Calibration thermometer, its manufacturing method, radiation thermometer calibration method, and laser soldering device

Abstract

To provide a thermometer for calibration with which it is possible to calibrate a radiation thermometer easily in a short time.SOLUTION: A temperature sensor 19 and a solder 20 for temperature measurement which is the object of the temperature measurement are accommodated inside a measurement chamber 17 which is formed on the top face of a body 16. The temperature sensor 19 consists of a thermocouple in which two different types of metal wires 19a, 19b are connected to each other, with the connection point constituting a temperature measurement portion 19c for measuring temperatures. The solder 20 for temperature measurement is bonded to the temperature measurement portion 19c, and an oxidation prevention glass 23 for preventing the oxidation of the solder 20 for temperature measurement is attached to an opening 17a on the top face of the measurement chamber 17, with the solder 20 for temperature measurement adhered tightly without gaps to the underside of the oxidation prevent glass 23.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a calibration thermometer for calibrating a radiation thermometer. , its manufacturing method, radiation thermometer calibration method, and laser soldering device It is related to. [Background technology]

[0002] For example, in the field of laser soldering, which uses a laser beam to solder electronic components to printed circuit boards, the temperature of the molten solder is measured with a radiation thermometer, and the temperature information is fed back to adjust the output of the laser beam. Therefore, the solder temperature measured by the radiation thermometer is directly linked to the output of the laser beam, which has a significant impact on the accuracy of the soldering. Therefore, it is important to regularly manage the measurement accuracy of the radiation thermometer and maintain constant measurement accuracy by performing necessary calibration.

[0003] The calibration of the radiation thermometer is usually performed using a blackbody furnace, as described in Patent Document 1, for example. When using a blackbody furnace in this way, the blackbody furnace needs to be installed in an appropriate position on the soldering device during calibration, but selecting the installation location and installing it are not easy, and after installation, it takes 30 minutes or more to heat the blackbody furnace to the required temperature. Therefore, if it becomes necessary to calibrate the radiation thermometer during the soldering process, the soldering must be interrupted for a long time, resulting in a decrease in production efficiency. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-81816 Summary of the Invention [Problem to be solved by the invention]

[0005] The technical object of the present invention is to provide a calibration thermometer that allows calibration of a radiation thermometer easily and quickly without using a blackbody furnace. , its manufacturing method, radiation thermometer calibration method, and laser soldering device The purpose is to provide [Means for solving the problem]

[0006] In order to solve the above problems, the calibration thermometer of the present invention comprises: A calibration thermometer for calibrating a radiation thermometer of a laser soldering device, Inside the measuring chamber formed on the top surface of the body, A temperature measuring solder to be measured and a temperature sensor to measure the temperature of the temperature measuring solder and the temperature sensor - The thermocouple is made by connecting two different metal wires to each other, with the connection point serving as a temperature measuring part for measuring temperature, and the temperature measuring solder is attached to the temperature measuring part, and an oxidation prevention glass is attached to the opening on the top surface of the measurement chamber to prevent oxidation of the temperature measuring solder. The laser beam output from the laser soldering device is irradiated onto the temperature measuring solder through the oxidation prevention glass, The temperature measuring solder is tightly adhered to the lower surface of the oxidation resistant glass without any gaps.

[0007] In the present invention, Preferably, a partition plate on which the temperature-sensing solder is placed is provided in the measurement chamber, and the lower surface of the oxidation-resistant glass and the upper surface of the partition plate are made of a material that is not wettable by the temperature-sensing solder. Also, a hole is formed in the partition plate at the location where the temperature-sensing solder is placed, and the temperature-sensing part of the temperature sensor is bonded to the bottom surface of the temperature-sensing solder through the hole.

[0008] According to the present invention, there is also provided a method for manufacturing the calibration thermometer, wherein the temperature measuring solder is bonded to the oxidation-resistant glass by ultrasonic soldering.

[0009] According to the present invention, there is also provided a method for calibrating the radiation thermometer using the calibration thermometer, , While the laser light is irradiated onto the temperature-measuring solder, the temperature of the temperature-measuring solder is measured by the temperature sensor, and the temperature of the temperature-measuring solder is also measured by the radiation thermometer, and the emissivity of the radiation thermometer is calibrated from the respective measured values ​​of the temperature sensor and the radiation thermometer.

