Using heated bed to dry filament  

RE: Using heated bed to dry filament

Posted by: @towlerg

I wonder if its possible to use the heated bed to dry filament?

If the printer is placed in an enclosure and you reach the required temperature/filament, this is theoretically possible. But I think that this will only work well with PLA and PVA, maybe also TPU.

RE: Using heated bed to dry filament

You can make a drying cabinet really cheap. I bought an inexpensive food dehydrator. I didn't want to cut up the original trays, so I bought a 5 gallon work bucket for another $4. I then printed the  CAP_BRACE.STL from http://www.thingiverse.com/thing:1618037   This allows me to slightly suspend the inverted bucket off the bottom of the dryer. The dryer has a nice temperature dial on it. This holds at least 3 spools. It works very well.

RE: Using heated bed to dry filament

I would use a low temp electric oven, preheated and stabilized to the drying temperature.

RE: Using heated bed to dry filament

@gerrykaslowski

Did you ever measure the temperatures you receive, when you put it for example to 65 °C? I have the same food dryer as in your link and mine had a very big histeresis in temperature. That was the reason why I used a small Arduino, an electronical relais for switching current, a poti for temperature selection a small display and a digital temperature sensor. This helped to get the temperature close to the selected value (about +/- 1°C).

Before changing temperature control I destroyed one spool of filament by too high temperature.

Best regards, Clemens

RE: Using heated bed to dry filament

I use this one https://weckenonline.com/dejelin-nutridry-nd500s-voedseldroger.html
You can attach/detach the middle of each tray adhoc, extra trays are available

Greetings,
Yveske

RE: Using heated bed to dry filament

RE: Using heated bed to dry filament

Posted by: @clemens-m

@gerrykaslowski

Did you ever measure the temperatures you receive, when you put it for example to 65 °C? I have the same food dryer as in your link and mine had a very big histeresis in temperature. That was the reason why I used a small Arduino, an electronical relais for switching current, a poti for temperature selection a small display and a digital temperature sensor. This helped to get the temperature close to the selected value (about +/- 1°C).
 

Before changing temperature control I destroyed one spool of filament by too high temperature.

Best regards, Clemens

I hit it with may laser thermometer a few times and it was reasonable. I wasn't concerned. I kept the temps pretty conservative.

RE: Using heated bed to dry filament

@karl-herbert

Hi

what is the source of the drying time/temps you posted?

RE: Using heated bed to dry filament

Thanks for the input, but nobody addressed the original question.

On the subject of food dryers, what process is used to ensure the the exhaust air is not just replaced by more wet air?

RE: Using heated bed to dry filament

@towlerg

Just placing it on the heated printing plate is not sufficient. You need a closed installation space with stable and accurate temperatures.
I can't remember the source of the drying temp. It is already about 2 years old. These are only rough approximate values and can deviate somewhat with the large number of filaments. But I would rather use a lower temperature for a longer drying time than a too high drying temp.

RE: Using heated bed to dry filament

@towlerg

I also use it to dry coloured silica gel. If left in the open the silica gel turns pure black, after taking a ride in the food dryer it returns to its light orange state without a problem. So I wouldn't worry about the capabilities of the food dryer

RE: Using heated bed to dry filament

@yveske

Thanks for your input.

"So I wouldn't worry about the capabilities of the food dryer" I'm not concerned, I just want to know by what process they work.

RE: Using heated bed to dry filament

"Just placing it on the heated printing plate is not sufficient" hard to say till I know how they work.

"...with stable and accurate temperatures." I rather suspect that my printers heated bed has those properties.

RE: Using heated bed to dry filament

Quick Google

"There's the same amount of moisture, but the relative humidity of the heated air is much less —the warmed air can “hold” a good deal more moisture than the cool air. ... It's just that, at higher temperatures, water molecules are more likely to go into the vapor phase, so there will be more water vapor in the air."

So the warm air escapes at the top of the food dehydrator and takes with it the moisture it collected from within your filament.

RE: Using heated bed to dry filament

https://all3dp.com/2/how-to-dry-filament-pla-abs-and-nylon/   ideally vacuum-sealed after drying.

RE: Using heated bed to dry filament

@yveske

"So the warm air escapes at the top of the food dehydrator and takes with it the moisture it collected from within your filament." So with the addition of a cover with suitable vents my idea should work. I guess the principle problem is getting room temp/humidity air into the cover without heating it too much.

RE: Using heated bed to dry filament

@towlerg

Yes it should more or less. I don't know how fast the build plate will heat up the cold air before it starts rising.
It will be a fun experiment, but don't know how cost effective (money, build time and drying time) it will be compared to a real food dehydrator.

Have fun,
Yveske

RE: Using heated bed to dry filament

I was thinking about this too recently. Only one way to find out.
My oven wont go this low on its lowest setting, and I am not willing to spend more money on a dehydrator.

My thinking was, the spools fit perfectly on the heated bed. Place a nicely cut box out and place it over it trapping the heat in. Leave it for a few hours and see how well it does.

Challenge accepted!

RE: Using heated bed to dry filament

I converted one my dry boxes to a makeshift dehydrator using some laying-around parts.  Easy and cheap.

However, and ironically, shortly after I did this, we got a new kitchen tool/toy, the Ninja Cooker, which has a dehydrate mode, so lately I've been using that.