Friction stir bonding device

Abstract

To provide a friction stir bonding device that is related to friction stir bonding, measures the temperature of a bonding object material and performs control of a rotational tool and electric heating of the bonding object material on the basis of the temperature of the bonding object material.SOLUTION: There is provided a friction stir bonding device for bonding a bonding object material with a rotational tool by friction in which the temperature of the bonding object material is evaluated from a potential difference between the rotational tool and the bonding object material, at least one of the feed rate and rotational speed of the rotational tool is controlled on the basis of the temperature of the bonding object material, electric heating of the bonding object material is controlled on the basis of the temperature of the bonding object material, a voltmeter for the potential difference measurement and a power supply for the electric heating are connected in parallel in an electrical circuit including the rotational tool and the bonding object material, and the potential difference measurement and the electric heating are performed by switching between the voltmeter and the power supply.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a friction stir welding apparatus. [Background technology]

[0002] Friction stir welding is known as one of the joining techniques, in which the deformation resistance of the materials to be joined is reduced by frictional heat, and then the materials are stirred (plastic flow) to join them. In friction stir welding, temperature control during welding is important, and the following method has been disclosed as a method of performing friction stir welding and cutting while measuring the temperature.

[0003] For example, Patent Document 1 discloses a temperature / load measurement method for friction stir welding that measures the temperature and load of workpieces during friction stir welding in real time, and further discloses that the method may include outputting the change in electrical resistance of an electrical resistance strain gauge attached at a position away from a rotating tool held by a tool holder connected to a spindle of a friction stir welding device as a load signal, outputting the electromotive force of a thermocouple in a rotating tool held by the tool holder as a temperature signal, and outputting the load signal of the electrical resistance change and the temperature signal of the electromotive force in real time on the same time axis. According to the temperature / load measurement method for friction stir welding described in Patent Document 1, it is possible to measure the temperature and load in order to appropriately control the plastic flow of the workpieces, and it is possible to detect abnormalities / defects on the workpieces and abnormalities on the tool side in real time with high accuracy and high sensitivity from the change in temperature and load over time simply by replacing a general-purpose friction stir welding device with this tool holder-type friction stir measurement device, and it is also possible to easily search for welding conditions that can improve welding efficiency.

[0004] Patent Document 2 discloses a method for measuring the temperature distribution on a tool flank, which comprises drilling a small hole in the surface of a workpiece, embedding a thin metal wire that forms a thermocouple in the small hole in a state insulated from the tool by contacting the tool tip, and using the thermocouple to sequentially detect the temperature at the contact position between the thin metal wire and the tool tip while cutting the workpiece with the tool, thereby measuring the temperature distribution on the tool flank that is in contact with the workpiece. This method for measuring the temperature distribution on a tool flank is said to enable accurate measurement of the temperature distribution on the tool flank by a very simple means, without the need for processing such as drilling a large number of holes on the tool side for measuring the temperature distribution. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2022-162847 A [Patent Document 2] Japanese Patent Application Publication No. 62-88551 Summary of the Invention [Problem to be solved by the invention]

[0006] In order to perform friction stir welding properly, it is desirable to accurately measure the temperature of the parts to be joined and keep it at a desired temperature. Therefore, an object of the present disclosure is to provide a friction stir welding device that can keep the parts to be joined at a desired temperature and can perform proper joining. [Means for solving the problem]

[0007] The present disclosure achieves the above object by the following means.

[0008] <1> A friction stir welding apparatus that frictionally welds workpieces with a rotating tool, evaluating a temperature of the workpieces based on a potential difference between the rotating tool and the workpieces; controlling at least one of a feed speed and a rotation speed of the rotary tool based on a temperature of the workpiece; Controlling electrical heating of the workpieces based on the temperature of the workpieces; In an electric circuit including the rotating tool and the workpiece, a voltmeter for measuring the potential difference and a power source for the electric heating are connected in parallel, and the voltmeter and the power source are switched to measure the potential difference and perform the electric heating. Friction stir welding equipment. Effect of the Invention

[0009] According to the friction stir welding apparatus of the present disclosure, the joint parts can be kept at a desired temperature, and friction stir welding can be performed appropriately. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram for explaining how the temperature is evaluated from the potential difference between the rotating tool of the friction stir welding apparatus of the present disclosure and the workpieces. [Diagram 2] FIG. 2 is a schematic diagram for explaining a friction stir welding apparatus according to the present disclosure which performs resistance heating and potential difference measurement by switching between an electric circuit for resistance heating and an electric circuit for potential difference measurement. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present disclosure will be described in detail. Note that the present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present disclosure.

