JPS59124546A - Device for positioning body - Google Patents

Abstract

PURPOSE:To carry out positioning control with high accuracy, by using a laser means to detect the x-direction displacement of a table carrying a tool rest, due to the error in the squareness of a guide or the like, to control a voltage impressed upon piezoelectric elements supporting a tool holder. CONSTITUTION:When a table 2 is displaced by DELTAx toward a reference mirror 26 due to the error in the squareness of a guide 1 or the inaccuracy of a drive system as the table is slid, laser light f2 generated by a laser oscillator 28 and transmitted to a receiver 27 through a polarized beam slitter 25, a cube corner 21, etc. undergoes a Doppler frequency modulation by the displacement DELTAx. The output of the receiver 27 is processed by a counter 29 to apply a displacement signal to a controller 30. The controller then supplies a controlled voltage to piezoelectric elements 8, 9 pinch-holding the flange of a tool holder 6, to move a tool 7 by DELTAx toward a workpiece 10. The position of the tool 7 is thus corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a cutting device, and more particularly to a device for positioning tools and the like with high precision.

[Prior art]

Precise positioning of tools in conventional cutting involves measuring the position of a table equipped with a tool rest with a laser length measuring device, and table position errors are fed back to the motor or hydraulic cylinder that drives the table. ,
The position of the table was corrected. Therefore, changes in posture when the table slides, that is, changes in the position of the cutting edge due to yawing, rolling, and pitching, are not measured.Furthermore, even when compensating for displacement due to parallel movement of the table, the entire table equipped with the tool rest is rotated by the feed screw. Alternatively, since the fine movement is corrected by differential pressure of the hydraulic cylinder, etc., it takes time from position detection to position correction, which has the drawback of deteriorating the accuracy of the machined shape.

[Purpose of the invention]

The purpose of this invention is to eliminate the above-mentioned drawbacks of the prior art,
It is an object of the present invention to provide a positioning device for an object to be positioned, which accurately measures the position of a tool or the like and precisely controls the positioning of the tool or the like, regardless of the posture of a table.

[Summary of the invention] A base thread plane mirror is installed parallel to the sliding direction of a table on which a tool post is mounted, a three-sided reflector (keeb corner) is attached to the rear end of the tool (or workpiece) holder, and The distance to the rear end of the tool (cutting or workpiece) holder is directly measured to determine the position of the tool (cutting or cutting), and the tool (or workpiece) is connected to the holder via a piezoelectric element. The piezoelectric element is fixed to a tool post, and positioning errors are corrected by controlling the voltage applied to the piezoelectric element.

[Embodiments of the invention]

The present invention will be explained below based on the drawings. Figure 1 shows
FIG. 2 is a plan view of an embodiment of the present invention, and FIG. 6 is an explanatory diagram of the operation of an embodiment of the present invention. The present invention will now be described in detail with reference to FIG. Table 2 sliding on guide 1
is equipped with a tool rest, 5, which is hollowed out inside.
The tool rest 5 is made of a material with an extremely small coefficient of linear expansion,
A tool holder 6, which is equipped with a tool 7 at one end and a key corner 21 at the other end, is held in the cutting direction by piezoelectric elements 8.9, which have flanges provided on its outer periphery and attached to both sides of the tool holder 6. It is fixed inside the stand 5. Also,
A reference mirror 26 is provided parallel to the sliding direction of the table 2 and with its reflective surface facing the cube corner 21, and between the reference mirror 26 and the cube corner 21,
Polarizing beam splitter 25, λ/4 polarizing plate 26.24,
An optical path length measuring section consisting of a key corner 22 and a receiver 27 is fixed on the table 2. 29 shows a counter for arithmetic processing of the output signal from the receiver 27, and the error in the distance between the key corner 21 and the reference mirror 26 with respect to the reference value is calculated here. The controller 6o controls the piezoelectric element 8 according to the error value.
．． 9, change the voltages (1) and (2) applied to the tool holder B so that the error in the relative distance between the key corner 21 at one end of the tool holder B and the reference mirror 26 becomes 0. Perform positioning control. Note that 1o represents a workpiece, and 28 represents a laser oscillator.

FIG. 2 is an explanatory diagram of length measurement using a laser, in which a laser oscillator 28 generates coherent laser beams of frequencies f1 and f2. The laser beam f1 passes through the polarizing beam splitter 25, is reflected at the give corner 22, passes through the polarizing beam splitter 25 again, and enters the receiver 27.

The other laser beam f2 is reflected by the polarizing beam splitter 25 and directed toward the cube corner 21.
1 and returns to the polarizing beam splitter 25,
During this time, the laser beam f2 passes through the λ/4 polarizing plate 26 twice, so the phase of the polarization plane shifts by 90', passes through the polarizing beam splitter 25, is further reflected by the reference mirror 26, and is sent to the discarded polarizing beam splitter 25. come back to. During this time, the laser beam f2 passes through the λ7/4 polarizing plate 24 twice, so
The polarization plane is rotated by 90°, and the polarization beam splitter 25
After being reflected at the cube corner 22, polarizing beam splitter 25, λ/4 polarizing plate 24, reference mirror 26, λ/4 polarizing plate 24, polarizing beam splitter 25, λ/4 polarizing plate 2
The light passes through the 6-cube corner 21, the λ/4 polarizing plate 23, and the polarizing beam splitter 25, and finally enters the 7-bar 27.

