CN112570715A - Structural member and processing method thereof - Google Patents

Structural member and processing method thereof Download PDF

Info

Publication number
CN112570715A
CN112570715A CN201910941020.1A CN201910941020A CN112570715A CN 112570715 A CN112570715 A CN 112570715A CN 201910941020 A CN201910941020 A CN 201910941020A CN 112570715 A CN112570715 A CN 112570715A
Authority
CN
China
Prior art keywords
structural member
temperature
structural
configuration
force
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN201910941020.1A
Other languages
Chinese (zh)
Other versions
CN112570715B (en
Inventor
常小龙
卢凌霄
辛晨
金旻
刘翔
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shanghai Weiwei Investment Holding Co ltd
Original Assignee
Shanghai Microport Medical Group Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shanghai Microport Medical Group Co Ltd filed Critical Shanghai Microport Medical Group Co Ltd
Priority to CN201910941020.1A priority Critical patent/CN112570715B/en
Publication of CN112570715A publication Critical patent/CN112570715A/en
Application granted granted Critical
Publication of CN112570715B publication Critical patent/CN112570715B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/10—Sintering only
    • B22F3/11—Making porous workpieces or articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/24—After-treatment of workpieces or articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y10/00—Processes of additive manufacturing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/24—After-treatment of workpieces or articles
    • B22F2003/247—Removing material: carving, cleaning, grinding, hobbing, honing, lapping, polishing, milling, shaving, skiving, turning the surface
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/24—After-treatment of workpieces or articles
    • B22F2003/248—Thermal after-treatment
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Powder Metallurgy (AREA)

Abstract

The invention relates to a processing method of a structural part, which comprises the following steps: performing additive manufacturing by using metal powder with shape memory characteristics to form a structural part with a first shape, wherein the structural part has a pore structure; applying an acting force on the structural part to deform the structural part with the first form so as to increase the size of a pore structure on the structural part and obtain a structural part with a second form; performing powder cleaning treatment on the structural part in the second form; and after the powder cleaning treatment, restoring the structural part in the second form to the first form. The structural member can be deformed to increase the size of the pore structure, and powder cleaning is carried out under the condition, so that the powder cleaning efficiency is greatly improved, the service performance of the structural member is improved, and the structural member can be restored to an initial state after the powder cleaning is finished, and the use of the structural member cannot be adversely affected.

