Printing with eSun lw-PLA stringing issue

[Jeadcox]

I am trying to print a Radio Controlled airplane using eSun 1.75mm lightweight PLA which is specifically designed for printing airplanes. I’m having trouble eliminating stringing. I’ve printed 38 tests of a partial wing so far and have made good progress. I’ve attached pics of test #2 & #38 for reference. #2 has thick and abundant stringing while #38 has only very thin spider web stringing. In order to assemble the parts, I need to eliminate the stringing.

There are no pre-designed settings for the lightweight PLA so I started with the pre-designed settings for regular eSun 1.75mm PLA. Below are the settings I changed (or changed along the way & changed back) to get the results for print #38. I don’t want to make anymore changes until I get feedback from this group and/or Raise3D support. So…thanks in advance.

- Extruder Retraction Speed = 150.0
- Extruder Retraction Material Amount = 7.0
- Extruder Travel Time = 0.0
- Extruder Minimum Amount Retracted = 0.0
- Ooze = Unchecked
- Nozzle Temperature = 218
- Cooling Fan Control Layer #1 = 100
- Speed Infill Speed = 200
- Infill Pattern = Lines (per the airplane company)
- Solid Fill Bottom/Top = 0/0 (ends are open, not closed)
- Infill flow rate = 100%

[Brian_H.]

Hello my name is Brian. I saw you're post. I'm new here but have gotten (I think) pretty good at 3D printing and specifically with LW PLA. I've used mostly PolyMaker LW which is different than the eSun that you're using in that it is "pre-foamed" or I call it PLA Foam where as the eSun is a Foaming PLA called "active foaming PLA". I'm now using ColorFabb LW which is a Foaming PLA. My current project is an R.C. Glider. I can't say for sure that anything I offer will help much but I can give you a few bits of information from my experience that could help.

Hardware and software for 3D printing have limited ability to eliminate stringing. There are many things that can help (on the hardware side with currently available tech) a short path direct drive extruder could help. On the software side there are many features that can reduce stringing including Coasting. I really enjoy ideaMaker s function of per layer settings. I have drastically reduced stringing in my prints with per layer settings with Fixed Layer Start Point and moving this to different places depending on the layer. If there is geometry that necessitates a travel move I try to minimize the length of the travel. This reduces stringing. You're particular part looks like it would need many separate layer settings and could be a real chore to accomplish but you should look into it. Also it may help to mention the Model and you're Printer. First couple things I see from what you mentioned you're settings look pretty standard however you're print temp seems a little low. I'm printing at 240-250°.

Lower temp is going to produce heavier parts and because the filament is more heavy/dense stringing may be worse with the lower temp at 220. I'm pretty sure eSun prints up to 260°. Also travel moves should have very high acceleration and speed. Think of pulling a table cloth out from under champagne glasses without them tipping. If you know what I'm referencing. If not search for a video of someone doing that. It's the same principal if you can get the nozzle to abruptly leave the filament line (extrusion) that will in theory separate the molten filament strand then moving as quickly as possible to the next location will minimize the oozed filament that is left at the new path.

Another thing to consider is part cooling. It usually can be disabled/off/0 Fan Speed printing LW PLA from my experience. The only place where part cooling is a benefit from what I've seen is with Bridging. You can try these things but be prepared to accept at least a little stringing and you may have to post process you're parts with sanding or trimming. If the stringing is inside the model and you cannot easily remove it but it's not interfering with any fitment or function print the parts assemble the model and fly it. Basically every manufacturing method has issues like stringing with 3-D Printing it is what it is. If you want to know more repost/share my reply with others and ask them if they can explain in more detail what I've suggested.

Take Care