Additive manufacturing methods for components

A method of forming a unitary sintered body can include cutting a first portion and a second portion from a sheet of feedstock. The feedstock can include ceramic or metallic particles suspended in a binder. The first portion can be positioned in contact with the second portion and the portions can be sintered together to form the unitary body.

FIELD

The described embodiments relate generally to electronic device components formed using additive manufacturing processes. More particularly, the present examples relate to layered metal components.

BACKGROUND

Electronic devices are widespread in society and can take a variety of forms, from wristwatches to computers. Electronic devices, including portable electronic devices such as handheld phones, tablet computers, and watches generally include a type of housing or enclosure to house the internal components.

The manufacturing of such enclosures or housings, can benefit from increased output, reduced material waste, and reduced machining requirements. Thus, it can be desirable to produce a device enclosure using additive manufacturing processes to reduce material waste and machining costs and increase output.

Further, such enclosures or housings can benefit from a combination of multiple materials that form the component. The combination of multiple materials in complex design configurations can introduce complications into traditional manufacturing processes. For example, device enclosures formed of multiple materials can require increased processing time, material, and cost when manufactured using traditional techniques. In some examples, common manufacturing processes may not be able to produce a device enclosure with a desired combination of properties. Accordingly, it can be desirable to provide processing and manufacturing techniques that allow for efficient, low cost, and low waste production of device enclosures having a desired combination of differing properties.

SUMMARY

According to some aspects of the present disclosure, a unitary body can include a sintered metal that defines an enclosed cavity having a volume of between about 1 cm3to about 10,000 cm3.

In some examples, the sintered metal includes a first layer bonded to a second layer at an interface including a striated microstructure. The first layer includes an outer portion and an inner portion, the outer portion having a higher density than the inner portion. The sintered metal includes a first region having a first density and a second region having a second density different from the first density. The unitary body can further include a residual binder, the unitary body including between about 0.001% and about 70% residual binder by weight. The sintered metal includes a sidewall and a floor that define the enclosed cavity, the sidewalls having an angle relative to the floor of greater than about 20°. The sintered metal includes at least one of aluminum, steel, or titanium.

According to some aspects, a method of forming a unitary body can include removing at least one of a first portion and a second portion from a feedstock including particles suspended in a binder, positioning the first portion in contact with the second portion, and sintering the first portion and the second portion to form the unitary body.

In some examples, the method can further include positioning a third portion in contact with the second portion, the third portion cut from the feedstock and defining an aperture. In other examples, the method can include positioning a third portion that includes a second material in contact with the first portion such that the first portion is disposed between the second portion and the third portion. The first portion can include an adherent between the second portion and the third portion prior to sintering. The unitary body defines an enclosed cavity. The first portion includes first particles and the second portion includes second particles, the first particles including a different material than the second particles. The method can further include positioning a component in a volume defined by the unitary body. The feedstock includes between about 0% and about 70% of the binder by weight. Removing at least one of the first portion and the second portion from the feedstock can include laser cutting at least one of the first portion and the second portion from the feedstock. Laser cutting at least one of the first portion and the second portion from the feedstock can include cutting at least one of the first portion and the second portion in a desired shape with a dimensional tolerance of less than about 10 microns. Sintering the first portion and the second portion to form the unitary body can include heating the first portion and the second portion to a temperature of at least about 500° C. The method can further include debinding the first portion and the second portion.

According to some aspects, a metallic part can include a unitary sintered body having a density greater than about 95%, the unitary sintered body including a first layer fused to a second layer along a planar interface region including a striated microstructure. In some examples, the unitary sintered body includes steel. The unitary sintered body includes a first metal and a second metal different from the first metal.

DETAILED DESCRIPTION

One aspect of the present disclosure relates to a method for forming unitary sintered parts, such as unitary sintered metallic parts for electronic devices. A method for forming a metallic part, such as a housing component for an electronic device, can include forming a feedstock material including a polymer binder and metallic particles. Multiple pieces or portions can be removed from the feedstock material by laser cutting or stamping. The pieces can be removed in a desired shape, for example, a shape corresponding to a cross-sectional layer of the part to be formed, with high dimensional precision. The pieces can be assembled in a desired arrangement

Additive manufacturing, also referred to as 3D printing, can be refer to processes to form 3-dimensional components by depositing material over a substrate or other portion of material. The materials used in additive manufacturing processes can include metals, plastics, ceramics, and composite materials. Conventional techniques for 3D printing can involve selectively depositing or printing a mixture of a binder material and a powder onto a substrate or a platform. This green part can then be drawn or built up, layer by layer, into a desired shape, after which the binder can be burned off and the powder can be sintered or fused together.

Conventional 3D printing techniques that rely on a print head to draw layers of material can form a wide variety of shapes and geometries, but can also be limited in certain aspects. For example, relatively large unsupported spans can be difficult or impossible to produce because many of the drawn layers are unsupported until the complete structure has been drawn, leading them to collapse under their own weight. Examples of such geometries include bridge structures or hollow box structures. As used herein, the term hollow box can refer to any geometry that has a cavity or defines a volume that is completely enclosed by material without supports disposed within the cavity or volume.

In contrast, the additive manufacturing processes described herein can produce substantially any geometry or structure as desired, including structures having relatively large unsupported spans and/or fully enclosed cavities or volumes. By removing portions of material from a block or sheet of feedstock including a binder and a powder, and positioning the portions adjacent one another to form a part, these typically difficult to print structures can easily be formed. This can be because each layer of material can be removed from the feedstock as a single self-supporting piece and then positioned at a desired location on the part, rather than being formed, in a non-self-supporting manner at the desired location. While some conventional techniques, such as binder jet 3D printing, can produce relatively large unsupported spas having a bridge geometry, these techniques are typically incapable of also producing an enclosed hollow box geometry.

