JPS5852782B2 - Grinding method for dental ultra-fine square cutting tools - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of grinding and forming an ultra-fine square cutting tool, such as a cutting edge of a dental square broach or reamer, which enables mass production.

This type of square broach is used on the tooth treatment area by wrapping thin absorbent cotton soaked in a dental nerve anesthetic or disinfectant around the blade, and the square reamer is a square or triangular It is made by twisting an elongated blade with a cross-sectional shape of , and is used to cut and enlarge the nerve hole of a tooth.

Therefore, the blades are required to be extremely thin and sharp, and are also desired to be of excellent quality, stable, and low profile.

Conventionally, such square broaches or reamers (hereinafter simply referred to as broaches) have 0, I
It has an extremely thin rectangular shape of 1 to 0.4 x 0.4 mm or a triangular shape of 0.3 to 0.771 L7IL on one side, and is created by drilling on the groove of the block as shown in Figure 2. Place the round bar material gripped with a chuck, etc., and
The wheels were rotated by 120 degrees or 120 degrees, and the wheels were ground one by one into a square or triangular shape using a grinding wheel.

Therefore, it was not possible to meet the demand for increased production or to supply products of stable quality, and it was not possible to reduce prices.

The present invention has been made to improve this point, and consists of chucking a large number of rectangular broach materials at once using a special chuck device, placing them in the rotating direction on the outer circumferential surface of these relatively wide grinding wheels, and A pressing block having a pressing surface formed like a surface is ground by applying an appropriate load, thereby making it possible to grind and form the blades of a large number of rectangular broaches at the same time.

An embodiment of the present invention will be described below with reference to the accompanying drawings.

1 is an ultra-fine rectangular broach for dental use, and 3 is a recess extending from the blade portion 2 to a tapered part of the handle.

The material shown in FIG. 1a has a blade part 2 formed by grinding with a diameter of 0.
It is an extremely thin square with a width of 1 to 0.4 mm, but the diameter of the handle is 0.
Since the bowl is thick (about 8 inches), it takes a lot of time to finish it by grinding it, so the parts other than the handle are ground in advance using a grinder specifically designed for thin items.

Of course, it is also possible to form the blade part by grinding without providing a tapered part following the handle part, and this is adopted in the case of square reamers and the like.

Reference numeral 4 designates a rotatable chuck device for chucking the rectangular broach material used exclusively in the grinding method of the present invention, and 5 designates a material suppressing device for finishing the material by grinding it on the outer circumferential surface 7 of the grinding wheel 6.

Next, the reason why a large number of rectangular broaches are all formed by grinding at the same time on the outer peripheral surface of the grinding wheel will be explained.

In FIG. 4, since the grinding wheel 6 is required to rotate at a low speed for reasons described later, normal dressing using a diamond dresser is not possible. Make sure to dress the surface.

As a result, the polished surface of the outer peripheral surface inevitably has undulations 8 of several to several tens of microns in size.

Therefore, when the suppression block 9 is pressed against the outer circumferential surface 7 of the grindstone having the undulations 8 and polished, a pressing surface 10 having undulations and depressions corresponding to the undulations 8 is formed. Ru.

In this case, a part of the circular arc of the outer peripheral surface 70 of the grinding wheel is formed on the pressing surface 10, but in reality, the grinding wheel 6 is of a considerably large diameter, and the thickness W of the pressing surface 10 is It is sufficient to set the blade length to be larger than the blade length of the square cutting tool, so it can be regarded as a straight line.Moreover, in reality, the suppression surface 10 and the grinding surface 8 of the grindstone have a curvature of the radius of the grindstone, but the material 11 is thinner. Therefore, the curvature of the radius of the grindstone is sufficient and does not adversely affect the square cutting edge formed by grinding.

Next, the pressing block 9 is pulled upward, and a small round bar material 11 is held between its pressing surface 10 and the outer peripheral surface 7 of the grindstone.

