Turbo molecular vacuum pump and method for manufacturing rotor

Abstract

The invention relates to a turbo molecular vacuum pump (1) comprising a stator (2) and a rotor (3) designed to rotate in said stator (2), said rotor (3) comprising a hub (9) and at least one blade stage (10a-10 h) comprising blades (11a, 11b) regularly distributed around the periphery of said hub (9), characterized in that the blades (11a) of at least one blade stage (10a) of said rotor (3) are hollow.

Description

Technical Field

[0001] The present invention relates to a turbomolecular vacuum pump and also to a method for manufacturing a rotor of a turbomolecular vacuum pump. Background Art

[0002] Producing a high vacuum within the enclosure requires the use of a turbomolecular vacuum pump, which includes a stator in which a rotor is driven to rotate rapidly, for example at speeds in excess of 30,000 revolutions per minute.

[0003] In some applications of such vacuum pumps, particularly in the semiconductor manufacturing industry, there is a constant effort to increase pumping rates - which results in larger and larger pumps - and to increase the operating temperature of the vacuum pumps to avoid deposition of reaction byproducts in the pumps, thereby ensuring proper service life and increasing productivity of production equipment.

[0004] However, the increase in the size of the vacuum pump may bring about problems related to the supply of raw materials.

[0005] Large vacuum pumps also take up too much space, making them difficult to install beneath the process chamber—where there are often already many of the accessories needed to operate the equipment.

[0006] Some processes, especially in the semiconductor manufacturing industry, are using new, more complex chemical reactions that generate more and more byproducts that are deposited in the vacuum pump if it is not heated sufficiently. Turbomolecular vacuum pumps that were set at 50°C to 60°C decades ago now need to be set at around 150°C.

[0007] The rotors of modern turbomolecular vacuum pumps are usually made of high-performance aluminum alloys, which have by far the best creep resistance. This solution offers a good compromise between the vacuum performance achieved in terms of the rotational speed of the pump and the kinetic energy inertia stored in the pump. In fact, if the rotor is damaged, all the dynamic rotational energy of the rotor can be contained in the vacuum pump housing to ensure the safety of people and property. However, under stress, turbomolecular vacuum pumps must not exceed a certain heating temperature, in particular 150°C, otherwise there is a risk of creep in the rotor. The rotor is also difficult to cool, because it is usually located on magnetic bearings and is therefore not in contact with the stator. Summary of the invention

[0008] One of the objects of the present invention is to provide a turbomolecular vacuum pump which at least partially overcomes the disadvantages of the prior art, in particular by enabling the kinetic energy stored in the vacuum pump to be reduced. Another object of the present invention is to increase the pumping rate and / or the operating temperature of the turbomolecular vacuum pump without increasing the volume of the vacuum pump.

[0009] To this end, the invention relates to a turbomolecular vacuum pump comprising a stator and a rotor designed to rotate in the stator, the rotor comprising a hub and at least one blade stage comprising blades regularly distributed around the circumference of the hub, characterized in that the blades of at least one blade stage of the rotor are hollow.

[0010] Only the outer surface of the rotor needs to pump gas, so a partially hollow rotor does not affect the pumping performance. On the other hand, the hollow blades reduce the weight of the rotor, which allows to reduce the kinetic energy stored in the vacuum pump, so that the rotor can be contained in the housing of the vacuum pump in the event of an explosion. This allows the rotor to be made at least partially of an alloy that is denser than aluminum alloy, thus providing better creep resistance.

[0011] The vacuum pump may also have one or more of the features described below, which may be applied individually or in combination.

[0012] The rotor has, for example, four or more blade stages, and the first blade stage located on the suction port side of the vacuum pump has hollow blades.

[0013] The skin thickness of the hollow blade is, for example, equal to or less than 3 mm and / or equal to or greater than 0.2 mm.

[0014] The diameter of the rotor is, for example, equal to or greater than 160 mm and / or equal to or less than 450 mm.

[0015] The rotor may have a cylindrical skirt downstream of at least one blade stage, the cylindrical skirt being hollow.

[0016] The hollow cylindrical skirt may have an internal reinforcement element connecting the mutually facing walls within the cavity of the cylindrical skirt.

[0017] The hub may also be hollow.

[0018] The rotor may be at least partially made of a material having a density greater than that of aluminum alloy (i.e., a density greater than 2.7 g / cm 3 ) alloy.

