US20190299268A1

US20190299268A1 - Method and apparatus for progressively forging a mobile device casing

Info

Publication number: US20190299268A1
Application number: US15/942,419
Authority: US
Inventors: Kung Ying LAW; Yut Chai LOH
Original assignee: Cheung Woh Technologies (zhuhai) Co Ltd
Current assignee: Cheung Woh Technologies (zhuhai) Co Ltd
Priority date: 2018-03-30
Filing date: 2018-03-30
Publication date: 2019-10-03

Abstract

A method and apparatus for progressively forging a mobile device casing is described. The method may include advancing an initial mobile device casing cut from an extruded sheet through a plurality of stations of a transfer die assembly. The method may also include performing a sequence of forgings on the initial mobile device casing to progressively form a mobile device casing having at least one three dimensional feature formed within at least one cavity of the progressively formed mobile device casing.

Description

CROSS REFERENCE TO PRIOR APPLICATION

The present application claims priority to Chinese Patent Application No. 2017102091051 filed on Mar. 31, 2017, entitled “METHOD AND APPARATUS FOR PROGRESSIVELY FORGING A MOBILE DEVICE CASING,” currently pending.

FIELD

Embodiments of the present invention relate generally to the field of manufacturing metal parts and more specifically, a manufacturing process for forming a mobile device casing.

BACKGROUND

The housings of a mobile devices, such as housing for handheld devices (e.g., a mobile telephone, gaming device, music player, medical device, etc.), tablet computing devices, laptop computing device bodies, laptop computing keyboards, laptop computing device displays, as well as other mobile devices, typically includes a glass cover attached with adhesives and/or screws to the housing forming an enclosure, or are sandwiched between glass or ceramic covers fixed to the housing to form the enclosure. The enclosure supports and protects the mobile device assemblies, including supporting and protecting parts such as a printed circuit board, processor, memory, battery, cooling fans, camera lens(es), glass display, flexible cables, hinges, brackets, as well as other parts typically included within the various mobile device casings.
One conventional manufacturing process for forming a mobile device casing includes fully machining out the housing from a metal block. The machining operations include further machining of all the features (e.g., side walls, mounting holes, embosses, relieve surfaces, etc. of the mobile device casing). Machined housings, however, typically increase the time and cost of manufacturing the mobile device casing.
Another typical approach for manufacturing a mobile device casing includes press working or “deep drawing” a sheet of metal to form the housing. After the press working, the features are then machined similar to the fully machined process of forming the mobile device casing. Press working a sheet of metal to form a mobile device casing results in a housing with even material thickness throughout the entire housing. Typically, the material thickness is the same sheet thickness as the original sheet material that was press worked. Then, to achieve features and/or different material thickness when forming the mobile device casing, the additional machining operations are required which increases time and expense in forming the mobile device casing. Furthermore, there may be relief surfaces that have a very thin material thickness after machining, thereby adversely affecting the rigidity of the housing.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention are illustrated by way of example, and not limitation, in the figures of the accompanying drawings in which:

FIG. 1A illustrates one embodiment of a system for progressively forging a mobile device casing with three dimensional features formed within at least one cavity of the casing.

FIG. 1B illustrates another embodiment of a system for progressively forging a mobile device casing with three dimensional features formed within at least one cavity of the casing.

FIG. 2 illustrates a block diagram of a method 200 of progressively forging a mobile device casing with at least one three dimensional feature formed within at least one cavity of the housing.

FIG. 3A illustrates cross sectional views of different stages of progressive forging operations to form a bowl shaped mobile device casing.

FIG. 3B illustrates one embodiment of a front-side view of the fully formed bowl shaped mobile device casing.

FIG. 3C illustrates another embodiment of a front-side view of the fully formed bowl shaped mobile device casing.

FIG. 3D illustrates one embodiment of a side view of the fully formed bowl shaped mobile device casing.

FIG. 4A illustrates cross sectional views of different stages of progressive forging operations to form an i-frame mobile device casing.

FIG. 4B illustrates one embodiment of a front-side view of the fully formed i-frame mobile device casing.

FIG. 5A illustrates one embodiment of a perspective view of a front side of a progressively forged mobile device casing with three dimensional features within at least one cavity of the mobile device casing.

FIG. 5B illustrates one embodiment of a perspective view of a back side of a progressively forged mobile device casing.

