METHOD AND TOOL FOR CREATING A THROUGH-THREAD

Abstract

In a method for creating a through-thread, thread creation means is moved in a screw-in movement in an axial forward direction (VR) through a workpiece from a first workpiece side to a second workpiece side opposite the first workpiece side such that the end face projects out of the workpiece, wherein the thread creation means is moved through the workpiece, in particular along a first line which is a helical line, wherein then, to create at least one countersink, the thread creation means is moved in a countersinking movement, in particular along a second line that differs from the first line, and wherein, for subsequent withdrawal, the thread creation means is moved back through the workpiece in a screw-out movement in the axial backward direction (RR), in particular at least substantially along the first line.

Claims

1-28. (canceled)

29. A method for creating a through-thread, in particular a through-threaded hole, with a predefined thread pitch and with a predefined thread profile with at least one countersink in a workpiece by means of a tool, wherein: a) the tool can be rotated about a tool axis (A) extending through the tool and moved axially in relation to the tool axis, in particular by means of a turning device, b) the tool has, sequentially in the direction of the end face thereof, b1) a shank region, in particular for coupling to the turning device, b2) at least one neck region, in particular with one or two flute and/or helical flute regions, for transporting away chips, b3) a thread creation region with a thread creation means for creating the through-thread, and b4) an end region having the end face, c) to create the through-thread, the thread creation means is moved in a screw-in movement in an axial forward direction (VR) through the workpiece from a first workpiece side to a second workpiece side opposite the first workpiece side such that the end face projects out of the workpiece, wherein the thread creation means is moved through the workpiece, in particular along a first line, which is a helical line, d) then, to create at least one countersink, the thread creation means is moved in a countersinking movement, in particular along a second line that differs from the first line, and e) for subsequent withdrawal, the thread creation means is moved back through the workpiece in a screw-out movement in an axial backward direction (RR), in particular at least substantially along the first line.

30. The method as claimed in claim 29, wherein: a) to create the through-thread, the thread creation means is moved in the screw-in movement in the axial forward direction (VR) through the workpiece from a first position (P11, P21, P31) on a first workpiece side to a second position (P12, P22, P32) on a second workpiece side opposite the first workpiece side such that the end face projects out of the workpiece at the second position (P12, P22, P32), and the thread creation means is moved through the workpiece along a first line which is a helical line, b) then, to create at least one countersink in the countersinking movement, the thread profile is moved in a rotary movement from the second position (P12, P22, P32) along a second line that differs from the first line to a third position (P13, P23, P33) or back to the second position (P12, P22, P32), and c) for subsequent withdrawal, the thread creation means is moved back in the screw-out movement from the second position (P12, P22, P32), or from the third position (P13, P23, P33), through the workpiece along the first line to the first position (P11, P21, P31) in an axial backward direction (RR).

31. The method as claimed in in claim 29, wherein the screw-in movement comprises a rotary movement of the tool with a predefined direction of rotation about the tool axis (A) and an axial feed movement (V), which is synchronized with the rotary movement according to the thread pitch, in the axial forward direction (VR) axially with respect to the tool axis (A) such that an axial feed of the tool by the predefined thread pitch corresponds to a full revolution of the tool about the tool axis (A) and/or such that the thread creation means is moved through the workpiece on a first line in order to create the through-thread, wherein the first line is a helical line.

32. The method as claimed in in claim 29, wherein: the second line comprises a second helical line in the axial forward direction (VR) and/or the backward direction (RR) such that less than an axial feed of the tool by the predefined thread pitch corresponds to a full revolution of the tool about the tool axis (A), or the second line comprises a circular movement with an at least substantially constant axial feed.

33. The method as claimed in in claim 29, wherein: the thread creation region comprises the thread creation means, which is arranged in particular at and/or near the end face, wherein the thread creation means comprises a thread groove, in particular exactly one thread groove, and/or wherein the thread creation means is interrupted by at least one flute, and/or the thread creation means has at least one thread tooth, which is designed and arranged to match the predefined thread pitch, and has an effective profile which corresponds to the thread profile of the through-thread, wherein in particular the at least one thread tooth cuts the thread into the workpiece.

34. The method as claimed in in claim 29, wherein: the at least one thread tooth is moved through the workpiece on the helical line during the screw-in movement, and/or the countersinking movement comprises or is reverse countersinking.

35. The method as claimed in in claim 29, wherein: the at least one neck region has a first neck region and a second neck region, in particular, the first neck region has a first neck diameter and the second neck region has a second neck diameter, wherein the first neck diameter is preferably greater than the second neck diameter, and/or a first conical region is arranged between the neck region and the thread creation region, and a second conical region is arranged, in particular, between the first neck region and the second neck region, wherein, in particular, the first conical region widens the neck diameter of the tool in the direction of the end face and the second conical region tapers the neck diameter of the tool in the direction of the end face.

36. The method as claimed in in claim 29, wherein the end region comprises a drilling region for drilling a through-hole, wherein, in particular, the drilling region comprises at least two end and/or main cutting edges, wherein a guide region is preferably formed on the outer sides thereof, the guide region is, in particular, of cylindrical design, the two end and/or main cutting edges each preferably interrupt the guide region, and/or the second neck region has, in particular, a smaller diameter than the guide region of the drilling region.

37. The method as claimed in in claim 29, wherein the through-hole, the through-thread and the at least one countersink can be or are created in one operation by means of the same tool, in particular by means of a feed movement in the forward direction (VR) on the helical line, a countersinking process directly following this and a backward movement, directly following this, in the backward direction (RR) on the helical line.

38. The method as claimed in in claim 29, wherein from the at least one neck region as far as the end face, exactly two, exactly three, at least two or at least three tap bodies extend parallel to the tool axis (A) or spirally with a twist angle (B) about the tool axis (A), and are separated from one another by flutes.

39. The method as claimed in in claim 29, wherein the flutes extend from the end and/or main cutting edges through the thread creation region and the at least one flute or neck region, thus enabling chips to be transported away rearward from the end and/or main cutting edges.

40. The method as claimed in claim 29, wherein: a first countersinking means comprises the first conical region and/or the thread creation region, wherein, in particular, the first conical region merges directly into the thread creation region, and/or the countersinking means is formed exclusively by the thread creation region, and/or a first countersinking means is formed by the first conical region on the tool and/or wherein a second countersinking means is formed by the second conical region on the tool.

41. The method as claimed in claim 29, wherein the distance between the first and second countersinking means corresponds substantially to the thickness of the workpiece.

42. The method as claimed in claim 29, wherein, during the creation of the through-thread, a through-hole is simultaneously produced by means of the tool during the screw-in movement, or wherein the through-thread is created in a through-hole.

43. The method as claimed in claim 29, wherein: the countersinking movement is a circular movement by means of which a countersink is produced on the first and/or on the second workpiece side by means of a first countersinking means and/or a countersink is produced on the first workpiece side by means of a second countersinking means, and in particular, the tool axis (A) of the tool is deflected by a predefined radius (r) from the thread center axis (M) during the circular movement, and the tool is moved on a circular path with the predefined radius (r) about the thread center axis, wherein the tool is additionally rotated about its tool axis (A).

44. The method as claimed in claim 29, wherein: during the countersinking movement, a first countersink is made by means of the first countersinking means through the first conical region on the tool; and a second countersink is simultaneously made by means of the second countersinking means through the second conical region on the tool.

45. The method as claimed in claim 29, wherein: the countersink is conical, with a maximum diameter which is greater than the maximum diameter of the thread profile or equal to the maximum diameter of the thread profile, and/or the countersink creates a chamfer, in particular on the first and/or second workpiece side and/or at the start and/or end of the through-thread.

46. The method as claimed in claim 29, wherein: the countersinking movement is a movement along a circular line by means of which a countersink, in particular a cylindrical countersink, is produced on the first workpiece side by means of a/the first countersinking means, and/or the countersinking movement is a non-helical movement by means of which a countersink is produced on the second workpiece side, and/or the feed is at least temporarily reduced during the countersinking movement, in particular in such a way that the feed during one revolution of the tool is less than the predefined thread pitch, and/or the countersinking movement takes place in the forward direction (VR) and/or in the backward direction (RR).

