A processing method for industrial CT scattered ray correction plate

Abstract

The present invention relates to a method for processing scattered radiation correction plates for industrial CT scans, belonging to the field of materials processing technology. The method comprises the following steps: 1) copper alloy blanking; 2) pre-machining treatment; 3) machining treatment; 4) post-machining treatment; 5) magnetron sputtering pre-treatment; 6) magnetron sputtering treatment; and 7) polishing and fine-tuning. The magnetron sputtering treatment effectively improves the corrosion resistance of the radiation correction plates and increases their roughness, thereby reducing costs and improving accuracy.

Description

Technical Field

[0001] The invention relates to a method for processing an industrial CT scattered ray correction plate, and belongs to the technical field of material processing. Background Art

[0002] Non-destructive imaging detection technology has a wide range of applications in medical imaging diagnosis and treatment, life sciences, materials science, industrial applications, and security inspections, among which X-ray imaging is one of the most important methods.

[0003] Generally speaking, X-ray imaging contains a large amount of scattered radiation, which significantly reduces the accuracy of the CT values ​​obtained during the scattered radiation imaging process. Therefore, a scattered radiation correction plate, also known as a grating, is required. This device can significantly improve the accuracy of CT values ​​obtained from scattered radiation imaging, but the type and surface condition of the scattered radiation correction plate have a crucial impact on CT value accuracy.

[0004] Currently, scattered radiation correction plates are generally made of metal tungsten alloy, copper alloy, etc., and have the following main problems:

[0005] 1) Tungsten alloy is not only expensive but also difficult to machine, especially for processing micro-holes of 1-2 mm, which results in a high overall cost of the correction plate;

[0006] 2) The price of copper alloy materials is relatively low, but copper alloy has poor corrosion resistance under continuous radiation, which leads to a significant reduction in the surface roughness of the micropores, affecting the test results. At present, in order to save costs, copper alloy materials are first selected to replace tungsten alloy materials. Secondly, the selection of copper alloy materials can also greatly save the cost of processing holes; however, the corrosion resistance of copper alloy is poorer than that of tungsten alloy, so copper alloy needs to be surface treated. The current existing copper alloy surface treatment process cannot meet the requirements of uniform coating for micropores of 1 to 2 mm, cannot obtain low roughness, and cannot obtain a step coating to increase its bonding strength and thus improve corrosion resistance.

[0007] Therefore, it is urgent to design a processing method for industrial CT scattered ray correction plate that can solve the above technical problems. Summary of the Invention

[0008] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a processing method for a copper alloy radiation correction plate. The magnetron sputtering process can effectively improve the corrosion resistance of the radiation correction plate without increasing the roughness, thereby reducing costs and improving accuracy.

[0009] The method for processing an industrial CT scattered-ray correction plate of the present invention is characterized in that it comprises the following steps:

[0010] 1) Copper alloy blanking

[0011] According to the size of the scattered-ray correction plate used in the CT equipment, the copper plate is cut by wire cutting;

[0012] 2) Pre-processing process

[0013] After cutting, the components are ultrasonically rinsed to remove surface oil and debris;

[0014] Preferably, the ultrasonic cleaning solution is 0.1-0.5 g / L NaOH solution, and the cleaning time is 10-70 min;

[0015] 3) Machining

[0016] Micropores are opened according to the size of the component and the equipment requirements, and the surface roughness of the component after opening is processed to below 16 microns;

[0017] Preferably, the micro-holes are trapezoidal, and the micro-holes are processed by a six-axis CNC drilling machine. After the processing is completed, the scattered ray correction plate is processed as a whole by a CNC lathe. After the processing is completed, the surface roughness is ensured to be below 16 microns;

[0018] 4) Machining post-processing

[0019] The component processed in step 3) is subjected to ultrasonic water washing to remove surface oil and debris, and then chemical degreasing and deionized water washing are carried out in sequence, and then dried at room temperature;

[0020] Preferably, the ultrasonic washing time is 10 to 70 minutes;

[0021] Preferably, the chemical degreasing is performed by washing with a NaOH solution, the concentration of the NaOH solution is 0.1 to 5 g / L, and the washing time is 10 to 20 seconds;

[0022] Preferably, during the deionized water washing, the water temperature is 15-30°C and the rinsing time is 10-20 minutes;

[0023] 5) Magnetron sputtering pre-treatment process

[0024] First, the components treated in step 4) need to be ultrasonically rinsed with acetone and alcohol for 3 to 10 minutes, and then dried. Then, a high-purity tungsten target is used to bombard the components in a magnetron sputtering device for 5 to 20 minutes. The initial negative bias voltage of the magnetron sputtering device is controlled to be 800-1000V and the chamber pressure is (5 to 7)×10 -4 Pa, temperature is 400~600℃;