Description

Structural member and processing method thereof
Technical Field
The invention relates to the technical field of additive manufacturing, in particular to a structural member and a processing method thereof.
Background
One implementation of metal additive manufacturing (also known as metal 3D printing) is to scan metal powder with a high-energy beam (laser beam or electron beam) to melt and cool the metal powder rapidly and accumulate the melted powder layer by layer to form a target structural member. However, this technique has some disadvantages, such as that a melting area and a heat affected area are formed when the metal powder is scanned by the high energy beam, the energy of the heat affected area is low to cause insufficient melting of the powder, and the insufficiently melted powder adheres to the periphery of the melting area to form a powder adhesion phenomenon; in the scanning process of the high-energy beam, due to the difference of printing parameters such as scanning speed and the like, a larger temperature gradient exists when the powder is melted, and a larger surface tension gradient is further generated, so that the melted powder flows from a low surface tension area to a high surface tension area, and a spheroidization phenomenon is formed due to the appearance of thick metal balls pointing to the center of the high-energy beam; in addition, for some suspended structures, the phenomenon of slag adhering occurs due to the action of gravity and capillary action in the printing process. These phenomena all lead to the presence of large amounts of free and unstable powders on the formed structures.
The presence of such powders can have an adverse effect on the later use of the structural member and therefore requires a dusting process after the structural member has been formed. However, for structural members with a large number of pores, such as a trabecular bone structure of a human body, an intervertebral fusion cage, etc., since the pore structure in such structural members has a small size (the pore diameter of part of the pores is 10um to 20um, or even smaller), when the conventional powder cleaning treatment process (such as a powder cleaning process of sand blasting, acid washing, ultrasonic vibration, etc.) is directly adopted for powder cleaning treatment, the powder in the pores is difficult to completely clean, and the usability of the structural members is further reduced.
Disclosure of Invention
The invention aims to provide a structural part and a processing method thereof, which aim to utilize metal powder to perform additive manufacturing to form the structural part with a pore structure and effectively remove powder remained in the structural part to improve the service performance of the structural part.
The structural member in the present invention refers to an article with a porous structure obtained by the processing method provided by the present invention, and the article can be any article made by additive manufacturing, and is particularly suitable for artificial implants used in the medical field.
In order to achieve the above object, the present invention provides a method for processing a structural member, the method comprising:
step S1: performing additive manufacturing by using metal powder with shape memory characteristics to form a structural part with a first shape, wherein the structural part has a pore structure;
step S2: applying a force to the structural member to deform the structural member having the first configuration to increase the size of the pore structure in the structural member to obtain a structural member having a second configuration;
step S3: performing powder cleaning treatment on the structural part in the second form;
step S4: and after the powder cleaning treatment, restoring the structural part in the second form to the first form.
Optionally, step 4 further comprises restoring the temperature of the structural member of the first configuration by changing the temperature of the structural member of the first configuration such that the structural member is fully transformed into a martensite phase or an austenite phase prior to or simultaneously with applying the force to the structural member. In this way, the recovery rate of the structural part after the deformation and powder cleaning operation can be maximized.
Optionally, changing the temperature of the structure of the first form comprises cooling the structure of the first form such that the temperature of the structure of the first form is below the martensitic finish temperature of the structure; or raising the temperature of the structural member of the first form so that the temperature of the structural member of the first form is higher than the martensite reverse transformation completion temperature of the structural member.
Optionally, the structure includes a first portion having the pore structure and, in the first configuration, the first portion exhibits an austenite phase, and the first portion is transformed into a martensite phase by reducing a temperature of the structure having the first configuration prior to or simultaneously with applying a force to the structure.
Optionally, the structural member further comprises a second portion, and in step S1, the process parameters for forming the first portion are different from the process parameters for forming the second portion, such that the second portion exhibits a martensite phase in the first form.
Optionally, before or after the step S3, the force is unloaded, and in the step S4, the first portion is returned to the first configuration by increasing the temperature of the structure having the second configuration.
Optionally, in the first configuration, the structure has a temperature below a martensitic reverse transformation end temperature, and prior to or simultaneously with applying a force to the structure, the structure having the first configuration is heated to a temperature above the martensitic reverse transformation end temperature and a force is applied to the structure to increase the size of the pore structure while maintaining the force to place the structure in the second configuration, the force being greater than a critical stress value for inducing a martensitic transformation.
Optionally, before the step S4 or in the step S4, the force is unloaded and the structure is returned to the first configuration by reducing the temperature of the structure having the second configuration.
Optionally, in the first configuration, the structure exhibits an austenite phase, and in step S2, the structure is in the second configuration by applying a force to the structure to increase the size of the pore structure while maintaining the force, the force being greater than a critical stress value to induce a martensitic transformation.
Optionally, the metal powder having shape memory properties includes at least one of Ni — Ti based shape memory alloy powder, Cu based shape memory alloy powder, and Fe based shape memory alloy powder.
Alternatively, the metal powder having a shape memory property is formed by mixing a base metal powder having no shape memory property and a modified powder including an element capable of changing the martensite start temperature of the base metal powder.
Optionally, the element capable of changing the martensitic transformation start temperature of the base metal powder includes at least one of V, Cr, Mn, Fe, Co, Pt, Pd, Au.
Alternatively, the metal powder having a shape memory property is formed by mixing a base metal powder having no shape memory property and a modified powder including an element capable of changing the martensite reverse transformation completion temperature of the base metal powder.
Optionally, before the step S2, the method further includes: heat treating the structural member of the first form.
Optionally, the structural member further comprises two or more clamping portions, and step 2 comprises applying a force to the clamping portions to deform the structural member having the first configuration.
Optionally, the machining method further comprises removing the clamping portion after step 4.
Optionally, when the structural member in the first form is formed, the method further includes: arranging a support body at a local position of the structural part; and after the heat treatment of the structural member of the first form, further comprising: and removing the support body.
Optionally, the powder cleaning treatment comprises at least one of sand blasting powder cleaning treatment, acid pickling powder cleaning treatment and ultrasonic powder cleaning treatment.
In order to achieve the above object, the present invention further provides a structural member having a pore structure, wherein the structural member is processed according to the processing method of the structural member as described in any one of the preceding items.
Compared with the prior art, the structural part and the processing method thereof have the following advantages:
the processing method of the structural part comprises the following steps: performing additive manufacturing by using metal powder with shape memory characteristics to form a structural part with a first shape; deforming the structural member having the first form to increase the size of the pore structure in the structural member to obtain a structural member having a second form; performing powder cleaning treatment on the structural part in the second form; and after the powder cleaning treatment, restoring the structural part in the second form to the first form. The method adopts metal powder with shape memory property to form the structural member, and utilizes the shape memory property or superelasticity of the shape memory alloy to change the shape of the structural member, thereby increasing the size of the pore structure, enabling the residual powder in the pores to be easily removed, and improving the service performance of the structural member.
Drawings
FIG. 1 is a flow chart of a method of forming a structural member according to an embodiment of the present invention;
fig. 2a is a schematic view of a structural member of a first form obtained by a method of manufacturing a structural member according to an embodiment of the present invention;
FIG. 2b is a schematic view of the construct shown in FIG. 2a in a second configuration;
fig. 3a is a schematic view of a structural member of a first form obtained by the method for manufacturing a structural member according to the second embodiment of the present invention;
figure 3b is a schematic view of the construct shown in figure 3a in a second configuration.
Detailed Description
The core idea of the invention is to provide a method for processing a structural member having a pore structure, as shown in fig. 1, the method comprising the steps of:
step S1: performing additive manufacturing by using metal powder with shape memory characteristics to form a structural part with a first shape;
step S2: applying an acting force on the structural part to deform the structural part with the first form so as to increase the size of a pore structure on the structural part and obtain a structural part with a second form;
step S3: performing powder cleaning treatment on the structural part in the second form;
step S4: and after the powder cleaning treatment, restoring the structural part in the second form to the first form.
In the present invention, the difference between the first form and the second form mainly means that the shape of the structural element is changed and the size of the pore structure is changed, in particular, the size of the pore structure is changed, i.e. when the structural element is in the second form, the size of the pore structure on the structural element is larger than the size of the pore structure in the first form.
The metal powder with the shape memory property is used as a raw material to manufacture the structural part with the shape memory property, and the reversible phase change property of the shape memory material is utilized to deform the structural part so as to increase the size of a pore structure. Therefore, after the size of the pore structure is enlarged, the pore structure can be conveniently and effectively cleaned, metal powder attached to the structural part is reduced, and the service performance of the structural part is improved. And then restoring the structural part to the initial form (namely, to the first form) after the powder cleaning treatment is finished.
Wherein, in the step S1, the metal powder with shape memory property includes, but is not limited to, Ni-Ti-based shape memory alloy powder, Cu-based shape memory alloy powder, Fe-based shape memory alloy powder, or other modified metal powder. The modified metal powder described herein can be obtained by mixing a powder of a base metal having no shape memory property with a powder of a particular substance. In some embodimentsWherein the special substance powder has a martensite start temperature M at which the base metal can be brought into a martensite statesA modified element, such as at least one of V, Cr, Mn, Fe, Co, Pt, Pd, Au, wherein the V, Cr, Mn, Fe, Co, etc. elements can make the martensite transformation start temperature M of the matrix metalsThe element Pt, Pd, Au, etc. can reduce the martensite transformation starting temperature M of the base metalsAnd (4) rising. Of course, for some martensitic transformation start temperatures M that will cause the base metal to be presentsElements such as Cu, Nb, etc., which remain unchanged, may also cause the base metal to exhibit shape memory properties. In other embodiments, the special substance powder has a martensitic reverse transformation end temperature A that enables the base metal to reverse transformfThe changed elements occur.
It will be appreciated that the martensitic transformation starting temperature M referred to hereinsRefers to the starting temperature for the transformation of the austenite phase to the martensite phase. Martensite finish temperature MfRefers to the finish temperature of the transformation of austenite phase to martensite phase. Martensite reverse transformation onset temperature AsRefers to the onset temperature of the transformation from the martensite phase to the austenite phase. Martensite inverse transformation end temperature AfThe temperature is the finishing temperature of the transformation from the martensite phase to the austenite phase, and the temperature value is as follows: mf < Ms < As < Af.
Further, the inventors of the present application have found that the structural member having the first form manufactured by the metal powder having the shape memory property may be in a martensite phase or an austenite phase, and may be in a state in which the martensite phase and the austenite phase coexist. When the structural member having the first form is in an austenite phase, the structural member may be deformed by applying an external force directly using its super elasticity, and if the structural member has a martensite phase or a martensite phase coexisting with the austenite phase, the structural member having the second form may be restored to a higher level of the restoration rate of the first form by changing the temperature of the structural member of the first form to completely transform the structural member into the martensite phase or the austenite phase before or while applying the force.
Therefore, it is preferable thatBefore or while applying the acting force to the structural member, the temperature of the structural member may be changed according to the specific condition of the structural member in the first form, and the structural member may be deformed by applying the acting force. For example, when the structural member having the first form is in a state in which a martensite phase and an austenite phase coexist, and is in the first form, the temperature of the structural member is lower than the martensite reverse transformation completion temperature afThe structure may be heated to a temperature above the martensite reverse transformation end temperature afSuch that the martensite transformation is all transformed to the austenite phase, and applying a force to the structure to increase the size of the pore structure.
Of course, when the structural member exhibits an austenite phase in the first configuration, the size of the pore structure may be increased by reducing the temperature of the structural member to transform the structural member to a martensite phase and then applying a force to the structural member to deform the structural member. Alternatively, the force may be applied directly to the structure to increase the size of the void structure.
In addition, when the form of the structural member is changed, it is possible to determine whether the entire structural member is changed or only a part of the structural member is changed according to the actual situation. For example, when the pore structure is distributed only in a part of the structural component, in the process of forming different parts by additive manufacturing, different forming parameters are set, so that different parts of the structural component have different phase transition temperatures, and thus only the part where the pore structure is formed can be deformed.
Preferably, after the structural member of the first form is formed by additive manufacturing, the formed structural member is usually subjected to a heat treatment to remove residual stress in the structural member, and the phase transition temperature of the structural member can be adjusted by selecting a suitable heat treatment manner and by adjusting and controlling parameters of the heat treatment.
In detail, the heat treatment may include a solution annealing heat treatment, and a main purpose of the solution annealing heat treatment is to remove residual stress in the structural member, so as to improve mechanical properties of the structural member and avoid quality problems of cracking, warping and the like of the structural member. Meanwhile, the solution annealing heat treatment can also reduce the temperature of the phase transformation point of the structural component. Taking Ni-Ti based shape memory alloy as a raw material to manufacture the structural member as an example, since the melting point of Ni is lower than that of Ti, a nickel compound generated during the formation of the structural member is dissolved and a uniform nickel component is generated during solution annealing, thereby lowering the phase transition temperature of the structural member.