47. The method as claimed in claim 29, wherein: to create the countersink, the end face is moved from the second position (P12, P22, P32) to the third position (P13, P23, P33) in the forward direction, and the second and third positions each lie on the helical line, or to create the countersink, the end face is moved from the second position (P12, P22, P32) to the third position (P13, P23, P33) in the backward direction, and the second and third positions each lie on the helical line, or to create the countersink, the end face is moved in the forward direction from the second position (P12, P22, P32) to the third position (P13, P23, P33) and then in the backward direction again to the second position.

48. The method as claimed in claim 29, wherein: the countersink is cylindrical, with a diameter which is preferably greater than the maximum diameter of the thread profile or equal to the maximum diameter of the thread profile, and/or the countersink is created, in particular, on the first and/or second workpiece side and/or at the start and/or end of the through-thread.

49. The method as claimed in claim 29, wherein: the first position (P11, P21, P31) is arranged at an entry point to the workpiece and/or the second position (P12, P22, P32) is arranged at an exit point from the workpiece, and/or at least one feed (V) and one rotation angle (□) are assigned to each position (P11-P13, P21-P23, P31-P33) of the tool (100), and/or a position (P11-P13, P21-P23, P31-P33) is defined by a rotation angle (□), a linear displacement (V) in the axial direction and, in particular, a radial deflection (r) of the tool of the tool axis (A) from the thread center axis (M).

50. A tool, in particular for carrying out the method as claimed in claim 29, having an end face, comprising, sequentially in the direction of the end face thereof: a shank region, in particular for coupling to the turning device, at least one neck region, in particular with one or two flute and/or helical flute regions, for transporting away chips, a thread creation region with a thread creation means for creating the through-thread, and an end region having the end face.

51. The tool for carrying out the method as claimed in claim 50, wherein the tool comprises a thread-forming tap, a thread-milling cutter or a thread-cutting tap and/or a drill.

52. The tool for carrying out the method as claimed in claim 50, wherein: the thread creation means has a contour of revolution, in particular, the contour of revolution forms a cutting edge contour for the at least one countersink, and/or in particular, the contour of revolution forms an envelope curve and/or envelope contour, wherein the envelope curve and/or envelope contour are/is formed by countersink cutting edges.

53. The tool for carrying out the method as claimed in claim 50, wherein: the end region comprises a drilling region for drilling a through-hole, the drilling region comprises at least two end and/or main cutting edges, in particular on at least two tap bodies, for creating the through-hole, which extend into the thread creation region for creating the through-thread, flutes extend between the end and/or main cutting edges through the thread creation region and into the at least one flute or neck region, and/or the at least two end and/or main cutting edges form the countersink cutting edges and/or the contour of revolution on the outside diameter.

54. The tool for carrying out the method as claimed in in claim 50, wherein: the tool, in particular the thread creation means, is designed in such a way that it has or creates an at least substantially closed envelope curve and/or envelope contour, in particular, the tool is designed in such a way that it has or creates a closed envelope curve and/or envelope contour, and/or in particular, the tool has at least three end and/or main cutting edges, in particular at least four end and/or main cutting edges, preferably at least five end and/or main cutting edges.

55. The tool for carrying out the method as claimed in claim 50, wherein: the at least one countersink has a countersink angle which is greater than 25° and less than 60°, preferably between 30° and 45°, in particular at least substantially 30°, and/or the envelope curve and/or envelope contour are/is formed by at least one first end and/or main cutting edge, in particular a first shank-side thread-cutting tooth, as a first countersink cutting edge and a second end and/or main cutting edge, in particular a second shank-side thread-cutting tooth, as a second countersink cutting edge, which, in particular jointly, form a closed envelope curve and/or envelope contour during rotation, and/or the envelope curve and/or envelope contour are/is at least substantially conical.

56. The tool for carrying out the method as claimed in claim 50, wherein: the first shank-side thread-cutting tooth and the second shank-side thread-cutting tooth are ground down in such a way with respect to the further thread-cutting teeth of the end and/or main cutting edges that (i) the envelope curve and/or envelope contour of the first shank-side thread-cutting tooth forms the innermost ring of the at least one countersink with the countersink angle, and that (ii) the envelope curve and/or the envelope contour of the second shank-side thread-cutting tooth forms the second-innermost ring, surrounding the innermost ring, of the at least one countersink with the countersink angle; and the second-innermost ring directly surrounds the innermost ring of the at least one countersink, in particular on the outside thereof, and thus preferably at least partially forms the conical countersink.

Description

[0141] The invention is explained in greater detail below by means of exemplary embodiments. Reference is also made to the drawings, in which

[0142] FIGS. 1a to 1l show a combined drilling and thread creation tool during the creation of a through-threaded hole according to a first embodiment,

[0143] FIGS. 2a to 2m show a combined drilling and thread creation tool during the creation of a through-threaded hole according to a second embodiment,

[0144] FIGS. 3a to 3l show a combined drilling and thread creation tool during the creation of a through-threaded hole according to a third embodiment,

[0145] FIG. 4 shows in a diagram the graph of the axial penetration depth as a function of the rotation angle for an entire threaded hole creation cycle,

[0146] FIG. 5 shows the end section of the graph illustrated in FIG. 4 in the forward movement as a braking process,

[0147] FIG. 6 shows the end section of the graph illustrated in FIG. 4 in the backward movement as an acceleration process, and

[0148] FIG. 7 to FIG. 10 show contours of revolution which are formed by the end and/or main cutting edges or thread creation means, in each case schematically.

[0149] In FIGS. 1 to 3, mutually corresponding parts and variables are provided with the same reference signs, although not all reference signs are shown in each figure for the sake of clarity.

[0150] Exemplary embodiments of the tool and method according to the invention are explained below with reference to FIG. 1 to FIG. 3.

[0151] Figure sequences 1 to 3 each show a method for creating a through-thread, in particular a through-threaded hole 163, 263, 363 with a predefined thread pitch 172, 272, 372 and with a predefined thread profile 171, 271, 371 with at least one countersink 164, 264, 364; 262 in a workpiece 150, 250, 350 by means of a tool 100, 200, 300.

[0152] The tool 100, 200, 300 can be rotated about a tool axis A extending through the tool and moved axially in relation to the tool axis, in particular by means of a turning device.

[0153] Sequentially in the direction of its end face 120, 220, 320, the tool has a shank region 211, in particular for coupling to the turning device, at least one neck region 112, 212, 312, in particular with one or two flute and/or helical flute regions, for transporting away chips, a thread creation region 116, 216, 316 with a thread creation means for creating the through-thread 163, 263, 363, and an end region 117, 217, 317 having the end face 120, 220, 320.

[0154] To create the through-thread 163, 263, 363, the thread creation means is moved in a screw-in movement in an axial forward direction VR through the workpiece 150, 250, 350 from a first position P11, P21, P31 on a first workpiece side to a second position P12, P22, P32 on a second workpiece side opposite the first workpiece side, such that the end face projects out of the workpiece at the second position P12, P22, P32, and the thread creation means is moved through the workpiece along a first line, which is a helical line.

[0155] Then, to create at least one countersink, the thread profile 171, 271, 371 is moved in a rotary movement from the second position P12, P22, P32 along a second line, which differs from the first line, to a third position P13, P23, P33 or back to the second position P12, P22, P32 in a countersinking movement.

[0156] For subsequent withdrawal, the thread creation means is moved back in an unscrewing movement from the second position P12, P22, P32, or from the third position P13, P23, P33, through the workpiece along the first line to the first position P11, P21, P31 in an axial backward direction RR.

