Abstract:
An apparatus for manufacturing product with decorative patterns includes a fixed and a movable mold base, and a decorative film. A fixed mold insert is fitted in the fixed mold base and is provided with a sprue and at least one molding cavity. 
     The movable mold base is movable toward or away from the fixed mold base and includes an ejector pin unit and a movable mold insert, which is provided with at least one material receiving cavity. The decorative film is placed in between the fixed and the movable mold insert to cover the molding cavity and material receiving cavity, and is provided with a material passing opening corresponding to the sprue. A method for manufacturing product with decorative patterns is also disclosed to ensure increased yield rate of injection molded products with varied and precise surface patterns through effective cost control in the manufacturing process.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to an apparatus and method for manufacturing product with decorative patterns, and more particularly, to an apparatus and method for forming molded product with decorative patterns in a mold through one-step injection molding, so as to save time and labor and effectively reduce manufacturing cost while achieving the purposes of automated production and increased yield rate. 
       BACKGROUND OF THE INVENTION 
       [0002]    According to the conventional technology of in-mold decoration by roller, a printed plastic film wound into a roll is mounted in an injection molding machine and an injection molding mold for attaching to the surfaces of a plurality of injection molded products in a manner similar to labeling. Then, the molded products are removed from the injection molding machine via a full-automatic movable loop belt. This technology is also referred to as in-mold decoration injection molding. That is, patterns are printed onto a roll of PET (polyethylene terephthalate) plastic film, and the printed PET plastic film is fed by a film feeder into a mold, as shown in  FIG. 1A , and is then heated and sucked to a cavity in the mold, as shown in  FIG. 1B . When a material is injected into the mold cavity, the patterns printed on the PET plastic film are transferred onto the surface of the injection molded product, as shown in  FIG. 1C . Finally, the molded product with the PET plastic film attached thereto is removed from the mold cavity, as shown in  FIG. 1D , and the plastic film is peeled off from the molded product to obtain a finished product having printed patterns shown on the surface thereof. 
         [0003]    The conventional technology of in-mold decoration by roller as described above is disadvantageous because the printed patterns transferred onto the surface of the molded product is an ink layer only a few micrometers in thickness, and a transparent protective film must be further coated on the surface of the molded product to protect the thin layer of printed patterns against abrasion, scratch and color fading, lest the molded product should lose its aesthetic and quality appearance. 
         [0004]    Moreover, since a relatively long time and a considerably high cost are needed for developing a new product and new decorative patterns therefor, the conventional technology of in-mold decoration by roller is not suitable for small batch production. In other words, the conventional technology of in-mold decoration by roller is only suitable for large batch production of products with less change in curvature thereof, such as the cases and keys for mobile phones, the cases for notebook computers and the like. 
         [0005]    Another disadvantage of the conventional technology of in-mold decoration by roller is that the molded products must be manually cut from the cured plastic material in the runner after the mold is opened and the molded products are removed from the mold. This procedure increases the products&#39; labor and manufacturing costs, which apparently does not satisfy the requirement for high-efficient and automated production in the modern society and makes the products less competitive in the market. 
         [0006]    In view of the above-mentioned disadvantages, it is desirable to improve the conventional in-mold decoration technology by developing an apparatus and method for manufacturing product with decorative patterns in a simplified process, so as to increase the yield rate, the aesthetic appearance and the usability of the product at lowered manufacturing cost. 
       SUMMARY OF THE INVENTION 
       [0007]    A primary object of the present invention is to provide an apparatus for manufacturing product with decorative patterns, so that a plastic material injected into a mold can be molded along with a decorative film to form a molded product with decorative patterns, and the molded product is automatically cut from the cured plastic material in a runner of the mold when the mold is opened and the molded product is ejected from the mold, enabling largely increased production efficiency and yield rate of the product. 
         [0008]    To achieve the above and other objects, the apparatus for manufacturing product with decorative patterns according to the present invention includes a fixed mold base, a movable mold base, and a decorative film. The fixed mold base has a fixed mold insert fitted therein, and the fixed mold insert is provided with a sprue and at least one molding cavity. 
