WASH PUMP IMPELLER FOR A DISHWASHING APPLIANCE AND A METHOD OF ADDITIVELY MANUFACTURING THE SAME
1. A dishwasher appliance comprising:
- a wash tub defining a wash chamber for receipt of articles for washing;
a sump for collecting wash fluid;
a wash pump impeller in fluid communication with the wash fluid in the sump and being configured for urging a flow of wash fluid into the wash chamber for cleaning articles, the wash pump impeller comprising;
a hub defining a flow surface, an axial direction, a radial direction, and a circumferential direction;
a plurality of vanes integrally formed with the hub, the vanes extending from the hub at an extension angle relative to the flow surface of the hub, the extension angle being less than 60 degrees.
A wash pump impeller for a dishwasher appliance and a method of forming the same using an additive manufacturing process are provided. The wash pump impeller includes a hub and a plurality of vanes integrally formed with the hub and extending at an extension angle of less than 60 degrees relative to a flow surface of the hub and the vanes may be curved in three dimensions. The wash pump impeller is formed by establishing a three-dimensional model of the wash pump impeller, converting that model into slices defining cross-sectional layers of the wash pump impeller, and successively forming those layers using an additive manufacturing process.
- 1. A dishwasher appliance comprising:
a wash tub defining a wash chamber for receipt of articles for washing; a sump for collecting wash fluid; a wash pump impeller in fluid communication with the wash fluid in the sump and being configured for urging a flow of wash fluid into the wash chamber for cleaning articles, the wash pump impeller comprising; a hub defining a flow surface, an axial direction, a radial direction, and a circumferential direction; a plurality of vanes integrally formed with the hub, the vanes extending from the hub at an extension angle relative to the flow surface of the hub, the extension angle being less than 60 degrees.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- 13. A method for forming a wash pump impeller for a dishwasher appliance, the method comprising:
establishing three-dimensional information of the wash pump impeller; converting the three-dimensional information of the wash pump impeller into a plurality of slices, each slice of the plurality of slices defining a respective cross-sectional layer of the wash pump impeller; and successively forming each cross-sectional layer of the wash pump impeller with an additive manufacturing process.
- View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
The present disclosure relates generally to dishwasher appliances, and more particularly to additively manufactured wash pump impellers for dishwasher appliances.
Dishwasher appliances generally include a tub that defines a wash chamber. Rack assemblies can be mounted within the wash chamber of the tub for receipt of articles for washing. Wash fluid (e.g., various combinations of water and detergent along with optional additives) may be introduced into the tub where it collects in a sump space at the bottom of the wash chamber. During wash and rinse cycles, a pump may be used to circulate wash fluid to spray assemblies within the wash chamber that can apply or direct wash fluid towards articles disposed within the rack assemblies in order to clean such articles. During a drain cycle, a pump may periodically discharge soiled wash fluid that collects in the sump space and the process may be repeated.
Conventional dishwasher appliances include injection molded or machined wash pump impellers for urging the flow of wash fluid onto articles for cleaning. Notably, manufacturing limitations associated with these manufacturing processes have historically resulted in inefficient wash pump impellers. More specifically, there are frequently geometrical limitations to the shapes of the impellers, e.g., in order to permit the withdrawal of sliding elements of an injection molding machine. Similarly, machined impellers typically must be designed to permit a machining tool to access all surfaces of the impeller for removing material. Specifically, conventional wash pump impellers are radial-type impellers with two-dimensional vanes.
Notably, conventional wash pump impellers frequently result in various performance limitations of the dishwashing appliance. Specifically, inefficient wash impellers will generally require larger, more expensive motors to drive the impeller and achieve the desired pressure head. In addition to increased part and energy usage costs, larger motors and impellers result in increased torque pulsations and noise.
Accordingly, a dishwasher appliance having features for improved efficiency, lower costs, and reduced noise would be useful. More specifically, a wash pump impeller for a dishwasher appliance that has a high hydraulic efficiency resulting in a quiet, energy efficient, and economical pump assembly would be particularly beneficial.
