JPH11216720A - Boring method of ceramic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily bore in a short period of time and improve the life of a grindstone by a method wherein a hole having a predetermined diameter is bored by means of a helical working, which is performed by helically pressing the rotating grindstone in after the grindstone is put into rotation. SOLUTION: On the hole 2 to be worked of a ceramic 1, a grindstone 3 is so constituted as to rotate the grindstone about a rotating shaft 4. The rotating grindstone 3 is pushed down with a driving device so as to bring the grindstone 3 into contact with the portion, in which the hole 2 to be worked is present, of the ceramic 1. Next, with the driving device, the grindstone 3 is pushed in and, at the same time, a helical working, which is carried out by helically moving same part of the outer peripheral part of the grindstone 3 into contact with the some part of the outer peripheral part of the hole to be worked at all times, is executed. Through the helical working, the predetermined hole 2 can be bored in the ceramic 1. Thus, since a hole is made in the ceramic through the helical working, the boring in the ceramic can be carried out easily in a short period of time and under the state that the life of the grindstone is kept longer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a hole in a ceramic by using a grindstone on the ceramic.

[0002]

2. Description of the Related Art Conventionally, when a hole is formed using a ceramic grindstone, first, as shown in FIG. 6A, a tool 51 set in an ultrasonic machine (not shown) is vertically vibrated by ultrasonic waves. Ultrasonic processing is performed by the loose abrasive grains 52 to form a pilot hole 54. Next, as shown in FIG. 6B, the grindstone 55 which can rotate is set in the prepared hole 54, and the whole set grindstone 55 is rotated little by little to form a hole 56 having a predetermined diameter. A predetermined hole is formed by performing a single-stage hole forming and performing a grinding process by a machining center that continuously performs the hole forming up to the bottom of the prepared hole 54. In addition, as another example of conventional hole drilling, as shown in FIG. 7, when a drill cycle process is performed by rotating a grindstone 61 and vertically moving a ceramic 62 to perform predetermined hole drilling. There was also.

[0003]

As described above, after a pilot hole is formed by ultrasonic processing, grinding by a machining center or drill cycle processing for raising and lowering a rotating grindstone is performed by a ceramic having a high hardness. This is because it is a brittle material. However, the conventional hole drilling method described above has a problem that the hole drilling process is complicated and takes time in the case of grinding with a machining center after ultrasonic drilling. There was a problem that the life of the grinding wheel could not be further shortened.

An object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide a method for boring a ceramic, which can be processed easily and in a short time and which can achieve a longer life of a grindstone.

[0005]

According to the present invention, there is provided a method of forming a hole in a ceramic, wherein a hole is formed by using a grindstone in the ceramic. It is characterized in that a hole having a predetermined diameter is formed by processing.

The present invention is based on the finding that a hole can be formed in a ceramic in a simple and short time and with a long life of the grindstone by forming a hole in the ceramic by helical processing. In other words, helical processing, in which a grindstone is rotated and the rotated grindstone is pushed in a helical manner, which has been partially used in metal processing but not used in ceramic processing at all, has been directly applied to ceramics. Holes can be machined.

In the present invention, in order to perform the drilling in an optimum state, when the diameter of the hole to be drilled is D and the diameter of the grindstone is d, the diameter of the hole to be drilled is equal to the diameter of the grindstone. The ratio D / d is preferably 1.3 or more from the viewpoint of the life of the grindstone and the like. In addition, it is preferable to rotate the grindstone at a high peripheral speed of 10,000 to 20,000 rpm, which is twice or more that in the conventional case, in helical processing because the processing efficiency increases. In that case, for example, since the abrasive grains made of diamond become high in temperature and the life is shortened, it is preferable to supply a high-pressure coolant between the grindstone and the ceramics during helical processing and cool it.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a view for explaining an example of a method for boring a ceramic according to the present invention. Referring to FIG. 1, the method for boring a ceramic according to the present invention will be described. First, as shown in FIG. 1A, a grindstone 3 is set on a hole 2 of a ceramic 1 to be processed. The grindstone 3 is configured such that the grindstone 3 itself is rotated about a rotation shaft 4 by a driving device (not shown). Next, as shown in FIG. 1B, the rotating grindstone 3 is pressed down by a driving device (not shown) so that the grindstone 3 is brought into contact with the portion of the ceramics 1 where the hole 2 to be machined exists. Here, the position of the grindstone 3 is not the center of the hole 2 to be machined, but a position where a part of the outer periphery contacts a part of the outer periphery of the hole 2 to be machined. Next, a helical process is performed by a driving device (not shown) in which the grindstone 3 is pushed in and, at the same time, the outer periphery of the grindstone 3 is spirally moved so that a part of the outer periphery always contacts a part of the outer periphery of the hole 2 to be machined. . By this helical processing,
As shown in (c), a predetermined hole 2 can be formed in the ceramics 1.

