Resistance heating and temperature measurement apparatus for friction stir additive manufacturing and methods of use thereof

Abstract

The application provides a resistance heating and temperature measuring device for friction stir additive manufacturing and a use method thereof, and the device comprises a spindle shell, a shaft sleeve, a heating resistance rod, a thermocouple, a conductive ring, a temperature controller and a rod; a hollow spindle is vertically arranged in the middle of the spindle shell, the shaft sleeve is connected with the lower end of the hollow spindle and is perpendicular to the outer side wall of the hollow spindle; a thermocouple connector is arranged on the shaft sleeve and is used for connecting the thermocouple; the conductive ring is arranged above the hollow spindle, the thermocouple connector is connected with the conductive ring and is connected with the temperature controller through the conductive ring; the heating resistance rod is arranged below the conductive ring and is connected with the conductive ring; the top of the rod is provided with a heating hole for heating, and the side of the rod is provided with a temperature measuring hole for temperature measurement. Through reasonable structure design and reasonable use of the conductive ring, the application solves the problems of heating and temperature measurement of the high-speed rotating rod, realizes the heating and temperature measurement of the rod for friction stir additive manufacturing, and is convenient to operate, accurate in measurement and safe and stable.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of additive forming and equipment manufacturing technology, in particular to a resistance heating and temperature measuring device for friction stir additive manufacturing and a use method thereof. BACKGROUND

[0002] Additive manufacturing does not require a mold, is not limited by structural complexity, has high material utilization, and can effectively complement traditional manufacturing methods. However, traditional additive manufacturing technologies such as laser additive manufacturing and electric arc additive manufacturing involve solid-liquid phase change during the additive process, which can cause a series of problems such as porosity, evaporation and spatter. Friction stir additive manufacturing is a new additive manufacturing technology that does not involve solid-liquid phase change during the additive process. After severe plastic deformation, the material has a dense structure without pores and is composed of fine equiaxed grains, which has good mechanical properties, fatigue properties and ductility. In addition, it has a series of advantages such as low energy consumption, fast processing rate and wide application range, and is a very promising additive manufacturing technology.

[0003] During the friction stir additive manufacturing process, an axial pressure is used to tightly press a consumable rod against the substrate. High-speed rotation and friction cause material deposition. After a short pause, the substrate is moved, causing the material to be deposited on the substrate or the previous additive layer in the opposite direction of the substrate travel direction. The above process is repeated multiple times to achieve the purpose of additive manufacturing. During the additive process, the rod and the material of the additive layer are the same, and have the same thermal physical parameters. Therefore, in order to control the deposition direction of the material during the additive process, the temperature difference between the two sides needs to be increased, that is, the temperature on one side of the rod needs to be high and the strength needs to be low, and the substrate side needs to be cooled quickly and the temperature needs to be low and the strength needs to be high, in order to achieve the purpose of directional additive manufacturing. In addition to cooling the substrate with cooling water, the temperature on one side of the rod can also be heated. However, the rod needs to be rotated at high speed and is wrapped by a shaft sleeve, so it is very difficult to heat and measure the temperature. SUMMARY

[0004] The purpose of the present application is to overcome the above-mentioned defects and develop a resistance heating and temperature measuring device for friction stir additive manufacturing and a use method thereof.

[0005] The purpose of the present application is achieved by the following technical solutions:

[0006] The present application provides a resistance heating and temperature measuring device for friction stir additive manufacturing, which comprises a main shaft housing, a shaft sleeve, a heating resistance rod, a thermocouple, a conductive ring, a temperature controller and a rod.

[0007] A hollow main shaft is vertically arranged in the middle of the main shaft housing, and the shaft sleeve is connected with the lower end of the hollow main shaft and is perpendicular to the outer side wall of the hollow main shaft. A thermocouple socket is arranged on the shaft sleeve, and the thermocouple socket is used to connect the thermocouple.

