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Dry Filament

Dry filament prints better than wet filament. New, fresh out of the bag filament is not necessarily dry. You can get brand new filament and it can be wet.

All plastics absorb water. The only difference is how fast and how much. PLA will absorb water slowly and TPU will absorb water quicker.

When you print wet filament the water gets heated to over 200c. It turns to steam. It changes the pressure inside the nozzle and you can get puffs of steam or blobs of filament.

You need to dry filament. There are lots of ways, some better than others.

You can stick it in the oven. I would not eat stuff cooked in an oven that has been used to dry filament. Most ovens do not have the fine control over temperature at low values. Set the oven to 50c, for PLA, and the oven might get up to 65c and melt the filament you are trying to dry. Ovens are big and they usually have some air flow, so the moisture can get out. However, because of the eating and por temperature control I would never use an oven.

Some people use dehydrators. If I used one to dry filament I would not use it to dehydrate food. They can keep a constant low temperature and they do get the moist air out. The major drawback is that they are not designed to hold a 1Kg roll of filament. Generally you have to take a dremel to the dehydrator to make filament fit.

At least one printer says you can put a roll of filament on the bed, cover it with a cardboard box, and dry the filament. Great temperature control. Some, but not the best, air movement. You can’t print while drying. Its not the best. It is the cheapest.

A sealed box with desiccant. As water comes out of the filament it is absorbed by the desiccant. The problem is the water comes out slowly. It can take months to dry a roll of filament. After you have dried filament, in some other way, this is great for keeping the filament dry.

A filament dryer. It’s made to dry filament. There is a problem with some that do not have air movement. Water comes out of the filament but it stays in the dryer. After the inside of the dryer gets wet water comes out of the filament slower. When you turn off the heat the filament is in a real humid box and it starts to reabsorb the water. A good dryer will have some airflow. As the air absorbs water it gets blown out of the dryer and fresh, dry air comes in. They are great at low temps. They usually have timers. Many will let you print right from the dryer for plastic that absorbs water quickly.

This will tell you more about drying filament.