]

There appears to be little contact between the skull and the bed.
If you had the ability to download the source file and edit it, you could add mouse ears to the rear of the skull to give it more
surface area to stick to the bed. The only other thing that I can think of is to try printing it with support, the goal being to give
more surface area. Printing it with a slightly higher temperature on the filament may reduce the cracking.

[Mike B]

Oh damn, I've got tears of frustration just looking at that.

Print a raft?

Abs juice, if you had some made up and a brush nearby, might have let you re-stick the loose bits back to the bed before the whole let go, too.

Good idea on the raft! I have never used one and wasn't even sure when it would be used.. but this seems to have been one of those times. I have yet to make ABS juice, but I am going to now for sure.Thanks!

[Mike B]

There appears to be little contact between the skull and the bed.
If you had the ability to download the source file and edit it, you could add mouse ears to the rear of the skull to give it more
surface area to stick to the bed. The only other thing that I can think of is to try printing it with support, the goal being to give
more surface area. Printing it with a slightly higher temperature on the filament may reduce the cracking.

For certain, the skull seems to not have much support to keep it from tipping! I agree it needs a larger surface area. For cracking, I had the extrusion temp set to 228 C. Do you think I should go higher than that? I don't know if the cracking is a result of the layers not bonding to each other or if it is a result of the cooling process.

Would a heated chamber help prevent or is that more than is necessary? Thanks for the response. This forum is awesome for newbies like me, thanks to guys sharing their experience!

[Brian]

In Slic3r you need to turn on the "brim" settings and give it a nice fat brim.

The brim it like the brim of a hat. It makes the contact area as big as you want at the bottom layer(s). You trim it off the perimeter when done.

[Eaglezsoar]

There appears to be little contact between the skull and the bed.
If you had the ability to download the source file and edit it, you could add mouse ears to the rear of the skull to give it more
surface area to stick to the bed. The only other thing that I can think of is to try printing it with support, the goal being to give
more surface area. Printing it with a slightly higher temperature on the filament may reduce the cracking.

For certain, the skull seems to not have much support to keep it from tipping! I agree it needs a larger surface area. For cracking, I had the extrusion temp set to 228 C. Do you think I should go higher than that? I don't know if the cracking is a result of the layers not bonding to each other or if it is a result of the cooling process.

Would a heated chamber help prevent or is that more than is necessary? Thanks for the response. This forum is awesome for newbies like me, thanks to guys sharing their experience!

A heated chamber would definitely help. I would not raise the temperature much higher until you verify the reported temperature is actually correct by using a thermocouple meter and verifying
the temperature by sticking the thermocouple wire into the heated hotend down to the nozzle. If the reported temperature is not correct you run the risk of melting the peek on the hotend.
The advice from Brian about the brim is also an excellent idea to help hold the part to the bed.

[nitewatchman]

Mike,

I printed the Skull from natural ABS. I printed at .1mm layer height, 15% honeycomb infill, a tie layer ever 50 layers on my glass plate treated with Fructis Style - Volumizing (For That Full Look) Hairspray with Natural Bamboo Extract. The Hot End was at 235C, the bed at 95C and the print speed at 100mm/s. The Skull was still stuck quite well at the end but could be snapped off easily when the glass plate cooled.

The detail and smoothness is amazing, the finished part looks like it was injected molded. I think it must be the Natural Bamboo Extract in the hair spray.

nitewatchman

[Eaglezsoar]

Mike,

I printed the Skull from natural ABS. I printed at .1mm layer height, 15% honeycomb infill, a tie layer ever 50 layers on my glass plate treated with Fructis Style - Volumizing (For That Full Look) Hairspray with Natural Bamboo Extract. The Hot End was at 235C, the bed at 95C and the print speed at 100mm/s. The Skull was still stuck quite well at the end but could be snapped off easily when the glass plate cooled.

The detail and smoothness is amazing, the finished part looks like it was injected molded. I think it must be the Natural Bamboo Extract in the hair spray.

nitewatchman

Did you take a picture of your finished skull? Excellent job, there have been many reports of failures when printing that part.

[McSlappy]

Yes we demand photos!!

[MDMD]

Are you guys printing with support? I am attempting this print right now at a .25mm layer height. Just sliced it in KISS with support. I'm starting with the lower jaw but plan to re-orient the upper jaw so the teeth are pointed up when I print them.

[nitewatchman]

Yes we demand photos!!

As demanded ------ photos.

This was printed without support. The skull is not water tight and I did not repair it. This results in a couple of thin spots at the top of two bridges but it still prints very cleanly. I did turn on the layer fan when the front teeth started to print, otherwise they are a little rubbery even with ABS. Printed very cleanly just as dropped, back of skull down. I still need to work out on the teeth with a scraper and wire brush.

Guy on thingiverse is working on the rest of the skeleton in the same scale as the skull, he has the legs and pelvis done. If he matches the quality of the Curriculum Model the result will be spectacular. The Smithsonian is also scanning a full T-Rex skeleton and intends to put it on their web site for 3-D printing.

Looking at the finished skull is pretty intimidating when you consider the teeth, muscle anchor points and strength of the jaw. Even an animal this size would be deadly. Now consider the real one was 20+ times larger. If men have been around at that time they would have just been horse-doovers before the meal.

nitewatchman

[Eaglezsoar]

Thanks for the pictures!
That skull looks great! Imagine what it will look like when the rest of the skeleton gets posted. Even at that scale, the whole skeleton will be huge!
Great job in printing the skull and I am jealous!

[barry99705]

Thanks for the pictures!
That skull looks great! Imagine what it will look like when the rest of the skeleton gets posted. Even at that scale, the whole skeleton will be huge!
Great job in printing the skull and I am jealous!

Definitely going to have to print the long bones in parts. Nice thing about using abs is you can just brush on a little acetone and the parts will fuse together!

[MDMD]

Here is my print. The lower jaw was printed with a .25mm layer height with support. The upper was printed with a .2mm layer height with no support. Both turned out amazingly well. Sliced in KISS.

[img]http://i.imgur.com/eyOAuur.jpg[/img]
[img]http://i.imgur.com/PR2nVo4.jpg[/img]

[Eaglezsoar]

Very nice print of the skull.
Thanks for sharing the pictures with us.

[predawnsky]

I was printing the top portion of the popular t-rex skull in ABS. I was using .1 layer height and 40% infill so it was quite a long print time, 27 hours or so. At around 94% complete I noticed the skull was not firmly attached to the bed and so I was careful not to walk near or bump the table or printer. A couple hours later when it was almost complete, the skull leaned and fell over.

The heated bed was set to 90 C and I had used hairspray to secured the print. I think a couple of factors could have helped here, for really large prints I might try using ABS juice and I may try to configure some sort of heated build chamber. After the print failed, I looked closely at the object and saw a few cracks in it. I don't know if those came from my kids throwing the skull around after it failed or thermal cracks from the cooling process.. Either way, I was SO impressed with the quality of the print up until the time it failed. The photo doesn't really do it justice (maybe the flash) but the skull and teeth look so smooth and clean with virtually no visible layer lines. I have not done any post work on the object pictured.

Any tips for better results with large ABS print like this?

that is a smooth looking print

[Jimustanguitar]

treated with Fructis Style - Volumizing (For That Full Look) Hairspray with Natural Bamboo Extract.

Love it!