JPH01310859A - Polishing machining device - Google Patents

Abstract

PURPOSE:To improve machining efficiency by increasing a machining pressure exerted on a work, by a method wherein according to an applying current, a sleeve and a yoke are magnetized, and an electromagnetic coil to exert a down energizing force on a plunger is situated on the outer periphery of a magnetic sleeve located to the lower end of a drive shaft. CONSTITUTION:When a drive shaft 12 is caused to approach a polishing surface plate 10 to relatively rotate the two members 10 and 12, a work holder 15 rotatably supported in a floating manner to the lower end part of the drive shaft 12 is levitated slightly from the polishing surface plate 10, and a work W secured on the under surface of the holder 15 is machined by means of machining liquid flowing between the polishing surface plate 10 and the work. In this case, a current is applied on an electromagnetic coil 27, a sleeve 20 and a yoke 22 are magnetized according to the applying current, and a down energizing force is exerted on a plunger 25. The energizing force is transmitted to a work holder 15 through a rod 26 and a pressure converting mechanism 30, and a machining pressure exerted on the work W is increased, resulting in the possibility to machine the work W with high efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a polishing machine that processes the surface of a workpiece into a highly accurate mirror surface using a processing fluid containing fine abrasive grains.

(Prior Art) In a conventional polishing machine of this type, a drive shaft and a polishing surface plate supported on a machine frame so as to be relatively rotatable around a vertical axis and relatively accessible in the vertical direction, and a polishing surface plate of the drive shaft A work holder is provided at the lower end that is floatingly supported so that only rotational motion can be transmitted, and the working fluid is circulated between the workpiece and the polishing surface plate by relative rotation of the workpiece fixed to the lower surface of the work holder and the polishing surface plate. The workpiece and the work holder are slightly floated above the polishing surface plate by the dynamic pressure generated by the processing fluid, and the workpiece is processed. It is known that the processing amount per unit time of a polishing machine increases with the total pressure (processing pressure) applied to the processing surface of the workpiece, but in conventional equipment, this processing pressure is reduced by floating support on the drive shaft. It is uniquely determined by the total weight of the work holder, workpiece, etc.

(Problems to be Solved by the Invention) In such conventional technology, since the machining pressure cannot be increased as it is, the amount of machining per unit time cannot be increased, and therefore it is difficult to improve the machining efficiency. I can't come. For this reason, it is possible to prepare multiple work holders with different mold cavities and select the appropriate one for use, or to increase the machining pressure by attaching and detaching a heavy cone to the work holder. However, the operation is troublesome, and the processing pressure cannot be easily changed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a polishing machine that can increase and change the processing pressure with simple operation.

(Means for Solving the Problems) For this purpose, the polishing machine according to the present invention is capable of relative rotation around a vertical axis and relative access in the vertical direction, as illustrated in FIGS. 1 and 2. A drive shaft 12 and a polishing surface plate 10 are supported by a frame, and a work holder 15 is floatingly supported at the lower end of the drive shaft 12 so that only rotational motion can be transmitted, and a workpiece W is fixed to the lower surface of the work holder. By the relative rotation of the polishing surface plate 10 and the polishing surface plate 10, machining fluid is caused to flow between the workpiece and the polishing surface plate, and the dynamic pressure generated by this machining fluid is used to move the workpiece W and the work holder]5 from the polishing surface plate 10. In a polishing machine that processes the same workpiece while slightly floating, a cylindrical sleeve 20 made of a ferromagnetic material is integrally formed at the lower end of the drive shaft 12, and a magnetic The drive shaft 12 is arranged at intervals between
a yoke 22 made of a ferromagnetic material fixed to the lower end of the
a plunger 25 that extends from the sleeve 20 to the yoke 22 and is guided and supported in an inner hole 23 of the sleeve so as to be axially movable; and a rod that is coaxially fixed to the plunger and projects downward from the yoke 22 toward the work holder 15. 26, a pressure transducer 30 interposed between the lower end of this rod and the work holder 15, and the sleeve 20.
It is characterized by comprising an electromagnetic coil 27 which is provided on the outer periphery of the plunger 25 and magnetizes the sleeve and the yoke 22 in response to an applied current to apply a downward biasing force to the plunger 25.

