JPWO2012029666A1 - Glass drill bits - Google Patents

Abstract

The present invention is a glass drill for performing drilling by contacting glass while rotating, formed on the glass, with a tip contacting the glass and having a curved surface at an outer peripheral edge. An outer peripheral portion inserted into the hole; a shank; and a relief portion having a smaller diameter than the outer diameter of the outer peripheral portion between the outer peripheral portion and the shank. A glass drill having a groove extending in the axial direction and extending in the axial direction, and an edge of the groove opening at the tip is chamfered.

Description

  The present invention relates to a glass drill, and more particularly to a glass drill for drilling a sheet glass.

  For example, a plasma display panel (PDP) has a front glass substrate on which electrodes are formed, and a back surface in which red, green, and blue phosphor layers and electrodes are formed in grooves partitioned by ribs. The glass substrate and the glass substrate are opposed and integrally joined. And between the two glass substrates, a sealed minute gap with a peripheral edge sealed is formed. Further, the inside of the minute gap is sealed in a state filled with a gas containing argon and neon for generating discharge.

  In the rear glass substrate, a through hole communicating with the minute gap is provided outside the display area. This through hole is used as an exhaust hole for exhausting the air in the minute gap after joining the two glass substrates in the manufacturing process, and then a gas supply hole for filling the gas in the minute gap. Used as.

  In the through hole processing step, a drilling drill having fine diamond abrasive grains on its surface is rotated at a high speed to drill the glass substrate (for example, see Patent Document 1). The drilling of the glass substrate is performed by the first drill from above and the second drill from below at the same time, pulling out the first drill first, feeding the second drill further in the axial direction, and processing from above The first hole thus made communicates with the second hole machined from below. Thereby, when the drill tip penetrates the glass substrate, chipping (hammer chipping) is prevented from occurring at the opening peripheral edge of the through hole.

  Here, the configuration of a conventional drill will be described. As shown in FIG. 1, the conventional drill 60 is formed in a cylindrical shape, and a chamfer 62 is provided at the tip corner.

  When drilling the glass substrate G using the drill 60, the corner 64 between the tip surface and the chamfer 62 comes into contact with the surface of the glass substrate G, and a crack H (shown by a broken line in FIG. 1) occurs. Hama chip H occurs toward the outside of the corner 64. Therefore, since the chipping H is advanced outside the outer periphery of the drill 60, after the drilling process, the missing part due to the hooking H remains without being removed. Further, when the drilling hole reaches the penetration position and is pulled out (up-and-down direction changing operation), cracking occurs due to mechanical fine vibration. These cracks cause hole cracking in the back plate baking process.

International Publication 2008 / 044771A1

  Thus, when grinding a through hole in a glass substrate using a drill as described in the above-mentioned Patent Document 1, the above-mentioned chipping occurs when the tip of the drill that rotates at high speed comes into contact with the glass surface. Chipping from the peripheral edge of the through hole to the outside tends to occur, and there is a problem that the chipped portion remains on the inner wall of the through hole even after drilling.

  Further, in the drilling process using the above drill, the drill is sent in the thickness direction of the glass substrate, and when the drilling process is performed to a predetermined depth, the feed of the drill is stopped and the drill is pulled out from the hole. Drilling is performed according to the procedure. Further, when the drill reaches the penetration position and is pulled out, if the outer peripheral portion of the drill comes into contact with the inner wall of the through hole, chipping occurs at the peripheral edge of the inlet of the through hole.

  Further, in a plasma display panel manufacturing factory, after bonding two glass substrates, a baking step is performed in which the glass substrate is heated to a high temperature (for example, 590 ° C. to 600 ° C.) in a dielectric layer forming step. In the glass substrate firing process, if there are cracks due to drilling by drilling or scratches due to chipping, thermal stress (compressive stress, tensile stress) acts on the glass substrate due to changes in temperature distribution accompanying heating and cooling. There arises a problem that hole cracks originating from cracks and scratches at the time of drilling occur in the glass substrate.

  Therefore, in view of the above circumstances, the present invention suppresses the occurrence of chipping and chipping that occur when the drilling drill is brought into contact with the glass substrate and when the drilling drill reaches the penetration position and is pulled out. An object of the present invention is to provide a glass drilling hole in which the above problems are solved.