The additive manufacturing processes described herein can also produce components and parts that have highly precise shapes, with resolutions in the range of several microns. Whereas conventional 3D printing techniques can be dimensionally limited by the size of the print head and the stream of binder and powder being deposited, the processes described herein can include high-precisions techniques such as stamping or laser-cutting to form portions from a feedstock. The ability to form entire layers or portions from a feedstock can also result in a reduction in manufacturing time, because there is no need for a print head to traverse the entire area of each layer of a part. Additionally, the additive manufacturing processes described herein can produce parts and components that include multiple materials and/or multiple densities or forms of a single material because different feedstocks can be used to form various portions of the part as desired.

FIG.1shows an example of an electronic device100. The electronic device shown inFIG.1is a watch, such as a smartwatch. The smartwatch ofFIG.1is merely one representative example of a device that can be used in conjunction with the components and methods disclosed herein. The electronic device100can correspond to any form of a wearable electronic device, a portable media player, a media storage device, a portable digital assistant (“PDA”), a tablet computer, a computer, a mobile communication device, a GPS unit, a remote control device, and the like. The electronic device100can be referred to as an electronic device, a device, or a consumer device. Further details of the electronic device100are provided below with reference toFIGS.2and3A.

Referring now toFIG.2, the electronic device100includes a main housing or enclosure102. The housing or enclosure102can be connected to a front cover116and can have a strap150attached thereto. A number of input elements, such as a rotatable crown144and/or a button142can be attached to and protrude from the housing102. The housing102can substantially define at least a portion of an exterior surface of the device100. The cover116can include glass, plastic, ceramic, or any other substantially transparent material, component, or assembly. The cover116can cover or otherwise overlay a display, a camera, a touch sensitive surface, such as a touchscreen, or other component of the device100. The cover116can define a front exterior surface of the device100. A back cover130can also be attached to the housing102, for example, opposite the cover116. The back cover130can include ceramic, plastic, metal, or combinations thereof. In some examples, the back cover130can include an electromagnetically transparent portion132. The electromagnetically transparent portion132can be transparent to any wavelength of electromagnetic radiation, such as visual light, infrared light, radio waves, or combinations thereof. Together, the housing102, cover116, and back cover130can substantially define an interior volume and exterior surface of the device100. In some examples, the housing102defines at least a portion of the back cover130, such that the back cover130and housing102are integrally formed. The housing102can be formed from a metallic material. As discussed in greater detail below, the housing102can be formed using an additive manufacturing process, such as direct metal deposition. In some examples, the housing102can also include a surface layer formed by a physical vapor deposition process.

The housing102can be a substantially continuous or unitary component and can include one or more openings104,106to receive components, such as components142and144of the electronic device100and/or provide access to an internal portion of the electronic device100. Additionally, other components of the electronic device100, can be formed from or can include a metallic or ceramic material formed using the methods and techniques described herein.

The device100can also include internal components, such as a haptic engine124, a battery122, and a system in package (SiP), including one or more integrated circuits126, such as processors, sensors, and memory. The SiP can also include a package. All or a portion of one or more internal components can be contained within the internal volume defined by the housing102.

The internal components, such as one or more of components122,124,126can be disposed within an internal volume defined at least partially by the housing102, and can be affixed to the housing102via internal surfaces, attachment features, threaded connectors, studs, posts, or other features, that are formed into, defined by, or otherwise part of the housing102and/or the cover116or back cover130. In some examples, the attachment features can be formed relatively easily on interior surfaces of the housing102, for example, by machining. In some examples, the attachment features can be formed during the additive manufacturing process, as described herein.

The housing102formed from a metallic material can be conformable to interior dimensional requirements, as defined by the internal components122,124,126. For example, the structure of the housing102can be defined or limited exclusively or primarily by the internal components the housing102is designed to accommodate. That is, the housing102can be shaped to house the interior components122,124,126in a dimensionally efficient manner without being constrained by factors other than the dimensions of the components, such as conventional manufacturing limitations.

Any number or variety of parts or components, for example, components of an electronic device, can be formed from according to the processes described herein and can include the structures as described herein. The structure and materials of the parts and components, as well as the components themselves, can apply not only to the specific examples discussed herein, but to any number or variety of examples in any combination. Various examples of components formed by the additive manufacturing processes described herein are described below with reference toFIGS.3A-3D.

Referring now toFIG.3A, a perspective view of the housing102of the electronic device100is shown. The housing102can include a metal or ceramic structure that is partially or entirely formed using the additive manufacturing processes described herein. The illustration ofFIG.3Acan be representative of the shape and design of the structure immediately after formation using the processes described herein, or can represent a finalized housing that has undergone additional processing, such as machining.The housing102can also include features, such as speaker ports, button apertures, or charging ports apertures. As shown, apertures104,106, can be integrally formed in the housing102. In some examples, protruding features108can also be integrally formed in the housing102by the processes described herein. The features108can be support structures that can engage with fasteners or other components when assembling the electronic device while features104and106can be configured to receive buttons or inputs of the electronic device. As discussed in greater detail below, the housing102can be formed or machined to define the features.

FIG.3Bshows a cross-sectional view of a housing component202that can be substantially similar to, and include some or all of the features of the housing102shown inFIG.3A. The housing202can be formed by an additive manufacturing process as described herein and, as can be see, can have a hollow box geometry, including a cavity or volume216that is defined by at least an outer wall212and an inner wall214. In some examples, the outer wall212can also at least partially define the exterior surface of the housing202and an associated electronic device, while the inner wall214can at least partially define an internal volume of the electronic device. In some examples, one or more features218can be formed within the cavity216as desired. These features218can be attachment or support features for other components, can provide thermal management to the device, or can have any function or geometry as desired.

