Strings galore!

[heathenx]

So S3D crashed and burned on my latest print. For some reason it's all blobby.So I switched over to KISS version 1.5 beta 2.16 and it printed much better, apart from some sparce infill and a shit ton of really fine strings. The strings aren't causing any part functionality problems. It just looks bad. I'm not quite sure what to set my prime/suck/wipe values. I'm printing PLA at 200C. Any tips?

[BenTheRighteous]

This probably falls into the "blind leading the blind" category of advice but to me, 7mm prime/suck seems pretty high for PLA. I would try something between 1 and 3 (maybe 1.5 would be a good starting point?), maybe increase vS a bit and reduce vP. You could also try bringing wipe up into the 8-10 range. Also maybe reduce your trigger - possible that those short jumps are under the 5mm threshold?

[heathenx]

Alright. I had no idea what those settings should be so I took the scientific approach. I guessed.

[mhackney]

Firstly, you should take a look at the KISS manual that a fellow is doing (there is a link on one of the posts here). It will explain what all the settings are and how to use them.

So, here's what I recommend...

1) 200°C is a bit high (depending on your temp calibration, etc) so, do the test to find the minimum extrusion temperature. It is in the "Strategies" guide in my link. Low temp PLA results in less stringing.

2) what hot end are you using? In any case, suck/prime are very high. Lower them to around 2-3mm. They should both be the same.

3) your suck/prime speeds are a bit low - but it is better to err on the low side with PLA. Try vP=45 and vS=25

It really comes down to a suck/prime and temperature optimization to eliminate PLA stringing. That said, I can destroying almost all of my PLAs but I have 1 that still strings a bit no matter what I do.

[heathenx]

Firstly, you should take a look at the KISS manual that a fellow is doing (there is a link on one of the posts here). It will explain what all the settings are and how to use them.

So, here's what I recommend...

1) 200°C is a bit high (depending on your temp calibration, etc) so, do the test to find the minimum extrusion temperature. It is in the "Strategies" guide in my link. Low temp PLA results in less stringing.

2) what hot end are you using? In any case, suck/prime are very high. Lower them to around 2-3mm. They should both be the same.

3) your suck/prime speeds are a bit low - but it is better to err on the low side with PLA. Try vP=45 and vS=25

It really comes down to a suck/prime and temperature optimization to eliminate PLA stringing. That said, I can destroying almost all of my PLAs but I have 1 that still strings a bit no matter what I do.

Wonderful!

1.) My EZStruder usually skips at around 195C but I'll try it there and see what happens.

2.) Using the stock SeeMe hotend with .35mm nozzle.

3.) Roger that!

4.) One more thing that I noticed. My nozzle was set to .35 in KISS. I just changed it to .38 and I'm getting beautiful results at the moment. I'll try your settings above next and post a pic when done.

[mhackney]

On 4) that might mean you were over extruding. Did you measure the actual filament diameter to plug into KISS?

Also, I'm very close to having results with geared steppers on ezStruder. I did enough testing with the CF PLA that I am sure the low steps/mm with 16 microsteps (92.4s/mm) is not providing a) a smooth flow of filament and b) more importantly, reduced torque

Microstepping is good to improve resolution but the downside is it does reduce holding torque.

[heathenx]

On 4) that might mean you were over extruding. Did you measure the actual filament diameter to plug into KISS?

Also, I'm very close to having results with geared steppers on ezStruder. I did enough testing with the CF PLA that I am sure the low steps/mm with 16 microsteps (92.4s/mm) is not providing a) a smooth flow of filament and b) more importantly, reduced torque

Microstepping is good to improve resolution but the downside is it does reduce holding torque.

Yes, I measured the filament. It's 1.73mm and that's what I have plugged in.

This isn't exactly an apples to apples comparison. I tried the mhackney settings BUT I tried to print at 100 micron. I noticed that it was really getting stringy so I stopped the print. I was squirting at 195C.

The next one I did, I moved to 5 prime, 5 suck, 5 wipe, 45vP, 25vS, 2 trigger, .4 z-lift, and 200 micron layers. I ran half the part at 195C and then bumped it down to 190C on the printer. No skips. Reduced strings but they are still there. Obviously, I broke the cardinal rule by adjusting more than one setting at a time. I'm happy with the quality of the print. Not a single blob anywhere. Only the strings.

[mhackney]

Better. Now you can play with seam hiding on the Style page.

Also, because I'm printing precision reel parts, I turn Perimeter speed down on the Printer->Speed tab. I like to print the perimeter no faster than 30mm/s. This also reduces stringing as it gives suck a little more time to do it's thing.

[techstorage]

I found the drop box... Thanks for that post.

