Dry pump manufacturing process based on metal 3D printing technology

Abstract

The invention discloses a dry pump manufacturing process based on a metal 3D printing technology, and relates to the technical field of metal 3D printing additive manufacturing of dry pumps. Comprising the following steps: designing a dry pump rotor and a dry pump cavity structure; selecting a metal 3D printing material; a dry pump cavity and a solid or hollow dry pump rotor are machined through metal 3D printing; then the inner surface of the dry pump cavity and the outer surface of the rotor are subjected to finish machining calibration; other standard parts such as a sealing kit, a buckle, a bearing, a gear and the like of the dry pump are processed by adopting a technology or directly purchased; all the parts are assembled into the dry pump, and inspection and experiment are carried out. The 3D metal printing additive manufacturing technology is adopted, weight reduction and one-time forming machining of the cooling water pipeline and the nitrogen purging pipeline are achieved according to optimal design of materials and structures, and the high temperature resistance, corrosion resistance, friction resistance and dust contamination prevention capacity of the dry pump are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal 3D printing manufacturing of dry pumps, and particularly to a manufacturing process of dry pumps based on metal 3D printing technology. Background Art

[0002] A dry pump is a device that realizes vacuum and does not require oil or other working media to extract gas and directly discharge it to the atmosphere. Since the dry pump technology was invented by Edwards Company in the UK in 1986, the way of generating vacuum and its application in industrial production has undergone a huge change. Because dry pumps can be used in production systems with strict cleanliness requirements, corrosive gases, humidity, and dust, they have become the preferred key equipment on the semiconductor production line.

[0003] In order to efficiently extract gas, the gaps between rotors and between the rotor and the pump body cavity are generally as small as a few hundred to dozens of micrometers or even smaller. Due to the compression of the pumped gas and the high-speed rotation of the rotor, the temperature in the pump cavity will reach a level of one hundred and dozens to two hundred degrees Celsius. Metal thermal expansion and dust adhesion in the pumped gas will cause friction and even jamming between the rotors and between the rotor and the pump cavity. Therefore, high requirements are imposed on the materials and machining accuracy of dry pump components.

[0004] In order to achieve the cooling of the dry pump and blow out the dust, cooling water pipelines and hot nitrogen pipelines also need to be arranged in the pump cavity, which complicates the structure of the pump cavity and makes it difficult to achieve a perfect design through casting technology. On the other hand, since the profiles of the rotors are all composed of complex curved surfaces, high requirements are also imposed on precision machining technology, and usually, a 4-axis or 5-axis machining center is required for long-time machining to complete.

[0005] The general requirements for dry pumps that meet the needs of the semiconductor production line include: the metal material should be corrosion-resistant and high-temperature resistant; the structural design and machining technology should ensure that there is no tooth collision interference problem under micrometer-level meshing clearances; the precise machining of complex structures of components should be achieved with high precision; the assembly technology requires extremely small assembly and adjustment errors; the sealing technology is more stringent, and the shaft end needs to be sealed without oil leakage; in terms of cooling technology, a delicate cooling structure is required to reduce the temperature in the pump cavity and the rotor; the special requirements for dry pumps that meet the needs of the semiconductor production line include: the gases in the semiconductor production line can be toxic, flammable, explosive, and corrosive, and the dry pump must not react with the gases. At the same time, since a breakdown shutdown will cause huge economic losses to the semiconductor production line, the requirements for the working stability, reliability, and controllability of the dry pump are particularly high, and it can only be used in the production line after passing the stringent verification and assessment of the semiconductor production line.

[0006] The domestic mass substitution of dry pump manufacturing has not been fully realized yet. Summary of the Invention

[0007] The object of the present invention is to solve the disadvantages existing in the prior art, and a dry pump manufacturing process based on metal 3D printing technology is proposed.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A dry pump manufacturing process based on metal 3D printing technology includes the following steps:

[0010] S1: Design the dry pump rotor and the dry pump cavity structure;

[0011] S2: Select metal 3D printing materials;

[0012] S3: Through metal 3D printing, print to form a dry pump cavity;

[0013] S4: Through metal 3D printing, print to form a solid or hollow dry pump rotor;

[0014] S5: The inner surface of the dry pump cavity and the outer surface of the rotor completed by metal 3D printing are subjected to final calibration machining and surface polishing on a machining center;

[0015] S6: The sealing kit, buckle and other standard components of the dry pump are directly processed or purchased by using conventional precision machining technology;

[0016] S7: Assemble all the above components into a dry pump and conduct inspection.

