Method for Manufacturing a Continuous Drill Ring for a Core Drill Bit

Abstract

A method for manufacturing a continuous drill ring for a core drill bit is disclosed. The method includes forming at least two green compacts in layers in a direction of formation between a bottom side and a top side by successively applying powder layers containing a powder mixture and diamond layers containing diamond particles that are arranged in a set pattern, shaping the green compacts into ring segments under the effect of pressure, sintering the ring segments under the effect of heat, and combining the sintered ring segments in a circular manner and joining the same in a frictionally engaging or integrally bonding manner at the lateral edges thereof so as to obtain the continuous drill.

Claims

1.-12. (canceled)

13. A method for manufacturing a continuous drill ring for a core drill bit, comprising the steps of: forming at least two green compacts by successive application of powder layers of a powder mixture and diamond layers having diamond particles; forming the at least two green compacts under an effect of pressure into ring segments; sintering the ring segments under an effect of temperature; and assembling the sintered ring segments in a circular shape and joining the sintered ring segments to each other at respective side edges by frictional engagement or integral bonding to form the continuous drill ring.

14. The method according to claim 13, wherein the ring segments are subjected to an effect of pressure during the sintering.

15. The method according to claim 14, wherein the ring segments are externally shaped by the effect of pressure during the sintering.

16. The method according to claim 13, wherein the ring segments include first ring segments and second ring segments and wherein the first and the second ring segments are disposed along a peripheral direction of the continuous drill ring in an alternating successive manner.

17. The method according to claim 16, wherein the first ring segments are formed of a first powder mixture and first diamond particles and wherein the second ring segments are formed of a second powder mixture and second diamond particles.

18. The method according to claim 13, wherein the ring segments are formed from identical green compacts and wherein the ring segments include first ring segments having a convex curvature and second ring segments having a concave curvature.

19. The method according to claim 18, wherein a top side of the green compacts for the first ring segments is disposed on an exterior side and a top side of the green compacts for the second ring segments is disposed on an interior side and wherein the first and the second ring segments are arranged along a peripheral direction of the continuous drill ring in an alternating successive manner.

20. The method according to claim 19, wherein a number of diamond layers and a size of the diamond particles are adjusted such that an average diamond diameter of the diamond particles amounts to at least 45% of a ratio of a width of the continuous drill ring to the number of diamond layers.

21. The method according to claim 13, wherein the green compacts are formed of powder layers with rectangular base surfaces.

22. The method according to claim 13, wherein the green compacts are formed of powder layers with pentagonal base surfaces and wherein the base surfaces have a rectangle and a trapezoid with two right interior angles.

23. The method according to claim 13, wherein the green compacts are formed of powder layers with hexagonal base surfaces and wherein the base surfaces have a rectangle and an equal-sided trapezoid.

24. The method according to claim 22, wherein a height of the trapezoid is between ⅓ and ⅚ of a total height of the green compacts.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1 depicts a core drill bit consisting of a drill ring, a cylindrical drill shank, and a receiver section;

[0033] FIGS. 2A-C depict a first embodiment of a drill ring according to the invention, which is formed of four ring segments, in a three-dimensional illustration (FIG. 2A), in a cross-section perpendicular to the cylinder axis of the drill ring (FIG. 2B), and in a detail enlargement (FIG. 2C);

[0034] FIG. 3 depicts a second embodiment of a drill ring according to the invention, which is formed of four ring segments with water slits;

[0035] FIGS. 4A-C depict the manufacture of the drill ring of FIG. 3 out of four identical green compacts with a hexagonal base surface (FIG. 4A), wherein two green compacts are formed and sintered into concave first ring segments and two green compacts are formed and sintered into convex second ring segments (FIG. 4B), and the sintered ring segments are arranged along a peripheral direction in an alternating successive manner and are joined at the side edges in a frictionally engaging or integrally bonding manner to obtain a continuous drill ring (FIG. 4C); and

[0036] FIGS. 5A-C depict green compacts with a rectangular base surface (FIG. 5A), a pentagonal base surface (FIG. 5B) and a hexagonal base surface (FIG. 5C).

DETAILED DESCRIPTION OF THE DRAWINGS

[0037] FIG. 1 depicts a core drill bit 10 with a drill ring 11, a cylindrical drill shank 12, and a receiver section 13 with insertion end 14. Core drill bit 10 is attached via insertion end 14 in the tool chuck of a core drill device and in drilling operations, it is driven by the core drill device in a rotation direction 15 about a rotation axis 16, wherein rotation axis 16 runs coaxially to the cylinder axis of core drill bit 10.