         [0009]    The movable mold base has a movable mold insert fitted therein and includes an ejector pin unit, and is selectively movable toward or away from the fixed mold base to enable mold closing or mold opening, respectively. The movable mold insert is provided with a runner communicable with the sprue, and at least one material receiving cavity communicable with the runner and corresponding to the at least molding cavity. The material receiving cavity has a modeling member fitted therein and a raised pressing frame formed therearound. A plurality of locating means is provided in between the fixed and the movable mold insert. The ejector pin unit includes a main ejector pin and at least one cutting ejector pin. The cutting ejector pin is located below and corresponding to the material receiving cavity, and is upward movable to a height beyond a point at where the material receiving cavity communicates with the runner; and the main ejector pin is upward movable to push against the runner. 
         [0010]    The decorative film is sandwiched in between the fixed and the movable mold insert to cover the at least one molding cavity and the at least one material receiving cavity, and is provided with a material passing opening corresponding to the sprue and a plurality of locating holes corresponding to the locating means. According to an embodiment of the present invention, the decorative film includes a release layer, a cured layer, at least one ink layer and an adhesive layer, which are sequentially arranged from top to bottom. The release layer is provided for contacting with the fixed mold insert, and the adhesive layer for contacting with the movable mold insert. 
         [0011]    Another object of the present invention is to provide a method for manufacturing product with decorative patterns, so as to simplify the process for forming a product with a decorated external surface and to reduce the manufacturing time, labor and material costs of the product, enabling the product to be more competitive in the market. 
         [0012]    To achieve the above and other objects, the method for manufacturing product with decorative patterns according to the present invention includes the following steps: 
         [0013]    separating a movable mold base from a fixed mold base, and placing a decorative film between the two mold bases; 
         [0014]    closing the movable mold base to the fixed mold base, so as to sandwich the decorative film in between the two mold bases; 
         [0015]    injecting a plastic material into the fixed mold base, so that the plastic material flows through a runner provided on the movable mold base into at least one material receiving cavity, which is also provided on the movable mold base; 
         [0016]    allowing the plastic material to cure in the runner and the material receiving cavity to form a half-finished product with the decorative film attached thereto; 
         [0017]    separating the movable mold base from the fixed mold base, and actuating an ejector pin unit fitted in the movable mold base to cut the half-finished product from the plastic material cured in the runner while pushing the half-finished product upward; and 
         [0018]    removing the half-finished product from the movable mold base and peeling off a release layer of the decorative film, so as to obtain a finished product having decorative patterns shown on a surface thereof. 
         [0019]    In a preferred embodiment, the ejector pin unit includes at least one cutting ejector pin and a main ejector pin. The cutting ejector pin functions to cut the half-finished product from the cured plastic material in the runner, and the main ejector pin functions to upward push against the whole cured plastic material. In addition, a plurality of locating means is further provided in between a fixed mold insert fitted in the fixed mold base and a movable mold insert fitted in the movable mold base, and the decorative film is provided with a plurality of locating holes corresponding to the locating means, so that the decorative film can be accurately placed in between the fixed and movable mold bases. 
