Drying Out Filament

[Joe Soap]

I am aware from previous comments made that filament which has absorbed
moisture needs to be put into a heated oven to get rid of the moisture.

I am in the process of building a sealed chamber which has a
dehumidifier. Heat won't be part of the equation. If saturated filament
was put into this chamber, would it be reasonable to expect it would
release the moisture?

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[Ryan Carlyle]

Slowly, yes. It's a two-way equilibrium. But the hotter you go, the faster it will dry and the dryer you can get it.

[Joe Soap]

I am intending to build a sealed chamber under the 2X (I bought a desk
especially for the 2X so this fits in). It will have a dropdown door for
loading filament, and the feed will go thru 6mm tube - so not completely
sealed but as close as possible.

With the filament nested in that box it can take as long as it likes to
dry out. Or not get wet in the first place.

I found these on ebay and figured I would give them a go:

http://www.ebay.co.uk/itm/230865372518

Good reports from people who have used them. However not from the 3D
printer community.

On 07/07/2014 16:08, Ryan Carlyle wrote:
> Slowly, yes. It's a two-way equilibrium. But the hotter you go, the faster it will dry and the dryer you can get it.
>

[Enginwiz]

This is a plastic box with predried silica gel and a heater to dry it again, after the wet indicator changes its color.

I use a simmilar method for keeping ABS and Nylon filament dry inside transparent ZIPLOC bags.
The challenge is, that silica gel only absorbs water up to low percentage of its own weight.
So you need a lot of silica gel to dry out a whole spool of filament. Or you have to change
out the silica gel frequently and regenerate it by heat. And you have to be patient.

Currently I use 50 Gramm packs of silica gel with a yellow humidity indicator. The indicator
changes color from yellow to a dark green when the silica gel is fully loaded with water.
I have two packs of silica gel in every ZIPLOC bag with filament. Every two or
three weeks I check the color of the silica gel packs in the ZIPLOC bags and replace
green wet silica gel packs with yellow dry silica gel packs. After a number of exchanges
the silica gel packs in the filament storage ZIPLOC bags stay yellow and the filament stays dry.

The green wet silica gel packs get dried in the hot air kitchen oven. After one hour
at 110 degrees Celsius the indicator turns back from green to yellow and the silica gel is dry again.
Half a dozen of still hot silica gel packs get stored in a small ZIPLOC bag. In these bags the
Silica gel packs stay yellow / dry for more than three month.

If I buy new filament I predry the new roll of filament in the hot air oven for two hours.
PLA gets dried at 50 degrees Celsius, ABS and Nylon at 80 degrees Celsius.
The still hot roll of filament is stored together with two silica gel packs in
a ZIPLOC storage bag and the silica gel only has to absorb the last bit of remaining
moisture out of the predried filament. This jumpstarts the whole drying process.

During printing the dry roll of filament sits on a spool roller inside a ZIPLOC bag
together with some packs of silica gel. The filament exits through a small
opening in the ZIPLOC and directly enters the 6 mm hose to the extruder.
This keeps the roll of filament dry during printing and protects it from dust.
The silica gel packs have to be exchanged twice a week to stay dry / yellow.

[Ryan Carlyle]

I think I'm just going to buy a whole-house dehumidifier and stop worrying about it.

[Joe Soap]

It sounds like we are on the same page. My intention is to keep filament
in ziplocked plastic bags with silica gel, and any 'live' spools feeding
the bot would be hanging on a rod in a sealed chamber under the machine.
That chamber will have at least one of these packs, which could be
swapped quickly.

[tunell]

I think the easiest solution is just to move out here to arizona.

[Ryan Carlyle]

Houston is pretty dry most of the year. We run the AC nonstop anyway. It's really just my wife leaving the patio door open that kills the filament.

[Joe Soap]

Yeah, right. I've been to the USA twice but I doubt I will ever go again (health and age issues now). But thanks for the invite.

