JPH04300150A - Honing process method of drill - Google Patents

Abstract

PURPOSE:To apply a flat honing process to the cutting edge of a drill. CONSTITUTION:A side face grinding portion 15b is formed by planting a hard brush 15 on the periphery of a grinding wheel 9. The grinding wheel 9 is inclined by (180-phi)/2 to a drill tip angle phi to face the side face grinding portion 15b to a cutting edge 18. Furthermore, the grinding wheel 9 is inclined by a certain honing angle to the cutting edge 18. After that, the grinding wheel 9 is revolved around an axis, and a drill 6 is fed to in the axis direction to press the cutting edge 18 against the side face grinding portion 15b.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a honing method suitable for honing the cutting edge of a drill.

0002

[Prior Art] Conventionally, in cutting tools having cutting edges made of cemented carbide, the cutting edge is often subjected to minute honing to prevent chipping, and the shape and size of this honing are determined by the performance of the tool. is known to have a significant impact on For example, Japanese Utility Model Publication No. 63-34802 discloses an example of honing a relatively simple indexable tip using an elastic grindstone. By the way, among such honing processes, honing of indexable inserts can be done relatively easily due to the simple shape of the cutting edge, but in the case of drills used for hole drilling, the cutting edge has a tip angle. This is often difficult due to the complicated shape of the cutting edge. In particular, it is extremely difficult to perform uniform honing from the outer periphery to the center of the cutting edge by mechanical means.For this reason, conventionally honing was performed manually using a diamond file with a diamond grindstone attached. It was common to do so. In this regard, as seen in Japanese Patent Publication No. 1-34727, it has been proposed to mechanically perform honing by pressing the cutting edge of the drill tip against the circumferential surface of an elastically deformable grindstone such as a brush or buffing stone. has been done.

0003

[Problems to be Solved by the Invention] However, since the honing process using the above-mentioned mechanical means is originally aimed at honing a convex arc surface, it is difficult to perform a flat honing process, and it is difficult to adjust the honing angle. It's also difficult. In addition, since the grinding wheel is moved from the rake face of the drill toward the flank face of the drill tip or in the opposite direction, the grinding wheel interferes with parts other than the cutting edge, resulting in a relatively wide area of unneeded parts. It also had the disadvantage of being processed. The present invention was made against this background, and an object of the present invention is to provide a drill honing method that can perform flat honing with high precision.

0004

[Means for Solving the Problems] In order to solve the above problems, in the present invention, a grinding wheel rotated around an axis is placed on the axially distal end side of a drill to be machined, and a grinding portion on a side surface of the grinding wheel is arranged to Then, while rotating the grinding wheel, the cutting edge at the tip of the drill was pressed against the grinding part to honing the drill.

[0005]

[Operation] According to the above structure, the cutting edge is honed along the planar rotation locus drawn by the grinding portion of the grinding wheel around the grinding wheel axis, so that flat honing can be performed. Moreover, since the grinding part on the side surface of the grinding wheel moves along the cutting edge, there is little possibility that unnecessary parts will interfere with the grinding part of the grinding wheel.

[0006]

Embodiment A honing method according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

First, the grinding machine used in this embodiment will be explained with reference to FIG. As shown in FIG. 5, the grinding machine 1 includes a base 2 placed on a floor, and a work head 3 and a grindstone head 4 provided on the base 2 and facing each other. The work head 3 is supported by a table (not shown) disposed on the base 2 and is movable in the X-axis direction and the Y-axis direction within a horizontal plane. Further, a work gripping section 5 is provided at the upper part of the work head 3. The workpiece gripping section 5 includes a workpiece rotation shaft 5a connected to a drive source (not shown) such as a motor, and a gripping mechanism (not shown) such as a collet chuck provided at the end of the workpiece rotation shaft 5a. It is configured to be able to grip the shank portion of the drill 6 to be processed and rotate the drill 6 around its axis O1 (equal to the Y-axis).

On the other hand, the whetstone head 4 includes a whetstone head 7 disposed on the base 2 and a spindle 8 supported by the whetstone head 7. The spindle 8 has a fitting part 8a formed at its tip to fit with the grinding wheel 9, and a drive motor (not shown) provided in the grinding wheel head 7.
It is made possible to rotate around the axis O2 by. In addition, between the grinding wheel head 7 and the base 2, the above-mentioned grinding wheel head 7
A grindstone moving mechanism 10 that changes the attitude of the grindstone is provided. This grindstone moving mechanism 10 includes a horizontal rotating table 11 mounted on a base 2, an elevating table 12 attached to this horizontal rotating table 11, and a vertical rotating table 13 attached to this elevating table 12. The horizontal turning table 11 is attached to the base 2 so as to be able to turn within a horizontal plane in the direction of arrow A in the figure, and the lifting table 12 is mounted in a direction perpendicular to the horizontal turning table 11 (orthogonal to the plane of the paper in FIG. 5). The vertical rotating table 13 is attached to the lifting table 12 so as to be pivotable in a vertical plane. The grindstone head 7 is attached to the vertical rotating table 13.

As shown in more detail in FIGS. 1, 3 and 4, the grinding wheel 9 has an annular core portion 14 having a center hole (not shown) into which the grinding wheel head 7 is fitted. A large number of hard brushes 15 are installed on the outer peripheral side, and the peripheral surface of these hard brushes 15 is used as a peripheral surface grinding part 15a, and the side surface is used as a side surface grinding part 15b, which can be used for grinding a workpiece. There is.

