The present invention relates in general to the field of information handling system housings, and more particularly to a carbon fiber information handling system low housing and process for manufacture.
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Portable information handling systems continue to shrink in size and increase in capability. Reduced physical size is made practical in part by decreased size and increased capability of processing components used to build portable information handling systems, such as central processing units (CPUs) and graphical processing units (GPUs). Generally, portable information handling system housing size in length and width (X and Y vectors) are driven by the size of the flat panel display integrated in the housing. Tablet information handling systems have a planar housing with a display integrated on one side across most of the width and height, and have processing components disposed underneath the display in a main housing portion. Clamshell and convertible information handling systems have a main housing portion that integrates a keyboard and rotationally couples to a lid housing portion that integrates a display. Rotation of the main and lid housing portions between closed and opened positions lets a user view the display in a raised position while typing inputs at the integrated keyboard, or lets the user expose the display for use in a tablet mode.
Since system width and length are driven by display size, system height (Z vector) often becomes the primary focus for decreasing overall system size and weight. System height is reduced with careful selection of processing components and careful layout of the processing components in the available housing volume so that power and heating constraints are met. Housings typically must have sufficient rigidity to avoid excessive stress placed on processing components or the display during normal use. Torsional stress may be introduced during rotational movement of housing portions relative to each other or during touches at a display of a planar housing. Insufficient housing strength can result in system failures from housing cracks or due to excessive stress placed on electrical connections, such as a motherboard. Excessive housing structure adds to system weight and height, and also tends to increase system cost.
In an effort to provide increased structural soundness with decreased thickness and weight, industry has moved to various alternative materials to build housings, such as carbon fiber composite material. Current manufacturing processes for carbon fiber composite housings used in electronics devices involves a number of steps that tend to have a relatively low roll through put yield. Generally, forming and finishing carbon fiber composite housing portions is a manual process that tends to introduce variations that impact robustness and aesthetics of the components. In a typical manufacture process, forming the correct shape alone can consume 6 to 7 minutes with additional process steps increasing total cycle time to exceed 15 to 20 minutes per part. As a result, carbon fiber material typically is limited to use in low volume and high cost products.
Therefore, a need has arisen for a system and method which provides carbon fiber information handling system housing manufacture in volume.
In accordance with the present invention, a system and method are provided which substantially reduce the disadvantages and problems associated with previous methods and systems for carbon fiber information handling system housing manufacture. A carbon fiber composite prepreg material has an external decorative and protective coat applied with a polyethylene terephthalate (PET) film applied in a mold process that provides a completed carbon fiber housing with minimal post mold treatment.
More specifically, a carbon fiber prepreg material is fabricated to a mold shape, such as with CNC machining, and inserted into a mold, such as in a mold cavity or on a mold core. The carbon fiber prepreg material is preheated and then placed in a heated mold. Preheating the prepreg material before inserting into the mold reduces cycle time for transition to a carbon fiber composite. While disposed in the mold and before the mold is closed, the carbon fiber prepreg has a PET film applied at the outer surface. The mold closes to apply heat to the prepreg material for transition into a carbon fiber composite. During application of the heat, adhesive, ink and a protective coating layer transfer from the PET film by heat to integrate with the carbon fiber prepreg and composite so that the completed housing piece has a protective outer surface at the outer surface of the housing, including decorative ink designs if desired. For example, the PET film transfers a protective ultraviolet (UV) hard coat or a soft touch polyurethane (PU) coating layer. The outer protective surface deposited by the in mold PET film integrates with resin of the prepreg material, such as with compatible thermoplastic or polycarbonate materials included in the resin and outer coating that react with each other in a compatible manner. Combining forming, heating, insert molding and decoration into a single in mold process step improves manufacture efficiency and provides improved variance control.
The present invention provides a number of important technical advantages. One example of an important technical advantage is that volume production of finished carbon fiber composite housings is efficiently performed to provide high quality and cost effective electronic enclosure housings. In mold PET film treatment efficiently integrates a protective outer coat with carbon fiber prepreg material during heat treatment to transition the prepreg material into a carbon fiber composite material while using heat treatment as a catalyst for transfer the housing outer treatment that adds desired texture, color and patterns so that post process paint treatments are unnecessary. A single mold forming process step with exterior film treatment outputs a finished part in manner adapted to automated production. Limiting manual steps improves throughput, reduces component variance and allows high volume production of light weight yet robust housings for information handling systems. In one example implementation, rolled throughput yield of housings improved from 53% to 84% by applying outer surface treatment with PET film compared to conventional post mold treatments.
The present invention may be better understood, and its numerous objects, features and advantages made apparent to those skilled in the art by referencing the accompanying drawings. The use of the same reference number throughout the several figures designates a like or similar element.
Integration of an outer surface treatment from a PET film into a carbon fiber prepreg mold heat process efficiently treats an information handling system carbon fiber composite housing exterior. For purposes of this disclosure, an information handling system may include any instrumentality or aggregate of instrumentalities operable to compute, classify, process, transmit, receive, retrieve, originate, switch, store, display, manifest, detect, record, reproduce, handle, or utilize any form of information, intelligence, or data for business, scientific, control, or other purposes. For example, an information handling system may be a personal computer, a network storage device, or any other suitable device and may vary in size, shape, performance, functionality, and price. The information handling system may include random access memory (RAM), one or more processing resources such as a central processing unit (CPU) or hardware or software control logic, ROM, and/or other types of nonvolatile memory. Additional components of the information handling system may include one or more disk drives, one or more network ports for communicating with external devices as well as various input and output (I/O) devices, such as a keyboard, a mouse, and a video display. The information handling system may also include one or more buses operable to transmit communications between the various hardware components.
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Once prepreg material 38 is preheated and inserted into the mold, a PET (or similar) film 42 is applied to the outer surface of prepreg material 38 and mold 32 is closed to form a housing. In the example embodiment, an in mold roll of PET film 42 is performed by feeding PET film 42 roll to roll in between cavity 36 and core 34 of mold 32. PET film 42 is coated with an adhesive, ink and protective outer surface material that is compatible with the resin of the prepreg material. PET film 42 transfers the coating to the prepreg material for integration with the carbon fiber composite as the carbon fiber resin hardens. Heat 40 applied to transition prepreg 38 into carbon fiber composite is also used as the catalyst to get the ink/hardcoat to transfer off the roll foil and onto the housing part. The PET film material is compatible with the prepreg polycarbonate or similar resin so that the ink and outer coating material integrate with the carbon fiber composite in the hardening process to provide a protective and decorative outer surface. In the example embodiment, one side of the housing has the protective outer surface material covering. In alternative embodiments, both sides may have the protective outer surface material coating film applied. The carbon fiber composite may have a woven or unidirectional pattern and may include additional materials, such as glass fiber or aramids. In alternative embodiments, a glass fiber or aramid prepreg may be used in the place of a carbon fiber prepreg.
In some instances, housings have more complex geometries that make smooth application of a film difficult. As an alternative to in mold roll application of PET film 42, an in mold forming process is used to adapt the PET application to more complex geometries. PET film 42 is thermoformed to the mold shape, trimmed to match the mold shape, and then inserted into the mold, which is heated and closed to perform the PET outer surface film material transfer. Preforming the PET film to the mold shape provides smoothed application of the PET film to achieve deep draw and complicated geometries. In some embodiments, an ultraviolet cure is provided to the outer surface material after transfer of the material from the PET film to aid in hardening.
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Although the present invention has been described in detail, it should be understood that various changes, substitutions and alterations can be made hereto without departing from the spirit and scope of the invention as defined by the appended claims.