Some sort of hardware could be added that detects the moisture content of a filament and the appropriate retraction and wipe settings could be auto applied. Tired of strings! (and I hate waiting 8 hours to print something).
Though that would be nice, it sounds expensive.
I did see someone review one of these in-line dryers, that are meant to dry the filament before going into the printer. It was quite a bit ago and I don’t remember a lot about the outcome, except that they were not great. You could look into one of these and see for yourself.
If you can invent affordable hardware or methods that can directly measure moisture in filament, you will be rich. As far as I know, we can only infer the presence of moisture indirectly, by measuring relative humidity in the surrounding air or by monitoring weight loss while drying.
Yep! You absolutely can monitor water content in filament using humidity. In a sealed container with a hygrometer, you’ll get a humidity reading that is proportional to water content. The archival storage, museums, and desiccant manufacturers all use this to advantage.
We don’t have curves that relate moisture content to humidity but we don’t need them. The curves are set by physical characteristics of the filament and are constant. More humidity = more moisture. You can use humidity numbers the same way you would moisture contents. What you are really after is what humidity value is too high to print with. Get that and spools above that number need to be dried and those below it do not.
The way to test is with an impervious (or mostly impervious) container and a hygrometer. (No desiccant - it spoils the reading.) You can use a gallon ziplock but be aware if you leave it too long water can leak in. You just want a good reading after the hygrometer has stopped changing. Time is about 30 minutes to an hour but how quick hygrometers respond depends on a few factors. You just want the number to settle down unless it’s well above or below your go/no-go value.
Note that your own go/no-go values may depend on tuning you’ve done, etc.
The weight difference method simply does not work except in well-controlled conditions by those with good filament dryers. Since starting water content isn’t known by weighing, final water content after drying isn’t known either. A drying technique that isn’t very effective will see filament weight stop changing just the same as a good drying technique.
There is value in weight difference, though. If a drying technique is known to dry adequately, getting to no weight change means you are done and dry. It can be a quick and easy check. Also, if the magnitude of the weight difference is large, you have some confidence that you did a good job drying. Unfortunately there is fairly wet filament as well as fairly dry filament. A good drying technique won’t see a big weight change if you “dry” an already dry spool.
Weight difference as a check with a known good drying technique is fine. But if a drying technique is marginal and a user doesn’t realize that, a user can believe all their filament is dry (small weight difference) when it’s really not.
There are moisture meters available used with wood and drywall, etc. Some use radio frequencies and some conductivity. No idea which would even work with filament or how well though.
I bet there is a way though. It may not give accurate numbers but as long as the numbers change with moisture content, we don’t need to know the actual value. Something proportional to that actual value is fine as long as everyone understands the actual reading might be way off.
In that respect it’s a lot like using humidity instead of moisture content.
Not weighing in either way.
Just figured an alternate take might be interesting here.
The guy manages a filament manufacturer that creates some of the more interesting filaments out there for government contracts and such.
Have fun.
Wanna see some prints with a roll of PETG from that exact supplier that is absolutely causing garbage print quality because it’s moist?
I was thinking of the pin/drywall style measuring tools, but in this case it could be a pair of metal rollers the filament rolls through, similar to the extruder gears (but smooth) and resistance (capacitance?) is measured to determine moisture %. As you said, the exact value is less important than the proportional measurement.
That video keeps getting posted here but are people actually watching it? I ask that because it gets posted as a reply to legitimate drying discussions when it really doesn’t apply.
Mostly it’s an ad for the company’s filament without additives or fillers that they claim hold water.
As to dryers “lying to you”, they barely discuss drying at all instead falling back on “our filament doesn’t need drying”.
It’s really a commercial.
Exactly. Once you let go of needing an actual moisture value and understand something that tracks moisture level is just as good, it gets a lot easier.
So what if my meter (which I don’t have) says filament is 0.15% moisture? That number means nothing to me except in knowing if the moisture content is too high to print well or not. As a simple go/no-go though, it could be fine. Even if wildly inaccurate, as long as more water gets a bigger number and it’s repeatable, ease of use would make it a winner.
If I could hold a meter up next to a spool and get a reading in just a second instead of waiting 30 minutes for a hygrometer to settle, that would be handy!
Only thing is how transferrable it might be. Not knowing how accurate they might be with filament, if different technologies give different values you can’t compare between them without some kind of conversion factor. It gets cumbersome fast. A relative humidity measurement is directly comparable (as long as temperatures are the same).
Not really agreeing with the whole “commercial” slant.
