JPH0241844A - Non-spherical working machine - Google Patents

Abstract

PURPOSE:To perform a non-spherical working of super precision by processing by operating the work point abutting to the work face of an edge tipe based on the input data in the work face shape of a work and the edge tip shape of a cutter and eliminating the error caused on the edge tip shape by controlling with corrected NC work data. CONSTITUTION:In the data processing mechanism 50 of a non-spherical work machine controlled by orthogonal two shafts, an edge tip shape measuring means 60, its memory means 53 and a work face shape input means 56, its memory means 54 are attached. Moreover, a work point calculating means calculating the work point abutting to the work face of the edge tip on each position of the work face from this stored edge tip shape and work face shape and the correction means of NC work data are provided. By this structure, the work point of the edge tip is operated based on the measured edge tip shape and the work face shape to be worked and the NC work data added with correction according to the work point thereof is prepared.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Utilization" The present invention relates to an aspherical surface processing machine for creating molds for aspherical surfaces such as plastic lenses.

``Conventional technology J'' To process such curved surfaces, NC machining is performed by face turning using an ultra-precision lathe.
There were two types of machines that simultaneously controlled two orthogonal axes for machining, and others that added a rotation axis to the two orthogonal axes and controlled three axes at the same time. FIG. 6 shows a machine that performs machining by simultaneous two-axis control.
3, and is driven by a Z-axis motor 84. The main shaft 83 is rotationally driven by a main shaft motor 85, and a workpiece W is attached to the front surface of the main shaft 83. X
The shaft table 86 is movable in a direction perpendicular to the rotational axis of the main shaft 83 and is driven by an X-axis motor 87. X
A tool rest 88 is provided on the shaft table 86.
The workpiece W is face-turned by a diamond cutting tool 89 attached to the diamond cutting tool 8 to form, for example, a concave processing surface 90.

FIG. 7 shows an apparatus for machining using simultaneous three-axis control.

In this device, a B-axis table 91 is rotatably attached to the X-axis pull 86, and a tool rest 88 is provided on the B-axis table 91''. The B-axis table 91 is rotationally driven by the B-axis moke 92.

[Problem to be solved by the invention] However, in a device that simultaneously controls two orthogonal axes,
As shown in FIG. 8, the machining points 93 of the eight cutting tools move due to the inclination of the machining surface 90. Processing point 93
moves, and the actual n-element shape of 8 bites 9.1
There is always a problem that the ideal cutting edge shape 95 deviates from the top, which has a negative effect on the profile accuracy of the machined surface 90. teeth,
As shown in Fig. 9, the direction of the cutting tool 89 is constantly
Although the machining point 93 can be kept constant by controlling in the normal direction of 0, there is a problem that the addition of the rotation axis 91 complicates the machine configuration.

The present invention has been made to solve the above problems, and uses a simple machine configuration with only two orthogonal axes and no rotation axis to perform precise profile machining that is not affected by the shape of the cutting edge of the cutting tool. The purpose is to provide an aspheric surface machining machine that is capable of processing aspherical surfaces.

[Means for Solving the Problems] In order to achieve the above object, the present invention controls two orthogonal axes using a numerical control device (CNC device) to move the cutting tool relative to the workpiece, In an aspherical surface processing machine that turns a curved machined surface, there is provided a cutting edge shape measuring means for measuring the shape of the cutting edge of a cutting tool, a cutting edge shape memory means for storing the shape of the cutting edge, and a machined surface shape for inputting the shape of the machined surface of the workpiece. an input means, a machining surface shape memory means for memorizing the machining surface shape, and a machining point of the cutting edge of the cutting tool that comes into contact with the machining surface for each position on the machining surface based on the memorized cutting edge shape and machining surface shape. processing point calculation means for calculating N;
An aspherical surface processing machine is provided, comprising: NC processing data correction means for creating NC processing data in which a cutting tool edge shape is corrected based on the processing point for each movement position of the C processing data. Ru.

"Operation" In the aspherical surface machining machine configured as shown in L, the shape of the cutting edge of the cutting tool is measured before machining, and the data is taken into the cutting edge shape memory means.

Then, a machining point indicating which part of the cutting edge will be machined is calculated based on the measured shape of the cutting edge and the shape of the machining surface to be machined, and NC machining data is corrected according to the machining point. is generated. Therefore, by performing simultaneous two-axis control using the generated NC machining data, it is possible to eliminate the influence of the shape of the cutting edge of the cutting tool and precisely machine any aspherical surface.