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[TinyBot]

Sounds cool but just curious about a few factors. Your spool will be in a enclosed cabinet. (Checked) The Makerbot sits on it (checked) but wont you still have a part of filament that (If you dont unload) will be sitting out between the cabinet feeding into the bot? Wont that absorb moisture and result in at least 1 meter or so of humidity soaked filament?

[Scott D]

Well I guess that will depend on how often you print. I dint remove my spool every day when I'm done unless I know I'm not going to print for the weekend. Even with AC running constantly my house is at 40% to 50% humidity and I haven't seen a roll get affected. If you printing every day to every other day I dint see the meter of filament being affected unless your under water.

On Tuesday, July 8, 2014 4:10:34 AM UTC-4, TinyBot wrote:
> Sounds cool but just curious about a few factors. Your spool will be in a enclosed cabinet. (Checked) The Makerbot sits on it (checked) but wont you still have a part of filament that (If you dont unload) will be sitting out between the cabinet feeding into the bot? Wont that absorb moisture and result in at least 1 meter or so of humidity soaked filament?
>
> On Tuesday, July 8, 2014 10:40:28 AM UTC+8, Joe Soap wrote:
>
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>
> Yeah, right. I've been to the USA twice but I doubt I will ever go
> again (health and age issues now). But thanks for the invite.
>
>
>
>
> On 07/07/2014 21:51, tunell wrote:
>
>
>
>
> I think the easiest solution is just to move out
> here to arizona.
>
>
>
> On Monday, July 7, 2014 1:21:43 PM UTC-7, Ryan Carlyle wrote:
> I think
> I'm just going to buy a whole-house dehumidifier and stop
> worrying about it.
>
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[Joe Soap]

On 10/07/2014 11:58, Scott wrote:
> Nothing, I now owe you. And ecolodges os on your purse with $46.00
>
> Thank you,
> Scott
>
>> On Jul 9, 2014, at 8:14 PM, Joe Soap <joe.s...@gmail.com> wrote:
>>
>> I'm in the UK and have been monitoring humidity, I'm seeing mid-40's.
>>
>> I recently started trying to use bridge nylon. After a couple of days I
>> started noticing small spurts of steam coming out the nozzle, and that
>> was what drew my interest to managing the humidity level.

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[Joe Soap]

I haven't actually built anything yet - I'm currently acquiring the
parts I need.

I found the following on ebay this morning, and it looks to be just the
ticket for building the chamber I'm after:

http://www.ebay.co.uk/itm/261449997628

Cheap and cheerful, but that's fine.

Hopefully it will give me 4 decent sides which will butt together
without me having to do major woodwork surgery. I can then add a plywood
back (for rigidity), and hinged perspex front. Providing I can seal all
the edges then I'm hopeful that will do the job.

The dehumidifiers arrived this morning:

http://www.ebay.co.uk/itm/230865372518

[Enginwiz]

This is the ZIPLOC version of a sealed filament cartridge with silica gel packs.

A short piece of M30 treaded rod and two hexagon nuts add 1 kg of weight and keep a nearly empty spool down on the ball bearings.

The yellow/orange indicator in the silica gel packs turns blue/green when the silica gel is loaded with humidity.

Checking the humidity status is easy: As long as the silica gel packs are yellow/orange the filament is dry. Otherwise the silica gel packs have to be replaced.

[Drew in Sunny Florida]

Time for another dumb question on drying :  Has anybody tried microwave heating to drive off the water in the plastic ???  I presume it would also drive off some plasticizer but it may be that a few minutes in the microwave can clear the water before it ruins the filament.  

[Jimc]

i dont know about that one. you want to heat up filament slow and evenly. microwaves make hot spots. i wouldnt do it.

[Joseph Chiu]

PLA will begin creeping at around 60C... Microwaved water will heat up quickly, and even if it doesn't heat up the PLA to 60C globally, it seems likely that it can create tiny pockets that might turn the filament into Swiss cheese?

[Andrew Aurigema]

I was thinking Bridge Nylon but you do make a good point for the lower temp plastics. 

