Rough surface and ocasional hole in the print

Hi

I bought a "cheap" (well for someone) 3D printer for prototypes and iam trying to figure out the settings. The documentaton for the printer is really poorly made, the user manual is a joke, so iam seeking help on the internets.

My printer makes the surfaces really rough and bumpy, with ocasional small hole like this: [spoiler]http://i.imgur.com/gKav8u0.jpg[/spoiler] If anyone would have an idea what causes this, it would be apreciated.

Material: ABS
Ex.Temp.: 230°
Surf.Temp.: 70°
Nozzle: 0,5
Layer:0.25 (awailable: 0.08, 0.125 or 0.25)
Fillament 90%honeycomb (or whatever it is called in english)

Check tension on the belt that moves in the axis from rear left of the photo to front right.

YOu mean it might be loose?

- Its either a loose belt or loose hardware. This issue is that your getting an slight axis shift, this also can sometimes be caused by movement backlash if your speeds are too high (but I don't think that's your case ).

that also look typical of overextrusion.

But overflow should be equally evident on all sides.

Ok so either i have loose belt, loose hardware or the printer is putting too much material there.
I tried to check the belt, but i have no tools to measure belt tension, so i only can feel it with my hand, and i dont think i have a loose belt.
About the loose hardware, as i said its a cheap printer. It shakes like an expensive dog when printing, so that might be a case.
As to speed and extrusion, i set everithing according to the User manual wich came with printer.
I have 0.5mm nozzle, printing with ABS.
My settings:
Layer thickness: 0.25
First layer height: 100%
Retract: 400 mm/s
retract Length: 1,5mm (it says 1,5-2mm for ABS)
Lift Z:0,6mm (lifts the extruder head during retract)
Extra lenght on restart:0.2mm (how much extra string is put to extruder after retract)
Minimum travel after retract: 2 mm
Solid Layers:6
Angle of infil:45°
Infil shape: Honeycomb
Infil shape of solid infil:concentric
Randomize starting point: yes

This part i dont understand so i left factory settings there:

primeter Print speed(mm/s or %): 50 (no idea if mm/s or %, i gues its mm/s unles you put the % symbol there)
small perimeters print speed (mm/s or %): 25
Infill(mm/s):60
solid infil(mm/s or %):60
Top solid infill (mm/s or %):50
bridges (mm/s):50
outer perimeter speed (mm/s or %): 20
travell:230mm/s
first layer speed: 50%

I would lower your travel if your printer is "shaking" during print.
The travel-speed is the speed at which your printer moves, when not printing. (so, "in between" print-moves) I see you are printing at 50 & 60mm/s, so maybe lowering this "travel" to 100 mm/s to start with ...

OK ill try. Thanks

Yeah, try travel at 115, see how that looks. If still not very clean, drop everything that is above 50 to 50.

Then keep dropping or increasing as needed, based on how your output looks.

The gaps in the printing may also be due to poor filament quality, either too much moisture or some form of contamination. Poor quality filament results in inconsistent extrusion.

This article on problems with poor quality printer filament may be of some interest.

Ok after some fiddling with temperatures and speed, i got rid of the gaps, but the "bumps" are still there and the surface is still rough. There is actually no change in the roughnes and bumpyness of the surface at all, no matter how i change the settings.



I think ill buy lot of sandpaper. :-)

Can you change your prime/unprime settings? Retract more and advance less between printing and non-printing moves.

Ill try, thank you.

one thing that seesm to have slipped by these guys.

You say it lifts the print head when it retracts.
That's make bumps.
Plus it's totally unnecessary.
Set that to 0.
The less stop and start movement the print head makes the smoother the final print.

So retraction, yes, head lift with retraction, oh hell no !

try that.

And what slicer are you using ?

Slicer? (10chars)

Slicer, the software used to convert a 3D model file into G-code, the computer code used to control the actions of your 3D printer. You can also use it to change settings on your print. see our brief guide to 3D printing software.

I use the software that came with the printer. Its called G3DMaker.