JPS6120685A - Work inspection method - Google Patents

Abstract

PURPOSE:To prevent the damages of a photodetector by a retreat as well as to confirm the piercing completion by positioning a retreating photodetector beneath the material to be worked after the piercing with a laser beam irradiation of the material to be worked and by detecting the complete passing with the laser beam for maeasurement. CONSTITUTION:A piercing with irradiation 18 is performed with a laser beam 5 on the prescribed position of the material 9 to be worked of a chuck jig supporting cylinder shape. A shape detector 10 is advanced with driving a motor 13 after the prescribed time and with detecting the laser beam 5 for measurement of a laser nozzle 1 the completion of the piercing 18 is detected. The conventional incomplete piercing is surely prevented. The shape detector 10 is retreated during the laser beam piercing and the adhesion of scattering matters is prevented by an inert gas 17 for cleaning the detecting face at the position beneath the piersing and there is no damage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a machining inspection method for detecting a machined part that has been drilled using a laser beam.

[Technical background of the invention and its problems]

When processing a workpiece using a laser beam, the processing state is inspected to determine whether the processing state is good or bad.

Conventionally, such an inspection as shown in FIG. 2 or 3 has been used. In other words, the second factor is that when the laser beam a is irradiated onto the workpiece, the processed part emitted from the processing point of the workpiece is captured by the microphone C, and the processed part that has a correlation with the amount of melting is detected. The processing state is detected from the size of The machining state is detected from the magnitude of vibration, which is correlated with the amount of molten metal. In Figures 2 and 3, e is a laser oscillator, f is a cart for moving the workpiece at a predetermined speed, q is an amplifier, h is an indicator, i is a filter, and j is a light condenser. It's a lens.

However, according to such a machining inspection method, although the machining state can certainly be determined from the molten state of the workpiece, there is a problem in that it is not possible to detect the state in which the drilling process has been completed.

In other words, it is possible to detect that a hole has been drilled in the workpiece from the machining area that correlates with the amount of melting or from the magnitude of vibration, but this hole is detected when the machining is completed, and even immediately after the machining is completed. There is a risk that it will be blocked again by melted material or flying debris during processing. In particular, this hole clogging phenomenon tends to occur when drilling deep holes with minute diameters such as Φ0.1# to Φ0.3s. The problem is that a hole is incorrectly detected even though it is closed.

In view of this, an inspection method as shown in Japanese Unexamined Patent Publication No. 57-226335 has been proposed. In this method, a reflective mirror is fixedly installed at the rear of the workpiece directly below the machining point, and a measuring laser beam is irradiated through the reflective mirror to the machining point where the hole has been drilled. This is an inspection method in which a measuring laser beam passing through an aperture at a processing point is detected by a light receiving element to detect a processed part.

According to this, although it is possible to detect that the hole has been machined without error, on the other hand, because the reflecting mirror is fixedly installed directly below the processing point,
In addition to the drawback that the reflective mirror is easily soiled by flying debris caused by the drilling process, it cannot withstand long-term use.
It also requires a dichroic mirror to branch the measurement laser beam from the optical path of the laser beam for processing and guide it to the light receiving element, as well as a mechanism to drive the dichroic mirror, resulting in mechanically complex problems. There is a need for something that can improve these points as well.

[Purpose of the invention]

This invention has been made in view of the above-mentioned circumstances, and its purpose is to directly receive measurement laser light from a processing part that has been drilled using a laser beam without being affected by flying objects. The object of the present invention is to provide a processing inspection method that can be detected using an element.

[Summary of the Invention] That is, the present invention irradiates the workpiece with a processing laser beam through an optical path to finish drilling a φ hole in the workpiece, and then performs the drilling process at the rear of the workpiece. , a light-receiving element that can move forward and backward, which had been previously retracted from the axis of the machining point, is placed directly below the machining point of the workpiece, and the light-receiving element irradiates the machining point toward the machining point. By detecting the measurement laser beam that has passed through the aperture and detecting the processed part, the light receiving element moves forward and backward from directly below the processing point, and the measurement laser beam is irradiated coaxially with the optical path to avoid the effects of flying objects. At the same time, it attempts to detect the machined part through direct detection of the measurement laser beam.

