A method for creating a filament winding mold and manufacturing a filament for an X-ray tube.

Abstract

This invention provides an X-ray tube filament winding mold and a filament manufacturing method. The winding mold includes a first main mold, a second main mold, and a clamping plate. Both the first and second main molds are cylindrical. The front end of the first main mold and the rear end of the second main mold each have two positioning holes. Angular grooves are formed on both sides of the first main mold, symmetrically opposite in direction, with pin holes at the rear of the grooves. Two positioning pins are provided in the two positioning holes at the front end of the first main mold. The front end of the first main mold and the rear end of the second main mold can be connected by the positioning pins. The first and second main molds are fixed together by the clamping plate. Using the filament winding mold, a coil-shaped X-ray tube filament, distinct from a long, spiral filament, can be regularly wound. The filament winding mold has a simple structure, low manufacturing cost, is easy to use, has a high reusability rate, long lifespan, and wide applicability. The wound filament has a small and regular emission surface, resulting in a relatively concentrated spatial distribution of emitted electrons, making it easy to focus and improving the spatial resolution of image reconstruction.

Description

Technical Field

[0001] This invention belongs to the field of electronics and relates to X-ray tubes, specifically to an X-ray tube filament winding mold and filament manufacturing method. Background Technology

[0002] Since its invention, the X-ray tube has garnered significant attention due to its unique physical and chemical effects. Its earliest form can be traced back to the Crookes tube invented by W.K. Röntgen in 1895, widely recognized as the earliest gas-filled X-ray tube. In 1913, W.D. Kurligie invented the vacuum X-ray tube, bringing it to practical use. Through continuous improvement and innovation by scientists, X-ray tubes are now widely used in numerous research and production fields, including life sciences, materials science, industrial flaw detection, and security inspection. For example, X-rays are used for elemental analysis and medical imaging, as well as for non-destructive testing and customs clearance. Currently, the application value and scope of X-rays continue to expand, and the X-ray tube has become an indispensable vacuum electronic device for human scientific research and production.

[0003] The working principle of an X-ray tube can be simply described as follows: electrons emitted from the cathode are accelerated and strike the anode target, generating X-rays. Currently, most commercially available X-ray tubes are thermionic cathode X-ray tubes, using a heated filament as the electron emission source. The filament is usually made of pure tungsten or tungsten alloy wire in a helical structure. This type of filament is long and thin, resulting in a large spatial distribution of emitted electrons, making it difficult to focus and affecting the spatial resolution of image reconstruction. Moreover, the large size of this type of filament makes it difficult to apply to multi-source detection or addressable detection, limiting its application in high-resolution three-dimensional X-ray imaging. Summary of the Invention

[0004] In order to solve the above-mentioned technical problems in the prior art, the present invention provides an X-ray tube filament winding mold and filament manufacturing method, the purpose of which is to standardize and quickly wind coil-shaped X-ray tube filaments.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] An X-ray tube filament winding mold includes a first main mold, a second main mold, and a clamping plate. Both the first and second main molds are cylindrical. The front end of the first main mold and the rear end of the second main mold each have two positioning holes. Angular grooves are formed on both sides of the front end of the first main mold, and the two angular grooves are symmetrically arranged in opposite directions. The rear part of the two angular grooves has a pin hole that penetrates the first main mold for installing a pin. Positioning pins are respectively provided in the two positioning holes at the front end of the first main mold, and the front end of the first main mold and the rear end of the second main mold are connected by positioning pins. The first main mold and the second main mold are fixed together by the clamping plate.

[0007] Furthermore, in the two cylindrical main molds, the diameter of the first main mold is larger than the diameter of the second main mold.

[0008] Furthermore, the clamping plate is a semi-circular groove plate, with the front half of the semi-circular groove plate matching the outer diameter of the second main mold and the rear half matching the outer diameter of the first main mold.

[0009] Furthermore, the first main mold, the second main mold, and the clamping plate are made of molybdenum (Mo1), a metal with a high melting point and a low coefficient of expansion.

[0010] Furthermore, the geometry of the winding mold varies with the thickness of the filament material, the diameter of the disc, and the spacing between the coils.

[0011] This invention utilizes the aforementioned X-ray tube filament winding mold in the winding of filament materials with rectangular or circular cross-sections.

[0012] A method for manufacturing a filament using the above-mentioned X-ray tube filament winding mold specifically includes the following steps:

[0013] S1. The rear end of the first main mold and the front end of the second main mold are respectively clamped in the chuck and tailstock of the horizontal lathe; one of the positioning pins at the front end of the first main mold hooks the filament material, and pulls the two ends of the filament material together to maintain a certain tension;

[0014] S2. Move the lathe tailstock to bring the second main mold closer to the first main mold, slightly rotate the tailstock to match the positioning hole of the second main mold with the positioning pin on the first main mold, clamp the filament material between the first and second main molds, and try to rotate the filament material so that it can move radially along the mold without being clamped, and then fix the lathe tailstock.

