JPH04244382A - Diamond core drill - Google Patents

Abstract

PURPOSE:To provide a diamond core drill suited for use of high accurate and high quality drilling work relating to a work difficult material of ceramics or the like. CONSTITUTION:After chamfering is applied to internal and external peripheral sides in a point end of a pipe material 1, diamond abrasive grains 2 are fixed to the internal/external peripheries in a point end part of the pipe material by the electroplating method. Height H of a diamond abrasive grain electrodeposition range in the internal peripheral side is formed almost equal to a drill diameter D1, and height (h) of the similar electrodeposition range in the external peripheral side is set to almost 1/4 to 1/2 times the drill diameter D1. A sum of chamfering amounts c1, c2 is set to almost 2/3 thickness of the pipe material, and a chamfering angle theta is set to almost 25 to 45 deg..

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diamond core drill suitable for drilling holes in difficult-to-process materials such as ceramics.

0002

[Prior Art] In recent years, the need for micro-drilling has increased mainly in the field of electronic component processing, and mechanical methods using drills, physical methods using electron beams or laser beams, and chemical methods using etching have increased. Various drilling methods have been put into practical use.

However, the most commonly used method is a mechanical method using a drill. There are various types of drills used for this, such as twist type, boring type, and core type, and each type is used depending on the workpiece, purpose, etc.

According to the drilling method using a twist type or boring type drill, a hole 21 as shown in FIG.
is directly drilled, and all material inside the hole 21 is discharged as chips during machining.

On the other hand, a core-type drill (core drill)
According to the drilling method using a hole groove 22 as shown in FIG. 6, a core 23 remains inside, so by removing the core 23 by some method, A desired hole 24 as shown in 7 is obtained.

As described above, the drilling method using a core drill has the problem that a core remains and must be removed, but it has the advantage that less material is removed as chips. This means that the load on the drill is light, which is particularly advantageous when the workpiece is a difficult-to-process material such as ceramics, and extends the life of the drill. For these reasons, drilling using a core drill is attracting attention.

[0007] As a core drill particularly suitable for drilling in difficult-to-process materials such as ceramics, there is a diamond core drill in which diamond abrasive grains are attached to the surface of a pipe material. This can be divided into electrodeposition type and metal bond type depending on the manufacturing method. The electrodeposition type has diamond abrasive grains attached (electrodeposited) to the pipe material by electroplating, and the metal bond type has diamond abrasive grains attached by powder sintering. FIG. 8 shows the general manufacturing process of an electrodeposition type diamond core drill.

[0008] The electrodeposition type has a single layer of diamond abrasive grains attached, and its service life ends when the abrasive grains wear out. On the other hand, the metal bond type has a large number of sintered diamond abrasive grains, so it has an advantage over the electrodeposition type in terms of life. However, from the perspective of drilling performance, the electrodeposition type is superior (with the electrodeposition type, the diamond abrasive grains are well-protruded and sharp, while with the metal bond type, the diamond abrasive grains are buried in the binding material). It is often used for high-precision, high-quality drilling.

[0009]

[Problems to be Solved by the Invention] As mentioned above, diamond core drills are particularly suitable for drilling difficult-to-process materials such as ceramics, but the quality of the drill depends on high precision and high quality drilling. It greatly affects the finish of processing. In particular, it is difficult to maintain the quality of drills with a small diameter of 2 mm or less, and it is difficult to obtain good quality drills.

The performance of an electrodeposition type diamond core drill is greatly influenced by the quality of electrodeposition of diamond abrasive grains. In particular, the smaller the diameter, the more uneven electrodeposition of diamond abrasive grains occurs, making it difficult to obtain a high-quality drill. This uneven electrodeposition is
This occurs particularly noticeably on the inner circumferential side of the pipe material used as the drill material.

Further, as a result of experimental investigation, it has been found that the shape of the drill tip is an important point in performing high-precision, high-quality drilling. However, in the conventional core drill, since the shape of the tip is not specified, there are cases where it is not possible to perform high-precision, high-quality drilling due to a defect in the shape of the tip. That is, problems such as chipping around the hole and breakage of the drill tend to occur due to the poor shape of the tip. Such problems were noticeable in small diameter drills.

SUMMARY OF THE INVENTION An object of the present invention is to provide an improved diamond core drill suitable for high-precision, high-quality drilling in consideration of the above points.

[0013]

[Means for Solving the Problems] The present invention achieves the above object by appropriately defining the shape of a diamond core drill, particularly the shape of the important tip portion.

