Best moisture-free filament strategy?

[Cedric_K]

Quick question, how could you measure the moisture *inside* the filament? is it an easy way? (not the environment surrounding it, but the filament itself?)

Thanks!

To my knowledge, only a few professional devices can achieve that. I got one in my job, used to control that plastic pellets are really moisture-free (to prevent a drier fault). I don't know how much it costs, but that that it is very very expensive...

Just for information, here is a link to a device able to that : http://www.aboni.de/HydroTracer%20E.pdf

This is a test we have to perform on Nylon Injected Parts in my day job. Here we are intentionally adding water after molding to "temper" or increase the impact strength of the nylon for railroad tie pads for concrete ties.

To measure the sample is accurate weighted in it's wet condition then placed into an oven at 250F - 300F for three hours. After removal it is immediately weighted again and the moisture loss calculated.

Warning, part will usually not survive due to distortion.

Quick question, how could you measure the moisture *inside* the filament? is it an easy way? (not the environment surrounding it, but the filament itself?)

Thanks!

As you said, destructive method.. Makes sense, but not sure it could be useful for a printer filament : you need a good weight if you want a sensible result, destructing several hundred grams of very very expensive filaments to control moisture... Useless according to me..

In most of the case, we have standart times and temps for each material... if dried according to theses value, no problem.

As I understand, the idea of lowering pressure in a vacuum chamber, is to get the water boiling point down to around 40 C /100 F (at ~1 PSI), which, besides of being more convenient, will reduce the possible damage (by heat) to the filament, and, I guess, would also increase the amount of potential drying cycles. Does it make sense?

Thank you for you interest.. Your idea makes sense, yes, but I can't confirm that it will work.. Furthermore, if you encouter a moisture issue, you just have to put you filament to oven at the good temp and during the good time, you would not damage anything...

Just look at this datasheet, this is a standard document for each materials in plastic indutries, this is one material I work with in injection molding, Look, there is a section dedicated to drying... This is a common thing you have to do, to dry some plastic materials before transform them...

http://www.natureworksllc.com/~/media/T ... ms_pdf.pdf

[artexmg]

Thank you for you interest.. Your idea makes sense, yes, but I can't confirm that it will work.. Furthermore, if you encouter a moisture issue, you just have to put you filament to oven at the good temp and during the good time, you would not damage anything...

Just look at this datasheet, this is a standard document for each materials in plastic indutries, this is one material I work with in injection molding, Look, there is a section dedicated to drying... This is a common thing you have to do, to dry some plastic materials before transform them...

http://www.natureworksllc.com/~/media/T ... ms_pdf.pdf

Good info in the datasheet, thanks!

My concern about "possible damaging" the plastic is after drying it several times. I think I read somebody mentioning that drying the same Nylon filament for more than 4 times could get the plastic "stressed". Without any fact to support this, I think it sounds logic that a cycle of drying-hydrating-drying would have some effect on the plastic properties.

I know, the key would be, after getting out of the oven, to put it into a airtight container, to prevent the filament to regain moisture. BTW, Cope (I think?) calculated the amount of water needed for the filament to get saturated, and concluded that a small container would do the trick as the volume of air inside would not have enough water regardless the RH in the environment.

The problem with is once you get the filament out of the container for, say, a 8 hours print, as it would start to regain moist.

The solution I had seen, is to print with the filament inside a container, making a "small, sailed aperture" in the container. There are some examples over here, in the forum.

HOWEVER, I do not know how effective an airtight container *with a hole*, would be to prevent moist to be absorbed after 8 hours. This is why I would like to have a method to test the moisture within the filament, not just the HR in inside the container. I really would like to know for sure.

Nice device the one you pointed out, by the way! (and yes, it looks expensive!!)

Thanks!

[Cedric_K]

I think no one of these ideas would give a really good result, but they are ideas, and it's important to begin with ideas.

I only give my opinion as a plastics technician, but I can be wrong, I have not tested to prove it can't work.

Thanks to you, I had a (no so good) idea, too.

Imagine a printer which is totally close and a bit heated (I will not speak there about the interest of printing in a heated closed volume, but it would increase a lot most of printings, that's why professional printers are always enclosed...)

If your spool is in this closed heated volume, it will keep dry a lot longer... time to finish a 20hour print easily...

2 Issues :

-It's difficult to make an enclosed box for a printer and to control temp inside, but it could be made...

-Electronics and steppers of our reprap-like printers are not designed to be heat-resistant. it will suffer a lot... but it can be insulated much more easily with a delta printer than with a cartesian one.


But honestly, I don't think that a lot of cycles drying/moisturing/drying/moisturing can damage any material if time and temps are respected. Made a lot of times with plastics and never encoutered issues. In an other hand, I saw damaged nylon because of too much drying time (2days...). The material after these 2 days was weird, and impossible to work -> dust bin.

[artexmg]

Thanks to you, I had a (no so good) idea !

I think the best way to prevent moisture recovery, is to work in a printer which is totally close and a bit heated (I will not speak there about the interest of printing in a closed volume, but it would increase a lot most of printings...)

If your spool is in this closed heated volume, it will keep dry longer... time to finish a 20h print easily...

Issues : It's difficult to make an enclosed box for a printer and to control temp inside...
Electronics of our reprap-like printers are not designed to be heat-resistant


But honestly, I don't think that a lot of cycles drying/moisturing/drying/moisturing can damage any material if time and temps are respected. Made a lot of time with plastics and never encoutered issues. In an other hand, I saw damaged nylon because of too much drying time (2days...). The material after these 2 days was weird, and impossible to work -> dust bin.

Humm ... while it could be a little cumbersome to have the Rostock Max in a airtight, heated chamber, I certainly could add some heat element to the "semi-air thigh" container (the typical Tupperware) with the filament inside.

Then, if needed, I could re-cooked with the confidence that several cycles will not damage my filament.

Sounds like a good "Moisture Management System" to me, a comprehensive and doable (and cheap!) one