JPS5840247A - Precision positioning device - Google Patents

Abstract

PURPOSE:To improve positioning accuracy between a tool and a workpiece, by measuring an X-Y table or spindle displacement by temperature variations, etc., with a laser length measuring instrument respectively, while making the produced errors controllable to compensate for. CONSTITUTION:After grooving an optional position X1 of a workpiece 1 mounted on an X-Y table 2 with a tool 34, when the center of the tool 34 is positioned at the next desired position X2, the table 2 is moved by rotation of a feed motor 71, and at a point when the travel amount measured by laser length measuring systems 51-54, which measure the displacement of the table 2, corresponds with a desirable pitch P or a distance L from a zero position 0, the table 2 is stoppped. In addition, a spindle 31 is displaced by room temperature variations, etc., an error DELTAP at a position X3 of the tool 34 is measured by laser length measuring systems 61-64, which measure the displacement of the spindle 31, the motor 71 is rotated by command from an operation processor 9 and the center of the tool 34 is so controlled that it is corrected to the desired position X2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for positioning a tool and a workpiece with high precision in machine tools such as cutting machines, grinding machines, and milling machines.

An example of a prior art 6-positioning device in a cutting machine is shown in FIG. In the figure, when grooving or cutting the workpiece 1 at arbitrary intervals, the pitch indexing direction of the X-Y table 2 (hereinafter referred to as
The laser oscillator 41 and the '10 interface determine the amount of movement in the Fuis 42, interferer 51
, a reflector 52, a receiver 56, a counter 54, an arithmetic processing device 9, etc., are measured by a length measuring device such as a laser length measuring system, and the measurement results are fed back to the motor drive device 72 for precise positioning. . However, in the above method, due to changes in ambient temperature, the spindle 3
1 and the X-Y table 2 expand and contract, making it difficult to accurately set the relative distance in the X direction between the tool 34 that determines machining accuracy (indexing accuracy) and the X-Y table 2. High precision positioning on the micron order is difficult.

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly accurate positioning device that eliminates the drawbacks of the prior art described above and takes into account improvement in product yield and automation of the production process. In order to achieve the above object, the present invention configures a laser length measurement system by providing a reflector for measuring the position in the X direction on the end face of each of the spindles equipped with an X-Y table and a tool. Eliminating errors due to the influence of the environment (temperature changes),
The key point is to accurately set the relative distance between the XY table and the tool.

Embodiments of the precision positioning device according to the present invention will be described below with reference to the drawings. 2 and 6 are diagrams showing the first embodiment, and FIG. 2 shows an outline of a cutting machine equipped with the device of the embodiment, and FIG. 6 shows the X during index correction. -Y
It is an explanatory view for explaining movement of a table. In FIG. 2, the workpiece 1 is placed on the X-Y table 2 in a suitable manner.
This is mounted on the XtY table 2.
A feed screw 8 is connected to the feed screw 8 for movement in the direction (pitch indexing direction), and a feed motor 71 is connected directly or via a reducer (not shown) to the feed screw 8. The feed motor 71 is connected to the arithmetic processing unit 9 via a motor drive device 72. The arithmetic processing unit 9 is preferably a microconbeater or a miniconbeater, and is used as the / of the laser length measurement system.
In addition to a function for reading additional data from the n-interface 42, it is equipped with an indexing amount correction routine and a storage circuit.
The positions of the XY table 2 and the tool 34 are read, and a correction value for a desired indexing amount is calculated. The laser length measurement system includes a laser oscillator 41, a distributor 43 for distributing the laser beam 44 emitted from the laser oscillator 41 into two laser beams 55a and 165a, and the distributed laser beams 55a and 65a and the laser beam. The laser beams 55C165 after being reflected by the reflecting mirrors 52 and 62, respectively
An interferometer 51.61 is fixed at an appropriate position so as to interfere with C, and an interferometer 51.61 receives the laser beams 55d and 65d output from the interferometer 51.61 and converts the results into pulses. A receiver 53.63, counters 54 and 64 for respectively adding and subtracting pulses output from the receiver 56.63, and the counter 54.6.
4 and an I/N interface 42 for connecting the arithmetic processing unit 9.

The reflecting mirror 62 attached to measure the displacement of the main shaft 31 is preferably fixed to an adjustable jig (not shown) in order to eliminate measurement errors due to rotational vibration.

