Enhanced Vacuum System Components

Abstract

The present invention provides a rotor assembly for a vacuum pump, the rotor assembly including a hub and one or more blade arrangements, each blade arrangement including at least one blade, each blade extending from a blade root adjacent the hub to a blade tip, each blade including a continuous fiber reinforced matrix material. The present invention also provides methods for designing and manufacturing the blades, and vacuum systems having components including a continuous fiber reinforced matrix material. [Selected figure] Figure 3

Description

[Technical field]

[0001] The present invention relates to a rotor assembly for a vacuum system, particularly a vacuum pump, in which one or more components comprise a continuous fibre reinforced matrix material. The present invention further relates to rotor blades and methods of manufacturing the vacuum system and components thereof. [Background technology]

[0002] Typically, turbomolecular pumps include a rotor having an annular array of a plurality of axially spaced, inclined rotor blades. The blades are regularly spaced within each array and extend radially outward from a central shaft. A stator for the pump surrounds the rotor and includes an annular array of inclined stator vanes that axially alternate with the arrays of rotor blades. Each adjacent pair of rotor and stator vane arrays forms a stage of the turbomolecular pump. As the rotor rotates, the blades impinge on the incoming gas molecules, transferring the mechanical energy of the blades to momentum of the gas molecules from the pump inlet, through the stages, to the pump outlet.

[0003] Typically, the rotor of a turbomolecular pump is manufactured as a unitary metal structure, such as a titanium alloy, with the blades integral with the shaft.

[0004] However, there is still a need to increase rotor speeds to reduce running costs across all types of vacuum pumps.

[0005] To date, inherent limitations associated with typical additive manufacturing processes have limited their applicability to vacuum pumps, particularly the strength and durability of the resulting parts.

[0006] For example, Fused Filament Fabrication (FFF) results in parts that exhibit low strength, while prepreg composite construction methods that use a sheet-based approach to form 3D parts are time consuming, difficult to handle, and expensive. Furthermore, bending such sheets around curves can result in overlapping, crumbling, and / or deformation of the fibers, creating undesirable soft spots in the resulting vacuum parts. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2007 / 015056 [Patent Document 2] International Publication No. 2008 / 129317 [Patent Document 3] International Publication No. 2007 / 068973 [Patent Document 4] International Publication No. 2008 / 035112 Summary of the Invention [Problem to be solved by the invention]

[0008] Thus, there is an ongoing need for new components and manufacturing methods that reduce costs and increase operating speeds.

[0009] The present invention seeks to address, at least to some extent, these and other problems in the prior art. [Means for solving the problem]

[0010] The present invention therefore provides in a first aspect a rotor assembly for a vacuum pump comprising a hub and one or more blade arrangements, each blade arrangement including at least one blade extending from a blade root adjacent the hub to a blade tip, the blade comprising a continuous fibre reinforced matrix material and continuous fibres extending from the blade to a portion of the hub immediately adjacent the blade.

[0011] Rotor assemblies in accordance with the present invention can be lighter, faster, and less expensive than known rotor assemblies, and in some cases reduce or eliminate the need for notches, cavities, and other weight reduction strategies.

[0012] Typically, a rotor assembly includes a plurality of blade arrays. A blade array may include one or more, typically two or more, blades. When an assembly includes a plurality of arrays and / or an array includes a plurality of blades, typically every blade includes continuous fibers extending from that blade to the portion of the hub immediately adjacent to that blade.

[0013] The hub may be substantially annular with the blades extending radially therefrom.

[0014] The hub may be formed integrally with the rotor shaft of the vacuum pump, or a series of rotor assemblies may be arranged in sequence with adjacent hubs bonded together to form the rotor shaft.

[0015] In an embodiment, the continuous fibers may extend from the blades to the rotor shaft.

[0016] The type and / or lay-up of the reinforcing continuous fibers is preferably varied between the blade root and the blade tip. Typically, the type and / or lay-up of the continuous fibers is different at the blade root than at the blade tip.

[0017] The rotor assembly may be for a turbomolecular pump and includes an annular hub and one or more substantially annular blade arrays, each blade array including a plurality of substantially identical blades extending radially from a blade root adjacent the hub to a blade tip, each blade including a continuous fiber reinforced matrix material and continuous fibers extending from the blade to a portion of the hub immediately adjacent the blade.

