Recently I was working on a prototype for DryBox for filament during printing.

(George Novtekov) #1

Recently I was working on a prototype for DryBox for filament during printing. I found a membrane element that can dehumidify the box only by using electric power, maintenance free with no noise and without reservoirs. The problem cam from the cost of the membrane as everything good it comes with something bad :).

So I would like kindly to ask you, would you spend 200$ for dry box if :

  • It is maintenance free
  • Only require electric power
  • Do not produce any waste or noise
  • Do not use heat and it is 100% fire safe
  • Will be able to operate 24/7 and you will be able to leave your filaments in it constantly as it will consume 3-5W only.
(George Novtekov) #2

Here is my prototype so far:

missing/deleted image from Google+

(Simon Risowkin) #3

I would buy a food dryer for $20 and put a rotating plate in it. Basically the same thing.

(Cameron Spiller) #4

@Simon_Risowkin yep that’s what I did.

(Ulrich Baer) #5

@Simon_Risowkin those working with heat, George proposes a SPE with a much lower power consumption which could be always on in a storage device.

(Florian Ford) #6

Is there a link to the membrane? Is this the same thing as Osmotic dehumidifier?

(Ulrich Baer) #7

@Florian_Ford looks like the RD4

(Peter Peters) #8

@Simon_Risowkin depends on the power consumption of the food dryer. 0.08 W per device is not that much for the RD version @George_Novtekov is using. Even if you use three of those.

And I believe he is intending to use it as a storage while printing. I don’t think that will work with the food dryer. Al though that is great for drying wet filament, instead of using an oven.

(Florian Ford) #9

@Ulrich_Baer Those look so High Tech … if one is getting that much value from his printer(S) then it could be justified… otherwise perhaps not. It’s a matter of money-in/money(value)-out

(Griffin Paquette) #10

$200 is far too much for consumer level. We print a lot of nylon at school (like many Kg a week) and even then we just keep it in a general monitored dry box

(Ryan Carlyle) #11

Have to weigh the convenience value and lifetime economics against something like calcium chloride desiccant (eg Damp-Rid.) I use polypropylene gasketed boxes (from Container Store) with a small tub of damp-rid and that keeps nylon dry for over a year. An M6 Bowden fitting and M6 nut provide an easy airtight penetration for a filament feed tube.

One downside to non-heater dehumidifier options is that they won’t initially dry PC and nylon. They can keep dried nylon dry but it’s very hard to pull out existing moisture without adding heat. The flimsy vacuum bag and ~20g silica packet the filament is delivered with does not guarantee the filament is dry when you get it. (PLA, ABS, and PETG can be dried with just desiccant or dry air though.)

(Simon Risowkin) #12

ATM I use ZERO power consumption dry box: IKEA container with lid and a fair amount of silica gel cat litter at the bottom :slight_smile:

(Smash Smashin) #13

I believe such dry box will be very useful to keep moisture sensitive filaments dry when a spool is printed for couple of months

(Jeff DeMaagd) #14

I might consider it. But even with the price at hand it seems too efficient to be true.

Edit: 0.084 g/day per device is probably the catch then. That seems pretty low, and it looks like you’re using 3 devices in your prototype meaning a quarter gram of water extracted per day. So of you have two spools with 1g of absorbed moisture each, plus the air you just let in opening the dryer to put the spools in, it could take a few days for it to get down to an appropriate level.

(George Novtekov) #15

This is the prototype and we will chage those 3 elements with one bigger capable of 2grams per day that should be plenty as vendor of the element suggest the new element is suitsble for volumes of 60 litres. The current prototype do not perform well under 40% Rh. With the new element we are targeting between 15 and 20% Rh for two spools in 2 - 4 hours after closing the lid. This was the reason of this vote. We realise that the current prototype is not effective enough and the new element is really expensive and will drive the price to 200$. Our original target was 100-120$ for one and two spools respectively. The new membrane is on its way to us and it should be 30 times more effective and will consume arround 1W in normal situation. So thanks everyone for votes.

(Ryan Carlyle) #16

If you do the math on nylon water absorption, I think you’ll need something like 20g+ water removed for initial drying of saturated filament. That’s just off the top of my head though, so haven’t done the math in a long time.

(Ulrich Baer) #17

@George_Novtekov any Idea about membrane degradation and lifetime?

(George Novtekov) #18

Vendor suggest that element got 5 year of lifespan in 24/7 operating state. If ne element is powerfull enough we wil be able to create cycle between 15 and 20% oh Rh that will increase the lifespan. And yes membrane degrade over the time and also if not handled properly.