A machining device and method for a nuclear fuel element tooth-shaped part

Abstract

The present application belongs to the technical field of nuclear fuel element manufacturing, and particularly relates to a machining method and device for a tooth-shaped part of a nuclear fuel element. The machining method comprises a general-purpose machine tool, a fixing tool and a machining tool. The general-purpose machine tool is provided with the fixing tool on one side and the machining tool on the other side. The present application has the advantages that the machining and batch production of the tooth-shaped part of the tube-type fuel element are realized through the machining tool and the machining method, the material utilization is improved according to the structural characteristics of the tooth-shaped part, and technical support is provided for the preparation of the fuel element. The special machining tool is designed and manufactured to solve the problem of tooth-shaped groove machining. The existing equipment is modified to have the capability of small-batch production and reduce the investment in equipment. The machining method of the tooth-shaped part is formulated to improve the material utilization.

Description

Technical Field

[0001] This invention belongs to the field of nuclear fuel element manufacturing technology, specifically relating to a method and apparatus for processing toothed parts of nuclear fuel elements. Background Technology

[0002] Some existing nuclear fuel elements adopt a tubular structure, with the fuel element itself being a circular tube. The toothed parts are mainly used to fix and connect the various layers of element tubes. During the assembly process, the element tubes are mainly fixed and connected by the teeth of each layer of these parts. The machining accuracy of the longitudinal dimensions of each layer of teeth in the toothed parts directly affects the assembly accuracy of the entire assembly.

[0003] The raw material for the toothed parts is aluminum. The toothed groove is 1.5mm wide and 22mm deep. Standard end face grooving cutters cannot meet the requirements, and non-standard customized grooving cutters are expensive and have a short lifespan, resulting in high costs.

[0004] Based on the production site conditions, existing equipment was modified, specialized cutting tools were manufactured to meet the machining requirements of the groove shape, and a machining process was developed, improving material utilization. This enabled the machining of this type of toothed part, providing technical support for the research and production of this type of fuel element. Summary of the Invention

[0005] The purpose of this invention is to provide a processing apparatus and method for toothed parts of nuclear fuel elements, which can solve the processing problem of toothed parts of tubular fuel elements.

[0006] The technical solution of the present invention is as follows: A machining apparatus for toothed parts of nuclear fuel elements includes a conventional lathe, a fixed fixture and a machining tool. The fixed fixture is installed on one side of the conventional lathe, and the machining tool is installed on the other side of the conventional lathe.

[0007] The conventional lathe is provided with a large machine tool support plate on one side, and a fixed fixture is installed on the upper part of the machine tool support plate, on which toothed parts are installed.

[0008] The machine tool pallet is equipped with a positioning block on its side, and six positioning posts of different lengths are installed on the positioning block.

[0009] A positioning table is fixed on the other side of the conventional lathe.

[0010] A machining tool is connected to the upper part of the other side of the conventional lathe.

[0011] The machining tool includes a Morse taper shank, a fixing screw, and cutting inserts. The Morse taper shank is connected to the spindle of a conventional lathe, and two cutting inserts are symmetrically fixed to the Morse taper shank using the fixing screw.

[0012] The blade is made of high-speed steel.

[0013] A method for machining a toothed part of a nuclear fuel element includes the following steps:

[0014] Step 1: Complete the milling process before turning the toothed part, machining it into a "cross" structure before turning.

[0015] Step 2: Clamp the semi-finished product, which has been milled into a "cross" structure, onto the fixed fixture;

[0016] Step 3: Insert the corresponding Layer 1 machining tool and rotate out the corresponding positioning pin;

[0017] Step 4: Start the conventional lathe and feed the large pallet using the automatic feed mode. Stop the machine when the positioning block contacts the positioning indicator and reaches a fixed value.

[0018] Step 5: After exiting, replace the two layers of machining tools and positioning pins, and continue machining layer by layer.