“Example J Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view showing the configuration of an aspherical surface machining machine, which is basically configured as an ultra-precision lathe that is simultaneously controlled on two axes. This lathe is used to face-turn the workpiece and form curved surfaces such as lens surfaces.

The base 10 is made of marble that undergoes little thermal displacement.

A Z-axis support 11 is fixed to the marble base 10-H. The guide bar 12 provided on the support stand 11 has Z
A shaft table 13 is slidably guided and supported in the left-right direction (Z direction) in the drawing. The Zllll table 13 is screwed onto a feed screw 14A and is fed by a Z-axis motor 14. Z-axis table 13. A headstock 15 is fixed to H. The headstock 15 has a main shaft 1 in the axial direction parallel to the Z direction.
6 is rotatably supported and rotationally driven by a main shaft motor 17. A chuck 18 is provided at the tip of the main spindle 16 to be able to hold a workpiece W.

Furthermore, an X-axis support 21 is fixed on the marble base 10. A guide bar 22 is provided on the X-axis support base 21, and the X-axis table 23 is slidably guided in the front-rear direction (X direction) in the drawing.

The X-axis table 23 is screwed onto a feed screw 24A and is fed by the X-axis motor 24. A tool rest 25 is provided on the X-axis table 23. A cutting tool 26 such as a single-point diamond tool is fixed to this tool rest 25 so that a workpiece W held in front of the main shaft 16 can be face-turned.

Additionally, a laser length measurement system 30 is mounted on the marble base 10.
is installed to detect the displacement of the Z-axis table 13 and the X-axis table 23.

The laser beam is separated into the X direction and Z direction by the spectrometer 31, and passes through the pipes 32, 33 and the telescopic tubes 34.35, respectively, to the reflecting mirror 36.3 of each table 13.23F.
Sent to 7.

The Z-axis motor 14 and the X-axis motor 24 are connected to a CNC device 40 and are simultaneously controlled in two axes based on feedback signals from a laser length measurement system 30. CNC device 40
is a normal type equipped with a ROM in which a control program is stored, a RAM in which NC machining data, etc. are stored, a servo CPU that controls the Z-axis and X-axis motors, and a CPU that controls these.

The CNC device 40 is connected to an NC machining data processing device 50. The NC machining data processing device 50 is constituted by a minicomputer system, and includes a CPU 52 connected to the shape measuring device 260 via an interface 51, and a cutting edge that stores the cutting edge shape data from the shape measuring device W and 60. Shape memory 53. A machined surface shape memory 54 that stores the shape of the machined surface to be machined on the workpiece.
It has an NC machining data memory 55 that stores NC machining data for the CNC device 40. Machining surface shape input means 5
6, for example, by inputting coefficients of an aspheric polynomial representing the shape of the machined surface from the keyboard, or by inputting the coefficients of the CN
This is realized by receiving the NC machining data before correction from the C device 40.

FIG. 2 is a front view showing the external appearance of the shape measuring machine 60. A jig 62 is provided on a base 61, and a cutting tool 26, which is an object to be measured, is fixed to the jig 62 in an upright manner. A traverse unit 65 is provided on a support 63 that is provided upright on the base 61 so as to be movable up and down. From the traverse unit 65, a probe support 66 and a probe 67 are attached to the side.
is extended so that a stylus 68 provided at the tip of the probe can come into contact with the cutting edge of the cutting tool 26.

FIG. 3 is a front view showing the main parts of the traverse unit 65. The probe support 66 is supported by the traverse unit 65 so as to be able to swing around a pivot 70, and a prism 71 provided at the rear end reflects the laser light from the laser interferometric length measuring device 72, thereby supporting the probe. body 6
6 swing positions are detected. Further, the probe 67 is supported by the probe support 66 so as to be movable back and forth, and is driven by a servo motor 73 via a ball screw 74 . The advancing and retreating positions of the 10-branch 67 are detected by a spectroscopic laser length measurement system (not shown).

The data of the swinging position of the probe support 66 and the advance/retreat position of the probe 67 detected by the laser interferometric length measuring device 72 is processed by the data processing unit 69 of the shape measurement v160, and is composed of points of X-Y orthogonal coordinates. The data is sent to the NC machining data processing device 50 as blade edge shape data.

