Special cutter and method for machining special-shaped groove in plate type fuel element follower assembly

Abstract

The invention provides a special cutter and method for machining a special-shaped groove in a plate type fuel element follower assembly. The special cutter for machining the special-shaped groove in the plate type fuel element follower assembly comprises a milling cutter edge and a milling cutter handle. The number of the milling cutter edges is three, and the helical angle of the milling cutter edges is 60 degrees. And the part with the diameter of 25mm of the milling cutter edge has the width of 13mm. And the clearance diameter of the milling cutter handle is 12mm. The special tool is modified, and the special tool is designed and manufactured according to the structure and the size of the special-shaped groove. A horizontal milling machine or a machining center is used, according to the structure and the size of the follower special-shaped groove, the diameter of a milling blade of a special tool is combined, CAD software is adopted to accurately calculate the tool running path, interference between the tool and the follower assembly is avoided, numerical control machining transformation of the follower assembly special-shaped groove is achieved, the machining technology is greatly simplified, and the machining efficiency is improved. The machining precision and reliability of the follower assembly are improved, the machining time of each set of follower special-shaped groove is shortened to about 1 hour from original 5-6 hours, and contribution is made to improvement of the plate type fuel assembly follower batch production technology.

Description

Technical Field

[0001] The present application belongs to the technical field of special-shaped groove processing, and specifically relates to a special tool and method for processing special-shaped grooves in a plate-type fuel element follower assembly. Background Art

[0002] The plate-type fuel element follower assembly consists of a fuel plate, a side plate, an upper connecting plate and a lower connecting plate. The plate-type fuel element follower assembly needs to be used in conjunction with the control rod assembly. In order to facilitate the connection and clamping of the operating mechanism, refer to Figure 1 A special groove is designed in the square space of the upper component of the follower component 1. The special groove is four arc-shaped inner holes (see Figure 1 , 2 I-type arc grooves 1a, 2 II-type arc grooves 1b). The two I-type arc grooves 1a and the two II-type arc grooves 1b of the follower assembly 1 are respectively centrally symmetrical structures and are located on the opposite sides of the inner wall of the fuel square assembly.

[0003] At present, in order to realize the machining of the special groove in the follow-up fuel assembly 1, reference Figures 2 to 4 One end of the crank rocker transmission device 22 is installed on the main shaft of the horizontal milling machine 21, and the other end is installed on the support frame of the horizontal milling machine 21. At the same time, the single-tooth milling cutter 23 is also installed on the support frame of the horizontal milling machine 21. The main shaft of the horizontal milling machine 21 rotates, driving the single-tooth milling cutter 23 at the other end of the crank rocker transmission device 22 to make a pendulum motion. The single-tooth milling cutter 23 rotates within a certain angle to mill and form a special groove in the follower body component 1, avoiding the problem that the arc groove processing on both sides of the square component is interfered by the inner walls of the other two sides, and realizing the mechanical processing of the special groove in the follower fuel component 1.

[0004] However, this special groove processing requires multiple feeding, tool changing and measuring. This operation method is complicated and has high requirements for operators. It takes 5 to 6 hours to process each set of components, which consumes a lot of physical strength and energy of the operators, and there is a high risk of processing quality. Summary of the invention

[0005] In view of this, the embodiments of the present application are dedicated to providing a special tool and method for machining special-shaped grooves in a plate-type fuel element follower assembly. By modifying the special tool, the machining of the special-shaped grooves is achieved, greatly simplifying the machining process.

[0006] The first aspect of the present application provides a special tool for machining a special groove in a plate-type fuel element follower assembly, and the special tool for machining a special groove in a plate-type fuel element follower assembly comprises a milling cutter blade and a milling cutter handle. The milling cutter blade has three edges, and the helix angle of the milling cutter blade is 60°. The milling cutter blade has a diameter of 25 mm and a width of 13 mm, and the clearance diameter of the milling cutter handle is 12 mm.

