JPS6171901A - Method of cutting plastic - Google Patents

Abstract

PURPOSE:To highly accurately process a mirror surface of a plastic lens, etc., by blowing compressed air including an ion to a position of processing to remove static electricity produced in the processing, and attracting cut powder. CONSTITUTION:A plastic workpiece 2 is mounted on a main shaft 3, and driven for rotation for performing prescribed processing for a mirror surface by means of a cutting tool 1. Compressed air including an ion is blown to a position of processing from a charge removal device gun 14. The gun 14 has an ion generating part, and hence static electricity produced between the workpiece 2 and the cutting tool 1 is removed by means of the ion-containing compressed air. The cut powder is removed via an attraction duct 12. Accordingly, the machine tool is prevented from being erroneously operated for assuring precession mirror surface cutting.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a plastic cutting method for mirror-finishing high-precision products such as plastic lenses using a machine tool, and in particular, to prevent static electricity generated during processing and to achieve high-precision processing. The present invention relates to a one-man cutting method for plastics that is suitable for enabling the invention and preventing machine malfunctions.

[Background of the invention]

When processing plastic lenses and the like using machine tools equipped with ultra-precise numerical control mechanisms, runaway accidents may occur during processing. The reason for this is that when plastic is cut with a diamond cutter, static electricity is generated because both are insulators, and sparks fly to the diamond cutter, which affects the numerical control mechanism. In addition, the static electricity causes the chips to become entangled between the tool and the workpiece, and also to adhere to the rake face of tool 1, which rubs against the machined surface, making the machined surface rough and making it difficult to perform high-precision mirror finishing. A problem will occur.

In the prior art, various methods for removing static electricity as described in 1 have been adopted. One such method is to make a mist of water, vegetable oil, Freon, etc., and spray it onto the workpiece to reduce the air humidity around the workpiece to about 45% or more. However, this method not only requires cleaning after processing, but also has drawbacks such as dimensional changes due to the moisture absorption of the plastic and expansion when Freon evaporates, and rust on the machine tool. there were. Furthermore, even if the humidity of the atmosphere was increased as described above, the generation of static electricity could not be completely prevented.

Other conventional techniques have also found it difficult to completely prevent static electricity. [Objective of the Invention] The present invention is intended to solve the above-mentioned drawbacks, etc. The purpose of the present invention is to prevent the generation of static electricity and malfunction of machine tools, and to prevent workpieces from being damaged. Plane 2
The object of the present invention is to provide a plastic cutting method capable of high-precision mirror cutting into various shapes such as spherical and aspherical surfaces.

[Summary of the invention]

In order to achieve the above object, the present invention sprays compressed air containing ions near the machining location of a workpiece to remove static electricity, and, for example, disposes a suction duct at the machining location to remove chips. , is characterized by a plastic cutting method that performs mirror cutting while preventing chips from adhering to the workpiece and the cutting tool.

[Embodiments of the invention]

Embodiments of the present invention will be described below based on the drawings.

First, an overview of this embodiment will be explained.

As shown in FIG. 1, a workpiece 2 gripped by a chuck 11 of a main spindle 3 is mirror-finished by pies 1 to 1 (such as diamond pies 1 to 1) fixed on a tool post 10.

A static eliminator gun 14 for spraying compressed air containing ions and a suction duct 12 for absorbing generated chips are disposed near the cutting edges of the pies 1 to 1-.

From the above, it has been confirmed that by preventing the generation of static electricity between the workpiece 2 and the pies 1 to 1 and sucking chips, malfunction of the machine tool is prevented and highly accurate mirror finishing is performed.

This example will be explained in more detail below.

Figure 4 shows the general structure of a machine tool that performs mirror cutting.

Two tables 6 are supported on the bed 7 so as to be slidable in two directions, and an X-cheaple 5 is supported so as to be slidable in the X direction. The X table 5 has a feed screw 9 connected to the motor 8.
The Z table 6 is moved by the motor 16 and a feed screw (not shown). A main shaft 3 that rotatably supports a workpiece 2 is placed on the second table 6 and is rotated by a main shaft motor 4. Further, a tool rest 10 is fixed on the X table 5, and a cutting tool 1 is movably held and fixed on the tool rest 10.

This embodiment is applied to a general-purpose machine tool having the above structure, and is also effectively applied to an ultra-precision NC lathe having a numerical control mechanism (not shown). The workpiece 2 and the cutting tool 1 are moved to desired positions by numerical control, and desired mirror cutting is performed.

As shown in FIG. 1, the workpiece 2 is gripped by a chuck 11 installed on the spindle 3.