In this case, even if there are undulations 8 on the outer circumferential surface 7, the pressing surface 10 is ground to correspond to the undulations 8, so that at any point on the outer periphery 7, The distance from the pressing surface is constant, and a large number of the materials 11 can be reliably held.

Therefore, the material 1 is compressed and held between the pressing surface 10 and the outer circumferential surface 7.
1 can be ground uniformly, making it possible to mass-produce rectangular broaches.

In this case, even if some of the materials 11 have some variation in shaft diameter, when using the above grinding method,
Since grinding is concentrated on the material with the largest shaft diameter, all the materials held together have the same finish.

Next, the pressing device 5 will be explained.

The suppression device 5, due to its own weight such as the suppression block 9,
A material 11 placed on the outer circumferential surface T of the grindstone 6 in the rotation direction thereof
A suitable pressure is applied to grind the material 11 to form the blade part 2 and give the blade part 2 a predetermined angle of inclination.

The suppression block 9 is removably installed on the pressurizing slide block 12, making it possible to grind not only the cutting edge of a rectangular broach but also other shapes.

The pressure slide block 12 slides up and down in a slide groove 15 provided in an upright portion 14 of a right angle angle 13 whose inclination is adjustable.

The pressing flock 9 constantly applies an appropriate pressure to the material 11 by the force of a pressing spring, which will be described later, and the weight of the pressing slide block 12 and the pressing block 9, so as to apply a minute amount of grinding to the material 11.
Add to.

For this reason, it is necessary for the pressure slide block 12 to slide up and down in the slide groove 15 very easily, and as shown in FIGS. 3 and 5, for example, three bearings 16 are provided on the back surface of the block 12. , the intermediate bearing is laterally elasticized by the spring 18, and these 3
The pressure slide block 12 slides easily in the slide groove 15 by the bearings.

Further, a spring 17 provided between a bearing provided in front of the slide block 12 and an upright portion 14 of the angle 13 is used to elastically press the slide block 12 so that the slide block 12 slides without jumping out of the slide groove 15.

Furthermore, in order for the slide block 12 to apply the above-mentioned appropriate pressure to the materials 11 placed in large numbers on the outer circumferential surface 7 of the grindstone during grinding, a spring holding piece 20 and a slide block are provided above the upright portion 14 of the right angle angle 13. Spring 19 between the tops of 12
hang it up.

The right angle angle 13 is tiltably attached to the base plate 21 by adjustable screws 31, 32 and a fulcrum pin 29.

Next, the rotary chuck device 4 will be explained.

The device 4 securely grips a large number of materials 11 to be ground,
Rotating the material itself or rotating the device itself,
This is a special rotatable chuck device suitable for grinding and forming the blade part of square cutting tools.

This device has comparatively wide gripping bodies 22 and 23 so as to be able to grip a large number of small diameter round bar materials 11, and a gripping vice opening 22' thereof.

Thin pieces 24, 24 made of urethane rubber or the like, which are elastic and have a large coefficient of friction, are attached to the contact surface of 23'.

The reason is that when slight variations in the diameter of the handle of the material 11 are absorbed, one of the vise openings 22' and 23' is moved relative to the other, and the material 11 is rotated to achieve a grinding finish. , in order to ensure that rotation, the pythro section 2
This is to prevent each material 11 held between 2' and 23' from stretching in the lateral direction.

The gripping state is shown in FIG. The gripping bodies 22 and 23 or the vice openings 22' and 23' can be tightened by appropriate means, such as a suppression lever with a cam portion at the tip (not shown).
Do it equally.

At a suitable place on the opposite end of the gripper 22.23 from the vice-throttle part,
V-shaped receiving grooves 25 and 26 are provided for inverting the chuck device 4 by 180 degrees on the substrate.

The chuck device 4 is placed on a chuck device support member 27 fixedly provided on the substrate 21 in the receiving groove 26 .

As will be described later, the receiving groove 25 is formed when the chuck device 4 is rotated 180 degrees and turned over in order to grind the other side corresponding to the tucking after grinding one side of the rectangular shape of the blade of the square cutting tool. The chuck device 4 is placed on the member 27.