[0038] Drill ring 11 is welded, soldered, or screwed to drill shank 12, or attached by some other suitable attachment method to drill shank 12. To weld drill ring 11 to drill shank 12, the joining region between drill ring 11 and drill shank 12 must be formed of a weldable material and may not contain any diamond particles, since diamond particles are not weldable.

[0039] FIGS. 2A-C depict a first embodiment of a drill ring 21 according to the invention, which is composed of multiple ring segments and can replace drill ring 11 of core drill bit 10 of FIG. 1. FIG. 2A thus depicts drill ring 21 in a three-dimensional view; FIG. 2b depicts drill ring 21 in a cross-section perpendicular to rotation axis 16; and FIG. 2C depicts a section from the cross-section of FIG. 2B in the joining region between two ring segments.

[0040] Drill ring 21 is composed of four ring segments, which are joined to each other at the side edges and form a continuous ring in the peripheral direction (FIG. 2A). The ring segments of drill ring 21 can be subdivided into two first ring segments 22.1, 22.2, and two second ring segments 23.1, 23.2, which are arranged along the peripheral direction of drill ring 21 in an alternating successive manner. First ring segments 22.1, 2.2 consist of a first powder mixture 24 and first diamond particles 25; and second ring segments 23.1, 23.2 consist of a second powder mixture 26 and second diamond particles 27 (FIG. 2B).

[0041] FIG. 2C depicts a section of the cross-section from FIG. 2B in the joining region between first ring segment 22.1 and second ring segment 23.1. First ring segment 22.1 is formed of a number of m.sub.1 powder layers of first powder mixture 24 and m.sub.1 diamond layers of first diamond particles 25. Second ring segment 23.1 is formed of a number of m.sub.2 powder layers of second powder mixture 26 and m.sub.2 diamond layers of second diamond particles 27. In the embodiment of FIG. 2, first ring segment 22.1 has m.sub.1=3 powder layers 28.1, 29.1, 30.1 and m.sub.1=3 diamond layers 32.1, 33.1, 34.1; and second ring segment 23.1 has m.sub.2=3 powder layers 35.1, 36.1, 37.1 and m.sub.2=3 diamond layers 38.1, 39.1, 40.1.

[0042] First diamond particles 25 of diamond layers 32.1-34.1 are arranged on three circular first removal paths 42.1, 43.1, 44.1 having various first curvature radii R.sub.1i, i=1, 2, 3. Second diamond particles 27 of diamond layers 38.1-40.1 are arranged on three circular second removal paths 45.1, 46.1, 47.1 having various second curvature radii R.sub.2i, i=1, 2, 3. Selecting the materials for the first and second powder mixture 24, 26, selecting the diamond distribution and size for first and second diamond particles 25, 27, and the number m.sub.1, m.sub.2 of the diamond layers and removal paths enable one to adapt drill ring 21 to various substrates to be machined.

[0043] Ring segments 22.1, 22.2, 23.1, 23.2 are formed layer-wise from three powder layers and three diamond layers. In the layer-wise formation, the powder mixture is filled into a die and forms the first powder layer. The diamond particles are placed in a placement pattern as the first diamond layer on or in the first powder layer. To compress the layer structure, an interim compression may occur after placing the diamond particles. Subsequently, the powder mixture is filled into the die and forms the second powder layer. The diamond particles are placed in a placement pattern as the second diamond layer on or in the second powder layer. This process is repeated until the desired formation height of the green compact is achieved. A diamond layer is used as the last layer.

[0044] FIG. 3 depicts a second embodiment of a drill ring 51 according to the invention, which consists of four ring segments and can replace drill ring 11 of core drill bit 10. Between the ring segments, there are designed four water slits 52.1, 52.2, 52.3, 52.4, by means of which a cooling fluid can be carried to the cutting location. The ring segments are arranged in such a manner that drill ring 51 has diamond-studded region 55 and a diamond-less region 56 in an alternating manner on interior side 53 and on exterior side 54.

[0045] Water slits 52.1-52.4 extend over a height of approx. ⅔ of the total height of drill ring 51. To ensure the functional capability of drill ring 51 when water slits 52.1-52.4 are eroded, two ring segments have a hole 57.1, 57.2 by means of which cooling fluid can be carried to the machining location.