[0007] The second aspect of the present application provides a method for processing a special-shaped groove in a follower assembly of a plate-type fuel element, and the method for processing a special-shaped groove in a follower assembly of a plate-type fuel element includes workpiece clamping and alignment, I-type arc groove machining coordinate determination, and I-type arc groove machining implementation. Workpiece clamping and alignment: Workpiece clamping and alignment: Install a precision flat-nose pliers on the workbench of a horizontal CNC milling machine, and align the precision flat-nose pliers so that the jaws of the precision flat-nose pliers are parallel to the Y-axis of the machine tool. The follower assembly is clamped on the precision flat-nose pliers, and an edge finder is used to detect and align the workpiece, with the center of one end of the follower assembly as the machining zero point. The machining coordinates of the I-type arc groove are determined: the machining coordinates of the I-type arc groove include points o1, a1, b1, c1 and d1. Points o1, a1, b1, c1 and d1 are all in the same plane. The distance between the plane and the end face is the distance between the I-type arc groove and the end face. Point o1 is the center position of the inner cavity cross section of the follower assembly. Point a1 is the milling start position simulated by the CAD software based on the diameter of the special tool for machining the special groove in the follower assembly of the plate-type fuel element provided in the first aspect of the present application and the first arc groove starting point of the I-type arc groove. Point b1 is the milling end position simulated by the CAD software based on the diameter of the special tool and the first arc groove end point of the I-type arc groove. Point c1 is the milling start position simulated by the CAD software based on the diameter of the special tool and the second arc groove starting point of the I-type arc groove. Point d1 is the milling end position simulated by the CAD software based on the diameter of the tool and the second arc groove end point of the I-type arc groove. I-type arc groove processing implementation: According to the coordinates calculated by the CAD software, a CNC program is compiled to mill the I-type arc groove, and the processing is carried out according to the first tool path. The first tool path is to extend the special tool for processing the special groove in the plate-type fuel element follower assembly from the follower assembly end surface processing zero point to point o1. The special tool rotates at high speed and moves in a straight line to point a1 to start rough milling, and then moves from point a1 to point b1 according to the arc, and then moves to point c1 according to the straight line trajectory, and from point c1 to point d1 according to the arc, and after the rough milling is completed. Then the fine processing is completed by d1-a1-b1-c1-d1. After completion, the tool returns to point o1, and finally the special tool withdraws to a safe distance outside the follower assembly according to the program to complete the processing of the I-type arc groove.

[0008] In a specific embodiment of the present application, the alignment accuracy of the precision flat-nose pliers is controlled within 0.02 mm.

[0009] In a specific embodiment of the present application, the method for processing the special-shaped groove in the plate-type fuel element follower assembly also includes determining the machining coordinates of the type II arc groove and implementing the machining of the type II arc groove.

[0010] Determination of machining coordinates of type II arc groove: The machining coordinates of type II arc groove include o2, a2, b2, c2 and d2. Points o2, a2, b2, c2 and d2 are all in the same plane, and the distance between the plane and the end face is the distance between the type II arc groove and the end face. Point o2 is the center position of the inner cavity section of the follower component; point a2 is the milling start position simulated by the CAD software based on the diameter of the special tool and the first arc groove starting point of the type II arc groove; point b2 is the milling end position simulated by the CAD software based on the diameter of the special tool and the first arc groove end point of the type II arc groove; point c2 is the milling start position simulated by the CAD software based on the diameter of the special tool and the second arc groove starting point of the type II arc groove; point d2 is the milling end position simulated by the CAD software based on the diameter of the special tool and the second arc groove end point of the type II arc groove.

[0011] Implementation of Type II arc groove processing: According to the coordinates calculated by the CAD software, a milling program is compiled, and the Type II arc groove is processed according to the second tool path. The second tool path is that the special tool extends from the zero point of the end face processing of the follower component to point o2. The special tool rotates at high speed and moves in a straight line to point a2 to start rough milling. From point a2, it moves to point b2 along an arc, and then moves to point o2 along a straight line trajectory, and then moves to point c2, and then moves to point d2 along an arc, and returns to point o2 to complete the rough processing, and then completes the fine processing by o2-a2-b2-c2-d2. After completion, the special tool returns to point o2, and finally the special tool withdraws to a safe distance outside the follower component according to the program to complete the processing of Type II arc groove.