In order to solve the above problems, the present invention has the following means.
(1) The present invention is a glass drill for making a hole in contact with glass while rotating,
A tip portion in contact with the glass and having a curved surface on the outer peripheral side edge;
An outer periphery inserted into a hole formed in the glass;
Shank,
Between the outer peripheral portion and the shank, there is a relief portion that is smaller than the outer diameter of the outer peripheral portion,
The distal end portion has a groove extending from the central portion in the outer peripheral direction and extending in the axial direction;
The edge of the groove opening at the tip is chamfered.
(2) It is preferable that the said relief part of this invention is a taper shape or a curved surface shape.
(3) The glass of the present invention is preferably a plate glass for plasma display.
(4) The hole of the present invention preferably has an inner diameter of 1.0 mm to 2.0 mm, and the glass preferably has a thickness of 0.5 mm to 1.8 mm.

  According to the present invention, since the outer peripheral side edge of the tip that contacts the glass surface is formed in a curved shape, the area of occurrence of chipping when the drilling drill contacts the glass surface is determined from the outer diameter of the drill. It is possible to fit within the inner range, and the chipping can be removed in the process in which the drill tip is fed in the glass thickness direction. Further, since the groove is formed in the radial direction from the center portion of the tip portion toward the outer peripheral side, the center portion of the tip portion is not affected by the heat due to grinding. Furthermore, since the coolant liquid (cooling liquid) at the time of grinding and the chips from the grinding are discharged through the groove, the heat accompanying grinding can be efficiently taken away, and the cooling effect can be enhanced. In addition, by forming an escape portion that is smaller in diameter than the outer diameter of the outer peripheral portion between the outer peripheral portion inserted into the glass hole and the shank, This makes it difficult for chipping and chipping to occur at the peripheral edge of the inlet of the steel sheet, thereby improving the quality of the drilling process.

FIG. 1 is a front view showing a conventional glass drill. FIG. 2 is a front view showing an embodiment of the glass drilling drill according to the present invention. FIG. 3A is a longitudinal sectional view showing a drilling procedure 1 of the first processing method using the glass drilling drill according to the present invention. FIG. 3B is a longitudinal sectional view showing a drilling procedure 2 of the first processing method using the glass drilling drill according to the present invention. FIG. 3C is a longitudinal sectional view showing a drilling procedure 3 of the first processing method using the glass drilling drill according to the present invention. FIG. 3D is a longitudinal sectional view showing a drilling procedure 4 of the first processing method using the glass drilling drill according to the present invention. FIG. 3E is a longitudinal sectional view showing a drilling procedure 5 of the first processing method using the glass drilling drill according to the present invention. FIG. 3F is a longitudinal sectional view showing a drilling procedure 6 of the first processing method using the glass drilling drill according to the present invention. FIG. 4A is a longitudinal sectional view showing a drilling procedure 1 of the second processing method using the glass drilling drill according to the present invention. FIG. 4B is a longitudinal sectional view showing a drilling procedure 2 of the second processing method using the glass drilling drill according to the present invention. FIG. 5A is a plan view showing a groove of a glass drilling drill according to the present invention. FIG. 5B is a front view showing the grooves of the glass drilling drill according to the present invention. FIG. 6 is a front view showing a modified example of the glass hole drill according to the present invention.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
[Embodiment 1]

  FIG. 2 is a front view showing an embodiment of the glass drilling drill according to the present invention. As shown in FIG. 2, a glass hole drill (hereinafter referred to as “drill”) 10 includes a grinding portion 20 (shown in a satin pattern in FIG. 1) and a shank 30. The cylindrical grinding part 20 has minute diamond abrasive particles fixed on the surface of a metal material, and is provided so as to form a substantially uniform grinding surface over the entire circumference. For example, diamond abrasive grains having a particle size of 200 mesh or more are preferably fixed to the grinding unit 20 by a metal bond method or an electrodeposition method.

  Furthermore, the outer peripheral side edge portion of the tip portion 21 of the grinding portion 20 is formed by an arcuate curved surface 22. The curved surface 22 of the distal end portion 21 suppresses cracking at the time of contact with the glass surface, and makes it possible to set the area where the cracking occurs at a center near the outer periphery of the distal end portion 21.