         [0020]    The present invention is characterized in forming the runner on the movable mold insert and placing the decorative film in between the fixed and the movable mold insert. In this manner, the decorative film is directly incorporated with the injected plastic material when the latter is molded in the mold, and the steps for manufacturing product with decorative patterns can be simplified. Further, the cutting ejector pin in the ejector pin unit automatically cuts the half-finished product from the cured plastic material in the runner when the ejector pin unit is upward moved to eject the half-finished product from the movable mold insert. Therefore, the step of manually cutting the half-finished product from the runner as needed in the conventional in-mold decoration technology is saved to effectively reduce the labor cost and increase the yield rate of the product. Moreover, since customized patterns can be produced on the decorative film, the product manufactured with the apparatus and the method of the present invention can have varied and abrasion-resistant surface patterns. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein 
           [0022]      FIGS. 1A to 1D  illustrate the manufacturing process of a conventional technology of in-mold decoration by roller; 
           [0023]      FIG. 2  is a vertical sectional view of an apparatus according to a preferred embodiment of the present invention for manufacturing product with decorative patterns, with a fixed and a movable mold base of the apparatus closed to each other; 
           [0024]      FIG. 3  is a partially enlarged view of  FIG. 2 ; 
           [0025]      FIG. 4  is a bottom plan view of a fixed mold insert for the apparatus of the present invention; 
           [0026]      FIG. 5  is a top plan view of a movable mold insert for the apparatus of the present invention; 
           [0027]      FIG. 6  is a vertical sectional view of the movable mold insert of  FIG. 5 ; 
           [0028]      FIG. 7  is a vertical sectional view showing the fixed and the movable mold insert for the present invention when the fixed and movable mold bases are closed to each other; 
           [0029]      FIG. 8A  is a perspective view of a decorative film for the present invention; 
           [0030]      FIG. 8B  is a sectional view of the decorative film of  FIG. 8A ; 
           [0031]      FIG. 9  is a flowchart showing the steps included in a method according to the present invention for manufacturing product with decorative patterns; and 
           [0032]      FIGS. 10A to 10G  pictorially illustrate the steps of the method according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0033]    The present invention will now be described with a preferred embodiment thereof and with reference to the accompanying drawings. 
         [0034]    Please refer to  FIG. 2 . An apparatus according to a preferred embodiment of the present invention for manufacturing product with decorative patterns includes a fixed mold mechanism  1 , a movable mold mechanism  2 , and a decorative film  3 . The fixed mold mechanism  1  includes a fixed mold base  10 , a fixed mold insert  11  set in the fixed mold base  10 , a top clamp plate  12 , and a locating ring  13  provided on the top clamp plate  12 . 
         [0035]    The movable mold mechanism  2  includes a movable mold base  20 , a movable mold insert  21  fitted in the movable mold base  20 , an ejector-pin support plate assembly  23  centered in a space below the movable mold base  20  and consisting of two superposed plates, namely, an upper ejector-pin support plate  231  and a lower ejector-pin support plate  232 , for supporting an ejector pin unit  22  thereon, two spacer blocks  24  separately located below two opposite lateral sides of the movable mold base  20  and each having a bottom flush with that of the lower ejector-pin support plate  232 , and a bottom clamp plate  25  mounted to the bottoms of the spacer blocks  24  and the lower ejector-pin support plate  232 . 
         [0036]    The ejector pin unit  22  includes at least one cutting ejector pin  221  and a main ejector pin  222 , all of which are pressed at their lower ends against a top of the lower ejector-pin support plate  232  and upward extended from a lower inner bottom of the upper ejector-pin support plate  231  through the movable mold base  20  into the movable mold insert  21 . 
         [0037]    As can be seen in  FIG. 3 , which is a partially enlarged view of  FIG. 2 , the decorative film  3  is sandwiched between the fixed mold mechanism  1  and the movable mold mechanism  2 , and is held in place by between two contact surfaces of the fixed mold insert  11  and the movable mold insert  21 . 
         [0038]    Please refer to  FIGS. 2 and 4 . On the fixed mold insert  11 , there is formed of a sprue  111  and at least one molding cavity  112 . The sprue  111  is centered on the fixed mold insert  11 , and is extended from a material entrance side  113  to an opposite processing side  114  of the fixed mold insert  11 . And, the molding cavity  112  is formed on the processing side  114 . 
         [0039]    Please refer to  FIGS. 5 and 6 . The movable mold insert  21  has a processing side  211  for contacting with the fixed mold insert  11 . On the processing side  211 , a runner  212  and at least one material receiving cavity  213  are formed. The material receiving cavity  213  is corresponding to the molding cavity  112  in number and position. The runner  212  is communicable with the sprue  111  and the material receiving cavity  213 . The material receiving cavity  213  has a raised pressing frame  214  formed therearound. When the fixed and the movable mold mechanism  1 ,  2  are closed to each other, the pressing frame  214  is pressed against the decorative film  3 , preventing the decorative film  3  from getting wrinkles to adversely lower the yield rate of finished products. 