Well if heating the plastic and driving off the water is a bad idea ....... what about a large room temperature desiccant chamber ???  Living in Florida I would need the chamber to  have an actual de-humidifier tied to it and a drain for the water.  I am thinking of a chamber that is tied to an actual dehumidifying machine.  Something large enough to put in a bunch of rolls and keep them dry all the time.  It may take a day or two to dry out a roll of plastic just having it in very low RH air, but if you stored the plastic in low RH air it should not re-contaminate with moisture.  

It may be an extreme solution but what if the whole printer were in a cabinet that was flooded with dry air.  The spools could be stored in the cabinet ( on open shelves ) and the printer would not have to be unloaded at the end of each printing session.  All the printing materials would be maintained dry so they are ready for whatever the use is at printing time.  Again, it is an extreme solution but maybe required for this new technology.     

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[Enginwiz]

Having the printer and the filament in a closed chamber with an active electrical dehumidifier and a heater would be the best, but most expensive solution in a very humid climate. Full airconditioned printer - 3D printing turns into a luxury.

[Ryan Carlyle]

Yes, you could put all the filament in a "reverse humidor." That would work. (I've been considering a small peltier chiller to condense out water from my filament box instead of using Eva-Dry-333s.) It would be very slow at drying wet filament though. For a very rough rule of thumb, the rate of drying doubles for each 10C temp rise. 

[David Yu]

Microvave even at the lowest setting is too strong and too fast. I tried it and my filaments got ruined. 

Better to use traditional heat source like an electric oven. Cook it slower and not too hot. I do it at 80 - 100 degrees . 

[Enginwiz]

100 degrees Celsius is above the glass transition point of PLA and ABS.
This is too hot. Your filament and probably the spools might get deformed.

Drying filament at low temperatures is better. I have been looking for an
electical food drier recently, but couldn't find one with a proper temperature
controller and a big enough hood for my filament spools here in Europe.

Does anybody already use a food drier for drying filament?

[Guidozelf]

Hi Joe,

This is what I did to store my filament dry and ready for direct use, without tangles and without hassling with spools during filament changes...

May be some it can be of use for your solution.

http://www.thingiverse.com/thing:399284

Cheers, Guido

[Enginwiz]

Nice printer workstation!

What humidity level do you get in the filament cabinet
if the small peltier dehumidifier is running?

[Guidozelf]

Thanks, the unit is advertised as suitable for closed spaces of up to 15m2.

It's able to remove about 250ml under ideal circumstances in 24 hours.

I've only acquired it recently, looks like it's reducing the humidity level by at least 15%  compared to the outside of my cabinet - although levels do  fluctuate with the environment ...

[Joe Soap]

Forgive me if I am in error, but I got the impression that the drying cabinet you constructed wasn't sealed? As you have doors which open I was thinking when I saw the photo's on thingiverse that there would be air gaps around those doors. If that is the case then getting the moisture content down might not be easy.

Also, I wondered whether having the dehumidifier and its tank inside the controlled environment might add to the problem.

My chamber is reasonably (but not perfectly) sealed, and I am currently working on the dehumidifier being outside of the chamber. Basically I'm putting one of these outside with a fan:

http://www.ebay.co.uk/itm/230865372518

The air circuit into and out of the chamber will be sealed, so that the air circulating around the filament will be more or less separate from the outside air. As these units are rechargeable I'm making a small box unit with a lid so that they can be exchanged easily - without having to open the master chamber.

I've no idea how well this might work - however in recent days I put one of those units into a large sealed plastic box with NO fan, with a hygrometer which I could read from the outside, and within 24 hours it got down to 11% RH - with an ambient 50%+ outside the box (we've had storms in the UK this week so the environmental RH is up a bit on normal). I'm kinda hopeful that once I've completed my filament chamber I can maintain RH below 20%.

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[Guidozelf]

You're right: my cabinet is not airtight: there are gaps around the doors (small, and one could add a post for the doors to close against) and  I have a gap at the back, where my cables run through (which could be closed as well).

I'm not convinced it's a big deal if the cabinet is not airtight, since the unit will work 24h to extract moisture, the heater is there to have a good operating temp for the peltier based device.