Aspects and advantages of the invention will be set forth in part in the following description, may be apparent from the description, or may be learned through practice of the invention.
In accordance with one exemplary embodiment of the present disclosure, a dishwasher appliance is provided including a wash tub defining a wash chamber for receipt of articles for washing and a sump for collecting wash fluid. A wash pump impeller is in fluid communication with the wash fluid in the sump and is configured for urging a flow of wash fluid into the wash chamber for cleaning articles. The wash pump impeller includes a hub defining a flow surface, an axial direction, a radial direction, and a circumferential direction. A plurality of vanes are integrally formed with the hub, the vanes extending from the hub at an extension angle relative to the flow surface of the hub, the extension angle being less than 60 degrees.
In accordance with another exemplary embodiment of the present disclosure, a method for forming a wash pump impeller for a dishwasher appliance is provided. The method includes establishing three-dimensional information of the wash pump impeller and converting the three-dimensional information of the wash pump impeller into a plurality of slices, each slice of the plurality of slices defining a respective cross-sectional layer of the wash pump impeller. The method further includes successively forming each cross-sectional layer of the wash pump impeller with an additive manufacturing process.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.
Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention.
Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
As used herein, the term “article” may refer to, but need not be limited to dishes, pots, pans, silverware, and other cooking utensils and items that can be cleaned in a dishwashing appliance. The term “wash cycle” is intended to refer to one or more periods of time during which a dishwashing appliance operates while containing the articles to be washed and uses a detergent and water, preferably with agitation, to e.g., remove soil particles including food and other undesirable elements from the articles. The term “rinse cycle” is intended to refer to one or more periods of time during which the dishwashing appliance operates to remove residual soil, detergents, and other undesirable elements that were retained by the articles after completion of the wash cycle. The term “drain cycle” is intended to refer to one or more periods of time during which the dishwashing appliance operates to discharge soiled water from the dishwashing appliance. The term “wash fluid” refers to a liquid used for washing and/or rinsing the articles and is typically made up of water that may include other additives such as detergent or other treatments. Furthermore, as used herein, terms of approximation, such as “approximately,” “substantially,” or “about,” refer to being within a ten percent margin of error.
The tub 104 includes a front opening 114 and a door 116 hinged at its bottom for movement between a normally closed vertical position (shown in
As best illustrated in
Some or all of the rack assemblies 122, 124, 126 are fabricated into lattice structures including a plurality of wires or elongated members 130 (for clarity of illustration, not all elongated members making up rack assemblies 122, 124, 126 are shown in
Dishwasher 100 further includes a plurality of spray assemblies for urging a flow of water or wash fluid onto the articles placed within wash chamber 106. More specifically, as illustrated in
The various spray assemblies and manifolds described herein may be part of a fluid distribution system or fluid circulation assembly 150 for circulating water and wash fluid in the tub 104. More specifically, fluid circulation assembly 150 includes a pump 152 for circulating water and wash fluid (e.g., detergent, water, and/or rinse aid) in the tub 104. Pump 152 may be located within sump 138 or within a machinery compartment located below sump 138 of tub 104, as generally recognized in the art. Fluid circulation assembly 150 may include one or more fluid conduits or circulation piping for directing water and/or wash fluid from pump 152 to the various spray assemblies and manifolds. For example, as illustrated in
As illustrated, primary supply conduit 154 is used to supply wash fluid to one or more spray assemblies, e.g., to mid-level spray arm assembly 140 and upper spray assembly 142. However, it should be appreciated that according to alternative embodiments, any other suitable plumbing configuration may be used to supply wash fluid throughout the various spray manifolds and assemblies described herein. For example, according to another exemplary embodiment, primary supply conduit 154 could be used to provide wash fluid to mid-level spray arm assembly 140 and a dedicated secondary supply conduit (not shown) could be utilized to provide wash fluid to upper spray assembly 142. Other plumbing configurations may be used for providing wash fluid to the various spray devices and manifolds at any location within dishwasher appliance 100.