[0015] S3. Ignite the natural gas or hydrogen burner and heat the contact area between the mold and the filament material until the filament material turns red-hot, with the temperature at 950±100℃. Then, slowly rotate the lathe chuck counterclockwise so that the entire winding mold rotates with the lathe chuck. As the chuck rotates, the filament material is tightened and fed synchronously, so that the filament material is tightly wound around the gap between the first and second main molds until the mold plate is filled.

[0016] S4. Separate the two leads of the filament material, tighten the hooks and hang them on the groove teeth on both sides of the first main mold, then wrap the filament material around the pin at the tail of the first main mold, and cut off the remaining material;

[0017] S5. Attach the clamping plate to the first and second main molds and bind it with tungsten wire. Remove the bound mold from the lathe and place it in the hydrogen furnace to purge with wet hydrogen. Select a temperature control point within the range of 1400-1800℃ and control the temperature difference within ±10℃. Maintain this temperature for 20 minutes to shape the filament. Cool the temperature down to below 60℃, remove the mold and filament. Heat the filament with a natural gas or hydrogen torch and shape the two leads of the filament with flat-nose pliers. Chemically clean the filament.

[0018] The temperature control point is selected within the range of 1400 to 1800℃, and the temperature difference is controlled by ±10℃ to maintain the shape for 20 minutes. Furthermore, the temperature control point can be adjusted to adjust the filament coil spacing.

[0019] Preferably, the filament material is any one of tungsten or tungsten alloy wire, molybdenum or molybdenum alloy wire, and the filament material has a rectangular or circular cross-section with a cross-sectional area of ​​0.015–0.785 mm². 2 between.

[0020] Preferably, the filament coil spacing is related to the shaping temperature, and the filament coil spacing is adjusted or controlled by adjusting the temperature control point within the range of 1400 to 1800°C.

[0021] Preferably, the temperature of the two leads of the filament is 950±100℃ when heated by a natural gas or hydrogen burner.

[0022] Preferably, after chemical cleaning, the bent area of ​​the two leads is inspected under a microscope to remove hidden damage and wire splitting defects. At room temperature, the cold assembly is measured with a milliohm meter holding the two leads of the filament to ensure it meets the requirements.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. The X-ray tube filament winding molding structure of the present invention is simple, has low manufacturing cost, is easy to use, has a wide range of applications, high reusability, and low operating cost:

[0025] 1) The material for the X-ray tube filament winding mold is a conventional molybdenum (Mo1) rod. It has a simple structure and is formed by ordinary turning and milling metal cutting processes. The positioning pin and the die are designed separately, which makes it easy to replace the positioning pin if it is damaged.

[0026] 2) X-ray tube filament winding molds are suitable for various filament materials, with rectangular or circular cross-sections, and the materials can be coarse or fine.

[0027] 3) When making X-ray tube filaments using a filament winding mold, the spacing between the filament coils can be adjusted or controlled by adjusting the temperature control point during the shaping process.

[0028] 4) The X-ray tube filament winding mold can be reused indefinitely if the positioning pin is intact, and has a long service life.

[0029] 2. The present invention provides an X-ray tube filament winding mold, which can be used to regularly wind a coil-shaped X-ray tube filament that is different from a long, spiral filament. The filament is disc-shaped with a small and regular emitting surface, and the emitted electrons are relatively concentrated in space, making it easy to focus and improving the spatial resolution of image reconstruction. Attached Figure Description

[0030] Figure 1 A schematic diagram of the filament winding mold structure of the present invention.

[0031] Figure 2 A schematic diagram of the first main mold structure of the present invention.

[0032] Figure 3 A schematic diagram of the structure of the first main mold mounting pin and positioning pin of the present invention.

[0033] Figure 4 A schematic diagram of the second main mold structure of the present invention.

[0034] Figure 5 A schematic diagram of the clamping plate structure of the present invention.

[0035] Figure 6 A schematic diagram of the filament structure after winding and forming according to the present invention.

