I have just tried the filament drying utility of the X1C (as I need higher temperatures than my Sunlu S1 can provide) and after some hours I checked to see if everything was going OK but I found an error message on the screen that said: “Drying failed”.
I don’t know what caused this, I have checked if there has been any issue with the grid the time it has been working but it’s not the case. I have read on reddit it’s a bug but I have not been able to find any bug report on this forum.
Also, I would like to point out something: there is no need to “prepare”/home the printer again after a drying session has been stopped or ended. I understand that if the steppers are turned off we should make sure nothing has moved, but also I believe this could be handled more efficiently as moving up and down the bed all the way takes some time AND we, as users, cannot forget to take the filament out to prevent it from colliding during homing. My intuition at least tells me to put it into drying again, almost forgot to take the spool out.
If you want to use your printer as a dryer, I recommend the following:
Lower build plate to the bottom
Insert filament spool standing up on its edges, not laying flat on the build plate
Manually turn on the build plate heater and set it for an appropriate temperature
Manually turn on the chamber fan
Go someplace else so you don’t have to listen to the fan drone for 12-24 hours
Come back and turn off the heater and fan, mount your spool, print
If you lay the spool flat, you have to worry about the filament on that side of the spool getting too hot. Standing on edge lets airflow under and around the spool and the filament should be heated more uniformly.
Remember that plastic is a good thermal insulator. On a full spool, it’s going to take a while for the plastic in the middle to get hot. And once it finally does get hot, you need to give it enough time to drive off its moisture content. IMO less than 12 hours on a full spool is too short for anything except vacuum drying.
If I want more than the 70ºC my Sunlu driers can reach, I use the procedure above with the build plate set at 100ºC. You can fit 4 spools inside the print chamber if you put them in edgewise instead of laying flat… and standing on edge, the hot build plate should not be able to actually “un-vitrify” the spooled up filament (which would cause it to get stuck to itself).
I have a vacuum pump for my vacuum forming station I was thinking about adapting to use for filament drying, too. Vacuum is really the most-optimal method for getting moisture out of filament (getting moisture out of just about anything, for that matter).
I’ve really been interested in investigating vacuum drying as well. Thinking about the process I’m assuming that you need to supply the driest air possible when you release the vacuum.
The filament doesn’t reabsorb moisture quite that quickly, there’s a “time constant” that’s going to be measured in hours at least, I think. Longer, depending on the filament and ambient humidity level. “Sponge” is not a perfect metaphor for what happens. Take a soaking wet sponge, suck the air out, drop it in a bucket of water, it immediately gets soaking wet again because water flows through it easily. But the process of moisture absorption in filament relies on “diffusion”, the gaseous water molecules have to force their way between the plastic molecules and that’s a much slower process.
