Preparation method of super-precision platinum-iridium C type ring for developing

Abstract

This application relates to the field of metal material processing technology, specifically to a method for preparing ultra-precision platinum-iridium C-rings for developing. The method of this invention first prepares a tube blank, then uses a laser to segmentally cut the surface of the platinum-iridium alloy tube to form grooves. After cutting, the entire tube is heat-treated at a low temperature, and then the C-ring is cut. Finally, plasma polishing is used to remove surface impurities and burrs to obtain the finished C-ring. This invention overcomes the limitations of existing technologies that require specialized equipment for C-ring preparation, avoids the opening of the C-shaped ends due to stress release after heat treatment, and solves problems such as difficulty in removing burrs after cutting and low production efficiency. It provides a simple, efficient, and suitable-for-large-scale mass production technology for preparing ultra-precision platinum-iridium C-rings for developing, resulting in excellent surface quality and precise dimensions.

Description

Technical Field

[0001] This invention relates to the field of metal material processing technology, and specifically to a method for preparing an ultra-precision platinum-iridium C-ring for developing. Background Technology

[0002] In terms of the market, there is a huge demand for biomedical materials and high profit margins. Implantable biomedical materials are becoming a pillar industry of the world economy.

[0003] Platinum-iridium alloys possess excellent physical and chemical properties, such as good biocompatibility and corrosion resistance, which can reduce the risk of rejection and corrosion of implants in the human body; high strength and high ductility, which make them easy to process into various complex shapes; and the ability to effectively absorb and convert radiation energy such as X-rays, resulting in excellent imaging properties. Platinum-iridium alloys can meet the diverse needs of medical device design and are therefore widely used in implantable biomedical devices.

[0004] Platinum-iridium C-rings are in high demand annually and are widely used in the distal ends of interventional catheters for radiographic positioning. In complex surgical procedures, such as cardiovascular or neurosurgery, surgeons need to precisely locate and manipulate the catheter. Due to their high density and excellent radiation absorption, platinum-iridium C-rings are clearly visible under X-rays or other imaging equipment, helping surgeons to more accurately identify the catheter's location and thus perform delicate surgical procedures.

[0005] However, there are still some problems in the current processing of platinum-iridium C-rings: On the one hand, published patents, such as Chinese patent CN111112494A, require a fixed device to produce platinum-iridium C-rings, and the production size is limited. Therefore, different sizes of C-rings require corresponding devices, resulting in high costs. On the other hand, during the production of platinum-iridium C-rings, the C-rings are prone to the problem of the C-shaped ends opening, and the cut edges of the C-rings are prone to burrs that are difficult to remove, thus affecting subsequent use. Summary of the Invention

[0006] Therefore, in order to solve the problems in the prior art, the present invention proposes a method for preparing an ultra-precision platinum-iridium C-ring for development that does not rely on specific equipment, has a stable C-shaped port, and a smooth surface. The specific solution is as follows:

[0007] A method for preparing an ultra-precision platinum-iridium C-ring for development includes the following steps:

[0008] Step 1: After peeling and drilling the platinum-iridium alloy rod, a platinum-iridium tube blank is prepared. The air-dried platinum-iridium tube blank is then cold-rolled to 6mm or less through a mandrel in a rolling mill, followed by multiple cold drawing passes. The mandrel is then removed to obtain an ultra-fine platinum-iridium tube with an inner diameter of less than 0.61mm and a wall thickness of less than 0.05mm. Specifically, the mandrel and rolls of the rolling mill are both made of M42 high-speed steel or W... 18 Cr4V tungsten-based high-speed steel;

[0009] Step 2: Use two femtosecond or picosecond lasers to cut the ultra-fine platinum-iridium tube multiple times. The lasers cut along two straight lines parallel to the axial direction of the ultra-fine platinum-iridium tube. The angle between the endpoints of the two straight lines on the same longitudinal section and the center of the longitudinal section is greater than 10°. The length of each cut is 15-50cm. Then, cut at both ends of the two parallel cutting lines to obtain a platinum-iridium tube with multiple long grooves. The spacing between two adjacent grooves is the same.

[0010] Step 3: Under the protective atmosphere of inert gas, the platinum-iridium tubing from Step 2 is subjected to low-temperature annealing treatment at a temperature of 300-400℃ for 10-15 minutes to obtain the treated platinum-iridium tubing.

