Extraction device with buckets and manufacturing method provided therefor

Description

Technical field

[0001] The invention relates to an extraction device for drawing in chips and / or dust generated during the cutting of a workpiece, particularly for a chuck for holding a rotary-driven cutting tool, especially a cutting tool for machining CFRP materials or other short-chipping materials. The invention further relates to a method for manufacturing such an extraction device.

[0002] Especially when machining CFRP materials or other short-chipping materials, fine chips are produced during the machining process, i.e., when fibers of the (CFRP) material are removed. These chips adhere to the tool and the workpiece, thus impairing the machining result. To prevent this, extraction systems known from the prior art are often used to remove the resulting chips and / or dust.

[0003] Among other things, DE 37 34 127 A1 discloses a machine for machining, wherein an extraction device for the removed chips is provided, which has a chip collection chamber connected to a suction pump. The chip collection chamber is surrounded by a boundary wall, the edge of which facing the workpiece defines a passage opening for the tool and can simultaneously be axially displaced on the workpiece surface. However, such an extraction device achieves an insufficient extraction result because the suction power is too low and the suction pump is only connected to individual inlet openings.

[0004] EP 3 100 821 A2 further discloses a suction device with the features of the preamble of claim 1, namely a cleaning turbine with a bell and a plurality of slots arranged around the circumference of the bell and extending radially through the bell as through holes.

[0005] Furthermore, US 2014 / 020919 A1 discloses a rotary tool with a collet chuck designed to hold a tool which has a fan mechanism with a multitude of blades which serves to direct / blow air forward, i.e. towards the workpiece.

[0006] EP 2 422 925 B1 also discloses a removal device for removing particles from a machining tool, wherein a fan wheel is used to generate an airflow for removing particles produced during machining. The fan wheel can be attached to the machining tool in such a way that it rotates with the machining tool around its machining axis. Additionally, a separator is positioned upstream of the fan wheel to separate the particles from the airflow in front of the fan wheel. However, it has been found that the suction capacity achievable with this device is relatively limited due to poorly controllable imbalance forces.

[0007] Furthermore, EP 2 644 318 A1 discloses a tool holder, a tool and an extraction device which rotates together with the tool and is designed to remove chips produced during cutting operations on a workpiece, wherein the extraction device is detachably connected to the tool holder and includes a bell-shaped body which forms an extraction chamber around the tool and has a plurality of openings in its side wall.

[0008] Apart from the fact that handling this extraction device and assembling the necessary components is complex and prone to errors, this well-known device also demonstrates that it cannot achieve the suction power required for modern high-performance machining of CFRP materials.

[0009] The object of the invention is therefore to avoid or reduce the disadvantages of the prior art. In particular, it aims to provide an extraction device for a chuck that, while being easy to manufacture and assemble, is characterized by a suction performance that has not been achieved to date. Furthermore, an economical manufacturing process for such an extraction device is to be developed.

[0010] The object of the invention is achieved by a suction device with the features of claim 1 and a method for manufacturing a suction device with the features of claim 11. Advantageous embodiments are the subject of the dependent claims.

[0011] In other words, each blade leading edge or inner edge extends radially outwards from an end of the blade located radially inside the hub section and axially away from the hub section, i.e., towards a workpiece or a tool-side end of the extraction device, up to the ring section. This creates an axially extending, coaxially arranged, bell-shaped section, for example, from which the multitude of radial blades extend radially inwards. This concept results in the leading edges of the radial blades being designed and arranged such that the radial distance between a longitudinal axis of the extraction device and the respective blade leading edge to the tool-side end, i.e., to an ring-section-side end of the extraction device, increases progressively.

[0012] In the suction device, the blades and the ring section form a paddle wheel with a tool-side, continuously annular suction opening and a plurality of circumferential outlet openings, wherein the outlet openings correspond to outlet openings of paddle channels formed on a radial outer circumference of the paddle wheel.

[0013] This has the advantage that not only is a relatively large intake opening formed upstream of the blades in the area of ​​the ring section, but also an increased suction volume, thus raising the suction performance of the blades to a previously unattainable level. This makes the extraction device particularly suitable for extracting chips and / or dust, even when extremely large numbers of very small chips or dust particles are generated, as is the case, for example, with high-performance machining of CFRP materials. Tests have shown that even a chip jet generated during this type of machining can be reliably captured by the impeller and transported away from the workpiece surface.

