JP2008044178A - Drilling method for plate material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drilling method which, in the case of providing circular holes for a plate material, is hard to cause the chipping-off, breakage and the like in the peripheries of the round holes and excellent in productivity. <P>SOLUTION: Provided is the processing method of perforating the round holes in the plate material comprising: forming first recess parts on one surface of the plate material using a first core drill having a tapered part in which the outer circumference of the head end part is decreased in diameter towards the tip of it; and providing a through-hole using a second core drill whose outside diameter is larger than the inside diameter of the first core drill and smaller than the diameter of the surface edge parts of the first recesses, from the other face of the plate material by making the drill concentrically face to the first core drill. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a processing method for drilling a circular hole in a plate made of a brittle material such as a ceramic substrate, a silicon substrate, or a glass substrate.

As a method of drilling a circular hole in a brittle material such as a ceramic substrate, a silicon substrate, or a glass substrate, a method of drilling from one side of a plate material using a core drill such as a diamond drill is known.
However, if a through-hole is drilled from one side of the plate material at once using a core drill, chipping and cracking are likely to occur around the hole.
Therefore, a method of drilling a recess that does not penetrate from one surface of the plate material using the first core drill and a bore that is concentrically opposed to the first core drill from the other surface using the second core drill. Various proposals have been made.
For example, in Japanese Patent Laid-Open No. 2000-158395, after forming a pilot hole on the lower surface of a plate material, when the upper hole is formed and communicated from the upper surface, the enlarged diameter portion provided on the drill for the upper hole is countersunk. However, when the upper hole drill communicates with the lower hole, there is a possibility that the communication portion may be cracked or a stepped portion due to misalignment may occur.
Such a problem is common when drilling circular holes in various brittle plate materials in the housing and automobile fields. However, disk substrates that rotate at high speed and receive vibrations are further dimensioned from the viewpoint of reliability. There is a need for a processing method that is highly accurate and does not cause chipping or cracking around the hole.

JP 2000-158395 A

  An object of the present invention is to provide a drilling method that is less prone to chipping, cracking, and the like around a circular hole when a circular hole is drilled in a plate material, and is excellent in productivity.

The hole processing method according to claim 1 is a processing method for drilling a circular hole in a plate material, and the plate material using a first core drill having a tapered portion whose outer periphery of the tip portion is reduced in diameter toward the tip portion. Forming a first recess on one surface, and using a second core drill whose outer diameter is larger than the inner diameter of the first core drill and smaller than the diameter of the surface edge of the first recess. And a step of drilling a through hole concentrically facing the first core drill from the other surface of the plate material.
Here, forming the first concave portion with the first core drill having the tapered portion at the distal end portion is intended to form the outer periphery of the first concave portion with the tapered portion.

The hole processing method according to claim 2 is a processing method for drilling a circular hole in a plate material, and using a first core drill having a tapered portion whose diameter is expanded toward the rear end side on the outer periphery of the drill portion. A step of forming a first recess in one surface of the plate member, and a second core drill having an outer diameter dimension larger than an inner diameter of the first core drill and smaller than a diameter of a surface edge portion of the first recess. And a step of drilling a through hole concentrically facing the first core drill from the other surface of the plate material.
Also in this case, the outer periphery of the first recess is formed by the tapered portion of the first core drill.

  In the present invention, the first core drill is provided with a tapered portion, and the first concave portion is formed so as to be formed by this tapered portion, so that a tapered surface that also serves as chamfering is formed at the surface edge portion of the concave portion of the plate material. For this reason, when the second core drill is used to make a through hole from another surface, the tip of the second core drill communicates with this tapered surface, and it is difficult for cracks and cracks to occur around the hole.

An example applied to a glass substrate used for a magnetic disk as an example of the hole machining method according to the present invention will be described below with reference to the drawings.
FIG. 1 shows a cross-sectional view of a perforated portion of the glass substrate 1 and schematically shows the appearance of the first core drill 2 and the second core drill 3.
The first core drill 2 has a tapered portion 2a whose outer periphery is reduced in diameter toward the distal end, and a cylindrical cavity 2b on the inner peripheral side.
Abrasive grain layers such as diamond particles are formed on the inner peripheral surfaces of the tapered portion 2a, the tip portion, and the cavity portion 2b of the first core drill 2.
As shown in FIG. 1A, as a first step, the first core drill 2 is rotated forward from one surface (lower surface) of the glass substrate 1, and the first recess 1a shallower than the thickness of the glass substrate 1 is obtained. To drill.
The first concave portion has a shape obtained by transferring the shape of the first core drill 2, and a tapered surface a is formed on the outer periphery of the first concave portion 1a by the tapered portion 2a of the first core drill.
The diameter of the glass substrate surface edge b of the tapered surface depends on the drilling depth of the first core drill.

