JPH08325758A - Device and method for processing curved surface - Google Patents

Abstract

PURPOSE: To finish the curved surface of a surface to be processed without the occurrence of flaws and distortions by directing a processing head facing the work having a curved surface shape perpendicularly toward the surface to be processed and subjecting the surface to plasma etching while changing the relative positions. CONSTITUTION: The work 1 having the curved surface shape is placed on a rotary table 2 within a reaction vessel 7 and a reactive gas contg. active particles formed in a plasma forming chamber 4 is supplied from the processing head 3 facing the work to the work, by which the plasma etching of the work 1 is executed. At this time, the processing head 3 is directed perpendicularly to the surface to be processed and is moved in this state relatively while the work 1 is kept rotated. The control of the processing head 3 is executed by two-dimensionally or three-dimensionally changing the relative positions of the processing head 3 via a moving and oscillating device 5 having a controller 8 and oscillating the head, thereby directing the head perpendicularly to the surface to be worked. As a result, the reactive gas formed as plasma is made to flow in the tangent direction of the surface to be processed of the curved surface shape of the work, by which the surface to be processed is finished to the desired shape accuracy and surface roughness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for forming a surface of a curved surface such as a lens having a spherical surface or an aspherical surface, a metal mold, or the like.

[0002]

2. Description of the Related Art Conventionally, curved surface creation has been performed by mechanical processing such as cutting, grinding and polishing, and removal processing by electrical processing such as electrical discharge machining. On the other hand, in chemical removal processing such as plasma etching, a chemical reaction occurs between the active particles in the reaction gas and the workpiece on the surface of the workpiece,
Since the reaction products are removed, the machined surface is not damaged. Further, regarding the improvement of the spatial controllability, which has been a problem in the processing using plasma, Japanese Patent Laid-Open No. 125
829 and 43rd Annual Symposium on Frequency Control: 623, published by The Institute of Electrical Communication (1989).

[0003]

[Problems to be Solved by the Invention]
Mechanical removal processing such as grinding and polishing deforms and destroys the work piece due to the physical action that occurs between the cutting tool or the abrasive and the work piece, resulting in crystal fracture and residual strain on the work surface.

In electric discharge machining, the work is melted and removed by the heat of the electric spark, so that a heat deformable layer or the like is formed on the machined surface. Therefore, these processes change the physical properties of the processed surface, and generally deteriorate the material properties.

Also in the case of plasma etching, radiant heat at the time of plasma generation and high-speed charged particles may affect the processed surface. It is an object of the present invention to provide an apparatus and method for finishing a work surface having a two-dimensional or three-dimensional curved surface that does not cause work strain or damage due to work.

[0006]

The curved surface processing apparatus of the present invention is a processing apparatus utilizing plasma etching,
A machining head facing a curved workpiece, a plasma generation chamber for supplying a reactive gas containing active particles to the machining head, a table on which the workpiece is mounted, the workpiece and the machining head. A moving / oscillating device having a two- or three-dimensional moving mechanism for changing the relative position and an oscillating mechanism for orienting the machining head perpendicularly to the surface of the workpiece to be machined, and a control for controlling this moving / oscillating device It comprises an apparatus and a reaction container which houses at least the processing head and a workpiece.

Further, the curved surface processing method is a method in which a processing head for flowing a reaction gas containing active particles is directed perpendicularly to a surface to be processed in a reaction vessel in the reaction vessel. It is characterized in that it is moved along the processing curved surface and the processing utilizing plasma etching is performed.

[0008]

With the above-described structure, the reaction gas which is made into a plasma is flowed in the tangential direction of the surface of the processing target portion having the two-dimensional or three-dimensional curved surface shape. This makes it possible to obtain a flow of the reaction gas suitable for improving the shape accuracy and surface roughness of the workpiece.

Further, since processing is performed by a chemical action, processing strain and damage to the processed surface can be minimized. Further, since the gas after the reaction is quickly exhausted from the portion to be processed by the gas flow between the processing head and the object to be processed, it is possible to prevent the processed surface from being contaminated by the reaction product.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall configuration diagram showing an embodiment of the present invention. In FIG. 1, 1 is a work piece, 2 is a rotary table as a table on which the work piece 1 is mounted, 3 is a processing head for supplying a reaction gas to the work piece 1, 4 is plasma, and a reaction is performed. Plasma generation chamber for supplying gas, 4
Reference numeral 1 is a connecting pipe connecting the processing head 3 and the plasma generation chamber 4, 5 is a moving / swinging device for changing the relative position between the workpiece 1 and the processing head 3, 7 is a reaction container, and 71 is an exhaust port. .

Next, a method of processing an axisymmetric curved surface with the above configuration will be described. First, the rotary table 2 is rotated, and the processing head 3 is moved / swinged by the moving / swinging device 5.
Move along a desired axisymmetric curved surface.

FIG. 2 shows the positional relationship between the workpiece 1 and the machining head 3 during this movement. In the figure, I is the central axis of the rotary table 2, point A is the intersection of the workpiece mounting surface of the rotary table 2 and the I axis, point B is one point on the machined surface, and straight line II is the normal to the machined surface at point B. Represents At this time, the processed surface shape can be defined by the distance x from the I axis of the point B, the distance z from the upper surface of the turntable, and the angle θ formed by the axes I and II.