[0017] Preferably: In S3, when printing the cavity, a spiral or fold-back type cooling water flow pipeline, a hot nitrogen dust purge pipeline, a dust collection cavity, the position of a pressure relief valve, and the installation position of an embedded monitoring sensor and its signal cable pipeline are formed in the cavity;

[0018] The dust collection cavity is arranged at the air outlet of the dry pump cavity, and the dry pump cavity is also equipped with a matching sealing cover.

[0019] Preferably: In the dry pump manufacturing process, after forming a spiral or fold-back type cooling water flow pipeline and a hot nitrogen dust purge pipeline, using the formed pipeline structure as a support, continue to print other structures; or according to the size of the pump cavity, use a prefabricated stainless steel pipe as an embedded support when 3D metal printing the pump cavity.

[0020] Preferably: In S3, when printing the cavity, it is printed in multiple symmetric or asymmetric parts respectively; the two parts are divided according to the requirements of the cooling water and nitrogen pipelines, sealing and installation in the cavity; rubber sealing ring grooves for assembly are left on the docking surfaces of the multiple parts.

[0021] Preferably, in S4, if a hollow rotor is printed, the hollow part of the hollow rotor includes the inside of the rotating shaft and the rotor blades, and several ribbed stiffeners are included in the hollow part to increase the rotor's ability to resist axial bending.

[0022] Preferably, in S4, the rotor is divided into an inner metal layer and an outer metal layer. The outer layer metal should be selected as a metal material with high temperature resistance, corrosion resistance, friction resistance, and not easily contaminated by dust. When printing, the thickness of the outer layer technology should also leave a margin for the final calibration milling, grinding, and polishing.

[0023] Preferably, in the dry pump manufacturing process, the preparation material of the pump cavity includes ductile iron powder. The preparation material of the rotor can use a single titanium alloy or a single nickel alloy to reduce the weight of the rotor while ensuring physical properties, or use a mixture of multiple materials including ductile iron powder, stainless steel as the inner layer, and titanium and nickel as the outer layer, which can reduce the processing cost while meeting the performance requirements of high temperature resistance, corrosion resistance, friction resistance, and not easily contaminated.

[0024] Preferably, S1 specifically includes the following steps:

[0025] S11: Analyze the working principle and performance requirements of the dry pump, and determine the geometric shape and size of the dry pump rotor and cavity;

[0026] S12: Use software for 3D modeling, and optimize the design considering material properties, manufacturing processes, and other factors;

[0027] S13: Conduct simulation and verification on the design results to verify whether the design meets the expected performance requirements.

[0028] Preferably, S3 specifically includes the following steps:

[0029] S31: Import the designed cavity model into the control system of the metal 3D printer;

[0030] S32: Set the printing parameters, including printing layer thickness, printing speed, and filling density;

[0031] S33: Conduct metal 3D printing.

[0032] Preferably, S5 specifically includes the following steps:

[0033] S51: Fix the dry pump cavity and rotor completed by metal 3D printing on a 4-axis or 5-axis machining center;

[0034] S52: Use tools for calibration machining to ensure that the dimensional accuracy and surface quality of the cavity and rotor meet the requirements;

[0035] S53: Conduct surface polishing to improve the smoothness and corrosion resistance of the cavity and rotor.

[0036] The beneficial effects of the present invention are as follows:

[0037] 1. The main idea of the present invention is to break through the technical bottleneck, find a new way, and adopt the 3D metal printing additive manufacturing technology to manufacture the main structural parts such as the cavity and rotor of the dry pump; the printer realizes the one-time forming processing of weight reduction, cooling water pipelines and nitrogen purging pipelines according to the optimized design.

[0038] 2. The present invention realizes the high temperature resistance, corrosion resistance and weight reduction of the rotor through the mixing and combined printing of multiple metals, and reduces the axial bending of the rotor through hollowing and its internal truss; the milling and polishing technologies of a 4-axis or 5-axis precision machining center are adopted to realize the calibration processing and polishing of the inner surface of the pump cavity and the surface of the rotor; the processing of each small part in the dry pump is completed, and finally the dry pump is assembled.

[0039] 3. The technology of the present invention can realize more abundant and complex internal and surface structures of the dry pump parts, so as to meet the requirements for achieving higher performance of the dry pump. Brief Description of the Drawings

[0040] Figure 1 It is a schematic structural view of a long-axis type hollow dry pump rotor in a dry pump manufacturing process based on metal 3D printing technology proposed by the present invention;

[0041] Figure 2 It is a flow chart of a dry pump manufacturing process based on metal 3D printing technology proposed by the present invention. Detailed Embodiments

[0042] The technical solutions of the present invention will be further described in detail below in conjunction with the specific embodiments.

