A method and apparatus for roll-to-roll fabrication of REBCO multi-core tapes based on diamond knives

Abstract

The application discloses a kind of based on diamond cutter roll-to-roll preparation REBCO multi-core tape method and device.The device includes: base, support seat, bolt, coil chuck, servo motor, placement plate, positioning block, support sheet metal, guide wheel, guide column, workbench, placement plate, guide wheel, diamond cutter, fixed cutter block, screw rod, support table, grating ruler, rotating handle.Superconducting tape is rolled by the servo motor control coil chuck on two ends placement plate and is wound and reeled, and guide wheel is used to tape guide, four guide wheels on workbench are used to guide and fixed tape to facilitate cutting, by fixed cutter block fixed diamond cutter, then, after using micrometer grating ruler, screw rod and rotating handle determine processing depth, process at workbench.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of mechanical cutting of REBCO superconducting tapes, i.e. dividing the superconducting layer of REBCO superconducting tapes into multi-core tapes, and in particular to a method and device for preparing REBCO multi-core tapes based on diamond knife roll-to-roll. BACKGROUND

[0002] REBCO high temperature superconducting tapes, as one of the fastest growing high temperature superconducting materials in recent years, have the advantages of high mechanical strength, strong current carrying capacity, high upper critical magnetic field, and low production cost. However, on the one hand, due to the high aspect ratio of REBCO high temperature superconducting tapes, it leads to very high magnetic hysteresis loss. On the other hand, in alternating current applications, a field component perpendicular to the REBCO tape usually appears, which leads to the induction of circulating shielding current in the REBCO superconducting layer. The superposition of shielding current and transport current leads to electrical loss, which greatly limits the application of REBCO high temperature superconducting tapes. Especially when REBCO high temperature superconducting tapes are applied to magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR), some challenges are faced, such as the generation of large shielding current when wound into coils, the degradation of critical current after epoxy impregnation of REBCO coils, and heat loss caused by overcurrent. For the last two problems, some effective solutions have been proposed. As for the problem of generating large shielding current when wound into coils, although there are many methods currently used, such as mechanical grinding, chemical etching, laser cutting, etc. to divide the REBCO superconducting layer in the high temperature superconducting tape into several filaments, thereby reducing the shielding current. However, the above methods are still in the experimental stage, and the critical performance of the multi-core tapes processed by the above methods has a large decrease compared with the unprocessed critical performance. At present, a new preparation method called mechanical pressing method has been proposed. The multi-core tapes prepared by this method not only have a decrease in critical performance within an acceptable range, but also greatly reduce the alternating current loss. However, this method has not yet designed a relatively precise preparation device. Therefore, for this new method of mechanical pressing, a new mechanical processing device is urgently needed to prepare REBCO multi-core tapes.

[0003] Patent application publication no. CNB102484198 discloses a multi-filament conductor and a method for manufacturing the same, wherein the multi-filament conductor is designed with a tape substrate and at least one superconducting layer, wherein the superconducting layer is divided into several filaments, the tape substrate has a first direction extending parallel to its longitudinal direction, and at least one filament has a second direction extending parallel to its longitudinal direction, the first direction and the second direction form a non-zero angle. The multi-filament conductor can be designed such that the filaments are formed on the front and back surfaces of the conductor and are electrically connected to each other in such a way as to produce a staggered conductor. Compared with the present application, the manufacturing method is to divide the superconducting layer in the tape forming process. Since the REBCO tape is prepared based on the physical vapor deposition method, a stabilizing layer needs to be coated on the multi-filament superconducting layer after the superconducting layer is prepared, which affects the effect of the multi-filament superconducting layer.

[0004] International patent application publication no. WO2016024528 discloses a method and a device for manufacturing a high-temperature superconducting multi-core tape. The device mainly comprises a guide roller, a hard alloy cutter, a rotating member opposite to the guide roller, and a take-up portion and a feed portion for conveying the high-temperature superconducting tape between the guide roller and the rotating member. Compared with the present application, the device does not design a control system for the diamond, and cannot well control the depth and width of the cutter cutting, resulting in uneven performance of the prepared multi-core tape. In addition, the hard alloy is selected as the preparation material of the cutter, and the cutter is easily broken after a long time of cutting the tape, which not only consumes the cutter, but also needs to replace the cutter in time.