[0036] In the diagram: 1. First main mold, 2. Second main mold, 3. Clamping plate, 4. Positioning pin, 5. Insert pin. Detailed Implementation

[0037] The present invention will be further explained and described below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0038] Example 1

[0039] like Figure 1 As shown, an X-ray tube filament winding mold includes a first main mold 1, a second main mold 2, and a clamping plate 3. Both the first and second main molds are cylindrical. Among the two cylindrical main molds, the diameter of the first main mold 1 is larger than the diameter of the second main mold 2. The front end of the first main mold and the rear end of the second main mold are each provided with two positioning holes. Two positioning pins 4 are provided in the two positioning holes of the first main mold 1. Angular grooves are formed on both sides of the first main mold 1 along the front end of the first main mold 1, and the two angular grooves are symmetrically arranged in opposite directions. The rear part of the two angular grooves is provided with a pin hole that penetrates the first main mold 1 for inserting a pin 5. The first and second main molds are disassembled and connected by inserting positioning pins into the positioning holes. After the first and second main molds are joined, their exterior is fixed by the clamping plate 3. The clamping plate 3 consists of two semi-circular grooves. The front half of the semi-circular groove matches the outer diameter of the second main mold, and the rear half matches the outer diameter of the first main mold. After the clamping plate 3 is fixed, the pin hole of the first main mold 1 is located behind the clamping plate, and the pin 5 is inserted. The first main mold 1, the second main mold 2, and the clamping plate 3 are all made of high-melting-point, low-expansion-coefficient molybdenum (Mo1) material and formed by conventional metal cutting processes.

[0040] The specific implementation steps are as follows: The incense-shaped filament material is pure tungsten strip with a cross-section of 0.3×0.3mm. 2 filament disc diameter Number of turns: 5; Turn spacing: (0.3±0.1) mm; Pin length: (10±0.5) mm; Pin spacing: (5.6±0.5) mm; Room temperature cooling resistance: (45±3) mΩ. Figure 6As shown.

[0041] The diameter of the filament winding die is designed to be [missing information]. The pin is 15mm from the disk surface, the locating pin spacing is 1.0mm, the locating pin diameter is 0.5mm, and the material is a molybdenum M01 rod. The structure is as follows: Figures 1-5 As shown, process according to the drawing, inspect and pass the test, chemically clean, and then insert two positioning pins into the two positioning holes at the front end of the first main mold 1 and rivet them in place. Use the processed filament winding mold to wind the above-mentioned incense coil-shaped filament, as detailed below:

[0042] S1. Clamp the tail ends of main mold 1 and main mold 2 on the chuck and tailstock of the horizontal lathe respectively, and insert a pin on the first main mold 1; hook the tungsten strip to be wound onto one of the two positioning pins of the first main mold 1, and pull the two ends of the tungsten strip together and tighten it.

[0043] S2. Move the lathe tailstock closer to the first main mold 1 on the chuck, slightly rotate the tailstock to engage the locating pin with the main mold 2, clamp the tungsten strip between the first main mold 1 and the second main mold 2, and try to rotate the tungsten strip so that it can move radially along the mold without being clamped, and fix the lathe tailstock.

[0044] S3. Ignite the natural gas flame and heat the contact point between the mold and the tungsten strip until the tungsten strip turns red. Maintain the temperature at 950±100℃. Pull the two ends of the tungsten strip together and tighten it to maintain tension. Slowly rotate the lathe chuck counterclockwise and feed the filament synchronously with the rotation of the first main mold 1. Wrap the filament material around the gap between the first and second main molds until the mold plate is filled.

[0045] S4. Using the natural gas torch, bend the tungsten strip on the inner ring and hook it onto the groove of the first main mold 1. Wrap the end of the tungsten strip around the pin and cut off the excess. Use the same method to bend and hook the other end of the tungsten strip, wrap it around and cut it off, then extinguish the torch.

[0046] S5. Clamp the first main mold 1 and the second main mold 2 with clamps, tie the buckle plate with tungsten wire, remove the mold and place it in the hydrogen furnace to pass wet hydrogen for 15 minutes, test the hydrogen purity, ignite and heat up, maintain at (1600±10)℃ for 20 minutes and then cool down to below 60℃ in the furnace, remove the mold and remove the filament; use flat-nose pliers along with the natural gas burner to bend and shape the two leads of the filament according to the drawing requirements, and then chemically clean the filament;

[0047] S6. The diameter of the filament disc measured by a metrological microscope is 6.15 mm, the coil spacing is 0.3-0.35 mm, the number of coils is 5, the lead length is 10.2 mm, and the distance between the two leads is 5.6 mm. Microscopic inspection of the disc surface and the bent parts of the leads shows no hidden damage or cracks. At room temperature, the cold resistance of the filament is measured by connecting the two leads to a micro-ohmmeter and is 46.3 mΩ, which meets the technical requirements.

[0048] Example 2

[0049] This embodiment is basically the same as Embodiment 1, except that: the filament material of the coil-shaped lamp in this embodiment is a tungsten-rhenium alloy wire with a cross-sectional diameter of 0.5 mm and a coil diameter of... Number of turns 4.5±0.5, turn spacing (0.5±0.1)mm, two-pin length (15±0.5)mm, pin spacing (9.5±0.5)mm, room temperature cooling group (63±5)mΩ.

[0050] The diameter of the filament winding die is designed to be The distance between the pin and the disc surface is 15mm, the spacing between the positioning pins is 1.5mm, and the diameter of the positioning pin is 0.6mm.

