| Twist drill and method for producing a twist drill which method includes forming a flute of a twist drill -> Monitor Keywords |
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  Twist drill and method for producing a twist drill which method includes forming a flute of a twist drillUSPTO Application #: 20070081870Title: Twist drill and method for producing a twist drill which method includes forming a flute of a twist drill Abstract: There is now provided a twist drill and a method for producing a twist drill which method includes forming a flute of a twist drill. The drill has drill material and a tip portion with a cutting lip. The drill has a land structure and a flute to remove chip residue. The land structure has a flute wall and a cutting edge structure that is disposed longitudinally along the flute wall. The cutting edge structure has a first portion at the drill tip portion and a second portion disposed away from the drill tip portion. The flute wall extends further into the land structure at the second portion of the cutting edge structure than at the tip portion to provide a greater amount of drill material at the tip portion than at the second portion of the cutting edge structure. The flute wall extends further into the land structure at the second portion of the cutting edge structure than at the tip portion to provide a greater flute volume per length at the second portion of the cutting edge structure than at the drill tip portion. The method provides for forming a drill with a grinding tool to form different angular transitions of the cutting edge structure. (end of abstract)
Agent: Kennametal Inc. - Latrobe, PA, US Inventors: Dieter MUHLFRIEDEL, Bernhard BORSCHERT, Jurgen SCHWAGERL USPTO Applicaton #: 20070081870 - Class: 408230000 (USPTO) Related Patent Categories: Cutting By Use Of Rotating Axially Moving Tool, Tool Or Tool With Support, Having Peripherally Spaced Cutting Edges, With Axially Extending Relief Channel, Spiral Channel The Patent Description & Claims data below is from USPTO Patent Application 20070081870. Brief Patent Description - Full Patent Description - Patent Application Claims
CONTINUING APPLICATION DATA [0001] This application is a Continuation-in-Part application of International Application No. PCT/EP01/05751, filed on May 19, 2001, and claiming priority from German Patent Application No. DE 100 27 544.3, filed on Jun. 2, 2000. International Application No. PCT/EP01/05751 was pending as of the filing date of this application. The United States was an elected state in International Application No. PCT/EP01/05751. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] This invention relates to a twist drill and method for producing a twist drill which method includes forming a flute of a twist drill. [0004] 2. Background Information [0005] On a conventional bit for a twist drill, the generally two main cutting edges are curved via the chisel edge so that they run into one another in the shape of an "S". Adjacent to each of the main cutting edges is a main clearance face which transitions into a flute which is realized so that it runs in a spiral shape in the longitudinal direction of the drill. The secondary cutting edge is formed on one of the peripheral sides of the respective flute and transitions into the main cutting edge, forming a face edge. The secondary cutting edge is therefore the cutting edge that extends in a spiral shape in the longitudinal direction of the drill along the respective flute. The term "bit" is used here to designate a longitudinal area of the drill which begins at the end-cutting edge (main cutting edge and chisel edge) and has a length which equals approximately twice the diameter of the drill. [0006] The secondary cutting angle, as defined above, indicates appropriately the geometric orientation of a wedge that forms the secondary cutting edge with reference to the radial direction, i.e. the direction perpendicular to the longitudinal axis of the drill. The term "positive secondary cutting angle", i.e. a cutting angle of more than 0.degree., is therefore used when the wedge forms an acute angle. On conventional bits with the curved realization of the main cutting edges and the chisel edge, there is a positive secondary cutting angle. This secondary cutting angle extends with a constant value over the entire cutting length of the drill. [0007] The positive secondary cutting angle has the advantage that the contact area between the chips removed from the workpiece during the drilling process and the wall of the boring in the workpiece is minimized. The chips are therefore discharged very rapidly. In the vicinity of the main cutting edges, however, the positive secondary cutting angle has the disadvantage that the cutting wedge is comparatively weak in the vicinity of the face edge on account of its acute-angle geometry. However, precisely in the vicinity of the face edge is where very high forces occur during drilling. The load is further increased by the fact that during drilling, the face edge digs into the material, so to speak. Thus at this point in particular there is a danger that the drill will break off. A further disadvantage is that the chip thrown off is curved, which requires an additional exertion of force and thus additional cutting efficiency. [0008] To avoid these problems of the positive secondary cutting angle in the vicinity of the major cutting edges, one possibility is to provide a secondary cutting angle with a value of 0.degree.. In this case, therefore, the main cutting edges run in a straight line toward the chisel edges. Consequently the cutting wedge is relatively massive in the