Method for preparing integral ceramic metal acetabulum by adopting additive manufacturing and product

Abstract

The invention belongs to the technical field of medical and industrial cross correlation, and particularly relates to a method for preparing an integral ceramic / metal acetabulum by adopting additive manufacturing, which comprises the following steps: S1, powder mixing: uniformly mixing alumina powder, zirconia powder and other additives; s2, performing three-dimensional modeling on the acetabulum; s3, 3D printing is conducted, specifically, an acetabulum blank is printed through a binder spray forming technology; s4, curing and sintering the acetabulum blank, namely curing, cleaning and sintering the printed acetabulum blank at high temperature, S5, smelting and pouring titanium alloy, namely putting the acetabulum and the titanium alloy into a vacuum induction furnace, and smelting the titanium alloy; and S6, post-treatment, wherein redundant materials are removed through various machining technologies. The method has the beneficial effects that the bonding strength of the ceramic acetabular lining and the metal acetabular prosthesis is enhanced, the acetabular toughness is improved, the acetabular thickness is reduced, and the acetabular diameter is increased; and the prepared novel acetabular product can effectively prolong the service life of the hip joint prosthesis and prevent a patient from suffering from joint revision surgery.

Description

Technical Field

[0001] The present invention belongs to the cross-related technical field of medicine and engineering, and specifically relates to a method and product for preparing an integral ceramic metal acetabulum by using additive manufacturing. Background Art

[0002] In recent years, with the deepening of the aging problem at home and abroad, the proportion of the elderly population has increased rapidly, and the number of bone and joint diseases has increased day by day. More and more patients need to undergo artificial joint replacement surgery. On the existing market, artificial joint prosthesis materials are mainly metal materials (cobalt-chromium alloy, titanium alloy, tantalum, etc.), polymer materials (polymer polyethylene, polyether ether ketone, etc.), and ceramic materials (aluminum oxide, zirconium oxide, etc.). Several materials form the following interfaces, namely: 1. The interface between the metal ball head and the metal liner. In the long-term friction and wear process, toxic metal ions are precipitated at this interface. Accumulation to a certain concentration in the human body will cause chronic lesions. At the same time, wear debris will induce osteolysis of the bone tissue around the prosthesis; 2. The interface between the metal or ceramic ball head and the polyethylene liner. Polyethylene liner prostheses are widely used for their stable quality and price advantages, low friction coefficient and wear rate, good mechanical properties and biocompatibility. However, the aging of polyethylene in the body fluid environment and the periprosthetic osteolysis and aseptic loosening caused by wear debris are still the main complications after total hip replacement and the main cause of prosthesis revision. 3. The interface between the ceramic ball head and the ceramic liner. The ceramic-to-ceramic load-bearing interface is used in total hip replacement. In addition to having higher hardness, better lubrication and better wear resistance, ceramic materials also have good biocompatibility and do not release toxic metal ions, making them especially suitable for young patients with high activity levels. However, the high brittleness of ceramics makes them easy to break, which is still a major factor affecting the life of ceramic joints. Studies have found that the incidence of alumina ceramic hip prosthesis fragmentation is about 2.4%-2.8%.

[0003] Whether it is a ceramic liner, a metal liner or a polyethylene liner, due to the strength and wear of the liner, the liner has a certain thickness, which greatly occupies the space of the femoral head, especially when using a small-sized acetabular prosthesis. The diameter of the femoral head prosthesis has to be designed to be smaller (such as 28mm or smaller 22mm). This reduces the contact area and increases wear. The small-diameter ball head is also prone to dislocation. It also affects the range of motion of the joint prosthesis and cannot meet the functional needs of the human body. Therefore, it is an inevitable requirement to improve the quality of life of patients to construct a new ceramic-to-ceramic artificial hip joint system with a large-sized ball head and an ultra-thin acetabular cup to increase the range of motion of the artificial hip joint, reduce the fragmentation of the liner ceramic, increase its service life, and prevent joint dislocation.