  For example, the curved surface 22 preferably has a radius of curvature R1 smaller than a radius R2 of the outer peripheral portion 24 (R1 <R2). Further, when the radius R2 of the outer peripheral portion 24 is 0.5 mm, for example, the curvature radius R1 is 0.1 mm or more and less than 0.5 mm. When the radius R2 of the outer peripheral portion 24 is 1.0 mm, for example, the curvature radius R1 is 0.1 mm or more and less than 1.0 mm. The central angle of the arc shape of the curved surface 22 is preferably 45 ° or more and 90 ° or less.

  Moreover, although the center part except the curved surface 22 is planar shape, the front-end | tip part 21 is good also as a curved surface which consists of a gentle circular arc. The plane of the tip 21 is determined according to the radius of curvature R1 of the curved surface 22, and the plane area decreases as the radius of curvature R1 approaches the radius R2 of the outer periphery 24.

  As shown in FIGS. 5A and 5B, the drill 10 of the present invention has a U-shaped groove 110 extending from the central portion of the tip end portion 21 in the outer circumferential direction, and the groove is further axially extended. The edge of the groove 110 that extends and opens at the tip 21 is chamfered (chamfer 120).

  In the drill 10, when the tip portion 21 is viewed from the axial direction, the groove 110 is formed in the radial direction from the center portion toward the outer peripheral side, so that the grinding portion 20 is formed in a shape similar to a U shape or a horseshoe shape. ing. Further, in the drill 10, the central portion of the tip portion 21 (the portion where the rotation speed becomes low) is not affected by the heat of grinding due to the groove 110. Furthermore, since the coolant liquid (cooling liquid) at the time of grinding and the chips by grinding are discharged through the groove 110, the heat accompanying grinding can be efficiently taken away, and the cooling effect can be enhanced.

  Further, the chamfer 120 of the groove 110 opened at the tip 21 can prevent the diamond abrasive grains from being peeled off during grinding.

  Therefore, in the drill 10 of the present invention, the drill life can be greatly extended as compared with the conventional one by the interaction between the groove 110 and the chamfer 120.

The glass drilling drill according to the present invention is preferably used for drilling a glass substrate having a thickness of 0.5 mm to 1.8 mm, and used for drilling a glass substrate having a thickness of 1.0 mm to 1.8 mm. It is more preferable.
The axial length L1 (including the curved surface 22) of the outer peripheral portion 24 is determined according to the thickness of the glass substrate to be processed. For example, when the thickness of the glass substrate is 0.5 mm to 1.0 mm, the axial length L1 of the outer peripheral portion 24 is preferably 0.3 mm to 0.8 mm. When the thickness of the glass substrate is 1.0 mm to 1.8 mm, the length L1 of the outer peripheral portion 24 is preferably 0.8 mm to 1.6 mm.

  Further, the axial length L2 (excluding the curved surface 22) of the outer peripheral portion 24 is preferably 0.1 mm to 0.6 mm when the thickness of the glass substrate is 0.5 mm to 1.0 mm. When the thickness of the glass substrate is 1.0 mm to 1.8 mm, it is preferably 0.6 mm to 1.4 mm.

  Between the outer peripheral portion 24 and the shank 30, a relief portion 26 having a smaller diameter than the outer peripheral portion 24 is formed. The escape portion 26 is formed in a tapered shape that is inclined inward with respect to the outer peripheral portion 24 at an inclination angle α. The axial length of the escape portion 26 is preferably 0.1 mm or more, and the inclination angle α is preferably in the range of 2 ° to 60 °, for example.

  Further, an arcuate portion 50 having a gently curved surface is formed at the boundary portion between the outer peripheral portion 24 and the escape portion 26. The relief portion 26 and the arcuate portion 50 prevent the drill 10 from reaching the penetrating position and damaging the entrance peripheral edge of the hole when the drill 10 is pulled out, thereby preventing chipping during the drill pulling operation.

[Drilling procedure by the first machining method using the glass drilling drill of the present invention]
3A to 3F are longitudinal sectional views showing drilling procedures 1 to 6 of the first processing method using the glass drilling drill according to the present invention. 3A to 3F, the configurations of the drive unit and the feed mechanism that rotationally drive the drill are well known (refer to the above-mentioned Patent Document 1), and thus the description thereof is omitted here. 3A to 3F, the grooves are omitted for simplicity.