vicinity of the cutting face and is therefore stable. The risk of an overload in this area is therefore kept low. A secondary cutting angle of 0.degree., however, has the significant disadvantage that the chip will not be removed from the boring wall quickly enough over the cutting length of the drill. Under some conditions, this leads to an undesirable surface roughness of the boring wall. For the realization of a secondary cutting angle of 0.degree., an expensive shaped grinding wheel with a complex geometry is required during the grinding of the drill. On the other hand, with a positive secondary cutting angle, a standard grinding wheel with a simple geometry can be used, which is relatively advantageous. OBJECT OF THE INVENTION [0009] The object of the invention is to reduce the above mentioned disadvantages. SUMMARY OF THE INVENTION [0010] The invention teaches in one embodiment that this object can be accomplished by a twist drill configured to drill a hole in a metal object, said twist drill comprising: a cylindrical drill body; said drill body having a central longitudinal axis of rotation about which said drill is configured to rotate during use; a shank portion; said shank portion being configured to be retained by an arrangement to rotate said drill to cut a hole in a metal object; a cutter portion; said cutter portion comprising a first portion being disposed immediately adjacent said shank portion and also comprising a second portion opposite said first portion of said cutter portion; a tip portion configured to drill a hole in a metal object to be drilled; said tip portion comprising: a base portion and a top portion; said base portion being disposed immediately adjacent said second portion of said cutter portion; an at least partially conical surface; a first chip face and a second chip face, each forming a portion of said at least partially conical surface of said tip portion; a second chip face forming a portion of said at least partially conical surface of said tip portion; a chisel edge arrangement configured to initiate cutting of an object to be drilled; [0011] said chisel edge arrangement being disposed between said first chip face and said second chip face; said chisel edge arrangement comprising: a first chisel edge portion and a second chisel edge portion; each of said chisel edge portions being disposed to extend away from each other from said central longitudinal axis; and said first chisel edge portion and said second chisel edge portion being symmetric with respect to one another about said central longitudinal axis; said tip portion also comprising: a first, primary, cutting lip, configured to drill a hole in a metal object, being disposed between said first chisel edge portion and said base portion of said tip portion; a second, primary, cutting lip, configured to drill a hole in a metal object, being disposed between said second chisel edge portion and said base portion of said tip portion; said first cutting lip and said second cutting lip being substantially symmetric with respect to one another about said central longitudinal axis; said cutter portion comprising: a first and a second helical land structure, each being configured and disposed to provide a first helical flute surface and a second helical flute surface, both flute surfaces being configured to remove chip residue produced by said drill upon drilling; said first helical land structure and said second helical land structure each comprising: a first, leading, flute wall configured and disposed to make cutting contact with a metal object to be drilled by said drill; a second, trailing, flute wall; the leading flute wall being configured to lead the trailing flute wall in the direction of rotation upon drilling of a metal object; and an at least partially cylindrical land surface that is disposed further away from said longitudinal axis of rotation than a substantial portion of its corresponding flute surface; the leading flute wall of said first helical land structure being joined to the trailing flute wall of said second helical land structure to configure said first helical flute surface; the leading flute wall of said second helical land structure being joined to the trailing flute wall of said first helical land structure to configure said second helical flute surface; each leading flute wall of said first helical land structure and said second helical land structure comprising corresponding first and second longitudinal cutting edge structures, each longitudinal cutting edge structure being disposed at least along a substantial portion of its corresponding leading flute wall of its corresponding helical land structure; each longitudinal cutting edge structure having a first portion disposed at or adjacent said base portion of said tip portion and also having a second portion disposed away from said tip portion of said drill; each leading flute wall of said first and second helical land structures having a first portion being disposed at or adjacent its corresponding longitudinal cutting edge structure, each said first portion of each leading flute wall being disposed at or adjacent said tip portion; and [0012] each at least partially cylindrical land surface having a first portion being disposed at or adjacent its corresponding longitudinal cutting edge structure, each said first portion of each land surface being disposed at or adjacent said tip portion; each said first portion of each leading flute wall and each adjacent corresponding first portion of each corresponding at least partially cylindrical land surface being disposed at a first angle with respect to one another; each leading