JPH01171712A - Machine method and machining drill for fine hole - Google Patents

Abstract

PURPOSE:To enable cutting at the maximum cutting speed even with a fine diameter or with a hard cutting material by pushing a twist drill which has the specific ratio of cutting-edge diameter to length and in which a super adrasive grain powder with a specific mesh is fixed to the peripheral face of a cutting edge with a specific diameter, against a workpiece and rotating it for specific number of times. CONSTITUTION:A twist drill having the ratio of cutting-edge diameter to length at 1:1.6-1:13 and in which a super abrasive grain of 20-1000mesh is fixed to the peripheral face of a cutting edge 2 with a diameter below 3.0mm, is pressed against a workpiece and rotated at above 12000R/M. Since the twist drill 3 is thus formed by fixing the powder of a super adrasive grain 8 on the peripheral face of the cutting edge 2, at the time of carrying out the machining of a fine hole by pressingly rotating the drill 3 against a workpiece of a ceramic, etc., the discharge of chips and the circulation of a coolant are favorably carried out while chemically fixing the abrasive grains and a plated layer onto the uneven face of the drill. Hence, the abrasive grains can be fixed more firmly as compared to the conventional case in which merely a diamond powder is chemically bonded to a cylindrical base metal, thereby, enabling the abrasive grains to stand a higher cutting resistance, to enable the drill to carry out highly efficient machining.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention aims to provide a method for forming microholes in ceramics, plastics, metals, etc., and a drill used for forming microholes. .

<Conventional techniques and their problems> Conventionally, in order to machine micro holes of 0.3 to 3.0 mm diameter in difficult-to-cut materials such as ceramics, plastics, and metals, ultrasonic machining using free abrasive grains, electrical discharge machining, Special processing methods such as laser processing and internal electrodeposition methods have been used.

However, the former special processing method has problems in that it is difficult to control roundness and the hole diameter in the depth direction, and the processing speed is slow. In addition, in the latter processing method, because the diamond powder is fixed to the outer periphery of the cylindrical alloy, it is not possible to remove chips or lubricate the coolant sufficiently, so the diamond powder falls off before it reaches its full potential. There was a problem that the tool life was short.

In addition, 0.3 to 3.0. Vib-shaped core drills in the #Iφ range are expensive to manufacture and have low tool rigidity, so they have been considered unsuitable for machining difficult-to-cut materials.

Means for Solving the Problems> The present invention was obtained as a result of studies to solve the problems of the conventional microhole processing described above.

That is, the present invention provides a microhole processing method characterized by pressing a twist drill in which superabrasive powder is implanted on the circumferential surface of the cutting edge against a workpiece and rotating it, and a method for machining microholes, which is characterized by changing the diameter and length of the cutting edge of the twist drill. The present invention provides a micro-hole drilling drill in which the ratio is 1:1.6 to 1:13 and superabrasive powder is implanted on the circumferential surface of the cutting blade.

<Operation> The first feature of the drill A of the present invention is that the shape of the alloy is a twist drill type with a spiral groove 1 formed on the cylindrical outer periphery, as shown in FIG.

The second feature of this twist drill A is that superabrasive powder is implanted and fixed onto the two circumferential surfaces of the cutting blade by electrodeposition.

In this way, superabrasive powder is implanted and fixed on the circumferential surface of the cutting edge to create a tightened twist drill, so when this drill is pressed against a workpiece such as ceramics and rotated to machine a microscopic hole, chips are generated. Because the abrasive grains and plating layer are chemically bonded to the uneven surface of the drill, the diamond powder is chemically bonded to the cylindrical base metal. In comparison, the abrasive grains are firmly fixed, which allows the abrasive grains to withstand higher cutting paper fragments, allowing for high-efficiency machining.

In the present invention, it is preferable to use high speed steel or cemented carbide as the base metal of the twist drill in place of conventional piano wire in order to increase its rigidity.

