FWIW Ryan uses Hatchbox PLA for all the printed parts he sells. My machines are printed in Overture PLA. And i have done a fair amount of aluminum milling on both of my LR3s with no issues. And they are in a garage that gets to 95º in the heat of the summer with no issues at all (other than me overtightening things but thats not the filaments fault lol)
I think every time I see someone using a new filament other than PLA, a few months later they come back and share that they are reprinting in PLA
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I’m firmly on the side of just building it as spec’d unless you have a really good reason not to, or are having a problem with it afterwards.
I don’t remember seeing anyone that bought their parts in PLA from Ryan coming back with any PLA specific issues on the forum
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In general carbon fiber will stiffen PLA, but manufacturers may change the formulation to get it to print better. You might take a look at CarbonX PLA filament. The datasheet shows a Young’s modulus of 4950 MPa.
I think the best course is to just print with PLA. Avoid matte, “tough”, “terra”, and “eco” types. Just regular old PLA with nothing special added. The only thing that might do slightly better is Polycarbonate but 1) it’s expensive 2) it’s not easy to print with 3) it doesn’t bridge well and 4) may have some issues with tolerances.
I did use Prusa’s PC Blend for a few parts, but I don’t know that it was necessary. You just can’t beat standard PLA for the value, print accuracy, and stiffness.
Oh and nylons should be at the very bottom of the list of filaments, even CF ones.
My .02
OK you are doing research. That’s good. To be sure PLA is the best choice since the parts were designed for the material and that is what is supported. Remember these parts are large and uneven temps within the part becomes a consideration.
Anecdotally, I can say stay away from PLA, ABS, ASA as CF negatively affects layer bonding. Your parts will crack eventually. I’ve only had luck with CF variants of PETG, PA and PC and in this application the CF is necessary to produce the overhangs these parts require.
PC-CF is really hard to print if you don’t have a really toasty chamber - at least 60°C throughout. I’ve never printed large PA6-CF parts - only small parts - but I’d imagine it’s a similar situation. For the money PETG-CF is a wonderful material. I’ve used it for LR2 parts and it worked phenomenally. More rigid than PLA, higher heat tolerance and superb layer bonding.
All this to say PLA is spec and that is what you should use. If you want to experiment go for it. It’s a lot fun to learn and use new materials. But be prepared to print everything again in PLA and rebuild your machine if it fails.
Do you mean heat creep going up in the extruder?
I see you have a enclosure. It is easy to get PLA to hot in an enclosure and cause heat creep .
I think he means deformation under load over time. One way to test is to make a hook, hang some weight off of it and measure deformation over time. You are measuring how the plastic keeps the deformation after the load is released. Most plastics will creep over time. Some are worse than others.
@brenavich980 PETG-CF is interesting with some products like 3DXTech CarbonX CF PETG but not very impressive with other CF variants like Atomic CF PETG (which I love but not for stiffness). Good CF filaments are often stronger in the direction of the CF strands but pretty much the same as the base plastic in the other direction. So layer orientation to the load is a big factor on whether the CF helps or does much of nothing. In addition, the CF does impact layer adhesion which can make the part fragile between the layer lines.
CF PC like Prusa’s blend is the ultimate in some ways but it needs a printer that can print it and it does have some issues bridging just because of the print temp. Manageable but not a set and forget thing for complex parts with lots of bridges. It also does have some shrinkage, though again manageable.
Nope, I meant parts that worked fine for a while then just… broke in half a month or three later. It’s why you never use PLA for shelf brackets and stuff.
My current build is a 525 that I printed with random PLA I had lying around and it could definitely use more stiffness, but I don’t know how much of that is the 525 being the first design, not using enough perimeters or infill, etc.
I’m not really questioning whether it’s going to be stiffer, more whether stiffness of the plastic parts is anywhere near the top of the list in terms of stuff I should pay attention to when building up a Primo and trying to maximize rigidity. I could’ve done a better job stating that clearly.
Looking at Polymaker’s materials at least, what you’re saying matches up with their tests for PLA but not for Nylon - PA6-CF has the highest Z-orientation tensile strength of everything they’ve got:
Nylon deforms when you pull on it so it doesn’t just break dramatically. Good layer adhesion is a factor too in Z. It’s not related to rigidity.
I’m aware that it’s generally very ductile, but supposedly nylon CF ends up as the best of both worlds. I think my biggest concern is that it may soften due to hygroscopy.
Hydroscopy is definitely a factor. I’ve wanted to try the PA11 from Prusa and see how it does. Supposedly less so.
But really, the only thing you are gaining over pure PLA is heat resistance. If curious, all you can do is do some test yourself. I think you’ll find it’s hard to beat PLA no matter what those charts say
I should add…I was asking all these same questions before I built mine. I wanted to find the “best” filament and decided the only way to get there was do the tests myself on the filaments I was interested in. I would have used ANY filament at any cost (well mostly anyway) and after hours and hours of testing ended right back at PLA.
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Yes 3DXTech is all I use when it comes to the engineering type materials. Worth the cost. And you’re right about the moisture content. PC, PA and even PETG need to be dry, dry dry. If you don’t have a way to dry and keep them dry don’t even bother experimenting with them - even if your going to use them right out of the bag brand new.
FWIW, here’s the material properties comparison sheet for eSUN. I couldn’t find it on their site, but it’s included in the box with each roll from them and I didn’t notice it until recently.
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I would be curious to see how onyx or any other CF filled nylon performs when printed at a higher infill. The Markforged printer uses a proprietary slicer that encrypts the gcode, the proprietary slicer only lets you go up to 38% infill.
Thats me! Other than the core, I printed that on an SLA printer out of a ceramic filled resin and the core is awesome.