[0019] The rotor is, for example, at least partially made of stainless steel or a titanium alloy or a nickel-based alloy.

[0020] The density of these alloys is greater than that of aluminum alloys. The weight of these alloys is about two to three times that of aluminum alloys. The high density of these alloys provides excellent mechanical strength and better high temperature creep resistance than aluminum alloys. These alloys also have good corrosion and oxidation resistance.

[0021] These materials, for example, allow turbomolecular vacuum pumps to be heated to higher temperatures without risk of creep. These materials also allow the gas flow rate of a turbomolecular vacuum pump to be increased without risk of rotor creep. These materials may also allow the rotor to rotate faster than in prior art vacuum pumps of the same size, thereby increasing the pumping rate without risk of rotor creep. The use of these materials may also allow the size of the vacuum pump to be reduced while the rotor rotates at a higher speed, thus having the same pumping performance without risk of rotor creep.

[0022] These alloys are more expensive and heavier than aluminum alloys, but a rotor with at least one blade stage with hollow blades reduces the weight of the rotor, which reduces the kinetic energy when the rotor explodes, and reduces the raw materials used, thereby reducing raw material costs and helping to alleviate potential supply issues.

[0023] At least one blade stage of the rotor with hollow blades can be made by metal additive manufacturing. Stainless steel, titanium alloys and nickel-based alloys are particularly suitable for metal additive manufacturing, in particular metal additive manufacturing by laser melting.

[0024] The radial ends of the hollow blades produced by metal additive manufacturing are, for example, open (open).

[0025] The hollow cylindrical skirt can also be made by metal additive manufacturing. The annular end of the skirt made by metal additive manufacturing is, for example, open.

[0026] The rotor may be manufactured in one piece.

[0027] The rotor may be manufactured by interference fitting at least one blade stage having hollow blades made by metal additive manufacturing onto the hub.

[0028] The rotor may be manufactured by additive manufacturing at least one blade-level metal having hollow blades onto the hub.

[0029] The present invention also relates to a method for manufacturing a rotor of a turbomolecular vacuum pump as described above, wherein the rotor is completely manufactured by metal additive manufacturing.

[0030] The invention also relates to a method for manufacturing a rotor of a turbomolecular vacuum pump as described above, wherein at least one blade stage with hollow blades is manufactured by metal additive manufacturing and is interference-fitted onto the hub.

[0031] A hollow cylindrical (cylindrical) skirt can also be made by metal additive manufacturing and interference fit onto the hub.

[0032] The invention also relates to a method for manufacturing a rotor of a turbomolecular vacuum pump as described above, wherein at least one blade stage with hollow blades is manufactured on the hub by metal additive manufacturing.

[0033] The hollow cylindrical skirt can also be made on the hub by metal additive manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Other advantages and features are contained in the description of non-limiting specific embodiments of the invention and in the accompanying drawings, in which:

[0035] [ Figure 1 ] Figure 1 is an axial cross-sectional view of the turbomolecular vacuum pump according to the first embodiment.

[0036] [ Figure 2A ] Figure 2A yes Figure 1 A perspective view of the rotor of a vacuum pump.

[0037] [ Figure 2B ] Figure 2B yes Figure 2A Detailed view of the rotor in Figure 1.

[0038] [ Figure 3 ] Figure 3 yes Figure 2A Cross-sectional view of the rotor in .

[0039] [ Figure 4 ] Figure 4 is a cross-sectional view of a turbomolecular vacuum pump rotor according to a second embodiment.

[0040] [ Figure 5 ] Figure 5 is a cross-sectional view of a turbomolecular vacuum pump rotor according to a third embodiment.

[0041] [ Figure 6 ] Figure 6 is a cross-sectional view of a turbomolecular vacuum pump rotor according to a fourth embodiment.

[0042] [ Figure 7 ] Figure 7 is a cross-sectional view of a turbomolecular vacuum pump rotor according to a fifth embodiment.

[0043] In these drawings, the same reference numbers are used to indicate the same elements. DETAILED DESCRIPTION

[0044] The following embodiments are examples. Although the description relates to one or more embodiments, this does not necessarily mean that each reference numeral refers to the same embodiment or that a feature applies to only one embodiment. Individual features of different embodiments may also be combined or exchanged to provide other embodiments.