FIG. 6A illustrates one embodiment of a perspective view of a front side of a progressively forged laptop bottom casing with three dimensional features within at least one cavity of the laptop monitor casing.

FIG. 6B illustrates one embodiment of a perspective view of a back side of a progressively forged laptop bottom casing.

FIG. 7A illustrates one embodiment of a perspective view of a front side of a progressively forged laptop screen casing with three dimensional features within at least one cavity of the laptop monitor casing.

FIG. 7B illustrates one embodiment of a perspective view of a back side of a progressively forged laptop screen casing.

FIG. 8A illustrates one embodiment of a perspective view of a front side of a progressively forged laptop body casing with three dimensional features including a keyboard enclosure within at least one cavity of the laptop monitor casing.

FIG. 8B illustrates one embodiment of a perspective view of a back side of a progressively forged laptop body casing.

FIG. 9A illustrates one embodiment of a perspective view of a front side of a progressively forged i-frame mobile device casing with three dimensional features within at least a first cavity of the mobile device casing.

FIG. 9B illustrates one embodiment a perspective view of a back side of a progressively forged i-frame mobile device casing with three dimensional features within at least a second cavity of the mobile device casing.

FIG. 10A illustrates one embodiment a view of a front side of a progressively forged mobile device casing with a honeycomb feature forged within at least a portion of a cavity of the mobile device casing.

FIG. 10B illustrates a close up view of one embodiment of the honeycomb feature.

FIG. 10C illustrates another close up view of one embodiment of the honeycomb feature.

FIG. 10D illustrates a cross-sectional view of one embodiment of the honeycomb feature.

FIG. 11A illustrates a cross-sectional view of one embodiment of a progressively forged mobile device casing.

FIG. 11B illustrates grain structure and flow of portions of the progressively forged mobile device casing of FIG. 11A.

