Hard material insert with polycrystalline diamond layer

Abstract

A hard material insert ( 1 ) for a tool, which is configured segmental and has a planar, polycrystalline diamond layer ( 2 ), which has a main cutting element ( 3 ) having a radius R in the layer plane and an opposing, at least segmental linear contact edge ( 4 ). The minimal radius of curvature K is greater than R/20 in a transition zones (X, X′) of the main cutting element ( 3 ) to the contact edge ( 4 ). The transition areas (X, X′) of lesser curvature are produced in post-processing.

What is claimed is:  
     
         1 . A hard material insert for a tool that is configured in segments and has a planar, polycrystalline diamond layer ( 2 ) having a main cutting element ( 3 ) with at least segmental a radius R and an opposing, at least segmental linear contact edge ( 4 ) in the layer plane, wherein the minimal radius of curvature K is greater than R/20 in a transition zone (X, X′) of the main cutting element ( 3 ) to the contact edge ( 4 ).  
     
     
         2 . The hard material insert of  claim 1 , wherein a width W of the contact edge is a width in the range of R/2 to 2R relative to the radius R of an at least segmental circular PCD layer blank and at least part of the main cutting element ( 3 ).  
     
     
         3 . The hard material insert of  claim 2 , wherein a height H measured perpendicular to the contact edge ( 4 ) is in a range of W/2 to 3W/2 relative to the width W of the contact edge.  
     
     
         4 . The hard material insert of  claim 3 , wherein a scallop ( 7 ) is disposed in the contact edge ( 4 ).  
     
     
         5 . The hard material insert of  claim 4 , wherein the scallop ( 7 ) is situated in a central zone.  
     
     
         6 . A process for manufacturing a hard material insert ( 1 ), wherein, in a first process step, a PCD layer blank ( 6 ) is produced and, in a second process step, at least one segmental hard material insert ( 1 ) is separated mosaic-like from the PCD layer blank ( 6 ), and in a further process step a transition zone (X, X′) having a minimal curvature is produced.