Suddenly more and more Warts/Zits (alot) on print surface. (ABS)

Hi,

Ive been printing for a while now and about 10+ objects have come out fine.

Recently however my print surface has gotten worse and worse. Showing warts and zits.
As can be seen in the left model in the attached image. (The right print is one I did a week back that was still ok)
The last picture is also one of a print gone right.
I do not hear popping that would indicate moist filament.

Printer: Leapfrog Creatr dual extruder
Material: ABS
Temp: 225 to 235 all show this problem.
Bed: 80C
Slicing software: Simplify 3d

My own idea: Z height increments are too low.

Any Ideas?


P.S.:
Seems to be the same problem but no answer: [forums.reprap.org]

Edited 2 time(s). Last edit at 03/04/2014 09:04AM by Crewmember.

Is it stinky? The extruder might be running hot, which causes something like a phase transition in ABS. It smells bad, gets a glossy surface, and can make bubbles. Probably the stink trying to get out.

Ill check that today.

You have moisture in your filament. Does it make small "puff's" when printing?

Quote
Kenzu
You have moisture in your filament. Does it make small "puff's" when printing?

Nope, Like I said in the OP I hear nothing like that.

How easy is it to get moisture in ABS filament? Its in a dry room, but Ive never put it in a plastic bag or anything. its always just laying in the machine.

I never had the moisture problem my self or a problem that looks like yours. If it's not moisture, it could be your feedwheel/hobbed bolt that are slipping/stripping the filament. Try to lower the printspeed.
It could also be bad filament. Cheap black filament is often made from filament waste from other colors and black color pigment. So it could be bad or maybe the tolerance is slipping, so the diameter sometimes get a little the big for your extruder/hotend.
With that said, try some other filament if printspeed does not solve it.

So ive decided to tell the software to switch around what extruder prints what. And the surface quality is still bad.

However the supports printed by the previously bad black extruder is now looking ok ish.

I also noticed that the bad surface seems to me most noticable on the top of the product when there is a rib underneath the surface. (pic 3) Can someone make any sense of this?

It looks to me like you have a mechanical extruder issue there somewhere that is causing extrusion buildup in some areas, and slight voids in others.. What type of extruder are you presently using? If it is a Wades style, check that the idler bearing still works (they can gum up sometimes), and that the set screw on the small gear is down and tight. Also check that the hobbed bolt is not too tight or loose, and that those other two bearings are fine. Remove any filliament shavings from the idler chamber, clean the hobs with some sort of pointy object, then reassemble and readjust tension. If you have a plate mount style hotend (Buddaschnozzle, etc) also make sure that the filliament hole is still lined up properly. After that is done, run a filament calibration and make sure that the extruder is dialed in.

Also try using the newer slicer 1.0 variants if you are still using .9 as that reduces excess extrusion on circles and radius

Thank you for the answer piercet.

Im using what I guess is a wades style extruder without the sprockets.

For now I recalibrated the bed and that actually seemed to fix it. Stil dont know how that would cause these problems but o well.

I havnt tried the same file yet (just a simmilar file) so im still not 100% sure. I will check next week. (This printer is at my workplace)

Im using simplify 3d not slic3r btw

You have a hobbed pulley style microextruder. I'm guessing something along the lines of a Makerbot Extruder MK. 7, but I don't recognize the actual model from the picture. The operation theory is similar. For example the red residue on the hobbed pulley itself is impacted plastic. You ideally want to clean that out when you get a chance, which should improve your print quality by ensuring the correct amount of filliament is fed through.

The bed leveling is important because the thickness of that initial layer determines how much excess or lack of plastic the extruder has to make up in later layers. if it's too thin (overall or just on one corner or side), you will tend to have excess filliament blobs on later layers. Too thick tends to be less of a problem (aside from the part not sticking to the bed) because the extruder only extrudes so much plastic per a given length of extrusion anyways.

Glad you got it working!
TIm