PLA Retraction Setting Poll

[area0404 0]

Hi! Just trying to gather the masses' opinion on your retraction setting for PLA on your machine. I've faced some pretty severe stringing issues for a while now. Having dropped temperature low enough to cause delamination between layers (175 for Ultimaker PLA Black), I conducted some testing and realized that low temperature isn't likely to be the solution here. In desperation, I started tuning up my retraction distance and find that may have generated better results.

So far, I find the most effective being 60mm/s and 9mm. Personally, I heard ppl having their optimal result at much lower (like 60mm/s and 5.5mm). Is that something differs from machine to machine? Or perhaps we have yet to discover the optimal setting?

Please answer to this poll so we can find out!

 

[visu-al 2]

How do you setup such a fast retraction speed? My UM2 limits it to 45 mm/s..

 

[area0404 0]

Mine limits to 60 if I do it on my Ultimaker 2 itself. Maybe it is a firmware issue? You can try updating. On Cura however, there is no warning (like when u set your shell thickness to be different from your print head width multiplier or when u put the temperature really high). So I am not sure exactly how high I can go there. I would assume 60 is the limit though.

 

[Daid 306]

The UM2 firmware limits to 45mm. But anything above 25mm/s you risk stripping the PLA instead of retracting it.

Above 45mm/s the motor simply has no power at all to move the filament.

 

[area0404 0]

Interesting. Why does my machine allow me to set 60 though...? Doesn't seem to have problem retracting either. I guess that means it is capped at 45 even though it displays 60?

 

[tinkergnome 927]

...

Why does my machine allow me to set 60 though...? Doesn't seem to have problem retracting either. I guess that means it is capped at 45 even though it displays 60?

 

No, if it displays 60 it is capped at 60 (IMHO).

It seems that "someone" has changed this configuration setting on your printer. It's not very difficult to send a M203 command via pronterface...

 

[gr5 2,229]

When I first got my UM2, 4.5mm was the default and it wasn't far enough. I set it to 5.5 and then I think 6.5mm was perfect. However I also noticed that the bowden tube was moving up and down in the head on every retraction by about 2mm.

The first time I took apart the head - when I put it back together, I seated the bowden tube a little tighter so that it doesn't move on retraction - be careful - if it's too tight it will slowly warp the white teflon part it pushes against (the isolator).

After doing that I found 4.5mm to be perfect amount of retraction.

Another way to test retraction amount is to watch the printer on a print that has TONS of retractions and look at the filament inside the tube at the top of the curve. You can see the filament is at the top of the curve/bowden tube normally and on every retraction it should move just enough to reach the bottom of the tube.

Some brands of PLA don't stick to themselves very well. The print quality isn't as good and you get lots of strings. Every color is different also. Some leak more than others - see first photo here (done on UMO):

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