Since the rectangular blade portion formed by grinding is extremely fine, the setting of the support member 27 is parallel to the X-axis, Y-axis, and Z-axis directions with respect to the suppressing device 5 described above. If the blades are not parallel, the blade portion formed by grinding may become curved and deformed, resulting in poor grinding, so it is necessary to pay sufficient attention to this.

Next, the formation of the shape of the pressing surface 10 of the pressing block 9 will be explained.

When using the grinding method according to the present invention, a square cutting tool is formed by grinding simply by pressing and holding the grinding material 11 on the outer circumferential surface 7 of the grinding wheel 6 with the pressing blocks 9.

By the way, as shown in Figs. 1 and 1C, the rectangular broach 1 has the shaft diameter of the material 11 as its handle, and a relief 3 from a continuous taper part (this part does not necessarily have to be provided). As a result, the blade portion 2 is formed to have a slight inclination angle, and in practice, the relief 3 is ground to have an inclination angle of approximately 2.5 degrees, and the blade portion 2 is ground to have an inclination angle of approximately 0.5 degrees.

Therefore, the suppression surface 10 is simply pressed against the outer circumferential surface 7 through the grinding material 11 to form the relief 3 and the blade portion 2 having a slight inclination angle by grinding. It is necessary that the shape of the entire blade portion having these inclination angles is configured to correspond to each other.

(Since the relief 3 is just a relief, the relief 3 of the pressing surface 10
A portion corresponding to the blade portion 2 is not necessarily necessary, and a portion corresponding to the blade portion 2 alone is sufficient, and in this case, the relief 3 will be naturally formed in a portion off the pressing surface.

However, the following is an example in which a portion of the pressing surface 10 corresponding to the relief 3 is formed.

) Therefore, to explain the order of forming the above-mentioned inclination angle on the suppression surface 10, first, the right angle angle 13 is rotated around the rotation center 28, 2B defined at the right angle part.

The center of rotation 28.28 has fulcrum pins 29 on both sides of the angle.
29 (FIG. 5), and the fulcrum pins are fitted and set into the bearings 30, 30 provided on the board 21, respectively.

Adjust the bottom part 14' of the right angle 13 to the appropriate position 31
, 32 are provided, and the thread 31 passes through the bottom part 14' and connects to the substrate 2.
1, screw 32 into the bottom part 14',
The tip thereof is pressed against the substrate 21 and the two are adjusted to determine the inclination angle of the right angle 13.

An example thereof is shown in FIGS. 7a and 7b.

In figure a, when adjusting the screws 31 and 32 while looking at the scale of a dial indicator etc. provided separately, and tilting the right angle 13 2 degrees backward from the center of rotation 28 with respect to the running direction of the grinding wheel surface, the suppression will occur. Since the block 9 is integrated with the right angle angle 13 via the slide block 12, the front end γ of the suppression block 9 has an inclination angle of 2 degrees.
It is ground by a grindstone 6.

Next, as shown in Figure b, when the right angle 13 is returned to its normal position and tilted forward by 0.5 degrees with respect to the running direction of the grinding wheel surface, the front end g' of the pressing block (the remainder of the pressing surface 10) becomes It is formed by grinding with an inclination angle of 0.5 degrees.

That is, the rear end 94 has an inclination angle of 2.5 degrees, and the front end 94 has an inclination angle of 0.
．． It will have an inclination angle of 5 degrees, and the inclination angle of the relief 3 and the blade part 2 of the square broach will be ground and formed on the suppression surface 10, and the predetermined shape of the square broach will be formed by grinding.

Moreover, as described above, since the outer circumferential surface 7 and the pressing end 10 of the grindstone 6 have the same shape and correspond to each other, it is possible to grind a large number of square broaches with a predetermined shape at the same time.

Next, the order of grinding the blade portion of a rectangular cutting tool using the above-mentioned rotary chuck device 4 and pressing device 5 will be explained.