[0004] After searching the prior art literature, it was found that the publication number CN116549725A, entitled "3D printed metal and polymer polyethylene integrated hip prosthesis preparation method", discloses a 3D printed metal and polymer polyethylene integrated hip prosthesis preparation method, including the following steps: printing metal powder into a metal acetabular shell by 3D printing technology; mechanically activating the polyethylene powder, and evenly mixing it with Grubbs second-generation catalyst, vitamin E, and microcapsules, compounding it with the metal acetabular shell by injection molding and hot pressing, and then forming a polyethylene joint surface by turning to obtain the 3D printed metal and polymer polyethylene integrated hip prosthesis. Publication number CN107261212A, entitled "An integrated acetabular prosthesis and its preparation method", discloses a method for preparing an integrated acetabular prosthesis, including: consisting of a metal outer cup and an outer cup liner, firstly preparing the metal outer cup by various processing methods, and then constructing the outer cup liner on the metal outer cup body by additive manufacturing technology. The one-piece acetabular prosthesis is formed in one step, which allows for a precise combination of the two, reducing micro-movements, thereby reducing wear and reducing machining processes, which is beneficial for reducing costs. The above two prostheses still have an interface between the acetabular cup and the liner, and the liner material is high molecular polyethylene. In essence, it is still a hip joint prosthesis design with a metal-to-polyethylene interface, which cannot solve the aging and wear problems of polyethylene in a body fluid environment. Therefore, preparing a new type of high bonding strength, high wear resistance, high toughness, large diameter, lightweight metal-ceramic gradient composite integrated acetabulum is a good choice in this field. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides a method and product for preparing an integral ceramic / metal acetabulum by additive manufacturing, which has the following advantages: (1) First, 3DP printing technology can print a ceramic acetabulum liner with a complex gradient porous structure and a solid body with high precision, and the composition and performance of the acetabulum liner are comparable to the surgical implant powder ceramics that are currently successfully used in business, so there is no need to consider the problems of component mismatch and insufficient precision. (2) Second, pouring titanium alloy into a three-dimensional gradient porous structure can achieve a physical interlocking structure, and titanium alloy can react with ceramics to form a metallurgical bond, achieving a dual physical and metallurgical bond. Compared with the traditional mechanical locking and taper locking acetabulum, it has a stronger bonding ability and is less likely to fall off during use, reducing the risk of secondary surgery. (3) Since the contact part between the metal-ceramic acetabular cup and the ball head prepared by the method has only a thin layer of solid ceramic, and the remaining part is in the form of ceramic and titanium alloy interlaced, and presents a gradient structure from inside to outside, this leads to a good transition from ceramic to metal in the entire acetabulum. Compared with the traditional direct connection between the ceramic liner and the metal prosthesis, there is no interface between the ceramic liner and the metal prosthesis, which has better toughness and is not easy to break when subjected to external force. (4) Since the traditional ceramic liner and metal prosthesis need to be locked by taper, the ceramic liner needs to be made thicker, which is convenient for manufacturing, ensures the strength of the ceramic liner and is conducive to the fixation of the two. Therefore, the thickness of the entire acetabular cup is relatively large. The method of the present invention can prepare the ceramic liner and the metal acetabular cup prosthesis as a whole, thereby reducing the thickness of the acetabulum and increasing the diameter of the acetabular cup, freeing up space for increasing the diameter of the ball head, overcoming the disadvantage of the small diameter ball head being easy to dislocate in the prior art, thereby extending the service life of the hip joint prosthesis and saving patients from the pain of joint revision surgery.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A method for preparing a monolithic ceramic / metal acetabulum by additive manufacturing comprises the following steps:

[0008] S1: powder mixing, uniformly mixing alumina powder, zirconium oxide powder and other additives;

[0009] S2: 3D modeling of acetabulum, using 3D software to build an acetabulum model consisting of a cavity and a gradient porous ceramic liner;

[0010] S3: 3D printing, using binder jet forming technology to print the acetabulum blank;

[0011] S4: Acetabular blank solidification and sintering, solidification, cleaning and high-temperature sintering of the printed acetabular blank;

[0012] S5: melting and pouring of titanium alloy, placing the acetabulum and the titanium alloy into a vacuum induction furnace, melting the titanium alloy, and pouring the titanium alloy into the acetabulum cavity under vacuum;

[0013] S6 post-processing, remove excess material through various processing techniques, and process and polish the acetabulum.