Additionally, in some examples, the geometry of the housing202defining a cavity216including a feature218therein may not be able to be achieved by conventional manufacturing processes. In some examples, and as described further herein, the cavity216can be formed by forming a green part according to the processes described herein that includes portions of binder material that do not include any powder at the location of the cavity216. When the green part is then subjected to debinding and/or sintering, as described herein, substantially no binder or other material will remain in the cavity while the powder is sintered or fused to form the sidewalls212,214.

FIG.3Cshows cross-sectional view of the housing component202shown inFIG.3Bincluding an operational component220disposed in the cavity216and affixed to the feature218. The operational component220can be affixed to the feature218by any technique as desired, such as an adhesive, fixture, and/or mechanical interlock. The operational component220can include any type or combination of computing component, digital component, or mechanical component as desired. For example, the operational component220can include one or more sensors or an inductive charging component. By providing a space for the positioning of the component220within the housing202itself, the geometry of the housing202defining the cavity216can allow for a device to include additional components or functionalities without the need to take up space within the internal volume of the device itself. This configuration can thereby allow for reduced device sizes and/or increased levels of performance or functionality. Further, in the example of an inductive charging component220, the position of the component220near the exterior surface defined by the outer wall212can further allow for increased performance.

In some examples, the housing202can define an aperture or opening in communication with the cavity216to allow the insertion or positioning of the operational component220at a desired location. In some examples, such as when the component220includes a structural or mechanical component, the housing202or portions thereof can be formed around the component220by the processes described herein. Further details regarding the structure of components formed according to the processes described herein are discussed with respect toFIG.3D.

FIG.3Dshows a cross-sectional view of a housing302that can be substantially similar to, and include some or all of the features of the housing102shown inFIG.3A. The housing302can include a unitary body or part, but as shown, the housing302can include multiple different materials, such as multiple different metals and/or ceramics. For example, the housing302can include one or more exterior portions312that are fused or bonded to one or more interior portions316,317. In some examples the exterior portion312can include a first metal, such as steel, while the interior portions316,317can include a second, different metal, such as aluminum.

The ability to select different materials to form various portions of a component, such as the housing302, can allow for advantageous combinations of the properties of several materials. For example, configurations where the exterior portion312includes steel and the interior portions316,317include aluminum can allow for a housing302that has a relatively hard and durable exterior surface material, while having a relatively lightweight and easily machinable interior surface.

In some examples, both the exterior portion312and the interior portions316,317can be formed as a unitary body according to the processes described herein. In some examples, however, one or more of the exterior portion312and/or interior portions316,317can be pre-formed by another process and the other of the portions can be formed and fused to the pre-formed portion according to the processes described herein.

The housing302is not limited to having a two-part construction, however, and different portions including different materials can have any geometry or arrangement as desired. For example, the housing302can include a feature313that can be formed according to the processes described herein and fused or bonded to the portion316, which can be pre-formed or formed concurrently with the feature313. The feature313can include a different material than the portion316to which it is fused. In some examples, the feature can be an attachment feature or support feature for components that are positioned in the internal volume defined by the housing302.

Additionally, or alternatively, the exterior portion312can include a protrusion314that can extend into or through the interior portions316,317. The protrusion314can be a support feature, attachment feature, or any other feature as desired. For example, the protrusion314can allow for controlled thermal communication between the exterior portion312and the internal volume of the housing302. Although a specific configuration is illustrated inFIG.3D, it will be understood that a component such as housing302can include any number of portions formed from any number of materials in any shape, size, and configuration.

Further, in some examples, the various portions of the housing302can include the same material, but can have different densities. For example, the exterior portion312can include a material, such as a metal or ceramic material, having a first density, while the interior portions316,317can include the same material having a second, different density. In some examples, the exterior portion312can have substantially any density described herein, such as a density of at least about 99%. In some examples, the interior portion316,317can also have substantially any density described herein, such as a density of less than about 80%. In some examples, the interior portions316,317can be considered a foam. Further, in some examples, the density of any of the portions of the housing302can vary across one or more dimensions of the portion. That is, any of the portions of the housing302can have a variable density at one or more regions, a stepped density between two or more regions, and/or a density gradient between two or more regions. In some examples, and as described further herein, the density of a component or part formed according to the processes described herein can be controlled by controlling the binder loading percentage of the feedstock used to form that portion of the component or part.

As used herein, the terms exterior, outer, interior, inner, front, rear, top, and bottom are used for reference purposes only. An exterior or outer portion of a component can form a portion of an exterior surface of the component but may not necessarily form the entire exterior of outer surface thereof. Similarly, the interior or inner portion of a component can form or define an interior or inner portion of the component but can also form or define a portion of an exterior or outer surface of the component. A top portion of a component can be located above a bottom portion in some orientations of the component, but can also be located in line with, below, or in other spatial relationships with the bottom portion depending on the orientation of the component.

Any number or variety of parts or components, for example, components of an electronic device, can be formed from according to the processes described herein and can include the structures as described herein. The structure and materials of the parts and components, as well as the components themselves, can apply not only to the specific examples discussed herein, but to any number or variety of examples in any combination. Various examples of components formed by the additive manufacturing processes described herein are described below with reference toFIGS.4-6.

