What is annealing and why should I do it?

Annealing is most popularly known as a process used in Glass or Metal. This definition shows that: 

Anneal - to heat and then cool (a material, such as steel or glass) usually for softening and making less brittle

In the case of 3D-Fuel Workday PLA and Pro PLA, the annealing process is similar, but the result is to make the plastic stronger and more temperature resistant. 

Not all PLA can be annealed, however, it must have the proper additives included in it in order for this process to work. Workday PLA and Pro PLA have these additives as a part of their makeup as they come from NatureWorks™.  Attempting to anneal Standard PLA will result in a mess of plastic. Just saying.  

Annealing (Heat Treating) Instructions

To get the maximum strength out of your 3D printed part, we recommend a post- annealing (after the item is printed) procedure that can be done in your oven at a range of 176-266F (80 - 130C) to promote increased crystallization and further improve the heat deflection temperature.

For best results:

1. Preheat the oven or toaster oven.
2. Place your print on a room temperature baking sheet.
3. Place baking sheet with the item on it into oven/toaster oven.
4. Wait 30-60 minutes for annealing to complete
   (in order for the item to fully reach the temperature of the oven)
   1. You may see the print take on a milky/matte/opaque color transformation.
5. Turn the oven off.
6. Wait for oven to cool to room temperature before removing print.

Shrinkage and/or warping may occur. The degree of shrinkage/warping depends heavily on the part geometry. Items with extended sections can also be subject to some movement during this process. Only testing will show how any particular print will hold up. 

Some customers have tested a water bath annealing process using a sous vide cooker. This can ensure a more even distribution of heat but we recommend annealing for 60 minutes to ensure complete heat penetration.

Another variation on annealing is to encase the printed part in heated sand. This will help control or reduce any warping or shrinkage that can occur during annealing.

Results: Following this procedure will provide a stronger and more temperature resistant part. This will allow you to reach the full potential of the filament and printing process for your part.