JPH052166B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for measuring the positioning accuracy of an NC machine tool.

[Conventional technology]

NC machine tools perform machining by attaching a cutting tool to the spindle and rotating it while simultaneously moving a workpiece fixed on a table relative to each other using numerical control. Therefore, the relative positioning accuracy (positioning accuracy) of the spindle and table relative to numerical commands is the lifeblood of this NC machine tool, and the performance of the NC machine tool is determined by this positioning accuracy. .

Conventionally, the positioning accuracy of NC machine tools has been determined by actually performing the machining and inspecting the shape accuracy and dimensional accuracy of the workpiece, such as roundness, cylindricity, and flatness. Judgments are made based on the variation.

[Problem that the invention seeks to solve]

As mentioned above, in the past, the accuracy of an NC machine tool could only be determined by actually performing the machining and measuring the workpiece. Therefore, from the setup of the workpiece to its accuracy determination, There was a problem in that it required a lot of effort and time.

[Means for solving problems]

In the NC machine tool according to the present invention, a main shaft that rotates an attached cutting tool and a table that fixes a workpiece can be moved relative to each other in the direction of the distance and in the plane direction intersecting the direction of the distance, with a distance between them.
In an accuracy measuring device for an NC machine tool, a linear scale having spheres at both ends is attached to the main shaft in place of the cutting tool, and one of the spheres is rotatably adsorbed with the center axis of the main shaft as the center of rotation. One spherical seat that supports, the other spherical seat that is fixed on the table instead of the workpiece and that rotatably suction-supports the other sphere, and a format that corresponds to the movement locus of the two spherical seats. an output device that outputs the measured value of the linear scale;
The error on the NC machine tool side is measured with respect to the closed curve locus between the two spherical seats obtained by relatively moving the spindle and table in the plane direction and returning to the original positional relationship.

[Effect]

In the accuracy measuring device for an NC machine tool according to the present invention, the main axis and the table are connected via the spherical seat of the sphere even though the main axis is an inclined linear scale having spheres at both ends. The circular motion of the table can be displayed as a degree of circularity in degrees, for example, on a TV cathode ray tube or a printer.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing the usage state of this embodiment, and FIG. 2 is a diagram showing an example of data representing the roundness measured thereby.

As shown in FIG. 1, spheres 2 and 3 are fixed to both ends of a telescoping linear scale 1. As shown in FIG. Then, one spherical seat 5 is attached to the main shaft 4 of an NC machine tool (not shown), and the other spherical seat 6 is fixed to the table 7. Each spherical seat 5, 6 is provided with exhaust holes 10, 11 connected to a vacuum pump (not shown) via hoses 8, 9.

Next, we will explain how to measure the accuracy of this NC machine tool.

The sphere 2 of the linear scale 1 is attracted to the center of the spherical seat 5 attached to the main shaft 4, and the other sphere 3 is attracted to the spherical seat 6 fixed at an arbitrary position on the table 7. The center of the table 7 is rotatably connected to any arbitrary position of the table 7 by means of an inclined linear scale 1.

Next, when the table 7 is caused to move in a circular manner under numerical control, the linear scale 1 also moves around the center of the main shaft 4 following the movement. This circular movement of the table 7 is displayed as measurement data of roundness as shown in FIG. 2, for example, on a TV cathode ray tube or a printer. As a result, it is possible to easily and immediately obtain necessary data regarding the degree of eccentricity at a certain angle, the overall variation, the degree of variation in clockwise and counterclockwise rotations, the repeatability, etc. Therefore, based on these data, it is possible to determine the causes of variations in table positioning accuracy, such as errors in machining of the table drive mechanism, wear or damage to the ball screw, variations in the rotational speed of the drive motor, etc. can be pursued and corrected accurately and quickly.

〔Effect of the invention〕

As described above, according to the present invention, the center of the spindle and any position on the table are connected via the spherical seat with an inclined linear scale having spheres at both ends, so that the center of the main shaft and any position on the table can be freely rotated. Accordingly, the linear scale performs a turning movement around the center of the main axis, and thereby the circular movement of the table can be displayed as roundness for each angle on, for example, a TV cathode ray tube or a printer.
This measuring device is extremely easy to install and can easily and quickly measure the accuracy of NC machine tools, making it extremely convenient.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a usage state of an embodiment of the present invention, and FIG. 2 is a diagram showing an example of measurement data. 1... Linear scale, 2, 3... Sphere, 4...
...Main shaft, 5, 6... Spherical seat, 7... Table.

Claims (1)

[Claims] 1. In an accuracy measuring device for an NC machine tool, in which a main shaft that rotates an attached cutting tool and a table that fixes a workpiece are spaced apart and are movable relative to each other in the direction of the distance and in a plane direction that intersects the direction of the distance. , a linear scale with spheres at both ends,
one spherical seat that is attached to the main shaft in place of the cutting tool and rotatably suction-supports one of the spheres with the center of rotation about the central axis of the main shaft;
The other spherical seat is fixed in place of the workpiece on the table and rotatably suction-supports the other spherical body, and the measured values of the linear scale are measured in a format corresponding to the movement locus of the two spherical seats. and an output device for measuring an error on the NC machine tool side regarding a closed curve trajectory between the two spherical seats obtained by relatively moving the spindle and table in the plane direction and returning to the original positional relationship. An accuracy measuring device for NC machine tools characterized by: