Prusa I3 bad printing

[Cappy_Soda]

Hi guys, don’t know if this is right place to post this, but here it goes:
I’m using Prusa I3, and I’m kid of new to 3D printing. I use to get ok-good prints on the start, but not any more. I use Cura, and this settings (pic bellow). So I realy don’t have any idea what to do more. I try to calibrate it as much accurate as possible and tried different settings. Any advice or solution for this problem? (model pics bellow)
Layer hights 0.1-0.2
Printing temp 185-195
shell 0.8-1.2
Thanks!
p.s. I’m using chinese filament which I get with printer.I know that is a problem but not as big as my prints are bad. And I did get some good prints on the start.

[Stanos]

Is your filament actually 1.75? Have you checked it with digital calipers? It looks like over extrusion. Plus you are trying to print at .1 which amplifies the problem of over extrusion. If the diameter is closer to 1.8 then the machine is pushing more plastic than it should and causes what you are seeing. Try upping the diameter or lowering the flow rate.

[RCole]

It also looks like the prints I had when my filament was “wet” (lots of bubbles formed). You might want to dry your filament in an oven.

[Cappy_Soda]

It’s not wet, but maybe it was humid before

[Cappy_Soda]

yes it is 1.75. I dont have right now digital caliper unfortunately. I try to print .1 and .2, and same results. bad print.
It is posible that diameter is closer to 1.8, it’s cheap filament. Prints on pictures are on .2.
I will try to lower flow rate and upping the diameter. thanks

[Cappy_Soda]

One more thing, nozzle looks like it’s pushing the object down. like it’s wedged to plastic.

[RCole]

That is what I meant by “wet”. I live in a very humid place. Once the filament absorbs enough moisture, I have to bake it for a bit. I’ve gotten much more desiccant now that I store the filament in. No more bubbling problem.

[Cappy_Soda]

Thanks RCole!

[Cappy_Soda]

Do you think that was problem in this model too?

[fjohannes]

the guesses so far are good

1. humidity!!!

2. over extrusion because of bad tolerance of filament diameter - you NEED a digital caliper because the 0.05mm difference between 1.75mm nominal and 1.80mm actual doesn’t sound much but actually is 6% more material!!

3. The guess I would add is the quite low temperature. the pictures look, as if it could be that the plastic is too viscous to melt throughout and lay down nicely. I am printing my PLA at 210degC

[RCole]

I’m not sure on that one. It looks more like what I got when I tried to run the Taz 5 at high speed. Every layer was shifted a little bit in one direction or another. Very rough. Can’t say for sure, though. What speed are you printing at?

[Cappy_Soda]

printing speed was 50 mm/s I think. But lately I was printing 20-30 mm/s. On monday I will try with new filament, hoping for much better results

[Cappy_Soda]

Yes, humudity for sure. I had my doubts about that, but it is now for sure. I dont have digital caliper right now, but on monday I’m buying new filament. Hope for a better results. Thanks fjohannes.
p.s. I’m printing cca. 195degC, and bed 65degC

[jfield]

Is your filament really from 2014? That’s really old! PLA picks up moisture, so that could start out printing ok, but if it is not sealed up good, it will absorb moisture. And what happens to water at 100C and above? It turns to steam! Hence the bubbling in your print.

[Cappy_Soda]

Hi, i bought a new filament, black 1.75mm Devil design. That fixed bubbles, but now I have problem with over extrusion. How can I fix that?

[Cappy_Soda]

This is model printing right now

[Miro]

Before anything you really have to calibrate E steps,only then you can start troubleshooting. Triffid_Hunter calibration guide is very good.