[0046] FIGS. 4A-C depict the manufacture of drill ring 51 from four identical green compacts 61 having a hexagonal base surface (FIG. 4A). Two green compacts 61 are formed and sintered into concave first ring segments 62 and two green compacts 61 are formed and sintered into convex second ring segments 63 (FIG. 4B). The sintered first and second ring segments 62, 63 are combined in a circular manner and joined at the side edges in a frictionally engaging or integrally bonding manner to obtain a continuous drill ring 51 (FIG. 4C).

[0047] FIG. 4A depicts the formation of green compact 61, which was manufactured in layer-wise manner out of powder layers of a powder mixture 64 and diamond layers of diamond particles 65. Green compact 61 consists of a joining region 66, which is also referred to as foot zone, and machining region 67, which is also referred to as matrix zone. Joining region 66 and machining region 67 may be formed jointly in a layer-wise manner, wherein no diamond particles 65 may be placed in the joining region. Alternatively, the joining region may be manufactured as a separate region, and it may be joined to the machining region during sintering.

[0048] The base surface of green compact 61 is designed in a hexagonal manner and consists of a rectangle 68 and an adjoining even-sided trapezoid 69, wherein joining region 66 of green compact 61 is situated in rectangle 68. In the region of the trapezoid sides, water slits 52.1-52.4, by means of which the cooling fluid is carried to the machining location, are formed during sintering by means of the additional application of pressure. Height h of trapezoid 69 in the green compress determines the height of water slits 52.1-52.4. In the embodiment, height h of trapezoid 69 corresponds to half the total height H of green compact 61.

[0049] FIG. 4B depicts first ring segment 62, which was produced with a convex curvature out of green compact 61 of FIG. 4A under the effects of temperature and pressure, and second ring segment 63, which was produced with a concave curvature out of green compact 61 of FIG. 4A under the effects of temperature and pressure. The effect of temperature ensures that powder mixture 64 sinters in ring segments 62, 63. By means of the effect of pressure in an axial direction, i.e., parallel to the cylinder axis of the drill ring, there results a compression of the ring segments, which leads to a compression of ring segments 62, 63. The hot pressing occurs in a die, which establishes the final shape of ring segments 62, 63.

[0050] For first ring segment 62, the top side of green compact 61, which is designed as a diamond layer, is arranged on exterior side 54, and for second ring segment 63, the top side of green compact 61 is arranged on interior side 53. Sintered first ring segment 62 has a first and second side edge 71, 72, which are joined to a first and second side edge 73, 74 of sintered second ring segment 63. In doing so, first side edge 71 of first ring segment 62 is joined to second side edge 74 of second ring segment 63, and second side edge 72 of first ring segment 62 is joined to first side edge 73 of second ring segment 63. For drill ring 51 having two first and second ring segments 62.1, 62.2, 63.1, 63.2, in each case the first and second side edges of adjoining ring segments are joined to each other.

[0051] FIG. 4C depicts first ring segments 62.1, 62.2 and second ring segments 63.1, 63.2, which are arranged along a peripheral direction of drill ring 51 in an alternating successive manner and are joined at the side edges in a frictionally engaging or integrally bonding manner. Ring segments 62.1, 63.1, 62.2, 63.2 form a continuous drill ring. All conventional joining processes, such as welding, soldering, adhesive bonding, and comparable joining methods are suitable as methods for frictional or integral bonding.

[0052] In the method according to the invention, a drill ring is formed of a plurality of green compacts, which are shaped into ring segments and sintered into a continuous drill ring; polygonal base surfaces are suitable as geometries for the green compacts. FIGS. 5A-C depict green compacts 81 having a rectangular base surface (FIG. 5A), green compacts 82 having a pentagonal base surface (FIG. 5B), and green compacts 83 with a hexagonal base surface (FIG. 5C).

[0053] Rectangular surface 84 of green compacts 81 represent the simplest geometry to manufacture drill rings from a plurality of ring segments. In the embodiment of FIG. 5A, three identical green compacts 81.1, 81.2, 81.3 are used to manufacture a continuous drill ring.

[0054] The pentagonal base surface of green compacts 82 can be subdivided into a rectangle 85 and a trapezoid 86 with two right interior angles. In the region of the slanted trapezoid side, a water slit 87 is produced with the adjoining ring segment during sintering. With such a pentagonal base surface, a number of n water slits 87 is produced on a drill ring having 2n, n≧1 ring segments.

[0055] The hexagonal base surface of green compacts 83 can be subdivided into a rectangle 88 and an equal-sided trapezoid 89. In the region of the slanted trapezoid sides, a water slit 90 is produced with the adjoining ring segment during sintering. With such a hexagonal base surface, a number of n water slits 90 is produced on a drill ring having n, n≧2 ring segments.