FIG.4shows an example electronic device400that can have a housing or other components including the structures and formed according to the processes described herein. The electronic device100shown inFIG.4is a display or monitor, for example, as used with a computer. This is, however, merely one representative example of a device that can be used in conjunction with the ideas disclosed herein. The electronic device400can, for example, correspond to a portable media player, a media storage device, a portable digital assistant (“PDA”), a tablet computer, a computer, a mobile communication device, a GPS unit, a remote-control device, and the like. The electronic device400can be referred to as an electronic device, or a consumer device. Further details of the electronic device400are illustrated inFIG.5.

Referring now toFIG.5, the electronic device400can include a housing102and a cover403attached to the housing402. A number of internal components, such as a display assembly410, computing components, and other components can be disposed between the housing402and the cover403. The housing402can substantially define at least a portion of an exterior surface of the device400. The cover403can include glass, plastic, ceramic, or any other substantially transparent material, component, or assembly. The cover403can cover or otherwise overlay a display assembly410, a camera, a touch sensitive surface such as a touchscreen, and other components, of the device400. The cover403can define a front exterior surface of the device400. Together the housing402and the cover403can substantially define the exterior surface of the device400.

The device400can also include internal components, such as processors, memory, circuit boards, batteries, light emitting diodes (LEDs), fans, sensors, and other computing components. Such components can be disposed within an internal volume defined at least partially by the housing402and can be affixed to the housing402via internal surfaces, attachment features, threaded connectors, studs, posts, or the like, that are formed into, defined by, or otherwise part of the housing402and/or the cover403.

The housing402can be formed according to the additive manufacturing processes described herein, and as such can include unique or complicated geometries. For example, the housing402can include regions having a three-dimensional structure in order to allow for enhanced cooling performance, noise reduction, and/or aesthetics. The three-dimensional structure, such as a three-dimensional structure formed in regions of the housing402, can include a body having a first surface forming a portion of the exterior of the electronic device400and a second surface defining at least part of an internal volume of the housing402. Additionally, other components of the electronic device400, such as internal structural components, can be formed from or can include regions formed according to the processes described herein. In some examples, a housing402or other component can include a body with one or more cavities extending into the body from a first surface of a body and one or more cavities extending into the body from a second surface of the body. The one or more cavities extending into the body from the second surface of the body can intersect with or interfere with one or more cavities extending into the body from the first surface of the body to form a three-dimensional pattern of apertures or passageways in the body.

The body of a structure, for example, a contiguous structure formed according to the processes described herein, can include one or more structures formed in, defined by, or extending into the body from one or more of the surfaces of the body. For example, the body can have a generally cuboid shape, a generally spherical shape, a generally cylindrical shape, a generally toroidal shape, and the like. In some examples, the body can have a general shape of any polyhedron. In some other examples where the three-dimensional pattern extends through one or more regions of the body, the regions can be separated by one or more portions of the body that do not include the three-dimensional pattern. The one or more portions separating the regions of the body that include the three-dimensional pattern and can be substantially continuous. In some examples, however, the one or more portions can include structures or features formed in or on the one or more portions. As used herein, the term three-dimensional pattern can refer to a positive surface of a three-dimensional structure, or a negative space at least partially enclosed or defined by a surface or body. Further, the term enclosed is used herein to refer to a volume that is completely or entirely enclosed by a surface of body and does not comprise any pathways between the volume and an ambient environment external to the body. The three-dimensional pattern can include one or more irregular shapes, regular shapes, repeating shapes, or combinations thereof.

FIG.6illustrates a perspective view the housing402including a three-dimensional structure and formed according to the additive manufacturing processes described herein. The housing402can include a unitary body. The housing402can include at least a first surface404and a second surface406. In some example, the first surface404and the second surface406can be opposing surfaces of the housing402. For example, the first surface404can be parallel to and opposing the second surface406. In some examples, however, the first surface404and second surface406may not be substantially parallel or opposed and can be adjacent to each other or disposed relative to one another at any angle.

One or more first cavities408or recesses can extend into the housing402from the first surface404, while one or more second cavities414or recesses can extend into the housing402from the second surface406. The first and/or second cavities408,414can have substantially the same size and shape as one another, although in some example the first and/or second cavities408,414can vary in size and shape from one another. The first and/or second cavities408,414can have a substantially spherical or hemispherical shape, such that the negative space of a cavity408,414can have a shape of a portion or region of a sphere. In some other examples, however, the first and/or second cavities408,414can have any shape. As can be seen, the first and/or second cavities408,414can be arranged in a pattern, for example, a regular or repeating pattern of first and/or second cavities408,414. In some examples, the pattern can include a close-packed pattern of substantially spherical first and/or second cavities408,414, for example, a hexagonal close-packed pattern of substantially spherical cavities408,414. As used herein, a hexagonal close-packed pattern is intended to be understood as a structure that substantially corresponds to a layer of spheres or portions of spheres packed so that spheres or portions of spheres in alternating layers overlie one another, aligned in the gaps of the preceding layers. A traditional packing factor for hexagonal close packed systems is typically 0.74, though it can be higher in the present system due to the overlapping or interference pattern created. Further, as can be see, the regions of the housing402where the first and second cavities408,414extend into the body can be separated by a portion412of the body that does not include the three-dimensional pattern.

Any number or variety of parts or components, for example, components of an electronic device, can be formed from according to the processes described herein and can include the structures as described herein. The structure and materials of the parts and components, as well as the components themselves, can apply not only to the specific examples discussed herein, but to any number or variety of examples in any combination. Various examples of components formed by the additive manufacturing processes described herein are described below with reference toFIGS.7A-7D.