[0009] The above-described hole machining by helical machining of the present invention can be carried out easily and in a short time as compared with conventional machining center machining and drill cycle machining after ultrasonic drilling. The service life can be extended for the following reasons. First, since the helical machining can perform the hole machining only in one process, the number of processes can be reduced as compared with the conventional hole machining, and the hole machining can be performed easily and in a short time. Further, in helical processing in which a rotating grindstone is helically pushed, a load applied to the grindstone during drilling is reduced as compared with conventional drilling, and a longer life of the grindstone can be achieved.

Hereinafter, preferred embodiments of the processing conditions for carrying out the method for boring a ceramic of the present invention will be described. First, the relationship between the hole diameter to be machined and the grindstone diameter was investigated from the viewpoint of grinding resistance. As shown in FIG. 2, a diamond grindstone 11 having a diameter d = 3.5 mm is prepared, and the diameter D of the hole 12 to be machined is set to D = 4.1 mm.
Holes were actually formed in the alumina plate 13 by helical processing under the same conditions with the peripheral speed of the diamond grinding stone 11 and the rotation pushing amount being constant while changing to 62 mm, 4.95 mm, and 5.16 mm. Then, the relationship between the grinding amount and the grinding resistance in each hole processing was obtained. The results are shown in FIG. Here, the grinding amount is the volume of the alumina plate 13 actually ground, and the grinding resistance is the tip 11a of the diamond grinding stone 11.
Indicate the resistance received from the bottom 12a of the hole 12 respectively.

From the results shown in FIG. 3, when the diameter D of the hole 12 to be machined is D = 5.16 mm, 4.95 mm, 4.62 mm, the grinding resistance does not increase so much even if the grinding amount increases. It was found that when the diameter D of the hole 12 to be formed was D = 4.1 mm, the grinding resistance sharply increased as the grinding amount increased. From the above results, the diameter D of the hole to be machined
It has been found that it is preferable to set the ratio D / d to the diameter d of the grinding stone to 1.3 or more.

Next, the effect of increasing the peripheral speed of the diamond grinding wheel 11 was investigated. First, it was considered that the cutting depth g of the grindstone in the peripheral surface 11b of the diamond grindstone 11 in the helical machining was the same as in the case of the surface grinder. That is, as shown in the example of the surface grinding machine in FIG. 4, the peripheral speed of the diamond grindstone 11 is V, the interval between the abrasive grains 15 is a, the grindstone diameter is D, the feed speed of the alumina plate 13 is v, and the working thickness is V. Assuming that t is t, the abrasive grain cutting depth g is g = 2 at ^1/2 (1 /
D) ^1/2 (v / V). In the above formulas, it can be seen that when a, t, D, and v are constant, increasing the peripheral speed and increasing the peripheral speed V of the diamond grindstone 11 can reduce the abrasive grain cutting depth g.

In the case where the peripheral speed of the grindstone is increased and the cutting depth of the abrasive grains is reduced, the load applied to the abrasive grains can be reduced. If the load on the abrasive grains can be reduced, the grinding resistance can be reduced and the feed rate can be increased,
The grinding efficiency can be improved. In addition, when the load applied to the abrasive grains can be reduced, the wear of the grindstone decreases, and the life of the grindstone can be prolonged. From the above results, it is preferable to increase the peripheral speed of the grinding wheel from the viewpoint of improving the grinding efficiency and extending the life of the grinding wheel.
It has been found that it is preferable to perform helical machining at a peripheral speed of 000 to 20,000 rpm.