[0014] This, in turn, has the advantage that no suction chamber surrounding the blades is required, since even when arranged in a machine tool machining area without a suction chamber, the chips and / or dust are reliably transported away. This significantly simplifies tool changes during machining, as the extraction device and thus also a clamping section for holding a tool are freely accessible.

[0015] Furthermore, it is advantageous if the outer diameter of the hub section, the ring section, and / or the blades forms a common cylindrical shell whose surface encloses the suction device. This allows for a particularly compact and therefore versatile suction device, and it has been shown that this design permits a significant increase in the permissible rotational speed.

[0016] It is also preferred if the outer diameter of the hub section, the ring section, and / or the blades form a common rotationally symmetrical enclosing surface, the outer surface of which surrounds the suction device. Preferably, the enclosing cone tapers axially from the ring section towards the hub section. This allows for a larger blade area and a larger intake opening, thus further increasing the suction capacity. The enclosing surface can assume various shapes to influence the required suction capacity. In the simplest design, it is formed by a cylindrical enclosing element, which keeps the mass of the suction device low, ensuring that dynamic forces remain manageable even at very high rotational speeds. The enclosing surface can also be formed by a conical enclosing element that tapers axially from the ring section towards the hub section.This allows for an enlarged blade area to be formed simultaneously with a large intake opening, thus further increasing the suction power.

[0017] Furthermore, it is advantageous if the blades are angled axially and / or radially and / or circumferentially. It is preferred if the respective longitudinal axes of the blades are inclined relative to a longitudinal axis of the suction device, for example circumferentially, to the axial direction, preferably by at least 10°, more preferably by 15° to 35°. This advantageously makes it possible to increase the blade area and, in particular, the effective edge length of the blade while maintaining a constant axial extent.

[0018] It is also preferred if the respective longitudinal axes of the blades are inclined radially to a longitudinal axis of the suction device, preferably by at least 15°, more preferably by 20 to 30°. The longitudinal axis of the suction device corresponds to a longitudinal axis of the hub section or the ring section. This advantageously allows the suction flow for drawing in the chips and / or dust to be generated and directed in a predetermined direction.

[0019] Furthermore, a preferred embodiment is characterized by the fact that the respective blades have a positive curvature, preferably a consistently positive curvature. This allows the direction of rotation of the hub section to be used particularly effectively to generate the greatest possible suction flow or suction power. Alternatively, it is also possible for the blades to have a negative curvature.

[0020] It is particularly preferred if the blades are curved in the circumferential direction and / or in the longitudinal axis direction. This allows for a particularly advantageous blade design for generating a suction flow with a flow velocity of up to 20 m / s.

[0021] Additionally, it is advantageous if the blades have a continuous cross-section over more than half the length of the suction device along its longitudinal axis. This allows a large usable blade area to be utilized for generating the suction flow. This advantageously enables a short axial design while maintaining high suction capacity, since a relatively large portion of the suction device's length can be used for the usable blade length. In other words, as much of the available blade length as possible is used to generate the suction flow.

[0022] According to an advantageous further development, the extraction device is integral, i.e., manufactured as a single piece of material. This allows, for example, the blades of the extraction device to be precisely aligned with each other and / or with the hub section during manufacturing. The tolerances are therefore not dependent on assembly accuracy. Furthermore, this allows the extraction device to be easily assembled as a whole, which has a positive impact on manufacturing costs and assembly time.

[0023] It has been shown above that the extraction device is distinguished by its unprecedented suction performance, achieved through a special blade arrangement and geometry. This blade arrangement and geometry can be optimized particularly economically if the extraction device is manufactured additively, i.e., using an additive manufacturing process. Additive manufacturing advantageously allows for the highly precise creation of complex geometries, such as those of the blades.

[0024] Furthermore, it is advantageous if the extraction device, a clamping section of the chuck for receiving a rotary-driven cutting tool and a shank section of the chuck form a modular structure, so that the extraction device can advantageously also be used independently of the clamping section and the shank section.