FIG.7Ashows a perspective view of a unitary body502including sintered metal and/or ceramic material and formed according to the additive manufacturing processes described herein. Although the body502is depicted as having a specific geometry, it will be understood that the unitary body502can have substantially any geometry desired. The body502can define an exterior surface504and can include one or more features506that can extend from the body502. In some examples, the feature506can be formed concurrently with the body502according to the processes described herein. In some examples, however, the body502can be formed prior to the feature506and the feature can be formed and joined to the pre-formed body502according to the processes described herein.

The body502can also define a cavity510or volume having a substantially hollow box geometry. That is, the body502can define a cavity510that can be completely, or substantially completely enclosed by the body502. The cavity510can be substantially uninterrupted by any features that provide support for those portions of the body502that define the cavity510. In some examples, the cavity510can be at least partially defined by a roof or other portion of the body502that spans a distance and is unsupported by other portions of the body502except for those portions that define the cavity510. In some examples, an angle of a sidewall defining the cavity510relative to the floor, roof, or other portion of the body502defining the cavity can be greater than about 15°, 20°, 30°, 40°, 45°, 50°, 60°, 70°, 80°, or greater than about 90° or more. In some examples, the cavity can define an enclosed volume of between about 1 cm3to about 10,000 cm3, between about 10 cm3to about 5,000 cm3, or between about 50 cm3and about 1000 cm3.

FIG.7Bshows a cross-sectional view of the unitary body502ofFIG.7A. As can be seen, the cavity510can be completely or substantially enclosed by the body502. The body502can be formed by sintering multiple portions or layers of a feedstock material having a desired geometry, as described herein. Accordingly, the cross-section shown inFIG.7Bcan correspond to the shape of a single such layer or portion. In some examples, the cavity510can thus be defined by several portions or layers of the body502, one or more of which can define an aperture or orifice. The alignment of several of these apertures or orifices defined by the layers of the body502can result in the formation of the cavity510, as described herein.

While the cavity510can be substantially empty or hollow, that is, the cavity510may not include any material of the body502, in some examples the cavity510can contain a component520disposed therein as shown in the cross-sectional view ofFIG.7C. In some examples, the component520can include a thermal component, mechanical component, and/or operational component. In some examples, the component520can include any type or combination of computing component, digital component, or mechanical component as desired. For example, the component520can include one or more sensors or an inductive charging component. In some examples, the body502can define an aperture or opening in communication with the cavity510to allow the insertion or positioning of the operational component520at a desired location. In some examples, however, the body502or portions thereof can be formed around the component520by the processes described herein. Thus, in some examples, the component520may not be directly connected to other operational components of an electronic device, but can instead include features to enable the component520to wirelessly receive data and/or power from a source or sources external to the cavity510. Further details of other configurations of a unitary body formed according to the processes described herein are illustrated with respect toFIG.7D.

FIG.7Dshows a cross-sectional view of the unitary body602that can be substantially similar to, and include some or all of the features of the unitary bodies described herein, such as the unitary body502ofFIG.7A. As with the body502, the unitary body602including sintered metal and/or ceramic material can define a cavity610. Further, in some examples, the body602can include multiple different materials, and/or materials having multiple different densities.

For example, the body602can include one or more exterior portions604that are fused or bonded to one or more interior portions605. In some examples the exterior portion604can include a first material, while the interior portions605can include a second, different material, and/or the first material having a second, different density and/or grain structure.

In some examples, both the exterior portion604and the interior portion605can be formed as a unitary body602according to the processes described herein. In some examples, however, one or more of the exterior portion605and/or interior portion604can be pre-formed by another process and the other of the portions can be formed and fused to the pre-formed portion according to the processes described herein. For example, the interior portion605can be pre-formed and include any material as desired, while the exterior portion604can include a sintered metal and/or ceramic material that can be formed and fused to the interior portion605according to the processes described herein. The body602is not limited to having a two-part construction, however, and different portions including different materials can have any number, geometry, or arrangement as desired.

Any number or variety of parts or components, for example, components of an electronic device, can be formed from according to the processes described herein and can include the structures as described herein. The structure and materials of the parts and components, as well as the components themselves, can apply not only to the specific examples discussed herein, but to any number or variety of examples in any combination. Various examples of additive manufacturing processes described herein are described below with reference toFIGS.8A-9E.

FIG.8Ashows a process flow diagram of a method700of forming a unitary body that can be substantially similar to, and include some or all of the features of the unitary bodies described herein. At block702, one or more portions or pieces can be removed from a feedstock including particles of a ceramic and/or metal material and a binder. At block704, the pieces can be positioned in contact with one another in a desired arrangement or geometry. At block706, the pieces can be sintered to remove substantially all of the binder therefrom, and to fuse or join the particles of the pieces into a unitary body including a sintered material or materials.

In some examples, the feedstock can include a polymer binder having a sinterable powder, or sinterable particles disposed or suspended therein. In some examples, the polymer binder can include one or more polymer materials.

In some examples, the sinterable particles can include any metallic and/or ceramic material as desired. In some examples, the sinterable particles can have an average major dimensions or diameter of between about 1 micron and about 200 microns, between about 5 microns and about 150 microns, between about 10 microns and about 100 microns, between about 20 microns and about 50 microns, or between about 20 microns and about 40 microns. In some examples, the particles can have a relatively uniform size distribution. That is, the particles can all have a substantially similar major dimension, for example, within about 5%, 10%, or 15% of the average major dimension of the particles. In some examples, however, the feedstock can include a variety of powder sizes, as desired. For example, the feedstock can include a first powder having a first average major dimension or range of major dimensions, and a second powder having a second, different average major dimension or range of major dimensions.

In some examples where the particles include a metal, the metal can include one or more of steel, aluminum, copper, titanium, and/or alloys thereof in any combination as desired. In some examples, where the particles include a ceramic, the ceramic can include sapphire, zirconia, or titania (titanium dioxide), in any combination as desired.