It’s a video that speaks to how filament is manufactured and the reasons “why” we get the results we see when printing. It also addresses the variables of temperature, flow, etc. when working on reducing said variables. The gent is clear - he doesn’t advertise or reach out to the hobby community and doesn’t sell in the usual spaces. Why would anyone believe this was a “commercial”? He is clear that the company exists for government and special contracts. He DOES sell to the hobby community. But that is not at all where they put their resources.
The video is for informational purposes. Use it. Toss it. Ignore it. Agree with it. Disagree with it. It doesn’t matter to the gent. Nor would it matter to me. I placed the video here as a relevant point of discussion - we are discussing drying filament. The gent is stating the facts of whether or not it’s necessary for certain filaments. Pretty relevant.
Only thing is the video is kind of us vs them. They don’t use additives or fillers or use reduced amounts, but they are 3rd party filaments. Most here use at least some Bambu filaments. They sidestep the drying issue by showing condensation and saying “look at these terrible dryers” and that water collects in some of them. That’s basic dryers. They didn’t mention any of the helpers or even solutions. Mostly it was look at all the problems with other filaments and drying.
And nowhere did they explain the entire premise of the video if you assume a title should tell you what it’s about. How are dryers lying to us? There are legitimate discussions of where humidity and temperature are measured in a dryer where a dryer might be “lying”, but they don’t discuss that.
Anyway, you can watch the video as easy as I or anyone else can. It’s a commercial disguised as helping the community. It’s just promotion.
The YT account that made the video is looking for clicks. The actual interview with the gent is the reason I posted it. It offers a differing viewpoint. I am not going on record as to whether I agree with the gent or not. I’m merely offering up something to discuss beyond what’s out there. I use BL filament for the most part. Also use the Sunlu 4 slot dryer. I’m not living under a rock. You have your opinion and have stated it clearly. I don’t agree with much of it and have stated that. Probably should move on and allow others to enjoy the thread and take from any of this what they will.
For starters, the stuff I say about drying isn’t really opinion. It comes from reading the desiccant industry papers and articles and taking the time to document drying cycles then seeing how all that fit with the desiccant industry stuff. I welcome actual discussions of the technical aspects. If you can show me where I’m wrong and not just hand wave, I would love it. I’m not afraid of the actual truth behind it all and you shouldn’t be either. Show me my mistake. But do it with data.
Not sure if this helps, but I’ve been running welllll under 10% humidity and have never had an issue. I did recently change to a new dessicant. It’s a bit more money and doesn’t change color but holy cow, I am running at 0% humidity now. No joke.
I can’t upload photos for some reason but no joke.
maybe now that we have filament manager, if an ams had a scale inside it could it also track moisture content?
I’ve definitely had filament in a humid environment that foamed up coming out of the nozzle during a purge, and leaving it in a box with desiccant for a few days brought it back to life. I tried a heater-styler dryer, but now I’m just doing a sealed plastic box with desiccant.
I just got 15(?) rolls of Bambu PETG-basic, I’ll try putting them in the box one, two, four at a time and see how the humidity changes.
That is a common misconception. You cannot track moisture content by weight. You can only track changes in water content by weight but you can’t know the actual water content.
If you see a change, you at least have confidence you have removed water but without knowing starting water content you cannot know ending water content. You just know how much was lost.
If you see a small loss when drying, was the filament already dry or was the drying method ineffective? Weight can’t tell you, unfortunately.
Can’t you just overdry it as a reference? Snip off a sample, weigh, then bake it 80C in 0% RH, it’s as dry as it’s going to get. Doesn’t that tell you the absolute moisture content?
The only thing that would get measured is the exposed filament, it won’t tell you the internal moisture content of the filament not exposed to the air. You would need a deep probe that can make contact with the filament in the center. The AMS does tell you the moisture content of filament, to a degree, provided you are using desiccant. When you install fresh dry desiccant, and a roll of filament, close the box and come back, you will see the % drop. When it hits 0%, the desiccant has removed moisture from the surrounding air. Wait 24-48 hours and eventually the % will go back up as the filament releases moisture into the dry air, when then gets absorbed by the desiccant. When desiccant and filament reach equilibrium, then you know a close % of moisture in the filament.
Putting fresh dry desiccant into the AMS and 4 rolls, then put it through a dry cycle, watching the RH%, will also tell you how wet the filament is, to an extent. If you know the desiccant is dry, fill the box, seal it, wait 30 minutes for the air inside to stabilize, you should see RH% drop to single digit, then hit dry, RH% should climb up as moisture is released from the filament.
Desiccant removes moisture from the surrounding air, heating filament releases moisture into the air so the desiccant can remove it, so having fresh desiccant is a must or it will also release moisture as it heats up so you are chasing tails if you have spent desiccant.