[0012] The third aspect of the present application provides a control method for processing special grooves in a follower assembly of a plate-type fuel element, and the control method for processing special grooves in a follower assembly of a plate-type fuel element comprises: obtaining the processing coordinates of an I-type arc groove, the processing coordinates of the I-type arc groove include points o1, a1, b1, c1 and d1, points o1, a1, b1, c1 and d1 are all in the same plane, the distance between the plane and the end face is the distance between the I-type arc groove and the end face, point o1 is the center position of the inner cavity cross section of the follower assembly, point a1 is the diameter of a special tool for processing special grooves in a follower assembly of a plate-type fuel element according to claim 1 and the milling start position of the first arc groove starting point of the I-type arc groove simulated by the CAD software, point b1 is the milling end position simulated by the CAD software according to the diameter of the special tool and the first arc groove end point of the I-type arc groove, and point c1 is the root The milling start position is simulated by the CAD software according to the diameter of the special tool and the starting point of the second arc groove of the I-type arc groove, and point d1 is the milling end position simulated by the CAD software according to the diameter of the tool and the end point of the second arc groove of the I-type arc groove; processing is performed according to the first tool path, and the first tool path is to extend the special tool for processing the special groove in the follower assembly of the plate-type fuel element from the end surface processing zero point of the follower assembly to point o1, and the special tool rotates at high speed while moving in a straight line to point a1 to start rough milling, and moves from point a1 to point b1 according to the arc, and then moves to point c1 according to the straight line trajectory, and moves from point c1 to point d1 according to the arc. After completing rough milling, fine processing is completed by d1-a1-b1-c1-d1. After completion, the tool returns to point o1, and finally the special tool withdraws to a safe distance outside the follower assembly according to the program to complete the processing of the I-type arc groove.

[0013] The fourth aspect of the present application provides a control method for processing special grooves in a follower assembly of a plate-type fuel element, and the control method for processing special grooves in a follower assembly of a plate-type fuel element comprises: obtaining the processing coordinates of a type II arc groove, the processing coordinates of the type II arc groove include points o2, a2, b2, c2 and d2, points o2, a2, b2, c2 and d2 are all in the same plane, the distance between the plane and the end face is the distance between the type II arc groove and the end face, point o2 is the center position of the inner cavity cross section of the follower assembly, point a2 is the milling start position simulated by the CAD software according to the diameter of the special tool and the first arc groove starting point of the type II arc groove, point b2 is the milling end position simulated by the CAD software according to the diameter of the special tool and the first arc groove end point of the type II arc groove, point c2 is the milling end position simulated by the CAD software according to the diameter of the special tool and the first arc groove end point of the type II arc groove, and point The starting point of the second arc groove of the groove is the milling start position simulated by the CAD software, and point d2 is the milling end position simulated by the CAD software according to the diameter of the special tool and the end point of the second arc groove of the type II arc groove; the type II arc groove is processed according to the second tool path, and the second tool path is that the special tool extends from the end face processing zero point of the follower body component to point o2, and the special tool rotates at high speed while moving in a straight line to point a2 to start rough milling, and moves from point a2 to point b2 along the arc, and then moves to point o2 along a straight line trajectory, and then moves to point c2, and then moves to point d2 according to the arc, and retreats to point o2 to complete the rough processing, and then completes the fine processing by o2-a2-b2-c2-d2. After completion, the special tool returns to point o2, and finally the special tool withdraws to a safe distance outside the follower body component according to the program to complete the processing of the type II arc groove.

[0014] The beneficial effect of the technical solution of this application is that after precise analysis and calculation, a special tool is designed and manufactured according to the structure and size of the special groove. Using a horizontal milling machine or machining center, according to the structure and size of the follower special groove, combined with the milling blade diameter of the special tool, the tool running path is accurately calculated using CAD software, avoiding the interference between the tool and the follower assembly, and realizing the transformation of the follower assembly special groove to CNC machining, greatly simplifying the machining process, and improving the machining accuracy and reliability of the follower assembly. The machining time of each set of follower special grooves is reduced from the original 5 to 6 hours to about 1 hour, which has contributed to the improvement of the key machining technology of the follower of the plate-type fuel assembly of the research experimental reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Shown is a schematic structural diagram of a plate-type fuel element follower assembly.