[0045] "Upstream" refers to an element that is located before another element relative to the flow direction of the pumped gas. Conversely, "downstream" refers to an element that is located after another element relative to the flow direction of the pumped gas.

[0046] The axial direction refers to a direction parallel to the rotation axis II of the vacuum pump rotor, and the radial direction refers to a direction perpendicular to the axial direction.

[0047] Figure 1 A first exemplary embodiment of a turbomolecular vacuum pump 1 is shown.

[0048] The turbomolecular vacuum pump 1 comprises a stator 2 in which a rotor 3 is arranged to rotate in an axial direction at a high speed, for example, at a rotation speed exceeding 20,000 revolutions per minute.

[0049] The pumped gas enters through the suction hole 4 of the turbomolecular vacuum pump 1 and is discharged through the exhaust hole 5. During operation, the exhaust hole 5 is connected to the roughing pump.

[0050] The stator 2 comprises in particular a housing 12, for example assembled from several parts, at least two annular stator stages 6a-6h fastened to the housing 12, and in this case a high-voltage bracket 7, which is fastened to the housing 12 and in which the exhaust opening 5 of the vacuum pump 1 is arranged.

[0051] The stator 2 comprises an annular inlet flange 8 surrounding the suction opening 4 for connecting the vacuum pump 1 to a housing requiring decompression.

[0052] like Figure 2A and 3 As clearly shown in the figure, the rotor 3 has a hub 9 and at least one blade stage 10a-10h. Each blade stage 10a-10h includes blades 11a, 11b, which extend substantially radially from the hub 9 at a certain angle and are evenly distributed on the circumference of the hub 9. Each blade stage 10a-10h has, for example, 20 to 30 blades 11a, 11b, respectively, in this example, 22 blades.

[0053] The rotor 3 has, for example, more than four blade stages 10 a - 10 h , for example, between four and twelve blade stages 10 a - 10 h (eight in the example shown in the figure). The first blade stage 10 a is a blade stage located on the suction port 4 side of the turbomolecular vacuum pump 1 .

[0054] The annular stator stages 6a-6h of the stator 2 are respectively arranged between the consecutive blade stages 10a-10h of the rotor 3. The annular stator stages 6a-6h and the blade stages 10a-10h are axially connected to each other along the rotation axis II of the rotor 3 ( Figure 1 ).

[0055] The rotor 3 may have a cylindrical skirt 13, called a Holvik skirt, downstream of the at least two blade stages 10a-10h, formed by a smooth cylinder, rotating counter to the spiral grooves 14 in the stator 2. The spiral grooves 14 in the stator 2 help compress and guide the pumped gas to the exhaust holes 5.

[0056] The rotor 3 also has an inner bowl 15 below the cylindrical skirt 13, coaxial with the axis of rotation II and arranged opposite the bell 17 of the stator 2, protruding below the rotor 3. In operation, the rotor 3 rotates in the stator 2 without contact between the inner bowl 15 and the bell 17.

[0057] The rotor 3 is fastened to the drive shaft 18 of the vacuum pump 1, for example by means of screws 19 passing through the hub 9 of the rotor 3. The rotor 3 is driven to rotate in the stator 2 by an internal motor 20 of the vacuum pump 1. The motor 20 is arranged, for example, in a bell-shaped part 17 of the stator 2, which is arranged below the inner bowl 15 of the rotor 3, through which the drive shaft 18 passes.

[0058] The rotor 3 is guided laterally and axially by magnetic and / or mechanical bearings 21 located in the stator 2 and supporting the drive shaft 18 of the rotor 3. For example, a first bearing 21 supports and guides a first end of the drive shaft 18 located in the base of the bell 17 of the stator 2, while a second bearing 21 supports and guides a second end of the drive shaft 18 arranged at the top of the bell 17.

[0059] Other electrical or electronic components, such as a position sensor, may be accommodated in the bell-shaped portion 17 of the stator 2 .

[0060] The vacuum pump 1 may include a heating device designed to heat the stator 2. The heating device may include an external resistive heating belt designed to heat the housing 12 of the vacuum pump 1, or a radiation element arranged in the gas flow path of the vacuum pump 1, which is designed, for example, to heat the high-voltage bracket 7 of the stator 2 in which the spiral groove 14 is formed.

[0061] like Figure 3 As shown in the cross-sectional view in FIG. 1 , the blades 11 a of at least one blade stage 10 a of the rotor 3 are hollow.