[0010] Furthermore, according to the present invention, there is provided a laser soldering apparatus in which the calibration thermometer is disposed in the vicinity of a soldering area where a soldering portion is located. [Effects of the Invention]

[0011] The calibration thermometer of the present invention is installed in the vicinity of the soldering area where the printed circuit board is arranged in the soldering device, and when calibrating the radiation thermometer, the irradiation head irradiates the temperature measuring solder with laser light, and the temperature of the melted temperature measuring solder is measured by the temperature sensor of the calibration thermometer. -and a radiation thermometer, and the emissivity of the radiation thermometer is offset according to the emissivity offset amount calculated according to the temperature difference between the two. Therefore, the calibration of the radiation thermometer can be easily performed in a very short time (about 20-30 seconds) compared to when using a blackbody furnace. In addition, the output of the irradiated laser light can be as low as a few watts, so it consumes less power and is economical. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a front view of a laser soldering apparatus equipped with a calibration thermometer according to the present invention; [Figure 2] FIG. 2 is a plan view of FIG. [Figure 3] FIG. 1 is a perspective view of a calibration thermometer according to the present invention. [Figure 4] FIG. 4 is a central longitudinal cross-sectional view of FIG. 3. [Figure 5] FIG. 1 is a configuration diagram of a calibration system for a radiation thermometer. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of a calibration thermometer according to the present invention will be described in detail below with reference to the drawings. Figures 1 and 2 show an example of a laser soldering apparatus equipped with a calibration thermometer according to the present invention. The soldering apparatus 1 is a gantry-type soldering robot, and includes a board-shaped base 2, left and right support columns 3, 3 extending from the base 2, first guides 4a disposed at the upper ends of the left and right support columns 3, 3 so as to extend in the front-to-rear direction (Y direction) of the apparatus, a second guide 4b spanning between the left and right first guides 4a, 4a and displaceable in the front-to-rear direction along the first guide 4a, a slide member 5 displaceable in the left-to-right direction (X direction) along the second guide 4b, an irradiation head 6 supported by the slide member 5, a radiation thermometer 7 supported by the irradiation head 6 or the slide member 5, a table 8 on which a printed circuit board 9 to be soldered is placed, and a controller 10 for controlling the entire soldering apparatus 1. The irradiation head 6 is connected to a laser oscillator 12 through an optical fiber 11, and the laser oscillator 12 and the radiation thermometer 7 are connected to the controller 10 through electric cables 12a and 7a, respectively. The emissivity of the radiation thermometer 7 is set to that of tin, which is the main component of solder.

[0014] When the soldering device 1 is used to solder a soldering target placed in the soldering area 8a on the table 8 for placing a board, i.e., a printed circuit board 9 and an electronic component 13, the irradiation head 6 irradiates a laser beam L onto the soldering portion, and solder supplied from a solder supply nozzle (not shown) is melted to perform soldering. At this time, the temperature of the soldering portion, i.e., the temperature of the melted solder, is measured by the radiation thermometer 7, and the measurement result is fed back to the controller 10, and the laser oscillator 12 is controlled in accordance with the measurement result, thereby controlling the laser beam irradiated from the irradiation head 6. - The output of the laser light L is adjusted.

[0015] The radiation thermometer 7 has to be calibrated periodically to maintain its accuracy, since its measurement accuracy has a significant effect on the accuracy of soldering. solder In the soldering apparatus 1, a calibration thermometer 15 for calibrating the radiation thermometer 7 is installed near the soldering area 8a on the table 8.

[0016] 3 and 4, the calibration thermometer 15 has a square block-shaped body 16. The body 16 can be made of a non-metallic inorganic material such as fine ceramics that is heat-resistant and non-conductive.

[0017] A measurement chamber 17 consisting of a square recess is formed on the upper surface of the body 16, and a thin, narrow partition plate 18 is attached to the inside of the measurement chamber 17 so as to span between the left and right chamber walls. A temperature sensor is attached to the underside of the partition plate 18. - 19 is attached to the upper surface of the partition plate 18, and the temperature sensor - A temperature measuring solder 20 is placed in the measuring chamber 17, the temperature of which is measured by the temperature measuring device 19. However, the partition plate 18 may have a width approximately equal to the width of the measuring chamber 17, and may completely separate the measuring chamber 17 into upper and lower chambers.