DETAILED DESCRIPTION

A method for progressively forging a mobile device casing having one or more three dimensional features is described. As discussed herein, the mobile device casing may be a casing for one of a handheld device (e.g. mobile telephone, gaming device, medical device, music player, etc.), a tablet computer, a laptop computer display, a laptop computer body, a laptop computer keyboard body, as well as other mobile device casings. In embodiments, the mobile device casing may be a bowl shaped casing having a cavity formed on a front side of the mobile device casing and having one or more three dimensional features forged within a cavity in the front side of the mobile device casing. The mobile device casing may also be, in embodiments, an i-frame (e.g., i-shaped) mobile device casing with a front side cavity and a back side cavity each having one or more three dimensional features formed therein. In either embodiment, the mobile device casing is progressively formed over a sequence of progressive forging operations, as described in greater detail herein.
In embodiments, an initial mobile device casing is cut from an extruded sheet of material, such as aluminum, steel, or other suitable metallic material. A specific sequence of forgings is then performed on the initial mobile device casing to progressively form the mobile device casing having one or more three dimensional feature within at least one cavity of the mobile device casing. The sequence of progressive forgings may be performed by a system, such as a transfer die assembly that advances the initial mobile device casing (e.g., a blank cut from a sheet of metal, cut from an extruded sheet, etc.) through multiple stations of the transfer die assembly. A plurality of the stations from the multiple stations perform a sequence of progressive forgings to form the mobile device casings, such as a mobile phone enclosure, tablet computer enclosure, laptop monitor enclosure, laptop body enclosure, etc. In one embodiment, the progressive stages of forging can be performed at room temperature. In another embodiment, one or more of the progressive stages includes pre-heating a partially formed mobile device casing to a predetermined temperature for a minimum duration of time before performing a forging operation. In embodiments, a combination of room temperature and pre-heated forging stages can be used in the series of progressive forging operations.
The forging of the mobile device casing utilizes the progressive forging operations over the series of forging stages to manage plastic deformation that displaces material with each forging operation. By utilizing plastic deformation of the material of the initial mobile device casing over the series of forging stages, the material usage to make the casing will be greatly reduced. Furthermore, the progressive forgings will result in work-hardening of the resulting mobile device casing, therefore improving its mechanical properties, such as rigidity and tensile strength of the fully formed mobile device casing. That is, non-homogeneous stress distortion of the material of the casing and the features formed therein will be reduced, and will have a more compact grain structure from the working hardening effect. For example, FIG. 11A illustrates a cross-sectional view of a progressively forged mobile device casing 1100, including curved wall section 1102, a three dimensional feature 1104 within a cavity of the mobile device casing, and another curved wall section 1106. While the metal material of an initial mobile device casing blank (e.g., the blank cut from an extruded sheet, metal sheet, etc.) will have fine, equiaxel grains of a uniform size before forging, FIG. 11B illustrates a close up view of the grain structure and flow of the curved wall portions 1102 and 1106 and the three dimensional feature 1104, obtained from the progressive forging operations. In embodiments, after the progressive forging operations discussed herein, there is a grain structure and flow that is elongated in a direction of deformation of the metal material of the formed mobile device casing as illustrated in FIG. 11B, which provides for increased strength and rigidity of the formed mobile device casing.
Furthermore, the progressive forging operations over the series of forging stages are able to form one or more three dimensional features within one or more cavities of the mobile device casing (e.g., a front side cavity of a bowl-shaped mobile device casing, as well as front and/or back side cavities of an i-frame mobile device casing). The formed three dimensional features are close in shape to a final version of those features, and the walls of the progressively forged mobile device casing are thinner than in conventional approaches. Therefore, machine cycle time and cost is greatly reduced when finishing the mobile device casing, as only refinement and not formation of the parts and/or walls is performed to finalize the structure of the mobile device casing. Furthermore, reduced wall thickness decreases the overall weight of the mobile device casing, and thus the resulting mobile device weight. In embodiments, 3000, 5000, 6000, 7000 series aluminum or stainless steel is utilized in the forging processes discussed herein and will result in a mobile device casing with better rigidity, tensile strength and grain structure, as compared to casings formed from conventional methods.
FIG. 1A illustrates one embodiment of a system 100 for progressively forging a mobile device casing having one or more three dimensional within at least one cavity of the casing. In one embodiment, the system 100 performs one or more forging operations at different press forging stages (e.g., stages 120-1 through 120-N) at room temperature (e.g., cold forging). Performing progressive forging operations using the system illustrated in FIG. 1A reduces non-homogeneous stress distortion in the forged mobile device casing, and can utilize aluminum alloy with temper 4 and below. Furthermore, if homogeneous hardness of the mobile device casing is part an end product design, solutionized heat treatment followed by artificial aging can be performed on the part after any of the stages illustrated in FIG. 1A.
