Very interesting! I watched another video. He sort of disproved the moisture idea and sort of proved that UV light has the ability yo make the filament brittle. But he did not test this. And I think you got some really interesting results here!
Thanks for the follow-up, this added some insight for me for sure. Now I just wonder if anything can be done to fix it? According to Tom's 3D acetone can slightly soften some brands/colors of PLA (but not completely dissolve obviously). Might be worth a test now that you have demonstrated that mechanical stress is a significant factor. I have an old roll of Hatchbox PLA which has become super brittle and very difficult to use unattended. Oddly, other rolls of Hatchbox of a similar age are not problematic at all.
For me there isn't really much practical use in a solution other than "don't force it to be out of shape". If it's a necessity for some machining I'd go with a (vinyl?) modified PLA or some other plastic (PETG, ASA, or HIPS). Trying to force it back into usable condition might make a neat project, though! Ah, so with the Hatchbox that'd be a different cause. I mean. Unless the whole roll was held relatively straight somehow :). I've seen that happen from a manufacturing problem which I assume is just improper heat cycling when it's spooled up; not much to be done there. You could probably also cause it with UV damage to the plastic over time. Some folks have posited that you might get brittle PLA from moisture as well but I assume you'd hear the steam when it was printing. It still might not hurt to bake it as if it was moisture, regardless, and see if it comes back.
No problem! I made the connection when I watched a production facility video, either Tom Sanladerer interviewing someone or Prusa when they spun up the production lines. They explained that it has to have its final shape for the spool while it's cooling for the same reasons.
I had a whole spool of green pla disintegrate on the shelf without being touched, just left on there, opened. It literally fell to 3-4 cm pieces with no mechanical stress applied. There’s surely something else as well besides the mechanical stress of simply straightening it…
Ah, that's the same problem but with the winding or cooling process at the factory. If it's spooled up at the wrong temperature the plastic has already set up. Brittle as all get out at that point after it sits packaged for a bit and it'll just shatter on opening.
@@PCBurn Actually no, when opened it was flexible and not brittle, we printed a few things and shelved it since we don't use that green too often. Must have been a month or 2 on shelf before one morning coming in and seeing small bits of green everywhere under the shelf. Whatever happened, happened over the span of 1-2 months just sitting there at room temperature. Maybe there's some oil in there that evaporates with time, maybe it has to be kept not fully dry, I don't know, but something's fishy :D
@@The-Weekend-Warrior Yea. There are other things that can happen to plastics. But not many aside from stress that cause it to shatter. More moisture will make it print horribly but I haven't actually seen it embrittle PLA. The Internet is littered with "but of course" claims of that that then go on to explain the print problems with no explanation as to why it would be brittle (and it can't be *that* brittle if they then use it to test printing). UV exposure might do it. Although I'd be surprised if that happened to the interior of roll. I'd still go with manufacturing defect that took time to play out without anything else to go on. But of course that's just based on my experience handling and forming plastics; I don't run a test facility! However... a video on moisture exposure over time wouldn't be a bad idea. It'd take a few months to really test but I think I've got the perfect area to set it aside now.
@@PCBurn I suspect that these rolls of PLA behave nicely within a range of moisture. Too much and you print ugly prints and too little and it gets brittle, but this is just a hunch. If there are oils in there that evaporate or dry after you open a roll, this can have the same effect I guess... our place was very dry. Everyone claims that you have to dry your rolls, but do you? Is too dry a problem too? Worth exploration I guess.
@@wernerviehhauser94 moisture will cause nasty issues as well. But not normally snapping filament with PLA as is the case here. From air exposure. I assume that during moisture testing the PLA might be held out of shape causing this mechanical stressing embrittlement issue in addition to whatever test is going on. One might be able to change the mechanical properties of the entire unspooled roll by drastically changing its moisture content. Or it could have been poorly spooled in the first place. That'd be a heck of a lot more involved to tease out in a moisture test.
@@PCBurn i was mostly going about those 100+ posts I read researching this topic after I spent quite some time opening and reinserting the filament in multiple of my samla boxes where the filament broke when I changed colors... every time... inside the box. Someone doing less thorough searches would be convinced that "putting the filament in the food dryer" solves the problem by drying, whereas it might just be solved by releasing the mechanical stress through temperature or might actually not be an issue at all for the rest of the (unstressed) filament, wasting time and energy. I was even considering that the PLA might be TOO dry (I get down to 20-30% rel.H. in the boxes), but the cheap white PLA that has been sitting unused on my desk the whole humid summer prints like a charm - and that's where my inner physicist called and demanded a thorough analysis. I didn't really think that much about the topic, since for the last 4 years I have mainly been printing functional parts with 1 spool in use, 1 on backup and storage was not an issue.
@@wernerviehhauser94 absolutely. That's a similar sequence of events that led me to see what would cause breakage... I had noticed it was only with PLA and a damp roll spitting puffs of water vapor when used didn't crack up.
Thank you dear sir! I replicated your experiment and got straightened PLA snapped too.
@@BriskPebble thanks for the feedback!
Very interesting!
I watched another video.
He sort of disproved the moisture idea and sort of proved that UV light has the ability yo make the filament brittle.