[0011] Step 4: Cut the platinum-iridium tubing from Step 3 to obtain a C-ring;

[0012] Step 5: Perform plasma cleaning on the C-ring from Step 4;

[0013] Step 6: Clamp the C-ring cleaned in Step 5 onto a special fixture, then immerse it in a polishing solution and apply direct current to perform plasma polishing. The polishing solution comprises 0.5%-4% sulfate and 0.1%-2% complexing agent by mass. The temperature of the polishing solution is controlled at 70-100℃. After polishing, dry to obtain a C-shaped platinum-iridium ring. Preferably, the solvent of the polishing solution is water, and the drying time in an oven is 5-30 minutes.

[0014] Furthermore, the ultra-fine platinum-iridium tubes obtained in step 1 have an inner diameter of 0.2-0.6 mm and a wall thickness of 0.01-0.04 mm.

[0015] Furthermore, in step 1, the cold rolling speed is 200 mm / min-300 mm / min, the mill feed speed is 2 mm-5 mm / pass, and the processing rate per rolling pass is 10-15%.

[0016] Furthermore, the distance between the groove created in step 2 and the end of the ultra-fine platinum-iridium tube, and between two adjacent grooves, is 2-5 cm.

[0017] Furthermore, in step 2, the angle between the endpoints of the two straight lines on the same longitudinal section and the center of the longitudinal section is 30°-120°.

[0018] Furthermore, the cutting method in step 4 is femtosecond laser or picosecond laser cutting, the cutting direction is perpendicular to the tube, and the distance between two cuts is less than 1mm.

[0019] Furthermore, the process conditions for plasma cleaning in step 5 are as follows: when the vacuum degree is less than 10... -2 After Pa, a 99.99% pure argon-hydrogen mixture is introduced at a flow rate of 5-15 SCCM. The vacuum level after introducing the argon-hydrogen mixture is 5-10 Pa, and the cleaning time is 400-600 s.

[0020] Furthermore, the sulfate mentioned in step 6 is one or more of ammonium sulfate, sodium sulfate, and zinc sulfate.

[0021] Further, the complexing agent mentioned in step 6 is one or a mixture of ethylenediaminetetraacetic acid tetrasodium, citric acid, and succinic acid.

[0022] Furthermore, the DC voltage mentioned in step 6 is 260-300V, and the current density is 60-90A / dm². 2 .

[0023] The beneficial effects of this invention are as follows:

[0024] (1) This invention uses femtosecond or picosecond lasers to cut C-shaped openings on the surface of platinum-iridium tubing, avoiding the problem of needing a specific device to make C-rings. In addition, the precise cutting of C-rings of different specifications and sizes can be achieved simply by adjusting the relative positions of the two laser beams. This method is simple, feasible and flexible to different industrial needs.

[0025] (2) The present invention performs low-temperature annealing on a single platinum-iridium tube with a 15-50cm long groove every 2-5cm, and then cuts it: On the one hand, heat-treating the entire platinum-iridium tube before cutting can avoid the deformation problem of the C-shaped port opening due to stress release after heat treatment in the process of cutting first and then heat treatment. On the other hand, annealing at low temperature can eliminate the stress generated during processing and ensure the strength of the C-shaped platinum-iridium ring, thus ensuring the performance of the product.

[0026] (3) The present invention uses femtosecond cutting, which can avoid the problems of thermal damage, deformation and burrs commonly found in traditional laser cutting. The cut ends are flush and the dimensional accuracy is high.

[0027] (4) This invention activates the surface of the platinum-iridium C-ring by plasma cleaning after filling it with argon-hydrogen mixture, increases surface wettability and improves adhesion, thereby greatly improving surface properties and facilitating subsequent processing applications. At the same time, the plasma cleaning process does not use chemical reagents, so it will not cause secondary pollution. The cleaning equipment is highly repeatable, requires relatively low equipment and operating costs, and is flexible and simple to operate. It can achieve the cleaning of the entire metal surface or certain local and complex structures.