[0016] Figure 2 Shown is a structural front view corresponding to a method for machining a special-shaped groove in a plate-type fuel element follower assembly.

[0017] Figure 3 Shown Figure 2 A structural side view corresponding to a method for machining a special-shaped groove in a plate-type fuel element follower assembly is shown.

[0018] Figure 4 Shown Figure 2 A schematic diagram of the tool and milling used in a method for machining a special-shaped groove in a plate-type fuel element follower assembly is shown.

[0019] Figure 5 Shown is a schematic structural diagram of a special tool for machining special-shaped grooves in a plate-type fuel element follower assembly provided in one embodiment of the present application.

[0020] Figure 6 Shown is a physical diagram of a special tool for machining special-shaped grooves in a plate-type fuel element follower assembly provided in one embodiment of the present application.

[0021] Figure 7 Shown Figure 6 Reference diagram of the state in which the special tool of the illustrated embodiment is clamped on the BT50 tool holder.

[0022] Figure 8 Shown is a schematic diagram corresponding to a method for processing a special-shaped groove in a plate-type fuel element follower assembly provided in one embodiment of the present application.

[0023] Fig. 9 Shown is a physical picture of a horizontal CNC milling machine and a clamping tool provided in one embodiment of the present application.

[0024] Fig.10 Shown is a schematic diagram of an I-type arc groove processing process provided in an embodiment of the present application.

[0025] Fig.11 Shown is a schematic diagram of a Type II arc groove machining process provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0027] Since the I-type arc groove 1a is located at the end face of the follower assembly 1, only the diameter of the tool needs to be considered during tool processing, without considering the clearance size of the tool handle and the milling edge width of the tool. The two II-type arc grooves 1b are two centrally symmetrical structures on the inner wall of the inner side plate of the follower assembly 1, and the positions of the arc grooves and the rectangular holes in the structure are not on the axis.

[0028] At least one embodiment of the present application provides a special tool for machining a special groove in a plate-type fuel element follower assembly, referring to Figure 5 The special tool 3 for machining the special groove in the plate-type fuel element follower assembly includes a milling cutter blade 31 and a milling cutter handle 32. The milling cutter blade 31 has three edges, and the helix angle of the milling cutter blade 31 is 60°. The diameter of the milling cutter blade 31 is 25 mm, and a 13 mm width is reserved. The clearance diameter of the milling cutter handle 32 is 12 mm. The special tool can be clamped by a BT50 handle and installed on a horizontal CNC milling machine or a machining center for processing.

[0029] It should be noted that the milling blade 31 of the special tool can be modified from a Φ25mm high-speed steel flat-bottom end mill. Since the width of the II-type arc groove 1b is 13mm, the 25mm diameter portion of the milling blade 31 is set to have a 13mm width, and the 13mm width dimension tolerance needs to be determined based on the milling test results. The milling shank 32 is ground to a clearance diameter of 12mm, which can meet the processing strength and processing size, and does not interfere with the components during the processing process.

[0030] After careful study, it was found that in order to increase the surface quality of arc groove processing, the rigidity of the tool must be improved and the tool diameter must be increased as much as possible. In the embodiment of the present application, the tool path is simulated by calculation and CAD drawing to verify whether there is interference. The tool is milled to the limit position and 0.64mm is reserved. Under the premise of ensuring that no interference occurs during the processing, the diameter of the special tool milling blade 31 is determined to be 25mm and the clearance diameter of the milling cutter handle 32 is determined to be 12mm. The actual picture of the special tool 3 for processing the special groove in the plate-type fuel element follower assembly is referenced Figure 6 The special tool 3 for machining the special groove in the plate-type fuel element follower assembly is clamped on the BT50 tool holder. Figure 7 .

[0031] At least one embodiment of the present application further provides a method for processing a special-shaped groove in a plate-type fuel element follower assembly, Figure 8 The method for processing the special groove includes the following steps.