[0012] 《Friction stir welding equipment》 The friction stir welding apparatus of the present disclosure is A friction stir welding apparatus that frictionally welds workpieces with a rotary tool, evaluating a temperature of the workpieces based on a potential difference between the rotating tool and the workpieces; controlling at least one of a feed speed and a rotation speed of the rotary tool based on a temperature of the workpiece; Controlling electrical heating of the workpieces based on the temperature of the workpieces; In an electric circuit including the rotating tool and the workpiece, a voltmeter for measuring the potential difference and a power source for the resistive heating are connected in parallel, whereby the voltmeter and the power source are switched to measure the potential difference and perform the resistive heating.

[0013] According to the friction stir welding apparatus of the present disclosure, the joint parts can be kept at a desired temperature, and friction stir welding can be performed appropriately.

[0014] When the rotating tool and the workpieces are electrically connected, a voltage difference occurs due to thermoelectromotive force caused by the Seebeck effect depending on the temperature of the workpieces. By acquiring the relationship between the potential difference and temperature in advance, it is possible to measure the temperature from the potential difference between the rotating tool and the workpieces. In other words, by configuring a thermocouple between the rotating tool and the workpieces, it is possible to measure the temperature of the interface of the workpieces by utilizing the potential difference caused by the thermoelectromotive force generated between the rotating tool and the workpieces.

[0015] In the friction stir welding apparatus of the present disclosure, the rotating tool is controlled based on the temperature. Specifically, when the temperature is lower than a temperature appropriate for friction stir welding, the feed speed of the rotating tool is decreased or the rotation speed of the rotating tool is increased, and when the temperature is higher than a temperature appropriate for friction stir welding, the feed speed of the rotating tool is increased or the rotation speed of the rotating tool is decreased.

[0016] Furthermore, when the temperature suitable for friction stir welding cannot be reached by friction heat alone based on the above temperature, the rotating tool and the workpieces can be heated by passing electricity through them. Based on the temperature of the workpieces, the rotating tool can be controlled and electrically heated, so that the joining part can be kept at a desired temperature, and friction stir welding can be performed appropriately.

[0017] <Evaluation of the temperature of the joined materials> The friction stir welding apparatus of the present disclosure is The temperature of the workpieces is evaluated from the potential difference between the rotating tool and the workpieces.

[0018] FIG. 1 is a schematic diagram showing one embodiment in which the temperature is evaluated from the potential difference between a rotating tool and workpieces in the friction stir welding apparatus of the present disclosure, but the present invention is not limited to this embodiment.

[0019] The rotating tool 11 is provided on a rotating mechanism 12, and is equipped with a slip ring 13 and a brush 14. The rotating tool 11 is pressed against materials to be joined, for example, a two-layered laminate of materials to be joined, 15 and 16. The materials to be joined are placed on a table 18, and an insulator 17 is placed between the materials to be joined and the table 18.

[0020] The rotating tool 11 is not particularly limited, but the probe diameter and the probe length can be designed arbitrarily according to the depth of the materials to be joined, etc. The slip ring 13 and the brush 14 are not particularly limited, but they may be anything that can transmit power and signals to the rotating body.

[0021] The rotating tool 11 is electrically connected to the workpiece 15 with which the rotating tool 11 is in contact via a slip ring 13 and a brush 14. The potential difference between the rotating tool 11 and the workpiece 15 is measured by a voltmeter 20 as the potential difference across a resistor 19. In this manner, a thermocouple may be provided between the rotating tool 11 and the workpiece 15, and the temperature of the workpiece may be measured using the potential difference caused by the thermoelectromotive force generated between the rotating tool 11 and the workpiece 15. In order to accurately measure the potential difference caused by the thermoelectromotive force, it is preferable to provide an insulator, for example a ceramic insulator, between the workpiece and the table 18, although this is not particularly limited.

[0022] In order to obtain the temperature from the potential difference due to the thermoelectromotive force, the relationship between the potential difference and the temperature may be obtained in advance using an electric furnace. Specifically, for example, the metal of the material of the workpiece and the metal of the rotating tool are placed in contact with each other in an electric furnace, the temperature is changed, and the relationship between the potential difference and the temperature is obtained. This makes it possible to obtain the temperature of the workpiece from the thermoelectromotive force generated by the frictional heat between the rotating tool and the workpiece.