Further, the heat treatment may also include an aging treatment, which in the present embodiment is performed after solution annealing, the main purpose of which is to increase the transformation temperature of the structural member. Still taking the Ni-Ti based shape memory alloy as the raw material to manufacture the structural member as an example, the percentage of Ti in the structural member increases due to the consumption of Ni during the aging process, thereby increasing the transformation point temperature of the structural member.
It will be appreciated that for some complex structural members (e.g. having a suspended structure), in order to ensure that the structural member can be formed smoothly during the additive manufacturing process, a support body needs to be disposed at a local position of the structural member, for example, at the position of the suspended structure, and the formation of the suspended structure is completed on the support body. After the heat treatment of the structural part is completed, the support body can then be removed by machining, for example by shearing directly with a vice.
In addition, in the step S3, the powder cleaning treatment includes, but is not limited to, at least one of sand blasting powder cleaning, acid cleaning and ultrasonic powder cleaning, and is selected according to the needs in practice. The step of cleaning the structural member by sandblasting refers to the step of spraying zirconia powder to the structural member from all directions, wherein the zirconia powder collides with the metal powder adhered to the structural member, and then the metal powder is peeled from the structural member. When the powder is cleaned by sand blasting, the particle size of the zirconia powder is between 10um and 65um, and the pressure of sand blasting is about 0.5 bar. The pickling powder cleaning refers to that the structural part is immersed in pickling solution, and the metal powder adhered to the structural part and the pickling solution are subjected to chemical reactionSo as to achieve the aim of removing powder. The pickling solution is usually made of sulfuric acid (H)2SO4) Hydrochloric acid (HCl) and hydrofluoric acid (HF) and, in addition, the pickling time should be controlled when pickling and cleaning are used. The ultrasonic powder cleaning is to apply ultrasonic vibration energy to the structural part and to make the metal powder adhered to the structural part fall off through high-frequency vibration. It is understood that the cleaning by sand blasting, acid cleaning or ultrasonic cleaning is a routine technique for those skilled in the art, and those skilled in the art can select appropriate parameters to complete the cleaning operation for a specific structural member.
In embodiments of the invention, the structural member is changeable from the first configuration to the second configuration and then from the second configuration to the first configuration based on shape memory effect or superelastic properties of the shape memory material.
Specifically, for the shape memory effect, a structural member having a specific shape is placed at an initial temperature, and when a parent phase of the structural member is a martensite phase and an austenite phase, the temperature of the structural member is lowered to a martensite finish temperature MfThe parent phase, namely the high-temperature phase participating in the martensite phase transformation, is completely transformed into the martensite phase, then the structural part is deformed by external force, and the deformation can be still maintained after the external force is unloaded; after the powder is cleaned, heating the structural part to the initial temperature of the structural part to recover the shape and the phase state of the structural part; when the parent phase of the structural member is only the austenite phase, the temperature is reduced and the structural member is deformed, and after the powder is cleaned, the structural member needs to be heated to the martensite reverse transformation starting temperature AsAs described above, the martensite starts to transform into austenite, and when the temperature of the structural member exceeds the martensite reverse transformation completion temperature AfThe martensite is completely transformed into austenite, and the structural member is restored to the parent phase shape.
For super elasticity, when the parent phase of the structural member is austenite phase, acting force can be directly applied to the structural member, and under the action of the acting force, the stress-strain relationship shows positive correlation change, when the value of the acting force reaches the critical stress value inducing martensite phase transformation, the martensite phase transformation starts,the austenite to martensite transformation (i.e., stress induced phase transformation). It will be appreciated that the martensite phase of the structure after transformation is unstable and that the structure can be transformed to recover its original shape when the force is removed. Alternatively, when the structure is in a state in which a martensite phase and an austenite phase coexist, or when the parent phase of the structure itself is a martensite phase, the structure may be heated to be at the martensite reverse transformation completion temperature afIn addition, the martensite is transformed into austenite, so that the super elasticity of the martensite can be utilized for cleaning, and the martensite is recovered to the initial temperature of the structural part after cleaning.
However, it should be noted that if the stress is increased after the martensite transformation begins, when the stress exceeds the stress value corresponding to the maximum recoverable strain of the material, the structural member will begin to deform plastically, resulting in irreversible strain. That is, in the case of performing the phase transition by utilizing the superelasticity, it is necessary to control the value of the applied stress within a suitable range. For embodiments of the present invention, the phase change of the first and second configurations of the structural member may be designed according to a particular utilized principle (i.e., shape memory effect or superelasticity).
To further clarify the objects, advantages and features of the present invention, the following detailed description is given in conjunction with specific embodiments of the invention. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.
Example one
The present embodiment utilizes the shape memory effect of the shape memory material to achieve the reversible deformation of the structural member, such that the structural member can be restored from the second configuration to the first configuration.
As shown in fig. 2a, the structural member 10 provided in this embodiment includes a first portion 11 and a second portion 12 connected to each other, where the first portion 11 has a plurality of pore structures, and the number of the pore structures is not limited, and may be one or more. Specifically, the method for processing the structural member of the present embodiment includes the steps of: step 1, step 2, step 3, step 4, step 5 and step 6.
Firstly, step 1: using equiatomic Ni — Ti alloy powder with a grain size of 20-50 um as a raw material and a laser beam as a heat source to perform additive manufacturing, for example, using Selective Laser Melting (SLM) to obtain a structural member 10 in a first form as shown in fig. 2a, the structural member in the first form has a substantially rectangular parallelepiped structure. When the structural member 10 is formed, a support (not shown) is provided at a partial portion of the structural member 10. Moreover, the whole forming process needs to be carried out under the protection of argon.
Different forming parameters are used in forming the first and second portions 11, 12 of the structural member 10. Specifically, the process parameters when forming the first portion 11 are as follows: the power of the laser beam was 270W, the scanning speed was 1050mm/s, the scanning interval was 75um, and the layer thickness of the single layer of metal powder was 75 um. When the second part 12 is formed, the power of the laser beam is 50W, the scanning speed is 220mm/s, the scanning interval is 90um, and the layer thickness of the single layer of metal powder is 50 um.
Then, step 2: and carrying out solution annealing heat treatment on the structural part 10, wherein the temperature of the solution annealing heat treatment is 900 ℃, the heat preservation time is 6 hours, then, the structural part is cooled to room temperature (for example, 25 ℃) along with a furnace, and argon gas is required to be filled for protection in the whole solution annealing heat treatment process.
At this point, the structural member 10 is still in the first configuration, and the first portion 11 of the structural member 10 exhibits an austenite phase and the second portion 12 of the structural member 10 exhibits a martensite phase. This is because the energy of the laser beam when forming the first portion 11 is different from the energy of the laser beam when forming the second portion 12, and in the first portion 11, the metallic Ni is partially vaporized so that the Ni component content becomes small in the first portion, and the Ti component content increases so that the phase transition point temperature of the first portion 11 is different from the phase transition point temperature of the second portion 12. The austenite to martensite transition termination temperature (i.e., the martensite transition termination temperature M) of the first portion 11 is determined by Differential Scanning Calorimetry (DSC)f) Is-20 ℃.
