Manufacturing of ceramic parts by additive manufacturing technologies

Additive manufacturing, originally called "rapid prototyping", brings together innovative part manufacturing processes covering a wide range of applications. It is based on the principle of manufacturing parts by adding material, unlike all so-called "conventional" or "subtractive" processes, which produce parts by deforming or removing material.

Historically, additive manufacturing was developed to rapidly produce prototypes or mock-ups of objects in order to test their concept or design. It is now fully integrated into product design processes, and is all the more beneficial in that it reduces the risks associated with upstream project development, while keeping associated costs under control. In fact, it makes it relatively easy to produce parts whose geometry is identical to that of digital mock-up parts, without the need for an industrialization study.

Additive manufacturing can be referred to by many different names: 3D printing, layered manufacturing, prototyping. It is also often associated with the following terms: Rapid Manufacturing, Rapid Prototyping, Solid Freeform Fabrication (SFF) or Freeform Fabrication, Digital Fabrication, Automated Freeform Fabrication, 3D Printing, Solid Imaging, Layer-Based Manufacturing or Prototyping.

The fundamental principle of additive manufacturing is to distribute and consolidate the input material according to the geometry of the part. To achieve this, we had to solve the following four problems:

• accessibility: each elementary voxel of a part to be manufactured must be accessible at least once during the manufacturing cycle. The word "voxel" is a contraction of "VOlumetric pixEL". It is a 3D pixel used to represent an object in 3D space;

• the material: the material must become solid during distribution in the shortest possible time to minimize manufacturing time;

• topology: the entire volume of the part being manufactured must be described, unlike material removal processes where only the boundary surfaces are required;

• Precision: the amount of material to be deposited must be as small as possible, to suit all part and shape topologies. Geometrical precision comparable to that of material removal processes is required.

In order to exist, additive manufacturing has had to respond to these four problems, but above all it has had to improve the solutions in order to optimize its performance and become an industrial process that can be used for small series production.

This article provides a brief history, a description of the principle of additive manufacturing and the associated digital chain,...