[0008] The conductive ring is arranged above the hollow spindle, the thermocouple socket is connected with the conductive ring, and the conductive ring is connected with the temperature controller through the conductive ring;

[0009] The heating resistance rod is arranged below the conductive ring and is connected with the conductive ring.

[0010] The top of the rod is provided with a heating hole, and the side of the rod is provided with a temperature measuring hole, the heating hole is used for placing the heating resistance rod, and the temperature measuring hole is used for placing the thermocouple.

[0011] As a preferred solution, the conductive ring comprises a conductive ring stator and a conductive ring rotor, the conductive ring stator is provided with a first conductive ring stator terminal post and a second conductive ring stator terminal post, and the conductive ring rotor is provided with a first conductive ring rotor terminal post and a second conductive ring rotor terminal post.

[0012] The first conductive ring rotor terminal post is connected with the thermocouple socket for placing the thermocouple at the bottom of the shaft sleeve through a second wire, the second conductive ring rotor terminal post is connected with the heating resistance rod through a third wire, and the first conductive ring stator terminal post and the second conductive ring stator terminal post are respectively connected with the temperature controller through a fourth wire and a fifth wire.

[0013] As a preferred solution, the second wire is arranged inside the hollow spindle, one end of the second wire is connected with the first conductive ring rotor terminal post, and the other end of the second wire is connected with one end of the thermocouple socket arranged inside the shaft sleeve after passing through a first through hole arranged on the side wall of the hollow spindle.

[0014] One end of the third wire is connected with the second conductive ring rotor terminal post, and the other end of the third wire is connected with the top end of the heating resistance rod after passing through the hollow cavity of the hollow spindle.

[0015] As a preferred solution, an insulating sleeve is further arranged inside the hollow cavity of the hollow spindle, and the second wire and the third wire are arranged in the insulating sleeve to prevent electric shock.

[0016] A second through hole is arranged on the insulating sleeve and communicates with the first through hole on the side wall of the hollow spindle, so that the second wire can pass through the insulating sleeve.

[0017] As a preferred solution, the heating resistance rod can be inserted into the heating hole of the rod to heat the rod.

[0018] The heating resistance rod comprises an upper clamping section and a lower heating section, the diameter of the upper clamping section is greater than that of the lower heating section, and when the heating resistance rod is inserted into the heating hole of the rod, the lower heating section of the heating resistance rod is entirely arranged in the heating hole of the rod, and the upper clamping section is partially arranged in the heating hole of the rod.

[0019] As a preferred solution, the rod can be sleeved in the hollow cavity of the hollow spindle, and a fixing hole is further arranged on the upper end side wall of the rod, and a groove is arranged on the side of the upper clamping section of the heating resistance rod, the groove is located on the side extending to the axial direction of the fixing hole and is in communication with the fixing hole; by installing a fixing device in the fixing hole and extending the fixing device into the groove, the heating resistance rod is fixed in the heating hole of the rod.

[0020] As a preferred solution, the resistance heating and temperature measuring device for the friction stir additive manufacturing is used in the following way: the upper end of the rod with the heating resistance rod fixed thereon is inserted into and fixed in the hollow spindle from the bottom of the hollow spindle, and the top end of the heating resistance rod is placed in the hollow cavity of the hollow spindle; and the lower end of the rod is located in the extension section outside the bottom of the hollow spindle, and the temperature measuring hole is located below the hollow spindle.

[0021] As a preferred solution, the thermocouple is connected with the thermocouple socket through the first wire, and the thermocouple can be inserted into the temperature measuring hole of the rod to detect the temperature of the rod.

[0022] The application further provides a friction stir additive manufacturing device comprising the resistance heating and temperature measuring device.

[0023] The application further provides a method for resistance heating and temperature measurement of a rod in a friction stir additive manufacturing process, comprising the following steps:

[0024] S1. The resistance heating rod is inserted into the heating hole of the rod, and the fixing device is inserted into the fixing hole of the rod to fix the heating resistance rod, then the upper end of the rod with the heating resistance rod fixed thereon is inserted into the hollow spindle and fixed.