[0028] (5) The present invention can effectively remove burrs and surface oxides generated after C-ring cutting by performing plasma polishing in a sulfate polishing solution. The finished product has no texture, smooth and uniform transition at the surface edges, and high yield. It can produce high-quality ultra-precision C-rings. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0030] Example 1:

[0031] This embodiment provides a method for preparing an ultra-precision platinum-iridium C-ring for developing, specifically including the following steps:

[0032] (1) After peeling the platinum-iridium alloy bar with an inner diameter of 20mm, drill holes to prepare a platinum-iridium tube blank. After air drying, insert the tube blank into the mandrel of the rolling mill. Use a rolling mill with a feed speed of 4mm / pass and a rolling speed of 200mm / min to roll the platinum-iridium tube blank to 6mm. Then, insert the platinum-iridium tube blank into the tube drawing die for multiple cold drawing, with a pass processing rate of 10%. Remove the mandrel to finally obtain an ultra-fine platinum-iridium tube with an inner diameter of 0.6mm and a wall thickness of 0.03mm.

[0033] (2) Two straight lines parallel to the axial direction of the tube are determined on the surface of the ultra-fine platinum-iridium tube. The angle between the endpoints of the two straight lines on the same longitudinal section and the center of the longitudinal section is 70°. Then, the platinum-iridium tube is cut along the two straight lines at a distance of 3cm from one end of the cut using a 1030nm picosecond laser. The cutting length is 16cm. Then, the two ends of the two parallel cutting lines are cut. After a 3cm interval, a groove of about 16cm is cut. The operation is repeated until the entire tube is cut. A platinum-iridium tube with a 16cm long groove every 3cm is obtained.

[0034] (3) The platinum-iridium tube with a 16cm groove is placed in an annealing furnace filled with argon gas for heat treatment at a temperature of 400℃ for 15 minutes.

[0035] (4) The heat-treated platinum-iridium tube was vertically cut using a 1030nm picosecond laser with a cutting distance of 0.2mm, resulting in a C-shaped ring with an inner diameter of 0.6mm, a wall thickness of 0.03mm, a length of 0.2±0.01mm, and a port angle of 70°.

[0036] (5) Place the C-shaped ring obtained in step 4 into the plasma cleaning chamber and evacuate the plasma cleaning chamber. When the vacuum degree is less than 10... -2 After Pa, argon-hydrogen mixture with a purity of 99.99% is introduced to a vacuum of 10 Pa and a flow rate of 15 SCCM. The mixture is then cleaned for 400 s to remove the impurities remaining on the surface of the C-type platinum-iridium ring obtained in step 4.

[0037] (6) The cleaned C-ring is placed on a hanger as an anode and immersed in a polishing solution prepared with a low concentration of neutral salt for polishing. The polishing solution contains 0.5% (mass fraction) ammonium sulfate, 0.5% (mass fraction) tetrasodium ethylenediaminetetraacetate (EDTA) complexing agent, water as solvent, at a temperature of 100°C, and is subjected to a voltage of 260V and a current density of 60A / dm³. 2 The C-ring is plasma polished using direct current, and then baked in a 50℃ oven for 30 minutes to obtain an ultra-precision platinum-iridium C-ring with a smooth, flat surface, free of burrs, cracks, and dents.

[0038] Example 2:

[0039] This embodiment provides a method for preparing an ultra-precision platinum-iridium C-ring for developing, specifically including the following steps:

[0040] (1) After peeling the platinum-iridium alloy bar with an inner diameter of 15mm, drill holes to prepare a platinum-iridium tube blank. After air drying, insert the tube blank into the mandrel of the rolling mill. Use a rolling mill with a feed speed of 5mm / pass and a rolling speed of 300mm / min to roll the platinum-iridium tube blank to 6mm. Then, insert the platinum-iridium tube blank into the tube drawing die for multiple cold drawing, with a pass processing rate of 15%. Remove the mandrel to finally obtain an ultra-fine platinum-iridium tube with an inner diameter of 0.2mm and a wall thickness of 0.03mm.

[0041] (2) Two straight lines parallel to the tube are determined on the surface of the ultra-fine platinum-iridium tube. The angle between the endpoints of the two straight lines on the same longitudinal section and the center of the longitudinal section is 100°. Then, the platinum-iridium tube is cut along the two straight lines at a distance of 2cm from one end. The cutting length is 22cm. Then, the two parallel cutting lines are cut at both ends. After a 2cm interval, a groove of about 22cm is cut. The operation is repeated until the entire tube is cut. A platinum-iridium tube with a 22cm long groove every 2cm is obtained.

[0042] (3) The platinum-iridium tube with a 22cm groove is placed in an annealing furnace filled with argon gas for heat treatment. The heat treatment time is 300℃ and the time is 10min.

