And finally the last Part …
In Part 2 we looked at the most important settings for printing with LW-PLA - Nozzle Temp, Flow Ratio, and Speed (aka Max Volumetric Speed). That got me to a really good looking test print. But I started noticing some flaws …
Even though the Eclipson files minimize seams, the seams that remained were really visible and were creating “loops” in the filament. When the seams were on the outside of the print (if I set the Seam Position to “Back”) it created a very visible ridge of filament extrusion. If I moved the seams inside the print (using “Nearest” or “Aligned”), the seams would sometimes print the extra material in critical mechanical areas. If you look closely at the Slicer output, you can see that seams force a retraction and Z Hop (the default Z Hop Type is “Spiral” which creates the loops). And LW-PLA hates retractions and Z Hops! So I went into the Filament Settings > Setting Overrides and set Retraction Length to 0 to disable it (which also disables Z Hop When Retracting). Or you can try minimal Retraction Length (0.5mm) and no Z Hop When Retracting - honestly I didn’t notice a difference. No more messy extra extrusion at seams! I still recommend trying different Seam Position settings on your models and looking at the slicer output to make sure seams are as “hidden” in non-critical places as possible. Here are a couple of “Before & After” Seam pics [LW-PLA - Seam Printing - Album on Imgur]
Well with no retraction, first layer printing is a mess as you can imagine! First layer printing (including brims and the pre-printed border lines) cause “blobbing” and stringing. But none of that really interferes with the actual printing once it starts to build up from the first layer. And LW-PLA is really going to do that anyway even with Retraction enabled!
Finally, let’s close this out and recap some other settings and printing tips:
- I didn’t touch any of the Cooling settings - they are all left at Default. I haven’t seen any issues with bridging or overhangs.
- Just a reminder that I also haven’t changed any of the Speed settings. As long as I set the Max Volumetric Speed at 5, I can just let the X1C run on the default Standard settings.
- For tall, thin, single perimeter models like these plane files, they really need a Brim to add adhesion and rigidity. I am using a 5mm Brim with a 0.1mm Brim Object Gap. I haven’t had any print failures and the Brims detach easily. I’m printing on a Wham Bam PEX build plate and get excellent adhesion with no assistance (no glue stick, etc.).
- Most of LW-PLA advice I saw (at least for plane prints) recommended setting the Wall Generator to “Classic” and not using Arachne. I use Classic for my LW-PLA printing.
- You cannot run Flow Calibration before printing on LW-PLA at your “expansion” Nozzle temp. The printer will attempt to adjust the flow for the “expanded” filament height. I honestly don’t know if Flow Calibration is necessary at all using the calibrated print settings (maybe someone can weigh in on this), but I decided to “play it safe”. I changed the filament settings to lower the Nozzle temp down to 190C and ran my test print with Flow Calibration turned on. That would print the Calibration filament in an “un-foamed” state. I let it print long enough to lay down and analyze the calibration pattern and then stopped the print. I figured this would “capture” the flow calibration for the filament before expansion and save it in the printer settings. It’s probably totally unnecessary …
- There is one weird setting change that is required to print the Eclipson files. A lot of the internal structures are drawn using very small dimensions and they “disappear” during slicing. The “Slice Gap Closing Radius” has to be set to 0 under the Quality settings to get these to work. Also be aware that some design files (notably 3DLabPrint) require using the “Even-Odd” Slicing Mode under Special Modes.
Here is the actual Eclipson print “in progress” using the final settings [LW-PLA Eclipson Model S "In Progress" - Album on Imgur]
And if you want to see my actual Filament and Slicer settings you can go here [LW-PLA - Filament & Slicer Settings - Album on Imgur]
Sorry this is so long! I want to stress again that all of this has just been based on my personal experience, and it represents my “simplified” approach to printing with LW-PLA (specifically for model planes). Like everything else with 3D printing, there are always a lot of different ways to do something and not just one “right” way. I welcome any and all comments and advice and definitely need you to point out any mistakes or errors I have made. I also really appreciate all the information that has been posted on the subject of LW-PLA from people who are a lot smarter than me - I couldn’t even have gotten started without you!