PLA Filament Breakage

Has anyone had any experience or have any information on PLA filament breakage?

By this I mean breakage in multiple places whilst still coiled on the spool. I had this some time ago with a coil of blue filament. In the end, I threw it out and moved on.

Today I noticed a break in the filament about 9" from where it entered the printer while I was about half-way through a 6-hr print using a coil of black filament. Luckily I was around to notice at the time and was able to pause/re-thread/restart. Then I noticed more multiple breaks sticking up through the coil on the spool. Again I was lucky - the printer finished the print about 6" before the next beak. Another coil to throw out.

In this case, I had re-wound the filament (without issues) from a larger spool to a smaller one (using my ML7) and I know there were no breaks at that time. They have developed since while on the spool. The coil was wound relatively relaxed - not over-tight.

Google searches show that others have seen this problem but the details are mostly subjective/anecdotal without much information on the hows/whys/what-to-do.

Not had this problem but have read that PLA is biodegradable and can breakdown in sunlight. It is not recommended for use outdoors.

Paul.

The filament is dry before you bin it , give it a 5 sec dip in boiling water then let it dry

Some filament does not seem to like a change in spool diameter and can break as a result of the new pressures.

I regularly come back to my Prusa i3 clone after periods of non use, sometimes as short as a day or two, to find that the filament between the spool and the hotend has snapped, often with a 3-6" piece having broken off and 'pinged' across the desk.

I have a length of filament in a bowden tube on my Kossel Mini that having been left for a long period of time has snapped at intervals of about 2-3 inches along its entire length from the hotend back to the extruder motor.

I also recall reading one of Richard Horne's blog posts where he had an entire spool of 3mm black PLA shatter.

Richard also has another post about a filament joiner that he uses for multi-coloured prints that he has also put on Thingiverse, he has a separate post where he posts additional information about calculating how long each coloured piece needs to be prior to joining them up.

If it breaks like spaghetti then i think this means the filament has been exposed to damp. I never had a roll do it but i have had those 5M samples from China do it. Best place for it is the bin unless you want to try drying it in the oven. Dont get it too hot or you'll end up with a big lump of plastic. Humidity and filament dont mix. All my rolls are in zip lock bags with silica gell. Never leave a roll on a machine when not in use. Any moisture will show up on your prints as the damp turns to steam in the hot end. Humidity today 68 %

regards

Steve

Agreed.

My understanding is that it is excessive moisture content NOT dryness that causes PLA filament to become more brittle.

This is one reason why filament is supplied sealed in a package with a silica gel sachet.

The other reason is that damp filament will create pockets of steam as it is extruded, greatly degrading print quality. This is a big problem with nylon which is very hygroscopic but can affect other filaments as well.

The solution is to dry the filament in a low oven for a few hours, but note that PLA has a relatively low glass transition temperature (well below 100c) so the best solution is to keep it in a dry atmosphere as much as possible.

I have it in mind to experiment with ways to allow direct feeding of replacement filament without extracting the old 'stub' first by modifying my Mk8 extruder.

You can also get add-on broken filament detectors.

Neil

May be it depends on the source of the PLA? Over the years I've used quite a few reels of PLA, and I've got 10 odd reels sitting on the living room floor, some open, some not. I've never had a breakage or voids due to steam. All my reels are by Colorfabb.

Andrew

There is very little cost to cutting a meter or two and giving it dip in boiling water. so i see no reason for anyone to just desregard this without testing, it has worked for me

Pete,

While dunking in hot water may alleviate the problem, it likely causes more elsewhere. Most advice is to keep water away from filaments - all, not just PLA!

Here is a link to a beginners internet page, on the subject. It might be of interest to you. Perhaps your items do not require a perfect surface finish? Perhaps you go to great lengths to desiccate your filaments after dunking? I know nowt much about 3-Dprinters, except what I read.

**LINK**

I had a reel of Black PLA 1.75mm that appeared to have brittle regions, it would print OK for a while then I would come back and find it had snapped !

I did place it in the slow oven of the Rayburn for a couple of hours to dry out, no real solution it would break again after a few hours of printing

In the end I just put it in the bin rather than spending any more time or loose any more days with failed prints.

IT was the only brittle problem reel I've had in 3 years of 3D printing [Can't recall the make/brand]

I keep my reels in plastic bags with the silica gel bags, and if the printer isn't to be used for a while I will remove the reel and bag it.

I find different brands respond differently. I keep my filament is a sealed plastic box with a disposable dehumidifier in it. I've used a LOT of filament now and only had one reel that had fragility issues.

My office (were the printer is) is quite a 'dry' environment, small and warm.

Neil

Sorry to be late back to this - combination of time-zone and "things".

Good discussion but I'm not sure it gets me much farther than the Google search.

- I do (now) purchase most of my filament from a reputable local supplier (filaments.ca) which specialises in 3D printing. However, I can't track either the blue or the black PLA back to them through my online purchases records. In that case I probably got them at an electronics store a few blocks away which has a shelf of filament. That filament has been sitting there for some years now and I no longer use them.

- Like Neil, I keep all my filaments in seal-able plastic containers along with some desiccant.

- I do have a commercial filament drying oven which I use with ABS but haven't so far used with PLA.

- The printers (4) are used in my workshop which is in my house basement and included in the house heating/AC system. The environment is therefore pretty benign: neither too hot nor too dry. Nor is it in sunlight.

I gather I should either keep the PLA dry ...... or perhaps moist. It frankly isn't clear to me what dunking some in boiling water is supposed to show. Does it get brittle or flexible? Since putting it in boiling water must be way outside any specified operating conditions, does it actually prove anything anyway? Maybe I just didn't understand what was being said there. (I chuckled about the "meter or two" with this spool. I think the longest continuous length I could get off the spool would be 6" - perhaps less).

It seems to me that if this were a frequent problem with PLA, there would be more information out there. That the info is rather sparse suggests that, whatever the cause, it doesn't affect the bulk of the material being sold. So I guess I'll just write this off and move on (same as I did for the blue). At my age, I don't want to spend a lot of time experimenting/researching the cause of things like this.

Thanks to everyone - all the responses are appreciated.

Edited By Bandersnatch on 24/08/2018 01:27:14

I have two rolls of abs that snaps every metre or so although the company i purchased it from did tell me about it and gave them to me for free with the rest of my order i can' t work out what did this to abs ? Maybe it is pla in the wrong box ??

I made a dry box up out of a plastic crate with a hinged lid , it has a foam seal and two of those rechargeable moisture control units you buy off eBay and some teflon tube to rout the filament to Hot end .

The last time i used the printer i left the pla in the teflon tube and it expanded then went brittle so i had to fiddle around fixing this before i could use the printer ( sat there for 2 months unused ) the pla in the dry box was fine and printed well once i got the printer back online .

Keeping your filament in a dry box does a couple of things :

It keeps it dry - filament will absorb moisture from the surrounding air

Keeps the UV rays off it .

Keeps it clean - dust is not a good thing and some run sponge wipers to ensure the filament is cleaan before it gets to the hot end .

Gives you somewhere to keep your filament neatly hidden away and my drybox holds half a dozen spools -all nice and dry ready for use - i used Neils roller stl file to print out some spool rollers that are mounted inside the drybox and this helps to control the filament very well indeed .

Boiling in water ? Never heard that one but maybe it possibly tempers the filament ? You would still have to bak it to dry it .

Filament cleaner - it's got some foam inside it. It bobs up and down when the filament retracts. The holes make sure it doesn't block the heatsink fins.