JP4484981B2 - Core drill and core drill device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a core drill and a core drill device for drilling a hard material such as a ceramic material, a semiconductor single crystal material, a glass material, a quartz material, a stone material, an asphalt material, and a concrete material.
[0002]
[Related technologies]
As shown in FIG. 5, the conventional core drill 12 includes a cup-shaped base 16 made up of a disk-like upper wall 16 a and a cylindrical side wall 16 b at the tip of a steel shank 14 that acts as a rotating shaft. A grindstone portion 18 having diamond or CBN abrasive grains fixed thereto by metal bond, resin bond, electrodeposition or the like is attached to the tip portion of the gold portion 16, and the shank 14 and the base metal portion 16 are connected by driving means such as a motor. The tool is configured such that by rotating the grindstone portion 18 and bringing the grindstone portion 18 into contact with the workpiece W, the workpiece W can be ground into a circular shape so as to open a hole. The shank 14 of the core drill 12 is provided with an axial through hole 22 for supplying the grinding fluid 20 to the grinding region. For example, when the grinding liquid 20 is supplied to the shaft center through hole 22 when grinding the workpiece W such as glass, the grinding liquid 20 is used for the tip surface and inner and outer peripheral surfaces of the grindstone 18 and the workpiece W. While passing through the gap between the surface to be ground, the grinding area is cooled, and the swarf of the workpiece W and the abrasive grains that have fallen off (hereinafter sometimes referred to as swarf etc.) are washed away together. Discharged to the outside. Thereby, the excavation speed of the core drill 12 is increased and the life of the grindstone 18 is extended.
[0003]
However, when drilling a workpiece W such as relatively thick glass using the conventional core drill 12, if the grinding depth increases as the grinding progresses, the gap The grinding fluid 20 flowing through the pipe is subjected to extremely large resistance. In such a case, the flow rate of the grinding fluid supplied through the shaft center through hole 22 is rapidly reduced because the supply pressure is limited, and as a result, the cooling action and the cleaning are performed. The action can no longer be achieved, and glass chips and fallen abrasive grains in the gap L between the inner and outer grinding side surfaces 26a and 26b of the workpiece W and the inner and outer surfaces of the cylindrical side wall 16b of the core drill 12 ( 24) is clogged (FIG. 6), the drilling speed of the core drill 12 is reduced, the grinding speed drops rapidly, and grinding does not proceed.
[0004]
To solve this problem, grinding is performed to a position slightly deeper than the height of the grindstone 18, and then the grinding is temporarily stopped, the core drill 12 is removed from the workpiece, and the grinding side surfaces inside and outside the workpiece W are removed. 26a, 26b and the grinding method of starting grinding again after removing the glass chips and falling abrasive grains (chips etc.) 24 clogged on the inner and outer peripheral surfaces of the grindstone 18 of the core drill 12 . For this reason, there is a problem that the time required for the grinding process becomes long and the cost increases.
[0005]
Moreover, the conventional core drill apparatus 40 is comprised from the core drill apparatus main body 42 and the core drill 12, as shown in FIG.7 and FIG.8. The core drill apparatus main body 42 has a gantry 44. A work table support base 47 on which the work table 46 is placed and fixed is provided at the center of the upper surface of the gantry 44. A workpiece W such as a glass material such as a quartz glass plate is placed and fixed on the upper surface of the work table 46 via a workpiece pasting plate 45.
[0006]
A support 48 is erected on the periphery of the gantry 44. A long guide 50 is attached to the inner surface side of the support 48 in the vertical direction. A support block 54 is attached to the long guide 50 via a slide bearing 52 so as to be movable up and down.
[0007]
Reference numeral 56 denotes a motor for moving the core drill 12 up and down. The motor 56 is attached to the lower surface side of a plate 58 provided on the side surface of the support 48. A ball screw 60 is rotatably connected to the motor 56. A spindle support 62 is attached to the upper end of the ball screw 60, and one end thereof is connected to the support block 54.
[0008]
A through-hole 64 that opens in the vertical direction is formed in the center of the support block 54, and a rotary shaft 66 is rotatably inserted through the through-hole 64. A pulley 68 is attached to a rotary block 70 attached to the rotary shaft 66 above the support block 54. A core drill 12 is detachably attached to the lower end portion of the rotating shaft 66.