[0051] The filament setting temperature was (1700±10)℃ and maintained for 20 minutes.

[0052] The finished product, measured with a metrological microscope, has a filament disc diameter of 12.3 mm, a coil spacing of 0.5–0.55 mm, 5 coils, a lead length of 15.2 mm, and a lead spacing of 9.8 mm. The filament cold resistance, measured with a micro-ohmmeter, is 62.5 mΩ, which meets the technical requirements.

Claims

1. A method for manufacturing filaments using a filament winding mold for X-ray tubes, characterized in that: The X-ray tube filament winding mold includes a first main mold (1), a second main mold (2), and a clamping plate (3); both the first and second main molds are cylindrical; the front end of the first main mold (1) and the rear end of the second main mold (2) are each provided with two positioning holes; angular grooves are opened on both sides of the first main mold (1) along the front end of the first main mold (1), and the two angular grooves are symmetrically arranged in opposite directions; the rear part of the two angular grooves is provided with a pin hole that penetrates the first main mold (1), and the pin hole is used to install a pin (5); positioning pins (4) are respectively provided in the two positioning holes at the front end of the first main mold (1), and the front end of the first main mold (1) and the rear end of the second main mold (2) are connected by positioning pins (4). 4) Connection; The first main mold (1) and the second main mold (2) are fixed together by a clamping plate (3); The clamping plate (3) is a semi-circular groove plate, the front half of which matches the outer diameter of the second main mold and the rear half of which matches the outer diameter of the first main mold; The first main mold (1), the second main mold (2), and the clamping plate (3) are made of high-melting-point, low-expansion-coefficient molybdenum (Mo1) metal, and are manufactured by metal cutting process; The geometric dimensions of the filament winding mold vary with the thickness of the filament material, the diameter of the disk surface, and the spacing between the coils; The X-ray tube filament winding mold is used in winding filament materials with rectangular or circular cross-sections, and its filament manufacturing method specifically includes the following steps: S1. The rear end of the first main mold and the front end of the second main mold are respectively clamped in the chuck and tailstock of the horizontal lathe; one of the positioning pins at the front end of the first main mold hooks the filament material, and pulls the two ends of the filament material together to maintain a certain tension; S2. Move the lathe tailstock to bring the second main mold closer to the first main mold, slightly rotate the tailstock to match the positioning hole of the second main mold with the positioning pin on the first main mold, clamp the filament material between the first and second main molds, and try to rotate the filament material so that it can move radially along the mold without being clamped, and then fix the lathe tailstock. S3. Ignite the natural gas or hydrogen burner and heat the contact area between the mold and the filament material until the filament material turns red-hot, with the temperature at 950±100℃. Then, slowly rotate the lathe chuck counterclockwise so that the entire winding mold rotates with the lathe chuck, tightening the filament material and feeding it synchronously, so that the filament material is tightly wound around the gap between the first and second main molds until the mold plate is filled. S4. Separate the two leads of the filament material, tighten the hooks and hang them on the groove teeth on both sides of the first main mold, then wrap the filament material around the pin at the tail of the first main mold, and cut off the remaining material; S5. Attach the clamping plate to the first and second main molds and bind it with tungsten wire. Remove the bound mold from the lathe and place it in the hydrogen furnace to purge with humid hydrogen. Select a temperature control point in the temperature range of 1400-1800℃ and control the temperature difference within ±10℃. Maintain this temperature for 20 minutes to shape the filament. Cool the temperature down to below 60℃, remove the mold and filament. Heat the filament with a natural gas or hydrogen torch and shape the two leads of the filament with flat-nose pliers. Chemically clean the filament.

2. The method for manufacturing an X-ray tube filament using a filament winding mold as described in claim 1, characterized in that: The filament material is any one of tungsten or tungsten alloy wire, molybdenum or molybdenum alloy wire, and the cross-section of the filament material is rectangular or circular, with a cross-sectional area between 0.015 and 0.785 mm².

3. The method for manufacturing an X-ray tube filament using a filament winding mold as described in claim 2, characterized in that: The filament coil spacing is related to the setting temperature, and the filament coil spacing can be adjusted or controlled by adjusting the temperature control point within the range of 1400 to 1800℃.

4. The method for manufacturing a filament using a filament winding mold for X-ray tubes as described in claim 3, characterized in that: The temperature of the two leads of the filament is 950±100℃ when heated by a natural gas or hydrogen burner.

5. A method for manufacturing an X-ray tube filament using a filament winding mold as described in claim 2, 3, or 4, characterized in that: After chemical cleaning, the bent areas of the two leads were inspected under a microscope to remove any hidden damage and wire splitting defects. The cold assembly was measured at room temperature using a milliohm meter while holding the two leads of the filament and met the requirements.

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