The muffle (1) has cylindrical surface area, curved surface area (33) and outer contour that is convex with two truncated cone shaped bodies (32a, 32b) of different opening angles, where a portion of the cylindrical surface area around a muffle axis (A) lies below 10 percent with respect to the contour. The contour is flattened in an upper region and a lower region of the muffle. The contour is formed in right angle to the muffle axis. A socket (36) holds the muffle in a position during pressing process. Independent claims are also included for the following: (1) a device for manufacturing a muffle (2) a method for manufacturing of dental prostheses parts.