The cutting tool 1 is made of a highly hard metal material such as diamond, and is fixedly held on the tool rest 10 so that no cracking occurs.

A static eliminator gun 14 is disposed near the lower side of the rake face of the cutting tool 1, and the static eliminator gun 14 is held on a fixed base 15 fixed to the tool rest 10. In addition, a suction duct 12 is provided near one side of the rake surface of the cutting tool.
is held on a fixed base 13 fixed to the tool rest 10.

As shown in FIG. 2, the static eliminator gun 14 has an air hole 14a that blows out compressed air from an air pipe 14d, and an air hole 14a that blows out compressed air from an air pipe 14d.
It is formed of an ion generating section 14b which is disposed surrounding the ion generating section 14b and generates positive and negative surface ions by performing alternating current corona discharge, and a power supply section 1.4c connected to the ion generating section 14b.

For example, compressed air of 0.8 kg/rdG is used.

Next, the operation of this embodiment will be explained.

The workpiece 2 is rotationally driven by the main shaft 3 as described above. 2
The table 6 and the X-table 5 are moved, the workpiece 2 and the cutting tool 1 are positioned at a predetermined position, and a predetermined mirror cutting process is performed. Of course, the workpiece 2. is controlled by a numerical control mechanism (not shown).
The cutting tool 1 is moved in the X, Y (perpendicular to the X, , and Z directions) and Z directions to perform processing into a desired shape.

During the cutting process, compressed air containing ions is blown from the static eliminator gun 14 to the cutting position.

At the same time, the suction duct 12 is driven to suck the generated chips.

As a result of this, the static electricity generated between the workpiece 2 made of plastic material and the cutting tool 1 is removed, and chips are not entangled with the cutting tool 1 and the workpiece 2, and chips do not adhere to the rake face of the cutting tool 1. This makes it possible to obtain a good mirror surface. By the way, in the conventional technology, static electricity of 2V was generated, but according to this embodiment, it is less than 20V,
The control device does not malfunction and is rarely a problem. Also, the surface roughness is 0. O5BmT-<7 to 0.015
It is demonstrated that μmR2.

Figure 2 shows a modified example of the usage state.
2 is omitted +n3. A static eliminator gun 14 is disposed below the rake face of the cutting tool 1. Static eliminator gun 14
This modification is sufficient if the chips are sufficiently scattered by the compressed air.

FIG. 3 shows another modification of the embodiment shown in FIG. 1, in which another static eliminator gun 14' is added. The static eliminator gun 14' is disposed on one side of the rake face of the pies 1-1. With this configuration, the amount of ions generated by one static eliminator gun 14.14' can be reduced, the structure of the static eliminator gun 14.14' can be simplified, and the dispersion of ions can be made uniform to eliminate static electricity. The effect can be further improved.

Although not shown, the quantity and installation location of the static eliminator gun 14 and the suction duct 1-12 are not limited.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, it is possible to prevent malfunctions of machine tools and to perform high-precision mirror cutting of workpieces into various shapes.

[Brief explanation of drawings]

FIG. 1 is a side view showing one embodiment of the present invention, FIGS. 2 and 3 are perspective views showing variations in use of the present invention, and FIG. 4 is a general workpiece to which the present invention is applied. It is a perspective view showing a machine. 1...Bite, 2...Workpiece, 3...Spindle, 4...
...Spindle motor, 5...X table, 6...Z table, 7...bed, 8...motor, 9...feed screw, 10...turret, 11...chuck , 12・
...Suction duct, 13.15...Fixing stand, 1.4.1
4'... Static eliminator gun, 14a... Air hole, 14b.
...Ion generation section, 1.4c...Power supply section, 14d...
・Air pipe, 16...motor. Representative Patent Attorney Tadashi Akimoto Figure 2 Figure 4

Claims (1)

[Claims] 1. In a cutting method for mirror-finishing plastic using a cutting tool, static electricity generated during processing is removed by blowing compressed air containing ions onto the processing area, and while removing generated chips. A plastic cutting method characterized by processing. 2. The first aspect of the present invention is characterized in that the mirror-finishing process involves mirror-cutting the workpiece into flat, spherical, and aspherical shapes using a high-hardness metal tool such as diamond.
Plastic cutting method described in section. 3. A static eliminator gun that generates positive and negative ions by corona discharge and blows them out together with compressed air is provided near the cutting tool, and a suction duct that sucks the generated chips is provided to perform the mirror finishing. A plastic cutting method according to claim 1. 4. The plastic cutting method according to claim 1, wherein the mirror finishing of the plastic is performed by a machine tool having a numerical control mechanism.