[0005] The preparation of REBCO multi-core tape is an effective method to reduce the shielding current of the wound coil, and the performance of the prepared REBCO multi-core tape will determine its performance. At present, the methods for preparing REBCO multi-core tape include mechanical grinding, chemical etching, and laser cutting. However, the minimum width of the superconducting core groove obtained by mechanical grinding and chemical etching is about 0.2 mm, which destroys the stabilizing layer and causes the critical current to decrease by about half, and also causes the mechanical strength of the tape to decrease. The laser cutting method causes the material of the stabilizing layer to remain in the groove between the core filaments, which cannot reduce the alternating current loss due to coupling. In addition, the existing mechanical cutting device does not design a control system for the diamond and a cutter that can cut for a long time. SUMMARY

[0006] The purpose of the present application is to provide a method and a device for preparing REBCO multi-core tape based on diamond cutter roll-to-roll. The mechanical device and the preparation method can not only realize the rapid preparation of superconducting multi-core tape, but also prepare multi-core tape with uniform cutting depth and width by designing a control system for the diamond and a diamond cutter. Since the cutter does not need to be replaced frequently, the efficiency of preparation is greatly improved, and the prepared multi-core tape has more excellent performance.

[0007] The technical scheme of the present application is: a device for roll-to-roll preparation of REBCO multi-core tape based on diamond cutter, which comprises a base, a support seat, a bolt, a coil chuck, a placement plate, a servo motor, a positioning block, a support sheet metal, a guide wheel, a guide column, a workbench, a placement plate, a guide wheel, a diamond cutter, a fixed cutter block, a lead screw, a support table, a grating ruler, and a rotating handle.

[0008] Further, the base mainly serves as support and fixation, and stainless steel is used as the preparation material to ensure stable operation of the device.

[0009] Further, the support seat mainly serves as support and stability to ensure normal operation of other components in the second part, and the size is determined by the outer diameter of the coil chuck.

[0010] Further, the bolt is used for connection between the support seat and the coil chuck, and mainly serves as fixation.

[0011] Further, the coil chuck is selected from acrylic plates to prevent contact friction from damaging superconducting tapes, and the size is determined according to the predetermined number of turns, which can be stably controlled and transmitted at a certain speed through the servo system, and is used for paying off and taking up the wire.

[0012] Further, the servo motor is selected from AC servo motors, which can provide the required tension for taking up and paying off the REBCO tape through stable operation.

[0013] Further, the placement plate is used for placing the servo motor, and the relative positions of the placement plates of the paying-off part and the taking-up part are symmetrically installed to ensure the balance of the device.

[0014] Further, the positioning block mainly serves as support and fixation, and the size is controlled to ensure the overall height of the guide structure.

[0015] Further, the support sheet metal mainly serves as positioning and support connection, and cooperates with the positioning block to determine the height of the guide structure.

[0016] Further, the guide wheel is selected from epoxy resin to prevent contact friction from damaging superconducting tapes, and can position and guide the REBCO tape to achieve efficient and stable transmission.

[0017] Further, the guide column is fixed at both ends with the support sheet metal, and then cooperates with the guide wheel to ensure stable transmission of the REBCO tape.

[0018] Further, the workbench is made of high-quality stainless steel, and a layer of soft material (such as epoxy resin) needs to be fixed on the working surface of the workbench.

[0019] Furthermore, the placement plate is used to place the servo motor that controls the grating ruler, and its specific size is determined according to the size of the servo motor.

[0020] Furthermore, the guide wheels are made of epoxy resin to prevent contact friction from damaging the superconducting tape; two guide wheels are placed at each end of the worktable, and their positioning is adjusted according to the tape width to ensure that the tape does not shift during the cutting process.

[0021] Furthermore, the diamond cutting tool is selected from high wear-resistant and high-hardness diamond cutting tools. By processing the diamond cutting tool head, micron-level grooves can be cut on the surface of REBCO strip, thereby preparing REBCO multi-core strip.

[0022] Furthermore, the fixed tool block is mainly used for fixing diamond tools, and is connected to the lead screw to control the lifting direction of the tool.