That is, according to the invention of claim 1, in a diamond core drill in which diamond abrasive grains are attached to the outer periphery and inner periphery of the tip portion of the pipe material, the tip of the drill in the area where the diamond abrasive grains are attached on the outer periphery side. The height from the tip of the drill is determined to be approximately equal to the diameter of the drill, and the height of the diamond abrasive grain attachment range on the inner circumferential side from the tip of the drill is approximately 1/4 to 1/2 of the diameter of the drill. determined.

According to the invention of claim 2, in the diamond core drill in which diamond abrasive grains are attached to the outer and inner circumferences of the tip portion of the pipe material, the inside of the tip of the pipe material is attached before the diamond abrasive grains are attached. Chamfering of a predetermined amount and a predetermined angle is performed on the circumferential side and the outer circumferential side.

According to the third aspect of the invention, in the diamond core drill according to the first aspect of the invention, chamfering of a predetermined amount and a predetermined angle is performed on the inner circumferential side and the outer circumferential side of the tip of the pipe material.

According to the invention of claim 4, in the diamond core drill according to the invention of claim 1 or 3, the sum of the amount of chamfering on the inner circumferential side and the outer circumferential side is approximately 3 of the wall thickness of the pipe.
It is considered to be 2/2.

According to the invention of claim 5, in the diamond core drill according to the invention of claim 4, the chamfer angles on the inner circumferential side and the inner circumferential side are approximately 25 to 45 degrees.

[0019]

[Operation] According to the invention of claim 1, the height of the diamond abrasive grain adhesion range on the inner and outer peripheries is properly defined, so that
Core breakage during machining is less likely to occur, high-quality hole machining is possible, and drill life is extended.

[0020] According to the second or third aspect of the invention, by rounding the tip of the drill, the biting of the drill at the start of machining becomes good, making it possible to perform highly accurate and high-quality drilling. In addition, since the drill has good bite and drilling can be started smoothly, the burden on the drill tip at the start of machining is reduced and the life of the drill is extended.

According to the invention of claim 4 or 5, chamfering is particularly effective, and it is possible to perform high-precision, high-quality drilling in difficult-to-process materials such as ceramics. Long drill life can be obtained.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. FIG. 1 is a vertical cross-sectional view showing the overall shape of an electrodeposited diamond core drill (hereinafter simply referred to as a drill) according to the present invention in a completed state, and FIG. 4 is an enlarged vertical cross-sectional view of the tip portion of the drill. In both figures, the dimensions of each part are defined as follows. L: Overall length of the drill d1: Outer diameter of the pipe material d2: Inner diameter of the pipe material H: Height of the diamond abrasive grain electrodeposition range on the outer circumference from the drill tip h: Height of the diamond abrasive grain electrodeposition range on the inner circumference side from the drill tip Height D1: Drill outer diameter D2: Drill inner diameter C1: Outer chamfer amount C2: Inner chamfer amount θ: Chamfer angle

The manufacturing process of this drill is basically the same as that of a conventional electrodeposition type diamond core drill, and is shown in FIG.
This can be illustrated by a flowchart. First, the tip of a pipe material 1 as a drill material as shown in FIG. 2 (longitudinal cross-sectional view) is chamfered as shown in FIG. 3 ("pipe processing" in FIG. 8).

Next, diamond abrasive grains 2 are electrodeposited on the inner and outer peripheries of the tip portion of the pipe material 1 after the chamfering process by electroplating as shown in FIG. 4 ("electrodeposition" in FIG. 8). Following this, in order to increase the adhesion strength of the diamond abrasive grains 2, as shown in the cross-sectional view in FIG. The plating layer 4 is overlaid.

Note that in order to regulate the heights H and h of the electrodeposition range of the diamond abrasive grains 2, a means usually called masking is used. That is, before electrodeposition, the pipe material 1
The outer and inner peripheries are covered with an insulating material such as rubber, leaving only the diamond abrasive electrodeposited area exposed.

Taking the case of a small diameter drill such as D1=2 (mm) as an example, the results of an experimental investigation of the dimensional specifications suitable for performing high-precision, high-quality drilling are as follows. That's right. L: 30 (this is an example) d1: 1.81±0.01 d2: 1.45±0.02 H: 2±0.1 h: 0.5-1 (approximately H/4-H/2 )C1=C
2: Approximately (d1-d2)/3 θ: 25 to 45 Diamond abrasive grain size: 200 mesh Note) The unit of θ is degrees, other units are mm

The basis for the above specifications will be explained below. The total length L of the pipe material 1 may be selected as necessary, and is not a particularly problematic amount. Outer diameter d1 and inner diameter d of pipe material 1
2 is important because it relates to the amount of chips during drilling. In the case of a small diameter drill such as D1 = 2 (mm), the pipe material 1 should be as thin as possible, and according to experiments, the range of approximately 0.1D1 < (d1 - d2) < 0.3D1. It was appropriate to choose That is, a thinner wall means less cutting chips, which has the advantage that the load on the electrodeposited diamond abrasive grains 2 is lighter and the life of the drill is longer.