[0032] S1: Workpiece clamping and alignment. Install the precision flat-nose pliers on the workbench of the horizontal CNC milling machine and align the precision flat-nose pliers so that the jaws of the precision flat-nose pliers are parallel to the Y-axis of the machine tool. Clamp the follower assembly onto the precision flat-nose pliers, use the edge finder to detect and align the workpiece, and take the center of one end of the follower assembly as the processing zero point.

[0033] It should be noted that the positions of the machine tool 81 and the horizontal CNC milling machine table 82 are set with reference to Figure 8 . Reference pictures of horizontal CNC milling machine and clamping fixture Fig. 9 .

[0034] In at least one embodiment of the present application, the alignment accuracy of the precision flat-nose pliers is controlled within 0.02 mm.

[0035] S2: Determination of the machining coordinates of the I-type arc groove. The machining coordinates of the I-type arc groove include point o1, point a1, point b1, point c1 and point d1. Point o1, point a1, point b1, point c1 and point d1 are all in the same plane. The distance from the plane to the end face is the distance from the I-type arc groove to the end face. Point o1 is the center position of the inner cavity cross section of the follower component. Point a1 is the milling start position simulated by the CAD software based on the diameter of the special tool and the first arc groove starting point of the I-type arc groove. Point b1 is the milling end position simulated by the CAD software based on the diameter of the special tool and the first arc groove end point of the I-type arc groove. Point c1 is the milling start position simulated by the CAD software based on the diameter of the special tool and the second arc groove starting point of the I-type arc groove. Point d1 is the milling end position simulated by the CAD software based on the diameter of the tool and the second arc groove end point of the I-type arc groove.

[0036] S3: Implementation of I-type arc groove processing. According to the coordinates calculated by the CAD software, a CNC program is compiled to mill the I-type arc groove, and the processing is performed according to the first tool path. The first tool path is to extend the special tool for processing the special groove in the follower assembly of the plate-type fuel element from the end surface processing zero point of the follower assembly to point o1. The special tool rotates at high speed and moves in a straight line to point a1 to start rough milling, and then moves from point a1 to point b1 according to the arc, and then moves to point c1 according to the straight line trajectory, and from point c1 to point d1 according to the arc, and completes the rough milling. Then, the fine processing is completed by d1-a1-b1-c1-d1. After completion, the tool returns to point o1, and finally the special tool withdraws to a safe distance outside the follower assembly according to the program to complete the processing of the I-type arc groove.

[0037] First tool path A Fig.10 .

[0038] According to the technical solution provided in the embodiment of the present application, a horizontal CNC milling machine or a horizontal machining center is used for processing, and a precision flat-nose pliers is used for clamping. A special tool is designed and manufactured according to the structure and size of the special-shaped slot, and a process scheme and processing route are designed. The special-shaped slot can be processed in the square hole space of the follower component using a CNC program. Universal processing equipment, precision flat-nose pliers, and end mills are used. After precise analysis and calculation, only the special tool is modified to realize the processing of the special-shaped slot, which greatly simplifies the processing technology. In addition, the embodiment of the present application realizes the CNC processing of the special-shaped slot, which is simple to operate, has a small possibility of misoperation compared to manual operation, is dimensionally stable, simple and reliable to operate, and has low quality risk.

[0039] In at least one embodiment of the present application, the method for processing the special-shaped groove in the plate-type fuel element follower assembly also includes S4 and S5.

[0040] S4: Determination of machining coordinates of type II arc groove. The machining coordinates of type II arc groove include points o2, a2, b2, c2 and d2. Points o2, a2, b2, c2 and d2 are all in the same plane, and the distance between the plane and the end face is the distance between the type II arc groove and the end face. Point o2 is the center position of the inner cavity cross section of the follower component; point a2 is the milling start position simulated by the CAD software based on the diameter of the special tool and the first arc groove starting point of the type II arc groove; point b2 is the milling end position simulated by the CAD software based on the diameter of the special tool and the first arc groove end point of the type II arc groove; point c2 is the milling start position simulated by the CAD software based on the diameter of the special tool and the second arc groove starting point of the type II arc groove; point d2 is the milling end position simulated by the CAD software based on the diameter of the special tool and the second arc groove end point of the type II arc groove.