[0018] The rotor assembly may be a Roots-type rotor assembly. A Roots-type rotor assembly may include multiple rotor arrangements in the form of a series of stages. Typically, each Roots-type rotor stage includes two to five blades, also called lobes, extending radially from the blade root adjacent the hub to the blade tip. The hub may be separate from the rotor shaft or may be integrally formed therewith. Alternatively, the hubs of adjacent stages may be joined to form the rotor shaft. Each blade includes a continuous fiber reinforced matrix material and continuous fibers extending from the blade (or lobe) to the portion of the hub immediately adjacent the blade. WO2007015056 discloses a Roots-type vacuum rotor assembly suitable for employing the present invention, which is incorporated herein by reference.

[0019] The rotor assembly may be a nosey (or claw) type rotor assembly. A nosey type rotor assembly may include multiple rotor arrangements in the form of a series of stages. Typically, each nosey type rotor stage includes a single blade, also called a claw, that extends radially from the blade (or claw) root in contact with the hub to the blade (or claw) tip. The hub may be separate from the rotor shaft or may be integrally formed therewith. Alternatively, the hubs of adjacent stages may be joined to form the rotor shaft. Each blade includes a continuous fiber reinforced matrix material and continuous fibers extending from the blade (claw) to a portion of the hub directly adjacent the blade. WO2008129317 discloses a nosey type vacuum rotor assembly suitable for employing the present invention and is incorporated herein by reference.

[0020] A rotor assembly according to the present invention may include both one or more Nosey-type rotor arrangements, and one or more Roots-type rotor arrangements.

[0021] Alternatively, the rotor assembly may be a rotor assembly for a screw pump. The rotor assembly includes an arrangement of externally threaded blades in the form of a series of stages. Typically, each screw pump rotor stage includes a single blade extending from a hub. The rotor may be tapered. Typically, the pitch of the threads may increase gradually from the fluid inlet to the fluid outlet of the pump. The hub may be separate from the rotor shaft or may be integrally formed therewith. Alternatively, the hubs of adjacent stages may be connected to form the rotor shaft. Each blade includes a continuous fiber reinforced matrix material and continuous fibers extending from the blade to a portion of the hub directly adjacent the blade. WO2007068973 discloses a screw pump rotor assembly suitable for employing the present invention and is incorporated herein by reference.

[0022] Alternatively, the rotor assembly may be for a drag pump, such as a Siegbahn type pump mechanism. Each rotor may include planar, disk-shaped blades extending outwardly from a hub in the form of a drive shaft. Each blade includes a continuous fiber reinforced matrix material and continuous fibers extending from the blade to a portion of the hub immediately adjacent the blade. WO2008035112 discloses a Siegbahn type rotor assembly suitable for employing the present invention, and is incorporated herein by reference.

[0023] In an embodiment, the blade root and / or blade tip have higher tensile strength and / or bending strength and / or creep resistance and / or elastic strain control than the remainder of the blade body.

[0024] Additionally or alternatively, the hub and blades may each include a substantially similar or identical matrix material, with each blade including continuous fibers extending from the blade to the portion of the hub immediately adjacent the blade.

[0025] Preferably, the continuous fiber reinforced matrix material comprises a molten filament matrix. Preferably, the continuous fiber reinforced matrix material comprises a molten composite filament and a molten filament matrix. Preferably, the composite filament and the matrix filament are printed. For the avoidance of doubt, the composite filament and / or the molten filament may be as described elsewhere in this application.

[0026] In an embodiment of the invention, each blade may include a lattice core, typically an additively manufactured lattice core, preferably a 3D printed lattice core.

[0027] The present invention further includes drag pumps, turbomolecular pumps, screw pumps, and mechanical pumps including Roots and / or Nosey rotor arrangements.