In the second step, a second core drill 3 is used to drill from the other surface (upper surface) of the glass substrate 1 as shown in FIG.
The 2nd core drill 3 is a cylindrical drill which has the cavity part 3a inside, Comprising: It has an abrasive grain layer in a front-end | tip part and an inner peripheral part.
The outer diameter d ₂ of the second core drill 3 of the glass substrate surface edge b of the first recess 1a formed in the first smaller than the rear end side outer diameter d ₅ of the tapered portion 2a of the core drill, and a first step smaller than the diameter _{d 1.}
The outer diameter d ₂ of the second core drill 3 is larger than the inner diameter d ₃ of the first core drill 2, and the inner diameter d ₄ of the second core drill 3 is preferably smaller than the inner diameter d ₃ of the first core drill 2. .
When the second core drill 3 is drilled and the hole penetrates, the shape becomes as shown in FIG.
In this case, since the outer diameter d ₂ of the second core drill is smaller than d _{1 and} larger than d ₃ , the second core drill communicates with the tapered surface a and is less likely to cause chipping or cracking.
In addition, as a grinding method, even if a core drill moves up and down, a glass substrate may move up and down.

A second embodiment is shown in FIG.
The first core drill 12 has a cylindrical drill portion 12b and a tapered portion 12a whose diameter is increased toward the rear end on the outer periphery of the drill portion 12b.
The 1st core drill 12 has an abrasive grain layer in the front-end | tip part, an outer peripheral surface (12a, 12b), and the internal peripheral surface of the cavity part 12c.
As shown in FIG. 2A, as the first step, the first recess 11 a is drilled from the lower surface of the glass substrate 1 with the first core drill 12.
The 1st recessed part 11a has the taper surface a formed with the circular groove | channel formed with the drill part 12b, and the taper part 12a.
Next, as a second step, a second core drill 13 is used to drill from the upper surface of the glass substrate 1 as shown in FIG.
The 2nd core drill 13 has the taper part 13b expanded in the reverse direction to the front-end | tip part at the rear-end part of the drill part 13a.
The outer diameter _{d 12} of the second core drill 13 is smaller than the diameter _{d 11} of the surface edges b of the tapered surface a first recess 11a formed in the first core drill.
Further, from the outer diameter _{d 12} is the first core drill inner diameter is not necessarily great need than the outer diameter _{d 17} of the first core drill of the drill portion 12b is larger than _{d 13 d 12} is _{d 17} of the second core drill 13 If it is large, there will be no communication step on the inner peripheral surface of the hole as shown in FIG.
In the case of the embodiment shown in FIG. 2, chamfered portions are formed on both the lower surface and the upper surface of the glass substrate.

1 shows a first embodiment of a hole drilling method according to the present invention. 2 shows a second embodiment of the hole machining method according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass substrate 1a 1st recessed part 1b Drilling 2 1st core drill 3 2nd core drill

Claims (2)

A processing method for drilling a circular hole in a plate material,
Forming a first recess on one surface of the plate using a first core drill having a tapered portion whose outer periphery of the tip portion has a diameter reduced toward the tip portion;
A second core drill having an outer diameter larger than the inner diameter of the first core drill and smaller than the diameter of the surface edge of the first recess is concentrically opposed to the first core drill from the other surface of the plate. Forming a through hole; and
A method for drilling a plate material, comprising: A processing method for drilling a circular hole in a plate material,
Forming a first recess in one surface of the plate using a first core drill having a tapered portion whose diameter is increased toward the rear end on the outer periphery of the drill portion;
A second core drill having an outer diameter larger than the inner diameter of the first core drill and smaller than the diameter of the surface edge of the first recess is concentrically opposed to the first core drill from the other surface of the plate. Forming a through hole; and
A method for drilling a plate material, comprising:

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