[0023] Furthermore, the lead screw has a micron-level size and can work in conjunction with the rotary handle to control the lifting and lowering of the fixed tool block and the diamond tool.

[0024] Furthermore, the support frame is mainly used to assist in the lifting of the tool and the installation of the grating ruler, and the specific height is determined according to the length of the lead screw.

[0025] Furthermore, the grating ruler uses a micron-level detection system to precisely monitor the descent dimension of the cutting tool and cut REBCO multi-core strips with the same depth.

[0026] Furthermore, the rotary handle and the lead screw are precisely matched to control the up and down movement of the fixed tool block, thereby controlling the cutting depth of the strip by the diamond tool to be at the micrometer level.

[0027] According to another aspect of the present invention, a method for mechanically cutting REBCO multicore strip is provided, comprising the steps of:

[0028] 1) Assembly of the device: Install the four parts of the device in sequence, then connect the power supply and check whether the operation of each servo motor is normal;

[0029] 2) Trial conveying of strip: First, the strip to be cut is drawn out from the feed chuck, passes through the guide wheels of the guide structure, and then positioned on the worktable according to the width of the strip. It is then drawn out from the guide wheels on the other side of the guide structure and finally stored in the take-up chuck.

[0030] 3) Tension and size adjustment: The running speed and tension are adjusted by the servo motor in the take-up and pay-off structure; the position of the cutter is adjusted by the rotation handle and the lead screw, and the position change is monitored in real time by a micron-level grating ruler.

[0031] 4) Cutting of the tape: the device runs according to the set parameters, and then cuts according to the requirements to prepare the multi-core tape with excellent performance;

[0032] 5) Real-time monitoring of the cutting state: the cutting state of the cutting device can be observed in real time, and the quality of the processed tape can be supervised.

[0033] Further, the device comprises a first part base, a second part wire feeding structure, a third part guide structure, and a fourth part processing structure, and the third part guide structure and the second part wire feeding structure are sequentially installed. After installation, the power supply is connected, and the operation of each servo motor is detected.

[0034] Further, the tape to be cut is drawn out from the wire feeding reel, passes through the guide wheels of the guide structure, is positioned on the workbench according to the width of the tape, is drawn out from the guide wheels on the other side of the guide structure, and is finally collected in the wire collecting reel.

[0035] Further, the servo motors in the wire feeding and wire collecting structure adjust the running speed and determine the tension size; the position of the cutter is adjusted by rotating the handle and the screw rod, and the position change is monitored in real time by the micron-level grating ruler to ensure the cutting depth requirement.

[0036] Further, the REBCO tape to be cut has a thickness of about 0.1 mm. Thin tapes will not degrade in performance due to small bending, and are easy to process. For example, the ST-4-E model tape produced in Shanghai has a width of 4 mm and a thickness of 0.09 mm. The substrate thickness is about 50 μm, the buffer layer thickness is about 0.2 μm, the REBCO superconducting layer is about 1 μm thick, the Ag protective layer is about 1.5 μm thick, and the Cu stabilizing layer is about 20 μm thick.

[0037] Further, the REBCO tape cutting surface is near the superconducting layer, that is, a groove is formed by cutting the Cu stabilizing layer, the Ag protective layer, the superconducting layer, and the buffer layer, thereby obtaining the REBCO multi-core tape.

[0038] Further, the cutting state of the cutting device can be monitored in real time to supervise the quality of the cut tape, and finally the qualified multi-core superconducting tape is sealed with a protective film.

[0039] Advantages:

[0040] The device for preparing REBCO multi-core tapes based on diamond knives in a roll-to-roll manner according to the present application can not only realize the rapid preparation of superconducting multi-core tapes, but also prepare multi-core tapes with uniform cutting depth and width by designing the control system of the diamond and the diamond knives, and the efficiency of preparation is greatly improved and the performance of the multi-core tapes is more excellent. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 The mechanical device for preparing REBCO multi-core tapes in a roll-to-roll manner according to the present application is shown in the overall schematic diagram.

[0042] Figure 2 The first part of the base is shown in the schematic diagram.

[0043] Figure 3 The second part of the wire feeding and winding structure is shown in the schematic diagram.