For one embodiment, an extruded sheet of metal 110 is progressively formed in a series of transfer dies over a sequence of progressive forging stages (e.g., stages 120-1 through 120-N) to form mobile device casing 150. In embodiments, the formed mobile device casing 150 can be a bowl shaped, i-frame, or other form of mobile device casing. The press plates of the transfer dies that perform forging operations are coated in a titanium nitride (“TiN”) coating, or made from high speed steel or carbide tool steel, to increase the hardness of the press plates, and increase the tool life of the press plates, as well as to improve the efficiency of the forging. For one embodiment, the TiN coating is periodically removed (i.e., about every 300,000 pressings) from the transfer die machines, and a new coating of TiN is applied to the forging press plates. For one embodiment, additional press working operations are performed in additional stages by additional machines (not shown) to further form the mobile device casing, including trimming, piercing, stamping, coining, or other suitable processes. However, the final shape of the mobile device casing 150, and the three dimensional features contained therein, is close to final shape of the finished mobile device casing.
For one embodiment, the aluminum alloy, stainless steel, or other metal material used to form the bowl shaped mobile device casing may be chosen based on various factors—for example, design requirements, desired material properties, reduced contamination (i.e., silicon, copper, zinc, etc. contamination) of the raw material for the mobile device casing, and reduced natural magnetism of the mobile device casing. For one embodiment, an aluminum alloy in the form of the extruded sheet 110 is initially used to prepare a blank for forming the mobile device casing. The thickness and profile of the extruded sheet 110 may vary depending on a particular product design.
A progressive die assembly utilized to form mobile device casing 150 with a sequence of progressive forging operations may include multiple stations at stages 120-1 through 120-N. The initial mobile device casing (e.g., extruded sheet 110) is advanced from station to station to complete each of the plurality of progressive forgings. Each station may perform forgings, as well as other machining operations, from more than one stage. The specific forging operations form, either partially or fully, parts within the b mobile device casing as it is advanced through the sequence of stages. The sequence of progressive forgings form, either partially or fully, specific parts within one or move cavities of the mobile device casing at specific stages in order to manage the movement of material caused by the forging operations, and to ensure a uniform thickness of the resulting fully formed mobile device casing 150. Furthermore, the order of forging operations and formation of different parts ensures that the three dimensional features within the one or more cavities of the mobile device casing are accurately and properly formed.
In an embodiment, the internal stresses of the formed mobile device casing may be removed by annealing. Annealing may be performed before advancing the mobile phone enclosure to one or more forging die assembly stages. As discussed above, one or more of the progressive stages of forging are performed at room temperature, and annealing may be used between one or more stage of the sequential and progressive process. For example, a mobile device casing being forged by the sequential and progressive forging stages may be annealed after every other stage, every three stages, between select stages, etc. For one embodiment, annealing is performed by heating the mobile device casing being forged to approximately 390 degrees Celsius, and then allowing the enclosure to cool. Different annealing temperatures may be used between different stages.
Due to the malleability of material caused by work hardening during a cold forging process, in embodiments hot forging with pre-heating between one or more forging stages is utilized for extending mobile device casing wall height and/or height of three dimensional features.
FIG. 1B illustrates another embodiment of a system 160 for forging a mobile device casing with one or more three dimensional features formed within one or more cavities of the mobile device casing. The system illustrated in FIG. 1B may be used when pre-heating of a partially formed mobile device casing is desired before one or more subsequent forging stages. Again, if homogeneous hardness of the mobile device casing is desired for an aluminum casing material by end product design, solutionized heat treatments followed by artificial ageing can be used on the partially formed mobile device casing. If homogeneous hardness for a steel material mobile device casing is desired by the end product design, heat treatment hardening followed by tempering can be used.
As illustrated in FIG. 1B robots 130-1, 130-2, through 130-P, or other mechanical pick-and-place means, are used to transfer a partially formed mobile device casing to one or more ovens 140-1, 140-2, through 140-M, between one or more of the forging stages 120-1, 120-2, through 120-N. In embodiments, the ovens pre-heat the partially formed mobile device casing before transfer back to a subsequent press forging stage. For one embodiment, the partially formed mobile device casing is heated to a predetermined temperature, such as 300° C. Furthermore, once the temperature reaches the predetermined temperature, the mobile device casing is held in the oven at that temperature for a minimum duration of time, such as 30-45 minutes, before transfer back to a press forging stage. Because the partially formed mobile device casing is pre-heated before one or more subsequent forging operations, the height of side walls and/or three dimensional features within one or more cavities can be increased well over conventional approaches.
The robotic arms or other mechanical means performs the transfer because transfer to and from the oven to and from the various press forging stages (e.g., stages 120-2, 120-3, through 120-N) is a time sensitive operation. That is, to prevent heat loss during the transfer to and from the oven to the various press forging stages, the robotic arms and/or other mechanical means are employed so that the transfer may be achieved in under a maximum duration of transfer time, such as not more than 8 seconds. The next forging operations are then performed at the next press of press forging stage. These forging operations can include partially or fully forming existing or additional parts of the mobile device casing, as discussed herein.