(Drilling procedure 1 of the first processing method)
As shown in FIG. 3A, when drilling with the drill 10 in the glass substrate G, the first drill 10 </ b> A disposed on the first main surface side of the glass substrate G and the second main surface side are disposed. The second drill 10B comes into contact with the first main surface and the second main surface of the glass substrate G almost simultaneously. The first and second drills 10 </ b> A and 10 </ b> B have the same configuration as the drill 10 shown in FIG. 2, and the chucking direction is set in the opposite direction to the thickness direction of the glass substrate G. The glass substrate G is used for the back glass substrate of the plasma display panel described above.

  Further, since the first and second drills 10A and 10B are rotating at high speed (thousands of times per minute), they come into contact with the surface of the glass substrate G and start drilling for drilling. In the grinding step, a coolant liquid (cooling liquid) is supplied to the contact portion between the first and second drills 10A and 10B and the glass substrate G. Since the first and second drills 10A and 10B each have a groove formed in the radial direction from the central portion toward the outer peripheral side, the central portion (portion where the rotational speed is low) of the distal end portion. It is not affected by grinding heat. Furthermore, since the coolant liquid (cooling liquid) and the chips from the grinding are discharged through the groove 110, the heat associated with the grinding can be efficiently removed, and the cooling effect can be enhanced.

  In the surface portion of the glass substrate G where the tips of the first and second drills 10A and 10B first contact, a crack H (shown by a broken line in FIG. 3A) occurs. Since the area where the chipping H is generated is determined by the boundary between the tip 21 and the curved surface 22 of the first and second drills 10A and 10B, it is inside the curved surface 22 by the curvature radius R1.

(Drilling procedure 2 of the first processing method)
As shown in FIG. 3B, the first and second drills 10A and 10B are fed in the thickness direction of the glass substrate G while rotating at high speed. Accordingly, the first and second holes 70A and 70B by the drills 10A and 10B are ground on the first main surface and the second main surface of the glass substrate G.

  The first and second drills 10A and 10B grind the glass substrate G, and the bottoms of the holes 70A and 70B (shown in FIG. 3B) gradually become deeper. Thereby, the hammer chip H generated on the surface (first main surface, second main surface) of the glass substrate G is a curved surface formed at the outer peripheral side edge of the tip 21 of the first and second drills 10A, 10B. 22 is ground and removed.

(Drilling procedure 3 of the first processing method)
As shown in FIG. 3C, the first drill 10 </ b> A is pulled out to the first main surface side when a hole 70 </ b> A having a predetermined depth is ground on the first main surface of the glass substrate G. The bottom of the first hole 70A is close to the upper surface of the glass substrate G, and the depth is relatively shallow.

  Further, the second drill 10B is fed in the thickness direction of the glass substrate G while rotating at high speed as it is, and deeply grinds the hole 70B on the second main surface side of the glass substrate G.

(Drilling procedure 4 of the first processing method)
As shown in FIG. 3D, when the second drill 10B reaches the penetration position, the feeding of the second drill 10B in the thickness direction of the glass substrate G is stopped. As a result, the first and second holes 70A and 70B are in communication with each other and become a through hole 70 that penetrates the glass substrate G in the thickness direction. In the present embodiment, the through hole 70 has an inner diameter of, for example, 1.0 mm to 2.0 mm. Further, a step due to the radial displacement of the first and second drills 10A and 10B remains on the inner wall of the through hole 70 at the boundary portion between the first hole 70A and the second hole 70B. However, since this level difference occurs at a position close to the first main surface side of the glass substrate G, the thermal stress in the baking process described above acts as a compressive stress, and does not cause damage to the glass that is resistant to compression. .

  In addition, after the through hole 70 is ground, the second drill 10B is pulled out to the second main surface side. In addition, the inner peripheral surface of the through hole 70 is ground by the outer peripheral portion 24 of the second drill 10 </ b> B, and has a hole diameter slightly larger than the diameter D of the outer peripheral portion 24.

  Moreover, since the escape part 26 is provided between the outer peripheral part 24 and the shank 30 of the grinding part 20 of the 2nd drill 10B, when the 2nd drill 10B reaches | attains a penetration position and pulls out, a relief part 26 does not contact the inlet peripheral portion (second main surface side opening) of the through hole 70, and the occurrence of chipping is suppressed.