[0044] Figure 4 The guiding structure is shown in the schematic diagram.

[0045] Figure 5 The processing structure is shown in the schematic diagram. DETAILED DESCRIPTION

[0046] In order to more clearly illustrate the embodiments of the present application or the prior art, the drawings needed in the description of the prior art and the embodiments will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the provided drawings.

[0047] The present application provides a device for preparing REBCO multi-core tapes based on diamond knives in a roll-to-roll manner, as shown in the figure. Figure 1 The device mainly includes four parts: the first part is the base 1; the second part is the wire feeding and winding structure, which includes a support seat 201, a bolt 202, a coil chuck 203, a servo motor 204, and a placement plate 205; the third part is the guiding structure, which includes a positioning block 301, a support sheet metal 302, a guide wheel 303, and a guide column 304; and the fourth part is the processing structure, which includes a workbench 401, a placement plate 402, a guide wheel 403, a diamond knife 404, a fixed knife block 405, a lead screw 406, a support table 407, a grating ruler 408, and a rotating handle 409.

[0048] Figure 2 The first part of the base 1 is shown in the schematic diagram. The base 1 described in the present application mainly plays a supporting and fixing role, and stainless steel is used as the preparation material to ensure the stable operation of the device.

[0049] Figure 3 It is the schematic diagram of the second part of the wire feeding and winding structure in the application; including support seat 201, bolt 202, coil chuck 203, servo motor 204, placement plate 205. The support seat 201 mainly plays a supporting and stabilizing role, ensures the normal operation of other parts of the second part, and the size is determined by the outer diameter of the coil chuck. The bolt 202 is used for the connection of the support seat 201 and the coil chuck 203, mainly plays a fixing role. The coil chuck 203 is used for preventing the destruction of superconducting tapes by contact friction, the selected material is acrylic plate, the size is determined according to the predetermined number of turns, and the transmission can be stably controlled at a certain speed through the servo system, which is used for wire feeding and winding. The servo motor 204 selects an alternating current servo motor, through its stable operation, the required size of the tension can be provided to wind and unwind the REBCO tape. The placement plate 205 is used for placing the servo motor 204, and the relative positions of the placement plates 205 of the wire feeding part and the wire winding part are symmetrically installed to ensure the balance of the device.

[0050] Figure 4 It is the schematic diagram of the guiding structure in the application; including positioning block 301, support sheet metal 302, guide wheel 303, guide column 304. The positioning block 301 mainly plays a supporting and fixing role, and the size is controlled to ensure the overall height of the guiding structure. The support sheet metal 302 mainly plays a positioning and supporting connection role, cooperates with the positioning block 301 to determine the height of the guiding structure. The guide wheel 303 is used for preventing the destruction of superconducting tapes by contact friction, and the selected material is epoxy resin, which can position and guide the REBCO tape and realize efficient and stable transmission. The guide column 304 is fixed at both ends with the support sheet metal 302, and then cooperates with the guide wheel 303 to connect, to ensure the stable transmission of the REBCO tape.

[0051] Figure 5The application discloses a cutting device for REBCO multi-core tape, and belongs to the technical field of REBCO multi-core tape preparation.The cutting device is composed of nine parts, i.e., a workbench 401, a placing plate 402, a guide wheel 403, a diamond cutter 404, a fixed cutter block 405, a lead screw 406, a supporting frame 407, a grating ruler 408 and a rotating handle 409.The workbench 401 is made of high-quality stainless steel, and a layer of soft material (such as epoxy resin) is fixed on the workbench processing surface.The placing plate 402 is used for placing a servo motor for controlling the grating ruler 408, and the size of the placing plate is determined according to the size of the servo motor.The guide wheel 403 is made of epoxy resin and is used for preventing contact friction from damaging the superconducting tape.Two guide wheels 403 are arranged at two ends of the workbench 401, and the positions of the guide wheels are adjusted according to the width of the tape so as to ensure that the tape does not move during the cutting process.The diamond cutter 404 is made of high-wear-resistance and high-hardness diamond cutter, and a diamond cutter head is prepared through processing, so that micron-level grooves can be cut on the surface of the REBCO tape, and then the REBCO multi-core tape can be prepared.The fixed cutter block 405 is mainly used for fixing the diamond cutter 404, and is connected with the lead screw 406 so as to control the lifting direction of the cutter.The size of the lead screw 406 is micron-level, and the lead screw can be used in cooperation with the rotating handle 409 to control the lifting of the fixed cutter block 405 and the diamond cutter 404.The supporting frame 407 is mainly used for cooperating with the lifting of the cutter and the installation of the grating ruler 408, and the height of the supporting frame is determined according to the length of the lead screw 406.The grating ruler 408 is a micron-level detection system, which is used for precisely monitoring the descending size of the cutter, and cutting the REBCO multi-core tape with the same depth.The rotating handle 409 is precisely matched with the lead screw 406, and is used for controlling the up-and-down movement of the fixed cutter block 405, so that the depth of the tape cut by the diamond cutter 404 is micron-level.