flute wall of said first and second helical land structure having a second portion being disposed at or adjacent its corresponding longitudinal cutting edge structure, each said second portion of each leading flute wall being disposed at or adjacent its corresponding second portion of said longitudinal cutting edge structure; each at least partially cylindrical land surface having a second portion being disposed at or adjacent its corresponding longitudinal cutting edge structure, said second portion of said land surface being disposed at or adjacent its corresponding second portion of said longitudinal cutting edge structure; each said second portion of each leading flute wall and each adjacent corresponding second portion of each corresponding at least partially cylindrical land surface being disposed at a second angle with respect to one another; and said first angle being greater than said second angle; each leading flute wall being configured to extend further into its corresponding helical land structure at its corresponding second portion of its corresponding cutting edge structure than at said tip portion of said drill to provide a greater amount of drill material at said tip portion at or adjacent its corresponding cutting lip of said drill to minimize stress at said tip portion at or adjacent its corresponding cutting lip and to provide a greater flute volume of its corresponding helical flute per length along said longitudinal axis of rotation at its corresponding second portion that is disposed away from said tip portion than the flute volume of its corresponding helical flute per length along said longitudinal axis of rotation at said tip portion to maximize removal of chip residue in its corresponding flute upon drilling. [0013] The invention also teaches in one embodiment that this object can be accomplished by a drill configured to drill a hole in an object, said drill comprising: a longitudinal axis of rotation about which said drill is configured to rotate during use; a first portion configured to be retained by an arrangement to rotate said drill to cut a hole in an object; a second portion; and a tip portion configured to drill a hole in an object to be drilled; said second portion being disposed between said first portion and said tip portion; said tip portion comprising: at least one cutting lip configured to drill a hole in an object; said second portion comprising at least one land structure; each said at least one land structure comprising: a first, leading, edge configured and disposed to make cutting contact with an object to be drilled by said drill upon drilling; a second, trailing, edge; said first, leading, edge being configured to lead said second, trailing edge in the direction of rotation upon drilling of an object; a first, leading, wall configured to form a first side of said at least one land structure; said leading wall being disposed from said leading cutting edge towards said longitudinal axis of rotation; a second, trailing, wall configured to form a second side of said at least one land structure; [0014] said trailing wall being disposed from said trailing edge towards said longitudinal axis of rotation; said leading wall and said trailing wall being configured to form a flute surface being disposed towards said longitudinal axis of rotation to remove chip residue produced during drilling; a land surface disposed between said leading cutting edge and said trailing edge of said at least one land structure; said land surface being disposed further away from said longitudinal axis of rotation than a substantial portion of said flute surface; said leading cutting edge of said at least one land structure comprising a cutting edge structure disposed longitudinally along a portion of said at least one land structure; said longitudinal cutting edge structure having a first portion disposed at said tip portion of said drill; said longitudinal cutting edge structure also having a second portion disposed away from said tip portion of said drill towards said first portion of said drill; a first portion of said leading wall of said at least one land structure being disposed at or adjacent said cutting edge structure, said first portion of said leading wall being disposed at or adjacent said tip portion; and a first portion of said land surface being disposed at or adjacent said cutting edge structure, said first portion of said land surface being disposed at or adjacent said tip portion; [0015] said first portion of said leading wall and said first portion of said land surface being disposed at a first angle with respect to one another; a second portion of said leading wall of said at least one land structure being disposed at or adjacent said cutting edge structure, said second portion of said leading wall being disposed at or adjacent said second portion of said cutting edge structure; a second portion of said land surface being disposed at or adjacent said cutting edge structure, said second portion of said land surface being disposed at or adjacent said second portion of said cutting edge structure; said second portion of said leading wall and said second portion of said land surface being disposed at a second angle with respect to one another; and said first angle being greater than said second angle. [0016] The invention further teaches in one embodiment that the object can be accomplished by a method of manufacture of a drill configured to drill a hole in an object, said drill comprising: a drill material; a longitudinal axis of rotation about which said drill is configured to rotate during use; a tip portion comprising at least one cutting