         [0040]    The runner  212  includes a main runner portion  212   a  and a branch runner portion  212   b.  Further, the material receiving cavity  213  includes a first mold cavity  213   a,  which is communicable with the branch runner portion  212   b,  and a second mold cavity  213   b,  which is aligned with the corresponding molding cavity  112  and communicable with the first mold cavity  213   a  of the same material receiving cavity  213 . As can be seen in  FIGS. 2 and 3 , the at least one cutting ejector pin  221  is brought to extend a length of its top portion into the first mold cavity  213   a.  It is noted the top portion of the cutting ejector pin  221  in the first mold cavity  213   a  is upwardly moved to a height beyond a point at where the branch runner portion  212   b  communicates with the first mold cavity  213   a,  such that cured plastic material connected to between the first mold cavity  213   a  and the branch runner portion  212   b  is cut open by the upward moved cutting ejector pin  221 . And, as shown in  FIG. 2 , the main ejector pin  222  can be brought to press a top portion thereof against a bottom center of the runner  212  on the movable mold insert  21  for pushing and separating an integral body of the cured plastic material and the decorative film  3  out of the movable mold insert  21 . 
         [0041]    In the second mold cavity  213   b,  there is provided a modeling member  215  for changing an external shape of a finished product  51 . In the illustrated preferred embodiment, the finished product  51  is a button, as shown in  FIG. 10G , and the modeling member  215  is a rod, which is so sized that an annular space  216  is formed in the second mold cavity  213   b  around the rod  215 , allowing the plastic material flowed into and molded in the annular space  216  to form a sleeve. 
         [0042]    However, it is understood the finished product shaped into a button is only illustrative and not intended to limit the present invention in any way. It is also understood the modeling member  215  can be varied in configuration and in its position in the second mold cavity  213   b  to enable formation of finished products of different sizes and shapes. 
         [0043]    Please refer to  FIG. 7 . For the decorative film  3  to be precisely laid on the top of the movable mold insert  21 , the fixed and the movable mold insert  11 ,  21  are provided at corresponding positions with internally threaded holes  14 ,  26 , respectively, and a screw rod (not shown) can be screwed into each pair of two corresponding threaded holes  14 ,  26  to form a locating means. However, it is understood the locating means formed of the threaded holes and the screw rod are only illustrative and not intended to limit the present invention in any way. 
         [0044]      FIGS. 8A and 8B  are perspective and sectional views, respectively, of the decorative film  3 . As shown, the decorative film  3  is provided with a material passing opening  30  corresponding to the sprue  111  and a plurality of locating holes  31  corresponding to the locating means formed of the threaded holes  14 ,  26  and the screw rods. The decorative film  3  includes several layers sequentially arranged from top to bottom, namely, a release layer  32 , a cured layer  33 , at least one ink layer  34  and an adhesive layer  35 . The release layer  32  is provided for contacting with the fixed mold insert  11 , and the adhesive layer  35  for contacting with the movable mold insert  21 . The release layer  32  can be easily peeled off from the decorative film attached to the surface of a half-finished product  50  as that shown in  FIG. 10F . The cured layer  33  serves to protect the ink on the ink layer  34 . And, the ink layer  34  can be manufactured to provide different decorative patterns according to individual users&#39; requirement. The adhesive layer  35  is provided for contacting with the movable mold insert  21 , so that the decorative film  3  is stably adhered to the movable mold insert  21 . 
         [0045]    The present invention also provides a method for manufacturing product with decorative patterns, and  FIG. 9  is a flowchart showing the steps included in the method of the present invention. The steps include: 
         [0046]    separating a movable mold base from a fixed mold base, and placing a decorative film between the two mold bases; 
         [0047]    closing the movable mold base to the fixed mold base, so as to sandwich the decorative film in between the two mold bases; 
         [0048]    injecting a plastic material into the fixed mold base, so that the plastic material flows through a runner provided on the movable mold base into at least one material receiving cavity, which is also provided on the movable mold base; 
         [0049]    allowing the plastic material to cure in the runner and the material receiving cavity to form a half-finished product with the decorative film attached thereto; and separating the movable mold base from the fixed mold base; 
         [0050]    actuating an ejector pin unit fitted in the movable mold base to cut the half-finished product from the cured plastic material in the runner while pushing the half-finished product upward; and 
         [0051]    removing the half-finished product from the movable mold base and peeling off a release layer of the decorative film, so as to obtain a finished product having decorative patterns shown on a surface thereof. 