[0043] (4) The heat-treated platinum-iridium tube was vertically cut using a 1030nm picosecond laser with a cutting distance of 0.2mm, resulting in a C-shaped ring with an inner diameter of 0.2mm, a wall thickness of 0.03mm, a length of 0.2±0.01mm, and a port angle of 100°.

[0044] (5) Place the C-shaped ring obtained in step 4 into the plasma cleaning chamber and evacuate the plasma cleaning chamber. When the vacuum degree is less than 10... -2 After Pa, an argon-hydrogen mixture with a purity of 99.99% is introduced to a vacuum of 5 Pa and a flow rate of 5 SCCM. The mixture is then cleaned for 600 s to remove the impurities remaining on the surface of the C-type platinum-iridium ring obtained in step 4.

[0045] (6) Place the cleaned C-ring on the hanger as the anode and immerse it in a polishing solution prepared with a low concentration of neutral salt for polishing. The polishing solution contains 4% sodium sulfate, 2% complexing agent citric acid, and water as the solvent. The temperature is 70°C, and the applied voltage is 300V with a current density of 90A / dm³. 2 The C-ring is plasma polished using direct current, and then baked in a 50℃ oven for 30 minutes to obtain an ultra-precision platinum-iridium C-ring with a smooth, flat surface, free of burrs, cracks, and dents.

[0046] Example 3:

[0047] This embodiment provides a method for preparing an ultra-precision platinum-iridium C-ring for developing, specifically including the following steps:

[0048] (1) After peeling the platinum-iridium alloy bar with an inner diameter of 30mm, drill holes to prepare a platinum-iridium tube blank. After air drying, insert the tube blank into the mandrel of the rolling mill. Use a rolling mill with a feed speed of 5mm / pass and a rolling speed of 300mm / min to roll the platinum-iridium tube blank to 6mm. Then, insert the platinum-iridium tube blank into the tube drawing die for multiple cold drawing, with a pass processing rate of 15%. Remove the mandrel to finally obtain an ultra-fine platinum-iridium tube with an inner diameter of 0.2mm and a wall thickness of 0.03mm.

[0049] (2) Two straight lines parallel to the tube are determined on the surface of the ultra-fine platinum-iridium tube. The angle between the endpoints of the two straight lines on the same longitudinal section and the center of the longitudinal section is 60°. Then, the platinum-iridium tube is cut along the two straight lines at a distance of 2cm from one end using a 1030nm picosecond laser. The cut length is about 15cm. Then, cut at both ends of the two parallel cutting lines. After a 2cm interval, cut a groove about 15cm long. Repeat the operation until the entire tube is cut, and a platinum-iridium tube with a 15cm long groove every 2cm is obtained.

[0050] (3) The platinum-iridium tube with a 15cm groove is placed in an annealing furnace filled with argon gas for heat treatment. The heat treatment time is 300℃ and the time is 10min.

[0051] (4) A 1030nm picosecond laser was used to cut the heat-treated platinum-iridium tube perpendicularly. The cutting distance was 0.2mm, and a C-shaped ring with an inner diameter of 0.2mm, a wall thickness of 0.03mm, a length of 0.2±0.01mm, and a port angle of 60° was finally obtained.

[0052] (5) Place the C-shaped ring obtained in step 4 into the plasma cleaning chamber and evacuate the plasma cleaning chamber. When the vacuum degree is less than 10... -2 After Pa, argon-hydrogen mixed gas with a purity of 99.99% is introduced to a vacuum of 8 Pa and a flow rate of 10 SCCM. The gas is then cleaned for 500 s to remove the impurities remaining on the surface of the C-type platinum-iridium ring obtained in step 4.

[0053] (6) Place the cleaned C-ring on the hanger as the anode and immerse it in a polishing solution prepared with a low concentration of neutral salt for polishing. The polishing solution contains 2% zinc sulfate, 1% complexing agent succinic acid, and water as the solvent. The temperature is 80℃, the voltage is 280V, and the current density is 70A / dm³. 2 The C-ring is plasma polished using direct current, and then baked in a 50℃ oven for 30 minutes to obtain an ultra-precision platinum-iridium C-ring with a smooth, flat surface, free of burrs, cracks, and dents.