In FIG. 8, a shows the order of the grinding process for a square-shaped cutting tool, and b shows the grinding process order for a triangular-shaped cutting tool.

In Fig. a, first, a circular material 11 is gripped by the chuck device 4 so that one side of a rectangle is obtained, and the eye portion is ground by the grinding wheel 6 and the suppressing device 5.

Next, the chuck device 4 is rotated 180 degrees and turned over, and the portion is ground to form the second side, which is the opposite side.

To form the third side of the quadrangle by grinding, grind one side of the workpiece to the other while keeping the second side formed, that is, while holding the workpiece 11 between the vise openings 22' and 23' as described above. 11 is rotated by 90 degrees and the two parts are ground and formed.

To form the remaining fourth side of the quadrangle, the third side is ground and the chuck device 4 is turned over again by 180 degrees and the water portion is ground.

In this case, for example, if the angle of inclination of the blade part 2 is to be ground to 1.0 degrees (in increments of 0.5 degrees from the axis), the pressing surface 10 is initially inclined by 0.5 degrees and the eye portion on the -th side is ground. However, when grinding the second side, it is desirable to tilt the suppressing surface 10 by 1.0 degrees.

However, in actual grinding, it is time-consuming to change the inclination angle of the suppression surface 10 each time, so as an example of a simpler method, the inclination angle of the suppression surface 10 is fixed and the material is prepared as shown in Figure 8a. After grinding the first, second, third, and fourth sides in order to form a square shape, the fourth, third, second, and first sides are ground in the reverse order to obtain an inclination angle that is approximately the same as the desired inclination angle. It is possible to grind the blade portion 2 having a .

In the case of figure b, the shape is triangular (for example, one side is 0.4 to 0.7 m)
This is a tool that grinds and forms a cutting tool (of RTT).A circular material is ground to form one side of an equilateral triangle, and then this is
The paper is rotated 0 degrees to grind the second side, and the remaining third side is formed by grinding the paper with the second side ground by further rotating the paper 120 degrees.

In reality, instead of rotating the paper 120 degrees, the rotation is shifted by 60 degrees and the chuck device 40 is reversed.

This allows the rotational shift angle to be set to V3, which has the advantage of improving angle indexing accuracy.

Now, a method of grinding and forming a rectangular cutting tool will be described using the grinding and forming apparatus and the grinding order as described above.

First, the pressing device 5 is moved along the X-axis, Y-axis, and Z-axis relative to the position of the grinding wheel 6.
The axes are set to the substrate 21 so that they match correctly.

Next, the rotary chuck device 4 is set so that its three axes, XYZ, are correctly parallel to those of the suppressing device 5, as described above.

Next, the outer circumferential surface 7 of the grinding wheel 6 is dressed with another grinding wheel rotating at high speed.

The suppressing surface 10 of the suppressing block 9 is ground by the outer circumferential surface 7 to give the suppressing surface 10 a surface corresponding to the shape (profile) of the outer circumferential surface 7.

Adjustment pins 31 and 32 adjust the right angle 130 of the suppressing device 5, and the pressing surface 10 is ground to provide an inclination angle necessary for forming the blade portion of the rectangular broach 1.

The suppressing block 9 having the suppressing surface 10 thus formed is pulled up together with the slide block 12 against the spring 19, and the grinding portion of the ultra-fine round bar material is placed between the suppressing surface 10 and the outer circumferential surface 7 of the grinding wheel. Make sure to maintain appropriate spacing to allow insertion.

Next, a large number of the portions of the material 11 that will become the handle are held side by side between the vice openings 22' and 23' of the rotary chuck device 4 via thin pieces of urethane rubber 24°24, and the gripping bodies 22°23 are tightened. The material 11 is mounted on the chuck device 4, and the outer portion of the chuck device 4, which becomes the blade portion of the material 11, is placed and held on the outer circumferential surface 7 of the grinding wheel 6 along its rotating direction.

At this time, it is important that the material 11 is securely clamped by the chuck via the urethane rubber thin pieces 24, 24.