[0018] the temperature sensor - Reference numeral 19 is a thermocouple in which two different metal wires 19a and 19b are connected to each other, and the connection point is a temperature measuring part 19c for measuring temperature. The temperature measuring part 19c is exposed on the upper surface side of the partition plate 18 through a hole 18a formed in the partition plate 18, and the temperature measuring solder 20 is attached to the temperature measuring part 19c by soldering. The member indicated by reference numeral 21 in the figure is the temperature sensor. - The connector is used to connect the lead wire 19d connected to the connector 19 to the controller 10 (see FIG. 2). The partition plate 18 is made of a material that is not wettable by solder, so even if the temperature-measuring solder 20 is heated and melted by laser light when calibrating the radiation thermometer 7 (see Figure 2), the melted temperature-measuring solder will not wet and spread over the partition plate 18.

[0019] A transparent, heat-resistant oxidation-resistant glass 23 is attached to the upper opening 17a of the measurement chamber 17 so as to cover the temperature-sensing solder 20 in order to prevent oxidation of the temperature-sensing solder 20 due to contact with the atmosphere, and the temperature-sensing solder 20 is tightly adhered to the underside of the oxidation-resistant glass 23 by ultrasonic soldering so that no gaps are formed between the temperature-sensing solder 20 and the oxidation-resistant glass 23. Because the surface of the oxidation-resistant glass 23 is not wettable by solder, even if the temperature-sensing solder 20 is heated and melted by laser light during calibration of the radiation thermometer 7, the temperature-sensing solder 20 will not wet and spread along the underside of the oxidation-resistant glass 23. The oxidation-resistant glass 23 may be airtightly attached to the opening 17a so as to isolate the measurement chamber 17 from the atmosphere.

[0020] When the radiation thermometer 7 is calibrated using the calibration thermometer 15, the following steps are performed: to In this state, the irradiation head 6 and the radiation thermometer 7 are displaced from the soldering position shown in the figure to a position (calibration position) where the calibration thermometer 15 is placed. This constitutes a calibration system 25 shown in Figure 5. This calibration system 25 is composed of the calibration thermometer 15, the irradiation head 6, the radiation thermometer 7, and the controller 10 into which a calibration program has been input.

[0021] The calibration of the radiation thermometer 7 by the calibration system 25 is carried out, for example, before the start of a soldering operation, as follows. 5, first, laser light L is irradiated from the irradiation head 6 onto the temperature-measuring solder 20 of the calibration thermometer 15 through an oxidation-resistant glass 23. At this time, the intensity (output) of the laser light L is set to a low output of, for example, about several watts.

[0022] Subsequently, when the temperature measuring solder 20 is heated and melted by irradiation with the laser light L, the temperature of the melted temperature measuring solder 20 is measured by the temperature sensor 19c having the temperature measuring part 19c connected to the temperature measuring solder 20. -The temperature of the temperature-measuring solder 20 is directly measured by the radiation thermometer 7 19, and the measured value T1 (first measured value) is input to the controller 10. The temperature of the temperature-measuring solder 20 is also measured by the radiation thermometer 7 when infrared light emitted from the temperature-measuring solder 20 is received by the radiation thermometer 7 through the oxidation-resistant glass 23, and the measured value T2 (second measured value) is input to the controller 10. It is desirable that the first measured value T1 and the second measured value T2 are displayed on a display unit (not shown) provided in the controller 10 or in a position separate from the controller 10 so that the operator can confirm them.

[0023] Furthermore, even if the temperature-measuring solder 20 is heated and melted by the laser light L, the surface of the partition plate 18 and the surface of the antioxidant glass 23 are not wettable by the solder, so the solder does not spread along the surfaces of the partition plate 18 and the antioxidant glass 23, but remains in the position it was in before it melted.