[0025] Preferably, the drying is performed by wrapping the wire around the edge of the component at least once and hanging it to dry;

[0026] Preferably, the tungsten content in the high-purity tungsten target is not less than 99.98%;

[0027] 5) Magnetron sputtering process

[0028] A high-purity Ta10W target is used in a hollow cathode assisted multi-arc ion plating composite deposition device to deposit a Wu film layer for 10 to 30 minutes; vacuum is continued to deposit a Ta10W film layer for 5 to 15 minutes; after the Wu / Ta-10W coating is repeated 2 to 3 times, a Wu film layer is deposited for 60 to 180 minutes to form a multi-layer structure. After the various coatings on the component diffuse and fuse with each other, the component is adjusted to room temperature and cooled, and the component is rinsed with deionized water before proceeding to the next process;

[0029] Preferably, when depositing the Wu film layer in the hollow cathode assisted multi-arc ion plating composite deposition device, the current of the hollow cathode assisted multi-arc ion plating composite deposition device is adjusted to 80-150A, the initial negative bias voltage is 800-1000V, and the chamber pressure is (5-7)×10 -4 Pa, the temperature is 400-600 ° C, the reaction gas Ar is filled in at a flow rate of 0.05-0.35 L / min;

[0030] Preferably, after forming a multi-layer structure, the temperature is adjusted to 200-400° C. and the holding time is 180-300 minutes, so that the coatings of the component diffuse and fuse with each other;

[0031] Preferably, in the high-purity Ta10W target, the target material purity is not less than 99.95%, the Ta content is 90%, and the Wu content is 10%;

[0032] 6) Polishing fine-tuning

[0033] The component obtained in step 5) is polished using a polishing machine and a polishing cloth, then cleaned and dried at room temperature to obtain an industrial CT scattered ray correction plate.

[0034] Preferably, the polishing is first performed using a mechanical polishing machine at a rotation speed of 1000 to 2000 r / min, after spraying the polishing liquid, polishing is performed for 30 to 60 seconds, and then fine-tuning is performed using a polishing cloth.

[0035] Compared with the prior art, the advantages of the present invention are:

[0036] 1) The use of copper alloy scattered light correction plate greatly reduces the cost;

[0037] 2) Copper alloy is much easier to process than other materials such as tungsten alloy, and the processing cost is also reduced;

[0038] 3) The magnetron sputtering method of the present invention not only solves the problem of microporous coating, but also improves the bonding strength of the obtained step film layer and greatly enhances the corrosion resistance of the copper alloy. At the same time, the magnetron sputtering method of the present invention does not increase the roughness of the micropores during machining, thereby extending the service life of the copper alloy and improving the accuracy of the CT value results.

[0039] 4) The patented method of this invention achieves the same effect as tungsten alloy measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The figure is a schematic diagram of the structure of a typical copper alloy scattered light correction plate with trapezoidal microholes, wherein the microholes are trapezoidal in shape.

[0041] Figure 2 This is a process flow chart of the method for processing an industrial CT scattered ray correction plate according to the present invention;

[0042] Figure 3 Diagram showing the wire hanging through the hole and the wire hanging around the board;

[0043] Figure 4 A diagram showing the magnitude of the charge density when the wire is suspended through a hole and when the wire is suspended around a plate. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0045] Example 1

[0046] A method for processing an industrial CT scattered-ray correction plate according to this embodiment includes the following steps, as described in 1-4:

[0047] 1) Copper alloy cutting: Wire cutting is used to cut the copper plate according to the size of the scattered beam correction plate used in the CT equipment.

[0048] 2) Pre-machining treatment: After cutting, ultrasonic washing is performed to remove surface oil and debris. The ultrasonic washing fluid used is 0.1g / L NaOH solution, and the washing time is 10 minutes.

[0049] 3) Machining: Design the size and quantity of micro-holes according to the size of the component and the equipment requirements (attached Figure 1As shown), a 6-axis CNC drilling machine is used to process the trapezoidal micro-holes. After the processing is completed, a CNC lathe is used to process the entire scattered ray correction plate. After the processing is completed, the surface roughness is guaranteed to be below 16 microns.

[0050] 4) Post-machining treatment: The finished scattered light correction plate is ultrasonically washed for 10 minutes to remove surface oil and debris; further chemical degreasing is performed by rinsing with NaOH solution, the concentration of NaOH solution is 0.1g / L, and the washing time is 10s; then the component is washed with deionized water at a water temperature of 15°C and a rinsing time of 10 minutes; since the roughness of the machined surface is very low and there is no oxide layer on the surface, pickling is not required, and after cleaning, it is blown dry at room temperature and cannot be dried in an oven.