Each spray arm assembly 134, 140, 142, integral spray manifold 144, or other spray device may include an arrangement of discharge ports or orifices for directing wash fluid received from pump 152 onto dishes or other articles located in wash chamber 106. The arrangement of the discharge ports, also referred to as jets, apertures, or orifices, may provide a rotational force by virtue of wash fluid flowing through the discharge ports. Alternatively, spray arm assemblies 134, 140, 142 may be motor-driven, or may operate using any other suitable drive mechanism. Spray manifolds and assemblies may also be stationary. The resultant movement of the spray arm assemblies 134, 140, 142 and the spray from fixed manifolds provides coverage of dishes and other dishwasher contents with a washing spray. Other configurations of spray assemblies may be used as well. For example, dishwasher 100 may have additional spray assemblies for cleaning silverware, for scouring casserole dishes, for spraying pots and pans, for cleaning bottles, etc. One skilled in the art will appreciate that the embodiments discussed herein are used for the purpose of explanation only, and are not limitations of the present subject matter.
In operation, pump 152 draws wash fluid in from sump 138 and pumps it to a diverter assembly 156, e.g., which is positioned within sump 138 of dishwasher appliance. Diverter assembly 156 may include a diverter disk (not shown) disposed within a diverter chamber 158 for selectively distributing the wash fluid to the spray arm assemblies 134, 140, 142 and/or other spray manifolds or devices. For example, the diverter disk may have a plurality of apertures that are configured to align with one or more outlet ports (not shown) at the top of diverter chamber 158. In this manner, the diverter disk may be selectively rotated to provide wash fluid to the desired spray device.
According to an exemplary embodiment, diverter assembly 156 is configured for selectively distributing the flow of wash fluid from pump 152 to various fluid supply conduits, only some of which are illustrated in
The dishwasher 100 is further equipped with a controller 160 to regulate operation of the dishwasher 100. The controller 160 may include one or more memory devices and one or more microprocessors, such as general or special purpose microprocessors operable to execute programming instructions or micro-control code associated with a cleaning cycle. The memory may represent random access memory such as DRAM, or read only memory such as ROM or FLASH. In one embodiment, the processor executes programming instructions stored in memory. The memory may be a separate component from the processor or may be included onboard within the processor. Alternatively, controller 160 may be constructed without using a microprocessor, e.g., using a combination of discrete analog and/or digital logic circuitry (such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like) to perform control functionality instead of relying upon software.
The controller 160 may be positioned in a variety of locations throughout dishwasher 100. In the illustrated embodiment, the controller 160 may be located within a control panel area 162 of door 116 as shown in
It should be appreciated that the invention is not limited to any particular style, model, or configuration of dishwasher 100. The exemplary embodiment depicted in
Referring now generally to
According to an example embodiment, drive motor 170 may be a variable speed motor. In this regard, drive motor 170 may be operated at various speeds depending on the current operating cycle of the dishwasher. For example, according to an exemplary embodiment, drive motor 170 may be configured to operate at any speed between a minimum speed, e.g., 1500 revolutions per minute (RPM), to a maximum rated speed, e.g., 4500 RPM. In this manner, use of a variable speed drive motor 170 enables efficient operation of dishwasher 100 in any operating mode. Thus, for example, the drain cycle may require a lower rotational speed than a wash cycle and/or rinse cycle. A variable speed drive motor 170 allows impeller rotation at the desired speeds while minimizing energy usage and unnecessary noise when drive motor 170 does not need to operate at full speed.
According to an exemplary embodiment, drive motor 170 and all its components may be potted. In this manner, drive motor 170 may be shock-resistant, submersible, and generally more reliable. Notably, because drive motor 170 is mounted inside wash chamber 106 and is completely submersible, no seals are required and the likelihood of leaks is reduced. In addition, because drive motor 170 is mounted in the normally unused space between lower spray arm assembly 134 and a bottom wall of sump 138, instead of beneath the sump 138, this design is inherently more compact than conventional designs.