Still experimenting here, look forward to learn how you fare!

Cheers, Guido

[Joe Soap]

It's coming along. The main chamber is in place, feeding filament. I'm currently printing the bolt-on box which will do the dehumidifying. I hadn't thought of a heater, so I hope you won't mind if I end up nicking that idea (I see this going in the external dehumidifier box rather than taking up room within the chamber).

What I could really do with is a dehumidifier switch, which will turn the fan on if the humidity is too high. I don't see why the fan has to run 24/7 if the humidity is down to the level I'm looking for. However finding such a switch seems impossible - I may have to resort to a small arduino project for that.

[Scott]

Have you checked cigar box accessories. Seems like someone would have made something like this already that you could adapt? 

Thank you,

Scott

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[Joe Soap]

I have spent the last few days investigating the use of  a silica gel package within a filament chamber slung underneath my 2X. Results so far disappointing, but I have ideas to further this work.

Firstly, no amount of effort would persuade the relative humidity of the filament chamber to decrease by any appreciable amount. There might be a couple of reasons for this. Firstly, I didn't air-seal the chamber and so there would have been very small gaps around the edges. However the more likely explanation could be that this was a largely wooden chamber where I hadn't sealed the surfaces. It wouldn't surprise me if that environment led to humidity leaking out of the wood panels - either through the woods own moisture level, or perhaps some microscopic action making the wood porous to the outside world. Either way, this was not a good solution.

However on a parallel path I bought a big plastic box, into which I put half a dozen partly used filament spools (one being the nylon bridge filament which had absorbed moisture). Although not perfectly sealed I put a silica gel box and a hygrometer which I can view from the outside in there. As soon as the box was closed, over a period of 48 hours I watched the RH descend - and for the last 48 hours it has maintained an RH of 10%.

I am therefore minded to build me a plastic version of my wooden filament chamber, which will be pretty much sealed. I intend to put a drawer into this design where I can swap out the silica gel box as needed, without fully opening the chamber - for the few seconds where this drawer is opened it won't appreciably alter the chamber environment. Changing the filament or feeding it to the printer will obviously open the environment to the outside world - however I don't think that will cause a major problem for the silica gel box, it will raise the RH for a short time but I'm sure it will descend quickly as already measured. If this works out then I will be feeding my printer with filament coming from a low RH environment.

This is going to take me a little while so I'm not going to provide a running commentary.

[Scott]

Joe, if you want to keep the wood look have you tired to seal the inside panned with a water sealant and silicone caulking on the corner joints? 

Scott

To live life in a fog or high is to miss life's natural beauty and every day miracles that are in front of you. 

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[Scott]

Joe, I know we both have been searching for a good solution. This is what I came up with so far.

I have the waterproof toolbox for storage for the filament when not in use, and using a few Eva dry 333 and the RH averages 20. 

I printed a taulman spool holder from the gingers and used nylon for the bottom bars so the one side can bend in slightly and a copper pipe for the top bar for a smooth rolling action. This now fits inside a sealed ammo case and keeps averaged 20 for the RH using one Eva dry 333 in the ammo case. This is now used for the 1kg nylon spools. I drilled a whole for the filament tube, and created a plug for the whole when I'm not printing from automotive silicone gasket maker. I had to cut some of the plastic supports in the lid out for the tube.

For the 2KG spool as you know I tired the Platto big orange box, but it turned out the walls are to thin to create a good seal on the rubber gasket and couldn't get it below 44 RH and my air conditioned house sits at 50 so that got returned. 

I remembered about the filament safe, the first one I tried months ago the rollers wouldn't move causing friction when the spool rotated, but decided to give it another chance. This one I bought has a smooth rolling action, but the task to overcome was a way to remove the moisture when loading the safe with a new roll.

