funny pattern on top layer of prints w ABS only

[dangerweenie]

has anyone had any issues similar to this? you'll see a bit of a "cellular" pattern on the top layer, but only on the right side of the print.

i can't for the life of me figure it out, but it only seems to happen with ABS. i'm happy to share my factoryFile, i thought it would be worth posting a picture in case the issue jumps out at anyone as something obvious.

thanks!

printer: prusa i3 mk2

[wirlybird]

Read up on "pillowing".

Basically more top layers. Not sure why it would only be to one side though. Could be a draft or some other external force acting on it also.

Try rotating the part and see if the issue follows or stays in the same spot.

[arhi]

Not sure why it would only be to one side though.

it's hotter side, the other side either have a slight breeze going over it or bed is bit hotter or the side with too much pillowing is covered from env more so traps heat better ..

[dangerweenie]

Read up on "pillowing".

Basically more top layers. Not sure why it would only be to one side though. Could be a draft or some other external force acting on it also.

Try rotating the part and see if the issue follows or stays in the same spot.

thank you! there's nothing on pillowing in the s3d troubleshooting page but i found some info on other forums.

much obliged.

[dangerweenie]

Not sure why it would only be to one side though.

it's hotter side, the other side either have a slight breeze going over it or bed is bit hotter or the side with too much pillowing is covered from env more so traps heat better ..

thanks very much! i'll need to check the bed temperature on all sides with a laser thermometer.

[arhi]

Not sure why it would only be to one side though.

it's hotter side, the other side either have a slight breeze going over it or bed is bit hotter or the side with too much pillowing is covered from env more so traps heat better ..

thanks very much! i'll need to check the bed temperature on all sides with a laser thermometer.

it's very rare on modern printers that it's up to bed but it's possible (I had 20C difference on one bed I made myself, I was overtrusting the conductivity of aluminium ) ... the way more often the issue with air movement, one side of printer is usually more exposed to "draft" / air movement then other .. that lowers the temp enough to help with pillowing. pillowing is there because you don't have material underneath the print so it sags... adding more top layers "hides" the problem because next top layer have better support underneath it so the issue becomes invisible but it's not really "solved" as the same issue will be visible on other places (bridges, overhangs..) ... turning a "little bit" of part cooling often helps big deal, something like 10% part cooling fan for overhangs, top layers and 20-30% for bridges .. now my experience with ASA is very limited but from what I tried myself it is very similar to ABS... now for e.g. on my "ABS only" printer I don't need to ever use part cooling fan with ABS but for e.g. on other, bigger box, I have to use part cooling in order to get any abs printed, the problem I had was that at 10% speed fan was stalling and at 15% fan was blowing too much air so I had to replace the fan with "worse" one that moves less air so then at ~20% I get perfect ABS prints... problem is with that fan I can't print PLA at all so have to replace fan if I want to print PLA ... I'm now in process of making a different air nozzle so that I can manually physically "block" some of the air so that I can use single strong blower for both ABS, PETG and PLA but few tests I made so far came with ugly results ... anyhow I think that gives you more then enough data how to go about solving the problem.... ( one ugly solution if you can't get reliable low fan speed is to block the air entry to fan with a piece of tape it's super ugly but works )

now you can also print that ASA a bit colder, note that temp readouts on printers are far from accurate, I seen 50C error on many of them!!! so you really want to calibrate your temp!! use a temp tower and print from whatever your current temp 5-6 steps with 3-5C increments and find the coldest print temp that gives you good layer adhesion... colder you print less issues you will have with overhangs, bridges and pillowing.. of course colder you print less interlayer adhesion you have so you need to find sweetspot and that's not what's written on the filament box, that's just a starting point, you need to find that temp for you, for your hotend (other hotend, other hotend sensor.. will have a different value for sweetspot)

hope this helps a bit