Patent Application
20070222122
The present invention relates to a brightened composite shell and a method for fabricating the same without blisters and pin-holes.
Products with a hard casing are used in a multiple variety of fields such as the case of computers, cellular phones, laptops, or suitcases. Generally, the hard cases can be made by plastic or metallic material such as Aluminum alloy or Magnesium alloy. The plastic casing can be made by way of injection molding and in order to obtain a thin and sophisticate casing, a more complicated method is developed to inject the plastic material. However, the complicated method is costly and the thin plastic casing has less structural strength so that it is easily to be broken.
The metallic casings are heavy and involve high-cost molds. Both of the plastic and metallic casings have to be coated with an outer protection layer to display its surface quality.
Another method uses a method of press molding to laminate multiple layers of composite material and the products are light and have better structural strength. Nevertheless, the casing needs to be coated with a transparent resin to have a bright and smooth outer surface. Besides, there are blisters or pin-holes generated during the processes of the method so that extra careful steps are taken to remove these blisters and pin-holes.
The present invention intends to provide a method for fabricating a brightened composite shell by way of vacuum molding and blisters and pin-holes are generated so that the products have stereo surfaces no generally coating processes.
The present invention relates to a shell with a brightened surface and the shell is made by the following steps which are:
step (a): providing an uncured composite material on a surface of a metallic mold, the composite material comprising lamination of pre-preg of matrix resin and fibers, a weight ratio of the matrix reins in the composite material being 30% to 60%;
step (b): curing the composite material by vacuum molding to form a semi-product; and
step (c): machining the cured composite semi-product by removing surplus material to become a final product.
The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.
Referring to
a step 11 of providing an uncured composite material 11;
a step 12 of providing a metallic mold;
a step 13 of providing surface treatment to the metallic mold;
a step 14 of providing the uncured composite, material 11 on the metallic mold;
a step 15 of curing the composite material by vacuum molding to form a consolidated semi-product, and a step 16 of machining by removing surplus material to become a final product.
The composite material can be one of a carbon-fiber composite material, a KEVLAR fiber composite material, a glass-fiber composite material, a dyed-fiber composite material and a hybrid-fiber composite material.
The composite material includes multiple laminations of pre-preg of matrix resin and fibers, a weight ratio of the matrix reins in the composite material being 30% to 60%. The contents of the matrix resin is one or two times of general pre-preg material. The matrix resin of the composite material is chosen from one of a thermosetting resin and a thermoplastic resin. The way of weaving of the fibers can be one of a unidirectional weave, a plain weave, a satin weave, a twill weave and a multi-axial weave.
The composite material is cut into proper sizes before being put on the metallic mold and the composite material and the metallic mold are sealed by using a sealing member.
The metallic mold is treated by a surface treatment to obtain a polished mold with a fine and smooth surface. The surface treatment includes a surface polish process and a surface hardening process. The surface polish process is one of the following methods which are mechanical polishing, chemical polishing, chemical-mechanical polishing (CMP). The surface hardening process can be one of the following treatments which are a surface chrome coating process, a surface titanium coating process, a surface carburizing process and a surface nitrogenzing process. The uncured composite material is then put on the metallic surface that is treated.
The vacuum molding is done by a vacuum appliance which can be one of the following devices which are an autoclave, an oven and a pump. The vacuum molding is to seal the composite material by using a seal member and the composite material is heated in a temperature between 0 to 1600 degrees Celsius under a pressure between 0 to 100 atmospheric pressure.
As shown in
The composite material 22 is then laminated on the metallic mold 21 at a proper angle. A seal member 23 is used to seal the metallic mold 21 and the composite material 22, and the sealed pack is sent to the vacuum appliance 2 to check the reliability of the sealing by the seal member 23.
The sealed pack of the composite material 22 is then laminated on the metallic mold 21 is sent into an oven or an autoclave to cure or consolidate. By proper setting of the temperature and pressure, the seal member 23 is removed and the semi-product is then machined to remove the surplus material to form the final product which has a brightened surface.
As shown in
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While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.
