Method and device for manufacturing a cutting insert green body

A method for manufacturing a cutting insert green body by compressing a powder, comprising the steps of

• providing a compression tool having an upper die and a lower die, an upper punch and a lower punch, wherein the upper die defines a punch tunnel in which the upper punch is arranged to slide, and the lower die defines a punch tunnel in which the lower punch is arranged to slide, and wherein the dies, when joined together define a die cavity provided to accommodate a powder to be compressed by action of the respective punches for the forming of said green body;
• providing the lower punch in a predetermined position in the punch tunnel of the lower die;
• filling powder into an open cavity defined in the lower die;
• joining the upper and lower dies such that an opening of the upper die meets and communicates with a corresponding opening of the lower die and such that said cavity filled with powder in the lower die forms part of said die cavity;
• compressing the powder in said die cavity by action of said punches, wherein said upper punch is forwarded through the punch tunnel of the upper die and is forwarded a predetermined distance L through said opening of the lower die and into the lower die, whereby said green body is formed;
• displacing the upper die relative the opening of the lower die, thereby providing for more space for the green body to exit through;
• and
• removing the upper punch from the lower die, and moving the green body out of the lower die through said opening of the lower die, wherein the die cavity defined by the dies has a vertical centre axis and that, in the region of said opening of the lower die, an inner peripheral surface of the lower die has an inclination angle α relative to said centre axis such that an inner circumference of the inner peripheral surface of the lower die increases towards said opening thereof, wherein the upper punch presents an abutment surface for abutment against the powder, an outer peripheral surface, and a punch edge at an intersection between the abutment surface and the outer peripheral surface, wherein the upper punch is forwarded the distance L into the lower die such that there is a remaining gap g between said inner peripheral surface of the lower die and said punch edge, wherein 0 μm<g≤30 μm, wherein the level of the punch edge will define an upper edge of the green body, and wherein the upper edge is formed where said inner peripheral surface intersects a plane of the abutment surface of the upper punch.