[0157] The screw-in movement comprises a rotary movement of the tool 100, 200, 300 with a predefined direction of rotation about the tool axis A and an axial feed movement V, which is synchronized with the rotary movement according to the thread pitch 172, 272, 372, in the axial forward direction VR, axially with respect to the tool axis A, such that an axial feed of the tool by the predefined thread pitch 172, 272, 372 corresponds to a full revolution of the tool 100, 200, 300 about the tool axis A.

[0158] This takes place in such a way that the thread creation means is moved through the workpiece on a first line to create the through-thread 163, 263, 363 wherein the first line is a helical line.

[0159] In the embodiment according to FIGS. 3a to 3l, the second line comprises a second helical line in the axial forward direction VR and/or the backward direction RR, such that less than an axial feed of the tool by the predefined thread pitch 372 corresponds to a full revolution of the tool 300 about the tool axis A.

[0160] In the embodiments according to FIG. 1a to 1l and 2a to 1m, the second line comprises or is a circular movement with an at least substantially constant axial feed.

[0161] The thread creation region comprises the thread creation means 116, 216, 316, which is arranged in particular at and/or near the end face 120, 220, 320, wherein the thread creation means comprises a thread groove, in particular exactly one thread groove. The thread creation means is interrupted by at least one flute.

[0162] The thread creation means 116, 216, 316 has at least one thread tooth, in particular a plurality of thread teeth, which is/are designed and arranged to match the predefined thread pitch. The thread creation means 116, 216, 316 furthermore has an effective profile which corresponds to the thread profile of the through-thread, wherein, in particular, the at least one thread tooth cuts the thread into the workpiece.

[0163] The at least one thread tooth is moved through the workpiece on the helical line during the screw-in movement.

[0164] The neck region 212, 214 according to FIGS. 2a to 2m has a first neck region 212 and, in the direction of the end region 217, a second neck region 214.

[0165] The first neck region 212 has a first neck diameter and the second neck region 214 has a second neck diameter. In this embodiment, the first neck diameter is larger than the second neck diameter.

[0166] A first conical region 215 is arranged between the neck region 214 and the thread creation region 216. A second conical region 213 is arranged between the first neck region 212 and the second neck region 214.

[0167] The first conical region 215 widens the neck diameter of the tool in the direction of the end face, and the second conical region 213 tapers the neck diameter of the tool 200 in the direction of the end face.

[0168] The end region 117, 217, 317 comprises a drilling region for drilling a through-hole.

[0169] The drilling region comprises at least two end and/or main cutting edges, wherein a guide region 218 is formed on the outer sides thereof according to FIG. 2a. In particular, the guide region 218 can be of cylindrical design. In particular, the two end and/or main cutting edges each interrupt the guide region 218.

[0170] The second neck region 214 has a smaller diameter than the guide region 218 of the drilling region.

[0171] In particular, the second neck region 214 has a smaller diameter than the thread creation region 216.

[0172] The through-hole, the through-thread and the at least one countersink 164, 264, 364 are created in one operation by means of the same tool 100, 200, 300, in particular by means of a feed movement in the forward direction VR on the helical line, a countersink 164, 264, 364 directly following this and a backward movement, directly following this, in the backward direction RR on the helical line.

[0173] From the at least one neck region 112, 212, 312 as far as the end face 120, 220, 320, exactly two, exactly three, at least two or at least three tap bodies 130, 230, 330; 134, 234, 334 extend parallel to the tool axis A or spirally with a twist angle 3 about the tool axis A, and are separated from one another by flutes 132, 232, 332.

[0174] The flutes extend from the end and/or main cutting edges through the thread creation region 116, 216, 316 and the at least one flute or neck region 112, 212, 312, thus enabling chips to be transported away rearward from the end and/or main cutting edges.

[0175] A first countersinking means comprises the first conical region 215 and/or the thread creation region 116, 216, 316. In the embodiment according to FIGS. 2a to 2m, the first conical region 215 merges directly into the thread creation region 216.

[0176] In the embodiment according to FIGS. 1a to 1l, the countersinking means is formed exclusively by the thread creation region 116.

[0177] In the embodiment according to FIGS. 2a to 2m, a first countersinking means is formed by the first conical region 215 on the tool 200. A second countersinking means is formed by the second conical region 213 on the tool 200.

[0178] In the embodiment according to FIGS. 2a to 2m, the distance between the first and second countersinking means corresponds substantially to the thickness of the workpiece 250.

[0179] During the creation of the through-thread 163, 263, 363, a through-hole is simultaneously produced by means of the tool 100, 200, 300 during the screw-in movement. In an alternative embodiment (not illustrated), a through-thread is created in an already existing through-hole.

[0180] The first position P11, P21, P31 is arranged at an entry point to the workpiece and the second position P12, P22, P32 is arranged at an exit point from the workpiece.

[0181] In the embodiment according to FIGS. 1a to 1l, the countersinking movement is a circular movement by means of which a countersink is produced on the second workpiece side by means of a first countersinking means.

[0182] In the embodiment according to FIGS. 2a to 2m, the countersinking movement is a circular movement by means of which a first countersink is produced on the second workpiece side by means of a first countersinking means 216 and a second countersink is produced on the first workpiece side by means of a second countersinking means 213.

[0183] The tool axis A of the tool 100, 200 is deflected by a predefined radius r from the thread center axis M during the circular movement, and the tool is moved on a circular path with the predefined radius r about the thread center axis M, wherein the tool is additionally rotated about its tool axis A.

[0184] In the embodiment according to FIGS. 2a to 2m, the countersink is conical, with a maximum diameter which is greater than the maximum diameter of the thread profile.

[0185] In the embodiment according to FIGS. 1a to 1l, the countersink creates a chamfer on the second workpiece side 152 at the end of the through-thread.

[0186] In the embodiment according to FIGS. 2a to 2m, the countersink creates a chamfer, in particular on the first workpiece side 251 and on the second workpiece side 252 and thus at the start and end of the through-thread.

[0187] In the embodiment according to FIGS. 3a to 3l, the countersinking movement is a circular movement along a circular line by means of which a cylindrical countersink is produced on the second workpiece side 351 by means of the first countersinking means 316.

[0188] In the embodiment according to FIGS. 3a to 3l, the countersinking movement is a non-helical movement by means of which a countersink is produced on the second workpiece side.

[0189] The feed is at least temporarily reduced during the countersinking movement in the embodiments according to FIGS. 1a to 1l and 2a to 2m, in particular in such a way that the feed during one revolution of the tool is less than the predefined thread pitch.

[0190] In the embodiment according to FIGS. 3a to 3l, the feed is at least temporarily reduced during the countersinking movement, in particular in such a way that the feed during one revolution of the tool is zero.

[0191] The countersinking movement takes place in the forward direction VR and/or in the backward direction RR.

[0192] To create the countersink, the end face can be moved from the second position P12, P22, P32 to the third position P13, P23, P33 in the forward direction, and the second and third positions each lie on the helical line.

[0193] To create the countersink, the end face can be moved from the second position P12, P22, P32 to the third position P13, P23, P33, also or partially in the backward direction, and the second and third positions each lie on the helical line.

[0194] To create the countersink, the end face can furthermore be moved in the forward direction from the second position P12, P22, P32 to the third position P13, P23, P33 and then in the backward direction again to the second position.

[0195] In the embodiment according to FIGS. 1a to 1l, the countersink is cylindrical, with a diameter which is greater than the maximum diameter of the thread profile.

[0196] In the embodiment according to FIGS. 3a to 3l, the countersink is cylindrical, with a diameter which is equal to the maximum diameter of the thread profile.

[0197] In the embodiments according to FIGS. 1a to 1l and FIGS. 3a to 3l, the countersink is created on the second workpiece side 152, 352 and thus at the end of the through-thread.

[0198] In the embodiment according to FIGS. 2a to 2m, a first countersink is created on the first workpiece side 251 and thus at the start of the through-thread and a second countersink is created on the second workpiece side 252 and thus at the end of the through-thread.

[0199] At least one feed V and one rotation angle α are assigned to each position P11-P13, P21-P23, P31-P33 of the tool 100.