[0009]
Therefore, when the motor 56 rotates, the ball screw 60 rotates, and the spindle support 62 moves up and down along with the rotation, and the support block 54, the rotating shaft 66, and the core drill 12 move up and down at the same time.
[0010]
Reference numeral 72 denotes a motor for rotating the core drill 12 and is attached to the upper portion of the support 48. A motor pulley 76 is attached to the motor shaft 74 of the motor 72. A pulley belt 78 is wound around the motor pulley 76 and the pulley 68.
[0011]
Accordingly, the rotation of the motor 72 is transmitted to the rotating shaft 66 through the motor shaft 74, the motor pulley 76, the pulley 68, and the rotating block 70, and the rotating shaft 66 is rotated. A cover member 80 covers the motor pulley 76, the pulley belt 78, and the pulley 68.
[0012]
The upper end portion of the rotating shaft 66 is connected to the polishing liquid introducing pipe 84 via a rotary 82. As described above, the grinding fluid 20 introduced from the grinding fluid introduction pipe 84 is supplied to the grinding region being ground through the axial through hole 22 (FIG. 6). Reference numeral 86 denotes a manual handle for moving the rotary shaft 66 up and down.
[0013]
If the core drill device in which the core drill 12 is mounted on the core drill device main body 42 having the above-described configuration is used, the core drill 12 is applied to the workpiece W such as quartz glass placed and fixed on the work table 46 via the attaching plate 45. Can be drilled by rotating it while moving it up and down (see, for example, JP-A-7-32205).
[0014]
As described above, such a conventional core drill device 40 has the core drill 12 on the upper side, the workpiece W is positioned below the core drill 12, and the core drill 12 is lowered from the top to the bottom to perform drilling. It was what was going on.
[0015]
In the case of such a core drill device 40, as described above, the chips and the abrasive grains (chips etc.) that have dropped off as the grinding progresses are caused by their own weight inside and outside the workpiece W. The gaps L between the grinding side surfaces 26a and 26b and the inner and outer surfaces of the grindstone 18 of the core drill 12 are easily clogged. Therefore, there is a problem that the time required for the grinding process becomes long and the cost increases.
[0016]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described problems of the prior art, and effectively removes work piece chips and fallen abrasive grains that are clogged between the core drill and the work piece throughout the entire drilling process. It is an object of the present invention to provide a core drill and a core drill apparatus that can be removed, shorten the grinding time, and reduce the cost.
[0017]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a core drill according to the present invention includes a shank acting as a rotating shaft, a disc-shaped bottom wall provided at the upper end of the shank, and a cup-shaped base metal part having an upper opening made of a cylindrical side wall. And a grindstone portion attached to the upper end portion of the base metal portion and having abrasive grains fixed thereto, the grindstone portion being disposed below the workpiece, and the rotating grindstone portion and the workpiece being rotated. A core drill capable of forming a hole by grinding the workpiece into a circular shape by bringing them into contact with each other , comprising a grinding fluid inlet provided penetrating in the shank, and the grinding One or a plurality of grinding fluid flow passages provided in the disk-like bottom wall portion and communicating with the fluid introduction port, and one or more grinding fluid flow passages open to the cylindrical side wall upper end portion A plurality of grinding fluid outlets, One or a plurality of through holes are formed in the disk-shaped bottom wall so as to be ejected from the upper end portion of the cylindrical side wall, and the grinding fluid, the work piece swarf, and the dropped abrasive grains are lowered from the through holes. It is characterized in that it is discharged .
[0018]
By adopting such a structure, chips and falling abrasive grains that increase as grinding progresses downward due to their own weight, so the grinding side surfaces inside and outside the workpiece and the inside and outside surfaces of the core drill are clogged. Therefore, efficient grinding can be performed.
[0019]
In the configuration of the core drill according to the present invention, a grinding fluid introduction port provided through the shank, and one or a plurality of grindings communicated with the grinding fluid introduction port and provided on the disk-shaped bottom wall portion A liquid flow path; and one or a plurality of grinding liquid jets that communicate with the grinding liquid flow path and open at the upper end portion of the cylindrical side wall; and the grinding liquid is ejected from the upper end portion of the cylindrical side wall By configuring so as to efficiently pass the gap between the tip surface and inner and outer peripheral surfaces of the grindstone portion and the surface to be ground of the glass, the grinding region is cooled, and the chips and detachment of the workpiece are removed. Washed abrasive grains are washed out and discharged to the outside together with the grinding liquid, so that efficient grinding can be performed.