According to an exemplary embodiment, fluid circulation assembly 150 may be vertically mounted within sump 138 of wash chamber 106. More particularly, drive motor 170 of fluid circulation assembly 150 may be mounted such that drive shaft 176 is oriented along vertical direction V of dishwasher 100. More particularly, drive shaft 176 may define an axial direction A, a radial direction R, and a circumferential direction C (
Referring now to
Referring still to
As shown, diverter assembly 190 may include a diverter disc 192 disposed within a diverter chamber 194 (such as diverter chamber 158). Diverter chamber 194 is fluidly coupled to supply conduit 188, such that rotating diverter disc 192 may selectively distribute the flow of wash fluid to the spray arm assemblies 134, 140, 142, or any other fluid conduit coupled to diverter chamber 194. More particularly, diverter disc 192 may be rotatably mounted about the vertical direction V. Diverter disc 192 may have a plurality of apertures that are configured to align with a one or more outlet ports at the top of diverter chamber 194. In this manner, diverter disc 192 may be selectively rotated to provide wash fluid to spray arm assemblies 134, 140, 142 or other spray assemblies.
As illustrated in
As illustrated, filter 196 is a cylindrical and conical fine mesh filter constructed from a perforated stainless steel plate. Filter 196 may include a plurality of perforated holes, e.g., approximately 15/1000 of an inch in diameter, such that wash fluid may pass through filter 196, but food particles entrained in the wash fluid do not pass through filter 196. However, according to alternative embodiments, filter 196 may be any structure suitable for filtering food particles from wash fluid passing through filter 196. For example, filter 196 may be constructed from any suitably rigid material, may be formed into any suitable shape, and may include apertures of any suitable size for capturing particulates.
According to the illustrated exemplary embodiment, filter 196 defines an aperture through which drive shaft 176 extends. Wash pump impeller 182 is coupled to drive shaft 176 above filter 196 and a drain pump assembly (e.g., as described below) is coupled to drive shaft 176 below filter 196 along the vertical direction V. Fluid circulation assembly 150 may further include an inlet guide assembly 199 which is configured for accurately locating and securing filter 196 while allowing drive shaft 176 to pass through aperture and minimizing leaks between the filtered and unfiltered regions 197, 198 of sump 138. More specifically, as best illustrated in
Referring again to
Notably, drain pump impeller 202 is coupled to the bottom portion of drive shaft 176 using a one-way clutch 208. In this regard, during a wash/rinse cycle, drive motor 170 rotates in one direction, pumping filtered wash fluid using wash pump impeller 182. However, one-way clutch 208 is disengaged, so drain pump impeller 202 does not rotate at the same speed. Instead, drain pump impeller 202 may rotate at a decreased speed, e.g., due to some friction between one-way clutch 208 and drive shaft 176. According to alternative embodiments, drain pump impeller 202 may remain stationary during the wash cycle or may rotate at the same speed as wash pump impeller 182. In both cases, soil and food particles will have a tendency to collect within drain volute 204, as described herein. By contrast, during a drain cycle, drive motor 170 rotates in the opposite direction, thereby engaging one-way clutch 208 and causing drain pump impeller 202 to rotate and discharge wash fluid.
Referring now specifically to
As shown, 220 may generally define an axial direction A, a radial direction R, and a circumferential direction C that correspond to the same directions defined by drive shaft 176 when installed in wash pump assembly 180. Wash pump impeller 182, or more specifically hub 220, may define a receiving boss 224 that is configured for receiving drive shaft 176. In this regard, receiving boss 224 may be integrally formed with hub 220 and vanes 222. Moreover, receiving boss 224 may define a keyed or complementary profile for engaging drive shaft 176 to rotatably fix hub 220 to drive shaft 176. In addition, receiving boss 224 may define one or more apertures (not shown) for receiving a cotter pin, a set screw, or another suitable securing means for coupling wash pump impeller 182 to drive shaft 176.