[0014] In a preferred embodiment, in step S1, the composition and proportion of the powder are as follows: Al with a particle size of D50 = 10-20 μm and a purity of ≥ 99.9% 2 O 3 The powder accounts for 70-80wt% of the total amount, the particle size is D50=10-20μm, and the purity is ≥99.9% ZrO 2 The powder accounts for 20-30wt% of the total amount, and other additives include MnO 2 Cr 2 O 3 The particle size is D50=10-20μm, the purity is ≥99.9%, the total amount is ≤5wt%, and the impurity content is ≤0.2wt%. These powders are put into a powder mixer according to the above proportion and mixed at a speed of 25-35r / min for 3-5h.

[0015] In a preferred embodiment, in step S2: an acetabulum model is drawn using three-dimensional modeling software, and the model is divided into: an acetabulum solid liner, an acetabulum porous liner, a titanium alloy casting cavity, and a titanium alloy casting pouring cup, wherein the thickness of the acetabulum solid liner is 0.5 to 1 mm; the acetabulum porous liner is a gradient porous structure with a thickness of 1 to 3 mm, and its porosity varies from 10% to 20% to 80% to 90% from close to the solid liner to the titanium alloy casting cavity, and the pores are three-dimensional through holes that are interconnected and have polygonal, circular or irregular shapes.

[0016] In a preferred embodiment, in step S3: first, the drawn three-dimensional model is exported in stl file format, sliced ​​in slicing software, and then converted into G code and sent to the printer, and the model is printed using a powder bed binder jet forming printer, the binder is a phenolic resin ethanol solution, the binder saturation is 100-140%, and the printing layer height is 80-120 μm.

[0017] In a preferred embodiment, in step S4: first, the printed body together with the uncured powder is placed in a drying oven at 180-220°C for curing for 2-4 hours, and then the excess powder is removed. Finally, the body is placed in a high-temperature sintering furnace for sintering at a sintering temperature of 1300-1500°C for 1-3 hours, and then cooled in the furnace after sintering.

[0018] In a preferred embodiment, in step S5: the titanium alloy and the blank are placed in a vacuum induction furnace together, the pouring cup of the blank is facing the pouring mouth of the crucible, wherein the grade of the titanium alloy is one of pure titanium, TC4, TC6, and TA15, and then vacuuming and induction heating are performed, and the vacuum degree is 3*10 -6 ~2.0*10 -4 MPa, the heating temperature is 1700-2000℃, after the titanium alloy is melted, the crucible is tilted to pour the liquid titanium alloy from the pouring cup into the blank cavity.

[0019] In a preferred embodiment, in step S6: a cutting machine is used to cut off excess ceramic and titanium alloy to obtain an acetabulum blank, and the acetabulum blank is ground and polished using sandpaper and polishing cloth to make the roughness of the ceramic liner and the ball head less than Ra0.025, and the outer surface of the titanium alloy part is a porous structure sprayed with hydroxyapatite.

[0020] In a preferred embodiment, a new metal-gradient porous ceramic integral acetabulum product is obtained by a 3D printing gradient porous ceramic acetabulum preparation method.

[0021] Compared with the prior art, the above technical scheme conceived by the present invention first prepares a ceramic acetabular cavity with a gradient porous structure lining by 3D printing technology, and then vacuum casts a high-temperature titanium alloy liquid, and achieves an excellent combination of a metal acetabular prosthesis and an acetabular ceramic liner after solidification. The present invention fully utilizes the advantages of 3D printing and the characteristics of metal-ceramic gradient materials, and has the beneficial effects of enhancing the bonding strength of the ceramic acetabular liner and the metal acetabular prosthesis, improving the toughness of the acetabulum, reducing the thickness of the acetabulum and increasing the diameter of the acetabular cup, effectively extending the service life of the hip prosthesis, reducing the risk of postoperative joint dislocation and saving patients from the pain of joint revision surgery. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a process flow chart of a method for preparing an integral ceramic metal acetabulum by additive manufacturing and a product of the present invention;

[0023] Figure 2 It is a three-dimensional schematic diagram of the ceramic acetabulum printed by the present invention.

[0024] Figure 3 It is a schematic diagram of the gradient porous lining printed by the present invention.

