The Splits

[gestalt73]

I think I may need to raise the bed temp by 10c, lower the extruder temp by 10c, and leave the print cooling fan off.

What do you think?

bed temp: 70c
extruder temp: 250c first layer, then 240c
printed on glass bed with elmers glue stick
using a hefty(tm) or glad(tm) enclosure
first layer corners spackled with abs slurry
0.50mm nozzle
printing 2 perimeters, skin thickness 0.45mm, 33% infill
0.15mm layer height @ 40mm/s
40mm print cooling fan @ 40%

I've just begun doing long overnight prints, I seem to be missing something.

The other two objects look good, but I won't know for sure until the print is done in 3 hours.


[img]http://i.imgur.com/iACaVoC.jpg[/img]

[Eaglezsoar]

What kind of filament is this? You are printing at 250 first layer with a stock hotend?

[gestalt73]

It's ABS, with the stock hot end. Just the first layer.

I've been trying different things trying to get these prints to stick.

[bvandiepenbos]

ABS right?
Raising the bed temp won't make much difference.
I would not lower extruder temp, you want enough heat for good layer bonding. Have you checked your hot end temp with a good meter with a thermocouple probe close to nozzle? ...just to be sure the LCD is reading true temp.
If it is really 240c then that should be fine for ABS.
Definitely try without print cooling fan, It can cause larger prints to split like that.

ABS is about impossible to not get warps and cracks.

PLA does not warp nearly so much.

[bvandiepenbos]

Hairspray on glass works great for me.
Aquanet super hold unscented. Walgreens or a Dollar Tree store, sometimes Walmart.

[Eaglezsoar]

I agree with Brian about the cooling fan, it is not usually necessary with ABS.
You temperatures worry me, the peek in your hotend starts to deteriorate and melt at 240+
I run ABS at 230 and use a shot of hairspray on the bed to help ABS to stick to the plate.
At 250 first layer and 240 for the rest of the print you are running a very high risk of destroying your hotend, if
you want to run at those temps invest in a E3D or other all metal hot end.

In summary, try to turn the temp down to 230 or so, turn off the cooling fan and see if you notice an improvement.
PLA benefits from a parts cooling fan, ABS not so much. DO NOT TURN OFF THE PEEK FAN!
It is inevitable that ABS likes to curl and crack and it can be an art to prevent it, especially on the large parts. Each
of us use settings that are best for us, but please be careful with temps at or over 240 unless you get the all metal hotend.

[gestalt73]

OK, thanks for all the pointers, I'll try it next with lower extruder temps, no cooling fan, and raising the bed temp a bit to keep the temp differential down.
Obviously I have to reprint at least one of those pieces. :-/

I was printing for a while on blue painter's tape + aquanet, and switched to elmer's glue stick on glass when I was getting curling, so far the elmer's seems to work better.

I've done a couple of runs with a full bed of parts since I switched to elmers, more or less successfully, and this was the worst fail so far.

Now that there's a US distributor for the E3D, it's next on my list.

Hopefully I'll be able to post back to this thread with a good part after making those changes.

Thanks!

[gestalt73]

Success!

So, I changed a couple of settings:
- extruder temp to 240c for the first layer, then 230c
- raised bed temp to 80c
- used abs slurry thinned out before the first layer

For most prints, elmer's glue sticks do the trick really well. This particular print was very thin and very tall, so for these types of prints I'll use the abs slurry.

Thanks everyone for your help!

[img]http://i.imgur.com/eqaWatS.jpg[/img]

[Eaglezsoar]

Looks good! I'm glad you found the right settings.

[bvandiepenbos]

glad to see you got a good print.

Did you turn off the part cooling fan also?

[gestalt73]

Yep, part cooling fan stays off now.

I'll save it for the small, delicate parts. the big parts go without the fan now.

Thanks for your help!