Then, step 3: and removing the support body by machining.
Then, step 4 is executed again: the structural member 10 is cooled until the temperature of the structural member 10 is below-20 c, at which time the austenite of the first portion 11 is fully transformed to martensite, and a force (shown as force F in fig. 2 b) is applied to the first portion 11 to structurally deform the first portion 11 to increase the size of the porosity in the first portion 11, resulting in a structural member 10 'of a second configuration, shown in fig. 2b, that is a generally cruciform configuration, and the force is relieved to maintain the structural member 10' in the second configuration. In this example, the deformation rate of the first part was 8%.
Then, step 5 is executed: the structure 10' in the second form is cleaned to remove powder from the pore structure in the first portion 11.
And finally, executing the step 6: the temperature of the structural member 10 'in the second form is raised at a rate of 10 ℃/min to restore the temperature of the structural member 10' to 25 ℃. The construct 10' in the second configuration substantially returns to the first configuration (i.e., as shown in fig. 2 a) due to the shape memory characteristics of the construct. In this embodiment, the recovery rate of the structural member is 95%, and the final molded size and shape are hardly affected, so that the processing accuracy can be ensured.
In step 4, the method for applying force may be to stretch both sides of the first portion 11 by a universal tensile testing machine, and more preferably, in order to protect the quality of the desired finished product from the clamping of the first portion 11 by the universal tensile testing machine, the structural member may further include two clamping portions respectively located on both sides of the first portion 11 for clamping by the universal tensile testing machine. After step 6, the two clamping portions may be removed by wire electrical discharge machining or the like to form the desired finished structure, which is not a limitation of the present invention.
During the above process, the second portion 12 of the structural member always presents a martensitic phase and no structural deformation occurs.
Testing the residual quantity of the particles in the finally obtained structural component, and measuring that the particles in the structural component are left as particles0.0009mg/cm2。
The structural member of this embodiment may be an intervertebral cage and the second site 12 may be a site that is not affected by temperature stimuli, such as a site that is in contact with bone tissue.
Comparative example 1
The structural member prepared in the comparative example has the same shape and size as the structural member prepared in the first embodiment, and in the preparation process, the raw materials, the SLM preparation process, the heat treatment process and the powder cleaning process adopted by the structural member and the SLM preparation process are the same.
The difference between this comparative example and the first example is that the structural part is cleaned directly after the support on the structural part 10 is removed.
The particle residue of the structural member in this comparative example was 0.002mg/cm as measured by the same test method as in example one2. Comparing the first example with the first comparative example, it can be seen that the powder cleaning efficiency in the first example is improved by 55%.
Example two
The present embodiment utilizes the shape memory effect of the shape memory material to achieve a reversible strain of the structural member to return the structural member from the second configuration to the first configuration.
As shown in fig. 3a, the present embodiment provides a structural member 20, which also has a plurality of pore structures. The method of manufacturing the structural member 20 includes the steps of: step 11, step 21, step 31, step 41, step 51, and step 61.
Step 11 is performed first: the isoatomic Ni-Ti alloy powder with a particle size of 25-45 um is used as a raw material to perform additive manufacturing to form the structural member 20 with a pore structure, and at this time, the structural member 20 is in a first form. In this embodiment, the SLM method is adopted to form the structural member 20, and the specific parameters are as follows: argon protection; the power of the laser beam is 245W, the scanning speed is 1200mm/s, and the scanning interval is 60 um; the layer thickness of the single layer of metal powder was 30 um.
Then, step 12 is executed: carrying out solution annealing heat treatment on the structural part 20, wherein the temperature of the solution annealing heat treatment is 920 ℃, the heat preservation time is 4.5h, and then the structural part is cooled along with the furnaceCooling to room temperature (specifically 25 ℃ in this example), and filling argon for protection during the whole solution annealing process. At this time, the structural member exhibits an austenite phase as a whole. The end temperature of the structure from austenite to martensite transformation (i.e. the martensite transformation end temperature M) is determined by DSC testf) Is-30 ℃. At this point, the construct 20 is still in the first configuration.
Then, step 13 is executed: and removing the support body arranged during molding.
Then step 14 is performed: the structure 20 is cooled until the temperature of the structure is below-30 c, at which time the structure exhibits a martensite phase. Applying a force (shown as F in fig. 3 b) to the structural member to deform the structural member 20 to increase the size of the pore structure in the structural member, wherein after the force is relieved, the structural member 20 is transformed into the second configuration shown in fig. 3b, and the deformation rate of the structural member is 6%.
Then, step 15 is executed: the second form of the structural member 20' is then cleaned in substantially the same manner as in the first embodiment.
Finally, step 16 is executed: the structure 20' is warmed up at a rate of 8 ℃/min and, under the effect of the shape memory properties of the structure, the structure substantially returns to the first configuration shown in figure 3 a. In this embodiment, the recovery rate of the structural member is almost 100%.
The particle residue in the structure was tested to be 0.00037mg/cm2. In particular, the structural member of the present embodiment may be an implant in the medical device industry, such as a trabecular disordered porous structure.
In this embodiment, the structural member 20 may also be provided with two or more than three clamping portions, and in step 14, a force is applied to the structural member by clamping the clamping portions, which may be removed as desired after step 16.
Comparative example No. two
The structural member prepared in the comparative example has the same shape and size as the structural member prepared in the first embodiment, and in the preparation process, the raw materials, the SLM preparation process, the heat treatment process and the powder cleaning process adopted by the structural member and the SLM preparation process are the same.
The difference between the comparative example and the first example is that the structural member is directly subjected to powder cleaning treatment after the support on the structural member is removed.
The structure of this comparative example was tested for particulate residue of 0.0023mg/cm using the same method as in example two2. Comparing the second example with the second comparative example, it is clear that the powder cleaning efficiency in the second example is improved by 83.91%.
EXAMPLE III
This embodiment utilizes superelasticity of the shape memory material to achieve reversible deformation of the structural member, thereby restoring the structural member from the second configuration to the first configuration. Therefore, when the structural element is in the second configuration, its temperature must be higher than the martensite reversion end temperature AfAnd maintaining an external force applied to the structure to maintain the structure in the second configuration. In addition, in view, the structural member of the first form in this embodiment is substantially the same as the structural member of the first form in the second embodiment, and the structural member of the second form is substantially the same as the structural member of the second form in the second embodiment, so that the specific shape of the structural member in this embodiment is still referred to fig. 3a and 3 b.
The processing method of the structural member in the embodiment is as follows:
firstly, Ni-Ti-based shape memory alloy powder rich in nickel is used as a raw material, additive manufacturing is carried out under the protection of argon gas to form a structural part, and the structural part obtained in the step is in the first form. The Ni-Ti-based shape memory alloy powder rich in Ni means that the Ni content in the Ni-Ti-based shape memory alloy powder is more than 50%, and the particle size of the Ni-Ti-based shape memory alloy powder in the embodiment is between 20um and 75 um. In this embodiment, the structural member is formed by an SLM method, and the specific process parameters of the SLM method are as follows: the power of the laser beam was 275W, the scanning speed was 1150mm/s, the scanning interval was 100um, and the layer thickness of the single layer of metal powder was 40 um.
Then, the structural member is heat treated. The heat treatment comprises two processes: the structural member is subjected to solution annealing heat treatment, and then subjected to aging treatment, so as to obtain the structural member of the first form at a normal temperature (specifically 25 ℃ in this embodiment). The conditions of the solution annealing are as follows: under the protection of argon, the temperature is 900 ℃, the heat preservation time is 6h, and then water quenching is carried out. The aging treatment conditions are as follows: vacuum environment, temperature 380 deg.C, holding for 16h, and water quenching. At this point, the structure is still in the first configuration.
The structural part in the first form presents a martensite phase, and DSC test is carried out on the structural part in the first form to obtain the martensite reverse transformation finishing temperature A of the structural partfThe temperature is 55 ℃, the critical stress value of induced martensite phase transformation is 500Mpa through the compression test, and the critical stress value of plastic strain is 1700 Mpa.
The structure is then heated to 65 ℃ at which time the structure assumes the austenite phase. Applying a force between 500Mpa and 1700Mpa, for example 1000Mpa, to the structural member and maintaining the force to deform the structural member to increase the size of the void structure in the structural member, whereby the structural member maintains the second shape. In this embodiment, the deformation rate of the structural member is 7%.
And then, performing powder cleaning treatment on the structural part in the second form.
And finally, unloading the acting force, and cooling the structural part to 25 ℃ to ensure that the structural part is basically recovered to the first form. In this embodiment, the recoverable strain of the structural member is 6.8%, the unrecoverable strain is 0.2%, and the recovery rate of the structural member is 97.14%.
The particle residue in the structure was tested to be 0.00042mg/cm2。
The structural member described in this embodiment may be an implant in the medical device industry, such as a trabecular bone-mimicking disordered porous structure.
Further, in practice, the phenomenon that the structural member needs to be cleaned for many times due to the fact that the cleaning condition is controlled improperly and the cleaning effect is poor at one time often occurs, and under the condition, the stable recovery rate of the structural member after deformation for many times needs to be considered.
In this regard, the present embodiment performs the deformation process on the structural member a plurality of times, i.e., repeats the following operations a plurality of times: heating the structural part in the first form, and loading stress to convert the structural part into a second form; and then unloading stress to the structural part in the second form and cooling to normal temperature to recover to the first form. Specifically, the deformation treatment was repeated 10 times in total, and after 10 times of deformation treatment, the recoverable strain of the structural member was 6.3%, and the unrecoverable strain was 0.7%, that is, the recovery rate of the structural member was 90%.
In this embodiment, the structural member may also be provided with two or more than three clamping portions, and the clamping portions may be used to apply a force to the structural member, and the clamping portions may be removed as required when the structural member is finally substantially restored to the first configuration.
Comparative example No. three
The structural member prepared in the comparative example is the same as the structural member prepared in the third embodiment in shape and size, and in the preparation process, the raw materials, the SLM preparation process, the heat treatment process and the powder cleaning process adopted by the structural member and the structural member are the same.
The difference between the comparative example and the first example is that the structural member is directly subjected to powder cleaning treatment after the support on the structural member is removed.
The same test method as in example three was used to obtain a particulate residue of 0.0018mg/cm in the structural member of this comparative example2. Comparing the third example with the third comparative example, it can be seen that the powder cleaning efficiency in the third example is improved by 76%.
Example four
This embodiment utilizes superelasticity of the shape memory material to achieve reversible deformation of the structural member, thereby restoring the structural member from the second configuration to the first configuration.
In this embodiment, the SLM method is still used to obtain the structural member, and then the structural member is subjected to heat treatment to obtain the structural member of the first form.
By regulating and controlling the technological parameters in the production process of the structural member (regulating and controlling the parameters when the structural member is formed by the SLM method in the embodiment), the martensite inverse transformation finishing temperature Af of the structural member is lower than the normal temperature (in the embodiment, the normal temperature refers to 25 ℃). That is, when the structural member is in the first configuration, the structural member fully exhibits an austenite phase at ambient temperatures. In this case, a force may be applied directly to the construct to deform the construct while maintaining the force to maintain the construct in the second configuration. And then, cleaning the structural part.
And after the powder cleaning is finished, the acting force is cancelled, and the structural part can be restored to the first shape.
In this embodiment, the structural member may also be provided with two or more than three clamping portions, and the clamping portions may be used to apply a force to the structural member, and the clamping portions may be removed as required when the structural member is finally substantially restored to the first configuration.
EXAMPLE five
In this embodiment, the SLM method is still used to obtain the structural member, and then the structural member is subjected to heat treatment to obtain the structural member of the first form.
When the martensite reverse transformation finishing temperature A of the structural memberfHigher than ordinary temperature (in this example, ordinary temperature means 25 ℃ C.), but the martensite finish temperature MfBelow room temperature, e.g. the martensite reverse transformation end temperature A of the structurefAt 55 ℃ and a martensitic transformation end temperature MfIs-20 ℃, and when the structural member is in the first form, the structural member exhibits a state in which austenite phase and martensite phase coexist at normal temperature. At this point, the structure is warmed to 65 ℃ at which time the structure assumes an austenite phase.
Applying a force between 500Mpa and 1700Mpa, for example 1000Mpa, to the structural member and maintaining the force to deform the structural member to increase the size of the void structure in the structural member, whereby the structural member maintains the second shape. In this embodiment, the deformation rate of the structural member is 7%.
And then, performing powder cleaning treatment on the structural part in the second form.
And finally, unloading the acting force, and cooling the structural part to 25 ℃ to ensure that the structural part is basically recovered to the first form.
In this embodiment, the structural member may also be provided with two or more than three clamping portions, and the clamping portions may be used to apply a force to the structural member, and the clamping portions may be removed as required when the structural member is finally substantially restored to the first configuration
In addition, in each of the above embodiments, the structural member is manufactured by the SLM method using Ni — Ti-based shape memory alloy powder as a raw material, and actually, the method of manufacturing the structural member using other metal powder having shape memory characteristics may be substantially the same as that in the above embodiments, and only the differences between the specific parameters are described. Of course, similar effects can be achieved by other additive manufacturing methods such as Electron Beam Melting (EBM).
Although the present invention is disclosed above, it is not limited thereto. Various modifications and alterations of this invention may be made by those skilled in the art without departing from the spirit and scope of this invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims (19)