[0028] The invention provides in a further aspect a method of manufacturing vacuum pump rotor blade assemblies, each rotor blade assembly including at least one blade extending from a blade root adjacent a hub to a blade tip, the blade including a continuous fiber reinforced matrix material, the method including melting continuous composite filaments and matrix filaments to form the blades, the at least one continuous reinforcing fiber of each blade being positioned to extend from the blade to a portion of the hub immediately adjacent the blade root. The rotor assembly so manufactured may be in accordance with the previous aspect.

[0029] In another aspect, the invention provides a vacuum system including a unitary component comprising a continuous fiber reinforced matrix material, where the type and / or layup of the continuous reinforcing fibers in a first portion of the component is different from that in a second portion of the component, typically the layup and / or type of the continuous reinforcing fibers is such that at least one mechanical property of the first portion is different from a mechanical property of the second portion.

[0030] The part may further comprise a third portion, the type and / or layup of the reinforcing continuous fibers of which differs from the second and first portions of the same part, such that at least one mechanical property of the third portion of the respective part is preferably different from the mechanical property of either the first or second portion of the same part.

[0031] In use, the part may be a moving part, such as a moving blade in a vacuum system. Typically, the part is additively manufactured.

[0032] Typically, each of the individual portions (e.g., the first portion and / or the second portion and / or the third portion) comprises a single continuous fiber. The individual portions may be defined by different portions of the component reinforced by a single continuous fiber. Alternatively, a single component may comprise a single continuous fiber. Thus, in an embodiment, a continuous fiber may reinforce the first portion, the second portion and any third portion.

[0033] Continuous fibres are distinct from chopped fibres, which typically have a length of 0.2mm to 10mm. Typically, the continuous fibres in a part according to the invention have a length of at least 0.5m, preferably from about 1m to about 50m. The exact length depends on the size of the part and the particular lay-up of the continuous fibres in the part. Typically, the continuous fibres have a width and / or diameter of from about 0.5mm to about 1.2mm, preferably from about 0.8mm to about 1mm. If the fibre is a composite filament, the radius of the fibre can be increased, for example by surrounding the reinforcing continuous fibres in a plastic shell with a pre-wetting material. Thus, the composite filament can have a radius of from about 0.5mm to about 1.5mm, preferably about 1mm or more.

[0034] It may be desirable to include a cutting mechanism in any three-dimensional printing system used to manufacture this part. Such a cutting mechanism may be used to provide selective termination to deposit a desired length of material. Otherwise, in use, the printing process may not be easily terminated due to the deposited material still being connected to the material in the deposition head, such as a continuous core.

[0035] The first portion can be located at and / or directly adjacent to an edge of the part, for example extending along a peripheral edge of the part, or at an intersection of a first surface and a second surface of the same part. When located at the intersection, the first portion can cross the intersection.

[0036] The second portion can be located at another edge and / or another intersection of the same part, or the second portion can be a body portion of the part that extends between an edge, such as a peripheral edge, and an intersection.

[0037] Typically the part is a moving part and during use the first portion is a relatively high stress part of the part, the second portion is a relatively low stress part of the part and the third portion may be a relatively medium stress part of the same part or a relatively higher or lower stress part of the same part.

[0038] In an embodiment, the first portion is disposed at a peripheral edge of the component.

[0039] The first and second portions can be contiguous or separate. Similarly, the third portion can be contiguous with either the first and / or second portion or separate from either the first and / or second portion.

[0040] The type of reinforcing fibres in the present invention may refer to the geometric shape of the fibres, e.g. the cross-sectional shape and / or size of the fibres. Additionally or alternatively, the type of reinforcing fibres may also refer to the material from which the fibres are formed, e.g. polymer fibres, carbon fibres, metal fibres or glass fibres. Thus, an individual part may have a first part comprising continuous fibres comprising a first material, a second part comprising continuous fibres comprising a second material and optionally a third part comprising continuous fibres comprising a third material, the first, second and third materials being respectively different from each other.

[0041] A lay-up of continuous reinforcing fibers in the present invention refers to the location of the fibers in the matrix and can refer variously to fiber direction and / or fiber density and / or fiber pattern. Thus, the fiber density and / or direction and / or fiber pattern of a first portion of a part can be different compared to the fiber density and / or direction and / or pattern of a second portion of the same part. The first portion of the part can have a higher fiber density than the second portion. In an embodiment, the second portion can be substantially free of continuous fiber reinforcement. Additionally or alternatively, there can be multiple portions with a first lay-up and multiple portions with a second lay-up within an individual part. An individual part can also include one or more regions with a third or further lay-up. Typically, the fiber density is highest in the amount of the part determined to be most highly stressed during use.