The feedstock can have substantially any shape as desired, and in some examples can include a sheet. Thus, in some examples, the one or more pieces can be removed from the feedstock sheet at block702. In some examples, multiple feedstocks can be used, such that a first piece can be removed from a first feedstock and a second piece can be removed from a second, different feedstock, for example, including a different binder and/or different particles than the first feedstock. In some examples, removing the one or more pieces from the feedstock at block702can be accomplished by any technique as desired. In some examples, removing a piece from the feedstock can be accomplished by cutting the piece from the feedstock, for example, with a blade, tool, laser, water jet, or any other technique. In some examples, removing a piece from the feedstock at block702can include laser cutting one or more pieces from the feedstock. In some examples, removing a piece from the feedstock at block702can include stamping one or more pieces using a stamping tool having a desired shape.

In some examples, the pieces can be removed from the feedstock at block702in a desired shape and having a dimensional tolerance of less than about 1 millimeter (mm), less than about 750 microns, less than about 500 microns, less than about 250 microns, less than about 200 microns, less than about 100 microns, less than about 50 microns, less than about 25 microns, less than about 10 microns, or less than about 5 microns, or smaller.

The pieces can then be positioned relative to one another in a desired configuration or arrangement to form a green body, for example, corresponding to a desired shape or geometry of the final part, at block704. In some examples, the pieces are positioned directly adjacent to or in direct contact with one another. In some examples, the pieces can be positioned in direct contact with other pieces or parts to which they will be fused or joined. For example, the one or more pieces removed from the feedstock can be positioned in contact with a pre-formed part to which they will be fused as described herein. In some examples, an adhesive or other material can be used to maintain the pieces in the desired configuration. In some examples, direct contact between the binder of the pieces can be sufficient to maintain the pieces in a desired arrangement as a green body. In some examples, pressure can be exerted on the pieces to reinforce or maintain the desired arrangement as a green body.

Once the pieces have been positioned relative to one another in the desired arrangement, the pieces can be sintered at block706to form a unitary body, such as the unitary bodies described herein. Sintering, at block706, can include heating the pieces to one or more desired temperatures for one or more desired durations. In some examples, the sintering process of block706can include a debinding step. That is, the pieces can be heated to volatilize and remove some or all of the binder including each piece. In some examples, the debinding step can be separate from a sintering process. In some examples, however, debinding can occur during a sintering process at block706.

In some examples, the sintering process can include heating the green body to a temperature of at least about 100° C., at least about 150° C., or at least about 200° C. or more for a desired duration. In some examples, the sintering process can include heating the green body to a temperature of at least about 300° C., at least about 350° C., at least about 400° C., at least about 450° C., at least about 500° C., or at least about 550° C. or more for a desired duration. In some examples, the sintering process can include heating the green body to a temperature of at least about 700° C., at least about 750° C., at least about 800° C., at least about 950° C., or at least about 1000° C. or more for a desired duration.

In some examples, the green body can be heated to a first temperature and held for a first duration, and then heated to one or more different temperatures and held for one or more durations as desired. Thus, in some examples, the sintering process of block706can include heating the green body to any combination of the temperatures described herein for any combination of durations. In some examples, heating the green body to a first temperature can remove a first portion of the binder, while heating the green body to a second, higher temperature can remove a second portion of the binder. In some examples, the first and second portions of the binder can include different polymers or components of the binder, such as components having different volatilization temperatures. In some examples, at least some of the binder can remain in the final sintered part even after the sintering process of block706. In some examples, the final sintered part can have between about 0% and about 70% residual binder, by weight; or between about 0.001% and about 70% residual binder, by weight.

The sintering process of block706can result in the sintering or fusion of the metal and/or ceramic particles of the green body joining together or fusing with one another to form a unitary body as described herein. In some examples, the sintering process of block706can further density of consolidate the material of the particles and densify the unitary body to a desired degree. For example, a sintered unitary body as described herein can have a density of at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, at least about 99%, or at least about 99.5% or more. In some examples, the sintered unitary body can be substantially 100% dense. Further, as described herein, one or more portions of the unitary body can have different densities as desired.

As used herein, the term density can refer to the percentage of the volume of the sintered part that is occupied by the material of the particles or powder of the green body. That is, the percentage of the volume of the unitary body that is not occupied by pores and/or open spaces between sintered particles. Accordingly, the density of the unitary body can also be equal to 100% minus the porosity percentage of the unitary body. For example, a unitary body having a density of 99% will also have a porosity of 1%.

In some examples, one or more stages of the sintering process of block706can be carried out in one or more different atmospheres as desired. In some examples, sintering in different atmospheres can affect different metal and/or ceramic materials of the green body in different ways. For example, sintering in an atmosphere including oxygen can result in different materials, such as different metal alloys, achieving different colors in the sintered unitary body. In some examples, one or more stages of the sintering process can be carried out in an atmosphere including oxygen, nitrogen, hydrogen, an inert gas such as argon, any gas as desired, or combinations thereof. In some examples, one or more stages of the sintering process can be carried out at a reduced pressure, such as in a vacuum.