1. A method of forming a structural member, the method comprising:
step S1: performing additive manufacturing by using metal powder with shape memory characteristics to form a structural part with a first shape, wherein the structural part has a pore structure;
step S2: applying a force to the structural member to deform the structural member having the first configuration to increase the size of the pore structure in the structural member to obtain a structural member having a second configuration;
step S3: performing powder cleaning treatment on the structural part in the second form;
step S4: and after the powder cleaning treatment, restoring the structural part in the second form to the first form.
2. The method of claim 1, wherein the step S4 further comprises returning the temperature of the structural member to the temperature of the first configuration by changing the temperature of the structural member in the first configuration to completely transform the structural member to the martensite phase or the austenite phase before or while applying the force to the structural member.
3. The method of manufacturing a structural member of claim 2, wherein changing the temperature of the structural member of the first form comprises cooling the structural member of the first form such that the temperature of the structural member of the first form is below a martensitic transformation end temperature of the structural member; or raising the temperature of the structural member of the first form so that the temperature of the structural member of the first form is higher than the martensite reverse transformation completion temperature of the structural member.
4. A method of manufacturing a structural component according to claim 3, wherein the structural component comprises a first portion having the pore structure and, in the first configuration, the first portion exhibits an austenite phase, and wherein the first portion is transformed into a martensite phase by reducing the temperature of the structural component having the first configuration prior to or simultaneously with the application of force to the structural component.
5. The method of manufacturing a structural member according to claim 4, wherein the structural member further comprises a second portion, and in the step S1, the process parameters for forming the first portion are different from the process parameters for forming the second portion, so that the second portion exhibits a martensite phase in the first form.
6. The method of fabricating a structure according to claim 4, wherein the force is unloaded before or after the step S3, and the first portion is restored to the first configuration by raising the temperature of the structure having the second configuration in the step S4.
7. A method of forming a structure according to claim 3, wherein in the first configuration the temperature of the structure is below the martensitic reverse transformation end temperature and prior to or simultaneously with the application of a force to the structure, the temperature of the structure is above the martensitic reverse transformation end temperature by heating the structure having the first configuration and applying a force to the structure to increase the size of the void structure while maintaining the force to place the structure in the second configuration, the force being above a critical stress value for inducing a martensitic transformation.
8. The method of fabricating a structure according to claim 7, wherein prior to the step S4 or in the step S4, the force is relieved, and the step S4 further comprises restoring the structure to the first configuration by reducing a temperature of the structure having the second configuration.
9. The method of fabricating a structural member according to claim 1, wherein in the first configuration, the structural member exhibits an austenite phase, and in step S2, the structural member is in the second configuration by applying a force to the structural member to increase the size of the pore structure while maintaining the force, the force being greater than a critical stress value for inducing a martensitic transformation.
10. The method of manufacturing a structural member according to claim 1, wherein the metal powder having a shape memory property includes at least one of Ni — Ti-based shape memory alloy powder, Cu-based shape memory alloy powder, and Fe-based shape memory alloy powder.
11. The method of manufacturing a structural member according to claim 1, wherein the metal powder having shape memory properties is obtained by mixing a base metal powder having no shape memory properties and a modified powder including an element capable of changing a martensite start temperature of the base metal powder.
12. The method of claim 11, wherein the element capable of changing the martensitic transformation starting temperature of the base metal powder comprises at least one of V, Cr, Mn, Fe, Co, Pt, Pd, Au.
13. The method of manufacturing a structural member according to claim 1, wherein the metal powder having shape memory properties is obtained by mixing a base metal powder having no shape memory properties and a modified powder including an element capable of changing a martensite reverse transformation completion temperature of the base metal powder.
14. The method of manufacturing a structural member according to claim 1, further comprising, before the step S2: heat treating the structural member of the first form.
15. The method of forming a structural member according to claim 14, wherein the step of forming the structural member in the first form further comprises: arranging a support body at a local position of the structural part; and after the heat treatment of the structural member of the first form, further comprising: and removing the support body.
16. The method of claim 1, wherein the structural member further comprises two or more clamping portions, and step 2 comprises applying a force to the clamping portions to deform the structural member having the first configuration.
17. The method of forming a structural member according to claim 16, further comprising removing the clamping portion after step 4.
18. The method of manufacturing a structural member according to any one of claims 1 to 17, wherein the dust removing treatment includes at least one of a sand blasting treatment, an acid pickling treatment, and an ultrasonic dust removing treatment.
19. A structural member having a porous structure, wherein the structural member is manufactured according to the method of manufacturing a structural member of any one of claims 1 to 18.
CN201910941020.1A 2019-09-30 2019-09-30 Structural member and processing method thereof Active CN112570715B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201910941020.1A CN112570715B (en) 2019-09-30 2019-09-30 Structural member and processing method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201910941020.1A CN112570715B (en) 2019-09-30 2019-09-30 Structural member and processing method thereof

