This device does the same thing as putting your filament in a vacuum chamber. I did both with 585 inches of 1.75mm Nylon and the results were the same. It removed .025oz. of water by weight. That’s a lot of pimples and blisters. The filament comes out bone dry.

For those that aren’t familiar with the effects of vacuum on water view the chart image below.









So what would it cost to get set up to eliminate the moisture problem?

Our device will sell for $60.00 to start. Once we start wholesaling that may go up. Additional cost will vary depending on how you want to run it. View the Water Vacuum Chart Image and think about it. You could run 29+ inches of vacuum and do it without any heat. You could run 240f and do it without vacuum. (you would need to change the extension tube to high heat plastic)

From the beginning of this project I chose 140f and 28” of vacuum as the goal. That gives a good buffer to make sure the filament gets bone dry. (view the chart again) I’m very familiar with both drawing a vacuum and supplying heat as we use it in multiple areas from casting aluminum to degassing resins to infusing woods.

140f is an easy to temp deal with. 28” Vacuum is an easy vacuum to draw.

The Vacuum / Heat method will run approximately:
- Our Device - $60.00
- 100 watt Heat Band - $8.00 - $17.00
- K Type Bare End Thermocouple - $6.00
- PID Controller - $24.00
- Solid State Relay - $8.00
- Vacuum Pump - $160.00
- Vacuum Tank - $37.00
- Vacuum Contoller - $30.00
- Misc Tubing, Fittings, Switches and Gauges – $60.00

So . . . about $400.00 total. You could save a lot by sourcing the vacuum components. Don’t underestimate the value of having a solid vacuum source in your shop.

Will be posting component sources on the site. Web Site will be up soon and revise this with link when it’s done.

Edited 4 time(s). Last edit at 06/23/2014 07:19PM by OpenNRG.

Ineresting project, but there is a cost benefit ratio to be considered. If this where applied to PLA or ABS, if you use cheap $20 chinese filament as opposed to higher quality, say $40 filament, it would take 20 rolls of filament to recoup your losses.

Yes, this may be overkill for some. The target is more the production shops or those individuals that really value their time and are tired of sticking their filament in an oven.

It also depends on how you use or plan on using your printer. I look at everything from a production view. My main go to plastic is nylon because of its durability and dye ability. You can extrude it natural and just dye it whatever color you need.

Another of my go to plastics is polycarbonate. Polycarbonate absorbs moisture like a sponge. The bullet proof nature of polycarbonate is partly due to the high moisture content it contains.

If nylon absorbs relative humidity in 24 hours then it seems to me it would be pretty labor intensive trying to keep it dry in an oven or desiccant container. What happens when you start a day of production with dry filament and by 2:00 in the afternoon you start seeing a degradation in the print quality?

My goal was to be able to start my machine in the morning, turn it off at night, and start it again the next morning or if needed just let it keep running 24/7 stopping only to change spools. The thought of constantly dealing with and watching for moisture seemed impractical.

Most of the expense is the vacuum system. The prices quoted are for a good vacuum system using all new components. This is relatively high volume / high vacuum system.

All this device actually needs is a low volume / high vacuum system. The bleed through to release the steam is extremely small. You can build or even print a vacuum pump capable of reaching 28” of vacuum. You can even convert $20.00 air compressors to vacuum pumps. If it doesn’t reach 28” of vacuum then just bump up the temperature. (The tubing extension we ship with it is vinyl with a working temp of 175f) A small storage tank for buffer can be made from 4” PVC and end caps.

This device can be mounted by the head or a few feet away from the head. If mounted a few feet away then just write a startup routine that feeds that few feet through the dryer to the head so you start off with dry filament.

Decided to do a test with just heat and new device. No Vacuum. Results were identical. This may be a better way to go. Could be controlled with an Arduino or PID.

Cost with no Vacuum, just Heat:

Heat only Dryer - Probably $40.00
100w Heat Band - $8.00 to $17.00
Relay - $8.00
PID Controller (optional) - $24.00

Total would be - $56.00 to $89.00 depending on choices.

The heater seems to kick on for about 10 seconds every few minutes so watt hour use would probably be somehwere around 20. Will get more accuarate on that tomorrow.

The filament coming out is too hot to touch for more than about 20 seconds but within a couple of inches it has cooled back to ambient. That's at a feed rate of 4ipm.

Will post some images and numbers tomorrow.

Are you running it at 28inches and 140F in the pic?

Duh. It says so in your text....

Edited 1 time(s). Last edit at 06/23/2014 07:55PM by DaveX.

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OpenNRG
- K Type Bare End Thermocouple - $6.00
- PID Controller - $24.00
- Solid State Relay - $8.00

This all comes to about $20. [www.ebay.com]

Interesting. Just doing a bit of digging on ebay I found this heater for $7.51 [www.ebay.com]

And these controllers can go up to 194f (can be bought in C if desired) for only $14 and they can hande 10 amps with no external solid state relay. I use this type already for other machines, they are easy to set up. [www.ebay.com]

I have a stupid question. Can the filament vacuum seal that you are using be used as an outlet on a vacuum chamber? I am thinking about something along the lines of Werner Berry's Harbor Freight vacuum drying chamber, but storing the filament under vacuum and letting it out as it is being fed into the extruder:

https://www.youtube.com/watch?v=iGNXHWPFAKo#t=541

Thanks for all the info OpenNRG, this is very helpfull

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[www.hackerspace-ffm.de]

Quote
vreihen
I have a stupid question. Can the filament vacuum seal that you are using be used as an outlet on a vacuum chamber? I am thinking about something along the lines of Werner Berry's Harbor Freight vacuum drying chamber, but storing the filament under vacuum and letting it out as it is being fed into the extruder:

https://www.youtube.com/watch?v=iGNXHWPFAKo#t=541

Yes it can. I considered that method along with several others. I chose the inline method because it's the most compact and least labor intensive. Once installed, your done with it. Just pass the filament through it on the way to the print head. With the sealed version (vacuum assisted) that takes maybe 20 seconds. With the open version (heat only) it may add 1 second to routing the filament.

Working on final design for both Heat and Vacuum Assisted models. Will post again when done.