PLA Light As Foam CHALLENGE - Foam vs PLA vs LW-PLA 

Thank you I appreciate that.

and price comparison... LW-PLA aint exactly cheap, not foam board cheap...

@@timm1065 LW-PLA isn't cheap, but it looks a lot worse than it really is. Since you only print at ~50-55% flow, you can build twice as much with 1kg of LW-PLA as you can with 1kg of regular PLA. I'm currently printing the Eclipson Model C, which should come it at around 240g of printed material in LW-PLA, where the regular PLA version comes in at 470grams...

Depends where you live, foamboard here where I live is expensive and heavy. LW-PLA is a much better option.

You can find a lot of the properties of different materials on eSuns website. The two parameters important are the density and the yield stress (they only quote tensile and flexural strength, but they are close enough for ballpark figures). The tensile strength of PLA-LW is approximately 32MPa. For regular PLA we are looking at approximately 72MPa. The density on the roll for PLA-LW is the same as regular PLA at 1.2 g/cm^2. However when foamed it drops to about 0.54 g/cm^3. Technically the yield strength is already independent on density, and thus we can pretty much say that PLA-LW has about half the yield strength. But that doesn't tell the whole story. This assumes a constant stress (i.e. force per area), which is often not really the case. Usually the force is the same, and because of foaming PLA-LW has a lower density (and thus higher volume) meaning larger surface area for same applied force. If we print at approximately half the density, we would need to print twice the volume for the same weight. However, assuming a cube shape, this would only mean an approximately 1.6x increase in surface area over which the load is spread. So if we have the same force applied to the structure, because of the 1.6 increase in area, it experiences a 1/1.6x decrease in stress. So for example if a PLA wing breaks at 10N applied at a point, a PLA-LW wing at 100% density would break at approximately 4.44N. However if foamed to about 50% it would be able to bear about 7.11N of load. As you can see just foaming the material helps, even at the same weight, because of the increase in surface area. Again! Note that this doesn't mean that foamed PLA-LW is stronger!! It should also be noted that this is with 'slow' static loading. Actual real life loads are very different. I presume that the largest load of a model plane is at impact with the ground which can often cause rapid uncontrolled disassembly of your aircraft. For these kinds of shock loads its not just yield strength that matters, but also the elasticity of the material. To measure impact strength there is an impact strength test (IZOD), which is also a measure per unit area. This is 8.58 and 5.4 kJ/m^2 for ePLA-LW and PLA respectively. This shows that for impacts, PLA-LW is probably much better than regular PLA (~160% of regular PLA), even at 100% density! At half the density (and thus 1.6x the surface area), assuming a similar force impact, foamed PLA-LW is likely 250% better than regular PLA. tl;dr I suspect that foamed PLA-LW is about 70-80% of the structural strength/weight ratio of regular PLA. Foamed PLA-LW likely ~250% of the impact strength/weight ratio of regular PLA though, which is likely much more important.

@@tHaH4x0r Amazing response. Engineer?

Thank you, I have been interested in trying to build some small micro indoor rc planes with this material. It really is awesome stuff it is so light. Cheers

Wow that sounds like quite the project. Yes I agree it would have been nice to have some type of balsa wing for this project also. I think the best configuration would be with some sort of hybrid between LW-PLA and a carbon fiber spar of with a PLA spar. I look forward to hearing about your future builds.

Yep. And stronger. Also try carbon fiber. Lighter and stronger still.

yes but balsa, carbon, or foam also.. all require more time to make than just print the wing while you sleep, so that is also one thing to take into account

hahah Thank you

Thank you for the comment, 2K a month is a lot of printing!! Cheers

@@TroyMcMillan I know, I need to get as better hobby, right after I print.....

I did not add any holes in the inner structure so that I could print the LW-PLA without stringing, I print these in vase mode so there is no retraction.

@@TroyMcMillan Stringging is more of a "cosmetic" issue than a resistence issue... I do have the stringging inside, which doesn't make a difference, and saved a lot of weight, without loosing much resistence... Besides, after tuning it, I almost have no stringging... The weight saving is worth it. Check the airplanes from 3d labprints, theirs are optimized for printing and low weight. Have a couple printed in regular PLA, and I can't wait to have the time to print one of them in LW-PLA! It should have a big boost in performance

Today we do but very expensive, rn i trying my luck with abs, been finding it cheaper and more heat resistant than regular pla

heck ya LW-PLA is awesome

Thank you Robert I appreciate it take care

@@TroyMcMillan ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-l4JqDHwgdzow.htmlould be a great project for in the future Troy would get lots of traction view wise

I am just finishing up on fuselage

@@MrZeek101 Nice, The Fuselage takes the most work.

