Weighing and Drying

[BONE]

Does any one weigh their filament before and after drying to calculate how much moisture was removed? Ideal, you probably want to weigh the filament with the spool reel.

[Jimustanguitar]

It would be interesting to do it in the opposite direction and weigh a spool that's new and known to be dry, and then let it take on moisture and weight it later.

[BONE]

Right. You could do it either way. There should be data sheets out there also, telling us what a certain volume of material should weigh. So lets say you have a 100 feet with known diameter, you should have a weight that you are shooting for before printing. You could use it for inspection when receiving material from a supplier also. Calculating and tracking weight of the filament will tell you a lot and another variable to control for better prints.

[teoman]

Then it would be advisable to measure the air humidity and then also calculate the archimedes lifting principle while weighing.

[BONE]

Then it would be advisable to measure the air humidity and then also calculate the archimedes lifting principle while weighing.

I think that's a little overkill engineering going on, but if you want to make us a spreadsheet, that be great!

[BONE]

Got roll of PLA from Gizmo Dorks yesterday and did a quick experiment. It seems to have lost a 2ozs of weight in about 4hours. I checked it each hour and I could see it slowing dropping also. I weighed the plastic bag and it did not affect the results. More official tests will have to be done later. I'm also questioning how much water could be in the spool reel itself also. Does anyone now what material the reels are made out of?

Filament was dried in a fruit dehydrator for 4 hours at 145F

After 4 hours

[teoman]

For us metric guys that was:

PLA lost 56 grams drying at 62 degrees during 4 hours.

And for the completely ignorant PLA spent an evening drying a a temperature very hot but touchable and lost a shot glass and a half of water.

So you are saying the pla was wet/moist when it came?

56 g is a significant amount of water.

[BONE]

This is my first spool of material and i still need to print something. The test was real quick and dirty. The battery died on my digital scale, so I had to use the kitchen scale. The test clearly needs to be repeated and I will do so in the future with a more rigorous test guideline in place. Weather the water came from the filament or the reel, it's water that is wanted near the filament. Maybe the dial moved on me and I didnt know it. But I do believe that I did get water of out the filament. More testing to come.

I would love for others to report results to increase the data points. I know drying works before processing, because my old job would dry every batch of material before going to the injectors. If there was an water in the pellets, it would turn to steam and generate problems. It will be the same thing coming out of the hot end on the printer.

[RocketMagnet]

I worked in an R&D lab and spent a couple of years in an analytical development lab.. yeah 20+ years ago now
in a previous life and different career but this is how I'd approach %LOD on this material.

Take a length - say 50g. Chop it up into small bits with some scissors wearing gloves so you don't contaminate it.
Your maximising the surface area to speed up the testing procedure (drying rate).

Weigh out 3X mass portions of the chips - dry each portion at desired temp until you get 3X successive constant masses on subsequent days for each.
then take the average of the three and you've got an accurate %LOD. If each individual %LOD is wildly different then something's gone wrong.
Main issue is you'll really need some dried weighing vessels (usually silica crucibles pre-dried repeatedly in an oven at say 150-200 deg C with proven constant mass).
It's quite laborious and time consuming to do LOD correctly as everything needs heated then placed in a desiccator to cool to room temp then weighed to constant weight . That's why the Sartorious & Mettler LOD machines exist to shortcut this procedure......

I'd say drying and weighing on the spool isn't accurate at all and not really worth doing...

The only comparison that's fair would be water take-up from total dryness minimum weight.. all in the same environment.

Ultimately I'd say long term storage in a sealed desiccator somewhere warm is the best option prior to use. A sealed container full
of indicating silica gel beads will be good enough IMO

[Generic Default]

We should test saturating it too. If I get an accurate lab scale in the near future I'll make a detailed report of filament water content and printing performance. Not just a general description, but I'd put accurate numbers to everything.

Nylon and polycarbonate are the high end filaments right now; both of them need to be dried to print.

Of course the end result is pretty easy. Dry it, put it in a sealed plastic tub or food container, then put a bunch of desiccant around it. Dry the desiccant too.

I made a thread a while ago about heating the filament on the printer by pulling it through a hot tube using the cold end as the puller. If we can get an airtight filament path from the filament container to the hotend, there will be no need for it. Right now my filament is only exposed to air during the time it is in the cold end. I'll make a sealed cold end extruder soon.

[BONE]

Of course the end result is pretty easy. Dry it, put it in a sealed plastic tub or food container, then put a bunch of desiccant around it. Dry the desiccant too.

Do you use any type of vacuum sealer after drying?

[RocketMagnet]

I'd presume when they extrude the filaments they lube the extruder head so potentially this lube could be retained on the surface and be driven off via heating and you'll count this as water when in reality it's not. So mass loss may not always be a good enough indicator as to water content. I've heard lubes and oils don't affect prints?

I'm new to this (still considering the Orion or the Max and if I can source in the UK.. importing's a ball ache) and I'm of the understanding that many people deliberately lube the filament prior to the head.
So with this in mind an oil seal system from the container would give you a 100% air tight with no messing around with physical septum caps (like the condiment
bottle tops used in another thread - they wont be 100%). Essentially imagine a "J" bend tube inside your container with the top of the J exiting out of the top of your dry container.. fill the bottom of the J with your lube oil and pass the filament out through this 100% oil seal (a lute like in a toilet). pass it between some sponges to wipe off the excess
and it's only air exposed for a short time after this.... I cant see it being that hygroscopic that it needs sealed continuously to the print head? just stored in a dry environment long enough prior to use.

I've seen the same principal used where mechanical seals are not deemed reliable enough and you absolutely must have physical access but absolutely must isolate the vessel atmosphere from the external atmosphere.. e.g. extremely toxic chemicals.

[Generic Default]

I think lubricant is only really used for printing with PLA, since PLA jams in the area just above the nozzle in hotends. ABS and nylon and other filaments don't need lubricant for printing.

If commercial filament extruders use a lot of lube on their nozzles, there will still only be a tiny amount that gets on any given length of filament since each spool is very, very long. I haven't received any greasy filament yet. They usually run the plastic through a water trough just after exiting the nozzle, which cools the plastic so it stays at the right diameter. This means all plastic is saturated from manufacturing. Nylon is intentionally saturated because wet nylon is much less stiff than dry nylon and stiff nylon breaks easier in trimmer line.

[RocketMagnet]

Ahh ok, only extruder I've seen in operation was an Aluminium one and I think I was 14 at the time but I recall it was
lubed a great deal. Very different here I agree and its quenched immediately then.

So presumably it's possible to form inclusions as you quench and no amount of low temp drying will help.
So looks like storing in a desiccator and finding a good supplier/manufacturer that simply works well is really what its about?

On second thoughts an oil seal may be a bad idea anyway as it may swell the plastic that sits in it longer term.

[BONE]

I think lubricant is only really used for printing with PLA, since PLA jams in the area just above the nozzle in hotends. ABS and nylon and other filaments don't need lubricant for printing.

I haven't heard of this. What kind of lubricant and where is it applied for printing? I've seen people clean there filament with a wiper before going in the extruder.

[Eaglezsoar]

I think lubricant is only really used for printing with PLA, since PLA jams in the area just above the nozzle in hotends. ABS and nylon and other filaments don't need lubricant for printing.

I haven't heard of this. What kind of lubricant and where is it applied for printing? I've seen people clean there filament with a wiper before going in the extruder.

See this link: http://forum.e3d-online.com/search.php?keywords=oil&fid[0]=13