[0025] Figure 4 It is a schematic diagram of the metal-ceramic integral acetabulum prepared by the present invention. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0027] See also Figure 1 , Figure 2 , Figure 3 , Figure 4 The preferred embodiment of the present invention provides a method and product for preparing an integral ceramic / metal acetabulum by additive manufacturing. The present invention first prepares a ceramic acetabulum cavity with a gradient porous structure lining by 3D printing technology, and then vacuum casts a high-temperature titanium alloy liquid. After solidification, an excellent combination of a metal acetabulum prosthesis and an acetabulum ceramic liner is achieved. The present invention fully utilizes the advantages of 3D printing and the characteristics of metal-ceramic gradient materials, and has the beneficial effects of enhancing the bonding strength of the ceramic acetabulum liner and the metal acetabulum prosthesis, improving the toughness of the acetabulum, reducing the thickness of the acetabulum and increasing the diameter of the acetabulum cup. The prepared new acetabulum product can effectively extend the service life of the hip joint prosthesis and save patients from the pain of joint revision surgery.

[0028] Embodiment 1:

[0029] A method for preparing a monolithic ceramic / metal acetabulum by additive manufacturing and a product process of Example 1 are as follows Figure 1 As shown, the specific process is as follows:

[0030] The first step: powder mixing, that is, using a powder mixer to evenly mix alumina powder, zirconium oxide powder and other additives. Among them, the main component is Al with a purity of ≥99.9%. 2 O 3 Powder, accounting for 75wt% of the total powder, with a particle size of D50 = 15μm. The secondary component is ZrO with a purity of ≥99.9% 2 Powder, accounting for about 22wt% of the total powder, with a particle size of D50 = 10-20μm. Other additives are also needed, including sintering aid MnO 2 and colorant Cr 2 O 3 , their particle size is D50 = 15 μm, purity ≥ 99.9%, sintering aid MnO 2 1wt% of the total powder mass, colorant Cr 2 O 3 The content of impurities is 0.1 wt %. The powders are put into a powder mixer at the above ratio and mixed at a speed of 30 r / min for 4 hours.

[0031] Step 2: 3D modeling of acetabulum. Use 3D software to build an acetabulum model consisting of a cavity and a gradient porous ceramic liner. The model is divided into the following parts: acetabulum solid liner, acetabulum porous liner, titanium alloy casting cavity, ceramic shell, titanium alloy casting pouring cup, bottom plate, etc. Figure 2 The thickness of the acetabular solid liner is 0.8 mm. The acetabular porous liner is a gradient porous structure, as shown in the schematic diagram. Figure 3 The thickness of the gradient porous ceramic lining is 2 mm, and its porosity varies from 15% to 85% from the solid lining to the titanium alloy casting cavity. The pores are three-dimensional through holes that are interconnected and have a quadrilateral shape.

[0032] Step 3: 3D printing. Export the drawn 3D model in stl file format, slice it in the slicing software, and then convert it into G code and send it to the printer. Use a powder bed binder jet forming printer (3DP) to print the model. The binder is phenolic resin ethanol solution with a binder saturation of 120%. The printing layer height is 100μm.

[0033] Step 4: Acetabular blank curing and sintering. The printed blank and the uncured powder are placed in a drying oven at 200°C for curing for 3 hours, and then the excess powder is removed. Finally, the blank is placed in a high-temperature sintering furnace for sintering at a temperature of 1400°C for 2 hours, and then cooled in the furnace after sintering.

[0034] Step 5: Titanium alloy melting and pouring. Put the titanium alloy and the blank into the vacuum induction furnace together. The pouring cup of the blank needs to face the pouring cup of the crucible. The grade of the titanium alloy is TC4. Then vacuumize and induction heat. The vacuum degree is 2.0*10 -5 MPa, and the heating temperature is 1800°C. After the titanium alloy is melted, the crucible is tilted to pour the liquid titanium alloy from the pouring cup into the blank cavity.

[0035] Step 6: Post-processing. Use a cutting machine to cut off the excess ceramic and titanium alloy to obtain the acetabulum blank. Use sandpaper and polishing cloth to grind and polish the acetabulum blank to make the roughness of the ceramic liner and ball head reach Ra0.012. The outer surface of the titanium alloy part is a porous structure sprayed with hydroxyapatite. Finally, a new metal-gradient porous ceramic integrated acetabulum is obtained based on the 3D printing gradient porous ceramic acetabulum preparation method, as shown in the schematic diagram. Figure 4 shown.