[0020]
In the structure of the core drill of the present invention , one or a plurality of through holes are formed in the disk-shaped bottom wall so that the grinding fluid, the work piece swarf, and the dropped abrasive grains are discharged downward from the through holes. By configuring as above, the sustainability of the grinding process can be maintained. Needless to say, the through holes need to be drilled to such an extent that the mechanical strength of the cup-type base metal portion is not impaired.
[0021]
As said abrasive grain, well-known abrasive grains, such as a diamond abrasive grain or a CBN abrasive grain, can be used.
[0022]
A first core drilling apparatus according to the present invention includes: (a) a work table on which a workpiece is attached to a lower surface; and a rotary shaft that is rotatably provided facing the work table. The core drill apparatus main body is provided such that one or both of them can be moved up and down so that they can be moved toward and away from each other, and (b) the core drill having the above-described structure attached to the rotating shaft. In this configuration, it is most preferable to perform the grinding process by lowering the work table located above and bringing the workpiece and the core drill into contact with each other. However, the core drill may be moved upward, or both may be raised. It is also possible to perform grinding by simultaneously performing the lowering and the lowering.
[0023]
The second core drilling apparatus of the present invention comprises: (a) a gantry; a rotary shaft whose tip protrudes upward from the upper surface of the gantry and is rotatably provided; and is opposed to the upper surface of the gantry and is covered. Characterized in that it has a work drill on which a work piece is attached to the lower surface, a core drill apparatus main body comprising guide means for supporting the work table so as to be movable up and down, and (b) the above-described core drill attached to the rotating shaft. To do.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 shows one embodiment of a core drill according to the present invention, wherein (a) is a front view, (b) is a longitudinal sectional view, (c) is a top view, and (d) is a bottom view.
[0025]
FIG. 2 is a cross-sectional explanatory view showing a state in which a hole is formed in a workpiece by the core drill of the present invention and grinding is performed. FIG. 3 is a front view of the core drill apparatus of the present invention. FIG. 4 is a side view of the core drill apparatus of the present invention.
[0026]
1 to 4, the same or similar members as those in FIGS. 5 to 8 may be described using the same reference numerals.
[0027]
As shown in FIG. 1, the core drill 11 of the present invention includes a steel shank 14 that acts as a rotating shaft, a disk-shaped bottom wall 16 a provided at the upper end of the shank 14, and a cylindrical shape. It has a cup-shaped base metal part 16 that is open at the top and includes a side wall 16b, and a grindstone part 17 attached to the upper end of the base metal part 16 to which abrasive grains such as diamond and CBN are fixed. The core drill 11 constitutes a core drill device 41 by being mounted on a core drill device main body 43 described later, and the shank 14, the base metal portion 16, and the grindstone portion 17 are rotated by driving the core drill device 41. By bringing the rotating grindstone portion 17 into contact with the workpiece W, the workpiece W can be ground in a circular shape to make a hole.
[0028]
A grinding fluid inlet 22 is formed at the center of the shank 14. Reference numeral 19 denotes a grinding fluid flow path, which communicates with the grinding fluid introduction port 22 and is provided in the disk-shaped bottom wall 16a portion. In the example shown in the drawing, the grinding fluid flow passage 19 is formed separately as a pipe on the lower surface side of the disc-shaped bottom wall 16a. However, it can also be provided inside the disc-shaped bottom wall 16a. Furthermore, although the number of the grinding fluid flow passages 19 is eight in the illustrated example, it goes without saying that one or a plurality of grinding fluid flow passages 19 can be installed. In terms of grinding efficiency, it is preferable to provide a plurality of grinding fluid flow paths 19 symmetrically to each other.
[0029]
Reference numeral 21 denotes a grinding fluid outlet, which is formed in the cylindrical side wall 16b so as to communicate with the grinding fluid flow passage 19 and open to the upper end portion of the cylindrical side wall 16b. Since the grinding fluid jets 21 are provided in communication with the grinding fluid flow passage 19, one or a plurality of grinding fluid jets 21 are similarly installed, and preferably, the plurality of grinding fluid jets 21 are installed symmetrically to each other. .