Next, the operation will be explained. As shown in Figure 6,
After grooving an arbitrary position X of the workpiece 1 mounted on the X-Y table 2 with the tool 34, the feed motor 71 is used to position the center of the tool 34 at the next target position X2. Move the X-Y table 2 by rotating the
When the amount of movement measured by a laser length measuring system (numerals 51 to 54) that measures the displacement of the table 2 matches the desired pitch P or the distance from the origin 0, the rotation of the feed motor 710 is stopped; Stop the movement of the X-Y table 2. Furthermore, while the XY table 2 is moved by the pitch P or distance, the main shaft 31 is displaced due to a change in room temperature, etc., and the tool 64 is positioned at the position X3, resulting in an error of ΔP with respect to the target value. This error Δ
.
Rotate the tool 34 in the appropriate direction to position the center of the tool 34 at position
Correct and control to 2. The arithmetic processing unit 9 always performs
Measure the displacement of the table 2 and the main shaft 31, and
The measurement values before and after the movement of the table 2 and the grooving pitch P
Alternatively, it has a memory circuit that stores processing information such as distance 1 from the origin, calculates the positioning error ΔP, and provides a desired output for correction.

FIG. 4 shows the end of the main shaft 31 opposite to the side to which the tool 34 is fixed in a second embodiment of the present invention. As in this example, the reflective surface has extremely high precision (
A reflective mirror 62 finished with a flatness of 0.06 μm or less is glued to the end face of the main shaft g1 so as to be perpendicular to the laser beam 65b, and the displacement of the tool 34 can be investigated by measuring the displacement of the end face. Even when measured, the same effects as in the first embodiment can be obtained. In this case, the main shaft 51, the bearing 62
A reference point on thermal displacement is determined in advance from the configuration of the six components of ball bearings (not shown) that support both, and the distance 11 from the reference point to the center of the tool 34,
The ratio of the distance 12 from the reference point to the reflecting mirror 62 is 12/
By storing Δl in the arithmetic processing unit 9 and measuring the displacement Δl of the end face of the spindle 31, the displacement Δl of the tool 34 can be calculated.
It is approximated to X (a value which also corresponds to ΔP in FIG. 3). That is, the displacement ΔX of the tool 34 is ij X # u , □.

, 1 °°°°°° (1) (where,
α is a coefficient of thermal expansion) and is calculated by the arithmetic processing unit 9.

5 and 6 both show the shaft end of the main shaft 31 on the tool 54 side in a sixth embodiment of the present invention. In the example of FIG. 5, the reflecting mirror 62 and the laser beam 6
A hollow waterproof tube 65 covers 5b and 65C,
It is fixed to the main shaft 61. By blocking the reflecting mirror 62 and the laser beams 65b and 65C from the outside in this way, the interference device 6 that is generated due to the grinding fluid and uneven density distribution is
1 and the reflecting mirror 62 can be eliminated,
Accurate measurements can be made. In the example shown in FIG. 6, instead of the waterproof cylinder 65, the main shaft 61 is formed into a hollow shape having a hollow hole in the axial direction, and the hollow hole is formed in the axial direction similarly to the main shaft. A reflector mount 66 having a reflector 62 bonded to the end face thereof is attached so that the reflector 62 is located approximately at the center of the spindle directly below the tool 54. By doing so, measurement errors can be eliminated as in the example shown in FIG.

FIG. 7 shows a fourth embodiment of the present invention in which the present invention is applied to a lathe. In this embodiment, instead of the tool in the first embodiment shown in FIG. 2, the workpiece 1 is attached to the tip of a spindle (not shown) via a chuck 37, A reflecting mirror 62 is placed at the end face position of
Attach so that the Further, instead of the workpiece, a tool 54 is attached to the 17xy table 2 via a tool mount 68. With this configuration, the workpiece 1 is rotated, the displacement error (expansion/contraction amount) of the workpiece 1 is fed back to the feed motor 71, and the depth of cut of the tool 64 mounted on the X-Y table 2 is calculated. Workpiece 1
can be processed into flat, spherical, or complexly shaped surfaces.

FIG. 8 shows a fifth embodiment of the present invention in the case of a machine tool in which the main shaft 51 is mounted at an angle of θ with respect to the horizontal plane. In FIG. 8, a reflector 62 for measuring the displacement of the main shaft 61 is attached to the end surface of the main shaft on the opposite side to the tool 34 side on the axis of the main shaft. The displacement of the main shaft 31 in the direction of the main shaft axis is X. When closed, the displacements X and y in the horizontal and vertical directions are x = xθ, cosθ °(2
)y = xθ・sinθ...
...(6), the above equation is calculated by the arithmetic processing unit 9, and by moving the main shaft 31 or the bearing 62 in the X direction and the X-Y table 2 in the X direction, the depth of cut l is calculated. (
and pitch indexing amount P can be used for positioning as expected.

