CH652959A5 - DEVICE AND METHOD FOR GRINDING AND POLISHING, IN PARTICULAR OF METAL OBJECTS, WITH A FLEXIBLE TOOL. - Google Patents

Description

The invention relates to a device according to the preamble of claim 1 and a method for its operation.

It should be noted that a device according to the invention is not a precision grinding machine, which also results from the use of a flexible tool.

In the case of flexible tools, it is known that the time-chip volume is practically constant with constant tool contact pressure on the workpiece. Grinding and polishing processes of this type should therefore be carried out with the most exact possible maintenance of the contact pressure, especially in the case of cycle lines where the changes take place at certain intervals.

So far, one has managed to compensate for the wear of the workpiece by temporarily adjusting it by hand, which becomes unsatisfactory with increasing working speeds and with increasing automation.

The object of the invention is to remedy these deficiencies and to provide a device and a method which allow the contact pressure to be maintained precisely.

To achieve this object, a device according to claim 1 and a method for its operation are proposed.

The economically advantageous device automatically allows the power consumption of the drive motor to be determined, compared with the setpoint and corrected in the event of setpoint deviations, for which purpose the servomotor is started until the setpoint matches. The method according to the invention according to claim 5 also runs in this way.

Now, as is well known, you have to increase the distance between the tool and the workpiece during a workpiece if you want to move in and out comfortably. For this purpose, according to the invention, an additional workpiece change distance change drive can be used, but then the described contact pressure distance adjustment should be blocked so that it does not reduce the distance by continuing to run and gives rise to an excessive contact pressure when retracting after the workpiece change.

On the other hand, the actuator itself can also be used for an additional workpiece change movement, but for the same reasons, the control of the contact pressure control should temporarily be shut down.

Preferably, the current consumption and the voltage will be tapped from the supply line of the drive motor, and the values thus determined are evaluated in a multiplier, with which e.g. Compare a potentiometer on a display with the setpoint and evaluate the result in a reversing switch with the off position.

In this case, the control can be shut down during the workpiece change, both when the workpiece change distance adjustment is carried out separately and with the servomotor. This in the sense of the method according to the invention.

The invention is described below with reference to the single drawing figure, for example, wherein it is noted that it is a purely schematic illustration with a simplified control that is shown.

The workpiece 1 (e.g. a metal pot whose surface is to be finished) is attached to a holder, not shown. In the case of using the device in a work street, e.g. in the form of an automatic rotary table, the workpiece holder can be movable so that it can move from device to device.

In order to be able to remove the tool 20 from the workpiece 1 for a workpiece change, the drive motor 2 is mounted in an auxiliary slide 30 which is mounted on the main slide 3 such that it can be moved back and forth to a limited extent in one step by the workpiece change drive 31. This workpiece change drive 31 can e.g. pneumatically, hydraulically, electrically or by any combination of such drive means. It can be influenced by an associated switching device 32.

The main slide is in turn displaceable on the vertical columns 40 of the base 4 by an adjusting spindle 50, the adjusting spindle 50 being driven by the adjusting motor 5. For this purpose, the servomotor 5 is fastened on a bracket 51 on top of the columns 40.

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The servomotor 5 is stationary or runs forwards or backwards depending on the position of a reversing switch 60, as a result of which the distance between the workpiece 1 and the tool 20 and thus the contact pressure of the tool 20 on the workpiece 1 can be kept exactly constant.

In order for this to be possible, the power consumption of the drive motor 2 is tapped at its feed line and determined by the multiplier 61. The signal of the multiplier 61 is compared in the comparator 64 with the desired value set by the potentiometer 62 on the display 63. The reversing switch 60 is switched accordingly by the signal of the comparator 64.

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So that the lifting of the tool 20 from the workpiece 1 by the corresponding drive 31 does not lead to undesired readjustment movements of the servomotor 5 during a workpiece change, the control unit 60-64 is shut down by the switching unit 32.

The device described is economically and practically particularly suitable for grinding and polishing processes, the border between grinding and polishing being known not to be clearly defined.

This device can be used according to the inventive method of claims 5 to 7, which need not be explained further.

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1 sheet of drawings

Claims (7)

652959 PATENT CLAIMS 1.Device for grinding and polishing, in particular of metal objects, with a flexible tool which can be driven in rotation by an electric drive motor and can be placed under a predeterminable contact pressure on a workpiece attached to a workpiece holder, characterized in that a control member (60 -64) for controlling the distance between the tool (20) and the workpiece (1) by means of a servomotor (5) depending on the power consumption of the drive motor (2). 2. Apparatus according to claim 1, characterized in that in addition to said contact pressure regulating distance adjustment, a workpiece change distance adjustment (31) for intermittent mutual distance change between tool (20) and workpiece (1) is provided, wherein during the actuation of this workpiece change distance adjustment (31 ) the contact pressure regulating distance adjustment (5) is blocked. 3. Device according to one of claims 1 and 2, characterized in that the control member (60-64) a current and voltage in a supply line of the drive motor (2) evaluating multiplier (61), a power display instrument (63), a setpoint adjusting member (62 ), a setpoint-measured value comparison element (64) and a reversing switch (60) with an off position for controlling the servomotor (5). 4. Device according to one of claims 1 to 3, characterized in that a switching element (32) which shuts down the control element (60-64) is provided in the circuit of the workpiece change distance adjustment (31). 5. The method for operating a device according to claim 1, characterized in that the power consumption of the drive motor (2) is automatically determined and compared with a predetermined target value, whereupon a servomotor (5) is automatically put into operation in the event of a target value deviation until the tool workpiece -Distance was changed so that the power consumption of the drive motor (2) corresponds to the setpoint. 6. The method according to claim 5 for operating a device according to claim 2, characterized in that the controller (60-64) is shut down during a workpiece change, while a workpiece change distance adjustment with the servomotor (5) or with a special drive (31) is carried out. 7. The method according to claim 6, characterized in that a special drive (31) is used for the workpiece change distance adjustment.