According to the illustrated embodiment, hub 220 defines a flow surface 226 that is positioned on opposite receiving boss 224. Vanes 222 extend from flow surface 226 into sump 138, such that they are exposed to wash fluid therein. In this manner, when drive motor 170 rotates drive shaft 176, wash pump impeller 182 is configured for urging a flow of wash fluid into wash chamber 106 for cleaning articles positioned therein. As best shown in
In addition, according to exemplary embodiments of the present subject matter, hub 220 may have any suitable size for urging a flow of wash fluid within dishwasher appliance 100. For example, hub 220 may define a hub diameter 234 which is measured in a radial plane defined by the radial direction R (e.g., a plane defined perpendicular to the axial direction A). In addition, hub 220 may define a hub height 236 defined along the axial direction A. According to exemplary embodiments, the hub diameter 234 is less than 10 inches, less than 5 inches, or even smaller. In addition, hub height 236 may be approximately half of hub diameter 234, e.g. such as between 1 and 3 inches. It should be appreciated that these values are only exemplary and are not intended to limit the scope of the present subject matter. Thus, the contour of hub 220 shown herein could instead have any other suitable shape according to alternative embodiments.
Referring again generally to
As best shown in
Notably, in addition to extending at angles other than 90 degrees from hub 220, vanes 222 may generally be curved within three dimensions. More specifically, vanes may be curved within a radial plane defined perpendicular to the axial direction A, e.g., similar to conventional two-dimensional radial impellers. However, vanes 222 may also sweep backwards over and adjacent vane 222 for improved flow characteristics. Notably, as explained briefly above, vanes 222 may typically not be formed using conventional manufacturing techniques such as injection molding and machining because sliding elements of an injection molding machine must be removed or a machining tool must be able to access the back side of each vane 222, which is typically not possible for the vane geometries described herein.
Referring now specifically to
In general, the exemplary embodiments of wash pump impeller 182 described herein may be manufactured or formed using any suitable process. However, in accordance with several aspects of the present subject matter, wash pump impeller 182 may be formed using an additive manufacturing process, such as a 3-D printing process. The use of such a process may allow wash pump impeller 182 to be formed integrally, as a single monolithic component, or as any suitable number of sub-components. In particular, the manufacturing process may allow wash pump impeller 182 to be integrally formed and include a variety of features and geometries not possible when using prior manufacturing methods. Some of these novel features are described herein.
As used herein, the terms “additively manufactured” or “additive manufacturing techniques or processes” refer generally to manufacturing processes wherein successive layers of material(s) are provided on each other to “build-up,” layer-by-layer, a three-dimensional component. The successive layers generally fuse together to form a monolithic component which may have a variety of integral sub-components. Although additive manufacturing technology is described herein as enabling fabrication of complex objects by building objects point-by-point, layer-by-layer, typically in a vertical direction, other methods of fabrication are possible and within the scope of the present subject matter. For example, although the discussion herein refers to the addition of material to form successive layers, one skilled in the art will appreciate that the methods and structures disclosed herein may be practiced with any additive manufacturing technique or manufacturing technology. For example, embodiments of the present invention may use layer-additive processes, layer-subtractive processes, or hybrid processes.
Suitable additive manufacturing techniques in accordance with the present disclosure include, for example, Fused Deposition Modeling (FDM), Selective Laser Sintering (SLS), 3D printing such as by inkjets and laserjets, Sterolithography (SLA),
Direct Selective Laser Sintering (DSLS), Electron Beam Sintering (EBS), Electron Beam Melting (EBM), Laser Engineered Net Shaping (LENS), Laser Net Shape Manufacturing (LNSM), Direct Metal Deposition (DMD), Digital Light Processing (DLP), Direct Selective Laser Melting (DSLM), Selective Laser Melting (SLM), Direct Metal Laser Melting (DMLM), and other known processes.
In addition to using a direct metal laser sintering (DMLS) or direct metal laser melting (DMLM) process where an energy source is used to selectively sinter or melt portions of a layer of powder, it should be appreciated that according to alternative embodiments, the additive manufacturing process may be a “binder jetting” process. In this regard, binder jetting involves successively depositing layers of additive powder in a similar manner as described above. However, instead of using an energy source to generate an energy beam to selectively melt or fuse the additive powders, binder jetting involves selectively depositing a liquid binding agent onto each layer of powder. The liquid binding agent may be, for example, a photo-curable polymer or another liquid bonding agent. Other suitable additive manufacturing methods and variants are intended to be within the scope of the present subject matter.