[0019] After the tooth shape is machined, it is then divided to produce 4 tooth-shaped parts in one operation;

[0020] The beneficial effects of this invention are as follows: The cutting tools and processing methods provided by this invention enable the machining and mass production of toothed parts for tubular fuel elements. Furthermore, based on the structural characteristics of the toothed parts, material utilization is improved, providing technical support for the preparation of this type of fuel element. A dedicated cutting tool was designed and manufactured, solving the problem of toothed groove machining; existing equipment was modified to enable small-batch production, reducing equipment investment; and a machining method for toothed parts was developed, improving material utilization. Attached Figure Description

[0021] Figure 1 This is a sectional view of a toothed part;

[0022] Figure 2 This is the front view of the toothed part;

[0023] Figure 3 for Figure 1 The C-direction view;

[0024] Figure 4 Step-by-step diagram for toothed parts

[0025] Figure 5 Top view of the machining process diagram for toothed parts

[0026] Figure 6 A schematic diagram of a processing apparatus for a toothed part of a nuclear fuel element provided by the present invention;

[0027] Figure 7 Schematic diagram of machining tools.

[0028] In the diagram: 1. Lathe, 2. Positioning indicator, 3. Positioning block, 4. Machine tool support plate, 5. Fixture, 6. Toothed part, 7. Machining tool, 8. Positioning pin, 9. Fixing screw, 10. Morse taper shank, 11. Insert. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] The present invention provides a method and apparatus for machining toothed parts of nuclear fuel elements. By modifying existing ordinary lathes and designing machining tools and fixtures, the parts can be machined, reducing capital investment.

[0031] Based on the structural characteristics of the toothed part (6 layers of teeth), a set of forming tools (6 pieces) was designed for a conventional lathe to machine the toothed part. During machining, tool setting is frequent and difficult, easily leading to tool collisions, causing serious damage to the tools and affecting the workpiece machining progress. For these reasons, a longitudinal positioner for the conventional lathe was designed and manufactured to reduce tool setting time, protect the tools, improve machining accuracy and labor efficiency, and enable small-batch production.

[0032] This invention uses a conventional lathe as the main equipment, modifying it into a specialized machining device. A special cutting tool is mounted in the lathe spindle to achieve rotary cutting. A fixed fixture is installed on a large pallet to hold the toothed part, and cutting is achieved by moving the pallet. A positioning block is installed on the large pallet of the machine tool and used in conjunction with a positioning gauge to control the cutting depth.

[0033] A machining apparatus for toothed parts of nuclear fuel elements includes a conventional lathe 1, a fixed fixture 5, and a machining tool 7. A large machine tool support plate 4 is provided on one side of the conventional lathe 1, and the fixed fixture 5 is mounted on the upper part of the machine tool support plate 4. The toothed part 6 can be mounted on the fixed fixture 5. A positioning block 3 is mounted on the side end of the machine tool support plate 4. A positioning gauge 2 is fixed on the other side of the lathe 1, and the machining tool 7 is connected to the upper part of the other side of the lathe 1. The machining tool 7 includes a Morse taper shank 10, a fixing screw 9, and inserts 11. The Morse taper shank 10 is connected to the machine tool spindle. Two inserts are symmetrically fixed on the Morse taper shank 10 using the fixing screw 9 to ensure the clamping accuracy of the tool. The inserts 11 are made of high-speed steel. They are first turned and ground into a ring structure according to the inner and outer diameters and depth dimensions of the toothed part, then cut into an arc-shaped structure using wire cutting, and finally the tool back angle is manually ground.