[0025] S2. The thermocouple is inserted into the temperature measuring hole of the rod.

[0026] S3. The rod is vertically placed above the substrate, the temperature controller is turned on, and the thermocouple is started to monitor the temperature of the rod, and the heating resistance rod is started to preheat the rod to a preset temperature.

[0027] S4. The friction stir additive manufacturing device is started to rotate the hollow spindle, the shaft sleeve and the rod synchronously, and the spindle shell is not rotated at this time, so as to drive the rod to move horizontally and press downward, so that the material is deposited on the substrate to complete single-layer additive manufacturing.

[0028] S5. The position of the lower end surface of the rod is raised, and after the heating resistance rod and the thermocouple are reinstalled according to steps S1-S4, a new layer of additive manufacturing is started.

[0029] Compared with the prior art, the application has the following beneficial effects:

[0030] 1) The application inserts a heating resistance rod into a heating hole of the rod and tightens a fixing device, inserts a thermocouple into a temperature measuring hole on the side of the rod, and connects a first wire (i.e. a thermocouple wire) with a thermocouple socket on the shaft sleeve, so that the sample replacement operation is completed, and the complicated sample installation step is avoided.

[0031] 2) Through reasonable structural design and reasonable use of the conductive ring, the heating and temperature measurement of the high-speed rotating rod are solved.

[0032] 3) The application can also complete temperature measurement at different positions by changing the punching position and depth of the rod, which is convenient and fast.

[0033] 4) The method is convenient to detect, the test device has a reasonable structure, does not need to modify the instrument, and has strong universal applicability.

[0034] 5) The device of the application realizes heating and temperature measurement of the friction stir additive manufacturing rod, is convenient to operate, accurate in measurement, and safe and stable. BRIEF DESCRIPTION OF DRAWINGS

[0035] Other features, objects and advantages of the application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings:

[0036] Figure 1 is a sectional view of the resistance heating and temperature measurement device for the friction stir additive manufacturing of the application;

[0037] Figure 2 is a front view of the resistance heating and temperature measurement device for the friction stir additive manufacturing of the application;

[0038] Figure 3 is a top view of the resistance heating and temperature measurement device for the friction stir additive manufacturing of the application;

[0039] Figure 4 is a sectional view of the rod in the resistance heating and temperature measurement device for the friction stir additive manufacturing of the application;

[0040] Figure 5 is a position diagram of the resistance heating and temperature measurement device for the friction stir additive manufacturing of the application in the friction stir additive manufacturing device;

[0041] Figure 6 is a schematic diagram of the measurement results of Example 1;

[0042] Corresponding name of reference sign: 1-substrate, 2-rod, 3-thermocouple, 4-first wiring, 5-thermocouple socket, 6-main shaft shell, 7-resistance heating rod, 8-second wiring, 9-third wiring, 10-conductive ring, 11-first conductive ring stator terminal post, 12-first conductive ring rotor terminal post, 13-second conductive ring rotor terminal post, 14-second conductive ring stator terminal post, 15-hollow main shaft, 16-insulating sleeve, 17-fourth wiring, 18-fifth wiring, 19-shaft sleeve, 20-temperature controller, 21-temperature measuring hole, 22-heating hole, 23-fixing hole, 24-workbench, 25-welder body. DETAILED DESCRIPTION

[0043] The application will be described in detail below with specific examples. The following examples will help those skilled in the art to further understand the application, but do not limit the application in any form. It should be pointed out that for those skilled in the art, without departing from the concept of the application, a number of modifications and improvements can be made. These all belong to the protection scope of the application.