(Drilling procedure 5 of the first processing method)
As shown in FIG. 3E, the outer peripheral portion 24 is the inner peripheral surface of the through hole 70 after the escape portion 26 moves to the outside of the through hole 70 in the process in which the second drill 10B is pulled out to the second main surface side. To move.

(Drilling procedure 6 of the first processing method)
As shown in FIG. 3F, when the tip 21 of the second drill 10B passes through the inlet peripheral edge (second main surface side opening) of the through hole 70, the curved surface 22 is formed on the outer peripheral edge. As a result, it moves to the outside of the through hole 70 without contacting the peripheral edge of the inlet of the through hole 70. Therefore, when the second drill 10B is pulled out from the through hole 70, chipping can be prevented from occurring at the entrance peripheral edge of the through hole 70.

[Drilling procedure by the second machining method using the glass drilling drill of the present invention]
Here, a description will be given of a drilling procedure by a second processing method different from the first processing method. 4A to 4B are longitudinal sectional views showing drilling procedures 1 and 2 of the second processing method using the glass drilling drill according to the present invention. 4A to 4B, the grooves are omitted for simplicity.

(Drilling procedure 1 of the second machining method)
In the drilling procedure 1 of the second processing method shown in FIG. 4A, only the second drill 10B is sent in the thickness direction of the glass substrate G while rotating at high speed. Thereby, the second hole 70B by the drill 10B is ground on the second main surface of the glass substrate G. Since the second drill 10B has a groove formed in the radial direction from the center portion toward the outer peripheral side, the center portion (portion where the rotation speed is low) of the tip portion is not affected by heat due to grinding. It will end. Furthermore, since the coolant liquid (cooling liquid) and the chips from the grinding are discharged through the groove 110, the heat associated with the grinding can be efficiently removed, and the cooling effect can be enhanced.

  The second drill 10B is fed in the thickness direction of the glass substrate G while grinding the glass substrate G, and the second hole 70B is gradually deepened. Thereby, the hammer chip H generated on the second main surface of the glass substrate G when the tip 21 of the second drill 10B comes into contact is a curved surface formed on the outer peripheral side edge of the tip 21 of the second drill 10B. As 22 passes, it is ground and removed.

  The second drill 10B is fed in the thickness direction of the glass substrate G until the tip 21 reaches a position close to the first main surface of the glass substrate G, and the bottom of the second hole 70B and the first of the glass substrate G are sent. Grinding is performed until the thickness of the main surface is, for example, about 0.1 mm to 0.5 mm (depending on the design dimensions of the drill, it is desirable that the relief portion 26 enters 0.2 mm or more in the glass thickness direction. ). Therefore, the 1st main surface side of the 2nd hole 70B processed into glass substrate G will be in the state where it was plugged up by the very thin wall.

  Thereafter, the grinding by the second drill 10B is stopped, the second drill 10B is moved, and is pulled out to the second main surface side of the second hole 70B. As with the case shown in FIGS. 3E and 3F described above, the pulling operation of the drill toward the second main surface side causes chipping at the inlet peripheral edge of the through hole 70 when the second drill 10B is pulled out from the through hole 70. Can be prevented.

(Drilling procedure 2 of the second machining method)
In the drilling procedure 2 of the second processing method shown in FIG. 4B, only the first drill 10A is fed in the thickness direction of the glass substrate G while rotating at high speed. Thereby, the first hole 70A by the first drill 10A is ground on the first main surface of the glass substrate G. In this case, since only a very thin wall remains on the first main surface side of the second hole 70B, the tip 21 of the first drill 10A rotates at a high speed and comes into contact with the first main surface of the glass substrate G. While grinding, it becomes the through-hole 70 which the 1st, 2nd hole 70A, 70B connected. Then, the grinding powder ground by the first drill 10A passes through the through hole 70 and falls to the second main surface side.

  In addition, when the first drill 10A grinds the first main surface of the glass substrate G, the chipping H occurs as described above, but the first drill 10A is sent in the thickness direction of the glass substrate G and the tip When the curved surface 22 formed at the outer peripheral side edge of the portion 21 passes, the chipping H is ground and removed. Further, since the first drill 10A has a groove formed in the radial direction from the central portion toward the outer peripheral side, the central portion (portion where the rotational speed is low) of the tip portion is affected by the heat of grinding. You do n’t have to.

