Control device for the processing pressure on lapping, honing and polishing machines

• US 4,742,651 A
• Filed: 06/09/1986
• Issued: 05/10/1988
• Est. Priority Date: 06/10/1985
• Status: Expired due to Term

• Current Assignee: Peter Wolters AG (Lam Research Corporation)
• Original Assignee: Peter Wolters
• Inventors: Wittstock, Gerhard
• Primary Examiner(s): Whitehead, Harold D.
• Application Number:
  US06/872,236
• Time in Patent Office: 701 Days
• Field of Search: 51/165.9, 51/165.91, 51/111 R
• US Class Current: 451/24
• CPC Class Codes: B24B 37/005 Control means for lapping machines or devices
• CPC Class Codes: B24B 49/16 taking regard of the load

Abstract

A control device for the processing pressure on honing, lapping and polishing machines, in which the tool is driven by motor via a spindle which is in its turn rotatably and essentially axially fixedly supported in a bearing member which is movable in the direction of the axis of the spindle, in which furthermore a double-acting actuation device engages at the bearing member via resilient means, and in which finally an energy sensor measuring the processing pressure transmits actual pressure signals to a program control which, dependent on time, compares the actual pressure signals with different preset pressure signals and from the comparison of the pressure signals generates adjusting signals for the actuation device. At least the resilient means counteracting the own weight of the tool is formed by a pneumatic adjusting means which is connected to a pressure gas source via a control valve. An adjustable throttle arrangement is connected to the pneumatic adjusting means for the controlled venting of the adjusting means dependent on the adjusting signal of the program control.

Claims

1. A control device for controlling the processing pressure on lapping, honing and polishing machines, in which a tool is driven by motor via a spindle which is in its turn rotatably and essentially axially fixedly supported in a bearing constructional member which is movable in the direction of the axis of the spindle, the device comprising:

(a) a double-acting actuation device for engaging the bearing constructional member by an automatic adjusting means, the automatic adjusting means having an upper pneumatic adjusting means and a lower pneumatic adjusting means, and the automatic adjusting means connected to a gas pressure source by a control valve and by another control valve is connected to an adjustable throttle;

(b) a thrust sensor for measuring the processing pressure of said tool on said workpiece and having means for transmitting pressure signals indicative of the processing pressure;

(c) a program control operatively coupled to the actuation device and the thrust sensor and which periodically compares the actual pressure signals from the thrust sensor with different preset pressure signals and from the comparison of the pressure signals generates adjusting signals for the actuation device;

(d) an adjustable throttle arrangement operatively connected to the double acting actuation device for the controlled venting of the adjusting means in response to the adjusting signal of the program control, said program control being constructed and arranged for lowering the spindle and the tool, respectively, to a position just before the tool touches down onto the workpieces and for venting the upper adjusting means by a control valve and the throttling arrangement, closing the control valve for the upper adjusting means, cyclically opening a control valve for the lowering adjusting means with the aid of clock pulses of the program control, the distances of the clock pulses being adapted to be altered, opening the control valve for venting the lower adjusting means upon reaching a higher loading pressure (F02, F'"'"'02) and closing both control valves upon reaching predetermined upper final loading pressure (F1, F'"'"'1); and

(e) a travel indicator operatively coupled to the tool, the travel indicator detecting both the prolongation of the travel of the tool until the tool touches down onto the workpieces, the distances of the clock pulses changing in dependence upon the prolongation of the travel of the tool, and also the response of an interception switch, said switch adapted to be activated by the tool to transmit a signal to the program control for the purpose of decreasing the tool speed when the tool has approached the workpiece to a predetermined extent.

2. A device according to claim 1, further comprising at least two adjustable throttles connected to the double-acting actuation device by control valves of their own.

3. A device according to claim 1, wherein the bearing constructional member is suspended at one arm of a double-armed lever and the pneumatic adjusting means engages the other level arm.

4. A device according to claim 3, wherein said thrust sensor is arranged between the upper pneumatic adjusting means and one arm of said double-armed lever.

5. A device according to claim 1, further comprising:

(a) an actuated rod connected to the bearing constructional member;

(b) a holding member axially displaceably supported on said actuation rod and selectively adapted to be tightly clamped thereto by means of a locating mechanism connected to the program control; and

(c) said holding member further comprising an adjustable actuation member adapted for having a retracted and extended position for actuating a switch connected to the program control, said switch actuated only when the actuation member is in the extended position.

6. A device according to claim 1, wherein upon deviation of the final loading pressure (F1, F'"'"'1) from the preset value after the control valves have been closed, the control valve for the lower adjusting means is cyclically opened by means of the clock pulses until the final loading pressure (F1, F'"'"'1) has finally reached the preset value.

7. A device according to claim 6, wherein the program control switches on the motor for the spindle when the lower loading pressure (F01, F'"'"'01) has been reached.

8. A control device for processing pressure on workpiece lapping, honing and polishing machines, comprising:

(a) a tool for effecting the workpiece;

(b) a motor drive having a spindle rotatably supported axially in a bearing construction member and movable in the direction of the axis of the spindle for driving the attached tool;

(c) a double-acting actuation device operatively coupled to a bearing constructional member by resilient means for applying tension by said tool on the workpiece; and

(d) program control means for receiving adjustment signals and for varying the tension of said tool on the workpiece by effecting said double-acting actuation device responsive to said adjustment signals.

9. A device according to claim 8, said double-acting actuation device further comprising upper pneumatic adjusting means and lower pneumatic adjusting means operatively connected to a gas pressure source having a control valve and an adjustable throttle arrangement.

10. A device according to claim 9, wherein said program control means further comprises means for varying the tension of said tool on the workpiece by said double-acting actuation device having means for controlled venting of the gas pressure within said double-acting actuation device.

11. A device according to claim 8, wherein said thrust sensor further comprises a sensor arranged between engagement of said double-acting actuation device and said double-armed lever.

12. A device according to claim 8, further comprising an interception switch mounted on and adapted for transmitting adjustment signals to the program control, said adjustment signals effecting a decrease in speed of the lowering of the tool when the tool has approached the workpiece to a predetermined extent.

13. A device according to claim 9, wherein said program control is constructed and arranged to effect lowering of the spindle and the attached tool to a position just prior to engagement between the tool and the workpiece by venting the upper adjusting means.