[Embodiments of the invention]

The present invention will be explained below based on an embodiment shown in FIG. FIG. 1 shows a processing inspection apparatus to which the method of the present invention is applied, and 1 is a lens holder equipped with a condensing lens 2 inside. The incident side of the condenser lens 2 is optically connected to a laser oscillator (not shown), and the lens holder 2
The focused laser beam 5 for processing can be emitted from the hole 4 formed at the tip of the lens holder 1, with the inside of the lens holder 1 facing the exit side of the optical path 3. The laser oscillator (not shown) also includes an auxiliary laser beam (usually He-N
An oscillator (not shown) that oscillates a laser beam (e laser beam) is attached, and this auxiliary laser beam can be used as the measuring laser beam 5a to emit the same through the optical path 3 to the hole 4. ing. When the drilling process is completed under the control of a control unit (not shown) of a laser oscillator, the measurement laser beam 5a stops oscillating and starts the measurement laser beam 5a. Instead, it is made to oscillate. Note that 6 is an assist gas inlet portion for sending the assist gas 7 toward the hole 4 through the portion below the condenser lens 2.

On the other hand, 8 is a cylindrical workpiece supported by a chuck jig 9. This workpiece 8 is placed directly below the hole 4 in a partial state. Further, 10 is a shape detection element as a light receiving element arranged inside the workpiece 8 at the rear of the workpiece 8, and 11 is a shape detection element 11 that moves the shape detection element 10 back and forth along the axial direction of the workpiece 8. It is a forward and backward mechanism for moving.

The advancing/retracting mechanism 11 includes an element holder 12 that is provided in the workpiece 8 so as to be able to move forward and backward along the axis of the workpiece 8, and an element holder 10 is provided on the base side of the element holder 12 that protrudes from the end of the workpiece 8. It is constructed by providing a drive source 13 for driving the motor forward and backward. The shape detection element 10 is attached to the tip of the element holder 12 so that its light-receiving surface faces the hole 4 side, and a circuit 14 for receiving the signal from the shape detection element 10 is attached to the base of the element holder 12. It will be done. In addition, drive source 1
3 and the circuit 14 of the shape detection element 10 includes an amplifier 15.
The shape detection element 10 is normally placed in a retracted state with respect to the axis of the machining point of the workpiece 8, while the ink to face part 16 is connected in sequence to form a hole. When a termination signal indicating that the laser oscillation time has elapsed is input, the shape detection element 10 is advanced and placed at a location directly below the processing point of the workpiece 8. In addition, 17 is a gas supply path for flowing a clean gas such as a clean inert gas or clean air toward the light receiving surface of the shape detection element 10, and this is a gas supply path that is always connected to the shape detection element 10 during the drilling operation. The gas is sprayed onto the light receiving surface of the sensor.

Next, the method of the present invention will be explained using the processing inspection apparatus configured as described above.

First, a laser beam 5 for processing is oscillated from a laser oscillator (not shown). Assist gas 7 is introduced from assist gas inlet 6 in conjunction with this oscillation. At this time, the shape detection element 10 is disposed at a point away from the axis of the processing point of the workpiece 8. On the other hand, the oscillated processing laser beam 5 passes through the optical path 3 and the condensing lens 2 to the workpiece 8.
The peripheral side wall of the workpiece 8 is melted by the laser beam and a hole is drilled.

゛ Here, there is a concern that the shape detection element 10 may be affected by flying objects during the drilling process, but the shape detection element 10
Since it is arranged far away from the processing point of the workpiece 8, it is possible to prevent flying objects from adhering to the light-receiving surface of the shape detection element 10. Moreover, since clean inert gas or clean air is blown toward the light receiving surface from the gas supply path 17 during the drilling process, there is no fear of dust or scattered matter adhering to the light receiving surface.