The additive manufacturing processes described herein may be used for forming components using any suitable material. For example, the material may be plastic, metal, concrete, ceramic, polymer, epoxy, photopolymer resin, or any other suitable material that may be in solid, liquid, powder, sheet material, wire, or any other suitable form. In addition, according to exemplary embodiments of the present subject matter, the additively manufactured components described herein may be formed in part, in whole, or in some combination of any or all of the materials described above, as well as with other known materials. These materials are examples of materials suitable for use in the additive manufacturing processes described herein, and may be generally referred to as “additive materials.”
In addition, one skilled in the art will appreciate that a variety of materials and methods for bonding those materials may be used and are contemplated as within the scope of the present disclosure. As used herein, references to “fusing” may refer to any suitable process for creating a bonded layer of any of the above materials. For example, if an object is made from polymer, fusing may refer to creating a thermoset bond between polymer materials. If the object is epoxy, the bond may be formed by a crosslinking process. If the material is ceramic, the bond may be formed by a sintering process. If the material is powdered metal, the bond may be formed by a melting or sintering process. One skilled in the art will appreciate that other methods of fusing materials to make a component by additive manufacturing are possible, and the presently disclosed subject matter may be practiced with those methods.
In addition, the additive manufacturing process disclosed herein allows a single component to be formed from multiple materials. Thus, the components described herein may be formed from any suitable mixtures of the above materials. For example, a component may include multiple layers, segments, or parts that are formed using different materials, processes, and/or on different additive manufacturing machines. In this manner, components may be constructed which have different materials and material properties for meeting the demands of any particular application. In addition, although the components described herein are constructed entirely by additive manufacturing processes, it should be appreciated that in alternate embodiments, all or a portion of these components may be formed via casting, machining, and/or any other suitable manufacturing process. Indeed, any suitable combination of materials and manufacturing methods may be used to form these components.
An exemplary additive manufacturing process will now be described. Additive manufacturing processes fabricate components using three-dimensional (3D) information, for example a three-dimensional computer model, of the component. Accordingly, a three-dimensional design model of the component may be defined prior to manufacturing. In this regard, a model or prototype of the component may be scanned to determine the three-dimensional information of the component. As another example, a model of the component may be constructed using a suitable computer aided design (CAD) program to define the three-dimensional design model of the component.
The design model may include 3D numeric coordinates of the entire configuration of the component including both external and internal surfaces of the component. For example, the design model may define the body, the surface, and/or internal passageways such as openings, support structures, etc. In one exemplary embodiment, the three-dimensional design model is converted into a plurality of slices or segments, e.g., along a central (e.g., vertical) axis of the component or any other suitable axis. Each slice may define a thin cross section of the component for a predetermined height of the slice. The plurality of successive cross-sectional slices together form the 3D component. The component is then “built-up” slice-by-slice, or layer-by-layer, until finished.
In this manner, the components described herein may be fabricated using the additive process, or more specifically each layer is successively formed, e.g., by fusing or polymerizing a plastic using laser energy or heat or by sintering or melting metal powder. For example, a particular type of additive manufacturing process may use an energy beam, for example, an electron beam or electromagnetic radiation such as a laser beam, to sinter or melt a powder material. Any suitable laser and laser parameters may be used, including considerations with respect to power, laser beam spot size, and scanning velocity. The build material may be formed by any suitable powder or material selected for enhanced strength, durability, and useful life.
Each successive layer may be, for example, between about 10 μm and 200 μm, although the thickness may be selected based on any number of parameters and may be any suitable size according to alternative embodiments. Therefore, utilizing the additive formation methods described above, the components described herein may have cross sections as thin as one thickness of an associated powder layer, e.g., 10 μm, utilized during the additive formation process.
