Most Nylon (PA) based filaments, especially PA6 and less so PA12, are very hydroscopic and printing them after storing in a dry box for even short periods of time result can result in a bad print (stringing and rough surfaces). I always move my PA filament from the dry box to the drier and dry for at least 6hrs at 80C before attempting a print. For short prints (under a few hours) I've found it sufficient to transfer to a dry box and print from the box. After a few days or longer it goes back into the dryer before a print.
A common mistake people make is that a dry box is enough to prevent wet filament issues for Nylon. Even in 10% relative humidity (which is typical of a dry box), PA6 nylon filament can absorb enough moisture to affect print quality within as little as two days. Therefore, the purpose of the dry box is not to keep the filament dry enough to print, but to lessen the amount of time it needs to spend in the drier. Nylon can also absorb a significant amount of moisture from the air if left exposed in as little as 4 hrs.
For example, a roll of Siraya Tech PPA that was dried for 8hrs at 80C was placed in a dry box at a constant 10% RH for 1 week. A test object was printed immediately after removing from the dry box. As you can see there is a very rough surface, stringing and blobs which are indicative of wet filament.
The same filament was then dried for 8hrs at 80C and printed immediately after removing it from the drier. As you can see there is a drastic improvement in print quality with smooth layers and no stringing.
Comments
█
█
█
█
█
█
█
█
█
█