cracking

[DaGroundZero]

Anyone have an idea of why I'm getting these cracks in the print? I'm printing ABS @ 230 C for the hot end and 70 C on the heated bed. I've tried adjusting my prong speeds around, but that didn't help. The room temp was around 69 F. I think I am going to bump up the room temp or get a box around my rostovk to help control the ambient air temp.

Any other suggestions?

Thanks

[geneb]

You might want to bump up the hot end temp a bit. I don't print ABS at anything under 240C. It looks like a simple layer adhesion problem. Note that a draft in the room might cause this as well.

One thing I'd like to try is to get a section of Sonotube that will fit over the whole machine. Cut a door in it and a slot for the extruder mount and it should work well.

g.

[DaGroundZero]

Sounds good. I will bump up the temp and give it another go. Thanks

Also, do I need a fan pointed at my PEEK part if I print at 240? I don't have a fan setup yet

[barnett]

Supposedly this is due to the corners curling as it cools. Assuming you're not actively cooling while it prints. If this is ABS, you might try PLA for less curling. Or as you suggested, heat the room/enclosure. You could also try printing hotter to increase adhesion between layers, but that might cause other quality issues.

[geneb]

As far as I know, the PEEK fan is really only needed with PLA, but I don't think it would cause you an issue with ABS. Someone with more experience should stick their oar in here.

g.

[Polygonhell]

Increase the print temperature somewhat, ABS is a bit of a balance between cold enough to cool quickly and hot enough to bond together effectively.
Air flow on the part can have a negative effect, but IMO you're better off just bumping the nozzle temperature if you have the headroom which in you case you do.
I wouldn't go much higher than 240 with the stock hotend.

[DaGroundZero]

Great information and advise all. This forum is one of the reasons I went with the rostock Max vs another printer. I'll post. Back with my progress.

[RedWood]

This is my experience. 230 had cracking like yours, only less severe. Printing at 225 got rid of the cracks but the bonding between layers was far to week. 235 had the bonding i was looking for but had cracking like yours.
My guess is your layers are cooling and contracting, lifting up on the lower layers.
If you don't need structural strength try turning down the temp.
The only way i was able to have good bonding without the cracking was to build an enclosure and drop in a heat lamp bulb. Im not sure what the chambers temp is because i still need a thermometer. The only metric i can offer is that it's a 125 W bulb.