[0062] The cavity of the hollow blade 11a extends, for example, inside all corresponding blades 11a. All blades 11a of the corresponding blade stage 10a are hollow. The skin thickness e of the hollow blade 11a is ( Figure 2B ) is, for example, equal to or less than 3 mm (maximum thickness over the entire length of the cavity of the blade 11a) and / or equal to or greater than 0.2 mm (minimum thickness over the entire length of the cavity of the blade 11a).

[0063] Only the outer surface of the rotor 3 needs to pump gas, so the partially hollow rotor 3 does not affect the pumping performance. On the other hand, the hollow blades 11a reduce the weight of the rotor 3, which makes it possible to reduce the kinetic energy stored in the vacuum pump 1, so that the rotor 3 can also be contained in the housing 12 of the vacuum pump 1 in the event of an explosion.

[0064] exist Figures 1 to 3 In the first embodiment shown, only the blades 11a in one blade stage 10a of the rotor 3 are hollow, in particular only the first blade stage 10a located on the side of the suction opening 4 has hollow blades 11a. This is the blade stage 10a of the rotor 3 with the largest blades 11a, thus providing the greatest weight and material savings. The blades 11b of the other blade stages 10b-10h are solid.

[0065] However, the blade stage with hollow blades 11 a may be another stage of the rotor 3 .

[0066] Furthermore, the rotor 3 may be at least partially made of a material having a density greater than that of aluminum alloy, i.e. greater than 2.7 g / cm 3 Made of alloy.

[0067] The rotor 3 is, for example, at least partially made of stainless steel or a titanium alloy or a nickel-based alloy (also called a superalloy), such as 600(NiCr15Fe), 625(NiCr22Mo9Nb) or 718(NiCr19Fe19Nb5Mo3). The minor alloying metals in quartz are mainly niobium, manganese and molybdenum.

[0068] The density of these alloys is greater than that of aluminum alloys. The weight of these alloys is about two to three times that of aluminum alloys. The high density of these alloys provides excellent mechanical strength and better high temperature creep resistance than aluminum alloys. These alloys also have good corrosion and oxidation resistance.

[0069] These materials enable, for example, the turbomolecular vacuum pump 1 to be heated to higher temperatures without the risk of creep. For example, the heating device can be configured to heat the stator 2 to a temperature equal to or greater than 150° C., for example 200° C., thereby preventing the formation of reaction product deposits in the vacuum pump 1, particularly in semiconductor manufacturing applications.

[0070] These materials also allow the gas flow rate of the turbomolecular vacuum pump 1 to be increased without the rotor 3 running the risk of creeping.

[0071] These materials also allow the rotor 3 to rotate faster than the vacuum pump 1 of the same size in the prior art, thereby increasing the pumping rate without the risk of creep of the rotor 3. The rotation speed of the rotor 3 is, for example, equal to or greater than 20,000 rpm. The diameter D of the rotor 3 (in which the radial ends of the blades 11a, 11b are inscribed) is, for example, equal to or greater than 160 mm and / or equal to or less than 450 mm ( Figure 3 ).

[0072] The use of these materials also makes it possible to reduce the size of the vacuum pump 1 while allowing a higher rotation speed of the rotor 3 and thus the same pumping performance without the risk of creep of the rotor 3 .

[0073] These alloys are more expensive and heavier than aluminum alloys, but a rotor 3 having at least one blade stage 10a including hollow blades 11a reduces the weight of the rotor 3, which reduces the kinetic energy of the rotor 3 when it explodes, and reduces the raw materials used, thereby reducing raw material costs and helping to alleviate potential supply issues.

[0074] The rotor 3 is produced, for example, in one piece.

[0075] All or part of the rotor 3 may be made of a constituent metal such as stainless steel, a titanium alloy or a nickel alloy by metal additive manufacturing, for example by laser melting or electron beam melting.

[0076] In a laser melting process, such as the direct energy deposition (DED) process - also known as direct metal deposition (DMD), the constituent metals in the form of metal powders are deposited and then melted by the laser beam and fused with the previous layer.

[0077] In an electron beam melting process, such as electron beam additive manufacturing (EBAM), an electron beam melts the constituent metals in the form of thick wires for 3D printing.