[0023] The material to be joined is not particularly limited, but may be any material that can form a thermocouple with the rotating tool, and examples of such materials include aluminum alloys, magnesium alloys, titanium alloys, steel materials, etc. The material to be joined is not particularly limited, but may be a single layer or a laminate of two or more layers, or may be two materials to be joined butted together.

[0024] Temperature-Based Rotary Tool Control The friction stir welding apparatus of the present disclosure is At least one of the feed speed and the rotation speed of the rotary tool is controlled based on the temperature of the workpieces.

[0025] The feed speed and rotation speed of the rotating tool are not particularly limited, and may be controlled by, for example, a rotation mechanism or a control device. When the temperature of the workpieces is lower than the temperature appropriate for joining, the rotating tool may be controlled to reduce the feed speed of the rotating tool or increase the rotation speed of the rotating tool in order to generate heat due to friction between the rotating tool and the workpieces. On the other hand, when the temperature of the workpieces is higher than the temperature appropriate for joining, the rotating tool may be controlled to increase the feed speed of the rotating tool or decrease the rotation speed of the rotating tool in order to suppress heat generation due to friction between the rotating tool and the workpieces.

[0026] <Temperature-based electrical heating> The friction stir welding apparatus of the present disclosure is Controlling electrical heating of the workpieces based on the temperature of the workpieces; In an electrical circuit including the rotating tool and the workpiece, a voltmeter for measuring the potential difference and a power source for the resistive heating are connected in parallel, whereby the potential difference measurement and the resistive heating are performed by switching between the voltmeter and the power source.

[0027] FIG. 2 is a schematic diagram showing one embodiment of the friction stir welding apparatus disclosed herein that switches between an electric circuit for resistive heating and an electric circuit for potential difference measurement to perform resistive heating and potential difference measurement, but is not limited to this case.

[0028] The rotating tool 11 is provided on a rotating mechanism 12, and is equipped with a slip ring 13 and a brush 14. The rotating tool 11 is pressed against materials to be joined, for example, a two-layered laminate of materials to be joined, 15 and 16. The materials to be joined are placed on a table 18, and an insulator 17 is placed between the materials to be joined and the table 18.

[0029] As an electric circuit for resistive heating, a power supply for resistive heating 21 is connected to the workpieces 15 and a switching circuit 22. Similarly, as an electric circuit for measuring a potential difference, a resistor 19 and a voltmeter 20 are connected to the workpieces 15 and the switching circuit 22. The switching circuit 22 is connected to the rotating tool 11 via the slip ring 14 and the brush 13. The switching circuit 22 can switch between the electric circuit for resistive heating and the electric circuit for measuring a potential difference, and thereby the friction stir welding apparatus of the present disclosure can heat the joint and measure the temperature based on the potential difference.

[0030] When the temperature rise is insufficient only by the frictional heat between the rotating tool and the workpieces, the workpieces may be heated to an appropriate temperature by applying electrical current to them.

[0031] 《Friction stir welding method》 The friction stir welding method disclosed herein is a friction stir welding method in which workpieces are joined by friction with a rotary tool, Evaluating a temperature of the workpieces from a potential difference between the rotating tool and the workpieces; controlling at least one of a feed speed and a rotation speed of the rotary tool based on a temperature of the workpiece; heating the workpieces through electrical current based on the temperature of the workpieces; a voltmeter for measuring the potential difference and a power source for the electric heating are connected in parallel in an electric circuit including the rotating tool and the workpiece, and the potential difference measurement and the electric heating are performed by switching between the voltmeter and the power source; Includes. [Explanation of symbols]

[0032] 11 Rotary tools 12 Rotation mechanism 13 Slip ring 14 Brush 15 Material to be joined 16 Material to be joined 17 Insulators 18 Tables 19 Resistance 20 Voltmeter 21 Electric heating power supply 22 Switch Circuit

Claims

[Claim 1] A friction stir welding apparatus that frictionally welds workpieces with a rotary tool, evaluating a temperature of the workpieces from a potential difference between the rotating tool and the workpieces; controlling at least one of a feed speed and a rotation speed of the rotary tool based on the temperature of the workpiece; Controlling electrical heating of the workpieces based on the temperature of the workpieces; a voltmeter for measuring the potential difference and a power source for the electric heating are connected in parallel in an electric circuit including the rotating tool and the workpiece, and the potential difference measurement and the electric heating are performed by switching between the voltmeter and the power source. Friction stir welding equipment.

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