[0044] Example 1

[0045] The embodiment relates to a resistance heating and temperature measuring device for friction stir additive manufacturing (the embodiment selects magnesium alloy friction stir additive manufacturing), as shown in the figure, the device comprises a main shaft shell 6, a shaft sleeve 19, a heating resistance rod 7, a thermocouple 3, a conductive ring, a temperature controller 20 and a rod 2. Figures 1-4

[0046] The middle part of the main shaft shell 6 is vertically provided with a hollow main shaft 15; the shaft sleeve 19 is fixedly connected with the lower end part of the hollow main shaft 15 and is perpendicular to the outer side wall of the hollow main shaft 15; the hollow main shaft 15 is internally provided with an insulating sleeve 16, the upper part of the hollow main shaft is provided with a conductive ring, and the conductive ring is connected with the main shaft shell and the insulating sleeve 16 in the hollow main shaft, respectively. The main shaft shell 6 is not connected with the hollow main shaft 15 and the shaft sleeve, and is located outside the hollow main shaft 15 and the shaft sleeve 19. The shaft sleeve 19 is provided with a thermocouple socket 5, and the thermocouple socket 5 is used for connecting the thermocouple 3.

[0047] ​The conductive ring comprises a conductive ring stator and a conductive ring rotor, and the specific internal structure is the existing conductive ring structure, which is not described herein. The conductive ring stator is connected with the main shaft shell 6, and the conductive ring rotor is connected with the insulating sleeve 16. The conductive ring stator is provided with a first conductive ring stator terminal post 11 and a second conductive ring stator terminal post 14, and the conductive ring rotor is provided with a first conductive ring rotor terminal post 12 and a second conductive ring rotor terminal post 13; the first conductive ring stator terminal post 11, the first conductive ring rotor terminal post 12, the second conductive ring rotor terminal post 13 and the second conductive ring stator terminal post 14 are sequentially arranged along the diameter direction of the conductive ring; wherein the first conductive ring stator terminal post 11 is connected with the temperature controller 20 through the fourth wire 17, and the second conductive ring stator terminal post 14 is connected with the temperature controller 20 through the fifth wire 18. In order to make the second wire 8 pass through the hollow main shaft 15, a through hole is arranged on the side wall of the hollow main shaft 15, so that one end of the second wire 8 is connected with the first conductive ring rotor terminal post 12, and the other end passes through the second through hole on the side wall of the insulating sleeve 16, and then passes through the first through hole on the side wall of the hollow main shaft 15 which is communicated with the second through hole, and then is connected with one end of the thermocouple socket 5 arranged inside the shaft sleeve 19; and the other end of the thermocouple socket 5 arranged outside the shaft sleeve 19 is connected with the thermocouple 3 through the first wire 4, so that the temperature controller 20 is in contact with the thermocouple 3 through the conductive ring. The second conductive ring rotor terminal post 12 is connected with the heating resistance rod 7 through the third wire 9, so that the temperature controller 20 is in contact with the heating resistance rod 7 through the conductive ring. The second wire 8 and the third wire 9 can pass through the insulating sleeve 16, which can avoid electric shock and improve the safety of the equipment.

[0048] The heating resistance rod 7 comprises an upper clamping section and a lower heating section, the top of the upper clamping section is connected with the second conductive ring rotor terminal post 13 through the third connecting wire 9; the diameter of the upper clamping section is larger than that of the lower heating section. The top of the rod 2 is provided with a heating hole 22 for placing the heating resistance rod 7. The upper end side wall of the rod 2 is further provided with a fixing hole 23, the side surface of the upper clamping section of the heating resistance rod 7 is provided with a groove, the groove is located on the side extending to the axial direction of the fixing hole 23 and is in communication with the fixing hole 23; the heating resistance rod 7 can be fixed in the heating hole 23 of the rod 2 by installing a fixing device (such as a fastening screw) in the fixing hole 23 and extending the fixing device into the groove. When the rod 2 is heated, the resistance heating rod 7 is inserted into the heating hole 22 of the rod 2, the lower heating section of the heating resistance rod 7 is completely sleeved in the heating hole 22 of the rod 2, the upper clamping section is partially sleeved in the heating hole 22 of the rod 7, the fixing hole 23 of the rod 2 is aligned with the groove on the heating resistance rod 7, and then the fixing device is inserted for fixation to prevent the heating resistance rod 7 from sliding out during the friction stir additive manufacturing process, and then the heating resistance rod 7 can be turned on to heat the rod 2. During heating, only the lower heating section of the heating resistance rod 7 heats the rod 2, and the upper clamping section is not heated to prevent the upper clamping section from being overheated and failing, and to improve energy utilization. In a specific embodiment, after the heating resistance rod 7 is inserted into the heating hole 22, an appropriate amount of heat-conducting silicone can be injected to improve the heating rate. When the heating resistance rod 7 is used, it is located below the conductive ring, the third connecting wire 9 connected with the second conductive ring rotor terminal post 13 is extended along the axial direction of the hollow spindle 15 and connected with the heating resistance rod 7, then the heating resistance rod 7 is connected with the rod 2, and then they are inserted into the hollow spindle 15 together.