[0041] S5: Implementation of type II arc groove processing. According to the coordinates calculated by the CAD software, a milling program is compiled, and type II arc grooves are processed according to the second tool path. The special tool extends from the end face processing zero point of the follower component to point o2. The special tool rotates at high speed and moves in a straight line to point a2 to start rough milling. From point a2, it moves to point b2 along the arc, then moves to point o2 along the straight line trajectory, then moves to point c2, and then moves to point d2 along the arc, and returns to point o2 to complete the rough processing. Then, fine processing is completed by o2-a2-b2-c2-d2. After completion, the special tool returns to point o2. Finally, the special tool withdraws to a safe distance outside the follower component according to the program to complete the processing of type II arc grooves.

[0042] The second tool path B is shown in Fig.11 .

[0043] According to the technical solution provided in the embodiment of the present application, on a horizontal CNC milling machine or a horizontal machining center equipment, a CNC program is compiled to avoid workpiece interference and complete the processing of two arc groove structures (i.e., Type I arc groove and Type II arc groove) at one time, with high processing efficiency, which is reduced from the original processing time of 6 hours for one set of components to 1 hour.

[0044] At least one embodiment of the present application further provides a method for controlling the processing of special-shaped grooves in a plate-type fuel element follower assembly. The method for controlling the processing of special-shaped grooves in a plate-type fuel element follower assembly includes steps S10 and S20.

[0045] S10: Obtaining the I-type arc groove processing coordinates. The I-type arc groove processing coordinates include o1 point, a1 point, b1 point, c1 point and d1 point, o1 point, a1 point, b1 point, c1 point and d1 point are all in the same plane, the distance between the plane and the end face is the distance between the I-type arc groove and the end face, o1 point is the center position of the inner cavity cross section of the follower assembly, a1 point is the diameter of the special tool for processing the special groove in the plate-type fuel element follower assembly according to claim 1 and the milling start position simulated by the CAD software at the first arc groove starting point of the I-type arc groove, b1 point is the milling end position simulated by the CAD software according to the diameter of the special tool and the first arc groove end point of the I-type arc groove, c1 point is the milling start position simulated by the CAD software according to the diameter of the special tool and the second arc groove start point of the I-type arc groove, and d1 point is the milling end position simulated by the CAD software according to the diameter of the tool and the second arc groove end point of the I-type arc groove.

[0046] S20: Processing is performed according to the first tool path. The first tool path is to extend the special tool for processing the special groove in the follower assembly of the plate-type fuel element from the follower assembly end surface processing zero point to point o1. The special tool rotates at high speed and moves in a straight line to point a1 to start rough milling. From point a1, it moves along an arc to point b1, and then moves along a straight line trajectory to point c1. From point c1, it moves along an arc to point d1. After rough milling is completed, fine machining is completed by d1-a1-b1-c1-d1. After completion, the tool returns to point o1. Finally, the special tool withdraws to a safe distance outside the follower assembly according to the program to complete the processing of the I-type arc groove.

[0047] At least one embodiment of the present application further provides a method for controlling the processing of special-shaped grooves in a plate-type fuel element follower assembly. The method for controlling the processing of special-shaped grooves in a plate-type fuel element follower assembly includes steps S100 and S200.

[0048] S100: Obtaining the machining coordinates of the type II arc groove. The machining coordinates of the type II arc groove include point o2, point a2, point b2, point c2 and point d2, where point o2, point a2, point b2, point c2 and point d2 are all in the same plane, and the distance between the plane and the end face is the distance between the type II arc groove and the end face, point o2 is the center position of the inner cavity cross section of the follower component, point a2 is the milling start position simulated by the CAD software based on the diameter of the special tool and the first arc groove starting point of the type II arc groove, point b2 is the milling end position simulated by the CAD software based on the diameter of the special tool and the first arc groove end point of the type II arc groove, point c2 is the milling start position simulated by the CAD software based on the diameter of the special tool and the second arc groove starting point of the type II arc groove, and point d2 is the milling end position simulated by the CAD software based on the diameter of the special tool and the second arc groove end point of the type II arc groove.