[0042] Continuous fiber reinforcement can be placed in a given area of ​​a part to enhance the mechanical properties of that area, such as strength, stiffness, creep resistance, high temperature stability, fatigue resistance, etc. The strategic positioning and layering of fibers reduces cost, weight, and material usage compared to traditional composites or base polymers.

[0043] Typically, the fatigue life of the blades will be sufficient to prevent fatigue failure during the life of the product, and preferably will exceed 20,000 fatigue cycles, each cycle involving running the vacuum pump from zero to full speed and back.

[0044] Typically, the creep resistance of the blades is such that the impeller can operate for 10 years without creeping more than 0.5 mm. Preferably, such creep resistance should be achieved at rotor temperatures of 100° C. or greater.

[0045] The rotor blades are preferably stable at a predetermined operating temperature, typically between about 100° C. and about 150° C., although higher and lower operating temperatures are contemplated.

[0046] The continuous fiber reinforced matrix material preferably comprises a printed composite filament. A composite filament is understood to be a continuous reinforcing fiber comprising a continuous reinforcing core wetted or pre-embedded with a matrix material or matrix binder. The reinforcing core may be a continuous solid core or may comprise a continuous multistrand core. The composite filament may be a continuous carbon fiber pre-embedded in a thermoplastic polymer.

[0047] The continuous fiber reinforced matrix material preferably comprises a molten filament matrix. Molten filament matrix is ​​understood to be a matrix produced using molten filament processing, an additive manufacturing method in which a supply of continuous filaments, such as thermoplastic polymers, is fed through a heated printer extruder head, which melts and deposits the molten material onto a working surface or growing part. The head and working surface move relative to each other to define the print geometry. Typically, the head moves in layers, moving in two dimensions at a time to deposit one horizontal plane before moving slightly upwards to start a new slice. The speed of the extruder head can also be controlled to stop and start the deposition, forming interrupted planes.

[0048] Thus, in a second aspect, the present invention provides a vacuum system in which one or more components comprise a continuous fiber reinforced matrix material, the continuous fiber reinforced matrix material comprising molten composite filaments and a molten filament matrix, typically the composite filaments and the matrix filaments being printed.

[0049] As with the above and below disclosed aspects of the invention, it is preferred that the type and / or layup of the reinforcing continuous fibers in a first portion of an individual component differs from that in a second portion of the same part, such that at least one mechanical property of the first portion of an individual component differs from that of the second portion of the same part.

[0050] In all aspects employing continuous composite filaments, suitable continuous core fibers or strands include materials that provide desired properties such as structural properties, (electrical and / or thermal) conductivity, (electrical and / or thermal) insulation, optical properties, and / or fluid transport properties. Such materials include, but are not limited to, carbon fibers, aramid fibers, glass fibers, metals (such as copper, silver, gold, tin, steel), optical fibers, and flexible tubing. Additionally, multiple types of continuous cores can be used in a single continuous core reinforced filament to provide multiple functionalities such as electrical and optical properties. It is also understood that a single material can be used to provide multiple properties to the core reinforced filament. For example, a steel core can be used to provide both structural properties and electrical conductivity.

[0051] The ability to introduce conductive, photoconductive and / or fluid conductive cores into individual components has the advantage of allowing the construction of functional components within a structure in addition to different mechanical properties. For example, continuous conductive and photoconductive cores can be used to construct strain gauges, optical sensors, wiring and other suitable components. Fluid conductive cores can also be used to form components such as fluid channels and heat exchangers.

[0052] The continuous matrix fibers can also be provided in a variety of sizes. For example, the continuous matrix fibers can have an outer diameter of about 0.025 mm or more and about 10 mm or less. In one specific embodiment, the outer diameter of the matrix fibers is about 0.25 mm or more and about 1 mm or less. In some embodiments, it is also desirable for the core reinforced filament to include a substantially constant outer diameter along its length.

