JP4825051B2 - Laser processing apparatus and laser processing method - Google Patents

Description

  The present invention relates to a laser processing apparatus and a laser processing method, and in particular, a laser capable of controlling the output of a processing laser beam based on not only the temperature at the processing location of the processing object but also the transmittance and absorption rate of the processing object. It relates to processing technology.

As shown in FIG. 4A, a laser beam is applied to the surface of the laser transmissive resin material 52 in a state in which the resin material 50 having laser absorption and the resin material 52 having laser transmission are laminated. When irradiated, the laser beam passes through the laser transmitting resin material 52 and reaches the laser absorbing resin material 50.
As a result, first, the surface of the laser-absorbing resin material 50 is heated and melted, and the opposing surface of the laser-transmitting resin material 52 is melted by the conduction heat, and as shown in FIG. The opposing surfaces of the resin materials 50 and 52 are fused to each other.

In this laser resin welding, the processing quality may become unstable due to non-uniformity of the initial temperature of the workpiece and heat conduction from the already processed area that occurs as the processing progresses. It is said that temperature control of the processing area is extremely important.
For example, in Patent Document 1, the emitted light from the processing region is decomposed into different wavelengths, the surface temperature of the workpiece is obtained based on the intensity ratio between the wavelengths, and the surface temperature is controlled to a predetermined temperature based on this. Technology is disclosed.
Patent Document 2 discloses a technique for measuring a temperature in a temperature measurement region set at the rear of a laser irradiation position during laser processing and determining a welding failure when the temperature deviates from a predetermined temperature range.
JP-A-5-261576 JP-A-2005-7415

Certainly, it is reasonable to determine the quality of laser welding by measuring the temperature around the machining location.
However, the temperature at which a good bonding state is obtained varies greatly depending on the characteristics of the workpiece, particularly the laser absorption rate (laser absorbing resin) and transmittance (laser transmitting resin). No solution for this problem is disclosed in each of these patent documents.
For this reason, at present, the temperature range that is a criterion for determining the quality of the processing quality is, in the end, set based on empirical rules.

  The present invention has been devised in order to solve the above-described problems of the conventional laser processing method, and a temperature range serving as a reference for determining quality of processing quality can be calculated for each processing object. The purpose is to provide technology.

  In order to achieve the above object, a laser processing apparatus according to claim 1 includes a first laser oscillator that emits a processing laser beam, a second laser oscillator that emits a reference laser beam, and each laser beam. An optical system that guides the workpiece to the workpiece, a reflection intensity sensor that detects the intensity of the reference laser beam reflected from the surface of the workpiece, and infrared rays of a predetermined wavelength emitted from the machining location of the workpiece. A first infrared sensor for detecting, a second infrared sensor for detecting an infrared ray having a wavelength different from the above emitted from a processing portion of the workpiece, and a control device, the control device including the reflection intensity Based on the output from the sensor, the means for calculating the transmittance or absorption rate of the workpiece, and the output of the workpiece based on the outputs from the first infrared sensor and the second infrared sensor. Means for calculating a degree, the transmissivity or absorption rate of the workpiece, on the basis of the temperature of the workpiece is characterized in that a means for adjusting the output of the processing laser beam.

  According to a second aspect of the present invention, there is provided a laser processing method comprising: irradiating a surface of a workpiece with a reference laser beam; and the intensity of the reference laser beam reflected from the surface of the workpiece to be reflected intensity. The step of detecting by the sensor, the step of calculating the transmittance or absorption rate of the workpiece based on the output from the reflection intensity sensor, and the laser processing based on the transmittance or absorption rate of the workpiece. A step of calculating an allowable temperature range serving as a criterion for pass / fail judgment, a step of irradiating the surface of the processing object with a laser beam for processing, and an infrared ray of a predetermined wavelength emitted from a processing portion of the processing object, A step of detecting via the first infrared sensor, a step of detecting an infrared ray of a wavelength different from the above emitted from the processing location of the object to be processed via the second infrared sensor, and the first red color The step of calculating the temperature of the processing object based on the outputs from the line sensor and the second infrared sensor, the temperature of the processing object is compared with the allowable temperature range, and the temperature of the processing object is within the allowable temperature range. The process is characterized by comprising the step of adjusting the output of the laser beam for processing when the deviation is made.