lip; and at least one land structure configured to form at least one flute to remove chip residue produced upon drilling; each said at least one land structure comprising at least one flute wall and a cutting edge structure; said cutting edge structure being disposed longitudinally along at least a portion of said at least one flute wall of said at least one land structure; said cutting edge structure comprising a first portion at or adjacent said tip portion and a second portion disposed away from said tip portion; and at least one of (a.) and (b.), wherein (a.) and (b.) are: (a.) said drill material comprising the same drill material from said tip portion to said second portion of said cutting edge structure disposed away from said tip portion; and [0017] said at least one flute wall being configured to extend further into at least one adjacent land structure at said second portion of said cutting edge structure than into at least one land structure at or adjacent said tip portion of said drill to provide a greater amount of said drill material at said tip portion; and (b.) said at least one flute wall being configured to extend further into at least one adjacent land structure at said second portion of said cutting edge structure than into at least one land structure at or adjacent said tip portion of said drill to provide a greater flute volume of said at least one flute per length along said longitudinal axis at said second portion of said cutting edge structure that is disposed away from said tip portion than the flute volume of said at least one flute per length along said longitudinal axis at said tip portion; said method comprising: forming said drill to make at least one of (c.) and (d.), wherein (c.) is: (c.) extending said at least one flute wall further into said at least one adjacent land structure at said second portion of said cutting edge structure than into said at least one land structure at or adjacent said tip portion of said drill to provide a greater amount of said drill material at said tip portion than at said second portion of said cutting edge structure; wherein said drill material comprises the same drill material from said tip portion to said second portion of said cutting edge structure disposed away from said tip portion; and wherein (d.) is: (d.) extending said at least one flute wall further into said at least one adjacent land structure at said second portion of said cutting edge structure than into said at least one land structure at or adjacent said tip portion of said drill to provide a greater flute volume of said at least one flute per length along said longitudinal axis at said second portion of said cutting edge structure that is disposed away from said tip portion than the flute volume of said at least one flute per length along said longitudinal axis at said tip portion. [0018] The invention also teaches that this object can be accomplished by a drill configured to drill a hole in an object, said drill comprising: a drill material; a longitudinal axis of rotation about which said drill is configured to rotate during use; a tip portion comprising at least one cutting lip; and at least one land structure configured to form at least one flute to remove chip residue produced upon drilling; each said at least one land structure comprising at least one flute wall and a cutting edge structure; said cutting edge structure being disposed longitudinally along at least a portion of said at least one flute wall of said at least one land structure; said cutting edge structure comprising a first portion at or adjacent said tip portion and a second portion disposed away from said tip portion; and at least one of (a.) and (b.), wherein (a.) and (b.) are: (a.) said drill material comprising the same drill material from said tip portion to said second portion of said cutting edge structure disposed away from said tip portion; and [0019] said at least one flute wall being configured to extend further into at least one adjacent land structure at said second portion of said cutting edge structure than into at least one land structure at or adjacent said tip portion of said drill to provide a greater amount of said drill material at said tip portion than at said second portion of said cutting edge structure; and (b.) said at least one flute wall being configured to extend further into at least one adjacent land structure at said second portion of said cutting edge structure than into at least one land structure at or adjacent said tip portion of said drill to provide a greater flute volume of said at least one flute per length along said longitudinal axis at said second portion of said cutting edge structure that is disposed away from said tip portion than the flute volume of said at least one flute per length along said longitudinal axis at said tip portion. [0020] The invention teaches in one embodiment a bit for a twist drill that has a plurality of main cutting edges that are connected with one another by a chisel edge, adjacent to which main cutting edges in the longitudinal direction of the drill are secondary cutting edges that run along flutes, whereby different secondary cutting angles are defined in the longitudinal direction of the drill. Continue reading... Full patent description for Twist drill and method for producing a twist drill which method includes forming a flute of a twist drill Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Twist drill and method for producing a twist drill which method includes forming a flute of a twist drill patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. 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