Once the material 11 has been placed on the outer circumferential surface 7 as described above, when the force that was pushing the pressurizing slide block 12 upward is released, the suppressing surface 10 having a predetermined inclination angle is A large number of materials 1 are placed side by side on the outer peripheral surface 7
Press 1 all at once with appropriate pressure.

Next, when the grindstone 6 is rotated, grinding is started.

In this case, the thickness W of the pressing surface 10 is formed to be smaller than the size of the grindstone 6 used, so it can be seen as almost a straight line, and the grinding material 11 can be shaped into a predetermined blade shape without any movement. Can be formed by grinding.

Note that the grinding material 11 is 0. IXo, 1~0.4×0.4
Since the blade is ground into a small prismatic blade of mm size, if the amount of grinding is excessive, high grinding heat will be generated even in wet grinding, and the object to be ground will be deformed during grinding. It is important to grind with the same amount, and the spring pressure 19 is adjusted to adjust the pressure of the pressurized slide block 12. A bearing 16 is provided on the sliding surface.

At the same time, the rotation of the grindstone 6 (either counterclockwise or clockwise) is made low to minimize the amount of grinding.

Although the above description has been made regarding a square-shaped cutting tool, the same applies to triangular-shaped cutting tools and other cutting tools.

As described above, when using the method for grinding the blade part of a rectangular cutting tool according to the present invention, the pressing surface of the material pressing block is ground with the outer circumferential surface of the grinding wheel, and the shape (profile) is the same and corresponding to the outer circumferential surface of the grinding wheel. Since the grinding material is held and ground between the pressing surface and the outer circumferential surface of the grindstone, no matter how uneven the outer circumferential surface is, the blade portion with a predetermined inclination angle can be As a result, it is possible to grind and mass-produce the blade portion of a rectangular cutting tool, and it is possible to provide a low-profile rectangular broach or reamer with stable quality and excellent quality.

[Brief explanation of the drawing]

FIG. 1 shows an external view of a square broach formed by grinding by the method of the present invention, where a is the material to be ground, and C
2 is an explanatory diagram of the conventional method for grinding a square broach. FIG. 3 is an explanatory diagram of the grinding device used in the grinding method of the present invention. An explanatory diagram showing the principle of the grinding method, Fig. 5 is an explanatory diagram of the suppressing device of the above-mentioned grinding device, Fig. 6 is an explanatory diagram when the grinding material is held between the rotating chuck device, and Fig. 7 is an explanatory diagram of the suppressing device of the pressing device. FIG. 8 is an explanatory diagram showing the case where an inclination angle of a square broach is given to the end, and FIG. 8 is an explanatory diagram showing the order of grinding and forming the blade part of a square cutting tool. 1: Square broach, 2: Its blade, 3: Relief, 4: Rotating chuck device, 5: Pressing device, 6: Grinding wheel, 8: Waviness-like unevenness, 9: Pressing block, γ. 9": Its front end, rear end, 10: Pressing surface, 11: Grinding material, 12: Pressure slide block, 13: Right angle, 14, 14': Upright part, bottom part, 15 Ni-Ride groove, 16: Bearing, 17°18.19: Spring, 2
0: Spring holding piece, 21: Substrate, 22, 23: Material gripping body, 22.23': Gripping vise opening, 24: Urethane rubber, 25, 26: Receiving groove, 27: Chuck device support member, 28: Rotation Center, 29: Fulcrum pin, 30: Bearing, 31
, 32: Adjustment.

Claims (1)

[Claims] 1. A dental cutting tool in which the suppressing surface of a pressing block that operates only in the pressing direction is ground into the same shape as the outer peripheral surface of the grinding wheel using a grinding wheel, and then the suppressing surface is ground in a fixed direction of the grinding wheel surface. A method for grinding an ultra-fine rectangular dental cutting tool, characterized in that the material to be ground is pressed against the outer circumferential surface of a grindstone by the pressing surface of the pressing block after being tilted by an inclination angle of .