On the other hand, the drilling process is performed by setting the time necessary for drilling in the control section of a laser oscillator (not shown) in advance, and when the drilling process is completed, the oscillation of the processing laser beam 5 is stopped. A completion signal indicating that the processing has been completed is output to the interface section 16 and the control section of the laser oscillator (not shown), respectively. Along with this, a laser oscillator (not shown) oscillates a measuring laser beam 5a instead of the processing laser beam 5 that performs processing, leaving the optical path 3 used for processing as it is and coaxial with and the same as the optical path 3. The measuring laser beam 5a is irradiated from the direction toward the machined hole 18 (machining point) of the workpiece 8, and when the interface part 16 receives the end signal, the drive source 13 is activated. During the drilling process, the shape detecting element 10 that had been retracted is moved forward by the drive of the advancing/retracting mechanism 11 so as to be placed directly under the hole 18 (machining point).

However, depending on the presence or absence of the measurement laser beam 5a that enters the shape detecting element 10 through the hole 18 that has been machined, if the hole drilling process has been carried out smoothly until the completion of the hole 18, the hole 1
The measurement laser beam 5a passing through the opening 8 is detected by the shape detection element 10 to confirm that the hole has been properly machined and to recognize the shape of the hole. Then, a signal indicating that the drilling process is completed is output to a control unit (not shown) that rotationally drives the chuck oil 7, and the workpiece 8 is rotated so that the next processing point faces the optical path 3. let

Furthermore, if the machined hole 18 is blocked by melted material or scattered matter immediately after the completion of processing, the blockage may occur because there is no measuring laser beam 5a passing through the opening of the hole 18. The state is detected by the shape detection element 10 (a state in which no signal is output from the shape detection element 10). Then, a signal to this effect is transmitted to a control section (not shown) of the laser oscillator, and the drilling process is performed again.

However, it is now possible to directly detect the completion of drilling from the measuring laser beam 5a, and it is now possible to completely eliminate the need for a dichroic mirror and the mechanism that drives the dichroic mirror, which was previously required. It becomes possible to detect the portion where the hole has been drilled without the need for the hole-drilling process.

In this way, it is possible to detect whether or not the hole machining has been completed, such as in the machining part where the hole clogging phenomenon is likely to occur, such as during deep hole machining, with a minute hole diameter such as 00.1 s to Φ0.3 mm. By employing the method of the present invention, it is possible to detect processing parts that are considered impossible with a simple configuration and without being affected by flying objects.

In the above-mentioned embodiment, the method of the present invention was applied to drilling a hole in a cylindrical workpiece, but of course, detection of drilling in a plate-shaped workpiece is also possible when the rear of the workpiece is detected. The method of the present invention can be applied by arranging the shape detection element so that it can move forward and backward.

Furthermore, in the embodiment described above, the measurement laser beam is emitted after the processing laser beam has stopped emitting, but of course the measurement laser beam is emitted at the same time as the processing laser beam. It goes without saying that a device that can be used for irradiation may also be used.

[Effects of the Invention λ As explained above, according to the present invention, a measurement laser beam can be used without requiring a dichroic mirror or a mechanism for driving the dichroic mirror, which was conventionally required. In addition to being able to detect the completed machining part by direct detection of the machining part, the light receiving element is placed directly below the machining point only when the machining part is detected, and the light receiving element is evacuated from the machining point during drilling. By moving the light-receiving element as described above, it becomes possible to avoid interference of scattered objects with the light-receiving element, and it is possible to easily and accurately detect the processed part while preventing the influence of the scattered objects.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of a machining inspection method to which the method of the present invention is applied, and FIGS. 2 and 3 are side views showing different conventional machining inspection methods. 3... Optical path, 5... Laser light for processing, 5a... Laser light for measurement, 8... Workpiece, 1o... Shape detection element (light receiving element), 11... Shin'A organization. Applicant's agent Patent attorney Takehiko Suzue Figure 1

Claims (1)

[Claims] After completing the drilling process on the workpiece by irradiating the processing laser beam to the workpiece through the optical path, the laser beam is evacuated from the axis of the processing point in advance during the drilling process at the rear of the workpiece. A light-receiving element that can move forward and backward is placed at a location directly below the processing point of the workpiece, and the light-receiving element detects a measurement laser beam that is irradiated toward the processing point and passes through the aperture of the processing point. A processing inspection method characterized by detecting a processed part.