[0053] Additionally or alternatively, the matrix material may be a polymer matrix or a metal matrix.

[0054] In embodiments where the matrix is ​​a polymer matrix, the polymer may be selected from the group consisting of thermosets, thermoplastics, elastomers, and combinations thereof. For example, suitable resins and polymers include, but are not limited to, acrylonitrile butadiene styrene (ABS), epoxy, vinyl, nylon, polyetherimide (PEI), polyetheretherketone (PEEK), polylactic acid (PLA), liquid crystal polymers, and various other thermoplastics. The core may also be selected to provide any desired properties.

[0055] In embodiments where the matrix is ​​a metal matrix, the matrix may comprise a material selected from the group consisting of aluminum, stainless steel, titanium, nickel, and alloys thereof, including aluminum magnesium scandium alloy.

[0056] In an embodiment, the component is a blade or a substantially annular array of blades, and typically the first portion comprises a peripheral edge of a blade and / or the second portion comprises a generally central portion of the same blade.

[0057] The invention therefore provides, in a further aspect, a rotor assembly for a turbomolecular pump comprising an annular hub and one or more substantially annular blade arrangements, each blade arrangement including a plurality of substantially identical blades each extending radially from a blade root adjacent the hub to a blade tip, each blade including a lattice core, typically additively manufactured, e.g. 3D printed, lattice core.

[0058] In this and the previous aspects, the lattice core can have a closed or open cellular structure, and thus can include continuous or discontinuous pore space.

[0059] The lattice core can be of a stochastic or periodic structure. Periodic structures usually have much higher strength than stochastic structures. A person skilled in the art will select the lattice structure depending on the requirements of a particular blade. Periodic lattice structures useful in the present invention include cubic lattice structures, octet truss lattice structures, and hexagonal lattice structures.

[0060] The lattice structures used can be of the uniform or graded type. In a uniform lattice structure, the size and dimensions of each elementary structure are constant throughout the part. In a graded lattice structure, the dimensions of each elementary lattice structure and the cross section of the trusses vary throughout the part. Graded lattice structures can be used to vary the density of the part. Thus, for the same material, a denser lattice will be stronger and stiffer, but will add more mass. The properties of the structure can be locally optimized to tailor the performance within the part to the specific application.

[0061] Additionally or alternatively, the lattice structure may be conformal, i.e. oriented according to the morphology and orientation of the surface of the component, or non-conformal, i.e. independent of the morphology of the surface of the component.

[0062] Typically, the lattice core is completely enclosed within itself and is therefore not visible from the exterior of the blade. Typically, an outer sheet completely surrounds the lattice core. Typically, the sheet and the truss or trusses forming the lattice are continuous. Preferably, the sheet and the truss or trusses forming the lattice are of unitary construction.

[0063] The employment of a lattice structure in each rotor advantageously reduces the mass of the structure while utilizing precise lattice geometry and / or continuous fiber placement to achieve the desired mechanical performance.

[0064] Typically, each rotor is of unitary construction, and preferably each blade assembly is in the form of a unitary construction.

[0065] As described in other aspects of the invention, the rotor assembly may include a continuous fiber reinforced matrix material.

[0066] The invention provides in a further aspect a method for manufacturing a component of a vacuum system comprising a continuous fiber reinforced matrix material, the method comprising melting continuous composite filaments and matrix filaments to form a component such that at least one mechanical property of a first portion of an individual component differs from a mechanical property of a second portion of the same component by virtue of the type and / or lay-up of the reinforcing continuous fibers of said first portion of the individual component differing from a mechanical property of a second portion of the same component.

[0067] 1. A method of manufacturing a rotor blade assembly for a vacuum system, the method comprising: supplying continuous reinforcing filament and matrix material to a print head configured to receive the reinforcing filament and matrix material; heating the reinforcing filament and matrix material in at least one nozzle as the reinforcing filament and matrix material move out of the at least one nozzle; depositing the heated reinforcing filament and matrix on a print bed; and moving the print bed and / or the print head relative to one another to form a rotor blade assembly.