[0049] The thermocouple 3 is detachably installed on the thermocouple socket 5 through a screw, since the thermocouple socket 5 is fixedly connected with the conductive ring rotor through the second connecting wire 8, and the thermocouple 3 is connected with the thermocouple socket 5 through the first connecting wire 4, the thermocouple 3 only needs to be twisted to be detached, without the need to repeatedly pass the thermocouple wire through the hollow spindle 15 and connect it with the conductive ring, which is more convenient to operate.

[0050] The lower end side of the rod 2 is also provided with a temperature measuring hole 21 for sleeving a thermocouple 3 to monitor the temperature of the rod 2. When monitoring the temperature of the rod 2, the thermocouple 3 is inserted into the temperature measuring hole 21 of the rod 2 after being detached from the thermocouple socket 5, and then the temperature monitoring of the rod 2 can be realized by turning on the thermocouple 3. In a specific embodiment, after the thermocouple 3 is inserted into the temperature measuring hole 21, a proper amount of heat-conducting silica gel can be injected to improve the temperature measuring sensitivity and prevent the thermocouple 3 from flying out during the high-speed rotation process of the friction stir additive manufacturing. In a specific embodiment, the temperature measuring hole 21 is a slanted hole with a certain upward inclination angle. The depth and position of the temperature measuring hole can be designed according to different needs to facilitate the obtaining of temperature changes at different positions.

[0051] The resistance heating and temperature measuring device for friction stir additive manufacturing is used by inserting and fixing the upper end of the rod 2 with the fixed heating resistance rod 7 into the hollow spindle 15 from the bottom of the hollow spindle 15, so that the top end of the upper clamping section of the heating resistance rod 7 which is not inserted into the heating hole 22 is located in the hollow cavity of the hollow spindle 15, and the lower end of the rod 2 is located in the extension section outside the bottom of the hollow spindle 15, so that the temperature measuring hole 21 is located below the hollow spindle 15.

[0052] The embodiment also provides a friction stir additive manufacturing device based on the foregoing resistance heating and temperature measuring device, as shown in the accompanying drawings, which comprises the foregoing resistance heating and temperature measuring device, a welding machine body 25 connected with the spindle shell 6, and a workbench 24 for processing the substrate 1. The specific structure of the welding machine body 25 is the same as that of the corresponding structure of the existing friction stir additive manufacturing device, which will not be described here. Figure 5

[0053] The method for testing the resistance heating and temperature measuring device for friction stir additive manufacturing of the embodiment comprises the following steps:

[0054] 1) Place the insulating sleeve 16 inside the hollow spindle 15, fix the conductive ring rotor on the insulating sleeve 16, connect the conductive ring stator with the spindle shell 6, connect one end of the second wire 8 and the third wire 9 to the corresponding wire column of the conductive ring rotor, and connect one end of the fourth wire 17 and the fifth wire 18 to the corresponding wire column of the conductive ring stator.