I ended up buying 1LB of color changing rechargeable desiccant from amazon for $40 US, and also got 25 cotton bags 4"X5" with draw strings to make my own desiccant bags. With one ladle full each bag averages about 80 grams. With the loose desiccant I was able to out a layer in the bottom of the filament safe. With in the first 30 minutes it dropped from 35 RH to 15 RH. I'll report back after 24 to 48 hours to see how low it goes. I'm using this to dry out my nylon currently. 

I may also put my shelve back I the tool box and just lay about 500 grams of desiccant loosely on the shelf and see if I can get the toolbox lower than 20. Originally months ago I bought this little metal box with 40 grams of color changing rechargeable desiccant. They say to recharge it in the oven, but I could not justify turning in my oven for this little box, I found if I out this under my HBP while printing ABS it drys out good.

Now with the loose desiccant I'm thinking  I can dry 1/2 LB at a time in a cookie sheet in the oven and then store it back into a sealed container until needed while the other half is doing it's job keeping my filaments dry. 

I've included some pictures for the different things I have going not in,coding the tool box since I've posted that in the past. 

 

Thank you,

Scott

To live life in a fog or high is to miss life's natural beauty and every day miracles that are in front of you. 

[Enginwiz]

Scott: Your filament dry box looks great! Would you be willing to post your design on Thingiverse?

I am still printing out of the poor man's sealed filament cartridge - a 330 mm x 380 mm Ziploc bag.

So far this works very well. I have four silica gel packs inside the bag. The filament spool rides

on top of 8 ball bearings on an adjustable spool roller.

To get some data on the humidity level inside the bag I added a

DHT22 (or AM2302) humidity sensor and wired it to a Arduino Uno.

Adafruit sells this sensor with a small breakout board  and published

a library together with an example sketch. I removed the readings for

farenheit and heat index to make the terminal messages easier to read.

During the last days the weather was mostly rainy and humitity levels in the office were around 60 % rH.

Inside the filament bag the relative humidity in the air stayed around 15 % rH like in your filament box.

Most of the cheap humidity monitors measure only between 20% and 90% humidity.

The DHT22 (or AM2302) offers the full range between 0% and 100% rH and costs only US$ 5.

Accuracy is +/- 3%. More accurate humidity sensors seem to cost a little fortune.

[Scott]

Regretfully this is not my design, it was originally a kickstarter and now being sold on their site or a local Microcenter if you live by one? 

http://www.perceptioneng.com/index.php/products

Looking at it I would say if you can cut plexiglass you could make one. I was able to make something for the small rolls but I was not ahoy with things I tried when looking for a sealed container for the big rolls. So I just bought this one.

Because of were the whole is I do find that I have to set the safe vertically in the back of the printer for it to feed smooth, or removed the filament tubing from the back to route it correctly to the safe if you place it behind horizontally and I have to move the printer out further from the wall.  I'll probably buy a longer filament tube sometime. 

I did print some small parts last night and it worked good, I'll have to print a big part first to see how it goes and make sure it has proper tension on the roll and does not bind the filament by unrolling to easy. 

Thank you,

Scott

To live life in a fog or high is to miss life's natural beauty and every day miracles that are in front of you. 

[Joe Soap]

Thanks for that. However I've been drilling holes in my current chamber
and frankly it's in need of a replacement. Using a sealant to coat the
inside has crossed my mind - but sadly too late in the process.

On 27/07/2014 07:28, Scott wrote:
> Joe, if you want to keep the wood look have you tired to seal the inside
> panned with a water sealant and silicone caulking on the corner joints?
>
> Scott
>
> To live life in a fog or high is to miss life's natural beauty and every
> day miracles that are in front of you.
>
> On Jul 26, 2014, at 2:42 PM, Joe Soap <joe.s...@gmail.com

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[Dave Young]

I like your ideas - where do you get the silica gel packs?

Dave

On Monday, July 7, 2014 4:17:05 PM UTC-4, Enginwiz wrote:

This is a plastic box with predried silica gel and a heater to dry it again, after the wet indicator changes its color.