In addition, as a superabrasive powder that is implanted and fixed by electrodeposition etc. on the circumferential surface of the cutting edge with a helical groove of a twist drill, 2
Diamond powder or cubic boron nitride powder with a mesh size of 0 to 1000 is preferably used.

The twist drill according to the present invention preferably has a cutting edge diameter to length ratio of 1:1.6 to 1:13, and the number of revolutions when pressing against a workpiece to machine a microhole is 12,000 R.
PI (preferably.

<Example> Next, the present invention will be explained in detail with reference to Examples.

First, we used cemented carbide as a material and made the entire length as shown in Figure 2.
A helical groove 1 is formed in the drill body 3 with the outer diameter φD of the tip of the cutting blade.
Base metal B was prepared by processing.

Next, an insulating coating film 5 was formed on the shank portion 4 of this base metal 8 as shown in FIG.

After that, in order to clean and activate the surface of the drill body part 3 of this base metal B, the surface is subjected to a pretreatment of electric commentary → water washing → pickling → water washing, and then a base layer is applied to the surface of this drill body part with a thickness of 2 A base nickel plating of ~5 μm was applied.

The drill body of the base metal B thus treated is immersed in a jig 7 containing abrasive grains 8 in a plating tank 6 containing a nickel plating solution 9 as shown in FIG. B is a cathode,
Nickel plating was performed under predetermined conditions using the NL plate 10 in the plating bath 6 as an anode, and the abrasive grains 8 in the jig 7 were fixed by electrodeposition on the surface of the drill body.

Next, after fixing the abrasive grains, the base metal 8 is transferred to another plating plate 11 filled with nickel plating solution 9 as shown in FIG. Nickel plating was applied until it became .

Thereafter, the base metal 8 was taken out from the plating bath, and the insulating coating film 5 on the surface of the shank portion 4 was removed with a solvent such as acetone or thinner, thereby obtaining a drill of the present invention.

Using the drill of the present invention and the conventional drill shown in Table 1 obtained in this way, the zirconia ceramic work material was
~2. When we tried drilling Omrnφ microholes, we found that the drill of this invention significantly exceeded conventional products in both performance and lifespan.

Especially in the drill of this invention, the rotational speed is so, oo.

Very good results were observed with rlPH.

Table 1 Note that in the above examples, the superabrasive powder was fixed to the entire circumference of the drill body, that is, the cutting edge, but the superabrasive powder was not applied to the grooves and other parts that are not directly involved in grinding. There is no problem.

<Effects of the Invention> As explained above, the drill of the present invention is of a twist type, and by implanting and fixing superabrasive powder into the drill body, it is possible to grind even small diameter holes when making micro holes in a workpiece. Furthermore, the maximum cutting speed can be set high even for difficult-to-cut materials, and productivity can be improved two to three times with high efficiency compared to conventional products.

Furthermore, the life of each tool can be increased by 3 to 8 times, and the machining quality can be further improved.

[Brief explanation of the drawing]

FIG. 1 is a side view of the drill of the present invention, and FIGS. 2 to 5 are explanatory diagrams showing one example of the manufacturing process of the drill of the present invention.

Claims (5)

[Claims] (1) A microhole machining method characterized by pressing a twist drill with superabrasive powder implanted on the circumferential surface of the cutting edge against a workpiece and rotating it. (2) The processing method according to claim 1, wherein the twist drill has a cutting edge diameter of 3.0 m/m or less and a rotation speed of 12,000 RPM or more. (3) The cutting edge diameter and length ratio of the twist drill is 1:1.6
1 to 1:13, and is characterized in that superabrasive powder is implanted on the entire circumferential surface of the cutting blade. (4) The drill for microhole drilling according to claim 3, wherein the superabrasive powder is diamond powder or CBN with a size of 20 to 1000 mesh. (5) The micro-hole drilling drill according to claim 3 or 4, wherein the superabrasive powder is implanted by electrodeposition on the circumferential surface of a twist drill base made of cemented carbide or high speed steel. .