Bad stringing - retraction settings?

[drumrboy44 0]

Hi all,

I have some questions about some very bad stringing that I've been getting. Currently, I am using the Cura 13.04 default retraction settings: [Min travel = 5.0mm, Speed = 40 mm/s, Distance 4.5 mm, extra length on start 0.0], but I still get what I think is bad stringing on most of my prints, seemingly regardless of print speed. I have been printing at between 35-80 mm/s, and mostly around 210 C. Attached is a prime example of the stringing I get, which makes little sense to me, since the stringing is clearly beyond the minimum travel distance set for retraction in

Does anyone have any ideas? Could this be caused by some other setting, or something mechanical?? Thanks in advance.

-Drumrboy44

 

[illuminarti 18]

Does the retraction appear to happen? Do you see the gear wheel turn backwards when those moves are being made? Did you remember to enable retraction on the first tab of Cura?

Secondly, what firmware are you using? Is it one that came with Cura, or something newer you built yourself?

[colorfabb 3]

You could also try increasing the travelspeed to about 200 mm/s or even 250mm/s. This is a nice model for calibrating the retraction settings: http://www.thingiverse.com/thing:11846

 

[Daid 306]

You can dial down the temperature even more, some people go all the way down to 190C to get as little strings as possible. Increasing the travel-speed also helps but might cause layers-shifts if your machine isn't running very smooth.

 

[drumrboy44 0]

Interesting... Well upon checking again, the retraction was not actually happening, despite the tab being checked on the first Cura tab. I reinstalled Cura, re-installed the Marlin firmware that came with it, and now the retraction at least is happening. I will see if this solves my stringing issues. Would anyone make any changes in the default settings for retraction as I listed them in Cura?

Thanks all!

 

[gr5 2,170]

First of all see this image that demonstrates the relationship between stringing and temperature:

http://umforum.ultimaker.com/index.php?/topic/1872-some-calibration-photographs/

Note that different brands and colors of PLA flow (have different viscosity) at different temps so 190C might not be for you.

Also answering your question - I only mess with the distance parameter. I change that on every print. For your print I would set it to maybe 10mm as that is the big gap that you want retraction on.