[0068] The continuous reinforcing filament fed to the print head is preferably in the form of a composite filament comprising a continuous reinforcing core pre-embedded in a polymer, typically a thermoplastic polymer. The print head is preferably fed with a single thermoplastic filament. Typically the thermoplastic filament comprises the same or a different polymer as the composite filament.

[0069] As with other embodiments, the continuous fibers may be selected from the group consisting of carbon fibers, glass fibers, aramid fibers, metal fibers, or other fibers described herein, and / or combinations thereof.

[0070] In a further aspect, the invention provides a method of designing a blade assembly for a vacuum system, the method comprising the steps of identifying different mechanical property requirements for portions of the blade assembly when in use, selecting a lay-up using a continuous filament reinforced matrix material that provides the identified different mechanical property requirements of the part, and manufacturing the blade assembly having the selected lay-up using an additive manufacturing process, preferably a composite filament manufacturing process. The different mechanical property requirements can be identified using finite element analysis.

[0071] Preferred features of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0072] [Figure 1] FIG. 1 shows a schematic representation of a rotor blade assembly according to the present invention. [Diagram 2] FIG. 1 shows a schematic representation of a rotor blade assembly according to the present invention. [Diagram 3] FIG. 1 shows a schematic representation of a rotor blade assembly according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0073] The present invention provides a vacuum system including a part having a unitary structure including a continuous fiber reinforced matrix material, where the type and / or layup of reinforcing continuous fibers in a first portion of the part is different from that in a second portion of the part, such that the magnitude of at least one mechanical property of the first portion differs from the magnitude of the mechanical property of the second portion.

[0074] Typically, the component is a moving part of a vacuum system in use, and the first portion has a higher stiffness and / or modulus of elasticity than the second portion. Additionally or alternatively, the first portion may have a higher creep resistance than the second portion. Preferably, the component is a blade. Typically, the first portion comprises the blade root and the second portion comprises the body of the blade. Preferably, the blade root is the portion of the blade that has the highest stiffness and creep resistance.

[0075] As previously disclosed, the present invention further provides a rotor assembly for a vacuum pump including a hub and one or more blade arrangements, each blade arrangement having one or more blades extending from a blade root adjacent the hub to a blade tip, each blade including a continuous fiber reinforced matrix material and continuous fibers extending from each blade to a portion of the hub immediately adjacent the blade.

[0076] During full speed operation, blade roots, such as those of a turbomolecular pump, are subject to very high stresses. The centrifugal forces on the blade depend on the rotational speed, the blade shape and the mass of the blade. Usually the blade shape and rotational speed are fixed for known performance.

[0077] The present invention allows for the use of lower density composite materials in the manufacture of the blades, which reduces stresses at the blade root, allowing for higher rotational speeds, improving rotordynamic performance, and allowing the blades to reach full speed with less energy.

[0078] Strengthening the root of the turbo blades reduces the effects of creep by strengthening the areas of highest stress. The use of reinforcing fibers strategically placed within the blades can also help resist twisting forces, keeping the blades in position and reducing blade twisting under high loads that can change the blade's shape and adversely affect performance.

[0079] FIG. 1 shows an example of a rotor blade assembly (1) according to the present invention suitable for use in an Edwards™ turbomolecular pump. The assembly (1) includes an annular hub (2) and an array of rotor blades (3) extending radially from the hub (2). The intersection (4) between each blade (3) and the rotor hub (2) is called the blade root. A blade edge (5) extends around the periphery of the blade (3) and includes a blade tip (6) at the radially outermost extremity of the blade (3). A blade body (7) extends in a substantially planar manner from the blade root (4) to the blade tip (6). The exact shape of the blades (3) and rotor blade assembly (1) will depend on the characteristics of the associated pump.

[0080] The shape and configuration of the fiber layup can be optimized for an application and / or within a particular region of a part, e.g., cylindrical lay, helical, hatched, mesh, planar, orbital, etc. The fibers can be internal or external. The blades can have a continuous exterior polymeric or metallic surface, e.g., with no continuous fibers present, to provide a superior surface finish and / or tailor performance and / or reduce outgassing.

[0081] The exemplary blade in Figure 1 shows continuous fiber planar (8) and track (9) layups diagrammatically. The illustrated layups provide resistance to torsional and radial stiffness, respectively. The continuous fiber matrix may be continuous carbon fiber in a nylon matrix.