As explained above, according to the present invention, the displacement (expansion/contraction amount) of the X-Y table or the main axis due to temperature changes, etc. is measured by a laser length measuring device, and the generated error is corrected.
This control allows accurate positioning and improves product yield.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a cutting machine equipped with a positioning device according to the prior art, Fig. 2 is a block diagram of a cutting machine equipped with an embodiment (first embodiment) of a positioning device according to the present invention, and Fig. 5 is an explanatory diagram for explaining the movement of the X-Y table during index correction in this embodiment, and FIGS. 4 to 8 are illustrations of other embodiments (second to fifth embodiments) of the present invention. It is an explanatory diagram. Explanation of symbols 1... Workpiece 2... X-Y table 8
...Feed screw 9...Arithmetic processing device 31.
... Main shaft 32 ... Bearing 63 ... Flange 64 ... Tool 35 ... Waterproof tube
67... Chuck 38... Tool mounting stand 41.
... Laser oscillator 42 ... I 7 = Interface 46 -7 distributor 51.61 ... Interferer 5
2.62...Reflector 55.65...Receiver 5
4.64...Counter 66...Reflector mount 71
...Feeding motor 72...Motor drive device Patent attorney Junnosuke Nakamura Figure 3 Figure 4 Figure 2 Figure 5

Claims (1)

[Scope of Claims] (1) Consisting of a mechanism section on which a workpiece is placed and a mechanism section equipped with a tool for processing the workpiece □, at least one of the mechanism sections is equipped with a feed screw and a feed screw. In a processing machine capable of moving in at least one axial direction, a plane mirror or a right-angled A first laser length measuring device is provided for reading the position in the direction of forced movement or natural displacement of the mechanism section on which the workpiece is mounted by using the reflection of the laser beam by the prism, and the tool is equipped with the first laser length measuring device. A second laser length measuring device is provided for reading the position in the direction of forced movement or natural displacement of the mechanical part, and
and a precision positioning device that reads the relative distance between the tool and the workpiece from the measurement results of the second laser length measuring device and positions the tool and the workpiece. , (2. In the precision positioning device according to claim 1, the workpiece is placed on a table that is equipped with a feed screw and a feed motor and is movable at least in the indexing direction, and A tool for processing a workpiece is mounted on a rotating spindle, and a plane mirror or right-angle prism is placed on either end of the spindle or at the center of the spindle directly under the #1 tool, and the tool and table are indexed. A precision positioning device characterized in that the relative distance in the indexing direction between the tool and the workpiece is accurately adjusted by reading the relative distance in the indexing direction and moving the feed motor to move the workpiece. (3) In the precision positioning device according to claim 1, a workpiece is mounted on the tip of the rotating main shaft,
and a plane mirror or a right-angle prism is arranged at a position of the spindle axis near the workpiece, and a tool is provided on a tool mount that is equipped with a feed screw and a feed motor and is movable at least in the direction of the spindle axis. , and a plane mirror or a right-angle prism is arranged so that measurements can be made in a direction parallel to the spindle axis, and the relative distance between the workpiece and the tool mount in the spindle axis direction is read, and the feed motor is driven to move the tool. A precision positioning device that accurately adjusts the relative distance between a tool and a workpiece in the direction of the spindle axis by moving the tool. (4) In the precision positioning device according to claim 1, the main shaft equipped with a tool for machining a workpiece at the tip is mounted at an angle to the horizontal plane, and the tool is mounted on the opposite side. A plane mirror or a right-angle prism is provided on the end face of the main shaft to read the horizontal and vertical positions of the tool, and the horizontal positioning of the tool and the workpiece and the positioning of the tool in the direction of the cutting edge are performed simultaneously. Precision positioning device featuring: (5) In the precision positioning device according to claim 1, the device is connected to the first and second laser length measuring devices, and controls by storing and calculating the displacements and specified calculation constants given by the first and second laser length measuring devices. A processing unit for outputting a signal is provided, and the processing unit reads the displacement between the tool and the workpiece in the indexing direction and the displacement in the tool cutting direction, and controls the tool changing motor. Precision positioning device. (6) In the precision positioning device according to claim 1, the plane mirror or right-angle prism is mounted by providing a waterproof tube on the shaft end face of the main shaft on the side and coaxially with the main shaft axis, and attaching the plane mirror or right-angle prism to the shaft end surface of the main shaft. and a laser beam incident on and reflected by the plane mirror or right-angle prism. (7) A reflective mirror mount having a precisely determined position according to claim 1 is provided so that the plane mirror or right-angle prism is disposed at a position of the spindle axis substantially directly below the tool, and the plane mirror or right-angle prism and a laser beam incident on and reflected by the plane mirror or right-angle prism.