3D printing post-processing process —— Annealing Treatment

Annealing is the thermal treatment of an object.

The process changes the structure of a material by heating it and then cooling it slowly.

The process was used in metallurgy to increase the ductility of metals firstly.

Today, the basic concept of annealing has been adopted for plastics.

The process of shaping metal objects often causes distortions in the crystal structures, called grains. The alignment of these grains can be modified by the rate at which the material is heated and cooled. When they are heated, they will return to their natural shape, and by adjusting the cooling rate, the grain size can be changed. Rapid cooling produces smaller particles, resulting in a harder but brittle material. On the other hand, when metal is cooled slowly, it becomes softer and more malleable.

Although the annealing process for plastics is similar, the end result is slightly different. As you know, a standard FDM 3D printer first heats the filament and fuses it, then the filament cools down at room temperature. This rapid cooling process adds stress to the object, shrinks at various points, and does not stabilize the molecular structure of the plastic.

Annealing 3D printing involves reheating a part to around its glass transition temperature, holding it near that temperature for a period of time, and then cooling it slowly.This easy method requires only an oven in the kitchen, making the prints stronger and more durable.