HT-PLA for a Server?

[earnest stone]

I'm planning on designing a custom NAS enclosure. The air temperature should realistically never go above 80C, and I thought that HT PLA could be ideal for this build. Could I run into problems? Should I consider the GF variant for some reason? Any input is very welcome!

[opal verge]

What needs to be considered is how much load will be on the parts compare to the part geometry

[earnest stone]

Would it perform better or worse than standard PETG?

[vast breach]

If the part will have to hold the weight of something for a sustained period of time, i'd trust PETG more

[earnest stone]

I see. That is a bit confusing to me because based on te stats and experiments I've seen, I would think that HT PLA should hold it's shape at higher temps than PETG

[median rock]

maybe with lower loads yes but higher loads no

it's the difference of semi crystalline and amorphous

[earnest stone]

Anything printable on an open printer that would be suitable? Or am I just pushing it too far

[median rock]

I mean load the plastic part is holding moreso

[earnest stone]

Not sure I understand

[median rock]

is the ht pla going to support anything or is anything going to be bolted to it?

[earnest stone]

It would have to. It would hold... well every component. I'm not sure how high the temperature will get but I could and would incorporate a lot of airflow for the electronics and the plastic. But yeah... it might be too much mass for it to hold well.

[median rock]

if it's a mesh pla ht dust sceen, it might hold its shape better than petg, if it's a fan bolted to the mesh screen then it'll probably not hold its shape and warp

[earnest stone]

We're talking about an entire custom enclosure

[median rock]

yeah it's up to you to judge how much load it'll take but low to no load it'll hold it's shape. With any load, pla is more like play dough at higher than 60ish

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[earnest stone]

Surely Polymaker's HT-PLA would hold well above 60?

[median rock]

the other end is if it's at 120c or so for example, the abs will probably stop holding it's shape while the pla will (with no load)

[earnest stone]

And I really doubt the temperature would go above 80, I could probably keep it lower but that depends entirely on the HDDs

[median rock]

that is annealed ht pla gf from polymaker

[earnest stone]

I see. Well.... then I don't know if this project is feasible

I don't see PETG holding at all. I'm not sure about ASA, though I am sure it'll be a nightmare to make something so big on an open printer with ASA

[median rock]

ASA would be the highest chances I'd think but you'd have to test it at load and temps to see

[earnest stone]

I'm not sure I'll manage to print something so big with ASA but I guess I could try

Though I think I'll give HT PLA a shot with a lot of airflow around the plastic

Although it's seeming more and more dangerous to go for this. After all, if there's a cooling issue or just very slow deformation, it could lead to catastrophic consequences

[median rock]

If it helps you to understand it a bit more

Glass transition is where plastic goes from glassy hard to rubbery/viscous state

Asa and PETG is amorphous so when it gets to tg it’s like frozen honey to liquid honey transition

And ht pla and other semi crystalline (like little crystals in it) go above tg and hold their shape for a bit longer despite losing the frozen state strength

-like adding a lot of corn starch to thicken honey where it becomes like putty (starch particles are like thousands of tiny crystals dispersed in plastic)

[earnest stone]

I see

Thanks!

So HT-PLA is moer useful for decorative prints and transport safety than structural heat resistance, despite holdings its shape longer than ASA without load

[median rock]

The video I sent was at 80 where abs still springs back and you can’t mold it like putty or clay (frozen state)

But pla ht is in like a clay state that bends and stays without springing back if load is high enough

[earnest stone]

So perhaps an ASA composite would be best suited?

[median rock]

yeah cause asa tg is closer to 90-100 (but it weakens as it gets closer to it) and falls off a sharp cliff after it (frozen honey to liquid honey melt)

and this is at 150, where abs (in the vid but same as asa basically) has gone past the cliff and becomes liquid honey but ht pla is still in like starch mixed putty state that's still mouldable but holding its shape

[earnest stone]

I see

[median rock]

so like an example is ht pla fan grill won't sag and melt at 150 like the abs

but if you have a fan mounted and pulling on abs and pla ht at 80C, abs will hold it and not deform but pla will probably start sagging permenantly

And this is it cold/below the glass transition point

Does that kinda make sense?

[earnest stone]

Yes it does

Thank you so much

[median rock]

Gl!

[opal verge]

Sorry missed the convo, but it’s all about the load VS the geometry, if you have a pretty bulky design it will hold much more than super thin brackets for example 🙂

I didn’t caught up on the convo above but let us know if you have further questions 🙂

[median rock]

The printbusters you mentioned should probably do an episode on the above haha it’s pretty confusing to most and is kinda what you need to explain about heat stability vs strength with heat under high load

Have a look at the videos

[opal verge]

For sure, I ll definitely do an episode on explains polymer behavior under heat.
(Considering factor such as: Time, geometry, temperature, crystallinity degree, load, ..)
It’s going to be fun 😄

[earnest stone]

Thank you. Well I'm still unsure on how to go about this so if you have anything to add I'm all ears. I primarily have to decide what filament seems most suitable for such a build

[vast breach]

I was referring to creep as well, not thermal resistance. PLA is quite prone to creeping under mechanical load. Things like weight, belt tension, screw pressure, etc.