Abstract:
A method for forming a conformal fluid circulating passage in a mold includes providing a mold including a molding surface with an open passage thereon, the depth of the passage substantially conforming to the contour of the molding surface, the passage defining a plurality of open fluid channels including a first channel, a second channel downstream of the first channel and a third channel downstream of the second channel; and wherein each fluid channel defines a centerline that extends from the bottom of the open passage to the molding surface and a channel longitudinal centerline, and the method includes maintaining a common distance between the longitudinal centerlines and the molding surface and between the centerlines of adjacent channels.

Description:
BACKGROUND 
       [0001]    Various types of part molding are known. For example, plastic parts are commonly produced by injection molding and other molding techniques. Of particular interest here are those molding techniques wherein mold temperature must be controlled, such as by cooling to account for heat buildup from the injection or other introduction thereto of molten molding material (e.g., molten plastic). 
         [0002]    Commonly, mold cooling has been accomplished by boring a series of interconnected cooling channels into the mold and circulating a cooling fluid, such as water, through the cooling channels. Such cooling channels are frequently bored into a mold from a rear (mounting) side of a mold, but connecting channels may also emanate from other surfaces as well. Aside from an inlet(s) and outlet(s), openings to the outside of the mold are normally plugged to prevent unintended leakage of cooling fluid. 
         [0003]    While this technique may be generally effective at reducing overall average mold temperature, it is not without problems. One such problem is the non-uniform cooling that typically results. More particularly, the known technique of circulating cooling fluid through bored cooling channels frequently results in a greater cooling of certain mold parts than others. Consequently, a mold cooled in this manner may have temperature disparities that can negatively affect part cycle times, part quality, etc. Another problem with this known mold cooling technique is its inability to circulate cooling fluid near the actual molding surface of a mold having a contoured shape, at least not in a uniform manner. 
         [0004]    It is also known to provide conformal cooling passages within a mold for purposes of cooling the mold and/or a part produced by the mold. In particular, conformal cooling passages can be used to provide more uniform cooling of the part produced by the mold. Cooling passages are conformal when they generally conform to or follow the contour of the part produced by the mold and are disposed beneath the finished mold surface. When the part to be produced by the mold has a relatively complex shape, provisioning the mold with the conformal cooling passages can be difficult. 
       SUMMARY 
       [0005]    According to one aspect, a part producing mold having a cooling fluid passage defined therein comprises a channel defined in a mold surface of the mold by spaced apart lateral walls depending from the mold surface of the mold toward a closed bottom of the channel. A nonconsumable steel weld support is received in the channel and positioned adjacent the closed bottom. A bridge welded is across the channel onto and above the weld support and directly to the lateral walls for closing the channel and defining the fluid passage. 
         [0006]    According to another aspect, a part-producing mold having improved cooling capabilities, comprises at least one conformal cooling passage located subjacent to a molding surface to be cooled. The at least one conformal cooling passage is formed from a series of interconnected open channels placed in a molding surface of the mold, the channels substantially conforming to the contour of the molding surface, and a bridging weld located within each channel. The bridging weld comprises a series of connected weld beads. The bridging weld spans and seals each channel and is located at some distance from a bottom of each channel so as to form an enclosed cooling passage at the bottom thereof. A plurality of weld beads solidly fills a remaining volume of each channel above the bridging weld to close each channel. The weld beads at an open end of each channel are shaped to conform to the molding surface of the mold surrounding that channel. An inlet is associated with the at least one conformal cooling passage for receiving pressurized cooling fluid from a source thereof, and an outlet is associated with the at least one conformal cooling passage for expelling cooling fluid after the cooling fluid has passed through the at least one conformal cooling passage. According to a further aspect, a method for forming a conformal fluid circulating passage in a part-producing mold, comprises providing a mold including a molding surface with an open passage thereon, the depth of the passage substantially conforming to the contour of the molding surface, the passage defining a plurality of open fluid channels including a first channel, a second channel downstream of the first channel and a third channel downstream of the second channel, the bottom of the passage in at least a portion of the first channel has an elevation different than the bottom of the passage in at least a portion of one of the second channel and the third channel. Each fluid channel defines a centerline that extends from the bottom of the open passage to the molding surface and a channel longitudinal centerline, and the method includes maintaining a common distance between the longitudinal centerlines and the molding surface and between the centerlines of adjacent channels. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a top elevational view of a part producing mold having a fluid passage defined therein. 