[0051] 5) Magnetron sputtering pre-treatment process: customized high-purity tungsten target (tungsten content not less than 99.98%), high-purity Ta10W target (target material purity not less than 99.95%, Ta content 90%, Wu content 10%); using hollow cathode assisted multi-arc ion plating composite deposition equipment, the copper alloy radiation correction plate must first be ultrasonically rinsed with acetone and alcohol for 3 minutes before magnetron sputtering treatment, and then dried after completion; according to the commonly used workpiece connection method, it is generally carried out by hanging the wire through the hole, but this will cause traces or ablation, and according to the results of a large number of numerical simulation analyses, it is also found that there is charge concentration at the hole, which seriously affects the film formation effect, such as the attached Figure 3 Middle a, attached Figure 4 As shown in Figure c, the wires should be connected at the edge and wrapped around the board. Figure 3 Middle b, attached Figure 4 As shown in (d), the charge density is reduced by an order of magnitude.

[0052] Magnetron sputtering component connection wire method: The wire should be connected at the edge and wrapped around the board. Figure 3 As shown in b.

[0053] Before deposition, the tungsten target was bombarded for 5 min, the initial negative bias voltage was 800 V, and the chamber pressure was 5×10 -4 Pa, temperature is 400℃.

[0054] 6) Magnetron sputtering process: the current is adjusted to 80A, the initial negative bias voltage is 800V, and the chamber pressure is 5×10 -4Pa, the temperature is 400℃, the reaction gas Ar is filled in with a flow rate of 0.05L / min, and the Wu film layer is deposited for 10 minutes; continue to evacuate and deposit the Ta10W film layer for 5 minutes; after the Wu / Ta-10W coating is repeated twice, the Wu film layer is deposited for 60 minutes to form a multi-layer structure, the temperature is adjusted to 200℃, and the holding time is 180 minutes. After the various coatings of the component diffuse and fuse with each other, the component is adjusted to room temperature and cooled, stopped, and the component is removed and rinsed with deionized water before proceeding to the next process.

[0055] 7) Polishing fine-tuning: Polish with a mechanical polishing machine and polishing cloth at a speed of 1000r / min. After spraying the polishing liquid, polish for 30s, then clean and dry at room temperature.

[0056] Example 2

[0057] A method for processing an industrial CT scattered-ray correction plate according to this embodiment includes the following steps:

[0058] 1) Copper alloy cutting: According to the size of the scattered beam correction plate used in the CT equipment, the copper plate is cut by wire cutting. The main purpose of wire cutting is to reduce the processing stress of the component.

[0059] 2) Pre-machining treatment: After cutting, ultrasonic washing is performed to remove surface oil and debris. The ultrasonic washing fluid used is 0.3g / L NaOH solution, and the washing time is 35 minutes.

[0060] 3) Machining: Machining the same dimensions as in Comparative Example 1, ensuring that the surface roughness is below 16 μm after machining.

[0061] 4) Post-machining treatment: The finished scattered light correction plate is ultrasonically washed for 35 minutes to remove surface oil and debris; further chemical degreasing is performed by rinsing with NaOH solution at a concentration of 3g / L for 15 seconds; then the component is washed with deionized water at a water temperature of 25°C for 15 minutes; since the roughness of the machined surface is very low and there is no oxide layer on the surface, pickling is not required, and after cleaning, it is blown dry at room temperature and cannot be dried in an oven.

[0062] 5) Magnetron sputtering pre-treatment process: customized high-purity tungsten target (tungsten content not less than 99.98%), high-purity Ta10W target (target purity not less than 99.95%, Ta content 90%, Wu content 10%); the magnetron sputtering in the present invention adopts hollow cathode assisted multi-arc ion plating composite deposition equipment, and the copper alloy radiation correction plate needs to be ultrasonically rinsed with acetone and alcohol for 6 minutes before magnetron sputtering treatment, and then dried after completion; the way to connect the wires of the magnetron sputtering components: the wires should be connected at the edge and wrapped around the plate, as shown in the attached figure. Figure 3 As shown in b.

[0063] Before deposition, the tungsten target was bombarded for 15 min, the initial negative bias voltage was 900 V, and the chamber pressure was 6×10 -4 Pa, temperature is 500℃.

