cracks in ABS print

[camden_robot]

I'm getting a lot of cracks in ABS.
Is there any ABS troubleshooting cracks information for Orion that I should refer to ?

[Eaglezsoar]

I'm getting a lot of cracks in ABS.
Is there any ABS troubleshooting cracks information for Orion that I should refer to ?

The layer separation is usually caused by printing at too low of a temperature. You don't mention what
temperature you are using but I would try increasing it 5 to 10 degrees. You should also not be using the
layer fan with ABS. When you slice your STL files make sure cooling is turned off in the slicer software
when you are using ABS.

[camden_robot]

Hi, Thanks for the reply.

I'm using 218 for the first layer and 220 thereafter. And auto-cooling was on.

If I turn off the fan for the entire job and raise the temp to 230 will it not overheat? I'll sure give it a try because the last print was awful!

[Jimustanguitar]

Using a fan on ABS is debatable. Some people do, and some people don't. The best print I've ever done used a fan on ABS, but I've had parts that warp and crack from it too. It's (in my opinion) a case by case thing that you can experiment with and decide upon on your own.

If you're having problems, definitely try it without.

Higher temp increases layer adhesion, so definitely up your temps.

[bubbasnow]

we need to clear something up, do you have a layer fan or just the peek fan?

[Eaglezsoar]

Hi, Thanks for the reply.

I'm using 218 for the first layer and 220 thereafter. And auto-cooling was on.

If I turn off the fan for the entire job and raise the temp to 230 will it not overheat? I'll sure give it a try because the last print was awful!

There are two fans, one is called the peek fan and fits in where the plastic part of the hotend is. That fan should come on when the hotend heats
up and should NEVER be disconnected or turned off. The other fan is called a layer fan and it blows air down onto the part. The layer fan is what
is controlled by the slicer software. PLA requires the fan to be on after the first layer or two and as Jim says ABS does not normally require the fan
to be on but some people will use it with ABS. It has been my experience that ABS does not require the layer fan to be on.
It's a judgement call on your part by experimenting. I wanted to make sure you understand about the Peek fan it must be on or you run the risk
of melting the plastic part of the hotend. The layer fan being on could have been the cause of your layer separation but you can also raise the
temperature to 225 and try that. When you get near 240c you run the risk of melting the plastic on the hotend even with the Peek fan on.

[Jimustanguitar]

I have a PEEK fan that runs above 50c (per the firmware), and I have a layer fan (3 of them actually) mounted to the effector platform that run after the first 2 layers are down.

Some people have bad luck with layer fans, but it did amazing things to improve overhangs, speed up minimum layer times, and made posts and small details "crisper" without melting.

[Eaglezsoar]

I have a PEEK fan that runs above 50c (per the firmware), and I have a layer fan (3 of them actually) mounted to the effector platform that run after the first 2 layers are down.

Some people have bad luck with layer fans, but it did amazing things to improve overhangs, speed up minimum layer times, and made posts and small details "crisper" without melting.

Jim, we know that the layer fans can be useful but for the inexperienced I usually advise to keep them off with ABS. Maybe I should add "until you have a little more experience"

[Jimustanguitar]

Agreed... Don't use one until you know how and why you need it

[camden_robot]

Hello, and thanks for all your replies! I'm glad to say I've printed another part at higher temps (230/110) and there were no cracks. I did get a very flat base where the part was in contact with bed and slic3r had some trouble where there were thin walls (see pics). Here are my settings:

filament: 1.75
extrusion multiplier: 0.9
Auto-cooling: disable
Infill density: 0.6
perimeters (min): 4
layer height: 0.2
first layer: 0.35

perimeters don't touch

infill problem

no cracks!

rounded corner had no support, base is very flat

[bubbasnow]

you might be having an infill issue because your perimter number is so high, you have it set to 4, but on those narrow parts it is trying to do 8 total (4 on each side) so it doesnt draw infill, reduce the number of walls by half and just look at the gcode. it should show you if you are going to generate a infill