Publications (2)

Publication Number Publication Date
CN112570715A true CN112570715A (en) 2021-03-30
CN112570715B CN112570715B (en) 2022-10-25

Family

ID=75116435

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201910941020.1A Active CN112570715B (en) 2019-09-30 2019-09-30 Structural member and processing method thereof

Country Status (1)

Country Link
CN (1) CN112570715B (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0382109A1 (en) * 1989-02-08 1990-08-16 Nivarox-FAR S.A. Process for treating a work piece made from a metallic shape memory alloy offering two states of reversible shape memory
CN109317677A (en) * 2018-10-16 2019-02-12 北京星航机电装备有限公司 A kind of honeycomb sandwich construction prepared by increasing material manufacturing method
CN209091745U (en) * 2018-10-30 2019-07-12 上海微创心通医疗科技有限公司 Split type heart valve bracket and its prosthese
CN110193940A (en) * 2019-05-30 2019-09-03 西安增材制造国家研究院有限公司 Powder cleaning structure and powder removing method in a kind of increasing material manufacturing equipment
CN209377809U (en) * 2018-10-15 2019-09-13 上海微创心通医疗科技有限公司 A kind of heart valve prosthesis prosthese and its bracket

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0382109A1 (en) * 1989-02-08 1990-08-16 Nivarox-FAR S.A. Process for treating a work piece made from a metallic shape memory alloy offering two states of reversible shape memory
CN209377809U (en) * 2018-10-15 2019-09-13 上海微创心通医疗科技有限公司 A kind of heart valve prosthesis prosthese and its bracket
CN109317677A (en) * 2018-10-16 2019-02-12 北京星航机电装备有限公司 A kind of honeycomb sandwich construction prepared by increasing material manufacturing method
CN209091745U (en) * 2018-10-30 2019-07-12 上海微创心通医疗科技有限公司 Split type heart valve bracket and its prosthese
CN110193940A (en) * 2019-05-30 2019-09-03 西安增材制造国家研究院有限公司 Powder cleaning structure and powder removing method in a kind of increasing material manufacturing equipment

Also Published As

Publication number Publication date
CN112570715B (en) 2022-10-25

Similar Documents

Publication Publication Date Title
Andani et al. Mechanical and shape memory properties of porous Ni50. 1Ti49. 9 alloys manufactured by selective laser melting
Safaei et al. Additive manufacturing of NiTi shape memory alloy for biomedical applications: review of the LPBF process ecosystem
Saedi et al. The influence of heat treatment on the thermomechanical response of Ni-rich NiTi alloys manufactured by selective laser melting
JP3949228B2 (en) Method for processing shape memory alloy
US6106642A (en) Process for the improved ductility of nitinol
JP2018053362A (en) Monolithic nitinol alloy
CN107419154A (en) One kind has hyperelastic TiZrHfNbAl high-entropy alloys and preparation method thereof
EP1222901A2 (en) Medical devices and methods for their manufacture
US20070293939A1 (en) Fatigue resistant endoprostheses
Haberland et al. Visions, concepts and strategies for smart nitinol actuators and complex nitinol structures produced by additive manufacturing
Mohamed et al. Nickel-titanium shape memory alloys made by selective laser melting: a review on process optimisation
Petrousek et al. Influence of cryorolling on properties of L-PBF 316l stainless steel tested at 298K and 77K
JP2007510064A (en) Nitinol with long service life
CA2489431A1 (en) .beta. titanium compositions and methods of manufacture thereof
Morgan et al. Taking the art out of smart!-Forming processes and durability issues for the application of NiTi shape memory alloys in medical devices
JP2009536265A (en) Method for producing Ti-Ni functionally gradient alloy and Ti-Ni functionally graded alloy produced therefrom
Khademzadeh Precision additive manufacturing of NiTi shape memory parts using micro-laser powder bed fusion
CN112570715B (en) Structural member and processing method thereof
JP6740554B2 (en) Heat treatment method for α+β type titanium alloy
KR101976074B1 (en) Method for manufacturing biodegradable stent
JP5355972B2 (en) Stent manufacturing method
CN115125462A (en) Heat treatment method for improving stability of structure and performance of titanium alloy manufactured by laser additive
CN112935275A (en) Electron beam fuse additive manufacturing method of gradient TiNi shape memory alloy
Domashenkov et al. Selective laser melting of NiTi powder
CN114729423A (en) Super elastic nickel-titanium alloy wire and forming method thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
TA01 Transfer of patent application right

Effective date of registration: 20211025

Address after: 201203 room B08, 21 / F, Zhangjiang building, No. 289, Chunxiao Road, China (Shanghai) pilot Free Trade Zone, Pudong New Area, Shanghai

Applicant after: Shanghai Weiwei Investment Holding Co.,Ltd.

Address before: 201203 No. 1601 Zhangdong Road, Zhangjiang High-tech Park, Pudong New Area, Shanghai

Applicant before: SHANGHAI MICROPORT MEDICAL (GROUP) Co.,Ltd.

TA01 Transfer of patent application right
CB02 Change of applicant information

Address after: 201203 room B08, 21 / F, Zhangjiang building, No. 289, Chunxiao Road, China (Shanghai) pilot Free Trade Zone, Pudong New Area, Shanghai

Applicant after: Minimally invasive Investment Holdings Ltd.

Address before: 201203 room B08, 21 / F, Zhangjiang building, No. 289, Chunxiao Road, China (Shanghai) pilot Free Trade Zone, Pudong New Area, Shanghai

Applicant before: Shanghai Weiwei Investment Holding Co.,Ltd.

CB02 Change of applicant information
GR01 Patent grant
GR01 Patent grant