In addition, utilizing an additive process, the surface finish and features of the components may vary as need depending on the application. For example, the surface finish may be adjusted (e.g., made smoother or rougher) by selecting appropriate laser scan parameters (e.g., laser power, scan speed, laser focal spot size, etc.) during the additive process, especially in the periphery of a cross-sectional layer which corresponds to the part surface. For example, a rougher finish may be achieved by increasing laser scan speed or decreasing the size of the melt pool formed, and a smoother finish may be achieved by decreasing laser scan speed or increasing the size of the melt pool formed. The scanning pattern and/or laser power can also be changed to change the surface finish in a selected area.
Notably, in exemplary embodiments, several features of the components described herein were previously not possible due to manufacturing restraints. However, the present inventors have advantageously utilized current advances in additive manufacturing techniques to develop exemplary embodiments of such components generally in accordance with the present disclosure. While the present disclosure is not limited to the use of additive manufacturing to form these components generally, additive manufacturing does provide a variety of manufacturing advantages, including ease of manufacturing, reduced cost, greater accuracy, etc.
In this regard, utilizing additive manufacturing methods, even multi-part components may be formed as a single piece of continuous material, and may thus include fewer sub-components and/or joints compared to prior designs. The integral formation of these multi-part components through additive manufacturing may advantageously improve the overall assembly process. For example, the integral formation reduces the number of separate parts that must be assembled, thus reducing associated time and overall assembly costs. Additionally, existing issues with, for example, leakage, joint quality between separate parts, and overall performance may advantageously be reduced.
Also, the additive manufacturing methods described above enable much more complex and intricate shapes and contours of the components described herein. For example, such components may include thin additively manufactured layers and unique features or geometries. In addition, the additive manufacturing process enables the manufacture of a single component having different materials such that different portions of the component may exhibit different performance characteristics. The successive, additive nature of the manufacturing process enables the construction of these novel features. As a result, the components described herein may exhibit improved performance and reliability.
Now that the construction and configuration of dishwasher appliance 100 and wash pump impeller 182 have been described according to exemplary embodiments of the present subject matter, an exemplary method 300 for manufacturing a wash pump impeller for a dishwasher will be described according to an exemplary embodiment of the present subject matter. Method 300 can be used to additively manufacture wash pump impeller 182 of dishwasher appliance 100, or any other suitable impeller. It should be appreciated that the exemplary method 300 is discussed herein only to describe exemplary aspects of the present subject matter, and is not intended to be limiting.
Referring now to
Step 330 includes fabricating the wash pump impeller using an additive manufacturing process. In this regard, step 330 includes successively forming each cross-sectional layer of the wash pump impeller with an additive manufacturing process, e.g., by repeatedly depositing layers of additive powder and selectively fusing those layers as desired to form the wash pump impeller having the desired geometry or three-dimensional shape defined by the model. The wash pump impeller may be formed using any suitable additive manufacturing process, examples of which are provided above.
The wash pump impeller described above achieves a very high a level of hydraulic efficiency, particularly relative to conventional wash pump impellers. In this manner, the wash pump impeller may be smaller and use a smaller motor while achieving the same pump performance, e.g., in terms of pressure head and flow rates achieved. Moreover, the resulting wash pump assembly and dishwasher appliance are quieter, more energy efficient, and more economical to produce (e.g., due in part to less acoustical insulation). These wash pump impellers may further be designed to meet the needs of any specific application to achieve significant hydraulic efficiency improvements, e.g., 5% to 20% improvements in hydraulic efficiency.
Ideally the wash pump impeller construction chosen for a particular pump is largely based on a combination of: the rotational speed, flow rate, and total pressure head (i.e., the sum of the dynamic and static heads) of the wash pump assembly. According to exemplary embodiment, the most efficient impeller for a dishwasher appliance is referred to as a “mixed flow” impeller, which typically has a complex three-dimensional vane shape that is difficult if not impossible to produce by injection molding or must include so few vanes (to avoid manufacturing problems) that the efficiency gains from having optimally formed vanes is lost. However, additive manufacturing permits designing an optimized impeller geometry, establishing three-dimensional information defining that geometry (in the form of a solid model for instance), converting the three-dimensional information into a plurality of slices and then finally successively forming each cross-sectional layer of the mixed-flow impeller with three-dimensional vanes.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.