But he did not test this.
And I think you got some really interesting results here!
Thanks for the follow-up, this added some insight for me for sure. Now I just wonder if anything can be done to fix it? According to Tom's 3D acetone can slightly soften some brands/colors of PLA (but not completely dissolve obviously). Might be worth a test now that you have demonstrated that mechanical stress is a significant factor.
I have an old roll of Hatchbox PLA which has become super brittle and very difficult to use unattended. Oddly, other rolls of Hatchbox of a similar age are not problematic at all.
For me there isn't really much practical use in a solution other than "don't force it to be out of shape". If it's a necessity for some machining I'd go with a (vinyl?) modified PLA or some other plastic (PETG, ASA, or HIPS).
Trying to force it back into usable condition might make a neat project, though!
Ah, so with the Hatchbox that'd be a different cause. I mean. Unless the whole roll was held relatively straight somehow :).
I've seen that happen from a manufacturing problem which I assume is just improper heat cycling when it's spooled up; not much to be done there.
You could probably also cause it with UV damage to the plastic over time.
Some folks have posited that you might get brittle PLA from moisture as well but I assume you'd hear the steam when it was printing. It still might not hurt to bake it as if it was moisture, regardless, and see if it comes back.
This explains a lot! I never made the connection but it totally makes sense now.... Thanks for doing this :)
No problem! I made the connection when I watched a production facility video, either Tom Sanladerer interviewing someone or Prusa when they spun up the production lines.
They explained that it has to have its final shape for the spool while it's cooling for the same reasons.
Great video!
Thank you!
I had a whole spool of green pla disintegrate on the shelf without being touched, just left on there, opened. It literally fell to 3-4 cm pieces with no mechanical stress applied. There’s surely something else as well besides the mechanical stress of simply straightening it…
Ah, that's the same problem but with the winding or cooling process at the factory. If it's spooled up at the wrong temperature the plastic has already set up. Brittle as all get out at that point after it sits packaged for a bit and it'll just shatter on opening.
@@PCBurn Actually no, when opened it was flexible and not brittle, we printed a few things and shelved it since we don't use that green too often. Must have been a month or 2 on shelf before one morning coming in and seeing small bits of green everywhere under the shelf. Whatever happened, happened over the span of 1-2 months just sitting there at room temperature. Maybe there's some oil in there that evaporates with time, maybe it has to be kept not fully dry, I don't know, but something's fishy :D
@@The-Weekend-Warrior Yea. There are other things that can happen to plastics. But not many aside from stress that cause it to shatter. More moisture will make it print horribly but I haven't actually seen it embrittle PLA. The Internet is littered with "but of course" claims of that that then go on to explain the print problems with no explanation as to why it would be brittle (and it can't be *that* brittle if they then use it to test printing).
UV exposure might do it. Although I'd be surprised if that happened to the interior of roll. I'd still go with manufacturing defect that took time to play out without anything else to go on. But of course that's just based on my experience handling and forming plastics; I don't run a test facility!
However... a video on moisture exposure over time wouldn't be a bad idea. It'd take a few months to really test but I think I've got the perfect area to set it aside now.
@@PCBurn I suspect that these rolls of PLA behave nicely within a range of moisture. Too much and you print ugly prints and too little and it gets brittle, but this is just a hunch. If there are oils in there that evaporate or dry after you open a roll, this can have the same effect I guess... our place was very dry. Everyone claims that you have to dry your rolls, but do you? Is too dry a problem too? Worth exploration I guess.
The tube is PTFE, not PLA… :)
I also have trouble with the Sony Genesis console :). Although I usually asterisk them in post!
Well, that basically shoots down all those "moisture" fanbois.....
@@wernerviehhauser94 moisture will cause nasty issues as well. But not normally snapping filament with PLA as is the case here. From air exposure.
I assume that during moisture testing the PLA might be held out of shape causing this mechanical stressing embrittlement issue in addition to whatever test is going on.
One might be able to change the mechanical properties of the entire unspooled roll by drastically changing its moisture content. Or it could have been poorly spooled in the first place. That'd be a heck of a lot more involved to tease out in a moisture test.
@@PCBurn i was mostly going about those 100+ posts I read researching this topic after I spent quite some time opening and reinserting the filament in multiple of my samla boxes where the filament broke when I changed colors... every time... inside the box. Someone doing less thorough searches would be convinced that "putting the filament in the food dryer" solves the problem by drying, whereas it might just be solved by releasing the mechanical stress through temperature or might actually not be an issue at all for the rest of the (unstressed) filament, wasting time and energy. I was even considering that the PLA might be TOO dry (I get down to 20-30% rel.H. in the boxes), but the cheap white PLA that has been sitting unused on my desk the whole humid summer prints like a charm - and that's where my inner physicist called and demanded a thorough analysis. I didn't really think that much about the topic, since for the last 4 years I have mainly been printing functional parts with 1 spool in use, 1 on backup and storage was not an issue.
@@wernerviehhauser94 absolutely. That's a similar sequence of events that led me to see what would cause breakage... I had noticed it was only with PLA and a damp roll spitting puffs of water vapor when used didn't crack up.