Sloppy edges on vertical surfaces Prusa I3

I've been having this issue when printing and I appreciate any insight on reducing this stringing. Ive lowered temps down to 184 for the PLA and the external perimeter speeds are at 50%.

The flat parts print out fine (2nd pic) but the vertical surfaces (1st pic) are the issue

Well, if you do torture tests with your printer you have set the retraction perfectly, same for the extrusion by the way.
Try it on a solid object and adjust the retraction until you neither get blobs where a line begins, nor missing bits.

Ok thanks but i'm new to this. When you say torture test I dont understand what you mean. Is there a video or tutorial i can watch that explains the calibration of the retraction and extrusion rate?

Ok, you are new to it, that explains the problem you are facing
This object is not really for the beginner, more for a really well calibrated printer with properly working retraction.
Don't know of any good vidieos to check but there are plenty of calibration pieces available on Thingiverse for example.
You will need good calipers, best the digital kind, to measure your actual movement.
Guides for this are available here in the forum.
If the mechanical part for the axis is fine you check the extrusion with the calipers and from there it is finetuning in the slicer.
Of course if some steppings for a motor are not 100% and you adjust them it is smart to flash a firmware with these settings or to at least store the values in the EEPROM settings.

Thanks Downunder35. I have a good digital mitutoyo caliper I can use, and I will search thingiverse for a "calibration piece"?? I did one before that was a 1"x1"x1" cube and mechanically it printed the correct size.

After that I sort of lost you.

This is the latest print, notice those annoying strings. Found this tutorialI will be trying out in the next couple days

[www.instructables.com]



Thanks

Edited 2 time(s). Last edit at 12/03/2015 05:10PM by Ralphy.

There is plenty that can be used for calibrations, if in doubt just make a cube and cylinder yourself
The print looks clean apart from the strings, which I suppose only happen at the ends of lines.
If your extrusion is otherwise fine increase the retraction by 20% until you see no more plastic is dragged oof the part when the nozzle moves over an empty space.

Well the results for the extrusion calibration are as follows: out of 100mm it leaves 6.38mm left over.

Now I'm trying to figure out the new steps via the calibration formula but my values are set at 0 all over the Marlin Firmware EEPROMsettings in Repetier.

Is this normal? I do remember flashing the board with the Marlin ramps via the Arduino.

How can I calibrate when everyrhing is 0?

Zero just means default.

After you get your calibration done, you can try increasing retraction.

Well I had to unlock the EEPROM in that marlin software and then the numbers showed up. I modified the extrusion rate and it just ended up putting too much plastic down...the nozzle would drag the excess plastic around. I set it back to the old value and increased the retraction from 1mm to 3mm and the speed of retraction from 20 to 50 and the non print moves from 100 to 200. The plastic stringing continues but I notice its that it ozes plastic too soon as it starts printing. It actually ends well the print with no strings but as it does the non print move right before it starts putting plastic again it drips a little. Any idea howto delay the time it takes to put down plastic again?

Here is the illustration notice the stringing starts where the extruder ends the retraction process right before it starts printing again. The beginning of the retraction where the print finishes is getting a clean print.

You did the main things to reduce it: faster travel, retract before travel, more retract. Should not be blobbing. Since yours is, a lot, maybe your retraction is too fast (50 is too fast for mine) and it's slipping and actually no retracting. Try 20 again.

Also try "wipe before retract".

Rruser,

Thanks let me respond to your suggestions. The fast retract isnt slipping I can actually see the pla going back 3mm fast. I can lower it as you suggest just to be sure.

When I received the printer in July it printed nicely with the same pla that i am using now. At the time the pla was new and now its been about 6 months open to the air. I've read pla absorbs moisture and it affects print quality, is that true? By the way my settings were not so aggressive on the retraction it was 1mm retract and 20 for the retraction speed and 100 ms for non print moves.

Another thing they say on other sites that the ambient
temperature and moisture levels affect blobs and stringing some people print one day that has high humidity and get a s loppy print and the next day relatively dry and get a nice clean print.

Lastly my nozzle it sopposed to be .4mm im sure it was that when it was new. Now I measured it and its .56 mm and im puzzled as to why the hole expanded, but that might be causing the dripping right? Close observation indicates it just drips out no matter how low the temp is or how much retraction its set too. I am going to post a pic of a 12 hr print I did in the summer when I was just getting started so you see how clean it would print.

Yesterday I received a new nozzle.

The strigning is virtually recuded by 95% without modifing the settings. I will post pics later on today. In the coming weeks i will expirement with .3mm nozzle and smaller to see if it helps completly eliminate the ooze.

Thanks!

.56 is pretty normal for a .4 nozzle because of the expansion after leaving the tip. If you print a single wall .4 test cube you need to measure the very top row to be accurate. As D.D. mentioned recently, if you measure the extruded filament as it dangles down, gravity will stretch it and give a false measurement. I use Repetier and have only a 1mm retract at 100mm/sec. My "Extrusion Multiplier" is set to .95. Which is 95% of the default flow setting of "1". Between Layer Height, Extrusion Multiplier, Retraction Length and Steps Per MM settings you will eventually cure all these problems. Don't forget that after each setting change you have to reslice. Good luck.