Patent Publication Number: US-2016229100-A1

Title: Cooling apparatus - using 3d printed micro porous material

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a PCT International Patent Application and claims benefit of U.S. Provisional Patent Application No. 61/886,938 filed Oct. 4, 2013. The disclosure of the above application is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a cooling assembly and method for manufacturing same. 
     BACKGROUND OF THE INVENTION 
     Standard injection molding arrangements and processes require long cycle times and have additional costs associated with secondary machinery and/or tooling. Generally, a part is molded within a cavity mold and then demolded. In one known attempt to improve prior standard methods the end of arm tooling is modified by using porous aluminum in order to try to demold injection molded parts more quickly. However, this attempt has been disadvantageous. Manufacturing of such a cooling tool for demolding is time consuming and extremely expensive. 
     Accordingly, a cooling assembly and method for making same is desired, which has integrated structural cooling features that reduce cycle time and also reduces tooling costs while increasing the speed of manufacturing of such cooling tooling. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a cooling apparatus and a process operable for making same. There is provided a cooling apparatus having a cooling box mounted directly to a demolding robot. The cooling box has integrated cooling and attachment features. There is provided a net fit between the cooling box, and the cavity inside of the molded part being manufactured, to allow the cooling cycle time to be reduced as the molded part finishes the cooling cycle in the end of arm tooling while the mold is closed and starts making the next molded part. At least one portion of the cooling box includes a three dimensional (3D) printed portion that is partly solid and partly micro porous. A vacuum is pulled through the walls of the cooling box allowing for part demolding and/or fixturing while cooling. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  is a cross sectional view of a cooling apparatus coupled to an exemplary demolding robot arm, in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     There is provided an end of arm cooling fixture that is microporous and allows for reduced injection molding cycle time, e.g., at least 20% reduction in cycle time, low cost tooling, and which is a three-dimensional (3D) printable part nest that is at least 60% porous stainless steel. 
     Referring generally to  FIG. 1 , there is provided a cooling apparatus, generally shown at  10 , having a cooling box, generally shown at  12 , that is operably configured for cooling and demolding a molded part, generally shown at  14 . The cooling box  12  is operably configured to be partially porous for improving demolding and cycle time. The cooling box  12  forms a housing, generally shown at  16 , with an internal chamber  18  or cavity. The housing  16  is partially solid and partially microporous. Preferably, the housing  16  is formed of a solid material except for at least one tool nest portion, generally shown at  20 , which is microporous. Most preferably, the cooling box  12 , e.g., housing portion  16 , is 60% solid and 40% microporous. The internal chamber  18  is fully enclosed by the housing  16  which has no gaps or openings except for a port provided for a vacuum line and, optionally, at least one extra vacuum port, as will be explained in greater detail below. 
     The solid portion, generally shown at  22 , of the housing  16  is integrally formed with the tool nest portion  20 , and is operably mounted directly to a demolding robot, generally shown at  24 , e.g., attachable to the robot using integrated robot attachment features such as threaded screw bosses, mounting plates, support ribs. The demolding robot  24  is connected to the rear of the housing  16  opposite the front where the tool nest  20  is located. Alternatively, the demolding robot  24  is connectable to the top or bottom of the cooling apparatus  10  depending on particular applications and working cell parameters. 
     The tool nest portion  20  has an integrally formed at least one curved surface portion  26  and at least one flange portion  30  operably configured to net fit to the molded part  14  to be demolded. At least one lip  34  extends from the flange portion  30  to contact the outer edge of the molded part  14  and is disposed between this outer edge and the solid portion  22  of the housing  16 . In a preferred embodiment, the curved surface  26  of the tool nest portion  20  substantially forms a hemisphere-shape or semicircle-like cross-section protruding into the internal chamber  18  and forms an open area to laterally receive the molded part  14  therein. When loaded into the cooling box  12 , the curve surface  26  generally follows the outer contour of the cavity section of the molded part  14 . When the cooling apparatus  10  retrieves the molded part  14 , a first outer surface  28  of the molded part  14  is selectively held in engagement with the curved surface  26  and a second outer surface  32  of the molded part  14  is selectively held in engagement with the flange portion  30 . Other cross-sections of the cooling apparatus  10  and all features are contemplated such that any structural features described herein will be implementable on any other molded part application/dimensions and suitably adjusted to net fit to the molded part to be demolded. 
     The cooling box  12  also has a plurality of integrated internal cooling ribs or fins  36  integrally formed with and extending from the tool nest portion  20  into the internal chamber  18  to improve the cooling cycle time to a predetermined temperature. The ribs  36  are preferably solid and extend linearly from the rear of the tool nest portion  20  toward the back of the cooling box  12 . The ribs  36  are spaced apart a predetermined operable amount and arranged parallel with one another. The ribs  36  also have various lengths. 
     At least one port  38  is operably provided in the housing  16  of the cooling box  12 . A vacuum line  40  is operably coupled thereto and in fluid communication with the internal chamber  18  for providing a vacuum through the cooling box. Preferably, there is provided integration of vacuum line attachment features for connection to the vacuum line  40 . The vacuum line  40  is coupled to a vacuum unit suitable to selectively remove a predetermined amount of air from the internal chamber  18  and create a predetermined pressure differential between the internal chamber  18  and atmosphere. A vacuum or vacuum force is generated operable to demold and cool the molded part  14  for a predetermined duration before the molded part  14  is released from the tool nest portion  20 . The cooling cycle is reduced since the molded part  14  finishes the cooling cycle in the cooling apparatus  10  while the mold is closed and starts making the next part(s). Optionally, at least one additional vacuum port, generally shown at  42 , is provided through the tool nest portion  20 . 
     Further, in accordance with the present invention 3D printing techniques and machinery are operably configured and adjusted to 3D “print” the end of arm cooling box  12  that is to be net fit to the cavity side of the molded part  14  to be demolded. A fully assembled form fitting cooling box  12  is provided. The cooling box  12  is mounted directly to the demolding robot  24  and is a net fit to the cavity inside of the molded part  14 . This allows the cooling cycle to be cut, e.g., by at least half, since the molded part  14  finishes the cooling cycle in the end of arm tooling (cooling box  12 ) while the mold is closed and starts making the next part. The printed cooling box  12  is solid and microporous, preferably, 60% solid and 40% microporous. This allows for improved demolding and cooling cycle times. Additional vacuum ports  42  can be formed into the cooling box, e.g., through the microporous tool nest portion  18  when printing the cooling box  12 , to additionally help aid in part demolding and fixturing while cooling a predetermined amount. 
     The embodiments of the present invention improve cycle time over standard injection molding processes, e.g., improvement in cycle time is at least 25%. The improved cycle time is made without substantial cost, which is a significant benefit over conventional systems/methods, and can help to eliminate secondary machinery or tooling. Using 3D printing allows for the manufacturing of an at least partially porous cooling box. The cost of “printing” and sintering such cooling tools is significantly lower. The speed of manufacturing cooling tools is significantly improved, e.g., builds cooling box  12  overnight. By way of non-limiting example, the build rate is at least ¼ inch per hour. Stainless steel powder, aluminum powder, magnesium powder and the like or other suitable materials can be used for the cooling box  12 . 
     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.