[0054] The foregoing descriptions have outlined some exemplary embodiments of the present invention. It is understood that these embodiments are merely illustrative and do not constitute a limitation on the scope of protection of the present invention. Features in these embodiments can be rearranged in suitable ways, and the resulting solutions remain within the scope of protection claimed by the present invention. All other embodiments obtained by those skilled in the art based on the foregoing embodiments without inventive effort, i.e., all modifications, equivalent substitutions, and improvements made within the spirit and principles of this application, fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing an ultra-precision platinum-iridium C-ring for developing, characterized in that, Includes the following steps: Step 1: After peeling the platinum-iridium alloy rod, drill holes to prepare a platinum-iridium tube blank. Pass the platinum-iridium tube blank into the mandrel of the rolling mill and cold roll it to 6mm or less. Then perform multiple cold drawing passes, remove the mandrel, and obtain an ultra-fine platinum-iridium tube with an inner diameter of less than 0.61mm and a wall thickness of less than 0.05mm. Step 2: Use two femtosecond or picosecond lasers to cut the ultra-fine platinum-iridium tube multiple times. The lasers cut along two straight lines parallel to the axial direction of the ultra-fine platinum-iridium tube. The angle between the endpoints of the two straight lines on the same longitudinal section and the center of the longitudinal section is greater than 10°. The length of each cut is 15-50cm. Then, cut at both ends of the two parallel cutting lines to obtain a platinum-iridium tube with multiple long grooves. The spacing between two adjacent grooves is the same. Step 3: Under the protective atmosphere of inert gas, the platinum-iridium tubing from Step 2 is subjected to low-temperature annealing treatment at a temperature of 300-400℃ for 10-15 minutes to obtain the treated platinum-iridium tubing. Step 4: Cut the platinum-iridium tubing from Step 3 to obtain a C-ring; Step 5: Perform plasma cleaning on the C-ring from Step 4; Step 6: Immerse the C-ring cleaned in Step 5 into the polishing solution and apply direct current to perform plasma polishing on the C-ring. The polishing solution includes 0.5%-4% sulfate and 0.1%-2% complexing agent by mass. The temperature of the polishing solution is controlled at 70-100℃. After polishing, dry to obtain the C-ring platinum-iridium ring.

2. The method for preparing an ultra-precision platinum-iridium C-ring for development according to claim 1, characterized in that, The ultra-fine platinum-iridium tubes obtained in step 1 have an inner diameter of 0.2-0.6 mm and a wall thickness of 0.01-0.04 mm.

3. The method for preparing an ultra-precision platinum-iridium C-ring for development according to claim 1, characterized in that, In step 1, the cold rolling speed is 200 mm / min-300 mm / min, the mill feed speed is 2 mm-5 mm / pass, and the processing rate per rolling pass is 10-15%.

4. The method for preparing an ultra-precision platinum-iridium C-ring for development according to claim 1, characterized in that, The distance between the groove created in step 2 and the end of the ultra-fine platinum-iridium tube, and between two adjacent grooves, is 2-5 cm.

5. The method for preparing an ultra-precision platinum-iridium C-ring for development according to claim 1, characterized in that, In step 2, the angle between the endpoints of the two straight lines on the same longitudinal section and the center of the longitudinal section is 30°-120°.

6. The method for preparing an ultra-precision platinum-iridium C-ring for development according to claim 1, characterized in that, The cutting method in step 4 is femtosecond laser or picosecond laser cutting, the cutting direction is perpendicular to the pipe, and the distance between two cuts is less than 1mm.

7. The method for preparing an ultra-precision platinum-iridium C-ring for development according to claim 1, characterized in that, The process conditions of the plasma cleaning in step 5 are as follows: the vacuum degree is less than 10 -2 After the vacuum degree is less than 10 Pa, the argon-hydrogen mixed gas with a purity of 99.99% is filled at a flow rate of 5-15 SCCM. After the argon-hydrogen mixed gas is filled, the vacuum degree is 5-10 Pa, and the cleaning time is 400-600 s.

8. The method for preparing an ultra-precision platinum-iridium C-ring for development according to claim 1, characterized in that, The sulfate mentioned in step 6 is one or a mixture of ammonium sulfate, sodium sulfate, and zinc sulfate.

9. The method for preparing an ultra-precision platinum-iridium C-ring for development according to claim 1, characterized in that, The complexing agent mentioned in step 6 is one or a mixture of ethylenediaminetetraacetic acid tetrasodium, citric acid, and succinic acid.

10. The method for preparing an ultra-precision platinum-iridium C-ring for development according to claim 1, characterized in that, The DC voltage mentioned in step 6 is 260-300V, and the current density is 60-90A / dm. 2 .