         [0052]    Please refer to  FIGS. 10A to 10G  that pictorially illustrate the steps of the method according to the present invention in more details. In  FIG. 10 , it is shown a sheet of decorative film  3  is placed between the fixed and the movable mold mechanism  1 ,  2  when the two mold mechanisms are separated from each other, so that the decorative film  3  is located on the top of the movable mold insert  21  with the material passing opening  30  formed on the decorative film  3  aligned with the sprue  111  formed on the fixed mold insert  11  and the runner  212  formed on the movable mold insert  21 . In addition, the locating holes  31  formed on the decorative film  3  are correspondingly fitted around the locating means provided in between the fixed and the movable mold insert  11 ,  21 . 
         [0053]    In  FIG. 10B , the movable mold mechanism  2  is moved upward to contact with the fixed mold base  10  and thereby sandwich the decorative film  3  in between the fixed and the movable mold insert  11 ,  21 . Meanwhile, the locating means are tightened to close the movable mold base  20  to the fixed mold base  10 . 
         [0054]    In  FIG. 10C , a plastic material  4  is injected into the runner  212  on the movable mold base  20  via the sprue  111  on the fixed mold base  10 . Then, allow the plastic material  4  to flow through the runner  212  into the at least one material receiving cavity  213  on the movable mold insert  21  and the at least one molding cavity  112  on the fixed mold insert  11 . When the plastic material  4  finally fills up all the spaces in the runner  212 , the material receiving cavity  213  and the molding cavity  112 , a half-finished product  50  can be formed. 
         [0055]    In  FIG. 10D , the half-finished product  50  is cooled and shaped, and the movable mold base  20  is separated from the fixed mold base  10  with the half-finished product  50  remaining on the movable mold insert  21 . 
         [0056]    In  FIG. 10E , the ejector-pin support plate assembly  23  is actuated by a push force from a knockout structure of a molding machine (not shown), so as to move the ejector pin unit  22  upward. The cutting ejector pin  221  is aligned with the half-finished product  50  in the material receiving cavity  213  and function to cut the half-finished product  50  from the cured plastic material in the runner  212  while the main ejector pin  222  synchronously upwardly pushes against an integral body of the cured plastic material  4  in the runner  212 , the material receiving cavity  213  and the molding cavity  112 , so that the half-finished product  50  is pushed out of the movable mold base  20  to complete the ejection step. 
         [0057]    In  FIG. 10F , the half-finished product  50  along with the decorative film  3  attached thereto is removed from the movable mold insert  21 . As can be seen in  FIG. 10F , the half-finished product  50  includes three sections, namely, a main runner section  50   a,  a branch runner section  50   b,  and a molded body  50   c.  The main runner section  50   a  and the branch runner section  50   b  are shaped corresponding to the main runner portion  212   a  and the branch runner portion  212   b  of the runner  212 , respectively. The molded body  50   c  has already been separated from the branch runner section  50   b  by the cutting ejector pin  221  in a previous step. 
         [0058]    In  FIG. 10G , the release layer  32  of the decorative film  3  is peeled off from the molded body  50   c  to obtain a finished product  51  having a decorative layer formed thereon. More specifically, the release layer  32  of the decorative film  3  can be easily peeled off from the half-finished product  50 ; and the finished product  51  is the molded body  50   c  of the half-finished product  50  with the release layer  32  removed therefrom to show the decorative patterns provided by the ink layer  34  of the decorative film  3 . 
         [0059]    The present invention has been described with a preferred embodiment thereof and it is understood that many changes and modifications in the described embodiment can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.