JP2000275017A - Judgment method and judging apparatus for distortion amount - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inline type judgment method for a distortion amount whereby the distortion amount can be judged at an equal station to a station for laser processing. SOLUTION: The method is applied to laser processing whereby a laser light is irradiated to a work to apply a distortion. An irradiation pattern of the laser light at the work is picked up by a CCD camera 32 on an equal axis to the laser light. The obtained image is processed by an image-processing apparatus 35 to obtain data related to light and dark. A distortion amount is judged with the use of the obtained data with reference to a table indicating a preliminarily obtained correspondence of the distortion amount and data related to light and dark.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for determining the amount of distortion of a workpiece, which is applied to laser processing for applying distortion by irradiating a workpiece with laser light.

[0002]

2. Description of the Related Art Recently, a laser processing apparatus for irradiating a workpiece with a laser beam to apply distortion has been proposed (for example, Japanese Patent Application No. 10-103920). This laser processing device
The irradiated portion is locally heated by irradiating one main surface of the plate-shaped work with the laser beam, and the tensile (shrinkage) stress accompanying the rapid cooling after the local heating is left in the irradiated portion, and The workpiece is deformed so that the main surface on the side including the concave shape becomes concave.

[0003]

In the main laser processing, when a distortion is generated by irradiating the surface of the work with a laser beam, it is necessary to determine the amount of the distortion. In this case, it is not preferable that the workpiece is transported to another location after processing and the amount of distortion is determined because the number of steps and locations for determining the amount of distortion increases.

An object of the present invention is to provide an in-line type strain amount discriminating method capable of discriminating a strain amount at the same station as laser processing.

Another object of the present invention is to provide a distortion amount discriminating apparatus suitable for the above-described distortion amount discriminating method.

[0006]

The method for determining the amount of distortion according to the present invention is applied to laser processing for applying a laser beam to a workpiece to apply distortion, and the irradiation pattern of the laser beam on the workpiece is determined by the laser beam. An image is taken by an imaging system on the same axis as the image, and the obtained image is subjected to image processing to obtain data relating to shading, and the acquired data is used to indicate a correspondence relationship between a previously obtained distortion amount and shading data. The distortion amount is determined with reference to a table.

[0007] A distortion amount determining apparatus according to the present invention is applied to laser processing for applying distortion by irradiating a laser beam to a work, and is an apparatus for determining the amount of distortion of the work in-line. An imaging system that captures an irradiation pattern coaxially with the laser light, an image processing device that performs image processing on an image obtained by the imaging system to obtain data regarding shading, and is obtained in advance using the obtained data. A discriminating means for discriminating the amount of distortion by referring to a table indicating a correspondence relationship between the amount of distortion and data of light and shade.

[0008] The discriminating means receives the data indicating the shading from the image processing apparatus, and performs shading level discrimination of the shading of the irradiation pattern. And a comparing means having a table showing a correspondence relationship between the gray level and the gray level.

The table stores the correspondence between the amount of distortion and the upper and lower limit values of the grayscale data corresponding to the distortion amount, so that the comparing means can determine whether the acquired grayscale data is the upper limit or lower limit. Whether the distortion amount is good or not can be determined based on whether the value falls within the range of the value and the lower limit value.

[0010]

Embodiments of the present invention will be described below. FIG. 2 shows a surface photograph including an irradiation pattern (here, a rectangular shape) when the ceramic is irradiated with YAG laser light, and FIG. 3 shows the relationship between the energy intensity of YAG laser light and the amount of distortion. Of course, the relationship between the energy intensity and the amount of strain of the YAG laser beam changes depending on the material of the work, but the irradiation pattern becomes clearer as the irradiation energy increases. Similarly, the distortion amount increases as the irradiation energy increases. That is, even if the material is changed, the amount of distortion increases as the irradiation pattern becomes clearer. Using this relationship, the present embodiment is characterized in that the distortion amount is determined using the image of the irradiation pattern.

FIG. 1 schematically shows a laser processing apparatus and a distortion discriminating apparatus. The laser light emitted from the YAG laser device 10 is turned 90 degrees by the YAG total reflection mirror 11,
The work (for example, ceramics) 13 is irradiated through the processing lens 12. This optical system performs distortion processing.

The distortion amount discriminating apparatus includes an illumination system 20 and an image processing system 30. The illumination system 20 converts the light emitted from the illumination fiber 21 into a lens 22, a half mirror 23, and the processed lens 1.
Irradiation is performed on the work surface through the surface 2. The YAG total reflection mirror 11 totally reflects only the YAG laser beam and transmits visible light.

The image processing system 30 takes in the state of the workpiece surface with the CCD camera 32 via the processing lens 12, the YAG total reflection mirror 11, the half mirror 23, and the lens 31. Also in this case, the YAG total reflection mirror 11 transmits visible light. Since the half mirror 23 is a half mirror of visible light, 50% of the light is transmitted. CCD camera 3
The image signal captured in 2 is amplified through an amplifier 33 and sent to a monitor 34 and an image processing device 35.

