Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23C—MILLING
  • B23C5/00—Milling-cutters
  • B23C5/02—Milling-cutters characterised by the shape of the cutter
  • B23C5/10—Shank-type cutters, i.e. with an integral shaft
  • B23C5/1081—Shank-type cutters, i.e. with an integral shaft with permanently fixed cutting inserts 
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23C—MILLING
  • B23C5/00—Milling-cutters
  • B23C5/02—Milling-cutters characterised by the shape of the cutter
  • B23C5/10—Shank-type cutters, i.e. with an integral shaft
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23C—MILLING
  • B23C5/00—Milling-cutters
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
  • B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
  • B23P15/28—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass cutting tools
  • B23P15/34—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass cutting tools milling cutters
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23C—MILLING
  • B23C2226/00—Materials of tools or workpieces not comprising a metal
  • B23C2226/12—Boron nitride
  • B23C2226/125—Boron nitride cubic [CBN]
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23C—MILLING
  • B23C2226/00—Materials of tools or workpieces not comprising a metal
  • B23C2226/31—Diamond
  • B23C2226/315—Diamond polycrystalline [PCD]
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23C—MILLING
  • B23C2240/00—Details of connections of tools or workpieces
  • B23C2240/08—Brazed connections

Definitions

• This invention relates to an endmill with cBN (cubic boron nitride) or PCD (polycrystalline diamond) in the cutting edges and a method of making the same.
• the purpose of the method is to decrease the cost compared to existing methods.
• An endmill is used for machining of grooves, pockets and slots and consists of a cylindrical holder with cutting means at the end. It can be made of high speed steel, or solid cemented carbide, but it can also consist of a steel holder with cemented carbide inserts as cutting means .
• metal cutting inserts having cutting edges formed of a superhard material, such as PCD are usually used for the machining of non-ferrous alloys such as brass, magnesium and aluminium, and the like, whereas inserts with cutting edges formed of a superhard abrasive, such as cBN are usually used for the machining of cast iron and hardened steel and the like.
• PCD or cBN endmills there are several types of PCD or cBN endmills on the market today. Essentially there are two different methods to manufacture them. One method includes sintering cBN or diamond powder under elevated pressure and temperature into a solid cylindrical body which is then brazed onto a shank and finished into an endmill . The other method includes bonding a layer of cBN or diamond under elevated pressure and temperature to a substrate, usually a cemented carbide disc, from which smaller pieces, "chips", are cut out. These chips are then brazed onto a cemented carbide rod and ground to the finished shape. Tools produced that way are normally quite expensive due to the many steps the product must undergo before it is finished.
• the object of the present invention is therefore to provide a method, where an endmill with several cutting edges can be achieved but at a substantially lower cost.
• Fig 1 shows the principle of the method where 1 is the element that will form the cutting part,
• FIG. 5 is a top view of the element 1 after shaping to expose the cutting edges.
• the starting point is a cemented carbide disc preferably with a binder phase content of >10 wt-% provided with superhard bodies according to the teachings of US 5,676,496.
• the cemented carbide disc is made from a cemented carbide rod with a circular, square, triangular or other suitable cross section preferably with a center hole.
• This rod one or more grooves are ground throughout its whole length and parallel to its axis.
• the groove can be straight but it can also be helical.
• the number of grooves and their location depend on the type of disc that is to be produced.
• the shape of the grooves can be made in different ways. It is important, however, that they have a rounded or plane shape. Their size shall be such that the cutting work essentially is performed by the superhard material . After HP/HT sintering the rod is cut into discs of desired thickness .
• cemented carbide discs at least one groove is ground and filled with a powder mixture containing cBN and/or diamond after which the discs are treated at a temperature and pressure where cBN and/or diamond is stable. During this treatment the discs are separated from each other in such a way that they do not sinter together.
• the shank 2 is preferably made in cemented carbide preferably with a binder phase content of >10 wt-%. The diameter of the shank is somewhat smaller than the diameter of the disc with superhard materials . The other end of the shank is provided with clamping means .
• the PCD/cBN disc is then brazed together with the shank .
• the end of the shank where the PCD/cBN disc is brazed is ground down to form a tenon, 4.
• the shape of the tenon is generally cylindrical but it may alternatively be tapered, square, triangular, elliptical or other non-round shape.
• the diameter (or equivalent) of the tenon is about 15 - 40 % of the diameter of the shank and is designed to fit within the center hole of the disc 1 although the tenon does not have to extend through the entire length of that center hole.
• the PCD/cBN disc is then brazed together with the shank using the tenon as guide and braze joint, 3. It is according to the invention essential that brazing is made only at the tenon. This will minimise the risk of braze joint failure.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Earth Drilling (AREA)
• Drilling Tools (AREA)
• Cutting Tools, Boring Holders, And Turrets (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20407402

Family Applications (1)

Country Status (8)

Cited By (3)

Families Citing this family (6)

Citations (2)

• 1997
  • 1997-06-13 SE SE9702297A patent/SE512752C2/sv not_active IP Right Cessation
• 1998
  • 1998-06-10 EP EP98929975A patent/EP0988125A1/en not_active Withdrawn
  • 1998-06-10 WO PCT/SE1998/001113 patent/WO1998056528A1/en not_active Application Discontinuation
  • 1998-06-10 CA CA002290023A patent/CA2290023A1/en not_active Abandoned
  • 1998-06-10 JP JP50229099A patent/JP2002504027A/ja active Pending
  • 1998-06-10 KR KR19997011706A patent/KR20010013691A/ko not_active Application Discontinuation
  • 1998-06-10 CN CN98806156A patent/CN1260742A/zh active Pending
  • 1998-06-12 ZA ZA985147A patent/ZA985147B/xx unknown

Patent Citations (2)

Also Published As

Similar Documents

Legal Events