[0030]
The grinding fluid 20 introduced into the grinding fluid introduction port 22 is supplied to the grinding region via the grinding fluid flow passage 19 and the grinding fluid ejection port 21.
[0031]
One or a plurality of through holes 23 are formed in the disc-shaped bottom wall 16a. Of the grinding fluid 20 and workpiece W supplied during the grinding process and the dropped abrasive grains (swarf etc.) 24, those falling into the cup-shaped base 16 are moved downward from the through hole 23. To be discharged.
[0032]
Subsequently, a core drill device 41 to which the core drill 11 of the present invention is attached will be described with reference to FIGS.
[0033]
The core drill device 41 of the present invention is different from the conventional core drill device 40 shown in FIGS. 7 and 8 in that the basic components are different from each other in that the arrangement of the core drill and the work table is reversed upside down. There is also a point.
[0034]
The core drill device 41 includes a core drill device main body 43 and a core drill 11. The core drill device 43 has a gantry 44. A support block 90 is installed on the gantry 44. A through hole 92 that opens in the vertical direction is formed in the center of the support block 90, and a rotating shaft 94 is rotatably inserted into the through hole 92.
[0035]
A pulley 96 is attached to a rotary block 98 attached to the rotary shaft 94 below the support block 90. A core drill 11 is detachably attached to the upper end portion of the rotary shaft 94.
[0036]
Reference numeral 100 denotes a motor for rotating the core drill 11 and is built in the gantry 44. A motor pulley 102 is attached to the motor shaft of the motor 100. A pulley belt 104 is wound around the motor pulley 102 and the pulley 96.
[0037]
Therefore, the rotation of the motor 100 is transmitted to the rotating shaft 94 via the motor pulley 102, the pulley belt 104, the pulley 96, and the rotating block 98, and the rotating shaft 66 is rotated.
[0038]
The lower end portion of the rotating shaft 94 is connected to a grinding fluid introduction pipe 108 through a rotary joint 106. As described above, the grinding fluid 20 introduced from the grinding fluid introduction pipe 108 is jetted and supplied to the grinding region via the grinding fluid introduction port 22, the grinding fluid flow passage 19, and the grinding fluid ejection port 21 (FIG. 2). ).
[0039]
Reference numerals 110 and 110 denote side plates installed opposite to the upper surface of the gantry 44. An upper plate 112 is provided on the upper ends of the side plates 110 and 110. A motor 114 moves the workpiece W up and down, and is installed on the upper surface of the upper plate 112. A ball screw 116 is rotatably connected to the motor 114.
[0040]
Reference numerals 118 and 118 denote guide rods which are erected on the frame 44 so as to face each other. A work table 122 is attached to the guide rods 118 and 118 through slide bearings 120 and 120 so as to be movable up and down. The work table 122 is attached to the ball screw 116 and moves up and down by the rotation of the ball screw 116.
[0041]
The workpiece W is attached and fixed to the lower surface of the work table 122 via a sticking plate 124 so that the workpiece W does not fall downward.
[0042]
If the core drill device 41 in which the core drill 11 is mounted on the core drill device main body 43 having the above-described configuration is used, the core drill 11 is applied to the workpiece W such as quartz glass fixed to the lower surface of the work table 122 via the affixing plate 124. The hole making process can be performed by abutting from below while rotating.
[0043]
According to the present invention, the grinding fluid 20 supplied from the grinding fluid inlet 22 is ejected from the grinding fluid outlet 21 during the grinding process, and the tip and inner and outer peripheral surfaces of the grinding wheel portion 17 and the workpiece W are covered. While passing through the gap L with the grinding surface, the grinding area is cooled, and the swarf of the workpiece W and the dropped abrasive grains (swarf etc.) 24 are washed away.
[0044]
At this time, in the conventional configuration, the gap L between the grinding side surfaces 26a and 26b of the workpiece W and the inner and outer surfaces of the cylindrical side wall 16b of the core drill 12 opens upward (FIG. 6). Therefore, the grinding fluid 20 and the chips 24 are discharged to the outside in a state of overflowing upward from the opening of the gap L, and the grinding depth 24 increases and the chips 24 are clogged in the gap L. I stopped grinding.
