Unanswered S3D, Retraction, and Wispy Strings...

Hey guys - recently had to change out the body on my extruder assembly because of a stripped screw. Since I did that, I notice I am getting very light, wispy stringing. They are very light and easily removed, but there. I did not have this problem before I changed out the body. I know the temp should be good because it's the same material I printed before the change with no issue and I have a profile for it.

I did have to recalibrate the e-steps after the install and that is all good now, so I assume it might be the retraction needs to be adjusted slightly. Does that seem right? It is currently at 1.4 now - what do you think would be a good value to try out?

 

Maybe this can help a bit?

https://www.simplify3d.com/support/print-quality-troubleshooting/

 

Thanks. Looked at that before, just wondering what some are using for their retraction settings to see how they relate to what mine are set at.

 

Yeah if it's not a temperature issue, I wonder if the new Greg's wade body introduced some added friction or if the tension screws added anything. However you did an extruder calibration, so I would think that would have accounted for those small changes.

EDIT: I hate autocorrect on my phone.

 

Toro

What if you use something like this http://www.thingiverse.com/thing:66175 and did some temp changes to see if it is a temp thing vs a retraction thing. You also added the two fans and shrouds around the same time. Even though it doesn't look like the shrouds are blowing on the hotend itself, it might have something to do with the change...that is a stretch though.

 

Thanks all. My theory is that it's not the body that is causing me to change settings, it's most likely the filament tension screws. Everything else on that carriage rides on bearings. The screen tensioner, however, would impact both extraction and extrusion. Thoughts?

Sent from my SAMSUNG-SM-G935A using Tapatalk

 

So I am still having this issue. I keep getting wispy strings and zits/rough prints I plan on trying a few things tonight. Some of the things on my list to try are:
1 - Check extrusion. I have already calibrated this twice so I don't believe it's the issue, but I am going to check it.
2 - Adjust min layer time. I have it currently set at 30 sec, but with dual cooling fans I probably need to go lower.
3 - Retraction. I have no idea what to do here. I have read the print quality guide from S3D several times, but I can't frankly tell whether the zit is at the start or the end of the layer. Thoughts here?
4 - Temp. I really don't think this is the issue. I am only printing at 190 and I have had these same symptoms when printing at 188 as well.

Here are some pics. Would definitely appreciate any thoughts you guys might have.

 

Thanks Mark. that was helpful. I'll try that later and see what I get. I guess I'll just try printing single 20mm cubes until I get this fixed.

 

Very good to know Mark, thanks. I was worried that I would be going too low in temp. My understanding is that as long as it is extruding, the temp is good - correct?

 

Thanks - going to try that!

 

Can someone send me the default retraction settings in S3D for PLA? I am going to be doing some troubleshooting and would like to start from a baseline. Thanks!

 

Tried a variety of things but still haven't fixed my zit issue. What I did notice/confirm, is that in the S3D preview, every where they show a retraction, I have a surface defect on my print. It's literally almost a one for one. Any thoughts?

 

Thanks Mark. I did read it - but the answer was still much more guessing than anything else. at least that's how I took it. There were a lot of settings he changed and in the end, he really didn't show any correlation between any change - just that by doing them all, he fixed his problem. The issue I have is that several of the changes he made are somewhat at odds with others he made. So there really is no rhyme or reason, in my opinion.

This is the section I am specifically talking about
"The biggest change from the above post and the current result was
-turned force retract on layer changes ON
-turned only retract over open space OFF
-originally the profile for my printer that had M201 X1500 Y1500 in the start code was changed to M201 X6000 Y6000
-chose one start point instead of optimizing start points for faster printing

Separate from those changes I had these settings for the previous posts print as well as the better print
-0.3 layer height
-coast at end with 0.04 coasting
-extra restart distance -.10
-extrusion width of 0.5 instead of 0.6 as automatically generated for my 0.5 nozzle"

I think I am going to start with the extra restart distance. Starting with -.2 and going from there. I am not sure what the limit is - only that they say you shouldn't go higher than -.5 or so, but again, I think that's a guide.

I am relatively certain that my retractions are causing my problem and I watched them last night as the layers got shorter, it would retract and when it started printing I would get a defect - again, that matched the preview map near perfectly. Given this fact, not sure coasting is going to help.

I am not sure why he says turning "force retract at layer change" on helped. To me, that would be adding more retractions, and since that seems to be causing my issue, not sure I would want to do that.

Thoughts? I appreciate all of your expertise!

 

Thanks for the great writeup Mark. A couple of quick thoughts and questions:
1 - For the extract on layer change, maybe I don't understand that exactly - because I watched mine print last night and although I do not have that checkbox checked, for smaller layers (shorter time), it seemed to retract nearly every time, and when it did, it left a mark. and that appeared to be at the beginning of the layer. So how will checking retracting at each layer help, because in my case it was apparently doing that and it appeared to be leaving a mark.

2 - I think you are right about the temperature issue. I know I am running a little hot because I printed something with a point and it was out of shape at the top. I am sure that's because of heat. The problem is, if I lower the temp, my extrusion rate goes down. My guess is that when I calibrated my extruder, I did it at a higher temp. So I think my first step is to recalibrate my extruder at a lower temp. Most likely 188-190. I had to up it to 205 to extrude the full 100mm, but again, that's likely because I calibrated too high. Since I can't remember what temp I originally calibrated the extruder at, it is probably best to just do it again. Thoughts?

3 - Ironically, in my printing last night I had nearly no stringing at all. In fact in one of my prints I had none. That said, I think I'll have to try it again after I recalibrate the extruder.

Does all of that sound about right?