@@MrZeek101 Ya that is a good idea. Thank you for the tip for a video. I don't have FPV equipment and have never tried it out. May have to get one.

Thank you

I would bet that it's a tad bit stronger than foam. So you worry on LWPLA but not foam? If it snaps out, so would foam.

@@StupidusMaximusTheFirst the materials have very different breaking characteristics. It's not about raw strength

@@lu4414 Yeah, you're probably right on this, it's not just about strength, and they might have different properties. And sometimes, way too much rigidity over what you want might not be a good thing I suppose. I'm new to this.

Thank you

Ya I have had a few people recommend this. PLA is definitely stronger that LW-PLA. I may try something like this in the future.

I is Mursha Reservoir in Las Vegas

Thank you

WOW I like this idea I have not seen anyone try this out. I will have to give this a try. Cheers

this is true. But there are some really neat looking 3D printed planes!

Yes i may do some more testing to test the strength a bit more. This video was just to show the wight difference mainly.

I actually built the Eclipson model A that was my first build with LW-PLA. LW-PLA is not as strong as PLA so for some builds it will not work as well. It really depends on the designer that makes the STL files if the plane can be printed in LW-PLA. Eclipson planes use LW-PLA and PlanePrint uses PLA. You can print PlanePrints airplanes out of LW-PLA but it will not work as well because of the way the plane is made. With LW-PLA you can not use as much retraction and can't eliminate stringing so there is a special way Eclipson makes there planes to work with LW-PLA.

You dont need washout on a square wing - they are not conductive of tip stalls.

I did not use any washout. This was just a wing I designed out of foam and I copied it for this 3D printed wing.

I design the wing so the extruder never retracts. I printed all these parts in vase mode in Cura.

I print this wing in vase mode so there is no retractions.

Can u set the printer to print in vase mode is that something u did in the cad design

Thank you for the suggestion I have gotten a lot of people asking me to do this. I will test them some more.

Thank you, I have only been using TPU hinges since the Bobber build so I have not used them for a long enough time to say. I have not had any problems with them yet. Merry Christmas

I don't print with any support. There is just a wing structure I designed in the middle of the wing. I don't use any. spar.

Only place I can find it is on ColorFabb website.

@@Pics2FlicksDennis okay thank you!

Nice I like the wing shape

@@TroyMcMillan The shape is functional, not aesthetic. Also not my first try. Simple plates and curves buckle, with thin walls. Adding ribs adds weight, and still tends to buckle. Compound curves are self-supporting, with less material, and yield the lightest solution. Old knowledge - the auto industry got deep-draw alloys for steel stamping back in the 70s, and were able to reduce cost and weight using stamped (self-stiffening) compound curves.

Looks like Fusion 360

Fusion 360

I am not sharing them right now sorry!!

Las Vegas Dry Lake Bed

@@TroyMcMillan ok i thought it was here in cali.

I like what you are thinking. It is too bad, though, that it would increase strength instead of reducing weight. I have searched for anyone building LW-PLA structure with shrink covering (and maybe with some carbon fiber rod reinforcement). That would be interesting.

It resists heat much better than normal Pla, but temperatures below 10 Celsius are dangerous- it gets brittle!

I am in Las Vegas. I fly at Mursha Reservoir dry lake bed.

@@TroyMcMillan Nice It looks very similar to the Santa Clarita Palmdale area I'm at

I am not posting the STL files as of now.

@@TroyMcMillan sad, but I understand

Come summer time PLA and LW-PLA are going to suffer warping no matter the color. Looked like he was already getting some.

colorfabb is now selling LW-ASA. As far as the LW-PLA goes from my experience with the materia, the natural white LW-PLA seems to be able to hold up to a hot sun, while black LW-PLA will warp like a vinyl record in the backseat of a car on a hot day.

@@wfpelletier4348 Yes this is correct I have not tried the LW-ASA I have had experiences with printing PETG and it warps badly on the print bed. ASA has a tendency to warp also. I have not had any problems with Natural LW-PLA melting in the sun.