[0043] Embodiment 1:

[0044] A dry pump manufacturing process based on metal 3D printing technology includes the following steps:

[0045] S1: Design the structure of the dry pump rotor and the dry pump cavity;

[0046] S2: Select the metal 3D printing material;

[0047] S3: Through metal 3D printing, print to form the dry pump cavity;

[0048] S4: Through metal 3D printing, print to form a solid or hollow dry pump rotor;

[0049] S5: The inner surface of the dry pump cavity and the outer surface of the rotor completed by metal 3D printing are subjected to final calibration processing and surface polishing on a 4-axis or 5-axis machining center;

[0050] S6: For other small and structurally standardized components such as the sealing kit and buckle of the dry pump, they are directly processed using conventional precision machining techniques.

[0051] S7: Assemble all the above-prepared components into a dry pump and conduct inspections.

[0052] Among them, in S3, when printing the cavity, a spiral cooling water flow pipeline, a hot nitrogen dust purge pipeline with a more complex structure, a larger volume, and more accurate positioning, a more reasonable dust collection cavity, a more reliable overflow valve position with a more reasonable sealing structure, and the installation position of the embedded monitoring sensor and its signal cable pipeline are simultaneously formed; in this way, the weight of the pump body can be significantly reduced.

[0053] Specifically, in step S3, a dust collection cavity is formed at the gas outlet in the dry pump cavity; the dry pump cavity is also equipped with a matching sealing cover.

[0054] By setting the sealing cover and the dust collection cavity, during the maintenance stage of the dry pump, the sealing cover can be opened to remove dust; during processing, the specific shape of the dust collection cavity should make full use of the metal shell thickness and shape of the pump cavity to reduce the external protrusion size; generally, the volume of the dust collection cavity is controlled within 2 - 10 cubic centimeters.

[0055] Among them, in S3, when printing the cavity, it is printed in two symmetric or asymmetric parts respectively; the two parts are divided according to the requirements of the cooling water and nitrogen pipelines, sealing, and installation inside the cavity; a rubber sealing ring groove is left on the docking surface of the two parts for assembly.

[0056] Among them, as Figure 1 shown in the long-axis type rotor, in S4, if the printed rotor is a hollow rotor, the hollow part of the hollow rotor includes the inside of the rotating shaft and the rotor blades, and several rib-shaped reinforcing ribs (trusses) are included in the hollow part to increase the rotor's ability to resist axial bending.

[0057] Among them, in S4, the rotor is generally divided into an inner metal layer and an outer metal layer. Among them, the inner metal layer is made of ductile iron, stainless steel, etc., and the metal material of the outer metal layer is made of titanium alloy, nickel alloy, etc. For rotors with very high requirements for high temperature resistance, corrosion resistance, and wear resistance, the rotor can be entirely printed with titanium alloy or nickel alloy. When printing the rotor, a margin should be left for the final calibration milling, grinding, and polishing.

[0058] During metal 3D printing, the main material for preparing the pump cavity is ductile iron powder.

[0059] Among them, S1 specifically includes the following steps:

[0060] S11: Analyze the working principle and performance requirements of the dry pump, and determine the geometric shape and size of the dry pump rotor and cavity.

[0061] S12: Perform 3D modeling using software and optimize the design by considering factors such as material properties and manufacturing processes;

[0062] S13: Conduct simulation and verification on the design results to verify whether the design meets the expected performance requirements.

[0063] Among them, the specific steps of S3 are as follows:

[0064] S31: Import the completed cavity model into the control system of the metal 3D printer;

[0065] S32: Set the printing parameters, including layer thickness, printing speed, filling density, etc.;

[0066] S33: Perform metal 3D printing, and technologies such as layer-by-layer stacking or laser cladding can be adopted as needed.

[0067] Among them, the specific steps of S5 are as follows:

[0068] S51: Fix the dry pump cavity and rotor completed by metal 3D printing on a 4-axis or 5-axis machining center;

[0069] S52: Use tools for calibration machining to ensure that the dimensional accuracy and surface quality of the cavity and rotor meet the requirements;

[0070] S53: Conduct surface polishing to improve the smoothness and corrosion resistance of the cavity and rotor.

