Still having retraction issues after the change to the e3d-lite and 1.75mm filament. I’ve been keeping track of some parameters, but changing the retraction doesn’t seem to do anything! I kept track of retraction distance, min travel dist, temp, travel speed, and retraction speed. I didn’t want to do lower than 185C because I noticed some breakage due to delamination between layers.
Does anyone know where I should go from here? I’m using an 0.4mm nozzle e3d-lite, with Toybuilder labs natural PLA at the moment.
I also included a photo of the extruder (not bowden) with the cooling fans for reference.
One thing I noticed is the retraction is very fast, and it almost seems like it’s not fully completing the retraction step before the printer moves onto another part of the print. Is that something that’s possible? I’ve had the best results printing with the lowest retraction settings, which seems to be counter intuitive.
200mm/s I think is pretty fast as far as retraction speeds go. I think I usually see somewhere in the ballpark of 60mm/s-150mm/s – which slicer is this? Does it have wipe settings?
Using the newest experimental version of slic3r (the new updates are incredible btw). I have not experimented with wipe settings, but I’m at a loss why everyone can get retraction to work but me…
I’ll try backing off the speed on retract. Maybe it’s skipping steps and I don’t know it.
@Scott_Darrow , I have no idea where you got that silly rule from, because nozzle diameter has very little to do with how much retraction you need. Whoever taught you this silly rule? The need for retraction has much more to do with how closely paired your driving motor is to the nozzle, and many other factors. But nozzle size?..no. Just no.
@Scott_Darrow I’m merely correcting incorrect information. If stuff like that were taken as true, we’d have the craziest of theories and hocus-pocus flying around… Not only that, but evidence almost shows the exact opposite of what you claim. Volcano nozzles with huge orifices actually tend to need a little less retraction because there is less back pressure built up in the hot end cavity.
I will try lowering the retraction speed tonight. I’m excited to have a new direction to try. I was running out of ideas. The 200 mm/s retraction speed was due to a post I found on the internet saying it was ok to turn that value way up to like 400 or 500 (as fast as the stepper would take).
One thing I didn’t realize is that Travel Speed affects the oozing. I actually increased my head temperature for ABS and increased travel speed and my oozing went down significantly.
It’s important to note that the purpose of Retraction is NOT to “suck” filament back up the nozzle. Molten filament in the melt zone does not retract. Rather, the purpose of Retraction is to lower/eliminate the pressure on the molten plastic in the melt zone so that oozing/stringing is reduced.
The reason travel speed affects stringing/oozing, is because without a mechanical way to stop filament from oozing out of the nozzle (like a needle valve, for example), the only way to prevent oozing is to move to the new extrusion position faster than the filament can ooze out of the nozzle.
Layer cooling can also have a dramatic effect on stringing on a part like this pyramid. If not adequately cooled, the filament will want to stick to your nozzle when moving from one island to the next. So some of the stringing shown may not be from filament oozing out of your hot end, but rather from already extruded filament sticking to your nozzle and getting dragged around.
For this specific part, I would recommend finding the lowest extrusion temperature that you can print with, getting as much layer cooling as possible, bumping retraction speed to ~100mm/s (just make sure you’re not skipping steps), and getting travel speed as fast as you can without skipping steps.
Just to close the loop for everyone, I changed my retraction speed to 100 mm/s and upped the travel to 150 mm/s. I’m now running a part and it looks great with no stringing! I’m so excited i didn’t think this was possible. Thank you to everyone in the community for sharing and helping! There is some great info that turned up in this thread.