[0078] Stainless steels, titanium alloys and nickel-based alloys are particularly suitable for metal additive manufacturing, especially metal additive manufacturing via laser melting.

[0079] At least one blade stage 10a of the rotor 3 comprising hollow blades 11a is produced by metal additive manufacturing.

[0080] In a first embodiment in which the rotor 3 is produced in one piece, the rotor 3 may be produced completely by metal additive manufacturing.

[0081] The radial ends of the hollow blades 11a made by metal additive manufacturing, in this case the blades in the first blade stage 10a, may be open ( Figure 2B ), which is easier to manufacture.

[0082] The rotor 3 may also be coated after manufacture, in particular to improve corrosion resistance. For example, the rotor has a nickel coating.

[0083] Although only one blade stage 10 a has the hollow blades 11 a in the first embodiment, the turbomolecular vacuum pump 1 may have a plurality of blade stages including hollow blades.

[0084] For example, the turbomolecular vacuum pump 1 has two blade stages comprising hollow blades. These stages are not necessarily continuous in the gas pumping path. For example, Figure 4 As shown, the first blade stage 10a and the sixth blade stage 10f located on the suction port 4 side have hollow blades 11a.

[0085] The turbomolecular vacuum pump 1 may also have more than two blade stages including hollow blades. Figure 5 As shown, the first, third and sixth blade stages 10a, 10c, 10f have hollow blades 11a.

[0086] Likewise, all blades 11a of all blade stages 10a-10h of the rotor 3 may also be hollow ( Figure 7 ).

[0087] Blade stages made with metal additive manufacturing, Figure 4 The first and sixth blade stages 10a, 10f or Figure 5 The first, third and sixth blade stages 10a, 10c, 10f or Figure 7 The ends of the blades 11a of all blade stages 10a-10h may be open.

[0088] Figure 6 Another exemplary embodiment is shown.

[0089] In this example, the rotor 3 is assembled from a plurality of parts, firstly a hub 9, which in this example is made integrally with a cylindrical skirt 13 and blade stages having solid blades 11b (in this example the second, fourth, fifth, seventh and eighth stages 10b, 10d, 10e, 10g and 10h), and secondly at least one blade stage comprising hollow blades 11a (in this example the first, third and sixth blade stages 10a, 10c, 10f).

[0090] The different parts may be made of the same material or of different materials.

[0091] During manufacture of the rotor 3, the hub 9 and in this case the cylindrical skirt 13 and the blade stages 10b, 10d, 10e, 10g and 10h comprising solid blades 11b may be manufactured in a conventional manner, for example by turning.

[0092] According to a first variant of the multi-component assembly, the rotor 3 is made by interference fitting at least one blade stage (in this case the first, third and sixth blade stages 10a, 10c, 10f) comprising hollow blades 11a onto the hub 9, these blade stages 10a, 10c, 10f being made by metal additive manufacturing.

[0093] According to a second variant of the multi-component assembly, the rotor 3 is made by metal additive manufacturing of at least one blade stage comprising hollow blades 11a on the hub 9. In other words, at least one blade stage comprising hollow blades 11a, in this case the first, third and sixth blade stages 10a, 10c, 10f, is added to the hub 9 by metal additive manufacturing.

[0094] In both variants, the ends of the hollow blades 11a made by metal additive manufacturing, in this case the ends of the blades of the first, third and sixth blade stages 10a, 10c, 10f, may be open.

[0095] Figures 4 to 6 Other features of the example embodiment in are similar to those of the first example embodiment described.

[0096] exist Figure 7 In the exemplary embodiment shown, all blade stages 10a - 10h have hollow blades 11a .

[0097] In this embodiment, the cylindrical skirt 13 is also hollow.

[0098] The hollow cylindrical skirt 13 may have an internal reinforcement element 22 connecting the walls facing each other within the cavity of the cylindrical skirt 13 to increase its mechanical strength.

[0099] In this embodiment, the hub 9 is also hollow.

[0100] Other arrangements are possible, for example some blade stages may have solid blades 11b, or the cylindrical skirt 13 or the hub 9 may be solid.

[0101] During the manufacture of the rotor 3 , the hub 9 may be manufactured using conventional methods or by additive manufacturing.

[0102] The rotor 3 may be manufactured by interference fitting at least one blade stage comprising hollow blades 11 a manufactured by metal additive manufacturing—in this case all blade stages 10 a - 10 h —on the hub 9 and / or by interference fitting the hollow cylindrical skirt 13 onto the hub 9 .