I have been using Kiss Pro on my Windows 64 PC. I am unable to find this 1.5 version. At the website download, the link is for 1.4.5.10. I noticed on the screen shot the vP and vS boxes (which are new). Is there a second location where we can get 1.5?

[mhackney]

techstorage, there is a new forum http://www.kisslicertalk.com/viewforum.php?f=6 and a link to the new betas that are in a Dropbox folder on this forum. Those new parameters were done for me! And they are great.

[techstorage]

Thanks, I found it and installed 1.5 beta 2.16.

[techstorage]

heathenx,

Were you able to change settings to remove all stringing? I switched to PLA for a project and have a lot more stringing then with ABS, Angel hair stringing. I could make wigs for my nieces dolls.

[mhackney]

I've been able to completely remove stringing with PLA with KISS. I've printed well over 50 different varieties/colors of PLA. There are 2 that I can't completely remove all stringing but even they aren't too bad.

The key is to extrude at the lowest temperature possible, work on retract and other strategies to reduce stringing.

[heathenx]

I get some terrible prints with KISS sometimes. For every one step forward I take two steps back. It seems to do quite well on some things and just choke on others. My latest gripe is the rounded infill and support material. I used to get outstanding rounded infill and now it looks terrible. As for support, it was too thick and didn't break free from my part. I understand that the secret sauce is in all of those settings. It must be, mhackney, if you're getting satisfactory results.

[BenTheRighteous]

There is at least one type of PLA - eSun orange - that requires a ridiculous temperature to eliminate stringing. I've found that with this stuff, although you CAN print all the way down to 180, you're gonna have a bad time with strings with anything less than 225.

I've heard the "print as cool as possible" advice a lot here, but this makes me wonder how many more materials that's not the right approach for.

[mhackney]

I'm getting SUPERB results, not just satisfactory in PLA. But to be fair, I do NOT use supports with any slicer. If a model needs supports, I design them in explicitly exactly so I have control over them for best removal, etc.

I DO use round infill a LOT (hours of printing a day) and it is always perfect - even on the "0" skin exposed rounded infill. I typically run 25, 33 and 50% round infill. If you were getting outstanding results and now not, something has changed outside the slicer. I've used every version and beta version of KISS for several years and the latest betas produce equally good round infill as the current production version, no difference I can tell.

Some PLAs are more persnickety. These are rare though (at least in my sampling of over 50 brands/colors of PLA). My experience is EXACTLY the opposite, low temperature = less stringing for most PLAs. This is ONLY TRUE for PLA and I am always very clear on that. But in general, using higher temperatures to "fix" other issues is not a good approach. It is much better to determine the root cause and correct that. In almost all cases there are one or several other issues that elevated temperature is just masking.

heathenx, if you can, describe in as much detail as possible what you mean by one step forward and 2 steps back. Honestly, once I got things dialed in with KISS (or Cura or Slic3r) there is very little "surprise" with new prints. I am systematic about making single changes and if I've been printing successfully and all of a sudden have an issue I don't look at slicer config or extrusion temperature first, those are the last things I look to change.

Also, what is your extruder/hotend/nozzle setup? This has A BIG of impact on PLA printing, stringing issues, etc. As much as slicing and if you can't dial in the slicer parameters, then it is likely a mechanical issue. I've found that a short nozzle bore for PLA eliminates a lot of back pressure. Back pressure is a major contributor to oozing and stringing.

By way of example, I am now running a LulzBot KITTAZ Cartesian printer to experiment with and gain experience for my book. I use KISS to slice for it and it is stock at this point with a Wade's extruder and a Budhashnozzle .35mm hot end/nozzle. It uses 3mm filament and is a direct connect extruder. This printer is about as opposite a Rostock Max as you can get! I have taken a systematic approach to dial it in as per my guides and it is dialed in nicely now. But the Budhashnozzle is much more sensitive to PLA stringing issues than my other hot ends. Lowering the PLA extrusion temp a bit and slowing retract and making it a tad longer than I do for metal hot ends has eliminated it except in a few models.

[BenTheRighteous]

Back pressure is a major contributor to oozing and stringing.

Definitely agree on this point.

Also, there is a nozzle called budhashnozzle? For real?

[Nylocke]

Yes, yes there is. I have one, still waiting to build a TAZ to put it on...

[Polygonhell]

They are based on a Hotend called the Arcol Hotend. I have one in a Cartesian printer here, they have extremely low back pressure which lets them print very fast, but tuning out stringing on them is an interesting challenge. They behave very unlike the JHead, and similar designs.

[Nylocke]

I wasn't aware of this hotend or company until just now. Thanks Poly.