[0025] According to a particularly advantageous embodiment, the hub section or the extraction device is integrally formed with the clamping section of the chuck for receiving a rotary-driven cutting tool. This ensures highly precise centering of the hub section, and thus also of the blades, relative to the clamping section, so that forces caused by imbalance remain easily manageable with reduced assembly effort. This guarantees exceptionally smooth operation of the extraction device even at extremely high speeds, while simultaneously eliminating conventionally occurring assembly errors. In other words, the hub section, the clamping section, the blades, and the ring section are additively manufactured together as an integral unit. A unit consisting of the hub section, the blades, and the ring section is subsequently referred to as a cage.This allows the extraction device to be manufactured in a single process, for example by 3D printing, thus eliminating time-consuming and costly post-processing and / or assembly.

[0026] Furthermore, it is advantageous if the extraction device is attached to a shaft section, for example, a hollow shaft cone, of the chuck. It is particularly preferred if the hollow shaft cone is manufactured conventionally and the extraction device is printed onto the shaft section, for example, by 3D printing. This results in a hybrid design for the chuck, allowing the additively manufactured extraction device to be combined with the shaft section, which is preferably designed as a standard component. This combines the advantages of additive manufacturing with those of conventional manufacturing, significantly reducing production costs.

[0027] It is particularly preferred if the extraction device is manufactured by selective laser melting. In this process, the material to be processed is applied in powder form in a thin layer to a base plate and locally melted or remelted completely by means of laser radiation. After solidification, a solid material layer is formed. The base plate is then lowered by the thickness of the applied layer, and more powder is applied until all layers have been remelted.

[0028] Furthermore, it is advantageous if the suction device is preferably manufactured layer by layer from an end on the hub section side to an end on the ring section side. This allows for the production of an optimal blade shape, particularly at the hub section side end.

[0029] Additionally, it is preferred if at least one channel is formed in the hub section, which advantageously saves material within the hub section and thus reduces manufacturing time, particularly 3D printing time. Furthermore, it is advantageous if the channel has a C-shaped cross-section and is preferably bent concentrically to the longitudinal axis of the extraction device. According to an advantageous embodiment, several channels are provided, which are preferably arranged radially nested.This means that, for example, with three channels, a first channel is formed in an arc on a first circle concentric to the longitudinal axis, a second channel is formed in an arc on a second circle concentric to the longitudinal axis, the second circle having a larger radius than the first, and a third channel is formed in an arc on a third circle concentric to the longitudinal axis, the third circle having a larger radius than the second. The channels are produced by not melting the powder in the channel area during manufacturing. The powder remains in the channels because it also has a beneficial effect on the damping properties.

[0030] Furthermore, it is advantageous to have a chamber in the hub section, preferably with a circular arc cross-section and preferably concentric to the longitudinal axis. This advantageously allows for savings in the amount of material to be printed, thus further reducing production time, and also enables the chamber to serve as a pre-balancing chamber, thereby reducing forces caused by imbalance. During production, the powder in the area of ​​the pre-balancing chamber is not melted and is subsequently removed from the extraction device through a radially extending through-opening.

[0031] It is particularly preferred if the clamping section is designed such that the blades, as well as the inlet and outlet openings of blade channels, which are formed between adjacent blades, are located around the clamping section. This allows the chips and / or dust particles generated by a cutting tool held in the clamping section to be guided radially outwards away from the cutting tool and thus away from the workpiece being machined, via the blade channels.

[0032] Furthermore, it is advantageous if the clamping section, which is preferably truncated cone-shaped or truncated parabola-shaped, tapers axially towards a distal end, i.e., a tool-side end or an annular-section-side end, of the extraction device. Preferably, a radial outer circumferential surface of the clamping section forms an angle of at most 10°, preferably at most 5°, and more preferably 2° to 4°, with the longitudinal axis of the extraction device. This creates suitable flow characteristics around the clamping section to maximize the suction flow and suction power.

[0033] Furthermore, it is advantageous if the clamping section is axially flush with the ring section. In other words, it is preferred if the section from the hub section to the ring section extends axially over at least half of the axial length, preferably over at least 90% of the axial length, and more preferably over the entire axial length, of the extraction device. This ensures optimal utilization of the extraction device's axial length.

[0034] It is also advantageous if the clamping section has a hydraulic expansion clamping area or a collet mechanism. This ensures that a cutting tool to be held in the clamping section can be clamped precisely in the center. This prevents decentering or axial misalignment and the resulting imbalance.

[0035] According to an advantageous embodiment, the angle of attack of the blades can change in the radial and / or axial direction over the blade extension.

