Material properties at thermal extremes

General Discussion
1

Hello everyone,

I am looking for some specifications on how certain resins (namely: Tough) will behave at low temperatures (like 0 deg F). We have printed a few prototypes with the tough resin and cured them in the Formlabs curing gizmo. Almost immediately, the parts cracked when we put them into service in the cold environment.

Right after the cure, we tried to break them by hand and could not. It was one of those Sword In The Stone things where everyone in the office was watching someone try to break it thinking “what a weak man, give it here and watch me snap it”. No one could break it. Every person present was an instant convert, going forth to their respective township proclaiming the merits and righteousness of the Tough resin. Many of these people are self-proclaimed 3d-print skeptics having been exposed only to shi*** FDM prints before. (X-sectional area of the area seeing the bending moment was maybe 300 mm ^2)

The elation quickly faded as we broke, almost immediately, each of the parts while installing them in the frigid temperatures of the freezing Midwest US.

I have been trying to find a more detailed data sheet that would give me things like yield strength / Young’s modulus as a function of temperature as opposed to a single snapshot of these properties at an unknown temperature. My search of the forum turned up only subjective anecdotes such as “at -5F … I wouldn’t expect it to augment the impact strength and other mechanical properties to a significant degree”. But it was significant.

Again, we are using Tough resin cured per formlabs desired methods and subjecting the printed parts to 0 deg F temperatures.

The current converts were won with ease, but will be held with difficulty

2

Yeah… I once watched a rose shatter like glass after being dipped in liquid nitrogen.

I would avoid materials that are meant to be extra rigid at room temps- and try the Durable resin- I tried printing something with a snap fit in Durable, but at room temp it was just way too bendy to " click"
But I am sure that at colder temps its performance would come closer to the tough resin.
I have printed 4" diameter cylinders with 1/8" wall thickness in Durable and I can deform them out of round if I squeeze them really hard, but they WON’T crack or break. I imagine they would retain more resistance to fracture at low temps than something that starts out much stiffer.

3

How are the parts shattering? Are they breaking when you bolt them on or when there are loads applied?

In my experience you can’t crank down bolts on any printed part with the same torque as a good plastic or aluminum piece. I would cast anything that needed to be strong at that type of temperature and even that would be a gamble. (print mold, cast part)