[0071] As mentioned above, it is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A manufacturing process for a dry pump based on metal 3D printing technology, characterized in that, It includes the following steps: S1: Design the structure of the dry pump rotor and the dry pump cavity; S2: Select metal 3D printing materials; S3: Through metal 3D printing, print to form the dry pump cavity; S4: Through metal 3D printing, print to form a solid or hollow dry pump rotor; S5: The inner surface of the dry pump cavity and the outer surface of the rotor completed by metal 3D printing are subjected to final calibration machining and surface polishing on a machining center; S6: The sealing kits, buckles, and other standard components of the dry pump are directly processed or purchased using conventional precision machining techniques; S7: Assemble all the above components into a dry pump and conduct inspections.

2. The manufacturing process of a dry pump based on metal 3D printing technology according to claim 1, characterized in that, In S3, when printing the cavity, a spiral or folded-back cooling water flow pipeline, a hot nitrogen dust purge pipeline, a dust collection chamber, the position of the pressure relief valve, and the installation position of the embedded monitoring sensor and its signal cable pipeline are formed inside the cavity; The dust collection chamber is arranged at the air outlet of the dry pump cavity, and the dry pump cavity is also equipped with a matching sealing cover.

3. The manufacturing process of a dry pump based on metal 3D printing technology according to claim 2, characterized in that, In the dry pump manufacturing process, after forming a spiral or folded-back cooling water flow pipeline and a hot nitrogen dust purge pipeline, using the formed pipeline structure as a support, continue to print other structures; or according to the size of the pump cavity, use prefabricated stainless steel pipes as embedded supports when 3D metal printing the pump cavity.

4. A dry pump manufacturing process based on metal 3D printing technology according to claim 2, characterized in that, In S3, when printing the cavity, it is printed in multiple symmetric or asymmetric parts respectively; the two parts are divided according to the requirements of the cooling water and nitrogen pipelines, sealing, and installation inside the cavity; rubber sealing ring grooves are left on the docking surfaces of the multiple parts during assembly.

5. A dry pump manufacturing process based on metal 3D printing technology according to claim 1, characterized in that, In S4, if a hollow rotor is printed, the hollow part of the hollow rotor includes the inside of the rotating shaft and the rotor blades, and several rib-shaped reinforcing ribs are included in the hollow part to increase the rotor's ability to resist axial bending.

6. A dry pump manufacturing process based on metal 3D printing technology according to claim 5, characterized in that, In S4, the rotor is divided into an inner metal layer and an outer metal layer. The outer layer metal should be selected as a metal material with high temperature resistance, corrosion resistance, wear resistance, and not easily contaminated by dust. When printing, the thickness of the outer layer technology should also leave a margin for the final calibration milling, grinding, and polishing.

7. A dry pump manufacturing process based on metal 3D printing technology according to any one of claims 1-6, characterized in that, In the dry pump manufacturing process, the preparation material of the pump cavity includes ductile iron powder. The preparation material of the rotor uses a single titanium alloy or a single nickel alloy to reduce the weight of the rotor while ensuring physical properties, or uses a mixture of multiple materials including ductile iron powder, stainless steel as the inner layer, and titanium and nickel as the outer layer to reduce processing costs while meeting the performance requirements of high temperature resistance, corrosion resistance, wear resistance, and not easily contaminated.

8. A manufacturing process for a dry pump based on metal 3D printing technology according to claim 1, characterized in that, S1 specifically includes the following steps: S11: Analyze the working principle and performance requirements of the dry pump, and determine the geometric shape and size of the dry pump rotor and cavity; S12: Use software for 3D modeling and optimize the design considering material characteristics, manufacturing processes, etc.; S13: Conduct simulation and verification on the design results to verify whether the design meets the expected performance requirements.

9. A dry pump manufacturing process based on metal 3D printing technology according to claim 1, characterized in that, S3 specifically includes the following steps: S31: Import the designed cavity model into the control system of the metal 3D printer; S32: Set printing parameters, including printing layer thickness, printing speed, and filling density; S33: Conduct metal 3D printing.

10. A dry pump manufacturing process based on metal 3D printing technology according to claim 1, characterized in that, S5 specifically includes the following steps: S51: Fix the dry pump cavity and rotor completed by metal 3D printing on the machining center; S52: Use tools for calibration machining to ensure that the dimensional accuracy and surface quality of the cavity and rotor meet the requirements; S53: Conduct surface polishing to improve the smoothness and corrosion resistance of the cavity and rotor.

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