[0064] 6) Magnetron sputtering process: the current is adjusted to 120A, the initial negative bias voltage is 900V, and the chamber pressure is 6×10 - 4 Pa, the temperature is 500℃, the reaction gas Ar is filled in with a flow rate of 0.2L / min, and the Wu film layer is deposited for 20 minutes; continue to evacuate and deposit the Ta10W film layer for 10 minutes; after the Wu / Ta10W coating is repeated twice, the Wu film layer is deposited for 120 minutes to form a multi-layer structure, the temperature is adjusted to 300℃, and the holding time is 240 minutes. After the various coatings of the component diffuse and fuse with each other, the component is adjusted to room temperature and cooled, stopped, and the component is removed and rinsed with deionized water before proceeding to the next process.

[0065] 7) Polishing fine-tuning: Polishing is done using a mechanical polishing machine and polishing cloth at a speed of 1500 r / min. After spraying the polishing liquid, polish for 45 seconds, then clean and dry at room temperature.

[0066] Example 3

[0067] A method for processing an industrial CT scattered-ray correction plate according to this embodiment includes the following steps:

[0068] 1) Copper alloy cutting: According to the size of the scattered beam correction plate used in the CT equipment, the copper plate is cut by wire cutting. The main purpose of wire cutting is to reduce the processing stress of the component.

[0069] 2) Pre-machining treatment: After cutting, ultrasonic washing is performed to remove surface oil and debris. The ultrasonic washing fluid used is 0.5g / L NaOH solution, and the washing time is 70 minutes.

[0070] 3) Machining: Machining the same dimensions as in Comparative Example 1, ensuring that the surface roughness is below 16 μm after machining.

[0071] 4) Post-machining treatment: The processed scattered light correction plate is ultrasonically washed for 70 minutes to remove surface oil and debris; further chemical degreasing is performed by rinsing with NaOH solution with a concentration of 5g / L and a washing time of 20s; then the component is washed with deionized water at a water temperature of 30°C and a rinsing time of 20min; since the roughness of the machined surface is very low and there is no oxide layer on the surface, pickling is not required, and after cleaning, it is blown dry at room temperature and cannot be dried in an oven.

[0072] 5) Magnetron sputtering pre-treatment process: customized high-purity tungsten target (tungsten content not less than 99.98%), high-purity Ta10W target (target material purity not less than 99.95%, Ta content 90%, Wu content 10%); the magnetron sputtering in the present invention adopts hollow cathode assisted multi-arc ion plating composite deposition equipment, and the copper alloy radiation correction plate needs to be ultrasonically rinsed with acetone and alcohol for 10 minutes before magnetron sputtering treatment, and then dried after completion; the way to connect the wires of the magnetron sputtering components: the wires should be connected at the edge and wrapped around the plate, as shown in the attached figure. Figure 3 As shown in b.

[0073] Before deposition, the tungsten target was bombarded for 20 min, the initial negative bias voltage was 1000 V, and the chamber pressure was 7×10 -4 Pa, temperature is 600℃.

[0074] 6) Magnetron sputtering process: the current is adjusted to 150A, the initial negative bias voltage is 1000V, and the chamber pressure is 7×10 - 4 Pa, the temperature is 600℃, the reaction gas Ar is filled in at a flow rate of 0.35L / min, and the Wu film layer is deposited for 30 minutes; continue to evacuate and deposit the Ta10W film layer for 15 minutes; after the Wu / Ta10W coating is repeated three times, the Wu film layer is deposited for 180 minutes to form a multi-layer structure, the temperature is adjusted to 400℃, and the holding time is 300 minutes. After the various coatings of the component diffuse and fuse with each other, the component is adjusted to room temperature and cooled, stopped, and the component is removed and rinsed with deionized water before proceeding to the next process.

[0075] 7) Polishing fine-tuning: Polishing is done using a mechanical polishing machine and polishing cloth at a speed of 2000r / min. After spraying the polishing liquid, polish for 60s, then clean and dry at room temperature.

[0076] Comparative Example 4

[0077] Tungsten alloy scattered radiation correction plate after tungsten alloy machining.

[0078] Comparative Example 5

[0079] A copper alloy scattered radiation correction plate that has not been processed after copper alloy processing is used.

[0080] Using the scattered radiation correction plates obtained in Comparative Examples 1-5, CT measurements were performed on an aircraft engine blade, using the tungsten alloy image as a benchmark. Table 1 shows the results. It can be seen that the results of Comparative Examples 1-3, treated with the present invention, are not much different from those of the tungsten alloy in Comparative Example 4, but are significantly higher than those of the untreated copper alloy in Comparative Example 5. These results demonstrate that the present invention can achieve excellent results.