[0024] Next, in the controller 10, the temperature sensor - The first measurement value T1 by the temperature sensor 19 is compared with the second measurement value T2 by the radiation thermometer 7, and if there is a difference between the two, an emissivity offset amount according to the difference (temperature difference) is calculated, and the emissivity of the radiation thermometer 7 is automatically offset according to the calculated emissivity offset amount. - The emissivity is rewritten to be equal to the first measured value T1 by the radiation thermometer 7, and the calibration of the radiation thermometer 7 is thereby completed. the temperature sensor - If there is no difference between the first measurement value T1 by 19 and the second measurement value T2 by the radiation thermometer 7, the emissivity of the radiation thermometer 7 is not rewritten and the calibration ends. When the calibration of the radiation thermometer 7 is completed, the irradiation head 6 and the radiation thermometer 7 are returned to the soldering position shown in FIGS. 1 and 2, and the soldering operation is started.

[0025] In this way, by calibrating the radiation thermometer 7 using the calibration thermometer 15, the calibration can be easily performed in a very short time (about 20 to 30 seconds) compared to when a blackbody furnace is used. Therefore, even during the soldering process, the radiation thermometer 7 can be calibrated without interrupting the soldering work, such as when replacing the printed circuit board 9 or when one batch process is completed and the next batch process is started. Moreover, the calibration thermometer 15 can be easily installed near the soldering area 8a where the printed circuit board 9 is placed during soldering, making installation easier than when a blackbody furnace is used.

[0026] Furthermore, the temperature sensor - By knowing that there is a difference between the first measurement value T1 by 19 and the second measurement value T2 by the radiation thermometer 7, it is possible to know if there is an abnormality in the radiation thermometer 7 or if there is dirt on the protective glass attached to the front of the radiation thermometer 7 to prevent fumes, flux, etc. from adhering, thereby improving maintainability. Furthermore, the output of the laser light L irradiated onto the calibration thermometer 15 can be as low as a few watts, which reduces power consumption and is economical. [Explanation of symbols]

[0027] 1 Soldering equipment 6 irradiation head 7 Radiation thermometer 15 Calibration thermometer 16 Body 17 Measurement room 18a hole 19 Temperature Sensor - 19a,19b Metal wire 19c Temperature measuring part 20 Temperature measuring solder 23 Anti-oxidation glass

Claims

1. A calibration thermometer for calibrating a radiation thermometer of a laser soldering device, comprising: A temperature measuring solder to be the object of temperature measurement and a temperature sensor to measure the temperature of the temperature measuring solder are housed inside a measurement chamber formed on the top surface of the body, the temperature sensor is made of a thermocouple in which two different metal wires are connected to each other, the connection point being a temperature measuring part for measuring temperature, and the temperature measuring solder is bonded to the temperature measuring part; An anti-oxidation glass is attached to the opening on the top surface of the measurement chamber to prevent oxidation of the temperature measuring solder, The laser light output from the laser soldering device is irradiated onto the temperature-measuring solder through the anti-oxidation glass, The temperature measuring solder is tightly adhered to the lower surface of the oxidation-resistant glass without any gaps. A calibration thermometer characterized by:

2. A partition plate on which the temperature-measuring solder is placed is provided in the measurement chamber, the lower surface of the oxidation-resistant glass and the upper surface of the partition plate are formed of a material that is not wettable by the temperature-sensing solder; 2. The calibration thermometer according to claim 1.

3. A hole is formed in the portion of the partition plate where the temperature measuring solder is placed, The temperature measuring portion of the temperature sensor is bonded to the bottom surface of the temperature measuring solder through the hole.

3. The calibration thermometer according to claim 2.

4. A method for manufacturing the calibration thermometer according to any one of claims 1 to 3, comprising: The temperature measuring solder is bonded to the oxidation-resistant glass by ultrasonic soldering. A method for manufacturing a calibration thermometer, comprising:

5. A method for calibrating the radiation thermometer using the calibration thermometer according to any one of claims 1 to 3, comprising: While the laser light is irradiated onto the temperature-measuring solder, the temperature of the temperature-measuring solder is measured by the temperature sensor, and the temperature of the temperature-measuring solder is also measured by the radiation thermometer, and the emissivity of the radiation thermometer is calibrated based on the measured values ​​of the temperature sensor and the radiation thermometer. A method for calibrating a radiation thermometer, comprising:

6. 4. A laser soldering apparatus, comprising: a calibration thermometer according to claim 1, disposed in the vicinity of a soldering area where a soldering portion is to be soldered.

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