[0052] According to another embodiment of the application, a method for preparing REBCO multi-core tape by using the above device is provided, and the method comprises the following steps.

[0053] Step 1. Assembly of the cutting device

[0054] Step 2. Trial conveying of the tape

[0055] Step 3. Adjustment of the tape tension and size

[0056] Step 4. Cutting of the tape

[0057] Step 5. Real-time monitoring of the cutting state.

[0058] Assembly stage of the cutting device: the four parts of the device are installed in sequence, and then the power supply is connected, and the running state of each servo motor is detected.

[0059] The trial conveying stage of the strip: the strip to be cut is first led out from the unwinding chuck, passes through the guide wheels of the guide structure part, is then positioned on the workbench according to the width of the strip, is led out from the guide wheels on the other side of the guide structure part, and is finally received in the winding chuck.

[0060] The tension size and size adjustment stage of the strip: the running speed and tension size are adjusted by the servo motors in the winding and unwinding structure; the position of the cutter is adjusted by the rotary handle and the screw rod, and the position change is monitored in real time by the micron-level grating ruler.

[0061] The cutting stage of the strip: the device is operated according to the set parameters, and is then cut according to the requirements, so as to prepare the multi-core strip with excellent performance.

[0062] Real-time monitoring of the cutting state: the cutting state of the cutting device can be observed in real time, and the quality of the processed strip can be supervised.

[0063] The above is only a conceptual diagram of one specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, and any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application is included in the protection scope of the claims of the present application.

Claims

1. An apparatus for preparing REBCO multi-core strip based on roll-to-roll diamond tools, characterized in that, The device comprises four parts: The first part is the base, which serves to support and fix the structure. The second part is the wire feeding and take-up structure, including a support base, bolts, a coil chuck, a servo motor, and a placement plate. The support base mainly serves to support and stabilize the wire, ensuring the normal operation of all components in the second part. The bolts are used to connect the support base and the coil chuck. The coil chuck is made of acrylic sheet to prevent contact friction from damaging the superconducting tape. Its dimensions are determined according to the predetermined number of turns. It can be stably controlled and transmitted at a certain speed by a servo system for wire feeding and take-up. The servo motor is an AC servo motor, and the placement plate is used to hold the servo motor. The third part is the guide structure, which includes positioning blocks, supporting sheet metal, guide wheels, and guide pillars; The fourth part is the machining structure, including the worktable, placement plate, guide wheel, diamond tool, fixed tool block, lead screw, support table, grating ruler, and rotating handle; The second, third, and fourth parts are all fixed to the first part, i.e., the base. The diamond cutting tool, through machining to obtain a diamond cutting head, can cut micron-level grooves on the surface of REBCO strip, thereby preparing REBCO multi-core strip; the fixed tool block is mainly used to fix the diamond cutting tool, and is connected to the lead screw to control the lifting direction of the tool; the lead screw has a standard size at the micron level, and works with the rotating handle to control the lifting of the fixed tool block and the diamond cutting tool; The support platform is mainly used to assist in the lifting of the cutting tool and the installation of the grating ruler; the grating ruler uses a micron-level detection system to precisely monitor the descent of the cutting tool and cut REBCO multi-core strips with the same depth; the rotating handle and the lead screw are precisely matched to control the up and down movement of the fixed cutting tool block, thereby controlling the cutting depth of the diamond tool to the micron level. The REBCO tape cutting surface is a near-superconducting layer, that is, a groove is formed by cutting the Cu stabilizing layer, Ag protective layer, superconducting layer and buffer layer to obtain REBCO multi-core tape. The substrate thickness is 50 μm, the buffer layer thickness is 0.2 μm, the REBCO superconducting layer is 1 μm thick, the Ag protective layer is 1.5 μm thick, and the Cu stabilizing layer is 20 μm thick.