[0200] A position P11-P13, P21-P23, P31-P33 is defined by a rotation angle α, a linear displacement V in the axial direction and, in particular, a radial deflection r of the tool 100, 200, 300 with the tool axis A from the thread center axis M.

[0201] Figure sequences 1 to 3 each show a tool, in particular for carrying out the method according to the invention, having an end face, comprising sequentially in the direction of the end face 120, 220, 320 thereof [0202] a shank region 211 (shown only in figure sequence 2), in particular for coupling to the turning device, [0203] at least one neck region 112, 212, 312, in particular with one or two flute and/or helical flute regions, for transporting away chips, [0204] a thread creation region 116, 216, 316 with a thread creation means for creating the through-thread 163, 263, 363, and [0205] an end region 117, 217, 317 having the end face 120, 220, 320.

[0206] The tool for carrying out the method can comprise a thread-forming tap or a thread-cutting tap and/or a drill.

[0207] The turning device is or preferably comprises a CNC machine and/or a machine tool, in particular with CNC control.

[0208] In respect of the embodiment according to FIG. 3, further details for a possible variant of a method according to the invention for creating a through-thread are described below by way of example.

[0209] During the screw-in movement as the first working phase or thread creation phase, the through-hole is created using the tool 300 by means of the end region, and the thread groove in the hole wall is produced immediately axially behind it and at least in part simultaneously by means of the thread creation means. In this first working phase, the axial feed rate along the tool axis A is matched to the speed of rotation for the rotary movement about the tool axis A and synchronized in such a way that, during a full revolution, the axial feed corresponds to the thread pitch P or 372. The axial thread depth in the direction of the tool axis A, measured from the workpiece surface, in this first working phase is designated by T.sub.G.

[0210] In a braking movement as the second working phase immediately following the first working phase, the tool 300 is then braked in a braking process (or: in a braking movement) in a rotation angle interval in such a way that the axial feed V at a rotation angle of 360°, i.e. at a full revolution, of the tool is less than the thread pitch P or 372 and decreases to zero. As a rule, the braking process or the second working phase begins with an axial feed, based on a rotation angle of 360°, which corresponds to the thread pitch P of the first working phase, that is to say V=P, and then reduces the axial feed per 360° rotation angle to values below the thread pitch P, that is to say V<P. The braking process is to be understood as braking from the initial thread pitch V=P to zero at the end or at a reversal point, that is to say V=0, and does not have to include a reduction in the axial feed V as a function of the rotation angle (braking acceleration) over the entire rotation angle interval. On the contrary, rotation angle intervals in which the axial feed in relation to the rotation angle is zero or is even temporarily negative, that is to say its direction is reversed, are also possible.

[0211] In a preferred embodiment, this braking process takes place in defined partial steps, as will be explained in greater detail in the following.

[0212] In a manner which is in fact atypical or foreign to the mode of operation, this braking movement in the second working phase leads to the thread creation means now creating at least one encircling groove or peripheral groove or circumferential groove in the through-hole wall. The process in the second working phase may therefore also be referred to not only as a braking process but also as a countersinking movement or circumferential groove creation or peripheral groove creation or undercut movement, and, in the case of a tool with a purely cutting action, also as a free-cutting movement.

[0213] In the screw-out movement as the second reversing phase of the backward movement RB, following the first reversing phase of the acceleration movement BB, the axial feed and the rotary movement of the tool 300 are again synchronized with one another in accordance with the thread pitch P or 372 in order not to damage the thread, except that in each case the direction of the axial feed in the direction of the arrow of the backward movement RB is reversed or opposite to the direction of the arrow of the forward or working movement VB, and the direction of rotation of the rotary movement is likewise reversed, that is to say the backward direction of rotation is now set instead of the forward direction of rotation.

[0214] The thread axis or center axis of the thread with the thread groove 371 is designated by A and coincides with or is coaxial with the tool axis A of the tool 300 during the entire working movement, that is to say both in the first working phase and in the second working phase, and also during the reversing movement, that is to say both in the first reversing phase and in the second reversing phase.

[0215] FIGS. 4 to 6 each show, on the basis of a diagram, an exemplary embodiment of a process (or: method) or of a control sequence, which can be used both to create a thread in a previously created through-hole in the workpiece or to create a through-threaded hole in the workpiece, that is to say in the solid material of the workpiece without previous core drilling.

[0216] To create a thread in a preproduced through-hole, a thread-cutting tap or thread-forming tap according to the prior art mentioned at the outset can be used.

[0217] A combined drilling and thread-cutting tool, as known from DE 10 2016 008 478 A1 mentioned at the outset, or a combined drilling and thread-forming tool, as known from DE 10 2005 022 503 A1 mentioned at the outset, or a tool according to the invention, for example according to FIGS. 1 to 3, can be used to create a threaded hole.

[0218] In the diagram of FIG. 4, the penetration depth (or: vertical or axial coordinate) T is plotted on the vertical axis or ordinate as a measured coordinate for the axial feed in mm, which coordinate extends in the axial direction, that is to say along the tool axis A and the thread center axis, which is coaxial with the tool axis A. The values for the penetration depth T decrease downward from the value T=0 mm illustrated at the very top, which corresponds to the axial entry position at the workpiece surface of the workpiece 300 (as can be seen in FIGS. 1 to 3), and are therefore plotted downward as negative values. In the example of FIG. 3, by way of example, the numerical range is from T=0 mm to T=−18 mm.

[0219] The (summed) rotation angle φ of the rotary movement of the tool 300 about its tool axis A is plotted in degrees [° ] on the horizontal axis or abscissa. The rotation angle φ starts from the entry rotation angle or initial rotation angle φ=0° at the axial entry position T=0 mm at an entry point EP=(0, 0) and increases to the right toward positive values, up to the value of φ=8000° entered as the last value on the abscissa. The rotation angle φ increases toward positive values during the forward rotational movement or in a forward direction of rotation, and decreases during the backward rotary movement or in a backward direction of rotation opposite to the forward direction of rotation. In this case, ±360° corresponds to a complete revolution of the tool 300 about its tool axis A.

[0220] The graph of the function T (φ) according to FIG. 4 illustrates, in particular, the creation of a through-threaded hole, that is to say a complete threaded-hole creation cycle according to the invention, in an exemplary embodiment, without limiting generality.

[0221] The function T (φ) describes the dependence or synchronization of the axial feed movement in the axial coordinate (or: thickness of the workpiece) T on or with the rotary movement in the coordinate φ and is typically stored in a controller such as a numerical controller or CC controller of the machine tool, in particular in the form of a previously determined and stored value table or, alternatively, as a function for calculation in each case. According to the nomenclature customary in CNC technology, the T coordinate would correspond to the Z axis (spindle axis), where the positive direction is conventionally from the workpiece to the tool.

[0222] According to FIG. 4, the graph (φ;T (φ)) of the function T (φ) first runs through a linear segment typical of a thread-cutting tap or thread-forming tap and corresponding to the creation of the thread groove, i.e. in the form of a straight line, from the starting point p=0° and T=0 mm to a thread end point at φ.sub.0 and T(φ.sub.0)=−16 mm, at which the thread groove or the actual creation of the thread ends.

[0223] Thus, the representation of the linear function T (φ) in this segment from φ=0 to φ=φ.sub.0 and T=0 to T=−16 mm applies:

|T(φ)|=(P/360°)φ

[0224] with the thread pitch P.

[0225] The pitch or derivative dT/d.sub.φ in this region is constant and corresponds in absolute terms to P/360°. For the thread pitch, this means therefore

P=360° |dT/d.sub.φ|

[0226] Since, in the selected example of FIG. 4, the value for the thread depth corresponding to the entered angular value φ=3600° is T=−10 mm, the slope of the straight line is −1 mm/360° and thus the thread pitch is P=1 mm.

[0227] Owing to the axial feed along the workpiece thickness T or the thread center axis M being synchronized with the rotation, all the components of the tool 300 have traveled further by the thread pitch P or 372 during one complete revolution through 360°.