Next, it is preferable that H be approximately equal to D1, and it is not good if it is too large or too small compared to D1. It has been experimentally confirmed that high-quality processing is possible within the above range of h. It was confirmed that if h is too large, the core that should remain during processing is likely to break, while if h is too small, the life of the drill will be shortened.

Furthermore, important points for high precision and high quality hole machining are the amount of chamfering C1 at the tip of the pipe material 1;
It is C2. If C1 and C2 are not present (without chamfering) or if C1 and C2 are too large, good hole drilling will not be possible, and if C1 and C2 are within the above range, very good hole drilling will occur. It was confirmed that processing is possible. In other words, by giving the tip of the drill a roundness due to this chamfer, the so-called "bite" at the start of drilling is good, the drilling is performed smoothly, and the core does not break during drilling. It was possible to perform high-precision, high-quality drilling over a long period of time. The chamfer angle θ was preferably within the above range, particularly around 30±5 degrees.

Using the drill of this example, under the following machining conditions:
It was possible to successfully drill more than 00 holes. The number of holes that can be machined with a conventional similar drill is 10 to 10.
Since there were only about 0 pieces, this means that the lifespan was more than 5 times longer. Processing conditions Workpiece: Ceramics Drill rotation speed: 10,000 rpm Drill cutting speed: 15 mm/min Hole specifications: Blind hole with a diameter of 2 mm and a depth of 4 mm

Note that the same effect can be obtained even if the shape of the chamfered portion is an arcuate shape that satisfies the specified amount.

[0032]

According to the first aspect of the invention, core breakage during machining is less likely to occur, high-quality hole machining is possible, and the life of the drill is extended. According to the invention of claim 2 or 3, the biting of the drill at the start of machining becomes good, making it possible to perform high-precision, high-quality drilling. Additionally, since drilling can be started smoothly, the load on the drill tip at the start of machining is reduced, and the life of the drill is extended. According to the invention of claim 4 or 5, the chamfering of the tip of the pipe material is particularly effective, and it is possible to perform high-precision, high-quality drilling in difficult-to-process materials such as ceramics. Long drill life can be obtained.

As described above, according to the present invention, it is possible to provide an excellent diamond core drill that is suitable for high-precision, high-quality drilling in difficult-to-process materials such as ceramics, and has a long life.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the overall shape of a diamond core drill according to the present invention.

FIG. 2 is a longitudinal cross-sectional view showing the shape of a pipe material used as a material for the drill before processing.

FIG. 3 is a longitudinal cross-sectional view showing the shape of the tip of the pipe material after being chamfered.

FIG. 4 is an enlarged vertical cross-sectional view of the tip of the drill.

FIG. 5 is a cross-sectional view showing the shape of a hole drilled by a twist type or boring type drill.

FIG. 6 is a cross-sectional view showing the shape of a hole drilled by a core drill.

FIG. 7 is a cross-sectional view showing the shape of a hole after removing the core remaining after drilling with a core drill.

FIG. 8 is a flowchart showing the manufacturing process of an electrodeposition type diamond core drill.

[Explanation of code] 1 Pipe 2 Diamond abrasive grain 3 Plating layer 4 Plating layer

Claims (5)

[Claims] Claim 1: In a diamond core drill in which diamond abrasive grains are attached to the outer and inner circumferences of the tip of a pipe material, the height from the tip of the drill to the area where the diamond abrasive particles are attached on the outer circumferential side is defined as the diameter of the drill. A diamond core drill characterized in that the height of the diamond abrasive grain adhesion range on the inner peripheral side from the tip of the drill is set approximately equal to 1/4 to 1/2 of the diameter of the drill. . [Claim 2] In a diamond core drill in which diamond abrasive grains are attached to the outer and inner circumferences of the tip of a pipe material, the diamond abrasive grains are attached to the inner and outer circumferential sides of the tip of the pipe material before the diamond abrasive grains are attached. A diamond core drill characterized by chamfering at a fixed amount and at a predetermined angle. 3. The diamond core drill according to claim 1, wherein the outer circumferential side and outer circumferential side of the tip of the pipe material are chamfered by a predetermined amount and at a predetermined angle. [Claim 4] Claim 2, characterized in that the amount of chamfering on the inner circumferential side and the outer circumferential side is approximately two-thirds of the wall thickness of the pipe.
Or the diamond core drill described in 3. 5. The diamond core drill according to claim 4, wherein the chamfer angles on the inner circumferential side and the inner circumferential side are approximately 25 to 45 degrees.