Abrading – Precision device or process - or with condition responsive... – Computer controlled
Reexamination Certificate
1999-11-30
2001-05-22
Morgan, Eileen P. (Department: 3723)
Abrading
Precision device or process - or with condition responsive...
Computer controlled
C451S010000, C451S011000, C451S021000, C451S410000
Reexamination Certificate
active
06234869
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a machine control gage system, and more particularly to a machine control gage system that measures the size of a workpiece during machining by a machine tool and controls the machine tool so that the size of the products can be uniform.
2. Description of Related Art
An in-process machine control gage system is used for a grinding machine such as a cylinder grinding machine in order to improve machining accuracy and the automation productivity. The machine control gage system measures the size of the workpiece during the machining and controls the grinding machine in real-time to thereby achieve the uniform products.
The size of the workpiece at grinding steps (e.g., a rough-grinding step, a fine-grinding step and a spark-out grinding step) is displayed on a display unit such as a meter and a bar-graph display provided in an in-process control part of the machine control gage system.
The conventional machine control gage system only determines the current size of the workpiece during the grinding, and thus, it is difficult to detect the abnormal status of the grinding and judge the sharpness of the grinding wheel. In the conventional machine control gage system, the abnormal status of the grinding is often missed. Moreover, it requires a great deal of skill to determine when the grinding wheel should be dressed.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the present invention to provide a machine control gage system that can easily detect the abnormal status of the grinding and judge the sharpness of the grinding wheel.
To achieve the above-mentioned object, the present invention is directed to a machine control gage system, comprising: a measuring device that detects changes in the size of a workpiece ground by a machine tool, and outputs electric signals representing the changes in the size of the workpiece; a controller that monitors the changes in the size of the workpiece in accordance with the electric signals outputted from the measuring device, and outputs a signal to control the machine tool when the workpiece reaches a predetermined size; and a display that displays a graph showing a record of the changes in the size of the workpiece in accordance with the electric signals outputted from the measuring device.
According to the present invention, the record of the changes in the size of the workpiece during the grinding is graphed on the display. It is therefore possible to know that there is an abrupt change or no change in the size of the workpiece during the grinding only by looking at the graph. Thus, the sharpness of the grinding wheel can be judged easily and the dressing time of the grinding wheel can be determined without a great deal of skill.
According to the present invention, the machine control gage system further comprises a first abnormality detector that monitors the changes in the size of the workpiece in accordance with the electric signals outputted from the measuring device, and outputs a first abnormality detection signal when a time elapsed for a predetermined change in the size of the workpiece is out of a predetermined allowable range.
The defects result from the decrease in the sharpness of the grinding wheel. The grinding time of the grinding wheel with the dull cutting edge is beyond the predetermined allowable range until the workpiece is ground by a certain feed amount, since the grinding wheel does not grind the workpiece and the workpiece is elastically deformed. With the dull cutting edge, the grinding feed amount is decreased during the fine grinding and the spark-out grinding, and consequently, the workpiece is ground by the elastic return force thereof, and the grinding amount is beyond the allowable range. To address these problems, the time required for a predetermined change in size is monitored in the present invention, so that whether the dressing for the grinding wheel is required can be determined automatically.
According to the present invention, the machine control gage system further comprises a second abnormality detector that monitors an amplitude of oscillatory components of the electric signals outputted from the measuring device, and outputs a second abnormality detection signal when the amplitude exceeds a predetermined allowable value. The defects resulting from the eccentricity of the workpiece, the inferior grinding wheel, the abrasive grains, the chips, the chatter, etc. can be detected by monitoring the amplitude of the electric signals outputted from the measuring device.
According to the present invention, the display displays a graph showing a record of the changes in the size of the workpiece in normal machining. Therefore, the sharpness of the grinding wheel can easily be checked in detail since the record of sizes in the normal machining and the record of sizes in the resent machining are displayed on the display.
REFERENCES:
patent: 4471580 (1984-09-01), Robillard
patent: 4802311 (1989-02-01), Scheder et al.
patent: 5103596 (1992-04-01), Fujii et al.
patent: 5148637 (1992-09-01), Byron
patent: 5741172 (1998-04-01), Trionfetti et al.
patent: 5876265 (1999-03-01), Kojima
patent: 6-106453 (1994-04-01), None
patent: 6-335843 (1994-12-01), None
patent: 11-10482 (1999-01-01), None
Kobayashi Hiroyuki
Shibata Haruo
Morgan Eileen P.
Oliff & Berridg,e PLC
Tokyo Seimitsu Co. Ltd.
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