1 Topic by malek1979m

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Topic: Predrying PLA

Ok, so I've searched high and low and to my surprice I haven't really found enough information pertaining to pre-drying PLA. I read the article on http://www.plasticstoday.com, which gives you a general idea of what has to be done, but doesn't quite go into detail. And there isn't a wealth of information about it on this forum either. I've heard using some sort of oven set at a certain temperature, but this doesn't seem very convenient. Using a dehumidifier makes sense, but how do I go about setting this up? Do I put the pellets in a box and lay them in one large layer and stick the dehumidifier in there? How are you people doing it? And how long do I leave them to dry? and how do I know when they've reached 200 ppm or whatever the recommended amount is? And what's this about -40F dewpoint?! So many questions, so little answers!
Thanks so much in advance.

2 Reply by elmoret

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Re: Predrying PLA

Here's info from an actual user:

http://www.thingiverse.com/make:54818

The black is PLA with black colarant @ 150:1 ratio dried together in a presto cooker for 24 hours at 80C.

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3 Reply by malek1979m

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Re: Predrying PLA

Ok, so what is this presto cooker? Is this a pressure cooker or a slow cooker or what exactly is it? Can I get a model number and actual detailed instructions on how to go about doing it from someone? Can I pile the PLA pellets on top of each other or do I have to do 1 layer? I can't see doing 1 layer at a time to be possible. That would take decades.

4 Reply by Tomek

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Re: Predrying PLA

For my nylon filament:

I spent a while designing a small box and was going to add temperature controlled dehumidifier functionality with a microcontroller.

I made the box, and decided instead that I will just dump 250 grams of rechargable dessicant, and dry it out every time I replace the filament.   

But if you want to use a dehydrator they are not a bad idea but the pellets might stick a bit. Most dehydrate at 140 F, which is 60 celsius. PLA starts to get mushy.

5 Reply by Ralphxyz

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Re: Predrying PLA

Tim's reference above has "24 hours at 80C" (176 F).

Tomek, seems to think you will get mushy PLA dehydrated at 140 F, which is 60 celsius.

That is a big difference, a little confused and almost ready to setup my filastruder.

Ralph

6 Reply by elmoret

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Re: Predrying PLA

PLA's Tg is ~59C. It doesn't melt until higher, but becomes softer.

Also setting a heater to 80C doesn't mean the contents get to 80C.

Anyway try it both ways, PLA is cheap. Most crockpots don't even have temperature readouts anyway.

Filastruder - the robust, inexpensive filament extruder
E3Dv6 All Metal Hotend - the premier 3D printing hotend

7 Reply by Peoples-Exchange

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Re: Predrying PLA

I purchased the Presto 06300 Dehydro Electric Food Dehydrator on Amazon for $35. Walmart sells the same model online for $35 but watch out! it's $46 if you buy it in store at Walmart.

As stated above the dehydrator runs at 60°C (140°F). I dried my PLA from Filabot / Amazon for 24hrs without any problems. The pellets did not get mushy and I have thus far been able to extrude 1LB of usable filament. Removing the loose pellets from the dehydrator was the most difficult part. I personally stuffed the sides with paper towels to prevent any of the pellets from falling inside the dehydrator and then scooped the pellets into an airtight container with desiccants. So far so good!

8 Reply by elmoret

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Re: Predrying PLA

Why Filabot? OS Printing is cheaper!

Filastruder - the robust, inexpensive filament extruder
E3Dv6 All Metal Hotend - the premier 3D printing hotend

9 Reply by Peoples-Exchange

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Re: Predrying PLA

elmoret wrote:

Why Filabot? OS Printing is cheaper!

If your only ordering 1-2lbs Filabot is actually less expensive because of the free Amazon Prime shipping. I paid $14 for 2LBs shipped from Filabot where as from OSPrinting it would be $19.91.  In the future I will probably order the ~18LB bags from OS Printing which are definitely a great value!