In the laser processing apparatus and the laser processing method according to the present invention, the intensity of the reference laser beam reflected on the surface of the processing object is detected, and the laser transmittance (laser of the processing object is determined based on the reflection intensity. (In the case of a transparent resin material) or an absorption rate (in the case of a laser-absorbing resin material), and calculating a temperature range optimum for laser processing of the workpiece based on the transmittance or the absorption rate it can.
The quality of the processing can be determined based on this temperature range, and as a result, the processing quality of laser resin welding can be homogenized and stabilized.

  FIG. 1 is a schematic diagram showing a basic configuration of a laser processing apparatus 10 according to the present invention. A personal computer 12 as a control apparatus, a fiber laser oscillator 14 for emitting a processing laser beam, and a reference laser beam are shown. An outgoing infrared laser oscillator 16, a first infrared light receiving sensor 18, a second infrared light receiving sensor 20, a third infrared light receiving sensor 22, a first wavelength selection mirror (dichroic mirror) 24, 2 wavelength selection mirrors (dichroic mirrors) 26, a first condenser lens 28, a second condenser lens 30, a third condenser lens 32, and a fourth condenser lens 34. ing.

A fiber laser oscillator 14, an infrared laser oscillator 16, a first infrared light receiving sensor 18, a second infrared light receiving sensor 20, and a third infrared light receiving sensor 22 are connected to the personal computer 12 via an interface board (not shown). ing.
The personal computer 12 is set up with an OS and a dedicated application program, and executes various controls (details will be described later).

The first wavelength selection mirror 24 has a characteristic of transmitting infrared light having a preset wavelength (for example, 800 to 1,200 nm) and reflecting other infrared light.
Further, the second wavelength selection mirror 26 has a characteristic of reflecting a laser beam having a wavelength of 1,070 nm emitted from the fiber laser oscillator 14 and transmitting other infrared rays.

On the processing stage 36, a processing object 38 is placed.
The object to be processed 38 is formed of a laminate of the laser-absorbing resin material 42 and the laser-transmitting resin material 40.

Next, a method of using the laser processing apparatus 10 will be described with reference to the flowchart of FIG.
First, the operator operates the personal computer 12 to emit a reference laser beam A from the infrared laser oscillator 16 (S10).
The laser beam A is reflected by the first wavelength selection mirror 24, passes through the second wavelength selection mirror 26, reaches the first condenser lens 28, and forms an image on the surface of the workpiece 38.

Then, the laser beam specularly reflected by the surface of the workpiece 38 passes through the second wavelength selection mirror 26 and reaches the first wavelength selection mirror 24, and the laser beam reflected there reaches the fourth condensing. The light enters the third infrared light receiving sensor 21 via the lens 34.
Further, the laser beam diffusely reflected on the surface of the workpiece 38 passes through the second wavelength selection mirror 26 and reaches the first wavelength selection mirror 24, and the laser beam reflected there reaches the third condensing. The light enters the second infrared light receiving sensor 20 via the lens 32.
As a result, a signal indicating the reflection intensity is output from the second light receiving sensor 20 and the third light receiving sensor 22 and is input to the personal computer 12.

Upon receiving this, the CPU of the personal computer 12 (S12) calculates the laser absorption rate of the workpiece 38 based on the regular reflection intensity and the diffuse reflection intensity of the reference laser beam (S14).
For example, when the output intensity from the infrared laser oscillator 16 is 100%, if the regular reflection intensity and the diffuse reflection intensity are 30%, the absorption rate of the laser-absorbing resin material 42 is 70%.

Next, the CPU of the personal computer 12 substitutes this absorption rate into a predetermined algorithm, and calculates the optimum temperature range for processing the processing object 38 (S16). This optimum temperature range is set in the memory of the personal computer 12.
Next, when the operator commands the personal computer 12 to execute processing, a laser beam B for processing is emitted from the output portion of the fiber laser oscillator 14 as shown in FIG.
The laser beam B is reflected by the second wavelength selection mirror 26 and reaches the first condenser lens 28 and forms an image on the surface of the workpiece 38.
The laser beam B for processing passes through the laser-transmitting resin material 40 and reaches the laser-absorbing resin material 42, and heats the surface thereof.
The opposing surfaces of the laser-transmitting resin material 40 are melted by the conduction heat accompanying the heating and melting of the laser-absorbing resin material 42. As a result, the two resin materials are joined.

