JPH09155617A - Cutting process of fiber type organic material, rigid and brittle inorganic material, and glass type inorganic material, by end mill shpaed tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cutting process a fiber type organic material, a rigid and brittle inorganic material, and a glass type inorganic material at a good processing surface accuracy and efficiently, by installing an end mill form tool to an axle held by a pneumatic static pressure bearing in the condition floating to a housing, and rotating the axle at a high speed. SOLUTION: In a pneumatic static pressure spindle 13, a very high speed rotating axle 21 combining an AC motor 22 integral is held by a pneumatic static pressure thrust bearing 23 and a radial bearing 24 in a housing 20, and a tool 14 is held to the front end of the axle 21 by a tool holder 25 such as a collet chuck. The pneumatic static pressure spindle 13 is rotated at a high speed, and a fiber type organic material, a rigid and brittle inorganic material such as a ceramics, and a glass type inorganic material are cutting processed accurately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting process using an end mill-like tool applicable to cutting fibrous organic materials such as wood materials and building composite materials, hard brittle inorganic materials such as ceramics, and glassy inorganic materials. Concerning the law.

[0002]

2. Description of the Related Art
A cutting machine (router) equipped with a main shaft of a rolling bearing has been used for cutting fibrous organic materials such as wood, but this causes large vibrations due to poor rotation accuracy and shortens tool life. In addition, since the machined surface roughness is large and the peeling is large, a lot of time is required for the post-process by hand finishing.
In addition, although hard brittle inorganic materials such as ceramics and glassy inorganic materials are ground using a grindstone, the actual situation is that an effective high-efficiency cutting method has not been established.

The present invention is intended to solve the above-mentioned problems. An end mill-like tool utilizing an aerostatic bearing is used to efficiently and efficiently process fibrous organic materials, hard brittle inorganic materials, and glassy inorganic materials. It is intended for cutting.

[0004]

SUMMARY OF THE INVENTION The present invention provides an aerostatic bearing and an end mill-like tool at 30,000 to 50,000 rpm.
At high speed, to process fibrous organic materials without post-finishing of hand-finished materials, and to hard and brittle inorganic materials such as ceramics and vitreous inorganic materials with the same machined surface precision and efficiency. Characterize.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram of a cutting apparatus used in the present invention, and FIG. 2 is a diagram showing the structure of an aerostatic spindle. Ultra high speed cutting machine 1 is CN
It is composed of a triaxial slide mechanism (Z-axis slide 12, X-axis slide 15, Y-axis slide 16) controlled by the C device 11. The Z-axis slide 12 is a slide that moves up and down with respect to a workpiece 14, to which an aerostatic spindle 13 holding an end mill-shaped tool 14 is attached.
The workpiece 17 set on the table 18 is cut. Of course, a table structure having three or more axes of movement may be used. In the aerostatic spindle 13, as shown in FIG. 2, an ultra-high speed rotary spindle 21 in which an AC motor 22 is integrally coupled in a housing 20 is supported by an aerostatic thrust bearing 23 and a radial bearing 24. 22
Can drive at a maximum of 100,000 rpm, and the tool 14 is held at the tip of the main shaft by a tool holder 25 such as a collet chuck. Thrust bearing 23, radial bearing 24
The air pressure of about 6 kg / cm ² is constantly supplied to and exhausted from the space of about 1/100 mm, so that the motor 22 and the main shaft 21 are supported in the housing 20 in a completely floating state. Such an aerostatic spindle has low frictional resistance, has low power consumption and excellent high-speed rotation, and has a high dynamic rigidity because it is constrained by air pressure, and has sufficient resistance to cutting hard materials. It absorbs the impact force of cutting and obtains high rotation accuracy (runout accuracy 0.5 μm). Since the rotational accuracy is high as described above, no vibrating force acts on the cutting edge, so that the tool life can be extremely extended and the accuracy of the machined surface is significantly improved.
As the main shaft material, invar or the like, which is a low thermal expansion material, is used to suppress deformation due to heat generation, and a material having high solid lubricity is used to prevent seizure on the inner surface of the housing.

The end mill-like tool used in the present invention prevents the tool life from decreasing and improves the accuracy of the machined surface, so that the tool runout (eccentricity from the spindle rotation center) is suppressed within 5 μm, and the tool material In the case of soft materials such as fibrous organic materials, cemented carbide, cubic boron nitride,
Diamond or the like is used, and in the case of a hard brittle inorganic material such as ceramics or a glassy inorganic material, diamond is used.