[0036] Furthermore, it is advantageous if the blades and the ring section form an impeller with a continuously annular suction opening on the tool side, i.e., with a continuous annular cross-section, and a plurality of circumferential outlet openings. The outlet openings correspond to the discharge openings of the blade channels, which are formed on the radial outer circumference of the impeller. In particular, it is preferred if the blade channels extend from the hub section to the ring section.

[0037] Furthermore, it is preferred if the longitudinal edges of the outlet openings are oriented essentially parallel to each other. The outlet openings extend essentially perpendicular to a radial direction of the extraction device, so that the chips can be guided (away) radially outwards.

[0038] Furthermore, it is advantageous if the extraction device is arranged in a machine tool machining area in which a swirling flow is generated to remove the chips and / or dust from the machining area. In a preferred embodiment, the swirling flow is designed as a transverse flow in the machine tool machining area, oriented perpendicular to the longitudinal axis of the extraction device.

[0039] The invention also relates to a chuck for rotary-driven cutting tools, comprising a shank section, a clamping section for force-fit clamping of a rotary-driven cutting tool and an extraction device according to the invention arranged non-rotatably on the clamping section for sucking up chips and / or dust produced during the cutting of a workpiece.

[0040] The object of the invention is also achieved by a method for manufacturing a suction device according to the invention, in particular for a chuck, wherein the method comprises the following steps: determining a suction power required for the suction process from an engagement area of ​​a cutting tool with respect to speed and volume; creating a computational model for the design of a plurality of vanes of the suction device; optimizing the vane design in the computational model with respect to a generated suction power; and additive manufacturing of the computational model.

[0041] This has the advantage that, depending on the application of the extraction device, the blades can be designed in such a way that the suction performance is optimized for the respective application. Additive manufacturing of the extraction device allows for the production of complex geometries that correspond to a calculation model of the extraction device, and in particular the blades, optimized with regard to the suction performance to be achieved. Brief description of the characters

[0042] The invention is explained below with the aid of drawings. These show: Fig. 1 a semi-longitudinal section view of a suction device according to the invention, which is attached to a shaft section, Fig. 2 a longitudinal sectional view of the suction device and the shaft section along line II-II, Fig. 3 a cross-sectional view of a hub section of the suction device along the in Fig. 1 depicted line III-III, Fig. 4a front view of the extraction device, Fig. 5 a longitudinal section view of the extraction device along the in Fig. 4 depicted line IV-IV, Fig. 6 a longitudinal section view of the extraction device along the in Fig. 4 depicted line VI-VI, Fig. 7 a perspective side view of the extraction device with the shaft section, Fig. 8 a perspective front view of the extraction device, Fig. 9 a perspective view obliquely from the front of the extraction device, and Fig. 10 A schematic, perspective view of the extraction device from an oblique angle above. Description of the exemplary implementations

[0043] The figures are purely schematic and serve solely to illustrate the invention. The same elements are identified by the same reference symbols.

[0044] Fig. 1 to 10Figure 1 shows a suction device according to the invention, which is part of a chuck 10. A cutting tool 12 can be held in the chuck 10. The suction device has a rotatably driven hub section 14. A plurality of radial blades or blades 16 extend axially from the hub section 14, the blades 16 being evenly distributed circumferentially around the hub section 14. The blades 16 extend from the hub section 14 to a ring section 18 arranged coaxially but axially spaced from the hub section 14. The hub section 14, the blades 16, and the ring section 18 form a cage-like, one-piece unit, which is also called a paddle wheel.

[0045] The blades 16 each have a blade leading edge 20, which forms a radial inner edge of the blade 16 or the blade surface. The blade leading edge 20 extends axially away from the hub section 14 and radially outwards, transitioning into the ring section 18. The ring section 18 thus stabilizes the blades 16. The radial distance between the longitudinal axis of the suction device and the respective blade leading edges 20 therefore increases with increasing extension length from the hub section 14 towards the ring section 18.

[0046] Radially within the ring section 18, a clamping section 22 is formed to receive the cutting tool 12, around which the blades 16 are arranged. The clamping section 22 is arranged coaxially with the ring section 18 and the hub section 14. A shaft section 24 adjoins the hub section 14 axially on a side facing away from the ring section. The hub section 14, the blades 16, the ring section 18, and the clamping section 22 are 3D printed onto the shaft section 24, forming a permanently bonded unit.