On the other hand, the workpiece 1 is installed so that its axis of symmetry coincides with the axis I, and the moving / swinging device 5 moves and swings the working head 3 in a plane including the axis I. Set. Here, the controller 8 controls the moving / swinging device 5 so that the machining head 3 is in the position / orientation determined by the above (x, z, θ), and the workpiece 1 is rotated to a desired position. The processing head 3 can be moved along the axisymmetric curved surface.

Next, during the movement of the processing head 3, the reaction gas containing active particles generated in the plasma generation chamber 4 is caused to flow out from the processing head 3. At this time, the reaction gas flows through the gap between the workpiece 1 and the machining head 3 in the tangential direction of the surface of the workpiece, and the machining is performed in this gap.

With the curved surface processing apparatus based on the above configuration and method, the reaction gas becomes a uniform radial flow parallel to the surface to be processed, which is suitable for curved surface creation. Therefore, the shape accuracy and surface roughness of the workpiece can be improved. Further, since the processing progresses by a chemical action, there is no damage on the processed surface or residual processing strain, and no deterioration of material properties occurs. Further, as the reaction product gas flows, it is quickly exhausted from the processing progress portion between the workpiece 1 and the processing head 3, so that contamination and uneven processing due to the reaction product can be prevented, and at the same time, the processing efficiency can be improved. You can

In FIG. 1, the plasma generation chamber 5 is arranged outside the reaction container 7, but this is not shown.
It may be placed inside. Further, as shown in FIG. 2, the relative position / posture between the workpiece 1 and the processing head 3 needs to be controlled at least three axes including one axis of swing.

In FIG. 1, a moving / oscillating device is used which causes all of the three axes of movement / oscillation to act on the machining head 3. However, some of the control axes act on the workpiece 1. You may Further, the number of axes may be four or more in order to enhance the effect of relative movement.

In the above embodiment, an example of processing a rotationally symmetrical curved surface having an axis of symmetry has been described. However, the present invention can be applied to processing of any two-dimensional or three-dimensional curved surface, and the movement of the workpiece 1 and the processing head 3 can be performed. The swinging device 5 can also be variously changed, for example, by mounting the workpiece 1 on a table that moves the workpiece 1 in X, Y, and Z, and moving the processing head 3 only by swinging.

Next, FIGS. 3 to 5 show various tip shapes of the processing head 3. Here, the processing head 3
Is preferably cylindrical with the reaction gas outflow path 31 as the center. Further, the size of the tip needs to be limited within a range in which the curvature of the processed surface is considered to be constant.

FIG. 3 shows an example in which the surface perpendicular to the outflow direction of the reaction gas has a tip shape. This is a type in which the processing head has a simple shape and is easy to manufacture, and is suitable when the processing surface is spherical or when the processing surface has a relatively small curvature.

FIG. 4 is an example in which the tip shape is concave with respect to FIG. This is suitable for a curved surface having a positive curvature, such as processing of a convex lens. Further, in the case of processing a curved surface shape, it is possible to widen the range of curvature that can be processed by setting the angle of the recess according to the magnitude of the curvature.

FIG. 5 shows an example in which the tip shape is convex with respect to FIG. This is suitable for a curved surface having a negative curvature such as a concave lens processing or a curved surface having a large curvature change in processing an aspherical lens. Also, FIG.
Similar to the above, by setting the angle of the convex portion, it is possible to widen the range of curvature that can be processed. 4 and 5, the tip shape is illustrated assuming that it is a conical surface, but it is also possible to give a curvature according to the shape of the processed surface.

[0023]

The reaction gas suitable for improving the shape accuracy and the surface roughness of the workpiece is made to flow by flowing the reaction gas that has been turned into plasma in the tangential direction of the surface of the processing target portion having the two-dimensional or three-dimensional curved surface shape. You can get the flow.

Further, since processing is performed by a chemical action, processing strain and damage to the processed surface can be minimized. Further, since the gas after the reaction is quickly exhausted from the processing target portion by the gas flow between the processing head and the workpiece, it is possible to prevent contamination of the processed surface by the reaction product.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an overall configuration of an embodiment of a processing apparatus of the present invention.

FIG. 2 is an explanatory diagram of a relative position between a workpiece and a processing head.

FIG. 3 is a vertical sectional view of a processing head.

FIG. 4 is a vertical sectional view of a processing head.

FIG. 5 is a vertical cross-sectional view of a processing head.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Workpiece, 2 ... Table, 3 ... Processing head, 4 ... Plasma generation chamber, 5 ... Moving / oscillating device, 7 ... Reaction container, 8
…Control device.

Claims (2)

[Claims] 1. In a processing apparatus using plasma etching, a processing head facing a curved workpiece, a plasma generating chamber for supplying a reactive gas containing active particles to the processing head, and the workpiece are provided. Moving / swinging having a table to be mounted, a two- or three-dimensional moving mechanism for changing the relative positions of the workpiece and the processing head, and a swinging mechanism for orienting the processing head perpendicularly to the workpiece surface of the workpiece. A curved surface processing device comprising a moving device, a control device for controlling the moving / swinging device, and a reaction container accommodating at least the processing head and a workpiece. 2. In a reaction vessel, along a processing curved surface of a workpiece with a processing head for flowing out a reaction gas containing active particles perpendicular to the processing surface with respect to a curved workpiece. The curved surface processing method is characterized in that the surface is moved and moved to perform processing using plasma etching.