When the peripheral speed of the diamond grindstone is increased as described above, a larger amount of heat is generated than usual. Here, it is known that diamond abrasive grains are weak to heat. Therefore, it is preferable to provide a high-pressure coolant unit for cooling the diamond grindstone. FIG. 5 is a diagram showing a configuration of an example of a diamond grindstone having a coolant unit.

In the example shown in FIG.
a and a base 21b having a larger diameter than the tip 21a, a diamond electrodeposition part 22 in which diamond abrasive grains are provided by electrodeposition on the entire peripheral surface 21a-1 and the tip 21a-2 of the tip 21a, Reference numeral 23 denotes a through-hole for passing a coolant provided through the grindstone main body 21, and reference numeral 24 denotes a tip portion 21.
The slit 25 communicating with the through hole 23 provided in the entire radial direction of the tip 21 a-2 of a is a coolant supply device for supplying a coolant such as a grinding fluid to the through hole 23 through the pipe 26.

In this embodiment, the coolant is supplied to the tip 21a.
Any configuration is possible without being limited to the above configuration, as long as it can be ejected from the tip 21a-2 of the hole. However, the tip 21a-2 is always in contact with the bottom of the hole to be machined during helical machining. Therefore, merely providing the through-hole 23 in the grindstone main body 21 does not allow the coolant to be effectively ejected between the tip 21a-2 and the bottom of the hole to be machined. Therefore, in this example, by providing a slit 24 that communicates with the through hole 23 from the distal end 21a-2 of the distal end portion 21a, the coolant can be effectively ejected through the slit 24.

[0017]

As is apparent from the above description, according to the present invention, since the holes are formed by helical processing in the ceramics, the ceramics can be formed simply and in a short time while maintaining the life of the grinding wheel long. Holes can be machined. In other words, helical processing, in which a grindstone is rotated and the rotated grindstone is pushed in a helical manner, which has been partially used in metal processing but not used in ceramic processing at all, has been directly applied to ceramics. Holes can be machined.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an example of a method for boring a ceramic according to the present invention.

FIG. 2 is a diagram showing a state in which a relationship between a hole diameter to be machined and a grindstone diameter is obtained in the present invention.

FIG. 3 is a graph showing a relationship between a grinding amount and a grinding resistance in the present invention.

FIG. 4 is a diagram for explaining an abrasive grain cutting depth in a surface grinding machine.

FIG. 5 is a diagram showing a configuration of an example of a diamond grindstone having a coolant unit according to the present invention.

FIG. 6 is a view for explaining an example of a conventional method for boring a ceramic.

FIG. 7 is a view for explaining another example of a conventional method for boring a ceramic.

[Explanation of symbols]

Reference Signs List 1 ceramics, 2, 12 holes, 3 grinding stones, 4 rotating shafts, 11 diamond grinding stones, 11a tip, 11b
Peripheral surface, 12a bottom, 13 alumina plate, 15 abrasive grains, 2
1 wheel body, 21a tip, 21a-1 peripheral surface, 2
1a-2 Tip, 21b base, 22 electrodeposited diamond part, 23 through hole, 24 slit, 25 coolant supply device

Claims (5)

[Claims] 1. A method for boring a ceramic in which a hole is formed by using a grindstone in a ceramic, wherein a hole having a predetermined diameter is formed by helical processing in which the grindstone is rotated and the rotated grindstone is spirally pushed. Characteristic hole drilling method for ceramics. 2. The ratio D / d of the diameter of the hole to be machined to the diameter of the grindstone is 1.3 or more, where D is the diameter of the hole to be machined and d is the diameter of the grinding wheel. Item 6. The method for boring a ceramic according to Item 1. 3. The method according to claim 1, wherein the rotation of the grindstone is performed at a high peripheral speed. 4. A high peripheral speed rotation of the grinding wheel is 10,000.
4. The method according to claim 3, wherein the rotation speed is from 0 to 20,000 rpm. 5. The grindstone according to claim 1, wherein the grindstone has a coolant unit for cooling the grindstone, and a coolant is jetted between the grindstone and a processing hole to cool the grindstone during processing. Item 6. A method for drilling a hole in a ceramic according to the item.