Drilling tool

Abstract

The invention relates to a drilling tool (50), in particular a dowel hole drill, for the machining of workpieces, in particular workpieces made of wood, plastics, composite materials, comprising a drill shaft (56) with a front surface (60), and to a drill head (58) with at least one cutting edge (66), which is firmly connected, such as soldered, to the drill shaft (56). In order to make available a drilling tool of the type mentioned at the start, which has a broad range of application and is simple to produce, it is provided that the drill head (58) is formed from a composite material with exclusively two layers (38), namely a hard metal layer (36) and an ultra-hard layer (38) which is connected to the hard metal layer (36) and preferably formed from polycrystalline diamond or polycrystalline boron nitride, that the ultra-hard layer (38) is connected directly to the front surface (60) of the drill shaft (56) and that the at least one cutting edge (66) is formed by the ultra-hard layer (38), and a drill bit (62) such as a centering tip is formed by the hard metal layer (36).

1 . A drilling tool ( 30 ,  50 ), in particular a dowel hole drill, for the machining of workpieces, in particular workpieces made of wood, plastics, composite materials, comprising a drill shaft ( 34 ,  56 ) with a front surface ( 32 ,  60 ) as well as a drill head ( 40 ,  58 ) with at least one cutting edge ( 42 ,  64 ,  66 ), which is firmly connected, such as soldered, to the drill shaft ( 34 ,  56 ),
 characterized in that   the drill head ( 40 ,  58 ) is formed from a composite material with exclusively two layers ( 36 ,  38 ), namely a hard metal layer ( 36 ) and an ultra-hard layer ( 38 ) connected to the hard metal layer ( 36 ), which is formed from preferably polycrystalline diamond or polycrystalline boron nitride, that the ultra-hard layer ( 38 ) is connected directly to the front surface ( 60 ) of the drill shaft ( 34 ,  56 ), and that the at least one cutting edge ( 42 ,  64 ,  66 ) is formed by the ultra-hard layer ( 38 ), and a drill bit ( 62 ), such as a centering tip, is formed by the hard metal layer ( 36 ).   
     
     
         2 . The drilling tool according to  claim 1 ,
 characterized in that   the ultra-hard layer ( 16 ,  38 ) is soldered, in particular vacuum soldered, to the basic body ( 10 ,  34 ,  56 ).   
     
     
         3 . The drilling tool according to  claim 1 ,
 characterized in that   the cutting edge ( 42 ,  64 ,  66 ) and an adjoining chipping surface ( 44 ,  74 ,  78 ) is produced by ablation in some areas of the hard metal support layer ( 36 ), preferably by a grinding, laser or die sinking process, in a surface of the ultra-hard layer ( 38 ), which adjoins the hard metal support layer ( 36 ), or that the sections of the cutting edge ( 42 ,  64 ,  66 ) of the drill bit or cutting bit with adjoining chipping surface ( 44 ,  76 ,  78 ) are formed in the hard metal support layer ( 36 ) and the ultra-hard layer ( 38 ), wherein the sections of the cutting edge ( 42 ) of the drill bit or cutting bit preferably transition continuously into one another.   
     
     
         4 . The drilling tool according to  claim 1 ,
 characterized in that   the active portion ( 46 ) of the cutting element ( 35 ) is produced preferably by a grinding, laser or die sinking process from the hard metal support layer ( 14 ,  36 ).   
     
     
         5 . The drilling tool according to  claim 1 ,
 characterized in that   the drilling tool ( 30 ,  50 ) is designed as a spiral drill, a dowel hole drill, a sickle drill or a step drill, wherein the cutting element ( 40 ) or the drill head ( 58 ) is connected, such as soldered, in the form of a cylindrical body with its ultra-hard layer ( 38 ) on the front surface ( 32 ) of a cylindrical steel, ceramic or hard metal shaft as basic body ( 34 ), and wherein the active portion ( 46 ) forms the drill bit of the drill.   
     
     
         6 . The drilling tool according to  claim 1 ,
 characterized in that   a thickness ratio D HB /D SB  exists between a thickness of the hard metal layer and a thickness D SB  of the ultra-hard layer in the range of 0.2≤D HB /D UB ≤5.0, preferably 0.3≤D HB /D UB ≤2.0.