           [0008]      FIG. 2  is a cross-sectional view taken along the line  2 - 2  of  FIG. 1  showing the fluid passage. 
           [0009]      FIGS. 3A-3E  are cross-sectional views illustrating a method for forming the fluid passage in the mold according to one exemplary embodiment. 
           [0010]      FIGS. 4A-4D  are cross-sectional views illustrating a method for forming the fluid passage in the mold according to an alternate exemplary embodiment. 
           [0011]      FIGS. 5A-5D  are cross-sectional views illustrating a method for forming the fluid passage in the mold according to another alternate exemplary embodiment. 
           [0012]      FIGS. 6A-6D  are cross-sectional views illustrating a method for forming the fluid passage in the mold according to yet another alternate exemplary embodiment. 
           [0013]      FIG. 7  is a top elevational view of a part-producing mold having a circuitous fluid passage defined therein according to yet another alternate exemplary embodiment. 
           [0014]      FIG. 8  is a cross-sectional view taken along line  8 - 8  of  FIG. 7 , depicting a number of open channels cut into the molding surface of the mold during one step of a method of the present invention, so as to form the fluid passage of  FIG. 7 . 
           [0015]      FIG. 9A  is an enlarged cross-sectional view of one of the open channels of  FIG. 8 , with a bridging weld placed therein in a subsequent step to form an underlying enclosed fluid passage. 
           [0016]      FIG. 9B  is a cross-sectional view showing the previously open channel of  FIG. 9 a    fully filled to form a sealed fluid passage. 
           [0017]      FIG. 10  shows the mold of  FIG. 8  with the conformal fluid passage of  FIG. 7  fully formed therein after completion of a fluid passage forming method of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    With reference now to the drawings wherein the showings are for purposes of illustrating one or more exemplary embodiments and not for purposes of limiting same,  FIG. 1  is a plan view of a part producing mold  10  having a fluid passage  12  defined therein. Although the mold  10  and the fluid passage  12  can only be shown in two dimensions herein, it should be understood, and is more readily apparent from  FIG. 2  that the mold  10  would also generally have a contoured shape in a third dimension instead of the planar shape conveyed herein. That is, while the portion of the mold  10  overlying the fluid passage  12  may be planar, it is more likely to have at least some contour. As is known and understood by those skilled in the art, the fluid passage  12  can be a cooling fluid passage through which a coolant is directed for cooling the part producing mold  10  and/or a part (not shown) molded by the part producing mold  10 . In the illustrated embodiment, the fluid passage  12  follows a circuitous path through the part producing mold  10  from a coolant inlet  14  to a coolant outlet  16 . As is to be appreciated and understood by those skilled in the art, the particular path followed by the fluid passage  12  need not be limited to that shown. In particular, the path, size and spacing of the fluid passage  12  can vary as necessary to provide the desired cooling effect. Further, while only one fluid passage  12  is shown and described herein, it will be appreciated and understood that more than a single fluid passage could be provided. 
         [0019]    As shown in the illustrated embodiment, and with additional reference to  FIG. 2 , the fluid passage  12  is disposed below a molding surface  18  of the mold  10  and can generally follow a contour of the molding surface  18 . The molding surface  18  can be contoured, as shown in the illustrated embodiment. In the illustrated embodiment, the mold  10  is shown as a single mold half but it is to be appreciated that another mold half can be provided (though not shown herein) to close a mold cavity  20  as is known and understood by those skilled in the art. 