FIG.8Bshows a cross-sectional view of a unitary body710including sintered metal and/or ceramic material and formed according to the additive manufacturing processes described herein. Specifically,FIG.8Bshows a unitary body710including a first layer712being a metal injection molding (MIM) layer. The MIM layer can include particles suspended in a binder. In some embodiments, a second layer714can also be a MIM layer. In other embodiments, the second layer714can include a layer of sheet metal or other material. In some examples, upon being joined together via sintering, as described above in reference toFIG.8A, a MIM layer such as first layer712can act as a brazing layer. The MIM layer can fuse the layers of a sintered unitary body together. In some examples, the layers can form a cohesive material.FIG.8Bshows an example where a microstructure of the first layer712differs from a microstructure of the second layer714. In some examples, the microstructures of the first layer712and the second layer714can include grain sizes that differ due to the different material history and/or composition of the layers, as well as possible impurities within the powder or binder of the MIM layer. For example, first layer712can include a MIM 316L layer and the second layer714can include an annealed 316Li sheet. After sintering, as described above, the first layer and the second layer can include differing grain structures, even though macroscopically and functionally the unitary body can be uniform. In some examples, the composition of the MIM layer can include a higher carbon content than a sheet metal. In some examples, differing MIM layers can include different material compositions.

FIG.8Cshows a cross-sectional view of a unitary body720including sintered metal and/or ceramic material formed according to the additive manufacturing processes described herein. In some examples, unitary body720can include multiple layers of material, for example layers722. In an example, layers722can be MIM layers. In some examples, when layers722are MIM layers, the unitary body can include a slot724. Slot724can include diameters of about 50 microns. In some examples, slot724can include ejection pinholes caused by manufacture processing. In some examples, layers726can include MIM layers. The MIM layers726can include an interface728between the layers that do not include slot724. In some examples, layers726can be a material such as a sheet metal, sintered metal, and/or ceramic material that is not a MIM layer. After sintering, the layers726can be uniform and cohesive such that no distinguishing structure or slot is included at the interface728.

FIG.8Dshows a cross-sectional view of a unitary body730. In some examples, the unitary body70can have a first layer732interface with a second layer734. The first layer732and the second layer734can include a first density and a second density, respectively. In some examples, the first density can be different from the second density. Similar to that described above with reference toFIG.3D, an exterior layer or portion can include a material, such as a metal or ceramic material, having a first density, while an interior portion can include the same material having a second, different density. In some examples, the second layer734can have substantially any density described herein, such as a density of at least about 99%. In some examples, the first layer732can also have substantially any density described herein, such as a density of less than about 80%. In some examples, the first layer732can be considered a foam and/or a metallic foam. Further, in some examples, the density of any of the layers of the unitary body730can vary across one or more dimensions of the body. That is, any of the layers of the unitary body730can have a variable density at one or more regions, a stepped density between two or more regions, and/or a density gradient between two or more regions. In an example, the first layer732can include a porous MIM layer.

In some examples, the first layer732as a porous MIM layer can be sintered onto another material, such as the second layer734. In some examples, the second layer734can include a MIM layer, a sheet metal, or other material. In some embodiments, the interface between the first layer732and the second layer734can be a gradient of densities and/or porosity. In other embodiments, the interface between the first layer732and the second layer734can be abrupt. For example, the density of the first layer732at the interface can be about 60% and the density of the second layer734at the interface can be about 99%. In some examples the porous MIM layer and/or unitary body730can include stainless steel structures, copper, titanium, aluminum, and/or other suitable metal.

In some examples, the density of the porous MIM layer can be controlled by the grain size of the powder prior to the sintering process. In other examples, the temperature of the sintering can be adjusted to control the density and/or porosity of the MIM layer and/or the unitary body730. In some examples, the density of the porous MIM layer can be controlled to improve polymer/resin bonding in selective areas. In other examples, the density of the porous MIM layer can be controlled to reduce weight of the unitary body730in specific desired areas. According to one example, the density of a single porous MIM layer can be selectively tuned to have selectively dense areas (such as those areas likely to be impacted during a drop event, or areas that may be placed under a load during use) and selectively less dense in other areas of the MIM layer to reduce overall weight and/or to enhance polymer binding.

FIG.8Eshows an exploded view of a component740of an electronic device. In some examples, the electronic device can include a boss column742and a boss column joint layer744. The boss column742can be sintered to the boss column joint layer744and a core layer746. The core layer746can be further sintered to a shell joint layer748and a cosmetic shell layer750in some examples. The core layer746and the cosmetic shell layer750can be a sheet metal. In some examples, the shell joint layer748can be a first material. In some examples, the first material can include a MIM layer or a material including particles suspended in a binder. In some examples, the first material can be positioned between and in contact with a second layer and a third layer, respectively. InFIG.8E, the second layer can include the core layer746and the third layer can include the cosmetic shell layer750. In some examples, the third layer can include a second material. The second material can include a sheet metal, a ceramic material, or another suitable material. In some examples, the third layer can be positioned in contact with the first layer such that the first layer is disposed between the second layer and the third layer. In such a configuration, in some examples, the first layer can act as an adherent layer between the second layer and the third layer prior to sintering. In other words, in manufacturing the component740, the shell joint layer748can act as an adhesive between the core layer746and the cosmetic shell layer750. The first layer, second layer, and third layer can be sintered together to form a unitary body. In an example, the boss column742, the boss column joint layer744, the core layer746, the shell joint layer748, and the cosmetic shell750can be sintered together to form the sintered assembly752. In other words, the first layer, second layer, and third layer can be sintered together to form the unitary body and/or component740of the electronic device.

Further details of processes for forming a sintered unitary body as described herein are illustrated with respect toFIGS.9A-9E.

FIG.9Ashows a feedstock801for use in a process of forming a unitary body, such as the process700. In some examples, the feedstock801can be formed by mixing or combining a binder with a powder or particles including metal and/or ceramic material as described herein. In some examples, the feedstock801can be formed into substantially any shape as desired, such as a block, sheet, or shape having a curved geometry. In some examples, the material can be pressed into a desired shape to form the feedstock801. In some examples, the material can be extruded into a desired shape to form the feedstock801. In some examples, multiple different feedstocks801can be formed, such as feedstocks801having different materials, particles sizes, and/or binder loading percentages.