I use a simmilar method for keeping ABS and Nylon filament dry inside transparent ZIPLOC bags.
The challenge is, that silica gel only absorbs water up to low percentage of its own weight.
So you need a lot of silica gel to dry out a whole spool of filament. Or you have to change
out the silica gel frequently and regenerate it by heat. And you have to be patient.

Currently I use 50 Gramm packs of silica gel with a yellow humidity indicator. The indicator
changes color from yellow to a dark green when the silica gel is fully loaded with water.
I have two packs of silica gel in every ZIPLOC bag with filament. Every two or
three weeks I check the color of the silica gel packs in the ZIPLOC bags and replace
green wet silica gel packs with yellow dry silica gel packs. After a number of exchanges
the silica gel packs in the filament storage ZIPLOC bags stay yellow and the filament stays dry.

The green wet silica gel packs get dried in the hot air kitchen oven. After one hour
at 110 degrees Celsius the indicator turns back from green to yellow and the silica gel is dry again.
Half a dozen of still hot silica gel packs get stored in a small ZIPLOC bag. In these bags the
Silica gel packs stay yellow / dry for more than three month.

If I buy new filament I predry the new roll of filament in the hot air oven for two hours.
PLA gets dried at 50 degrees Celsius, ABS and Nylon at 80 degrees Celsius.
The still hot roll of filament is stored together with two silica gel packs in
a ZIPLOC storage bag and the silica gel only has to absorb the last bit of remaining
moisture out of the predried filament. This jumpstarts the whole drying process.

During printing the dry roll of filament sits on a spool roller inside a ZIPLOC bag
together with some packs of silica gel. The filament exits through a small
opening in the ZIPLOC and directly enters the 6 mm hose to the extruder.
This keeps the roll of filament dry during printing and protects it from dust.
The silica gel packs have to be exchanged twice a week to stay dry / yellow.

[Andrew Aurigema]

You can dry silica gel in the microwave oven also.  It is scary how fast it starts steaming and changing color to the desiccated state.  

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[Big-E]

Humidity hasn't been much of an issue for me until lately; It's been especially hot and humid this summer. My printers are in my basement office, so I rarely have issues. Still, this year, I've had a couple humidity problems, so I recently added a solution.

I purchased a gigantic storage tub. In it, I place (almost) all my spools. If possible I store them in their plastic bags with silica packets.
in addition to this, I have a Damp-rid moisture absorber for RV use in the tub with the filament; These things work great! If you only open the tub to remove or replace filament, it works best.

If I intend to use a color over the course of the week, it's on my filament rack, or on the machine. otherwise, it goes into the tub to dry it out a bit. it seems to resolve my issues.

[Andrew Aurigema]

Thinking of only storing a few of the spools under desiccant.  Went shopping online (Wa-Mart) and found plastic 10"x11"x6" see thru dog food containers with air tight seal.  Then found 9" diameter plastic turn table.  Total cost per storage box will be about $20.  I am thinking one spool of filament per box.  My plan is to put an inch of descant on the bottom of the container, then a printed separator, then set the turn table on the separator ( above the descant), then set the spool of filament its side for the unwind out the side of the container.  I plan on printing up a simple 90 deg elbow assembly that will go thru the container wall and feed the filament up ( or down ) to the printer.  I really think whatever container is used needs to have some kind of roller bearing ( even if only plastic ball bearings in a plastic ring ) to cut down the sliding friction of a full spool of filament resting on the supports.  Going sideways is a cheap option as the turn table is only $8 each.   Pics of the finished setup to follow if it all works.

  

[Enginwiz]

I bought the silica gel packs on Amazon.
Some sellers also call them Dry Packs.

The silica gel with the color changing
humidity indicator is my favourite.
One look and I know wether the
silica gel and the filament in the bag
are wet or dry.

[Enginwiz]

These silica gel packs are simmilar to the ones I use in my filament bags.

http://www.amazon.com/Dry-Packs-10gm-Indicating-Silica-Packet/dp/B00967J7UM/ref=pd_cp_p_2

[MrScottJD]

Just an FYI, you can do it cheaper for a lot more...
In my previous post I out that I bought 1lb of loose color changing desiccant. That was a typo, the link to amazon is for 1 Gallon of color changing desiccant..
Given that the entire container & contents are listed at 7.7 pounds, the contents should be about 7 pounds, the can and top appear to be plastic. This leaves 3225 grams apx. (7 pounds) for the gallon of product.