[0103] The rotor 3 can also be manufactured in such a way that metal additive manufacturing of at least one blade stage 10a-10h (in this case all blade stages 10a-10h) including hollow blades 11a and / or the hollow cylindrical skirt 13 is performed on the hub 9. In other words, at least one blade stage 10a-10h including hollow blades 11a and / or the cylindrical skirt 13 is added to the hub 9 by metal additive manufacturing.

[0104] It is also possible to interference fit at least one blade stage 10 a - 10 h comprising a hollow blade 11 a made by metal additive manufacturing on the hub 9 and to add a hollow skirt to the hub 9 by performing metal additive manufacturing on the hub 9 .

[0105] In all variants, the ends of the hollow blades 11a and the cylindrical skirt 13 made by metal additive manufacturing may be open.

Claims

1. A turbomolecular vacuum pump (1), comprising a stator (2) and a rotor (3) designed to rotate in the stator (2), the rotor (3) comprising a hub (9) and at least one blade stage (10a-10h), the blade stage comprising blades (11a, 11b) regularly distributed around the circumference of the hub (9), characterized in that: The blades (11a) of at least one blade stage (10a) of the rotor (3) are hollow.

2. The turbomolecular vacuum pump (1) according to claim 1, characterized in that: The rotor (3) has more than four blade stages (10a-10h), and the first blade stage (10a) located on the suction port (4) side of the vacuum pump (1) has hollow blades (11a).

3. The turbomolecular vacuum pump (1) according to any one of the preceding claims, characterized in that The surface thickness (e) of the hollow blade (11a) is equal to or less than 3 mm and / or equal to or greater than 0.2 mm.

4. The turbomolecular vacuum pump (1) according to any one of the preceding claims, characterized in that The diameter (D) of the rotor (3) is equal to or greater than 160 mm and / or equal to or less than 450 mm.

5. The turbomolecular vacuum pump (1) according to any one of the preceding claims, characterized in that The rotor (3) has a cylindrical skirt (13) located downstream of the at least one blade stage (10a), the cylindrical skirt (13) being hollow.

6. Turbomolecular vacuum pump (1) according to the preceding claim, characterized in that The hollow cylindrical skirt (13) has an internal reinforcing element (22) connecting the facing walls within the cavity of the cylindrical skirt (13).

7. The turbomolecular vacuum pump (1) according to any one of the preceding claims, characterized in that The hub (9) is also hollow.

8. The turbomolecular vacuum pump (1) according to any one of the preceding claims, characterized in that The rotor (3) is at least partially made of stainless steel or titanium alloy or nickel-based alloy.

9. The turbomolecular vacuum pump (1) according to any one of the preceding claims, characterized in that The at least one blade stage (10a) of the rotor (3) comprising hollow blades (11a) is manufactured by metal additive manufacturing.

10. Turbomolecular vacuum pump (1) according to the preceding claim, characterized in that The radial ends of the hollow blades (11a) manufactured by metal additive manufacturing are open.

11. The turbomolecular vacuum pump (1) according to any one of the preceding claims, characterized in that The rotor (3) is manufactured as a single piece.

12. The turbomolecular vacuum pump (1) according to any one of claims 9 or 10, characterized in that The rotor (3) is manufactured by interference fitting at least one blade stage (10a) comprising hollow blades (11a) manufactured by metal additive manufacturing onto the hub (9).

13. The turbomolecular vacuum pump (1) according to any one of claims 9 or 10, characterized in that The rotor (3) is manufactured by metal additive manufacturing of at least one blade stage (10a) including hollow blades (11a) on a hub (9).

14. A method for manufacturing a rotor (3) for a turbomolecular vacuum pump (1) according to claim 11, wherein: The rotor (3) is completely manufactured by metal additive manufacturing.

15. A method for manufacturing a rotor for a turbomolecular vacuum pump (1) according to claim 12, wherein: At least one blade stage (10a) comprising hollow blades (11a) is made by metal additive manufacturing and is interference fit onto the hub (9).

16. A method for manufacturing a rotor (3) for a turbomolecular vacuum pump (1) according to claim 13, wherein: The at least one blade stage (10a) comprising hollow blades (11a) is manufactured on the hub (9) by metal additive manufacturing.

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