[0049] S200: Processing type II arc groove according to the second tool path. The second tool path is that the special tool extends from the end face processing zero point of the follower body component to point o2. The special tool rotates at high speed and moves in a straight line to point a2 to start rough milling. It moves from point a2 to point b2 along an arc, and then moves to point o2 along a straight line trajectory, and then moves to point c2, and then moves to point d2 along an arc, and returns to point o2 to complete the rough machining. Then, the fine machining is completed by o2-a2-b2-c2-d2. After completion, the special tool returns to point o2. Finally, the special tool withdraws to a safe distance outside the follower body component according to the program to complete the machining of type II arc groove.

[0050] It should be noted that the combination of the various technical features in the embodiments of the present application is not limited to the combination described in the embodiments of the present application or the combination described in the specific embodiments, and all technical features described in the present application can be freely combined or combined in any way unless there is a contradiction between them.

[0051] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0052] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A special tool for machining special grooves in a plate-type fuel element follower assembly, characterized in that: Including milling cutter blade and milling cutter handle, The milling cutter has three edges, the helix angle of the milling cutter is 60°, the diameter of the milling cutter has a width of 13mm, and the clearance diameter of the milling cutter handle is 12mm.

2. A method for machining a special-shaped groove in a plate-type fuel element follower assembly, characterized in that: include: Workpiece Clamping and alignment: Install precision flat-nose pliers on the workbench of the horizontal CNC milling machine and align the precision flat-nose pliers so that the jaws of the precision flat-nose pliers are parallel to the Y-axis of the machine tool. Clamp the follower assembly onto the precision flat-nose pliers, use the edge finder to detect and align the workpiece, and take the center of one end of the follower assembly as the processing zero point; I-type arc groove processing coordinates are determined: I-type arc groove processing coordinates include o1 point, a1 point, b1 point, c1 point and d1 point, o1 point, a1 point, b1 point, c1 point and d1 point are all in the same plane, the distance between the plane and the end face is the distance between the I-type arc groove and the end face, o1 point is the center position of the inner cavity cross section of the follower assembly, a1 point is the diameter of the special tool for processing the special groove in the plate-type fuel element follower assembly according to claim 1 and the milling start position of the first arc groove starting point of the I-type arc groove simulated by the CAD software, b1 point is the milling end position simulated by the CAD software according to the diameter of the special tool and the first arc groove end point of the I-type arc groove, c1 point is the milling start position simulated by the CAD software according to the diameter of the special tool and the second arc groove starting point of the I-type arc groove, and d1 point is the milling end position simulated by the CAD software according to the diameter of the tool and the second arc groove end point of the I-type arc groove; Implementation of I-type arc groove processing: According to the coordinates calculated by the CAD software, a CNC program is compiled to mill the I-type arc groove, and the processing is performed according to the first tool path. The first tool path is to extend the special tool for processing the special groove in the follower assembly of the plate-type fuel element from the follower assembly end surface processing zero point to point o1. The special tool rotates at high speed and moves in a straight line to point a1 to start rough milling, and moves from point a1 to point b1 along the arc, and then moves to point c1 along a straight line trajectory, and moves from point c1 to point d1 along the arc. After completing rough milling, fine processing is completed by d1-a1-b1-c1-d1. After completion, the tool returns to point o1, and finally the special tool withdraws to a safe distance outside the follower assembly according to the program to complete the processing of the I-type arc groove.

3. The method according to claim 2, characterized in that The accuracy of alignment by precision flat-nose pliers is controlled within 0.02mm.