[0228] The linear segment of the function T (φ) corresponds to the usual synchronized kinematics of a thread-cutting tap or thread-forming tap and can be stored in a CNC controller, for example as an already fixedly programmed path condition (address letter G or G function), e.g. as G33, in particular G331 and G332, the thread pitch P being entered as an interpolation parameter parallel to the Z axis, typically under the address letter K in CNC nomenclature.

[0229] It is in this linear segment, that the thread creation process takes place, in particular to create the thread groove 371 in the first working phase according to FIG. 3, and a thread of thread depth T.sub.G is produced as the interval length of the penetration depth T, in particular from T=0 to T.sub.0, over the interval length or the rotation angle range φ.sub.G of the rotation angle φ, in particular from φ=0° to φ=φ.sub.0. In the example of FIG. 4, the thread creation process (first working phase) takes place from φ=0° to φ=.sub.0 and from the corresponding penetration depth T=0 mm to T=−16 mm.

[0230] The slope of the straight line in FIG. 4 between φ=0 and φ=T.sub.0 corresponds to the axial feed rate of the tool 2, which is synchronized with the rotation angle φ in accordance with the thread pitch P.

[0231] It is possible, in principle, for the time dependence of the rotation angle φ(t) as a function of time t and thus penetration depth T(t) as a function of time t to be varied during the thread creation process, even within wide ranges. Preferably, however, the speed of rotation dφ/dt and the axial feed rate dT/dt are in each case constant during the working movement VR. When the speed of rotation dφ/dt is changed, the axial feed rate dT/dt, that is to say the derivative of the penetration depth T with respect to time t, must therefore also be correspondingly adapted to ensure that the synchronization of the axial feed Z in accordance with the relationship Z=P/360° is maintained.

[0232] This is the known kinematics implemented in machine tool controllers or CNC controllers during thread creation by means of an axially operating threading tool such as a thread-cutting tap or thread-forming tap.

[0233] Following the thread creation process (first working phase), a braking process or a braking movement AB then takes place, in particular in the countersinking movement as the second working phase, in a rotation angle range ΔT between the rotation angle values φ.sub.0 and φ.sub.n and an associated penetration depth range ΔT, which, in the example in FIG. 4, extends from T(φ.sub.0)=−16 mm to T(φ.sub.n)=−17 mm. At the end of the braking movement AB, a reversal point UP is reached, at which the tool 300 comes to a brief stop both in terms of the rotary movement and in terms of the axial feed movement. At the reversal point UP, the maximum rotation angle range φ.sub.L for the creation of the threaded hole is reached, where φ.sub.L=φ.sub.G+Δφ, and the depth T.sub.L for the threaded hole, where T.sub.L=T.sub.G+ΔT.

[0234] During the braking process or the braking movement AB, the axial feed rate is reduced as a function of the rotation angle, said feed rate corresponding to the slope of the illustrated graph for the function T(φ), in accordance with a dependency or function which is preferably strictly monotonic (slope always decreasing) or monotonic (slope decreasing and, if appropriate, also zero in some segments), but, if appropriate, may also rise slightly again in some subsegments. Preferably, the slope is successively reduced in a predetermined number n of individual defined programmed or stored partial steps or braking steps S.sub.i, wherein the total number or number n is a natural number with n>1, in general 200>n>2, in particular 20>n>5, and wherein i is the count index for the braking step S.sub.i and is between 1 and n, i.e. 1≤i≤n.

[0235] In each partial step or braking step S.sub.i, a synchronization of the axial feed T (or of the feed rate dT/dt) and the rotation angle φ (or speed of rotation dφ/dt) in accordance with the control of a threading process is set or programmed in that an associated predetermined function T.sub.i (φ) with an associated value interval [T.sub.i−1, T.sub.i,] over the associated rotation angle interval [(φ.sub.i−1, φ.sub.i] is assigned or programmed to each braking step S.sub.i where 1≤i≤n.

[0236] The function T.sub.i(φ) is preferably linear, that is to say the graph is (ideally) a straight line.

[0237] In this case, the programmed or stored slope decreases stepwise or successively from one braking step S.sub.i to the next braking step S.sub.i+1, i.e. |dT.sub.i/d.sub.φ|>|dT.sub.i+1/d.sub.φ|. The slope in each case corresponds to a pitch parameter.

[0238] In an advantageous embodiment, this pitch parameter is programmed as a thread pitch in the CNC controller, that is to say in particular as an interpolation parameter along the z axis or the thread axis in a G33, in particular G331 and G332, path condition. As a result, it is possible to use the path conditions or G functions already specified in the control programming, and only the input parameter of the thread pitch has to be successively changed or reprogrammed.

[0239] Thus, in each braking step S.sub.i, the associated pitch parameter

P.sub.i=|dT.sub.i/d.sub.φ|

[0240] is programmed or set, wherein

P.sub.i+1<P.sub.i

[0241] for all i with 1≤i≤n. Furthermore,

P.sub.i<P

[0242] i.e. the pitch in the second working phase or during the braking movement AB is less than the thread pitch P during the first working phase. In particular, however, without limiting generality, P.sub.i=P (n−i)/n is possible. This applies, for example, for P.sub.1 to P.sub.n−1, wherein a value smaller than P.sub.n−1, e.g. P.sub.n−1/2, is then selected for P.sub.n.

[0243] In particular, P.sub.1 is chosen to be as close as possible to P. Furthermore, in particular P.sub.n>0 and is chosen to be as close as possible to 0.

[0244] The values of P.sub.i can be selected in such a way, for example, that a continuous movement into the free-cutting region is possible from the thread pitch movement. In particular, the speed of the tool should be maintained as far as possible. From this, various conditions can be formulated, for example, which can be mapped into approximation functions.

[0245] In each braking step S.sub.i, the following relationship holds for all i with 1≤i≤n:

T(φ)=T.sub.i−1−(P.sub.i/360°)(φ−φ.sub.i−1)

[0246] for φ∈[φ.sub.i−1, φ.sub.i] with the boundary conditions T(φ.sub.i−1)=T.sub.i−1 and T(φ.sub.i)=T.sub.i.

[0247] The rotation angle range Δφ for the braking movement AB in the second working phase is generally selected to be smaller than the rotation angle range φ.sub.G for thread creation in the first working phase, in particular Δφ<0.5 φ.sub.G and preferably Δφ<0.2 φ.sub.G is selected. This can depend, in particular, on the size of the usable thread length. Another influencing factor is the intended free-cutting function. If, in addition to pure braking, the intention is also to make further rotations for cutting free the chips, further revolutions can be added.

[0248] The penetration depth range (or: the maximum penetration depth) ΔT for the braking movement AB in the second working phase is generally selected to be smaller than the penetration depth range or the thread length T.sub.G for thread creation in the first working phase, in particular ΔT<0.5 T.sub.G, preferably ΔT<0.2 T.sub.G.

[0249] The penetration depth range ΔT for the braking movement AB can, in particular, be selected to be equal to P. Likewise, a penetration depth range ΔT of less than P is possible in order to keep the countersink or undercut smaller, for example 0.5 P or else 0.25 P. For reasons of machining, it may also be advantageous to select larger undercut heights or a larger penetration depth range ΔT, in particular up to 2 P and, in exceptional cases, even larger.

[0250] FIG. 5 now shows an exemplary embodiment of a braking movement AB in an enlarged view of the lower right-hand region of the diagram of FIG. 3 in a rotation angle range Δφ and an associated penetration depth range ΔT.

[0251] By way of example and without limiting generality, n=10 is selected in FIG. 5, and ten braking steps S.sub.1 to S.sub.10 with the associated pitch parameters P.sub.1 to P.sub.10 are thus shown.

