Breviary Technical Ceramics


      From Powder to Part




4.1.6 Machining

As shown in figure 62, green machining (after drying), white machining (after burning out and prefiring) and hard machining (after sintering) are to be distinguished.

Figure 62: Classification of green, white and hard machining in the production process

Green machining

is performed on the dry parts while they still contain organic additives. It is well suited to the manufacture of individual parts and small series. It is also used with large series to manufacture shapes that cannot be realised directly by initial forming procedure, such as holes transverse to the direction of dry pressing.

Figures 63 and 64: Components being machined green

White machining

is performed on the prefired parts, now free from organic additives. The strength depends on the prefiring.
In this way, extremely high removal rates be achieved with relatively low tool wear using conventional, ceramic or diamond coated tools. This process is used by manufacturers both for making prototypes and for mass production.


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