That's more than what others are selling for 10gram packs, I think it was $169 for 40 10 gram packs. With the 1 gallon you can buy the little cotton bags for a few more Dillard and make your own, or use it loose in the bottom of a container. Just an idea. If I had found this 1 gallon container for $40 in the past I would have never bought the Eva dry 333 I own since each one costs $20 and I'm sire my oven will dry it our faster than the Eva dry heating element.

Maybe share the cost with another local 3D printer person?

1 gallon desiccant color changing
www.amazon.com/gp/product/B00BXJ52GO/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

Bags I use for 80 gram packs, you can get these much smaller if you want.
http://www.amazon.com/gp/product/B00GW622IO/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

[Scott]

Andrew, i like the idea and just wanted to share some thoughts i had on it. 

I have that same container but mine is a little taller. It also claimed to be air tight. But I know mine is defiantly not, the lid is so loose on the top,the clamp does not clamp it down that good. Just letting you know because that one looks identical to mine and probably made my the same company. If this is a in store item I would look at it first in person. 

You may need to add a little to tension on the turn table. If it rolls to easy it's possible that the spring like tension of the filament may cause the turn table to spin, in turn causing the roll to un-coil and get the filament tangled while printing. 

Thank you,

Scott

On Jul 28, 2014, at 2:56 PM, Andrew Aurigema <eosr...@gmail.com> wrote:

Thinking of only storing a few of the spools under desiccant.  Went shopping online (Wa-Mart) and found plastic 10"x11"x6" see thru dog food containers with air tight seal.  Then found 9" diameter plastic turn table.  Total cost per storage box will be about $20.  I am thinking one spool of filament per box.  My plan is to put an inch of descant on the bottom of the container, then a printed separator, then set the turn table on the separator ( above the descant), then set the spool of filament its side for the unwind out the side of the container.  I plan on printing up a simple 90 deg elbow assembly that will go thru the container wall and feed the filament up ( or down ) to the printer.  I really think whatever container is used needs to have some kind of roller bearing ( even if only plastic ball bearings in a plastic ring ) to cut down the sliding friction of a full spool of filament resting on the supports.  Going sideways is a cheap option as the turn table is only $8 each.   Pics of the finished setup to follow if it all works.

<box.jpg><turn table.jpg>  

[Scott]

I wanted to update the RH levels in the filament safe after 24 hours. I originally had the nylon in it, but then out a roll of ABS that was having issue printing in the safe for 24 hours, it prints much better now after being dried out. I had left this roll on the back of the printer for a few days and forgot to remove it and out it back in the toolbox.
The ABS had a RH level of 2% after 24 hours..

Then I out the nylon back in and it went down to 3% RH after 24 hours. The safe defiantly seals, maybe a little to good. I think their may be a point when you dry out the filament to much. I think I read something about filament being to dry is also not good for it or printing with it. My toolboxes always kept it at around 20 and was almost perfect so I'm going to add a little more desiccant now that I have the loose kind to the tool box. I'm thinking a safe number may be between 10% and 15%. So for the safe I'll inky use it for drying out damp rolls and printing from it but will not keep filament inside while plugged for long periods of time.

Maybe if I pull out the plug it will achieve the number I'm looking for?

[Enginwiz]

The Ziploc on my bag has two small openings to let the humidity sensor wires in and the filament out.
With four small silica gel packs the relative humidity in the Ziploc bag stays between 12% and 15%.
The black SmartABS in the bag prints perfectly at this humidity level. No hissing, no bubbles and
no stringing.

Currently I print some custom designed fixtures for IOtech DAQ equipment, that is used for vibration testing.
These fixtures are solid blocks of ABS printed with 100% infill. No cracks, no delamination with the dry filament.