[0252] The rotation angle range Δφ is accordingly divided into the n=10 rotation angle intervals [φ.sub.0, φ.sub.1], [φ.sub.1, φ.sub.2], . . . , [φ.sub.i−1, φ.sub.i], [φ.sub.i, φ.sub.i+1], . . . [φ.sub.9, φ.sub.10] and, associated with these intervals, the corresponding penetration depth intervals [T.sub.0, T.sub.1], [T.sub.1, T.sub.2], . . . , [T.sub.i−1, T.sub.i], [T.sub.i, T.sub.i+1], . . . , [T.sub.9, T.sub.10], into which the penetration depth range ΔT is divided, which in the example of FIG. 4 extends from T(φ.sub.0)=−16 mm to T(φ.sub.10)=−17 mm and/or corresponds to the thread pitch—P=−1 mm. A partial step S.sub.i corresponds to each interval.

[0253] In FIG. 5, unlike in FIG. 4, the differential rotation angle is plotted starting from φ.sub.0. If the intention is to enter the same values for φ on the rotation angle axis in FIG. 5 as in FIG. 4, then all the values on the horizontal axis must be added to the value of po, which in FIG. 4 is 5800°, for example. The braking movement AB begins at the rotation angle value φ.sub.0 and the associated penetration depth value T.sub.0 and ends at the final rotation angle value φ.sub.10 and the associated penetration depth value T.sub.10.

[0254] An associated pitch parameter P.sub.i, in particular in the form of a thread pitch or interpolation parameter of the CNC controller, is now assigned to each of these intervals of each braking step S.sub.i, that is to say the pitch P.sub.1 to the two intervals [φ.sub.0, φ.sub.1] and [T.sub.0, T.sub.i], the pitch P.sub.2 to the interval pair [φ.sub.1, φ.sub.2] and [T.sub.1, T.sub.2] and so on as far as the pitch P.sub.10 for the last interval pair [φ.sub.9, φ.sub.10] and [T.sub.9, T.sub.10].

[0255] The pitch values P.sub.1 to P.sub.10 are selected in such a way that P.sub.i+1<P.sub.i for i=1 to i=10 in FIG. 5 or n in FIG. 4. In each subsegment or braking step S.sub.i, the thread pitch P.sub.1 to P.sub.10 remains constant, resulting in substantially straight subsegments of the graph of the function T (φ), in which a synchronized “thread movement” takes place, that is to say the axial feed rate corresponds to the quotient of P.sub.i/360°.

[0256] In the exemplary embodiment illustrated in FIG. 5, the penetration depth intervals in the braking steps S.sub.i were selected to be of equal size for all i with 1≤i≤n (in this case, for example, n=10), so that the length of the intervals T.sub.1−T.sub.0=T.sub.2−T.sub.1=T.sub.1−T.sub.i−1=T.sub.i+1−T.sub.i=T.sub.n−T.sub.n−1 is selected to be equal or equidistant, i.e.

T.sub.i−T.sub.i−1=ΔT/n

[0257] in the illustrated exemplary embodiment of FIG. 5, is selected as −1 mm/10=−0.1 mm.

[0258] Since the axial feed is selected to be constant in each subsegment or subinterval in the exemplary embodiment of FIG. 5 since T.sub.i+1−T.sub.i is selected to be equal or equidistant for all i, as the pitch P.sub.i becomes smaller and thus the axial feed rate decreases, there are greater rotation angle intervals φ.sub.i+1−φ.sub.i

φ.sub.i+1−φ.sub.i>φ.sub.i−φ.sub.i−1

[0259] in the rotation angle range Δφ in the braking steps S.sub.i. That is to say that the rotation angle distance φ.sub.2−φ.sub.1 is smaller than the rotation angle distance φ.sub.3−φ.sub.2, and the rotation angle distance φ.sub.i+1−φi is larger than the angular distance φ.sub.i−φ.sub.i−1. The last subsegment between the rotation angle values φ.sub.10−φ.sub.9 covers the largest angular distance or angular range. This corresponds to a continuous braking process which is slowed down in each subsegment or braking step S.sub.i.

[0260] During the braking movement AB, the time dependence of the speed of rotation dφ/dt and the axial feed rate dT/dt are selected or controlled or programmed in such a way that the tool 300 comes to rest at the reversal point UP=(φ.sub.n, T.sub.n) or (φ.sub.10, T.sub.10), that is to say dφ/dt=0 and dT/dt=0 at φ=φ.sub.n or T=T.sub.n or at φ=φ.sub.10 or T=T.sub.10.

[0261] The reduction of the speed of rotation dφ/dt and of the axial feed rate dT/dt to 0 as a function of the time t can take place, for example, continuously during the braking movement AB or even, for example, only in the last braking step S.sub.n or S.sub.10.

[0262] The curves of the graphs in braking steps S.sub.1 to S.sub.10 of FIG. 5, which are in reality not exactly linear but somewhat rounded, follow physically from the inertia of the drive system, in particular of the controller, including its interpolation routines for smoothing the transitions, and of the machine drives and the mass inertia of the moving components.

[0263] However, when shown in an idealized manner or stored in the programming of the braking movement itself, the described sequence of linear functions or linear segments arranged in series with a slope decreasing in steps, i.e. a feed rate which decreases in steps and is respectively constant, is obtained in the individual braking steps S.sub.i, e.g. S.sub.1 to S.sub.10.

[0264] Before initiating a retraction or reversing movement, an intermediate step, such as a cleaning process, may optionally be carried out. Here, for example, chip root residues can be removed by further rotation of the tool or the circumferential groove can be cleaned of residues of the thread tips in order to obtain a cleaner cylindrical region. A screw could then be screwed in even better.

[0265] In one embodiment, as shown in particular in FIG. 4 and FIG. 6, after the reversal point UP is reached, a reversing movement or backward movement RB is then initiated, which initially comprises an acceleration movement BB in a first reversing phase up to introduction into the thread groove and, in a second reversing phase, a backward movement RR, in which the tool 300 is extracted outward in a manner synchronized by the thread groove.

[0266] In an advantageous embodiment, the control curve or function according to FIG. 4 can be used or traversed in the reverse order.

[0267] The rotary movement is reversed for the backward movement from the forward direction of rotation to the backward direction of rotation, i.e. the rotation angle φ is preferably reduced, starting from φ=φ.sub.n or φ=φ.sub.10 at the reversal point UP or is rotated back in the negative direction until finally the initial value p=0 is reached again and the tool 300 emerges from the workpiece. The dependence or function T(φ), which is preferably assumed unchanged, then leads to the penetration depth T becoming smaller in terms of magnitude as the rotation angle decreases, that is to say decreasing again from T=T.sub.n or T=T.sub.10 at the reversal point UP to T=0 at the entry point EP at φ=0, which is thus at the same time also the exit point. In particular, the first reversing phase corresponds to the second working phase and the second reversing phase corresponds to the first working phase.

[0268] In particular, it is also possible to use an embodiment for the second working phase, such as, for example, according to FIG. 5, in reverse order for the first reversing phase.

[0269] FIG. 6 shows an exemplary embodiment of how, in the first reversing phase, starting from the reversal point UP, the same dependency or function T(φ) can be used in the opposite order for the acceleration movement BB in reversal of the braking movement AB, for example according to FIGS. 4 and 5.

[0270] However, it is also possible to use other functions T(φ) and partial steps than in FIG. 6 which preferably lead back to the point (φ.sub.0, T.sub.0) at which the braking movement AB also began or the first working phase ended, thus enabling the correct introduction point for the tool to be reached for the return movement through the thread groove.

[0271] Preferably, in reverse order starting from the final angle value φ.sub.n or φ.sub.10, an acceleration phase is first carried out as the first reversing phase with an acceleration movement BB with the same incremental steps. However, these steps are now acceleration steps S; with n+1≤j≤2 n, in FIG. 5 starting with S.sub.11 to S.sub.20 for n=10.