[0045]
However, according to the present invention, the gap L1 between the grinding side surfaces 26a, 26b of the workpiece W and the inner and outer surfaces of the cylindrical side wall 16b of the core drill 11 is open downward (FIG. 2). In addition, since the grinding fluid 20 and the chips 24 fall directly from the opening of the gap L1, the gap L1 is not clogged, the drilling speed of the core drill 11 is not reduced, and the conventional Since there is no need to remove the chips 24 clogged in the gap as in the case, the time required for the grinding process is shortened and the cost is also reduced. Furthermore, the grinding fluid 20 and the chips 24 that have dropped down reach the upper surface of the disk-shaped bottom wall 16a, but these grinding fluid 20 and the chips 24 are discharged from the through hole 23 to the outside of the base metal part 16. , It will not accumulate inside the base metal part 16.
[0046]
【Example】
Examples of drilling a workpiece using the core drill device of the present invention will be described below. Needless to say, this example is given by way of illustration and should not be construed as limiting.
[0047]
Example 1
Cup type base metal dimensions are 98mm outer diameter, 92mm inner diameter, and 125mm height. Taper is applied to the inside of the shank mounting disk of the cup type base metal, and the outside of the shank mounting part of the same disk. Four shavings outlets were drilled through, and a shank having a diameter of 30 mm and a grinding fluid inlet opening serving as a 10 mm rotating shaft was attached. After that, four diamond grinding stone chips with a diamond particle size of # 120, thickness 5mm, width 15mm and height 10mm were sintered with metal bonds at equal intervals, and then a 1mm diameter grinding liquid was sprayed onto the cylindrical wall of the base metal part. Eight nozzles were provided. Processing was performed so that the position of the grinding liquid ejection nozzle was located on both sides of the diamond grindstone chip. Further, eight holes with a diameter of 1 mm were made in the shank portion, and a grinding fluid introduction pipe having an outer diameter of 3 mm and an inner diameter of 1 mm was welded to produce a core drill.
[0048]
The above core drill is mounted on the core drill device so that the diamond grinding wheel tip is located above the shank part, and a quartz glass disk having a diameter of 200 mm and a thickness of 100 mm is attached to the work fixing table, and the outer diameter is 10 mm thicker than that. The glass sheet was heat-welded with wax to the glass sheet, and the glass sheet was mounted so that the glass sheet was above the quartz glass disk, and a hole having a diameter of 100 mm was drilled in the center. During the drilling process, water as the grinding fluid was continuously supplied from the grinding fluid inlet of the chunk at a pressure of 2 kg / cm ² .
[0049]
Drilling was performed with the workpiece fixing table descent speed set to 5 mm per minute, but during the machining, chips flowed out from the inner and outer peripheral surfaces of the core drill without clogging the gap between the core drill and quartz glass. The processing was finished. The time required for processing was 25 minutes.
[0050]
(Comparative Example 1)
A conventional core drill (with no grinding fluid jet nozzle) is the same size as the core drill used in the example, and is mounted on the core drill device in which the conventional core drill descends, and the same size quartz glass as in the example Was used to drill holes under the same conditions.
[0051]
The core drill progressed smoothly at the beginning of drilling, but when the drilling depth reached 20mm, chips clogged in the gap between the core drill and quartz glass, the cutting speed decreased, and the drilling depth decreased. When it reached 25 mm, the core drill stopped rotating due to clogging of chips. The core drill device was turned off, the core drill was pulled out of the quartz glass, and after removing the chips, drilling was started again. However, when the depth of the new cutting portion reached about 25 mm, the core drill stopped again. Again, the core drilling device was turned off, the core drill was pulled out of the quartz glass, and after cutting chips were removed, drilling was started. After repeating the same operation two more times, the drilling process was finally completed.
[0052]
The time required for drilling was about 100 minutes, which was about four times as long as that of the example. When the processed quartz glass was removed from the soda glass and observed, large cracks and chipping were found in the core drilling portion, leading to a significant deterioration in quality.
[0053]
【The invention's effect】
As described above, according to the present invention, it is possible to effectively remove workpiece chips and falling abrasive grains clogged between the core drill and the workpiece over the entire drilling grinding process. Time can be shortened and cost can be reduced.
