Abstract The invention disclosed provides a device having means for emitting two beams of laser light in parallel and in contact respectively with an upper edge and a lower edge of a rotating cylindrical workpiece while under machining conditions such as in a lathe. The two laser beams hit the workpiece edges and then enter respective light receivers wherein diffraction images of the upper and the lower edges of the workpiece, which are sharpened by means of an optical filter, are defined on image planes formed with optical fibers. Intensity distributions of the diffraction images are converted into electric signals and processed in order to identify the diameter at the machining point of the workpiece. In case the difference between the detected diameter and a desired diameter exceeds a specified value of allowable error, a correction signal is transmitted from a provided means which causes a tool position controlling device to adjust the position of the tool, thus ensuring accurate turning of the workpiece within a specified tolerance while rotating in the course of machining.
A device for controlling dimensional accuracy in machining a cylindrical workpiece which device comprises in combination, a light source emitting laser beams which hit the upper and lower edges of the workpiece respectively, a pair of light receivers each disposed to receive diffracted rays from the upper and lower edges of the workpiece, said light receivers each consisting of an object lens unit, an optical filter excluding zero-order component of diffracted rays, and an image plane, said image plane having a plurality of optical fibers for receiving a diffracted image of the workpiece edge, means for converting intensity distribution of said diffracted image into electrical signals, and identifying the actual diameter of the workpiece being machined, means for comparing the actual diameter with a desired diameter of workpiece and means for transmitting a correctIon signal to a tool position controlling device of a machine tool when the deflection obtained by said comparison is greater than a specified dimensional tolerance.
Claim 2
Independent Claim
159 words
A device for controlling dimensional accuracy in machining a cylindrical workpiece which device comprises in combination, a light source emitting laser beams which hit the upper and lower edges of the workpiece respectively, a pair of light receivers each disposed to receive diffracted rays from the upper and lower edges of the workpiece, said light receivers each consisting of an object lens unit, an optical filter excluding zero-order component of diffracted rays, and an image plane, said image plane having a plurality of optical fibers for receiving a diffracted image of the workpiece edge, means for converting intensity distribution of said diffracted image into electrical signals, and identifying the actual diameter of the workpiece being machined, means for comparing the actual diameter with a desired diameter of workpiece and means for transmitting a correctIon signal to a tool position controlling device of a machine tool when the deflection obtained by said comparison is greater than a specified dimensional tolerance.
Claim 3
Dependent Claim
20 words
The device according to claim 1 wherein optical filters are provided on the respective focal points of the object lenses.
Claim 4
Dependent Claim
23 words
The device according to claim 1 wherein each optical filter has a transparent body with a light absorption spot at the center thereof.
Claim 5
Dependent Claim
17 words
The device according to claim 3 wherein the body is glass and said spot is black pigment.
Claim 6
Dependent Claim
16 words
The device according to claim 3 wherein the body is plastic and said spot is black.