FIG. 2 illustrates a block diagram of a method 200 of progressively forging a mobile device casing with at least one three dimensional feature formed within at least one cavity of the housing. A progressive die assembly used in the method illustrated by FIG. 2 may include multiple stations with a mobile device casing advanced from station to station, and optionally preheated in between one or more of the multiple stages, as discussed above. The method includes performing a sequence of progressive forgings using the transfer die assembly.
The method begins by advancing an initial blank for a mobile device casing to a first forging stage of a sequence of progressive forging stages for forming a mobile device casing (block 202). A forging operation is then performed in a sequence of forging operations on the mobile device casing to progressively form a mobile device casing having one or more three dimensional features within at least one cavity of the mobile device casing (block 204). As discussed herein, a sequence of progressive forging operations may be performed, and block 204 may be repeated any number of times corresponding to the number of different progressive forging operations. Furthermore, as discussed herein, additional operations, such as pre-heating prior to one or more forging operations, annealing after forging, performing a solutionized heat treatment, etc. may be performed before/after one or more of the progressive forging stages.
After the progressive forging operation(s) have been completed, the mobile device casing may be transferred to a finishing stage where the mobile device casing is finished (block 206). As discussed above, finishing the mobile device casing can involve one or more of trimming excess material; punching, piercing, or drilling holes; performing one or more washing processes; performing a coating process, as well as other finishing operations.
Although not illustrated, the finished mobile device casing having one or more three dimensional features forged into one or more cavities of the casing can then be transferred to another stage of a mobile device assembly process (e.g., installing parts on the finished mobile device casing such as a display, sensors, processors, input device, cameras, etc.).
FIG. 3A illustrates cross sectional views of different stages of progressive forging operations to form a bowl shaped mobile device casing. The mobile device casing is referred to as bowl shaped because the mobile device includes rounded side walls and a cavity that makes up substantially all of a front side of the mobile device casing (except the side walls and three dimensional features). An initial flat rectangular sheet 302 of metal material (e.g., an extruded sheet of an aluminum or steel alloy) has an initial width 306 and an initial material thickness 304. Selection of the material thickness and the sheet's profile is dependent on particular design considerations of the finished bowl shaped mobile device casing. Furthermore, the order of forging operations and formation of different parts (e.g., the three dimensional features) ensures that the intricate details of the mobile device casing are properly formed.
A forging operation is performed on the initial sheet 302 to obtain a partially formed bowl shaped mobile device casing 310. The first forging stage raises the height of the side walls from thickness 304 to height 312, and reduces both the plate thickness 314 and overall width 316. After a second forging stage, the partially formed bowl shaped mobile device casing 320 is fed into a die that further raise the height 322 of the side walls and one or more three dimensional features 328 within a cavity of a front side of the mobile device casing, while also reducing both the plate thickness 324 and width 326. As discussed herein, plastic deformation is used to displace material between subsequent progressive forging stages. Then, after a third forging stage, a fully formed bowl shaped mobile device casing 330 is formed, height 332 of the side walls and height 338 of the three dimensional features is increased while at the same time reducing width 336 and plate thickness 334 of the casing 330. In embodiments, the three dimensional features need not have the same height as the side walls, and each three dimensional feature may have a different height, as specified by one or more design constraints of the finished mobile device casing.
FIG. 3B illustrates one embodiment of a front-side view of the fully formed bowl shaped mobile device casing 350. Section X-X 340 of formed mobile device casing 330 is shown in the front-side view of casing 350, also having width 336, and a height 358. Furthermore, section X-X 340 illustrates three dimensional features 362 of FIG. 3C, which may also include additional three dimensional 360 and other features, within the front side cavity of the bowl shaped mobile device casing. In embodiments, the side walls 354 of the bowl shaped mobile device casing are formed during the progressive forging operations to be curved in order give the casing its bowl-shaped appearance. FIG. 3D illustrates a height 370 of the walls of the fully formed bowl shaped mobile device casing.
FIG. 4A illustrates cross sectional views of different stages of progressive forging operations to form an i-frame mobile device casing. Similar to FIG. 3A discussed above, an initial flat rectangular sheet 402 of metal material (e.g., an extruded sheet of an aluminum or steel alloy) has an initial width 406 and an initial thickness 404. As discussed above, selection of the material thickness and the sheet's profile is dependent on particular design considerations of the finished i-frame mobile device casing. Furthermore, the order of forging operations and formation of different parts (e.g., the three dimensional features) ensures that the intricate details of the mobile device casing are properly formed.