[0047] The clamping section 22 has a hydraulic expansion clamping area 26 with two pressure chambers 28. A first pressure chamber 28A is hydraulically connected to a second pressure chamber 28B, which is arranged axially offset from the first pressure chamber 28A. The pressure chambers 28 can be pressurized via a hydraulic channel 30, causing an elastically compliant partition between the pressure chambers 28 and a tool holder section to deform radially inwards, thus achieving centered clamping of the cutting tool 12 in the clamping section 22. The hydraulic channel 30 is fluidly connected to a hydraulic port in the shank section 24. Such hydraulic expansion chucks are known per se, so a detailed description is unnecessary.

[0048] The radial outer diameter of the clamping section 22 tapers continuously from a hub-side end to an annular-side end. The clamping section 22 thus has a conical radial outer circumferential surface. At its annular-side end, the clamping section 22 terminates axially flush with the annular section 18, and at its hub-side end, it transitions into the hub section 14.

[0049] In an alternative embodiment, the extraction device can also be designed without the clamping section 22, even if this is not shown in the drawings.

[0050] In Fig. 3Figure 1 shows a cross-section of the hub section 14. The hub section 14 has a balancing chamber 32 which has a circular arc-shaped cross-section. The balancing chamber 32 is connected to a radial outer circumference of the hub section 14 via a radially extending through-opening 34.

[0051] The hub section 14 contains several C-shaped or arc-shaped channels 36. A first channel 26A is arranged along a first circle concentric with the longitudinal axis of the hub section 14. Two second channels 36B are arranged along a second circle concentric with the longitudinal axis of the hub section 14, which has a larger diameter than the first circle. The two second channels 36B are arranged symmetrically with respect to a plane of symmetry containing the longitudinal axis. Two third channels 36C are arranged along a third circle concentric with the longitudinal axis of the hub section 14, which has a larger diameter than the second circle. The two third channels 36C are arranged symmetrically with respect to the plane of symmetry.The pre-balancing chamber 32 is arranged along a circle concentric with the longitudinal axis of the hub section 14, the diameter of which is larger than that of the second circle and smaller than that of the third circle. The second channels 36B and the third channels 36C each extend over a length of 1 / 8 to 1 / 4, preferably about 1 / 6, of the circumference of the second and third circles, respectively. The first channel 36A extends over a length of 3 / 4 to the entire circumference of the first circle, preferably about 7 / 8 of the circumference of the first circle.

[0052] As in Fig. 2 As can be seen, the channels 36 and the pre-balancing chamber 32 extend axially to a shaft-side end of the hub section 14 and to a base of the blades 16. The width of the channels 36 and the pre-balancing chamber 32 tapers radially towards the blades 16.

[0053] The blades 16, or rather their longitudinal axes, are inclined to the axial direction of the suction device along the circumferential direction. The blades 16, or rather their longitudinal axes, are also inclined to the radial direction of the suction device along the axial direction.

[0054] In other words, the longitudinal axes of the blades 16 run radially from the inside to the outside, viewed from a hub-section end to a ring-section end, and circumferentially in the direction of rotation. The blades 16 are therefore angled both radially and axially, with the angle of attack changing along the blade's length.

[0055] Between each pair of circumferentially adjacent blades 16, a blade channel 38 is formed. Each blade channel 38 has an outlet opening located on the radial outer circumference of the impeller. These outlet openings coincide with the outlet openings of the impeller. The blades 16 have a triangular cross-sectional shape, formed by the blade leading edges 20 and two blade exit edges 40 located on the radial outer circumference of the impeller. The blade exit edges 40 correspond to the longitudinal edges of the outlet openings of the impeller and the outlet openings of the blade channels 38, respectively.

[0056] The blade trailing edges 40 are essentially parallel to each other and are angled axially such that the length of the blade trailing edges 40 is greater than the axial extension length of the blades 16. The blade leading edges 20 extend in a curved axial direction away from the hub section 14 and radially outwards, with the curvature increasing with increasing distance from the hub section 14, i.e., the radius of curvature of the blade leading edges 20 decreases with increasing distance from the hub section 14 (compare Fig. 5 and 6 ).

[0057] At the tool-side end of the impeller, a continuous annular suction opening 42 is formed, which is concentric to the clamping section 22. A larger suction opening has a positive effect on the suction power that can be generated.