(Function) When the drive shaft 12 is brought close to the polishing surface plate 10 and the drive shaft 12 and polishing surface plate 10 are rotated relative to each other, the workpiece W and the work holder 15 are slightly floated above the polishing surface plate 10. The workpiece W is processed by a processing fluid flowing between it and the polishing surface plate 10. A downward biasing force is applied to the plunger 25 according to the current applied to the electromagnetic coil 27, and this biasing force is transmitted to the work holder 15 via the rod 26 and the pressure transducer 30 to apply processing pressure to the workpiece W. increase. Also, this biasing force is applied to the pressure converter 3.
Detected by 0.

(Effects of the Invention) As described above, according to the present invention, the machining pressure applied to the workpiece can be increased by the simple operation of applying current to the electromagnetic coil, and the machining efficiency can be improved. Even during processing, the processing pressure can be changed to a desired value by adjusting the current applied to the electromagnetic coil.

(Example) The present invention will be explained below using examples shown in the accompanying drawings.

In FIG. 1, a polishing surface plate 0 is rotatably supported on a machine frame (not shown) so as to be rotatable around a vertical axis, and an elevating rod 11 is moved relative to the polishing surface plate 10 by an unillustrated elevating cylinder provided on the machine frame. It is designed to be moved up and down. A drive shaft 12 is rotatably supported on the lifting head 11 around a vertical axis, and a work bolt 1 is mounted on the lower end of the drive shaft 12.
5 is supported in a floating manner. Polishing surface plate 1
A peripheral wall is provided on the outer periphery of the polishing plate 10 to accommodate a machining liquid in which fine abrasive powder and the like are suspended, and the rotating axes of the polishing surface plate 10 and the drive shaft 12 are offset by a considerable distance.

As shown in FIGS. 1 and 2, a pair of pins 13 are fixed to protrude from the outer cylindrical portion of the lower outer periphery of the drive shaft 12 at an interval of 180 degrees. A pair of axially long courses 16 that can be engaged with the pin 13 are formed on the inner periphery of the work bolt 15 . Insert the outer cylindrical portion 12a of the drive shaft 12 into the inner periphery of the work holder 15 so that the pin 13 engages with the axial long groove 16, and remove the pin 13 with one ring nut screwed onto the upper part of the work holder 15. To prevent this deviation, the work holder 15 is floatingly supported at the lower end of the drive shaft 12 so that only rotational motion can be transmitted.

A support plate 17 is removably fixed to the lower surface of the work holder 5 via a locking ring nut 18, and a workpiece W is bonded to the lower surface of the support plate 1-17 with wax or the like.

The drive shaft 12 is made of a ferromagnetic material such as iron, and as shown in FIG. 1, a cylindrical sleeve 20 is coaxially integrally formed at its lower end. A cylindrical yoke 22 made of a ferromagnetic material such as iron is in contact with the lower end of the sleeve 20 via a spacer ring 21 made of a non-magnetic material such as brass.
2 is fitted and attached within the outer cylindrical portion 12a at the lower end of the drive shaft 12. Sleeve 20, spacer ring 21
An inner hole 23 is formed in the upper part of the yoke 22, and a plunger 25 made of a ferromagnetic material such as iron is guided and supported in the inner hole 23 so as to be able to pivot from the sleeve 20 to the yoke 22. A rod 26 made of a non-magnetic material coaxially fixed to the plunger 25 is attached to a through hole 2 at the center of the yoke 22.
The plunger 25 and rod 26 protrude downward through the inner hole 23, and are urged toward the inner bottom surface of the work holder 1.5 by a spring 24 provided in the inner hole 23.

The lower end of the rod 26 is in contact with the upper surface of a pressure transducer 30 such as a load cell provided at the center of the inner peripheral surface of the work holder 15, and the pressure transducer 30 is connected to the work holder 15 from the plunger 25 via the rod 26. It converts the biasing force applied to an electrical signal into an electrical signal. In addition, the yoke 22, the spacer ring 21 and the drive shaft 12 on the outer periphery of the sleeve 20
An electromagnetic coil 27 wound around a bobbin 28 is provided between an annular chamber formed by the outer circumferential portion 12a. Two sets of slip rings 31.3 are attached to the lower outer periphery of the drive shaft 12.
Correspondingly, two sets of brushes 33 and 34 are provided on the elevating rod 11. Electromagnetic coil 27
An applied current is supplied from the load control device 35 through the brush 33 and the slip ring 31, and the urging force from the plunger 25 to the work holder 15 is detected by the pressure transducer 30 and applied through the slip ring 32 and the flange 34. It is fed back to the load control device 35.