After a first forging operation in the series of progressive forging stages, a partially formed i-frame mobile device casing 410 is formed with height of the side walls raised from the initial sheet's thickens 404 to sidewall height 412. Furthermore, other thicknesses of the plate are reduced to thickness 418 and thickness 413. Other material movement and the forging operations results in a three dimensional feature with height 414, and the width of the plate increasing to width 416.
After a second forging operation in the series of forging stages, the partially formed i-frame mobile device casing 420 is further formed including the side wall height being reduced to height 421, both the plate thickness 423 and 424 being reduced, the feature height is increased 422, and the width is increased to width 426. As in FIG. 3A, plastic deformation techniques are utilized to displace material and manage material movement by the progressive forging stages to obtained a desired and/or uniform thickness of the fully formed mobile device casing.
Then, after a third forging operations in the series of forging stages, the i-frame mobile device casing 430 is fully formed. In particular, the height of the side walls is increased to height 431, the three dimensional feature height is increased to height 432, the overall width of the casing is increased to width 436, the plate thickness is reduced to thickness 433, and features near the side walls are formed. As noted above, the three dimensional feature need not have the same height, and may have different heights based on one or more design requirements. FIG. 4B illustrates one embodiment of a front-side view of the fully formed i-frame mobile device casing 450, wherein the casing has width 436, height 408, an one or more three dimensional features formed within a front-side and/or back-side cavity of the mobile device casing.
In one embodiment, a honeycomb cell feature may be added/formed on the front side and/or back side of either the bowl shaped or i-frame mobile device casing with an additional forging operation performed on a fully formed mobile device casing. FIG. 10A illustrates one embodiment a view of a front side of a progressively forged mobile device casing 1000 having width 1002 and length 1004, and a honeycomb feature in at least region 1010. One or more honeycomb features may also be formed on other region(s) of the mobile device casing 1000 consistent with the discussion herein. In embodiments, the honeycomb feature 1010 is forged within at least a portion of a cavity of the mobile device casing, a portion of side walls, a portion of a back side, etc. The addition of the honeycomb cell feature increases the formed mobile device casing's rigidity and stiffness. FIG. 10B illustrates a close up view 1014 of the honeycomb feature 1010 formed near sidewall 1012 of a mobile device casing. FIG. 10C illustrates another close up view including one embodiment of dimensions 1020 for the honeycomb feature along cross section A-A of FIG. 10A. FIG. 10D illustrates a cross-sectional view of one embodiment of the honeycomb feature including relative heights and depths of the honeycomb feature and plate thickness. The particular dimensions illustrated in FIGS. 10C and 10D, such as spacing, depth, and volume of cells, are illustrative and are expressed in relative size of their respective dimensions, and can be altered based on various design considerations. Furthermore, although a hexagonal cell shape detail is illustrated in FIGS. 10B-10D, other dimensions and shapes, such as circles, octagons, etc. may also be utilized as a cell feature forged into a mobile device casing to increase strength and rigidity. Furthermore, by adding the honeycomb feature through a forging operation in the series of progressive forgings, the honeycomb cell feature can be added to the front side and/or back side of the mobile device casing with a high degree of precision and accuracy, without the increased cost, quality control issues, and commercial impracticability of creating such a feature using die cast or machining methods.
As discussed herein, the progressive forging operations may be utilized to form a bowl-shaped or i-frame mobile device casing, such as the cellular phone casings illustrated in FIGS. 3B-3D and 4B. However, the techniques discussed herein may be used to form other mobile device casings with three dimensional features forged into at least one cavity of the mobile device casing. In one embodiment, a front-side view and a back side view 550 of a progressively forged tablet/phablet casing 500 (e.g., having larger dimensions than a mobile telephone casing) is illustrated in FIGS. 5A and 5B. Like the mobile telephone casing, the tablet/phablet casing 500 has rounded side walls 502 and 552, and a plurality of three dimensional features 504 forged within a cavity of the tablet/phablet casing 500.
In another embodiment, an interior surface view 600 and an exterior surface view 650 of a progressively forged laptop body computer casing having rounded side walls 602 and 652, as well as three dimensional features 604, as illustrated in FIGS. 6A and 6B. Similarly, FIGS. 7A and 7B illustrate a laptop computer casing for a display. The interior surface view 700 includes three dimensional features 704 and rounded side walls 702, while the exterior surface view 750 also has rounded side walls. Another embodiment of a progressively forged laptop body computer casing 800 for a keyboard having rounded side walls 802 and 852, as well as three dimensional features 804, is illustrated in FIGS. 8A and 8B.
In yet another embodiment, a front side of a progressively forged i-frame mobile device casing 900 for a tablet or phablet computing device is illustrated in FIG. 9A. The housing 900 includes three dimensional features 904 formed within at least a first cavity of the mobile device casing 900. The i-frame mobile device casing 900 has an i-frame body (e.g., similar to FIG. 4B), and includes rounded side walls 902 around the perimeter of the mobile device casing 900. FIG. 9B illustrates back side perspective view 950 of the progressively forged i-frame mobile device casing, with additional three dimensional features 954 formed in a second cavity of the back side of housing 950, and the side walls 902 around the perimeter of the housing.
In the foregoing specification, the invention has been described in reference to specific exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the described spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded as illustrative rather than a restrictive sense.

