Uneven PLA test prints, help!

[artek1988]

Hi Guys,

I am quite new to 3d printing world. I've already print some stuff, but now I am trying to find the best settings, to get a better quality prints. I've printed 7 test cubes, using a bit different set up each time and i managed to reduce the unevenness problem a bit, but i can't eliminate it No. 3 looks the best but still it's not 100% happy about it (note overall shape distortion)
I am wondering if someone can advise me please? Or what is worth trying, because now I am in dead end... Maybe I am doing something wrong ?
Much appreciated for all advise Thanks

Priner: C2C dual extruder 3d priner
Fillament: 1.75mm PLA
Software: Makerbot

All items been printed using Standard quality, 100% infil, 2 shells, 0,20mm layer

1. Ext. temp. 210 C, plate temp. 75 C, ext. speed 90mm/s
2. Ext. temp. 215 C, plate temp. 75 C, ext. speed 80mm/s
3. Ext. temp. 200 C, plate temp. 75 C, ext. speed 80mm/s
4. Ext. temp. 195 C, plate temp. 65 C, ext. speed 80mm/s
5. Ext. temp. 190 C, plate temp. 65 C, ext. speed 80mm/s
6. Ext. temp. 200 C, plate temp. 60 C, ext. speed 75mm/s
7. Ext. temp. 220 C, plate temp. 60 C, ext. speed 85mm/s

. IMG_20150822_181709.jpgIMG_20150822_181746.jpgIMG_20150822_181752.jpg

Thank you very much

Artek

[richardphat]

The pic shows clearly the behaviour of under-extrusion.
Can you actually post a picture of your printer, I just had no idea about this c2c printer.

The cause could be something simple and stupid, also, are these cheap PLA?

[artek1988]

Exactly, under-extrusion.
I had some issues with PLA (black) which arrived with the printer, but some time ago I bought two rolls of better quality fillament (red and blue).
I will change fillamant onto red one and print some test cubes again using same settings as i mentioned in my first post. Maybe colour chemical structure is affecting the quality?

But if you have any idea what else I can do to improve prints quality, please let me know Thanks!

IMG_20150823_123320.jpg

[richardphat]

Color can be a pain when you buy piss poor quality filament, there was this brown PLA from filament.ca, I had to print between 230-240C in order to get best results, not sure why the heck it happened but it did.
Got the brand of the filament?

[artek1988]

I've bought it from ebay: http://www.ebay.co.uk/itm/1816555810...6058f86be&cp=1

I also run two more tests, using red fillament this time... and results are even worse

8. Ext. temp. 200 C, plate temp. 70 C, ext. speed 80mm/s (exactly the same extrusion temp as on "the best" no 3)
9. Ext. temp. 215 C, plate temp. 70 C, ext. speed 95mm/s (maybe i need to do another test reducing speed ?)

I am still very far from getting even close what I expect to get

Photo from side Photo from top

IMG_20150825_211457.jpgIMG_20150825_211516.jpg

[LambdaFF]

.. Have you been printing for long ? Have you alternated ABS/PLA in those nozzles ? Could be you have a partial clog.

[tpete61]

Slow your printer down to 50 or 60mm/s. Start slow until you get a good print and then speed it up.

[LuckyImperial]

Slow your printer down to 50 or 60mm/s. Start slow until you get a good print and then speed it up.

This is what I would recommend as well. It's important to start slow, and then work out bugs as you speed up.

Right now this is my life. I've been fighting all sorts of extrusion/adherence problems with my Kossel printer and I'm only at 20mm/s. If I slow everything down my kossel prints like a champ...it just takes too long.

[richardphat]

Also, have a check on the extruding gear, you never know if your extruder is getting jammed with plastic. That nasty stuff happens frequently. I just cleaned the gear 2 days ago, and the print were much better than now.

[artek1988]

Thanks guys for all your advise

I will do some more prints tomorrow, using very low extrusion speed (20mm/s or 30mm/s)

I didn't made a lot of prints, maybe 15 all togerther, however I had massive clog once , so if slow printing won't give me any positive results I will disassembly whole extruder again and cleen everything up.