[0055] 2) The other end of the second wire 8 passes through the first through hole provided on the insulating sleeve 16 and the second through hole provided on the sidewall of the hollow spindle 15, and then connects the one end of the thermocouple socket 5 provided on the inside of the shaft sleeve; the other end of the third wire passes through the insulating sleeve 16 inside the hollow spindle 15 and connects the heating resistance rod 7; the other ends of the fourth wire 17 and the fifth wire 18 are connected with the temperature controller 20, so that the heating resistance rod 7 is connected with the temperature controller 20;

[0056] ​3) Insert the resistance heating rod 7 into the heating hole 22 of the rod 2, then inject the heat-conducting silica gel, and insert the fixing device into the fixing hole 23 of the rod 2 to fix the heating resistance rod 7, then insert the upper end of the rod 2 with the fixed heating resistance rod 7 into the hollow main shaft 15 and fix it;

[0057] 4) Insert the thermocouple 3 into the temperature measuring hole 21 of the rod 2, inject the heat-conducting silica gel, and connect the thermocouple 3 with the thermocouple socket 5 on the outer side of the shaft sleeve by the first wire 4, so that the thermocouple 3 is connected with the temperature controller 20 through the thermocouple socket 5 and the conductive ring;

[0058] 5) Place the rod 2 vertically above the base plate 1, turn on the temperature controller 20, start the heating resistance rod 7 to preheat the rod 2, heat the rod 2 to a pre-set temperature of 250℃, and start the thermocouple 3 to monitor the temperature of the rod 2; start the friction stir additive manufacturing when the temperature reaches 200℃, so that the hollow main shaft 15, the shaft sleeve 19 and the rod 2 rotate synchronously, thereby driving the rod 2 to move transversely and press down, so that the material is deposited on the base plate 1 to complete a single layer of additive manufacturing. In this embodiment, the processing parameters of the additive process are as follows: rotation speed 800 rpm, travel speed 40 mm / min, and pressing speed 10 mm / min, and the travel starts after 2 min of pressing.

[0059] The test results of the rod temperature when the additive manufacturing is performed by the above method are shown in Table 1. Figure 2 As shown in Table 1, the rod temperature is heated to 200℃ by the resistance heating and temperature measuring device of this embodiment after 6 min of heating, while the base plate temperature is only about 25℃, so that the temperature on one side of the rod is much higher than that on the other side, thereby achieving the purpose of increasing the temperature difference between the two sides.

[0060] 6) When the next layer of additive is performed, the heating resistance rod 7 and the thermocouple 3 are re-installed by the steps 1)-5) described above, and then the corresponding additive processing program is performed, wherein the heating temperature and the processing parameters can be adjusted according to the actual additive requirements.

[0061] The above description of the embodiments is for the purpose of facilitating the understanding and use of the invention by those skilled in the art. Those skilled in the art can easily make various modifications to these embodiments, and apply the general principles described herein to other embodiments without creative labor. Therefore, the present application is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present application should be within the scope of protection of the present application.