  Moreover, when the curved surface 22 formed in the outer peripheral side edge part of the front-end | tip part 21 of 1st drill 10A is inserted in the 1st main surface of the glass substrate G, grinding by 1st drill 10A will be stopped, and 1st drill 10A will be stopped. And move to the first main surface side. When the first drill 10A is moved in the thickness direction of the glass substrate G and is ground and then pulled out to the first main surface side, the amount of grinding from the first main surface side is extremely small. In addition, chipping and chipping are less likely to occur at the peripheral edge of the inlet, and the processing time can be shortened.

  Next, a modified example of the drill will be described.

[Modification]
FIG. 6 is a front view showing a modification of the glass hole drill. In addition, in a modification, the same part as the said Embodiment 1 attaches | subjects the same code | symbol, and abbreviate | omits the description.

  As shown in FIG. 6, the drill 100 according to the modified example includes the groove 110 and the chamfer 120, and a clearance 210 having a smaller diameter than the outer periphery 24 is formed between the outer periphery 24 and the shank 30. ing. The escape portion 210 is formed in a curved surface having a gentle arc shape. In addition, by increasing the curvature radius of the escape portion 210, the curved surface of the escape portion 210 approaches a tapered shape.

  When the through hole 70 is machined using the drill 100 according to this modification, in the above drilling procedure 4, when the second drill 10B is pulled out, the curved relief portion 210 becomes the inlet peripheral edge (second The main surface side opening) is not contacted and the occurrence of chipping is suppressed.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application No. 2010-196216 filed on Sep. 1, 2010, the contents of which are incorporated herein by reference.

  In the above description, the case of drilling a glass substrate G used for a plasma display panel has been described as an example. However, the present invention is not limited thereto, and a hole for drilling a glass substrate used for other display devices is described. Of course, the present invention can also be applied to a drill.

  Further, in the above description, the configuration in which the abrasive grains such as diamond abrasive grains are fixed to the surface of the escape portion has been described. However, the present invention is not limited thereto, and the abrasive grains such as diamond abrasive grains are not fixed to the surface of the escape portion. Of course, the present invention can also be applied to a drill.

  In the above description, the diamond abrasive grains are fixed to the surface of the grinding part. However, the present invention is not limited to this, and the present invention can also be applied to a drill for fixing abrasive grains other than diamond abrasive grains. Of course you can.

  Moreover, in the said description, grinding is started simultaneously from the thickness direction of a glass substrate, the 1st drill from a 1st main surface is stopped first, and the processing method which penetrates the 2nd drill from a 2nd main surface is an example. However, the present invention is not limited to this, and in the case of machining with other machining procedures (for example, drilling with the first drill from the first main surface is performed first, and then the second drill from the second main surface. Of course, the present invention can also be applied to a processing method for performing a drilling process by the above method.

DESCRIPTION OF SYMBOLS 10, 100 Glass drill 10A 1st drill 10B 2nd drill 20 Grinding part 21 Tip part 22 Curved surface 24 Peripheral part 26, 210 Relief part 30 Shank 50 Arc-like part 70A, 70B Hole 70 Through-hole 110 Groove 120 Chamfering G Glass Substrate H

Claims (4)

It is a glass drilling drill that drills in contact with the glass while rotating,
A tip portion in contact with the glass and having a curved surface on the outer peripheral side edge;
An outer periphery inserted into a hole formed in the glass;
Shank,
Between the outer peripheral portion and the shank, there is a relief portion that is smaller than the outer diameter of the outer peripheral portion,
The distal end portion has a groove extending from the central portion in the outer peripheral direction and extending in the axial direction;
A glass drill with a chamfered edge of the groove opening at the tip.   2. The glass drilling hole according to claim 1, wherein the relief portion has a tapered shape or a curved shape.   The glass drilling hole according to claim 1 or 2, wherein the glass is a plate glass for a plasma display.   The said hole has an internal diameter of 1.0 mm-2.0 mm, The said glass has a thickness of 0.5 mm-1.8 mm, The glass punching as described in any one of Claims 1 thru | or 3. drill.

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