Based on the above configuration, the NC machining data processing device 50 creates an approximation formula for the shape of the cutting edge using spline approximation or the like from the cutting edge shape data made up of the dots. Then, as shown in FIG. 4, the machining points (Xm, Zw) where the cutting edge contacts the machining surface 90 are determined for each position on the machining surface based on the machining surface shape 90 stored as an approximate expression of the cutting edge shape. Calculate. Then, according to the machining point (Xw, Zi+), the top position of the cutting edge! (xヮ., 2) is calculated, and new NC machining data corrected by the calculated value is generated. By performing machining using this corrected NC machining data, the machining point (xv, z-) based on the shape of the cutting edge of the cutting tool 26 and the cutting edge apex position ( Controlled and accurate curved surfaces can be machined.

FIG. 5 is a flowchart showing the processing of the CPU 52 of the NC data processing device 50 that realizes the control concept described above. When the process 100 is started, step 10 is first performed.
In step 1, a cutting tool name R is input to the shape measuring device 60.

This is done by controlling the servo motor 73 of the traverse unit 65 according to the designation R, and adjusting the 10-
This is to move the block 67. In step 102,
The shape measuring device 60 measures the shape of the cutting edge of the cutting tool 26 and reads the shape data of the cutting edge. These data are sent to the NC machining data processing device 50.

In step 103, an approximation formula for approximating the shape of the cutting edge is created by spline approximation based on the cutting edge shape data. In step 104, coefficients of an aspherical polynomial representing the shape of the machined surface of the workpiece W are input. And step 1
In step 05, the machining point (xm, z), which is the contact point between the cutting tool tip and the workpiece processing surface, is calculated from the approximate expression of the cutting edge shape and the polynomial representing the processing surface shape, and in step 106, the apex of the cutting tool tip is calculated. The position (xm., Zmo) of is calculated. In step 107, the NC interpolates the corrected curve according to the machining point and the cutting edge apex position at that time.
Machining data is generated, and in step 108, the corrected NC machining data is transferred to the CNC device 40 for processing 1.
End 00.

"Effects of the Invention" As explained above, the present invention has the above configuration, measures the shape of the cutting edge of the cutting tool, calculates the machining point that changes in relation to the machining surface, and calculates corrected NC machining data. The excellent effect is that it is possible to process any aspherical surface shape with ultra-precision, eliminating errors caused by the shape of the cutting edge of the cutting tool, with a simple machine configuration of two orthogonal axes. There is.

[Brief explanation of the drawing]

1 to 5 show an embodiment of the present invention, FIG. 1 is a front view showing the configuration of the embodiment, FIG. 2 is a front view showing the shape measuring device, and FIG. 3 is a main part. 4 is a plan view showing the relationship between the shape of the machined surface and the shape of the cutting edge of the cutting tool. FIG. 5 is a flowchart showing the process, and FIGS.
I is a plan view of a conventional device, and FIGS. 8 and 9 are plan views showing the relationship between the shape of the machined surface and the shape of the cutting edge. 13., Z-axis table, 16. ,,main axis, 23
゜5, X axis element - pull, 26,,, bite, 3
0. ,,Laser length measurement system, 40. ,,CNC-1
Placement, 50, , NC processing data processing device, 56
,,,Machine surface shape manual means, 60111111 shape measuring device. Figure 2 Figure 2 Figure 2 Figure 2 Figure 2 Figure 2 Figure 2 Figure 2

Claims (1)

[Scope of Claim] An aspherical surface processing machine that turns a curved surface by controlling two orthogonal axes using a numerical control device (CNC device) to move the cutting tool relative to the workpiece, A cutting edge shape measuring means for measuring the cutting edge shape, a cutting edge shape memory means for storing the cutting edge shape, a processing surface shape inputting means for inputting the processing surface shape of the workpiece, and a processing surface shape memory for storing the processing surface shape. a machining point calculating means for calculating a machining point of the cutting edge of the cutting tool that comes into contact with the machining surface for each position on the machining surface based on the stored cutting edge shape and machining surface shape; and each movement of the NC machining data. An aspherical surface machining machine comprising: NC machining data correction means for creating NC machining data in which a cutting tool edge shape is corrected based on the machining point for each position.