Central to subtractive manufacturing is the use of advanced CAM software in combination with precise milling machines and tools. Depending on the material used, these tools can be made of hardened tool steel or even be diamond-coated. CAM software is responsible for positioning in the respective material and calculates the required milling paths for the machines. It therefore creates the link between the digital design and physical production. By using various tools - from burrs to grinders - the material around the desired component is removed by the machine automatically feeding the required tools during machining based on the calculated data.

Subtractive manufacturing at CADdent is characterized by a wide range of machinable materials, including cobalt-chrome, titanium, zirconia, glass and hybrid ceramics, polymers, PEEK and wax. Each material places different demands on the manufacturing process. For example, some materials require special tooling during the milling process - such as a burrs - or water cooling to prevent overheating and ensure the quality of the end product. In short, these specific requirements of the material influence the choice of tools and techniques used in the manufacturing process.

Despite the benefits such as smoother surfaces and lower material stresses, subtractive manufacturing faces challenges such as potential milling shadows - areas that a milling tool cannot reach – and due to the use of tools higher costs compared to other processes - such as additive manufacturing. At CADdent, these challenges are addressed through constant innovation and research in order to continuously improve the efficiency and quality of the processes.

Subtractive manufacturing offers significant advantages, which are particularly important in the dental sector:

In contrast to additive manufacturing, which usually requires several support structures, subtractive manufacturing only requires one or a few holding element(s). This simplifies the production process and minimizes the need for subsequent machining.

A striking feature of subtractive manufacturing is the creation of products with smooth surfaces - corresponding to the digital source data. This surface finish often reduces the need for further post-processing at various points, which saves time and costs.

Another advantage is the ability for parts manufactured subtractively from metal - for example cobalt-chrome or titanium - to be subject to significantly less or no thermal expansion and therefore no stresses during the milling process. This means that they do not have to be compensated for with complex stress relief processes, as is the case with the additive process. This leads to virtually consistent product quality and therefore reduces the process risk.

Subtractive manufacturing therefore avoids almost all internal stresses in the material, which is particularly important for precise dental work such as the production of large-span bridges and bars.

Due to these specific advantages, subtractive manufacturing is particularly recommended for the fabrication of abutments, bars and precise occlusal surfaces. The high precision and surface quality achieved with this process are of decisive importance for functionality and esthetics in these areas of application.