Claims

What is claimed is:

1. A method for progressively forging a mobile device casing, comprising:

advancing an initial mobile device casing cut from an extruded sheet through a plurality of stations of a transfer die assembly; and

performing a sequence of forgings on the initial mobile device casing to progressively form a mobile device casing having at least one three dimensional feature formed within at least one cavity of the progressively formed mobile device casing.

2. The method of claim 1, wherein the progressively formed mobile device casing comprises a bowl shaped mobile device casing with rounded side walls having a cavity formed on a front side of the bowl shaped mobile device casing and having one or more three dimensional features forged within a cavity in the front side of the bowl shaped mobile device casing.

3. The method of claim 2, wherein performing the sequence of forgings on the initial mobile device casing progressively forms the bowl shaped mobile device casing, further comprising:

performing a first forging operation in the sequence of forging stages to form a first partially formed bowl shaped mobile device casing comprising at least raising a side wall height, reducing a plate thickness, and reducing a casing width;

performing a second forging operation in the sequence of forging stages to form a second partially formed bowl shaped mobile device casing comprising at least further raising the side wall height, raising a height of at least one three dimensional feature within a cavity of a front side of the second partially formed bowl shaped mobile device casing, further reducing the plate thickness, and further reducing the casing width; and

performing a third forging operation in the sequence of forging stages to fully form the bowl shaped mobile device casing comprising at least further raising the side wall height to a final side wall height, further raising the height of the least one three dimensional feature within the cavity of the front side of the fully formed bowl shaped mobile device casing to a final feature height, further reducing the plate thickness to a final plate thickness, and further reducing the casing width to a final casing width.

4. The method of claim 1, wherein the progressively formed mobile device casing comprises an i-frame mobile device casing having a cavity formed on a front side and a back side of the i-frame mobile device casing and having at least one three dimensional feature forged within the cavity of the front side and at least one three dimensional feature forged within the cavity of the back side of the i-frame mobile device casing.

5. The method of claim 4, wherein performing the sequence of forgings on the initial mobile device casing progressively forms the i-frame mobile device casing further comprises:

performing a first forging operation in the sequence of forging stages to form a first partially formed i-frame shaped mobile device casing comprising at least raising a side wall height, raising a height of at least one three dimensional feature within the cavity of the front side of the second first partially formed i-frame mobile device casing, and increasing a casing width;

performing a second forging operation in the sequence of forging stages to form a second partially formed i-frame mobile device casing comprising at least further raising the side wall height, reducing one or more regions of plate thickness, further raising the height of the at least one three dimensional feature within the cavity of the front side of the second partially formed i-frame mobile device casing, and further increasing the casing width; and

performing a third forging operation in the sequence of forging stages to fully form the i-frame mobile device casing comprising at least further raising the side wall height to a final side wall height, further raising the height of the at least one three dimensional feature within the cavity of the front side to a final feature height, further reducing the one or more regions of plate thickness, further increasing the casing width to a final casing width, and forming at least one three dimensional feature proximate to at least one side wall of the fully formed i-frame mobile device casing.

6. The method of claim 1, wherein performing the sequence of forgings on the initial mobile device casing further comprises:

performing a forging operation on the progressively formed mobile device casing that forms a honeycomb cell feature on at least a portion of a front side, a back side, sidewalls, or a combination thereof, of the progressively formed mobile device casing.

7. The method of claim 1, wherein performing the sequence of forgings on the initial mobile device casing further comprises:

annealing the mobile device casing after one or more stages in the sequence of forgings.

8. The method of claim 1, wherein one or more stages in the sequence of forgings are performed at room temperature.

9. The method of claim 8, wherein a solutionized heat treatment followed by artificial aging is applied to a partially formed mobile device casing after the one or more stages performed at room temperature to obtain a homogeneous hardness of the formed mobile device casing.

10. The method of claim 1, wherein one or more stages in the sequence of forgings includes pre-heating a partially formed mobile device casing to a predetermined temperature for a minimum duration of time before performing a forging operation.

