Fillament drying
Posted by Darathy
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Fillament drying May 19, 2015 06:01PM |
Hello i would like to know if the holes in the print are coused by something other then moisture ,this is brand new fillament i got recently and would be really disapointed that it would already be saturated when it arived 
And how do you guys dry it? ,i found putting it in the oven at 50C does improve but the spool bends in all directions making it a bit usless
and that was generaly a bad looking print lol ,i was printing too fast i think. but the holes happen even in low speeds.
Edited 2 time(s). Last edit at 05/19/2015 06:02PM by Darathy.
And how do you guys dry it? ,i found putting it in the oven at 50C does improve but the spool bends in all directions making it a bit usless
and that was generaly a bad looking print lol ,i was printing too fast i think. but the holes happen even in low speeds.
Edited 2 time(s). Last edit at 05/19/2015 06:02PM by Darathy.
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Re: Fillament drying May 20, 2015 12:39AM |
Looking at it, I'd agree that it is possibly moisture in the filament. Could possibly be something funky going on at the seams I suppose, a print with seams aligned would be a quick way to check.
But lets assume it's moisture for the moment.
First the oven:
In theory you're oven temp should be lower than the Tg of the filament. For PLA the Tg is '60-65C' on wikipedia --I'm assuming this is PLA because of your oven set point-- so you'd think 50C should be good. However, you're assuming the oven thermometer is accurate, if possible you might want to verify the oven temp with an oven thermometer if you have one or do the experiment I'll mention below.
Another thing to consider is where the oven's temperature sensor is (I'm assuming a modern digital oven is being used, but this probably applies to older ones as well).
- If the sensor is closer to the heating element it will read the 'max' oven temp, so no spot in the oven is hotter than this ever. Batch ovens in I've used in chemistry labs use this set up, because they are used to evaporate off flammable solvents i.e. acetone, MEK (methyl-ethyl-ketone), etc... you never ever want a spot in the oven higher then you set, least you exceed the flash point and cause an explosion. side note, these ovens are specially designed with all ignition sources i.e. electronics, heating elements, outside the oven, NEVER use a standard oven to dry off flammable solvents
- If the sensor is at the ovens exhaust it will read the 'min' oven temp, almost everywhere in the oven is hotter than this.
- If the sensor is somewhere in between, some spots in the oven are hotter and some are cooler. I suspect this is what consumer ovens do, because it would give an average temperature around the set point, which is good for cooking food at a predictable rate.
So, if your oven has a 10 or 15 degree variance from the sensor reading (assuming this is 100% accurate, which it probably isn't), you could unintentionally be at or exceed the Tg of the filament. On top of this ovens typically do bang-bang control, so the temp may cycle +/- 5 degrees during normal operation... and have some significant overshoot when you open and close the door. It's also possible a filament maker's pigments or other additives could alter the Tg, so 60C is really just a ballpark figure.
Also, If your oven has a 'convection' fan, turn it on.... this significantly reduces the temperature variation in the oven.
One way to find the temp to use is to do a small experiment.
I'd recommend cutting off small chunks of filament (verify it's circular to start off with! preferably with a caliper), maybe 5cm. Putting them on a pan with foil or parchment paper, and testing out various temperatures.... start at the 50C you're seeing problems at, maybe drop down 5 degrees at a time. You might want the duration of heating as long as possible. Maybe also put the pan as close to the heating elements on the bottom as possible.
Then check the filament to see if it's still round or has gone elliptical..... if it's deformed lower the temperature. You might still want to go a tad below whatever point you find to have a safety margin.
Now, I sadly have an oven with a minimum set point of ~90C or something.... so I can't dry my stuff in the oven.
I store my filament in a reasonably air tight container, and use these aluminum tins filled with silica gel (most filaments come vacuum sealed with a small silica gel packet, this is much larger). The gel turns from orange to green when it's saturated (well 60% saturated anyways), and you can throw it in the oven at 280F (so about 135-140C) for two hours to reset it. They're mostly marketed for keeping ammunition and guns from getting too humid I guess. It helped dry out some filament I was having trouble with. And it's fairly cheap
They supposedly protect 3 cubic feet each, but I just got 2 of them for a 2 cubic foot box. The more silica gel, the more moisture we can pull out of the filament and prevent any moisture getting in the box from going into the filament to a point (le chatelier principle of equilibrium, at work).
I got them on amazon for ~8USD each. [www.amazon.com]
Edited 5 time(s). Last edit at 05/20/2015 12:44AM by shadow651.
But lets assume it's moisture for the moment.
First the oven:
In theory you're oven temp should be lower than the Tg of the filament. For PLA the Tg is '60-65C' on wikipedia --I'm assuming this is PLA because of your oven set point-- so you'd think 50C should be good. However, you're assuming the oven thermometer is accurate, if possible you might want to verify the oven temp with an oven thermometer if you have one or do the experiment I'll mention below.
Another thing to consider is where the oven's temperature sensor is (I'm assuming a modern digital oven is being used, but this probably applies to older ones as well).
- If the sensor is closer to the heating element it will read the 'max' oven temp, so no spot in the oven is hotter than this ever. Batch ovens in I've used in chemistry labs use this set up, because they are used to evaporate off flammable solvents i.e. acetone, MEK (methyl-ethyl-ketone), etc... you never ever want a spot in the oven higher then you set, least you exceed the flash point and cause an explosion. side note, these ovens are specially designed with all ignition sources i.e. electronics, heating elements, outside the oven, NEVER use a standard oven to dry off flammable solvents
- If the sensor is at the ovens exhaust it will read the 'min' oven temp, almost everywhere in the oven is hotter than this.