[Andrew Aurigema]

Scott ( and all )

Turns out we have the bigger containers also for the dog's chow :_)))   

I see they are not really air tight also.  But that is easy to fix as a bit of self adhesive weather stripping foam ( 1/2" wide x 1/4" high ) will more than close up that gap.  I am not worried about the lack of tension on the turn table.  The filament guide should have a bit of tension in it from the curve.  I have not printed it out yet but as I now design with 3D printing in mind I have been very successful with the builds.  I attached a picutre of the part but am not sure if they are getting thru.  I will try attaching the picture and not just embedding it.  

 

[Scott]

Nice design. Yes the picture was in the post.
Is that going to be a 5/8 whole needed for the threaded side to feed through the wall the container?
Will this be something available in thingiverse once you're tested it?

[Andrew Aurigema]

It is 1.0 in hole.  Big and easy to install was my thought.  Had not thought anybody would want it but if so then sure.  It was a fun design and is printing now.

Sent via the Samsung Galaxy Note® II, an AT&T 4G LTE smartphone

[Andrew Aurigema]

Here is the v1.0 printed filament guide and the digital v2.0 drawing.  The threads were a little tight so I opened up the tolerance by 5 mills on both sets.  They worked but I don't want to have to fight with the nut when it is installed on the thin wall container.  I added a brace because the support material was massive for the overhang so I might as well have structure if something has to be there anyway.  I messed up and printed at 75% infill and this thing is nearly solid.  I am backing down to 10% infill because it is stupid overbuilt now.  All my pup food containers and turn tables are due in tomorrow so should be desiccating filament by the weekend.  The ability to control the placement of the supports and vary the infill by height is pretty sweet.  I am really liking Simplify 3D.  Getting the raft right is challenging but the program is very good.       

[Enginwiz]

Nice filament guide! Díd you print it with ABS or PLA?

Check out that you don't get too much friction in the elbow.

The available pulling force is quite limited on Makerbots direct drive extruders.

If you get air prints with the filament guide you might need to increase the radius of the elbow.

[Scott]

+1 enginwiz

I was thinking the same thing. Is e diameter of he elbow the same all the way through it?
If it was maybe 45 then the tube could feed into the whole part eliminating any friction on the filament since the filament would feed in the PTFE tube at way?

[Andrew Aurigema]

Thanks for the idea.  I made the feed tube hole large enough for the teflon tube to be fed up inside and thru it.  Now there will be a single tube from the container to the melt head.  That is a long way for air to migrate and it will keep the filament dry all the way down to the feed roller.  It even looks cooler :_))))) 

[Ryan Carlyle]

So, bending force is one thing -- PLA can't be safely pulled through a tight radius, period. It will break. ABS maybe, depending on the radius. Nylon is no problem.

But once you get to a certain radius where filament bending force is negligible, radius doesn't matter anymore. The necessary outlet force to overcome drag is a function of: 

• the coefficient of friction 
  
• the swept arc of the turn 
  
• the back-tension on the spool side
  

Radius of curvature literally does not appear in the equation. (http://en.wikipedia.org/wiki/Capstan_equation) A larger radius spreads a smaller contact force over a larger contact length. This is analogous to the fact that regular 2D friction force is not dependent on surface area, only normal force and coefficient of friction.

[Ryan Carlyle]

*** With the caveat that tight turns may cause sufficient contact pressure to cause wear on the inside corner of the guide tube. In an extreme case, you can dig a rut into the wall of the guide and get "keyseating" binding when the diameter changes. Bigger radius will reduce wear rate. 

We deal with this sort of thing a lot in the oil industry.

[Drew in Sunny Florida]

I am printing this out of ABS.  I am hoping this will not happen with the low loads the teflon guide tube will experience.  I really cant feel any any drag difference when pulling the filament thru the factory layout or my new layout.  The teflon tube is the same length in both ( about 20" of tubing).  

I have attached the v2.0 of my filament guide.  At 10% infill it printed in less than an hour.  Will get it up on thingverse if I can figure out how :_)))))))