Claims

1. A resistance heating and temperature measuring device manufactured by friction stir additive manufacturing, characterized in that, The device consists of a spindle housing, a bushing, a heating resistance rod, a thermocouple, a conductive ring, a temperature controller, and a rod. A hollow spindle is vertically arranged in the middle of the spindle housing. A bushing is connected to the lower end of the hollow spindle and is perpendicular to the outer wall of the hollow spindle. A thermocouple socket is provided on the bushing for connecting thermocouples. The conductive ring is positioned above the hollow main shaft, and the thermocouple socket is connected to the conductive ring and connected to the temperature controller through the conductive ring. The heating resistance rod is positioned below the conductive ring and connected to the conductive ring; The top of the rod is provided with a heating hole, and the side of the rod is provided with a temperature measuring hole. The heating hole is used to place the heating resistance rod, and the temperature measuring hole is used to place the thermocouple. The conductive ring includes a conductive ring stator and a conductive ring rotor. The conductive ring stator is provided with a first conductive ring stator terminal and a second conductive ring stator terminal, and the conductive ring rotor is provided with a first conductive ring rotor terminal and a second conductive ring rotor terminal. The first conductive ring rotor terminal is connected to the thermocouple socket at the bottom of the bushing via the second terminal, and the second conductive ring rotor terminal is connected to the heating resistance rod via the third terminal. The first conductive ring stator terminal and the second conductive ring stator terminal are connected to the temperature controller via the fourth and fifth terminals, respectively. The second wiring is set inside the hollow spindle. One end of the second wiring is connected to the rotor terminal of the first conductive ring, and the other end passes through the first through hole set on the side wall of the hollow spindle and is connected to one end of the thermocouple socket set inside the bushing. One end of the third wiring is connected to the rotor terminal of the second conductive ring, and the other end passes through the hollow cavity of the hollow main shaft and is connected to the top of the heating resistance rod. The heating resistance rod can be inserted into the heating hole of the rod to heat the rod. The heating resistance rod includes an upper clamping section and a lower heating section; the diameter of the upper clamping section is larger than that of the lower heating section; when the heating resistance rod is inserted into the heating hole of the rod, the lower heating section of the heating resistance rod is completely fitted into the heating hole of the rod, and the upper clamping section is partially fitted into the heating hole of the rod. The thermocouple is connected to the thermocouple socket via the first wiring, and the thermocouple can be inserted into the temperature measuring hole of the rod to realize the temperature detection of the rod.

2. The resistance heating and temperature measuring device for friction stir additive manufacturing according to claim 1, characterized in that, An insulating sleeve is also provided inside the hollow cavity of the hollow spindle, and the second and third wires are located inside the insulating sleeve to prevent electric shock. The insulating sleeve is provided with a second through hole that is connected to the first through hole on the side wall of the hollow spindle, so that the second wiring can pass through the insulating sleeve.

3. The resistance heating and temperature measuring device for friction stir additive manufacturing according to claim 1, characterized in that, The rod can be sleeved in the hollow cavity of the hollow main shaft. A fixing hole is also provided on the upper end side wall of the rod. A groove is provided on the side of the upper clamping section of the heating resistance rod. The groove is located on the side of the fixing hole extending towards the axis and can communicate with the fixing hole. By installing a fixing device in the fixing hole and extending the fixing device into the groove, the heating resistance rod is fixed in the heating hole of the rod.

4. The resistance heating and temperature measuring device for friction stir additive manufacturing according to claim 1, characterized in that, When using the resistance heating and temperature measuring device manufactured by friction stir additive manufacturing, the upper end of the rod with the heating resistance rod fixed is inserted into and fixed inside the hollow main shaft from the bottom, so that the top end of the heating resistance rod is placed inside the hollow cavity of the hollow main shaft; while the lower end of the rod is located as an extension outside the bottom of the hollow main shaft, so that the temperature measuring hole is located below the hollow main shaft.

5. A stir friction additive manufacturing apparatus comprising the resistance heating and temperature measuring device according to any one of claims 1-4.

6. A method for resistance heating and temperature measurement of a bar during friction stir additive manufacturing, characterized in that, Includes the following steps: S1. Using the friction stir additive manufacturing apparatus of claim 5, a resistance heating rod is inserted into the heating hole of the rod, and a fixing device is inserted into the fixing hole of the rod to fix the heating resistance rod. Then, the upper end of the rod with the heating resistance rod fixed is inserted into the hollow main shaft and fixed. S2. Insert the thermocouple into the temperature measuring hole of the rod; S3. Place the rod vertically above the substrate, turn on the temperature controller and start the thermocouple to monitor the temperature of the rod, and start the heating resistance rod to preheat the rod to the preset temperature. S4. Start the friction stir additive manufacturing device to make the hollow spindle, bushing and rod rotate synchronously. At this time, the spindle housing does not rotate, thereby driving the rod to move laterally and press down, so that the material is deposited on the substrate to complete the single-layer additive manufacturing. S5. Raise the position of the lower end face of the rod, and after reinstalling the heating resistance rod and thermocouple according to steps S1-S4, start a new layer of additive manufacturing.

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