FIG.9Bshows the feedstock801ofFIG.9Aafter having been pressed into a sheet shape. In some examples, this feedstock sheet801can have any thickness as desired. In some examples, the feedstock801can have a thickness of less than about 10 microns, less than about 5 microns, less than about 2 microns, less than about 1 micron, less than about 500 microns, less than about 250 microns, or less than about 200 microns or smaller. In some examples, the feedstock801can have a thickness of at least about 4 times, 5 times, 6 times, or 10 times, or more of the average major dimension of the particles including the feedstock.

As shown inFIG.9B, multiple portions or pieces812,814,816,818can be removed from a single portion of feedstock801as described herein. In some examples, however, one or more of the pieces812,814,816,818can be removed from a different feedstock, such as a feedstock including different materials, particles sizes, and/or binder loading percentages.

FIG.9Cthe pieces812,814,816,818after having been removed from the feedstock801. The pieces812,814,816,818can be removed by any of the processes described herein, such as a laser cutting and/or stamping process. As can be seen, one or more of the pieces812,814,816,818can define an aperture, orifice, notch, or other shape that when assembled into a desired configuration can define at least a portion of an unsupported span or cavity820as described herein.

The pieces812,814,816,818can be positioned relative to one another as shown by any desired process or technique, for example, an automated or robotically controlled process. As described herein, one or more of the pieces812,814,816,818can include different materials than one or more of the other pieces812,814,816,818. In some examples, the pieces812,814,816,818can be a bottom piece812, one or more middle pieces814,816, and a top piece818. Further, in some examples, one or more of the pieces812,814,816,818can include a pre-formed material, such as a portion of metal or ceramic that does not include the feedstock801. For example, the bottom piece812and/or top piece818can include a sheet of a metallic material that can be fused to the particles of the other pieces814,816during a sintering process as described herein.

FIG.9Dshows a perspective view of a unitary body802formed from the assembled pieces812,814,816,818of feedstock shown inFIG.9Cafter being subjected to a sintering process as described herein. The body802can be substantially similar to, and include some or all of the features of the unitary bodies described herein. In some examples, the body802can define an exterior surface832and can include one or more features834that can extend from the body802. The body802can also define a cavity820or volume having a substantially hollow box geometry. While the cavity820can be substantially empty or hollow, that is, the cavity820may not include any material of the body802, in some examples the cavity820can contain a component840disposed therein.

In some examples, the body802can be smaller in one or more dimensions as compared to the green body formed from the pieces812,814,816,818. This can occur as a result of the sintering process. In some examples, the body802can shrink or be smaller in one or more dimensions by about 20 microns to about 30 microns as comparted to the dimensions of the green body.

FIG.9Eshows a cross-sectional view of the microstructure of the unitary body802ofFIG.9D. As can be seen, even though the unitary body802can be substantially dense and the layers or pieces forming the green body can be fused or joined together, in some examples, the interfaces between the pieces of the green body can still be visualized or distinguished in the formed body802. For example, a piece812can be fused to the piece814along the interface813therebetween. Similarly, the pieces814can be fused to adjacent piece816along an interface815. In some examples, these interfaces813,815can be defined by differences in density, material, and/or grain structure between the adjacent layers even though the layers can be completely fused together, resulting in a striated microstructure.

In some examples, each layer or piece, such as piece816of the green body can result in a density and/or grain structure gradient in the unitary body802corresponding to the shape of the piece816. For example, the piece816can result in relatively more dense regions816-1and816-3corresponding to the exterior regions, such as the top and bottom, of the piece816. The piece816can also result in a relatively less dense region816-2corresponding to the interior region of the piece816. In some examples, an absolute difference in density between the regions816-1,816-3and the region816-2can be at least about 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 1%, 2%, or even at least about 5%.

Any of the features or aspects of the components, devices, and methods discussed herein can be combined or included in any varied combination. For example, any methods of forming a sintered unitary body for an electronic device can be used in combination to form any component as described herein. The steps, stages, or blocks of any of the methods described herein can be performed in any desired order and can be performed simultaneously if desired. Further, a component of a device can be formed from a sintered unitary body as described herein that can include one or more features formed therein. Any method can be used to form such a feature or features. Although certain methods and components are described with respect to housings, enclosures, or frames for electronic devices, the methods and components described herein can also be or form any number of additional components of an electronic device, including internal components, external components, cases, surfaces, or partial surfaces.

To the extent applicable to the present technology, gathering and use of data available from various sources can be used to improve the delivery to users of invitational content or any other content that may be of interest to them. The present disclosure contemplates that in some instances, this gathered data may include personal information data that uniquely identifies or can be used to contact or locate a specific person. Such personal information data can include demographic data, location-based data, telephone numbers, email addresses, TWITTER® ID's, home addresses, data or records relating to a user's health or level of fitness (e.g., vital signs measurements, medication information, exercise information), date of birth, or any other identifying or personal information.

Therefore, although the present disclosure broadly covers use of personal information data to implement one or more various disclosed examples, the present disclosure also contemplates that the various examples can also be implemented without the need for accessing such personal information data. That is, the various examples of the present technology are not rendered inoperable due to the lack of all or a portion of such personal information data. For example, content can be selected and delivered to users by inferring preferences based on non-personal information data or a bare minimum amount of personal information, such as the content being requested by the device associated with a user, other non-personal information available to the content delivery services, or publicly available information.

The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described examples. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described examples. Thus, the foregoing descriptions of the specific examples described herein are presented for purposes of illustration and description. They are not target to be exhaustive or to limit the examples to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.