[0272] Associated with each of these acceleration steps S.sub.j is an associated rotation angle interval [(φ.sub.10, φ.sub.11], [φ.sub.11, φ.sub.12], . . . , [φ.sub.j−1, φ.sub.j], [φ.sub.j, φ.sub.i+1], . . . [φ.sub.19, φ.sub.20], where p from the first reversal phase simply corresponds to ei from the second working phase if i+j=n is set. The pitch parameters likewise remain the same, only in the reverse order, i.e. in FIG. 6 they are traversed from right to left from P.sub.10 via P.sub.9 and P.sub.8 to P.sub.1 for the subsegments of the control curve according to FIG. 5, until the depth value T.sub.0 is reached. According to FIG. 6, the new angle value φ.sub.11 is assumed later in time than angle value φ.sub.10, and the interval [φ.sub.10, φ.sub.11] corresponds to the interval [T.sub.10, T.sub.9] with the thread pitch P.sub.10, and the subsequent angle interval [φ.sub.11, φ.sub.12] corresponds to the penetration depth interval [T.sub.9, T.sub.8] with the corresponding thread pitch P.sub.9, etc., up to the last subsegment of [φ.sub.19, φ.sub.20] corresponding to [T.sub.1, T.sub.0] with the thread pitch P.sub.1.

[0273] Subsequently, in the reverse direction to FIG. 4, the linear segment of the curve is traversed from φ.sub.0 to φ=0, corresponding to the penetration depth T from T.sub.0 to T=0. The corresponding axial feed rate in the backward movement is now again P/360° in the opposite direction. As a result, the tool is guided precisely the other way round through the thread created in the forward movement, without damage to the thread groove created occurring in the thread. The backward movement is thus synchronized exactly as the forward movement, only with the reverse direction of rotation, with the result that the value φ of the angle φ.sub.n just decreases backward again to φ=0, and the thread depth now increases mathematically from T=T.sub.0 to T=0, even though the axial feed rate is reversed.

[0274] Using the same control curve or function T(φ) as in the forward movement VR in the two working phases, including the two reversing phases in the backward movement RR, has the advantage, on the one hand, that the tool 300 can be controlled in a positionally accurate or motionally accurate manner and is located in the correct position, particularly during introduction into the thread groove, and in this way the forces during reversing can be kept very low and/or a high reversing or retraction speed is made possible.

[0275] In one embodiment of an implementation of the described dependencies or functions for T(φ), the values of the penetration depth T are used as input parameters measured or predefined by the controller or programming, and the associated values of the rotation angle φ are obtained from the dependency by means of the associated pitch parameters P and P.sub.i.

[0276] Thus, a CNC program for thread cutting or thread forming can be selected, in particular with a G33, in particular G331 and G332, path condition with a thread pitch to be entered, and a sequence or quantity of values for the penetration depth can now be specified in which a changeover is made to a new thread pitch parameter, the thread pitch parameter being maintained up to the next value of the penetration depth.

[0277] A sequence would be, for example,

[0278] Working Movement:

[0279] At penetration depth T=0, select the thread pitch parameter P and maintain this until T=T.sub.0. A speed of rotation or rotational speed is set.

[0280] At T=T.sub.0, change to thread pitch parameter P.sub.1 and maintain this until T=T.sub.1.

[0281] At T=T.sub.i, change to thread pitch parameter P.sub.i+1 and maintain this until T=T.sub.i+1 for all i with 1≤i≤n.

[0282] Reduce the rotational speed or speed of rotation to 0 at T=T.sub.n.

[0283] and preferably for the reversing movement:

[0284] At T=T.sub.n, reverse the axial feed movement and the rotary movement at a set speed of rotation or rotational speed and start again in each case in the opposite direction with thread pitch parameter P.sub.n and maintain this until T=T.sub.n−1.

[0285] At T=T.sub.j, change to thread pitch parameter P; and maintain this until T=T.sub.j−1 for all j as descending index with 1≤j≤n−1.

[0286] At T=T.sub.0, select thread pitch parameter P and maintain this until T=0.

[0287] Even if this embodiment of the working movement in the second working phase and/or reversing movement in the first reversing phase, which in particular corresponds to a linear interpolation, has advantages due to its simple implementation in existing machine programs, it is also possible according to the invention to provide other dependencies or functions or interpolations in individual partial steps or partial intervals for the relationship between T and p or combinations thereof in all the embodiments.

[0288] With the linear interpolation described, in particular according to FIGS. 5 and 6, the linear curve segments or graph segments are appended continuously to one another, i.e. the starting points (φ.sub.i, T.sub.i) of each interval correspond to the end points of the respectively preceding interval and, in the case of the first interval, to the end point (φ.sub.0, T.sub.0) of the linear graph of thread creation. These connection points are also referred to as interpolation points.

[0289] In all embodiments or interpolations, it is also possible, instead of linear segments, to select curve segments or graph segments which are appended (or: linked, connected) to one another in a continuously differentiable manner. This means that not only does the starting point of each interval coincide with the end point of the preceding interval, that is to say there is a continuous transition at the connection points between the intervals, but in addition the graph segments or their functions can also be differentiated at these connection points and their derivatives have the same value. As a result, smooth or continuously differentiable transitions between the graphs are achieved in the individual braking steps or intervals, which is conducive to the motion sequence. The transition at the rotation angle φ.sub.0 from the thread creation movement in the first working phase to the braking movement AB in the second working phase, or then correspondingly preferably also from the first reversing phase to the second reversing phase, is preferably continuously differentiable or selected with the same slope.

[0290] Examples of functions which are suitable for such a continuously differentiable interpolation are polynomials of a degree higher than 1, in particular of the third degree, such as, for example, cubic splines.

[0291] Spline interpolation can be used here. Using a 3.sup.rd degree polynomial function as spline function

T(φ)=a.sub.3φ.sup.3+a.sub.2φ.sup.2+a.sub.1φ+a.sub.0

[0292] with the boundary conditions customary in spline interpolation, it is possible, for example, to create a function which is continuous as far as the third derivative.

[0293] Furthermore, it is also possible to use a continuous function, in particular a function which falls strictly monotonically or else monotonically, for the braking process or at least a predominant part of the braking steps S.sub.i, e.g. an exponential function or logarithmic function.

[0294] In a further embodiment of an implementation of the described dependencies or functions for T(φ), the values of the rotation angle φ are used as input parameters measured or predefined by the controller or programming, and the associated values of the penetration depth T are obtained from the dependency by means of the pitch parameters P and P.sub.i.

[0295] In a third variant, it is also possible for the time to be predefined as an input parameter, and the values of the rotation angle φ(t) and of the penetration depth T(t) are obtained from the dependency on the time t and the dependency on one another by means of the pitch parameters P and P.sub.i.

[0296] In one embodiment, control or synchronization can take place in an open regulating or control circuit without measuring the process variables penetration depth and rotation angle. In this case, a penetration depth value is assigned to each rotation angle value by means of a value table or by calculation according to the stored formulas, and the rotary drive and axial drive are controlled in a corresponding manner.

[0297] In a further embodiment, a measurement of at least one of the two process variables penetration depth and rotation angle can also be carried out and the measured values can be fed back into the controller in order to implement control according to the desired curve shown in FIG. 4 in a closed control loop. The rotation angle φ is as a rule determined in the region of the drive, in particular of the drive spindle, by means of rotation angle sensors or measurement of physical variables which have a clear relationship to the rotation angle. However, it is also possible in principle to measure the rotation angle directly at the tool 100, 200, 300. The penetration depth T can be measured by axial position sensors and, here again, generally at the drive, in particular the drive spindle, or else, in a special embodiment, at the tool or workpiece itself.

[0298] FIG. 7 to FIG. 10 show contours of revolution which are formed by the end and/or main cutting edges or thread creation means.

[0299] The thread-cutting teeth in FIG. 7 to FIG. 10 are arranged on the end and/or main cutting edges, in particular on each end and/or main cutting edge. The thread-cutting teeth are integral with the end and/or main cutting edges.

[0300] The thread-cutting teeth in FIG. 7 to FIG. 10 are preferably arranged on the tap bodies, in particular on each tap body. The thread-cutting teeth are integral with the tap bodies.