[0058] The impeller is manufactured integrally with the clamping section 22 using a 3D printing process. The impeller and clamping section 22 are produced from a shaft-side end and printed onto the shaft section 24, forming an inseparable unit consisting of the shaft section 24, the clamping section 22, and the impeller. A radial outer circumferential surface of the hub section 14 transitions into a radial outer circumferential surface of the shaft section 22. This means that there is no step between the shaft section 24 and the impeller. During manufacturing, the impeller and clamping section 22 are applied layer by layer in the axial direction. For manufacturability reasons, a triangular section 44 is present in a transition area between the ring section 18 and the blades 16, the outer edges of which each form an obtuse angle with the blades 16 and the ring section 18 (see Figure 1). Fig. 7 to 10 ).

[0059] The extraction device is used in a machine tool machining area, where a flushing flow is generated that flows perpendicular to the longitudinal axis of the extraction device. The flushing flow is designed to flow radially away from the extraction device and out of the machine tool machining area.

[0060] The above-described setup results in the following operating principle: During a cutting operation with the cutting tool 12 held in the chuck 10, the clamping section 22 is driven in one direction of rotation about a spindle axis. Due to the integral design of the impeller—that is, the hub section 14, the blades 16, and the ring section 18—with the clamping section 22, the impeller is driven during the cutting operation. The design of the blades 16 creates a suction flow that flows from the continuously annular suction opening 42 of the impeller on the tool side, through the blade channels 38, to the outlet openings on the outer circumference of the impeller. This suction flow draws in chips and dust from the workpiece surface being machined and carries them away.The chips and / or dust exiting the outlet openings are then captured by the flushing flow in the machine tool machining area and transported perpendicular to the spindle axis away from the extraction device and out of the machine tool machining area.

Claims

1. A suction device for sucking chips and / or dust generated during a cutting machining of a workpiece, in particular for a chuck (10) for receiving a rotationally driven cutting tool (12), especially a cutting tool for machining CFRP materials or other short-chipping materials, comprising a hub portion (14) that can be rotationally driven, characterized in that the suction device comprises a plurality of radial blades (16) evenly distributed in a circumferential direction and supported by the hub portion (14), wherein in each case a blade entering edge (10) of the blade (16) extends axially away from the hub portion (14) and radially outwards to a ring portion (18) that stabilizes the blades (16) and is concentric with respect to the hub portion (14), wherein the blades (16) and the annular portion (18) form a blade wheel with a continuous annular suction opening (42) on the tool side and a plurality of outlet openings on the circumferential side, wherein the outlet openings correspond to outlet openings of blade channels (38) formed on an outer radial circumference of the blade wheel.

2. The suction device according to claim 1, characterized in that an outer diameter of the hub portion (14), the ring portion (18) and / or the blades (16) form a joint casing cylinder the outer surface of which encloses the suction device.

3. The suction device according to claim 1 or 2, characterized in that the blades (16) are inclined in the axial direction and / or in the radial direction.

4. The suction device according to any one of the claims 1 to 3, characterized in that the blades (16) have a continuously extending blade cross-section over more than half the extension length of the suction device along its longitudinal axis.

5. The suction device according to any one of the claims 1 to 4, characterized in that the suction device is formed integrally in itself.

6. The suction device according to any one of the claims 1 to 5, characterized in that the suction device is generatively produced.

7. The suction device according to any one of the claims 1 to 6, characterized in that the hub portion (14) is formed integrally with a chuck portion (22) of the chuck (10).

8. The suction device according to claim 7, characterized in that the chuck portion (22) is axially flush with the ring portion (18).

9. The suction device according to claim 7 or 8, characterized in that the chuck portion (22) includes a hydraulic chuck area or a collet chuck mechanism.

10. The suction device according to any one of the claims 3 to 9, characterized in that the angle of attack of the blades (16) in the radial and / or axial direction varies along the blade extension.

11. A method for producing a suction device according to any one of the claims 1 to 10 comprising the steps of: - determining a suction power in terms of speed and volume required for the sucking operation from an engaging area of a cutting tool (12); - establishing a calculation model for the configuration of a plurality of blades (16) of the suction device; - optimizing the blade configuration in the calculation model with respect to a suction power produced; - additively producing the calculation model.