The monitor 34 displays an image of the work surface including the laser beam irradiation pattern. On the other hand, the image processing device 35 processes the image signal and outputs data indicating shading in the irradiation pattern. As the data indicating the shading, for example, a total value of luminance values in the entire irradiation pattern or an average value of luminance values in the entire irradiation pattern is used.

The gray level discriminating unit 36 receives the data indicating the gray level from the image processing unit 35, and classifies the levels of the irradiation pattern. The comparator 37 stores a table indicating the correspondence between the amount of distortion measured by actual shooting and the density level of the irradiation pattern in advance. In particular, the upper and lower limits of the gray level are stored for each distortion amount. Since the amount of distortion to be applied to the work 13 is known in advance, the comparator 37 uses the upper limit value and the lower limit value of the gray level corresponding to the distortion amount,
It is compared whether or not the shade level classified by the shade level discriminating device 36 falls within the range between the upper limit value and the lower limit value, and if so, it is judged as a good product, and if not, it is judged as a defective product.

The image processing device 35 is configured to start image processing upon receiving a laser irradiation completion signal from the YAG laser device 10, so that the quality of each work is determined. Further, as described above, the correspondence between the amount of distortion and the density level of the irradiation pattern changes according to the material of the work, and therefore, the comparator 37 determines the amount of distortion and the density of the irradiation pattern in accordance with the type of the material. It is needless to say that a table indicating the correspondence relationship with the level is prepared.

In the above description, YA is used in laser processing.
Although the case where a G laser device is used has been described, the present invention is applicable to a laser processing device using any laser oscillator as long as the type of the laser processing device imparts distortion.

[0018]

According to the present invention, since the strain amount can be determined at the same station as the laser processing by using an in-line type, the number of steps and locations for determining the strain amount can be reduced, and real-time in-line management can be performed. Will be possible.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a laser processing apparatus to which the present invention is applied and a distortion amount determining apparatus according to the present invention.

FIG. 2 is a diagram showing an irradiation pattern surface micrograph when a ceramic is irradiated with a YAG laser beam.

FIG. 3 is a diagram showing a relationship between the energy intensity of YAG laser light and the amount of distortion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 Processing lens 20 Illumination system 21 Illumination optical fiber 22, 31 Lens 23 Half mirror 30 Image processing system 32 CCD camera 33 Amplifier 34 Monitor 35 Image processing device 36 Shade level discrimination device 37 Comparator

Continued on front page F term (reference) 2F065 AA65 BB01 CC00 DD06 FF42 HH13 JJ03 JJ09 JJ26 LL00 LL02 LL04 LL20 QQ03 QQ23 QQ24 QQ25 QQ27 QQ42 RR09 SS02 SS13 4E068 AH00 CA17 CB09 CC00 CC02

Claims (5)

[Claims] The present invention is applied to laser processing in which a workpiece is irradiated with laser light to give a distortion, and an irradiation pattern of the laser light on the workpiece is imaged coaxially with the laser light by an imaging system. Processing, obtaining data relating to shading, and using the obtained data, referring to a table indicating a correspondence relationship between the previously calculated distortion amount and shading data to determine the distortion amount. Amount determination method. 2. The distortion amount determining method according to claim 1, wherein
The table stores the correspondence between the amount of distortion and the upper and lower limit values of the corresponding grayscale data, and the acquired grayscale data falls within the range of the upper and lower limit values. A distortion amount discriminating method characterized by determining whether or not the distortion amount is good or not. 3. An apparatus which is applied to laser processing for irradiating a laser beam to a workpiece to give a distortion, and which determines an amount of distortion of the workpiece in-line, wherein an irradiation pattern of the laser beam on the workpiece is determined by the laser beam. An imaging system that performs imaging on the same axis as the above, an image processing device that performs image processing on an image obtained by the imaging system to obtain data relating to shading, and a distortion amount and shading that are obtained in advance using the obtained data. A discriminating means for discriminating the amount of distortion with reference to a table indicating a correspondence relationship with the data. 4. The distortion amount discriminating apparatus according to claim 3,
The discriminating means receives the data indicating the shading from the image processing apparatus, and performs shading level discrimination for performing shading levels of the irradiation pattern, and the distortion amount and shading level of the irradiation pattern previously measured by actual irradiation. And a comparing means having a table indicating the correspondence between the two. 5. The distortion amount determining device according to claim 3, wherein
The table stores the correspondence between the amount of distortion and the upper limit value and lower limit value of the corresponding grayscale data, and the comparing means stores the obtained grayscale data in the upper limit value and the lower limit value. Wherein the quality of the distortion is determined based on whether the distortion is within the range.