[0034] Among them, the conventional lathe 1 is a C620 conventional lathe. The positioning gauge 2 serves as a display. Since the conventional lathe 1 cannot accurately display the travel value during turning, a dial indicator is used as the positioning gauge 2 and fixed on the conventional lathe 1. The gauge needle points towards the machine tool's large support plate 4. The machine tool's large support plate 4 drives the positioning block 3 to move and press against the gauge needle. After reaching the fixed display travel, turning stops to ensure the machining depth dimension. The positioning block 3 is designed with six positioning pins 8 of different lengths according to the number of teeth of the toothed part. Each requires the use of a corresponding cutting tool. Each cutting tool has different structural dimensions, so the longitudinal feed dimension is also different when machining each layer of teeth. Based on this characteristic, six positioning pins 8 of different lengths are designed and fixed together on the machine tool's large support plate 4. Each positioning pin represents a depth dimension. When machining different teeth, the workpiece is rotated to the corresponding positioning pin for machining. It is used in conjunction with the positioning gauge to ensure the machining depth dimension. The positioning block 3 and the workpiece fixing fixture 5 are both connected to the machine tool's large support plate 4. As the machine tool's large support plate 4 moves, the workpiece moves closer to and away from the cutting tool on the spindle. The fixture 5, fabricated based on the toothed part 6, fixes the part onto the machine tool's large support plate 4, ensuring the part's clamping accuracy. The machining tool 7 includes a Morse taper shank 10, a fixing screw 9, and inserts 11. The Morse taper shank 10 is connected to the machine tool spindle, ensuring the tool's clamping accuracy. The inserts 11 are made of high-speed steel. First, based on the inner and outer diameters and depth of the tooth being machined, they are turned and ground into a ring structure, then wire-cut into an arc-shaped structure, and finally manually ground to create the tool's back angle. The fixing screw 9 symmetrically fixes the two inserts onto the Morse taper shank 10.

[0035] A method for machining a toothed part of a nuclear fuel element includes the following steps:

[0036] Step 1: Depending on the stress of the machining process, in order to ensure machining strength, milling is completed before turning, and a "cross" structure is machined before turning;

[0037] Step 2: Mount the semi-finished product, which has been milled into a "cross" shape, onto the fixed fixture 5.

[0038] Step 3: Insert the corresponding layer 1 machining tool 7 and rotate out the corresponding positioning post 8.

[0039] Step 4: Start the conventional lathe 1 and feed the large pallet using the automatic feed mode. Stop the machine tool 4 when the positioning block 3 contacts the positioning gauge 2 and reaches the fixed value.

[0040] Step 5: After exiting, replace the two layers of machining tools and positioning pin 8 to continue machining layer by layer;

[0041] After machining the tooth shape, it is then divided, which can produce 4 tooth-shaped parts at once, thus improving both processing efficiency and material utilization.

Claims

1. A method for machining a toothed part of a nuclear fuel element, using a machining device for a toothed part of a nuclear fuel element, the device comprising a conventional lathe, a fixed fixture and a machining tool, wherein a large machine tool support is provided on one side of the conventional lathe, and a fixed fixture is installed on the upper part of the large machine tool support, and the toothed part is installed on the fixed fixture. The machine tool pallet is equipped with a positioning block on its side, and six positioning posts of different lengths are installed on the positioning block. A positioning table is fixed on the other side of the conventional lathe. A machining tool is connected to the upper part of the other side of the conventional lathe. The machining tool includes a Morse taper shank, a fixing screw, and cutting inserts. The Morse taper shank is connected to the spindle of a conventional lathe, and two cutting inserts are symmetrically fixed on the Morse taper shank using the fixing screw. The blade is made of high-speed steel. Its features are, Includes the following steps: Step 1: Complete the milling process before turning the toothed part, and machine it into a "cross" structure before turning; Step 2: Clamp the semi-finished product, which has been milled into a "cross" structure, onto the fixed fixture; Step 3: Insert the corresponding Layer 1 machining tool and rotate out the corresponding positioning pin; Step 4: Start the conventional lathe and feed the large pallet using the automatic feed mode. Stop the machine when the positioning block contacts the positioning indicator and reaches a fixed value. Step 5: After exiting, replace the two layers of machining tools and positioning pins to continue machining layer by layer; After the tooth shape is machined, it is then divided, producing 4 tooth-shaped parts in one operation.

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