- If the sensor is somewhere in between, some spots in the oven are hotter and some are cooler. I suspect this is what consumer ovens do, because it would give an average temperature around the set point, which is good for cooking food at a predictable rate.
So, if your oven has a 10 or 15 degree variance from the sensor reading (assuming this is 100% accurate, which it probably isn't), you could unintentionally be at or exceed the Tg of the filament. On top of this ovens typically do bang-bang control, so the temp may cycle +/- 5 degrees during normal operation... and have some significant overshoot when you open and close the door. It's also possible a filament maker's pigments or other additives could alter the Tg, so 60C is really just a ballpark figure.
Also, If your oven has a 'convection' fan, turn it on.... this significantly reduces the temperature variation in the oven.
One way to find the temp to use is to do a small experiment.
I'd recommend cutting off small chunks of filament (verify it's circular to start off with! preferably with a caliper), maybe 5cm. Putting them on a pan with foil or parchment paper, and testing out various temperatures.... start at the 50C you're seeing problems at, maybe drop down 5 degrees at a time. You might want the duration of heating as long as possible. Maybe also put the pan as close to the heating elements on the bottom as possible.
Then check the filament to see if it's still round or has gone elliptical..... if it's deformed lower the temperature. You might still want to go a tad below whatever point you find to have a safety margin.
Now, I sadly have an oven with a minimum set point of ~90C or something.... so I can't dry my stuff in the oven.
I store my filament in a reasonably air tight container, and use these aluminum tins filled with silica gel (most filaments come vacuum sealed with a small silica gel packet, this is much larger). The gel turns from orange to green when it's saturated (well 60% saturated anyways), and you can throw it in the oven at 280F (so about 135-140C) for two hours to reset it. They're mostly marketed for keeping ammunition and guns from getting too humid I guess. It helped dry out some filament I was having trouble with. And it's fairly cheap
They supposedly protect 3 cubic feet each, but I just got 2 of them for a 2 cubic foot box. The more silica gel, the more moisture we can pull out of the filament and prevent any moisture getting in the box from going into the filament to a point (le chatelier principle of equilibrium, at work).
I got them on amazon for ~8USD each. [www.amazon.com]
Edited 5 time(s). Last edit at 05/20/2015 12:44AM by shadow651.
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Re: Fillament drying May 20, 2015 03:05PM |
Thanks for the replays ,unfortinetly i have an over with setting of 50 and next is 75C , and its a really old oven XD(44 years old...) probably not really reliable. the fillament isnt the problem so far , the plastic spool deforms into a strange so i cant really mount it on the spoolholder .i will print a spoolees addon for [www.thingiverse.com] and just cut some out and put in at 50C and store the spool in the bag.
For storing fillament i got some vacuum bags and the silica gel.
The greenone is the newone i didnt test yet ,got a light blue one that the elfant was made from is saturated with water it just arrived and it wasnt sealed in Vacuum bag and didnt have any silica gel inside. it came from [3dfilaments.ie] ,i was so looking forward to it ,the test samples i got had such good properties ,shame they dont properly store the fillament
For storing fillament i got some vacuum bags and the silica gel.
The greenone is the newone i didnt test yet ,got a light blue one that the elfant was made from is saturated with water it just arrived and it wasnt sealed in Vacuum bag and didnt have any silica gel inside. it came from [3dfilaments.ie] ,i was so looking forward to it ,the test samples i got had such good properties ,shame they dont properly store the fillament
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Re: Fillament drying May 21, 2015 02:59PM |
This remix got a better trunk, the original one is a bit fragile
[www.thingiverse.com]
..and keep the bed temp. low and ad lots of cooling or you might end up with this mess:
..talk about mess, this is one of the reasons I gave up on slic3r, new version- new bug, this version went full retard with the 15% infill, sliced it right through, very sorry Ella, this is not worthy :-)
Erik
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Re: Fillament drying May 21, 2015 03:19PM |
I never had any problem with moist PLA but had one green spool of ABS, look real nasty when extruded from the hotend in free fall but printed just fine and did not have much visual effect on print - in fact, all the ABS parts for my ormerod 168 was printed with that spool
Looks like ET finger, phone home phone home...
But the prints was allright:
this is the worst I have seen, posted by another ormerodder long ago, you can actually see the water inside:
Erik
Looks like ET finger, phone home phone home...
But the prints was allright:
this is the worst I have seen, posted by another ormerodder long ago, you can actually see the water inside:
Erik
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Re: Fillament drying May 21, 2015 03:21PM |
put thatone in slic3r 1.2.6 and the trunk is missing a lot of its surface
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Re: Fillament drying May 22, 2015 03:37AM |
Quote
Darathy
put thatone in slic3r 1.2.6 and the trunk is missing a lot of its surface
Yes I can see that and a Netfabb repair did not help Slic3r but the original file sliced with Cura 15.04 looks just fine, so with this model, Cura seems to be the cure :-)
Erik
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Re: Fillament drying May 22, 2015 01:19PM |
i dont know if it is related somehow ,but i have a huge stringing problem
There are some holes in the sting starting point and there may be some relation to the holes in the elephant. i have tried recalibrating the extruder it did not work ,i lowered the temperature to 175 and still had stringing.
is there something else that would couse stringing?
There are some holes in the sting starting point and there may be some relation to the holes in the elephant. i have tried recalibrating the extruder it did not work ,i lowered the temperature to 175 and still had stringing.
is there something else that would couse stringing?
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