[0036] Embodiment 2:

[0037] A method for preparing a monolithic ceramic / metal acetabulum by additive manufacturing and a product process of Example 2 are as follows Figure 1 As shown, the specific process is as follows:

[0038] The first step: powder mixing, that is, using a powder mixer to evenly mix alumina powder, zirconium oxide powder and other additives. Among them, the main component is Al with a purity of ≥99.9%. 2 O 3 Powder, accounting for 80wt% of the total powder, with a particle size of D50 = 17μm. The secondary component is ZrO with a purity of ≥99.9% 2Powder, accounting for about 17wt% of the total powder, with a particle size of D50 = 14μm. Other additives need to be added, including sintering aid MnO 2 and colorant Cr 2 O 3 Their particle size is D50 = 14 μm, purity ≥ 99.9%, sintering agent MnO 2 Accounting for 1.2wt% of the total mass of the powder, the colorant Cr 2 O 3 The content of impurities is 0.1 wt % and the powders are put into a powder mixer at the above ratio and mixed at a speed of 30 r / min for 4 hours.

[0039] Step 2: 3D modeling of acetabulum. Use 3D software to build an acetabulum model consisting of a cavity and a gradient porous ceramic liner. The model is divided into the following parts: acetabulum solid liner, acetabulum porous liner, titanium alloy casting cavity, ceramic shell, titanium alloy casting pouring cup, bottom plate, etc. Figure 2 The thickness of the acetabular solid liner is 1 mm. The acetabular porous liner is a gradient porous structure, as shown in the schematic diagram. Figure 3 The thickness of the gradient porous ceramic lining is 1.8 mm, and its porosity varies from 10% to 80% from the solid lining to the titanium alloy casting cavity. The pores are three-dimensional through holes that are interconnected and have a quadrilateral shape.

[0040] Step 3: 3D printing. Export the drawn 3D model in stl file format, slice it in the slicing software, and then convert it into G code and send it to the printer. Use a powder bed binder jet forming printer (3DP) to print the model. The binder is phenolic resin ethanol solution with a binder saturation of 130%. The printing layer height is 90μm.

[0041] Step 4: Acetabular blank curing and sintering. The printed blank together with the uncured powder is placed in a drying oven at 220°C for curing for 2.5 hours, and then the excess powder is removed. Finally, the blank is placed in a high-temperature sintering furnace for sintering at a temperature of 1500°C for 1.5 hours, and then cooled in the furnace after sintering.

[0042] Step 5: Titanium alloy melting and pouring. Put the titanium alloy and the blank into the vacuum induction furnace together. The pouring cup of the blank needs to face the pouring cup of the crucible. The grade of the titanium alloy is pure titanium alloy. Then vacuumize and induction heat. The vacuum degree is 3.0*10 -6 MPa, and the heating temperature is 2000°C. After the titanium alloy is melted, the crucible is tilted to pour the liquid titanium alloy from the pouring cup into the blank cavity.

[0043] Step 6: Post-processing. Use a cutting machine to cut off the excess ceramic and titanium alloy to obtain the acetabulum blank. Use sandpaper and polishing cloth to grind and polish the acetabulum blank to make the roughness of the ceramic liner and ball head reach Ra0.012. The outer surface of the titanium alloy part is a porous structure sprayed with hydroxyapatite. Finally, a new metal-gradient porous ceramic integrated acetabulum is obtained based on the 3D printing gradient porous ceramic acetabulum preparation method, as shown in the schematic diagram. Figure 4 shown.

[0044] The invention provides a method and product for preparing an integral ceramic / metal acetabulum by additive manufacturing. A ceramic acetabulum cavity with a gradient porous structure lining is prepared by 3D printing technology, and then a high-temperature titanium alloy liquid is vacuum poured. After solidification, an excellent combination of a metal acetabulum prosthesis and an acetabulum ceramic liner is achieved. The invention makes full use of the advantages of 3D printing and the characteristics of metal-ceramic gradient materials, and has the beneficial effects of enhancing the bonding strength between the ceramic acetabulum liner and the metal acetabulum prosthesis, improving the toughness of the acetabulum, reducing the thickness of the acetabulum and increasing the diameter of the acetabulum cup. The prepared new acetabulum product can enable patients undergoing hip replacement for the first time to retain more bone mass, effectively prolong the service life of the hip prosthesis and save patients from the pain of joint revision surgery.

[0045] The above is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be considered as the protection scope of the present invention. The structures, devices and operating methods not specifically described and explained in the present invention shall be implemented according to the conventional means in the art unless otherwise specified and limited.