By the way, the cutting resistance of the end mill-like tool increases sharply with the increase of the cutting depth in the axial direction (depth direction), and is relatively insensitive to the single blade feed amount (Sz). The single blade feed amount Sz is expressed by the following equation. Sz = F / SN (mm / blade) F: Cutting feed speed (mm / min) of end mill-shaped tool S: Rotational speed (rpm) of end mill-shaped tool N: Number of flutes of end mill-shaped tool Therefore, increase cutting efficiency For this purpose, it is possible to suppress the axial cutting and increase the feed amount by one blade.

In the case of soft materials such as fibrous organic materials such as wood materials, building composite materials, composite materials, plastics and fiber reinforced plastics, the cutting feed rate should be increased while rotating as fast as possible. Single blade feed amount S
It is desirable to cut at z of 0.1 mm / min or more.

Further, in the case of a hard brittle inorganic material such as ceramics or a glassy inorganic material, it is necessary to rotate at a high speed to reduce the cutting feed rate so that the single blade feed amount Sz is 3 μm or less.

Even if the cutting feed speed (F) is increased in this way, the single blade feed amount Sz can be maintained at a predetermined value by increasing the rotation speed S, and by the control of the CNC device of FIG. For example, in the case of a soft material, high-efficiency cutting feed enables high-efficiency cutting so as not to cause deformation of a shape, overheating of a tool, or overload.

In any of the work materials, if the peripheral speed (cutting speed) of the tool is too high, the temperature of the tool rises, and if it is too slow, the work material adheres to the cutting edge and the cutting ability decreases. There's a problem. The peripheral speed V of the tool is expressed by the following equation.

V = 2πrS / 1000 (m / min) r: maximum radius (mm) from the center axis of the tool to the work material (see FIG. 3, but in the case of a square end mill, r =
R) Therefore, it is necessary to appropriately set the rotation speed S according to the tool diameter and the hardness of the work material.

[0013]

[Example] Wood is used as a work material, a carbide ball end mill φ2 is used as a processing tool, and a tool rotation speed is 50000 rp.
m, axial cut 0.5 mm, radial cut 0.5
It was possible to obtain a good machined surface by carrying out the cutting process at a feed rate of 1 mm and a feed rate of 10000 mm / min.

[0014]

As described above, according to the present invention, there is no need for a post-finishing step for hand-finishing, which has been conventionally required for cutting a fibrous organic material, to obtain a machined surface accuracy, and ceramics or the like. The hard and brittle inorganic material and the glassy inorganic material can be efficiently and efficiently machined without using a grindstone, and moreover, it can be machined with an electric power that is less than an order of magnitude less than that when a bearing is used. Become.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of an ultra-high speed cutting machine used in the present invention.

FIG. 2 is a diagram showing the structure of an aerostatic spindle.

FIG. 3 is a diagram illustrating an end mill-shaped tool.

[Explanation of symbols]

1 ... Ultra-high speed cutting machine, 11 ... CNC machine, 12 ... Z
Axle slide, 13 ... Aerostatic spindle, 14 ... Tool,
15 ... X-axis slide, 16 ... Y-axis slide, 17 ... Workpiece, 18 ... Table, 20 ... Housing, 21 ... Spindle,
22 ... Motor, 23 ... Thrust bearing, 24 ... Radial bearing, 25 ... Tool holder.

Claims (7)

[Claims] 1. An end mill shape characterized by attaching an end mill-like tool to a main spindle held in a floating state by an aerostatic bearing and rotating the main spindle at a high speed to cut a fibrous organic material. Cutting method for fibrous organic materials with tools. 2. The cutting method according to claim 1, wherein the fibrous organic material is a wood material, a composite material for construction, a composite material, plastics, or a fiber reinforced plastics. 3. An end mill-like tool, characterized in that an end mill-like tool is attached to a spindle held in a floating state with respect to a housing by an aerostatic bearing, and the spindle is rotated at a high speed to cut a hard brittle inorganic material. Cutting method for hard and brittle inorganic materials with tools. 4. An end mill shape characterized in that an end mill-like tool is attached to a main spindle held in a floating state with respect to a housing by an aerostatic bearing, and the main spindle is rotated at a high speed to cut a glassy inorganic material. Cutting method for glassy inorganic materials with tools. 5. The rotation speed of the spindle is 30,000 to 5,000.
The cutting method according to any one of claims 1 to 4, wherein the cutting method is 0 rpm. 6. The cutting method according to claim 1, wherein the runout accuracy of the spindle is within 0.5 μm. 7. The amount of deflection of the end mill-shaped tool with respect to the center of rotation of the spindle is 5 μm or less.
4. The cutting method according to any one of 4 to 4.