11. The method of claim 10, wherein a heat treatment hardening followed by tempering is applied to a partially formed mobile device casing after the one or more stages that include pre-heating to obtain a homogeneous hardness of the formed mobile device casing.

12. The method of claim 1, wherein press plates of stations of the transfer die assembly that perform the forging operations are coated with titanium nitride.

13. The method of claim 1, wherein the mobile device casing is formed from an aluminum alloy.

14. The method of claim 1, wherein the mobile device casing is formed from a steel alloy.

15. The method of claim 1, wherein the mobile device casing comprising one of a mobile phone enclosure, a phablet computer enclosure, a tablet computer enclosure, a laptop monitor enclosure, a laptop body enclosure, or a laptop keyboard enclosure.

16. An apparatus for progressively forging a mobile device casing, comprising:

a transfer die assembly to advance an initial mobile device casing cut from an extruded sheet through a multiple stations of the transfer die assembly; and

a plurality of stations from the multiple stations to perform a sequence of forgings on the initial mobile device casing to progressively form a mobile device casing having at least one three dimensional feature formed within at least one cavity of the progressively formed mobile device casing.

17. The apparatus of claim 16, wherein the progressively formed mobile device casing comprises a bowl shaped mobile device casing with rounded side walls having a cavity formed on a front side of the bowl shaped mobile device casing and having one or more three dimensional features forged within a cavity in the front side of the bowl shaped mobile device casing.

18. The apparatus of claim 17, wherein the sequence of forgings performed by the plurality of stations on the initial mobile device casing progressively forms the bowl shaped mobile device casing, further comprises:

a first forging station that performs a first forging operation in the sequence of forging stages to form a first partially formed bowl shaped mobile device casing comprising the first forging station at least raising a side wall height, reducing a plate thickness, and reducing a casing width;

a second forging station that performs a second forging operation in the sequence of forging stages to form a second partially formed bowl shaped mobile device casing comprising the second forging station at least further raising the side wall height, raising a height of at least one three dimensional feature within a cavity of a front side of the second partially formed bowl shaped mobile device casing, further reducing the plate thickness, and further reducing the casing width; and

a third forging station that performs a third forging operation in the sequence of forging stages to fully form the bowl shaped mobile device casing comprising the third forging station at least further raising the side wall height to a final side wall height, further raising the height of the least one three dimensional feature within the cavity of the front side of the fully formed bowl shaped mobile device casing to a final feature height, further reducing the plate thickness to a final plate thickness, and further reducing the casing width to a final casing width.

19. The apparatus of claim 16, wherein the progressively formed mobile device casing comprises an i-frame mobile device casing having a cavity formed on a front side and a back side of the i-frame mobile device casing and having at least one three dimensional feature forged within the cavity of the front side and at least one three dimensional feature forged within the cavity of the back side of the i-frame mobile device casing.

20. The apparatus of claim 19, wherein the sequence of forgings performed by the plurality of stations on the initial mobile device casing progressively forms the i-frame mobile device casing, further comprising:

a first forging stage that performs a first forging operation in the sequence of forging stages to form a first partially formed i-frame shaped mobile device casing comprising the first forging stage at least raising a side wall height, raising a height of at least one three dimensional feature within the cavity of the front side of the second first partially formed i-frame mobile device casing, and increasing a casing width;

a second forging stage that performs a second forging operation in the sequence of forging stages to form a second partially formed i-frame mobile device casing comprising the second forging stage at least further raising the side wall height, reducing one or more regions of plate thickness, further raising the height of the at least one three dimensional feature within the cavity of the front side of the second partially formed i-frame mobile device casing, and further increasing the casing width; and

a third forging stage that performs a third forging operation in the sequence of forging stages to fully form the i-frame mobile device casing comprising the third forging stage at least further raising the side wall height to a final side wall height, further raising the height of the at least one three dimensional feature within the cavity of the front side to a final feature height, further reducing the one or more regions of plate thickness, further increasing the casing width to a final casing width, and forming at least one three dimensional feature proximate to at least one side wall of the fully formed i-frame mobile device casing.

21. The apparatus of claim 16, wherein the mobile device casing comprising one of a mobile phone enclosure, a phablet computer enclosure, a tablet computer enclosure, a laptop monitor enclosure, a laptop body enclosure, or a laptop keyboard enclosure.