[Brief description of the drawings]
FIG. 1 shows one embodiment of a core drill according to the present invention, wherein (a) is a front view, (b) is a longitudinal sectional view, (c) is a top view, and (d) is a bottom view. .
FIG. 2 is a cross-sectional explanatory view showing a state in which a hole is made in a workpiece by the core drill of the present invention and grinding is performed.
FIG. 3 is a front view of the core drill apparatus of the present invention.
FIG. 4 is a side view of the core drill apparatus of the present invention.
5A and 5B show an example of a conventional core drill, in which FIG. 5A is a front view, FIG. 5B is a longitudinal sectional view, and FIG. 5C is a bottom view.
FIG. 6 is an explanatory cross-sectional view showing a state in which a drilling process is performed on a workpiece by a conventional core drill.
FIG. 7 is a front view showing an example of a conventional core drill device.
FIG. 8 is a side view of FIG. 7;
[Explanation of symbols]
11: Core drill of the present invention, 12: Conventional core drill, 14: Steel shank, 16: Cup-shaped base metal part, 16a: Disk-shaped upper wall, disk-shaped bottom wall, 16b: Cylindrical side wall, 17 : Grinding wheel part, 18: Grinding wheel part, 19: Grinding fluid flow path, 20: Grinding fluid, 21: Grinding fluid outlet, 22: Axial through hole, grinding fluid inlet, 23: Through hole, 24: Chip and Dropped abrasive grains (swarf etc.), 26a, 26b: grinding side, 40: conventional core drill device, 41: core drill device of the present invention, 42: conventional core drill device main body, 43: core drill device main body of the present invention, 44 : Stand, 45, 124: Pasting plate, 46, 122: Work table, 47: Work table support base, 48: Support, 50: Long guide, 52, 120, 120: Slide bearing, 54: Support block, 5 6: motor, 58: plate, 60, 116: ball screw, 62: spindle support, 64: through hole, 66, 94: rotating shaft, 68, 96: pulley, 70, 98: rotating block, 72, 100, 114: Motor, 74: Motor shaft, 76, 102: Motor pulley, 78, 104: Pulley belt, 80: Cover member, 82, 106: Rotary joint, 84, 108: Grinding fluid introduction pipe, 86: Manual handle, 90: Support Block, 92: Through hole, 110, 110: Side plate, 112: Upper plate, 118, 118: Guide rod, L, L1: Gap, W: Workpiece.

Claims (4)

A shank that acts as a rotation shaft, a disc-shaped bottom wall provided at the upper end of the shank, and a cup-shaped base metal part that is open at the top, and a top part of the base metal part that is attached to the top part of the base metal part and is ground A grindstone portion to which the grains are fixed, the grindstone portion is disposed below the workpiece, and the rotating grindstone portion and the workpiece are brought into contact with each other, thereby making the workpiece circular. A core drill that can be drilled to form a hole , and is connected to the grinding liquid introduction port provided through the shank, to the grinding liquid introduction port, and to the disk-shaped bottom wall portion. And further comprising one or a plurality of grinding fluid flow passages provided, and one or a plurality of grinding fluid jets communicating with the grinding fluid flow passages and opening at an upper end portion of the cylindrical side wall, Liquid is ejected from the upper end of the cylindrical side wall and One or a plurality of through-holes in a disk-shaped bottom wall bored, grinding fluid, core drill, characterized in that it has to discharge downward the abrasive grains chips and detachment of the workpiece from the through hole.   The core drill according to claim 1, wherein the abrasive grains are diamond abrasive grains or CBN abrasive grains.   (A) A work table on which a work piece is attached to the lower surface and a rotary shaft that is rotatably provided facing the work table, so that the work table and the rotary shaft can be brought into contact with and separated from each other. A core drill apparatus comprising: a core drill apparatus main body having one or both of which can be moved up and down; and (b) the core drill according to claim 1 attached to the rotating shaft.   (A) a gantry, a rotary shaft whose tip protrudes upward from the upper surface of the gantry and is rotatably provided, and a work table provided facing the upper surface of the gantry and on which a workpiece is attached to the lower surface; A core drill apparatus comprising: a core drill apparatus main body comprising guide means for supporting the work table so as to move up and down; and (b) the core drill according to claim 1 attached to the rotating shaft.

Images