2. The apparatus for preparing REBCO multi-core strip by rolling diamond tools as described in claim 1, characterized in that, The servo motor is an AC servo motor, which provides the required tension for winding and unwinding REBCO tape through its smooth operation. The placement plate is used to place the servo motor, and the placement plates of the wire feeding section and the wire take-up section are installed symmetrically to ensure the balance of the device.

3. The apparatus for preparing REBCO multi-core strip by rolling diamond tools as described in claim 1, characterized in that, The positioning block mainly serves to support and fix the structure, and the overall height of the guide structure is ensured by controlling the size standard. The supporting sheet metal serves to position and support the connection, and works with the positioning block to determine the height of the guide structure; The guide wheel is made of epoxy resin to prevent contact friction from damaging the superconducting tape. It is used to position and guide the REBCO tape to achieve stable transmission. The guide post is fixed at both ends to the supporting sheet metal, and then connected to the guide wheel to ensure stable REBCO strip conveying.

4. The apparatus for preparing REBCO multi-core strip by rolling diamond tools as described in claim 1, characterized in that, The workbench is made of stainless steel and a protective material needs to be fixed on the machined surface of the workbench. The placement plate is used to place the servo motor that controls the grating ruler; The guide wheels are made of epoxy resin to prevent contact friction from damaging the superconducting tape. Two guide wheels are placed at each end of the worktable, and their positioning is adjusted according to the width of the tape to ensure that the tape does not shift during the cutting process.

5. A method for preparing REBCO multicore tape using the apparatus of any one of claims 1-4, characterized in that, Including the following steps: 1) Assembly of the device: Install the four parts of the device in sequence, then connect the power supply and check whether the operation of each servo motor is normal; 2) Trial conveying of strip: First, the strip to be cut is drawn out from the feed chuck, passes through the guide wheels of the guide structure, and then positioned on the worktable according to the width of the strip. It is then drawn out from the guide wheels on the other side of the guide structure and finally stored in the take-up chuck. 3) Tension and size adjustment: The running speed and tension are adjusted by the servo motor in the take-up and pay-off structure; the position of the cutter is adjusted by the rotation handle and the lead screw, and the position change is monitored in real time by a micron-level grating ruler. 4) Strip cutting: The device operates according to the set parameters and then cuts according to the required requirements to prepare multi-core strips; 5) Real-time monitoring of cutting status: Real-time observation of the cutting status of the cutting device to supervise the quality of the processed strip.

6. The method as described in claim 5, characterized in that, The device is installed in sequence as follows: the first part is the base; the second part is the wire feeding structure; the third part is the guiding structure; the fourth part is the processing structure; the third part is the guiding structure and the second part is the wire take-up structure. After installation, the power is turned on and the operation of each servo motor is checked to see if it is normal.

7. The method as described in claim 5, characterized in that, The strip to be cut is drawn out from the feed chuck, passes through the guide wheels of the guide structure, is then positioned on the worktable according to the strip width, is drawn out from the guide wheels on the other side of the guide structure, and finally stored in the take-up chuck.

8. The method as described in claim 5, characterized in that, The servo motors in the take-up and unload structures adjust the running speed and determine the tension; the position of the cutter is adjusted by rotating the handle and the lead screw, and the position change is monitored in real time by a micron-level grating ruler to ensure the required cutting depth.

9. The method as described in claim 5, characterized in that, The REBCO tape cutting surface is a near-superconducting layer, that is, a groove is formed by cutting the Cu stabilizing layer, Ag protective layer, superconducting layer and buffer layer to obtain REBCO multi-core tape.

10. The method as described in claim 5, characterized in that, The cutting status of the cutting device can be monitored in real time to supervise the quality of the cut strip. Finally, the qualified multi-core superconducting strip is sealed with a protective film.

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