Next, the procedure for honing the drill 6 using the apparatus having the above configuration will be explained.
Prior to this, the drill 6 to be honed will be briefly described. As shown in detail in FIGS. 1 to 3, the drill 6 is made of cemented carbide and formed into a substantially cylindrical shape, and the wall surface of two spiral grooves 16 formed on the outer circumference and the tool tip relief Two cutting edges 18 are formed at the ridgeline portion with the surface 17. The cutting edge 18 is given a predetermined tip angle φ,
As a result, each cutting edge 18 is gradually retreated toward the rear end of the tool as it moves toward the outer circumference from the axis of the drill 6.

[0011]The honing of the drill 6 using the grinding machine 1 and grinding wheel 9 having the above configuration is performed according to the following procedure. That is, first, the drill 6 is mounted on the work rotation shaft 5a of the grinding machine 1, and the grinding wheel 9 is mounted on the spindle 8. At this time, as shown in FIG. 2, the drill 6 is positioned so that its cutting edge 18 extends in the vertical direction by operating the work rotation shaft 5a. In addition, the grinding wheel 9 is first held with the side surface grinding portion 15b perpendicular to the axis of the drill 6, but after that, the side surface grinding portion 15b is held parallel to the cutting edge 18 by the operation of the vertical rotation table 13. That is, as shown in FIG.
It can be tilted in the direction of falling down by 2.

[0012] Next, by operating the horizontal turning table 11, the grinding wheel 9 is caused to turn in the horizontal direction, and as a result, as shown in FIG.
is horizontally tilted by a predetermined honing angle θ with respect to the axis O1 of the drill 6. Note that in this state, it is of course tilted by 1/2 of (180-φ) with respect to the vertical direction. After adjusting the inclination of the grinding wheel 9 as described above, the grinding wheel 9 is rotated around the axis O1, the drill 6 is moved along the axial direction toward the grinding wheel 9, and the cutting blade 18, in the illustrated example, the cutting edge located below the drill axis is connected to the side surface grinding portion 15b.
to press against. In this case, the cutting edge 18 of the drill 6 and the grinding wheel 9
In order to contact the side surface grinding portion 15b of the drill 6,
The axial position and the vertical height of the grinding wheel 9 are adjusted by the table of the work head 3 and the lifting table 12 of the grinding wheel head 4, respectively.

According to the honing method described above, since the grinding wheel 9 is tilted horizontally by a predetermined honing angle θ with respect to the drill axis, the side surface grinding portion 15b is tilted horizontally with respect to the cutting edge 18. It rotates around the drill axis while drawing an annular plane tilted by the honing angle θ. Therefore, as shown in FIG. 4, the cutting edge 18 is formed with a flat honed portion 20 that is inclined by a predetermined honing angle θ. Moreover, in this case, the grinding wheel 9 is vertically (180-φ
), the honing part 20
The width is constant over the entire length of the cutting edge 18. Furthermore, since the side surface grinding section 15b moves along the cutting edge 18, the grinding wheel is more stable than when the peripheral surface grinding section 15a moves from the flank face of the drill 6 toward the rake face side or in the opposite direction as in the conventional case. There is little risk that the wheel 9 will interfere with parts other than the cutting blade,
There is also less possibility of grinding the drill 6 unnecessarily. In addition, when one cutting edge 18 is finished grinding, the drill 18 is
The grinding wheel 9 may be rotated by 80 degrees or the vertical inclination of the grinding wheel 9 may be reversed.

[0014] In the above embodiments, a case in which hard brushes 15 were installed as the grinding wheel 9 was particularly taken as an example, but the present invention is not limited to this, and grinding wheels of various configurations such as a buffing wheel can be used. obtain. Further, it is sufficient that the grinding portion is provided on the side surface, and it does not matter whether the grinding portion is provided on the peripheral surface or not. Further, the configuration of the grinding machine 1 is merely an example, and various configurations can be used as long as the positional relationship between the side surface of the grinding wheel and the cutting edge of the drill can be adjusted as in this embodiment. Furthermore, the drill to be processed is also 2
The drill is not limited to a single-blade solid drill, and may be a brazed one.

[0015]

[Effects of the Invention] As explained above, the present invention performs honing by pressing the cutting edge of the drill against the grinding portion on the side surface of the grinding wheel, so it is possible to perform flat honing with high precision. Moreover, it has the excellent effect of preventing interference between parts other than the cutting edge of the drill and the grinding part of the whetstone, thereby preventing unnecessary parts from being ground.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a state in which a grinding wheel is tilted to match the tip angle of the cutting blade.

FIG. 2 is a view taken from the direction II in FIG. 1;

FIG. 3 is a view taken from the direction of arrow III in FIG. 1;

FIG. 4 is an enlarged view of the drill tip during honing.

FIG. 5 is a plan view of a grinding machine used in an embodiment of the present invention.

[Explanation of symbols]

6 Drill 9 Grinding wheel 15b Side grinding part 18 Cutting blade 20 Honing part

Claims (1)

[Claims] [Claim 1] A grinding wheel that is rotated around an axis is disposed on the axially distal end side of a drill to be processed, with the grinding part on its side face facing the cutting edge of the distal end of the drill, and then A method for honing a drill, comprising honing the drill by pressing a cutting edge at the tip of the drill against the grinding part while rotating the grinding wheel.