Next, the invention will be explained in detail with reference to FIG. 1. Assume that the table 2 slides by y and moves from position d to position a' in the figure, and at this time, due to the straightness error of the guide 1 and also the error of the drive system, the table 2 moves ΔX toward the reference mirror 26. If the tip is displaced by ΔX, the tip of the tool 7 will also be separated from the workpiece 10 by ΔX. In this case, the laser beam f2 is subjected to Doppler frequency modulation by the displacement amount ΔX of the table 2, detected by the receiver 27, arithmetic processed by the counter 29, and a displacement amount signal is transmitted to the controller 30. The controller 60 controls the voltage applied to the piezoelectric element 8.9 that clamps the flange portion of the tool holder B. The voltage applied to the piezoelectric element 8.9 and the elongation due to the applied voltage are in a proportional relationship, and a bias voltage corresponding to the displacement ΔX is applied to the piezoelectric element 9 on the cube corner 21 side of the holder B. . In addition to this, a voltage (18) corresponding to the displacement amount ΔX is applied to the piezoelectric element 8 on the tool 7 side as a bias voltage (2). By applying a voltage subtracted from , the tool 7 moves by ΔX toward the workpiece 10, and as a result,
Since the tool 7 is always at the same position with respect to the workpiece 10, it is possible to cut with high precision.

Incidentally, here, a positive bias voltage (■) is applied to both the piezoelectric elements 8 and 9. The reason for applying this bias voltage is ■. However, since the piezoelectric element 8.9 is restricted from elongating by the tool post 5, the compressive force causes the piezoelectric element 8.9 to expand. 6, the supporting rigidity of the tool 7 can be increased, and it can be made almost unaffected by external vibrations and cutting forces.

The tool 7 and the workpiece 10 of this embodiment are installed in place of each other, the fixed workpiece 10 is machined with the rotating tool 7, and the support part of the workpiece 10 is attached to the piezoelectric element 8.9. The piezoelectric element 8.9 is fixed to the table 2 through the piezoelectric element 8.
The same effect as described above can be obtained even if minute positioning control is performed.

Although the above description is about cutting a flat surface, a second table having a guide in a direction perpendicular to the sliding direction of the table 2 and capable of cutting in the direction perpendicular to the sliding direction of the table 2 is used.
The tool rest is fixed on the second table through a guide, and the table 2 and the second table are moved according to a preprogrammed movement trajectory, and a tool holder 6 and a reference mirror 26 similar to the above are attached. Accurately read the relative distance between the piezoelectric elements 8.9 and 10.
Cutting device or second table cutting device and the piezoelectric element 8.9
By providing feedback as a depth-of-cut correction instruction, high-precision finishing can be achieved even when cutting an axially symmetrical curved surface.

〔Effect of the invention〕

As explained above, according to the present invention, the position of the tool can be determined with an extremely fast response speed in response to changes in posture during sliding of the table on which the tool rest is mounted during cutting, or table sliding errors due to straightness errors of the guide. This has the effect of providing a cut surface with highly accurate straightness.

[Brief explanation of drawings]

FIG. 1 is a plan view of an embodiment of the present invention, FIG. 2 is an explanatory diagram of a laser beam length system, and FIG. 6 is an explanatory diagram of the operation of an embodiment of the present invention. Explanation of symbols 1...Guide 2...Table 6...Knob 4...Feed screw 5...Turret
6...Tool holder 7...Tool
8.9... Piezoelectric element 10... Workpiece 21. 22... Keyve corner 2, 24... λ/4 polarizing plate 25... Polarizing beam splitter 26... Reference mirror 27... Resinoku 28
...-Laser oscillator 29...Counter 60...Controller representative patent attorney Junnosuke Nakamura 1 Figure 1 JU 2nd 17'2 Figure

Claims (2)

[Claims] (1) In a cutting machine that provides relative motion between a tool and a workpiece, there is a tool holder that fixes the tool at the tip, a tool post that supports the tool holder via a piezoelectric element, and a tool boulder that supports the tool holder through a piezoelectric element. A keep corner with an optical axis in the cutting direction fixed on the opposite side of the tool, a table that slides at right angles to the cutting direction and equipped with a tool rest, and a table that is parallel to the moving direction of the table and perpendicular to the cutting direction. A reference mirror with a flat reflective surface and fixed independently from the above table,
A tool position measuring system is provided between the reference mirror and the cube corner and fixed on the table to measure the distance between the cube corner and the reference mirror. At least one pair of opposing piezoelectric elements to which a bias voltage is applied are arranged in the measurement system to apply a compressive load to the tool holder, and the tool position measurement system A positioning device for an object to be positioned, characterized in that the error in the relative distance between the tool and the reference mirror measured by the method is removed by controlling the potential difference applied to the opposing piezoelectric elements. (2) A holder is provided in place of the above-mentioned tool, and the error in the relative distance between the above-mentioned workpiece and the reference mirror can be controlled by controlling the potential difference applied to the above-mentioned opposing piezoelectric element. 2. A positioning device for an object to be positioned according to claim 1, wherein the device is configured to remove the object by removing the object.