[0301] Here, FIG. 7 shows a contour of revolution created by three end and/or main cutting edges or thread creation means, in particular on the tap bodies. In this case, the first end and/or main cutting edge or the first tap body forms thread-cutting teeth 411 and 412. The second end and/or main cutting edge or the second tap body forms thread-cutting teeth 421 and 422. The third end and/or main cutting edge forms thread-cutting tooth 431.

[0302] The first thread-cutting tooth 411 of the first end and/or main cutting edge or of the first tap body and the second thread-cutting tooth 421 of the second end and/or main cutting edge or of the second tap body jointly form the contour of revolution for the countersink 401, at an angle 470 of 30°.

[0303] The second thread-cutting tooth 421 is at a distance 472 from the third thread-cutting tooth 431 along the countersink profile 401.

[0304] On the outside of the third thread-cutting tooth 431 and of each thread-cutting tooth following this end and/or main cutting edge, the contour of revolution has a width 471 which corresponds to the thread pitch of the thread-cutting tooth along the outside of the end and/or main cutting edge.

[0305] FIG. 8 shows a contour of revolution created by four end and/or main cutting edges or thread creation means, in particular on the tap bodies. The first thread-cutting tooth 511 of the first end and/or main cutting edge or of the first tap body and the second thread-cutting tooth 521 of the second end and/or main cutting edge or of the second tap body jointly form the contour of revolution for the countersink 501, at an angle 570 of 30°. The third thread-cutting tooth 531 of the third end and/or main cutting edge or of the third tap body jointly forms the contour of revolution for the countersink 501, at an angle 570 of 30°.

[0306] There is no spacing between the second thread-cutting tooth 521 and the third thread-cutting tooth 531 along the countersink profile 501.

[0307] FIG. 9 shows a contour of revolution created by five end and/or main cutting edges or five thread creation means. The first thread-cutting tooth 611 of the first end and/or main cutting edge and the second thread-cutting tooth 621 of the second end and/or main cutting edge jointly form the contour of revolution for the countersink 601, at an angle 670 of 30°. The third thread-cutting tooth 631 of the third end and/or main cutting edge and the fourth thread-cutting tooth 641 of the fourth end and/or main cutting edge jointly form the contour of revolution for the countersink 601, at an angle 670 of 30°.

[0308] FIG. 10 shows a contour of revolution created by six end and/or main cutting edges or six thread creation means. The first thread-cutting tooth 711 of the first end and/or main cutting edge and the second thread-cutting tooth 721 of the second end and/or main cutting edge jointly form the contour of revolution for the countersink 701, at an angle 770 of 30°. The third thread-cutting tooth 731 of the third end and/or main cutting edge and the fourth thread-cutting tooth 741 of the fourth end and/or main cutting edge jointly form the contour of revolution for the countersink 701, at an angle 770 of 30°.

[0309] Each of the thread creation means 163, 263, 363, 400, 500, 600, 700 has a respective contour of revolution or can have a contour of revolution.

[0310] In particular, the contour of revolution forms a cutting edge contour for the at least one countersink. In particular, the contour of revolution forms an envelope curve and/or envelope contour, wherein the envelope curve and/or envelope contour are/is formed by the countersink cutting edges.

[0311] An envelope curve and/or envelope contour and/or contour of revolution is, in particular, the envelope curve and/or envelope contour and/or contour of revolution and/or contour obtained when the tool is rotated about its tool axis.

[0312] The end region 117, 217, 317 in each case comprises a drilling region for drilling a through-hole.

[0313] The drilling region comprises at least two end and/or main cutting edges, on at least two tap bodies, for creating the through-hole, which extend into the thread creation region for creating the through-thread.

[0314] Flutes extend in each case between the end and/or main cutting edges through the thread creation region 116, 216, 316 and into the at least one flute or neck region 112, 212, 312.

[0315] The at least two end and/or main cutting edges form the countersink cutting edges and/or the contour of revolution on the outside diameter.

[0316] The tool, in particular the thread creation means, is designed in such a way that it has or creates an at least substantially closed envelope curve and/or envelope contour.

[0317] In particular, the tool is designed in such a way that it has or creates a closed envelope curve and/or envelope contour.

[0318] The tool has at least three end and/or main cutting edges, in particular, according to FIG. 8, at least four end and/or main cutting edges, preferably, according to FIG. 10, at least five end and/or main cutting edges.

[0319] The countersink has a countersink angle 470, 570, 670, 770 which is greater than 25° and less than 60°, preferably between 30° and 45°, in particular at least substantially 30°.

[0320] The envelope curve and/or envelope contour 401, 501, 601, 701 are/is formed by at least one first end and/or main cutting edge 411, in particular a first shank-side thread-cutting tooth, as a first countersink cutting edge and a second end and/or main cutting edge 421, in particular a second shank-side thread-cutting tooth, as a second countersink cutting edge, which, in particular jointly, form a closed envelope curve and/or envelope contour 401, 501, 601, 701 during rotation.

[0321] The envelope curve and/or envelope contour 401, 501, 601, 701 are/is conical, particularly in the countersinking region.

[0322] The first shank-side thread-cutting tooth 411 and the second shank-side thread-cutting tooth 421 are ground down in such a way with respect to the further thread-cutting teeth of the end and/or main cutting edges that the envelope curve and/or envelope contour of the first shank-side thread-cutting tooth forms the innermost ring of the at least one countersink with the countersink angle, and that the envelope curve and/or the envelope contour of the second shank-side thread-cutting tooth forms the second-innermost ring, surrounding the innermost ring, of the at least one countersink with the countersink angle.

[0323] The second-innermost ring directly surrounds the innermost ring of the at least one countersink and thus at least partially forms the conical countersink 402, 501, 601, 701.

LIST OF REFERENCE SIGNS

[0324] 100, 200, 300 tool [0325] 211 shank region [0326] 112, 212, 312 first neck region [0327] 215 first conical region [0328] 214 second neck region [0329] 213 second conical region [0330] 116, 216, 316 thread creation region, thread creation means [0331] 117, 217, 317 end region [0332] 120, 220, 320 end face [0333] 130, 230, 330 tap body [0334] 132, 232, 332 flute [0335] 134, 234, 334 tap body [0336] 136, 236, 336 flute [0337] 150, 250, 350 workpiece [0338] 151, 251, 351 first workpiece side [0339] 152, 252, 352 second workpiece side [0340] 218 guide region [0341] 262 second countersink [0342] 163, 263, 363 through-thread [0343] 164, 264, 364 first countersink [0344] 171, 271, 371 thread profile [0345] 172, 272, 372 thread pitch [0346] 400,500,600,700 thread creation means [0347] 401,501,601,701 envelope curve, countersink profile [0348] 470,570,670,770 countersink angle [0349] 471,472 distances [0350] 411,412,421,422,431 thread-cutting teeth, thread-cutting tooth contours [0351] 511,521,531 thread-cutting teeth, thread-cutting tooth contours [0352] 611,621,631,641 thread-cutting teeth, thread-cutting tooth contours [0353] 711,721,731,741,751 thread-cutting teeth, thread-cutting tooth contours [0354] r radial deflection [0355] A tool axis [0356] V feed [0357] VR forward direction [0358] RR backward direction [0359] α rotation angle [0360] P11, P21, P31 first position [0361] P12, P22, P32 second position [0362] P13, P23, P33 second position [0363] AB braking movement [0364] BB acceleration movement [0365] M thread center axis [0366] P thread pitch [0367] P.sub.1 to P.sub.10 pitch parameters [0368] S.sub.1 to S.sub.10 braking step [0369] S.sub.11 to S.sub.20 acceleration step [0370] T penetration depth [0371] T.sub.G thread depth [0372] T.sub.L threaded hole depth [0373] T.sub.0 to T.sub.10 depth value [0374] T.sub.i, T.sub.n depth value [0375] ΔT penetration depth range [0376] UP reversal point [0377] VB forward movement [0378] RB backward movement [0379] φ summed rotation angle [0380] Δφ rotation angle range [0381] φ.sub.0 to φ.sub.20 rotation angle value [0382] φ.sub.i, φ.sub.n rotation angle value [0383] δ thread pitch angle