[0082] 2 shows a further configuration in which continuous fibers (10) traverse the root (4) of the blade (3), which advantageously reduces creep in the root portion of the rotor assembly (1).

[0083] Yet another configuration is shown in Figure 3 in which the annular rotor hub (2) is reinforced with helically arranged continuous fibers (11) to strengthen the hub and prevent deformation during use.

[0084] The components and rotor assemblies of the present invention can be manufactured using a Markforged™ X7 carbon fiber printer.

[0085] It will be understood that various modifications can be made to the illustrated embodiments without departing from the spirit and scope of the invention as interpreted under the patent laws, as defined by the appended claims. [Explanation of symbols]

[0086] 1. Rotor Assembly 2. Annular hub 3. Moving blade 4. Blade root 5. Blade Edge 6. Tip of rotor blade 7. Rotating blade body 8. Planar continuous fiber layup 9. Orbital Continuous Fiber Layup 10. Continuous Fiber 11. Spiral Lay-Up

Claims

1. 1. A rotor assembly for a vacuum pump comprising: a hub; and one or more blade arrangements, each blade arrangement having at least one blade extending from a blade root adjacent the hub to a blade tip, the blades comprising a continuous fiber reinforced matrix material having a plurality of printed layers disposed in respective planes, at least one of the plurality of printed layers including continuous fibers lying within the plane of the at least one printed layer and extending from the blade to a portion of the hub immediately adjacent the blade, a type and / or layup of continuous fibers for reinforcing varies between the blade root and the blade tip, and the continuous fibers have a length of at least 0.5 m.

2. the rotor assembly is for a turbomolecular pump, the hub comprising a substantially annular hub, the one or more blade arrangements comprising substantially annular blade arrangements, each blade arrangement having a plurality of substantially identical blades, each blade extending radially from a blade root adjacent the hub to a blade tip, each blade comprising a continuous fiber reinforced matrix material comprising a plurality of printed planar layers, at least one of the printed planar layers comprising continuous fibers extending from the blade to a portion of the hub immediately adjacent the blade; The rotor assembly of claim 1 .

3. a plurality of blade arrays; A rotor assembly according to claim 1 or 2.

4. the blade root and / or the blade tip have a higher tensile strength and / or a higher bending strength and / or a higher creep resistance than the remainder of the blade; A rotor assembly according to any one of claims 1 to 3.

5. the hub and blades comprise substantially similar or identical matrix materials; A rotor assembly according to any one of claims 1 to 4.

6. The continuous fiber reinforced matrix material comprises a fused filament matrix. A rotor assembly according to any one of claims 1 to 5.

7. The continuous fiber reinforced matrix material includes molten composite filaments and a molten filament matrix. A rotor assembly according to any preceding claim.

8. The continuous fibers are selected from the group consisting of carbon fibers, glass fibers, aramid fibers, metal fibers, and / or combinations thereof. A rotor assembly according to any preceding claim.

9. The matrix is ​​a polymer matrix or a metal matrix. A rotor assembly according to any preceding claim.

10. the matrix is ​​a polymer matrix, the polymer being selected from the group consisting of thermosets, thermoplastics, elastomers, and combinations thereof; A rotor assembly according to any preceding claim.

11. Each blade includes a lattice core. A rotor assembly according to any preceding claim.

12. an outer sheet completely surrounds the lattice core; The rotor assembly of claim 11.

13. The sheet and lattice core are in the form of a unitary structure. The rotor assembly of claim 12.

14. 1. A method of manufacturing a vacuum pump blade assembly, each blade assembly including at least one blade extending from a blade root adjacent a hub to a blade tip, the blade including a continuous fiber reinforced matrix material, the method including the steps of melting continuous composite filaments to form a planar layer including continuous fibers, and melting the matrix material to form a planar layer of matrix material, the planar layer including continuous fibers defining a portion of the blade and a portion of the hub, whereby the continuous fibers extend from the blade to a portion of the hub immediately adjacent the blade root, the continuous fibers having a length of at least 0.5 m. A method comprising:

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