[0081] Table 1 CT results of different comparative examples

[0082] Example CT image results Comparative Example 1 Fewer artifacts Comparative Example 2 Fewer artifacts Comparative Example 3 Fewer artifacts Comparative Example 4 Baseline, fewer artifacts Comparative Example 5 Many artifacts

Claims

1. A method for processing an industrial CT scattered ray correction plate, characterized in that The following steps are involved: 1) Copper alloy blanking According to the size of the scattered-ray correction plate used in the CT equipment, the copper plate is cut by wire cutting; 2) Machining pre-treatment process After cutting, the components are ultrasonically rinsed to remove surface oil and debris; 3) Machining Micropores are opened according to the size of the component and the equipment requirements, and the surface roughness of the component after opening is processed to below 16 microns; 4) Machining post-processing The component processed in step 3) is subjected to ultrasonic water washing to remove surface oil and debris, and then chemical degreasing and deionized water washing are carried out in sequence, and then dried at room temperature; 5) Magnetron sputtering pre-treatment process First, the components treated in step 4) need to be ultrasonically rinsed with acetone and alcohol for 3 to 10 minutes, and then dried. Then, a high-purity tungsten target is used to bombard the components in a magnetron sputtering device for 5 to 20 minutes. The initial negative bias voltage of the magnetron sputtering device is controlled to be 800-1000V and the chamber pressure is (5 to 7)×10 -4 Pa, temperature is 400~600℃; 6) Magnetron sputtering process A high-purity Ta10W target was used to deposit the Wu film layer in a hollow cathode assisted multi-arc ion plating composite deposition equipment for 10 to 30 minutes. Continue to evacuate the chamber and deposit the Ta10W film for 5-15 minutes. Repeat this process for 2-3 times for the Wu / Ta-10W coating. Deposit the Wu film for 60-180 minutes to form a multilayer structure. After the coatings on the component diffuse and fuse with each other, adjust the temperature to room temperature, cool the component, and rinse it with deionized water. 7) Polishing fine-tuning Polishing the component obtained in step 6) using a polishing machine and a polishing cloth, then cleaning it and drying it at room temperature to obtain an industrial CT scattered ray correction plate; Step 3) The micropores are trapezoidal, and the micropores are machined using a six-axis CNC drilling machine. After the machining is completed, the scattered radiation correction plate is machined as a whole using a CNC lathe. After the machining is completed, the surface roughness is ensured to be below 16 microns; Step 6) When depositing the Wu film layer in the hollow cathode assisted multi-arc ion plating composite deposition device, the current of the hollow cathode assisted multi-arc ion plating composite deposition device is adjusted to 80-150A, the initial negative bias voltage is 800-1000V, and the chamber pressure is (5-7)×10 -4 Pa, the temperature is 400-600 ° C, and the reaction gas Ar is charged at a flow rate of 0.05-0.35 L / min; After forming a multi-layer structure, the temperature is adjusted to 200-400° C. and the heat preservation time is 180-300 minutes to allow the coatings of the component to diffuse and fuse with each other.

2. The method for processing an industrial CT scattered-ray correction plate according to claim 1, characterized in that In step 2), the ultrasonic cleaning is carried out using a 0.1-0.5 g / L NaOH solution as the rinsing solution, and the cleaning time is 10-70 min.

3. The method for processing an industrial CT scattered-ray correction plate according to claim 1, characterized in that Step 4) The ultrasonic washing time is 10 to 70 minutes.

4. A method for processing an industrial CT scattered-ray correction plate according to claim 3, characterized in that Step 4) The chemical degreasing is performed by washing with a NaOH solution, the concentration of the NaOH solution is 0.1 to 5 g / L, and the washing time is 10 to 20 seconds.

5. A method for processing an industrial CT scattered-ray correction plate according to claim 3 or 4, characterized in that In step 4), the deionized water washing is performed at a water temperature of 15 to 30° C. and a rinsing time of 10 to 20 minutes.

6. The method for processing an industrial CT scattered-ray correction plate according to claim 1, characterized in that Step 5) drying is to wrap the wire around the edge of the component at least once and hang it to dry; The tungsten content in the high-purity tungsten target is not less than 99.98%.

7. The method for processing an industrial CT scattered-ray correction plate according to claim 1, characterized in that In step 6), the high-purity Ta10W target has a target material purity of not less than 99.95%, a Ta content of 90%, and a Wu content of 10%.

8. The method for processing an industrial CT scattered-ray correction plate according to claim 1, characterized in that Step 7) The polishing is first performed using a mechanical polishing machine at a rotation speed of 1000-2000 r / min. After spraying the polishing liquid, polishing is performed for 30-60 seconds, and then fine-tuning is performed using a polishing cloth.

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