4. The method according to claim 2, characterized in that: Also includes: The machining coordinates of the II-type arc groove are determined: the machining coordinates of the II-type arc groove include points o2, a2, b2, c2 and d2. Points o2, a2, b2, c2 and d2 are all in the same plane. The distance between the plane and the end face is the distance between the II-type arc groove and the end face. Point o2 is the center position of the inner cavity cross section of the follower component. Point a2 is the milling start position simulated by the CAD software based on the diameter of the special tool and the first arc groove starting point of the II-type arc groove. Point b2 is the milling end position simulated by the CAD software based on the diameter of the special tool and the first arc groove end point of the II-type arc groove. Point c2 is the milling start position simulated by the CAD software based on the diameter of the special tool and the second arc groove starting point of the II-type arc groove. Point d2 is the milling end position simulated by the CAD software based on the diameter of the special tool and the second arc groove end point of the II-type arc groove. Implementation of Type II arc groove processing: According to the coordinates calculated by the CAD software, a milling program is compiled, and the Type II arc groove is processed according to the second tool path. The second tool path is that the special tool extends from the zero point of the end face processing of the follower component to point o2. The special tool rotates at high speed and moves in a straight line to point a2 to start rough milling. From point a2, it moves to point b2 along an arc, and then moves to point o2 along a straight line trajectory, and then moves to point c2, and then moves to point d2 along an arc, and returns to point o2 to complete the rough processing, and then completes the fine processing by o2-a2-b2-c2-d2. After completion, the special tool returns to point o2, and finally the special tool withdraws to a safe distance outside the follower component according to the program to complete the processing of Type II arc groove.

5. A control method for processing a special groove in a plate-type fuel element follower assembly, characterized in that: include: Obtaining the machining coordinates of the I-type arc groove, the machining coordinates of the I-type arc groove include point o1, point a1, point b1, point c1 and point d1, point o1, point a1, point b1, point c1 and point d1 are all in the same plane, the distance between the plane and the end face is the distance between the I-type arc groove and the end face, point o1 is the center position of the inner cavity cross section of the follower assembly, point a1 is the diameter of the special tool for machining the special groove in the follower assembly of the plate-type fuel element according to claim 1 and the milling start position simulated by the CAD software at the first arc groove starting point of the I-type arc groove, point b1 is the milling end position simulated by the CAD software according to the diameter of the special tool and the first arc groove end point of the I-type arc groove, point c1 is the milling start position simulated by the CAD software according to the diameter of the special tool and the second arc groove starting point of the I-type arc groove, and point d1 is the milling end position simulated by the CAD software according to the diameter of the tool and the second arc groove end point of the I-type arc groove; Processing is performed according to the first tool path. The first tool path is to extend the special tool for processing the special groove in the follower assembly of the plate-type fuel element from the follower assembly end surface processing zero point to point o1. The special tool rotates at high speed and moves in a straight line to point a1 to start rough milling, and moves from point a1 to point b1 along an arc, and then moves to point c1 along a straight line trajectory, and moves from point c1 to point d1 along an arc. After completing rough milling, fine processing is completed by d1-a1-b1-c1-d1. After completion, the tool returns to point o1, and finally the special tool withdraws to a safe distance outside the follower assembly according to the program to complete the processing of the I-type arc groove.

6. A control method for processing a special-shaped groove in a plate-type fuel element follower assembly, characterized in that: include: Obtain the machining coordinates of the type II arc groove, which include points o2, a2, b2, c2 and d2. Points o2, a2, b2, c2 and d2 are all in the same plane, and the distance between the plane and the end face is the distance between the type II arc groove and the end face. Point o2 is the center position of the inner cavity cross section of the follower component, point a2 is the milling start position simulated by the CAD software according to the diameter of the special tool and the first arc groove starting point of the type II arc groove, point b2 is the milling end position simulated by the CAD software according to the diameter of the special tool and the first arc groove end point of the type II arc groove, point c2 is the milling start position simulated by the CAD software according to the diameter of the special tool and the second arc groove starting point of the type II arc groove, and point d2 is the milling end position simulated by the CAD software according to the diameter of the special tool and the second arc groove end point of the type II arc groove; Type II arc groove is processed according to the second tool path. The second tool path is that the special tool extends from the end face processing zero point of the follower body component to point o2. The special tool rotates at high speed and moves in a straight line to point a2 to start rough milling. From point a2, it moves to point b2 along an arc, and then moves to point o2 along a straight line trajectory, and then moves to point c2, and then moves to point d2 along an arc, and returns to point o2 to complete the rough processing. Then, the fine processing is completed by o2-a2-b2-c2-d2. After completion, the special tool returns to point o2. Finally, the special tool withdraws to a safe distance outside the follower body component according to the program to complete the processing of type II arc groove.

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