Claims

1. A method for preparing a monolithic ceramic / metal acetabulum by additive manufacturing, characterized in that: The following steps are involved: S1: powder mixing, uniformly mixing alumina powder, zirconium oxide powder and other additives; S2: 3D modeling of acetabulum, using 3D software to build an acetabulum model consisting of a cavity and a gradient porous ceramic liner; S3: 3D printing, using binder jet forming technology to print the acetabulum blank; S4: Acetabular blank solidification and sintering, solidification, cleaning and high-temperature sintering of the printed acetabular blank; S5: melting and pouring of titanium alloy, placing the acetabulum and the titanium alloy into a vacuum induction furnace, melting the titanium alloy, and pouring the titanium alloy into the acetabulum cavity under vacuum; S6 post-processing, remove excess material through various processing techniques, and process and polish the acetabulum.

2. A method for preparing a monolithic ceramic / metal acetabulum by additive manufacturing according to claim 1, characterized in that: In step S1: the composition and proportion of the powder are as follows: Al2O3 powder with a particle size of D50 = 10-20μm and a purity of ≥99.9% accounts for 70-80wt% of the total amount, ZrO2 powder with a particle size of D50 = 10-20μm and a purity of ≥99.9% accounts for 20-30wt% of the total amount, and other additives include MnO2 and Cr2O3, with a particle size of D50 = 10-20μm and a purity of ≥99.9%, and a total amount of ≤5wt%, and an impurity content of ≤0.2wt%. These powders are placed in a powder mixer according to the above proportions and mixed at a speed of 25-35r / min for 3-5h.

3. A method for preparing a monolithic ceramic / metal acetabulum by additive manufacturing according to claim 1, characterized in that: In step S2: use three-dimensional modeling software to draw an acetabulum model, the model is divided into: acetabulum solid liner, acetabulum porous liner, titanium alloy casting cavity, titanium alloy casting pouring cup, wherein the thickness of the acetabulum solid liner is 0.5-1mm; the acetabulum porous liner is a gradient porous structure with a thickness of 1-3mm, and its porosity changes from 10%-20% to 80%-90% from close to the solid liner to the titanium alloy casting cavity, and the pores are three-dimensional through holes that penetrate each other, and the shape is polygonal, circular or irregular.

4. The method for preparing a monolithic ceramic / metal acetabulum by additive manufacturing according to claim 1, characterized in that: In step S3: first, the drawn 3D model is exported in stl file format, sliced ​​in slicing software, and then converted into G code and sent to the printer. The model is printed using a powder bed binder jet forming printer. The binder is a phenolic resin ethanol solution, the binder saturation is 100-140%, and the printing layer height is 80-120 μm.

5. The method for preparing a monolithic ceramic / metal acetabulum by additive manufacturing according to claim 1, characterized in that: In step S4: first, the printed body together with the uncured powder is placed in a drying oven at 180-220°C for curing for 2-4 hours, and then the excess powder is removed. Finally, the body is placed in a high-temperature sintering furnace for sintering at a sintering temperature of 1300-1500°C for 1-3 hours, and then cooled in the furnace after sintering.

6. The method for preparing a monolithic ceramic / metal acetabulum by additive manufacturing according to claim 1, characterized in that: In step S5, the titanium alloy and the blank are placed in a vacuum induction furnace, the pouring cup of the blank is facing the pouring mouth of the crucible, wherein the grade of the titanium alloy is one of pure titanium, TC4, TC6, and TA15, and then vacuuming and induction heating are performed, and the vacuum degree is 3*10 -6 ~2.0*10 -4 MPa, the heating temperature is 1700-2000℃, after the titanium alloy is melted, the crucible is tilted to pour the liquid titanium alloy from the pouring cup into the blank cavity.

7. The method for preparing a monolithic ceramic / metal acetabulum by additive manufacturing according to claim 1, characterized in that: In step S6: use a cutting machine to cut off excess ceramic and titanium alloy to obtain an acetabulum blank, use sandpaper and polishing cloth to grind and polish the acetabulum blank so that the roughness of the ceramic liner and the ball head is less than Ra0.025, and the outer surface of the titanium alloy part is a porous structure sprayed with hydroxyapatite.

8. A novel metal-gradient porous ceramic integral acetabulum product obtained by using the 3D printing-based gradient porous ceramic acetabulum preparation method as described in any one of claims 1 to 7.

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