The one proxy for quality that I had doubts about but which up to until recently worked pretty well for me was looking for filaments that the manufacture claims can print at 500-600m/sec. It worked pretty well for me up until I tried a double spool of Anycubic High Speed PLA from Amazon, which fresh out of the wrapper turned out to be the most waterlogged and worst filament I’ve ever tried. Even after drying 13g of moisture off a spool of the stuff, it turns out it was still only partially dry!
What I learned from that whole debacle was the importance of weighing the filament spool at multiple different times during drying, and logging it, so that I can review the trendline and know when it just won’t give up meaningfully more moisture even if I were to dry it a lot longer. It’s an exponential decay curve, and you have to dry until it fully asymptotes.
@lion7718 Any in particular you want to point me to? Looking down the list, he only seems to compare filaments within a particular brand, rather than do critical testing between brands. Or maybe I missed it?
What little I know of that reviewer is from looking at some of his filament dryer reviews in the past, and my take-away was that his reviews seemed a bit too charitable to the point of almost obviously not wanting to offend anyone too much, even with hard facts. I’d rather a reviewer looked harshly and critically with the purpose of weeding out the so-so products and ultimately identifying the absolute best of the best.
This brings to mind the first problem I faced when I started printing.
So very often the filament (from anywhere) has moisture in it and it affects quality as we all know. Too many times it gets diagnosed as something else and then more problems are created.
First thing people should look at. As you say, you can dry it for x amount of time and it STILL not be dry. So often I see posts where “I dried it for 2 hours” and it’s concluded that’s enough.
I just tried Siraya Techs TPU. Was utter ■■■■, and I dried it for 4 hours out of a sealed bag. Took nearly 12 hours before it was usable. Wish I had thought of weighing it.
Exactly right. That’s the trap I fell into. Since, up to that point in time, 13g was by far the most moisture I had ever extracted from any roll of fillament, my thought process was: “Well, surely it must be dry by now.” I had dried it for over a day in a Print Dry (which I’ve since learned, by measurement, doesn’t do particularly well at expelling moisture out of the drying chamber). How did I later discover that, despite 13g of moisture gone, it still was only partially dry? I was printing a 250mm diameter dome, and I got this rather interesting pattern of z-banding:
My first reaction was, WTF? Later I figured it must be the result of non-uniform drying of the filament on the spool, again possibly an artifact of Print Dry’s design, which likely doesn’t apply heat uniformly enough to the spool that’s being dried.
I generally start at 6 hours, unless it’s a particular filament that needs longer. My dryer (like most) has bearings to rotate the filament by hand to avoid as much inconsistency as possible, but I still get it.
If I had the power and intelligence to bestow any knowledge to the 3D printing world it would be “Dry it until you think it’s dry, then dry it some more.”
Interesting. I just printed an outer housing for a clock and got a uniform but random distribution of those little “defects” on the outer surface of the housing.
I knew it was a filament issue of some kind even though a brand new roll of basic black but it looks pretty nice - like it was intentional. It wasn’t though.
@MZip I see the resemblance. A good question to ask on a troubleshooting thread would be: what’s the full list of possible causes? In my case, it was so overt and extreme that I have no doubt as to the cause.
As I mentioned just very recently on a different thread, every filament I’ve tested has moisture in it, even fresh out of the wrapper, no matter who manufactured or vended it. None of them are bone dry. This is no real surprise because, AFAIK, they all go through a water bath to cool down after extrusion and prior to winding. So, whether it’s a problem or not depends on how much moisture is in it, not on whether there is some or there’s none.
I don’t know of any reliable quick test for knowing how much is too much. Most likely it differs from one filament type or brand to the next. I’m tired of the uncertainty, so I’m adopting a scorched earth policy of drying everything to bone dry prior to printing and maintaining bone dry during printing. Well, attempting to, because getting to real bone dry is another level that’s easier said than done. Still, “It’s the only way to be sure,” and so that’s what I’m gearing up for. I really don’t care that some people claim to have no problems after a couple hours in their lousy filament dryer, or no dryer, or fresh out of the wrapper, or whatever. I used to believe that too, and by careful data collection I’ve since convinced myself that some of that was luck.
I tried that once and hated it! I prefer the smooth look.
I have been playing with scarf seams and they appear better, but not perfect. They do add time to print unfortunately, so the priority needs to be weighed with them.
Good advice and your post had me remembering your other posts about weight and drying and asymptotically getting lighter. At least I think those were yours. And I had no idea they cooled the filament in water. The roll in question was opened fresh from a very recently received 2-pack and immediately put in the AMS and used to print that part.
It turns out those were random seams and a setting I had actually set because I don’t like the line up the side of a print. I had forgotten I did that and it was the expected result of that setting. The expertise here is amazing!
But your point is still very good. It wasn’t the filament this time but easily could have been. It could have been the issue I had with the shiny black filament that was brittle and printed poorly compared to the black Basic PLA that has a semi-satin finish to it.
I guess I need a good digital scale now to monitor drying even of new filament if it doesn’t print well out of the gate.
Thanks for the reply and still very good info. Turns out this was my fault and an old brain ain’t helping.
It’s maybe only appropriate for some things. It’s actually a fairly cool effect if you want it and it can also add a little grip. But absolutely - not a choice for all things!
Cheers!
And my name change happened! Thanks again, @JonRaymond!
Just ordered my own filament dryer and thanks for all the information. I’m halfway tempted to get a digital scale to put it on so can monitor weight loss as it dries.
@MZip It would be nice if there were a way to leave the dryer on a scale (load cell) and get the weight automoatically plotted over time as it dries. My scale says not to leave any weights on it but to remove them after weighing–otherwise accuracy suffers. If it were only a small loss of accuracy though, it would be worth it.
Not sure if other scales would allow for continuous, grams measurement accurate to, say, tenths of a gram? Anybody know?
More good information. Maybe there’s some that don’t take a set? Will keep an eye out for that though if I feel the need to go that far. It’s not easy looking for little changes on a big tare weight. Can also just take the spool out and weigh it like you were doing. I’ve got some little liquid paper displays for Raspberry Pis that would have made taring and graphing while drying almost fun.
Wow thanks for taking the time for that write up. Something to think about for sure. I’ve been using elegoo for awhile now and despite it appearing to be cheaper quality. It has worked fine for over 50kg so far for my purpose.