The heat generated by the laser resin welding causes infrared rays to be emitted from the surface of the workpiece 38. The infrared rays pass through the second wavelength selection mirror 26 and pass through the first wavelength selection mirror 24. Reach.
The infrared ray C having a specific wavelength passes through the first wavelength selection mirror 24, reaches the second condenser lens 30, and enters the first infrared light receiving sensor 18.
The remaining infrared ray D is reflected by the first wavelength selection mirror 24 and enters the second infrared light receiving sensor 20 via the third condenser lens 32.

The CPU of the personal computer 12 that has received data from the first infrared light receiving sensor 18 and the second infrared light receiving sensor 20 calculates the temperature at the surface of the workpiece 38 based on the intensity of each wavelength (S20).
Next, the CPU of the personal computer 12 determines whether or not the calculated temperature is within the optimum temperature range set on the memory (S22).

Here, when the calculated surface temperature of the workpiece 38 is within the optimum temperature range, the processing is continued as it is.
On the other hand, when the surface temperature of the workpiece 38 is outside the optimum temperature range, the CPU of the personal computer adjusts the output of the fiber laser oscillator 14 according to the degree of deviation (S24), and the surface temperature is within the optimum temperature range. Control to fit within.
Since the monitoring of the surface temperature of the workpiece 38 and the output control of the fiber laser oscillator 14 are continued in real time until the machining is completed (S26), the surface temperature of the workpiece 38 is always maintained within the optimum temperature range. It becomes possible to do.

  In the above, an example in which the present invention is applied to laser resin welding has been described. However, the scope of application of the present invention is not limited to this, and can be applied to other laser processing (for example, soldering).

It is a schematic diagram which shows the basic composition of the laser processing apparatus which concerns on this invention. It is a flowchart which shows the control procedure of this laser processing apparatus. It is a schematic diagram which shows the basic composition of the laser processing apparatus which concerns on this invention. It is sectional drawing which shows a mode that a laser absorptive resin material and a laser transparent resin material are joined using a laser beam.

Explanation of symbols

10 Laser processing equipment
12 PC
14 Fiber laser oscillator
16 Infrared laser oscillator
18 First infrared sensor
20 Second infrared sensor
22 Third infrared sensor
24 First wavelength selective mirror
26 Second wavelength selective mirror
28 First condenser lens
30 Second condenser lens
32 Third condenser lens
34 Fourth condenser lens
36 Machining stage
38 Workpiece
40 Laser transmissive resin material
42 Laser-absorbing resin material

Claims (2)

A first laser oscillator for emitting a processing laser beam;
A second laser oscillator for emitting a reference laser beam;
An optical system for guiding each laser beam to a workpiece;
A reflection intensity sensor for detecting the intensity of the reference laser beam reflected by the surface of the workpiece;
A first infrared sensor for detecting infrared rays of a predetermined wavelength emitted from a processing location of the processing object;
A second infrared sensor for detecting infrared rays having a wavelength different from the above, emitted from the processing location of the processing object;
A control device,
The control device calculates a transmittance or absorptance of the workpiece based on the output from the reflection intensity sensor;
Means for calculating a temperature of the object to be processed based on outputs from the first infrared sensor and the second infrared sensor;
A laser processing apparatus comprising: means for adjusting the output of the processing laser beam based on the transmittance or absorption rate of the processing object and the temperature of the processing object. Irradiating the surface of the workpiece with a reference laser beam;
A step of detecting the intensity of the reference laser beam reflected by the surface of the workpiece with a reflection intensity sensor;
Based on the output from the reflection intensity sensor, calculating the transmittance or absorption rate of the workpiece,
Based on the transmittance or absorptance of the object to be processed, a step of calculating an allowable temperature range that is a criterion for determining the quality of laser processing
Irradiating the surface of the object to be processed with a laser beam for processing;
Detecting infrared rays of a predetermined wavelength radiated from a processing location of the processing object via a first infrared sensor;
A step of detecting an infrared ray having a wavelength different from the above, emitted from a machining portion of the workpiece, via a second infrared sensor;
Calculating the temperature of the workpiece based on outputs from the first infrared sensor and the second infrared sensor;
Comparing the temperature of the object to be processed with the allowable temperature range, and when the temperature of the object to be processed is out of the allowable temperature range, the process includes a step of adjusting the output of the laser beam for processing. Laser processing method.

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