When the lifting head 11 and one drive shaft 12 are raised by the lifting cylinder of the enclosure, the pin 3 engages with one ring nut and the work holder 15 is suspended and supported.
In this state, the support plate 17 to which the workpiece W to be machined is adhered is attached to the workpiece holder 15 via the locking ring nut 18.

Next, the polishing surface plate 10 and the drive shaft are rotated, the lifting cylinder is operated, and the lifting head 11 is lowered to the predetermined position shown in the figure and stopped. The work holder 15, the support plate 17, and the workpiece W float against the weight of the workpiece W due to the dynamic pressure generated by the machining fluid stored in the polishing surface plate. Polishing of the lower surface begins. The load control device 35 first calculates an applied current value based on a machining pressure for the workpiece that is separately instructed, and applies that value of current to the electromagnetic coil 27 . As a result, the sleeve 20 and the yoke 22 are magnetized, and the plunger 25 whose lower end is near the upper end of the yoke 22
A downward biasing force corresponding to the applied current is applied to the workpiece eAW, and this biasing force is transmitted to the work holder 15 via the rod 26 and the pressure exchanger 30, thereby increasing the machining pressure applied to the workpiece eAW by that amount. The pressure transducer 30 detects the force transmitted from the plunger 25 to the work holder 15 and feeds it back to the load control device 35, which causes the load control device 35 to modify the current applied to the electromagnetic coil 27.
To accurately increase the machining pressure on a workpiece W to a commanded value. According to this embodiment, the machining pressure can be increased with high precision, so that the machining efficiency can be improved.

Although the above description has been made for the case where the machining pressure is constant, the above embodiments can also be implemented by varying the machining pressure over time, as shown in FIG. 3, for example. In this way, although the machining pressure increases as a whole and machining performance improves, the machining pressure at the initial stage of machining, when the run-in is insufficient, can be reduced, reducing machining defects, and the machining pressure at the final stage of machining can be reduced. It is possible to improve finishing accuracy by reducing

[Brief explanation of the drawing]

1 and 2 show an embodiment of the polishing machine according to the present invention, FIG. 1 is a vertical sectional view of the main part, and FIG.
FIG. 3 is a cross-sectional view taken along line 1--2 in the figure, and is a diagram showing an example of program control of processing pressure. Explanation of symbols 10 Polishing surface plate, 12 Drive shaft, 15
- Work holder, 20 - Sleeve, 22 - Yoke, 23 Inner hole, 25... Plunger, 26 -
... Rod, 27 ... Electromagnetic coil, 30 ... Pressure transducer, W ... Workpiece.

Claims (1)

[Claims] A drive shaft and a polishing surface plate are supported on a machine frame so as to be relatively rotatable around a vertical axis and relatively accessible in a vertical direction, and a work holder is floatingly supported at the lower end of the drive shaft so that only rotational motion can be transmitted. By the relative rotation of the workpiece fixed to the lower surface of the work holder and the polishing surface plate, machining fluid flows between the workpiece and the polishing surface plate, and the dynamic pressure generated by this machining fluid causes the workpiece and work holder to flow together. In a polishing machine that processes the workpiece by slightly floating it above the polishing surface plate, a cylindrical sleeve made of a ferromagnetic material is integrally formed at the lower end of the drive shaft; a yoke made of a ferromagnetic material that is magnetically spaced from the lower end and fixed to the lower end of the drive shaft; and a plunger that is guided and supported in an inner hole of the sleeve so as to be able to pivot from the sleeve to the yoke. a rod coaxially fixed to the plunger and protruding downward from the yoke toward the work holder; a pressure transducer interposed between the lower end of the rod and the work holder; A polishing machine comprising an electromagnetic coil provided on the outer periphery and magnetizing the sleeve and the yoke according to an applied current to apply a downward biasing force to the plunger.