         [0020]    With further reference to  FIGS. 3A-3E , and as will be described in more detail below, the mold  10  having the fluid passage  12  defined therein can include a channel or open passage  30  defined in the molding surface  18  of the mold  10 , a weld support  32  received in the channel  30  and a bridge  34  welded across the channel  30  above the weld support  32  for closing the channel  30  and defining the fluid passage  12 . Additionally, the mold  10  can include a class A machined surface  36  including and extending across the molding surface  18  of the mold  10  and the bridge  34 . 
         [0021]    A method for forming the fluid passage  12  in the mold  10  will now be described according to an exemplary embodiment. In the method, the weld support  32  is installed in the channel  30  defined in the molding surface  18  of the mold  10  as shown in  FIG. 3A . After the weld support  32  is installed, the bridge  34  is welded across the channel  30  above the weld support  32  for closing the channel  30  as shown in  FIG. 3C . In the embodiment of  FIGS. 3A-3E , the weld support  32  is a nonconsumable weld support, though this is not required. Additionally, the weld support  32  of this embodiment can be a strip of rigid material (e.g., steel) that is installed in the channel. The weld support  32  can have one of a generally planar configuration or a curved configuration, and is shown having a generally planar configuration in the embodiment depicted in  FIGS. 3A-3E . 
         [0022]    Installing the weld support  32  in the channel  30  can include welding the weld support  32  within the channel  30  at a location spaced apart from a lower end  30   a  of the channel  30  and from the molding surface  18 . This welding of the weld support  32  within the channel  30  can include welding a first end edge  32   a  of the weld support  32  to a first lateral wall  40  defining the channel  30  and a second end edge  32   b  of the weld support  32  to a second lateral wall  42  defining the channel  30 . This step of welding the weld support  32  within the channel  30  (i.e., welding the first and second edge edges  32   a ,  32   b  to the first and second lateral walls  40 ,  42 ) precedes and is separate from the step of welding the bridge  34  across the channel  30  above the weld support  32  in the embodiment illustrated in  FIGS. 3A-3E . Thus, the weld support  32  is a separate and disparate element from the bridge  34  in the depicted embodiment. Welding of the weld support  32  within the channel  30  can be done using a conventional TIG welder such as the illustrated welder  44 , though other types of welders could be used if desired. Alternatively, no specific welding of the weld support  32  need be done and welding of the bridge  34  could commence after placement of the weld support  32  without a separate step of welding the weld support  32  in position. 
         [0023]    The channel  30  is defined by the spaced apart lateral walls  40 ,  42  that depend from the molding surface  18  of the mold  10 . The spaced apart lateral walls  40 ,  42  can be at least one of parallel with one another (e.g., as depicted in the embodiments of  FIGS. 5A-5D  and  FIGS. 6A-6D ) or angled so that lower ends thereof converge toward one another (e.g., as shown in the embodiment depicted in  FIGS. 3A-3E and 4A-4D ) or curved (embodiment not shown). In the embodiment of  FIGS. 3A-3E , the spaced apart lateral walls  40 ,  42  are angled and lower ends  40   a ,  42   a  of the spaced apart lateral walls  40 ,  42  converge toward one another but are spaced apart from the lower end  30   a  of the channel  30 . Additionally in the illustrated embodiment, spaced apart shoulders  46 ,  48  are defined adjacent to lower ends  40   a ,  42   a  of the spaced apart lateral walls  40 ,  42  and the shoulders  46 ,  48  are spaced apart from the lower end of the channel  30   a . The lower end  30   a  can depend from the shoulders  46 ,  48  and have a generally curved configuration that is U-shaped in the embodiment illustrated in  FIGS. 3A-3E . As shown, the weld support  32  can rest on the shoulders  46 ,  48 . That is, the shoulders  46 ,  48  can extend inwardly toward one another relative to the lateral walls  40 ,  42  and can define a dimension that is shorter than a dimension of the weld support  32  spanning the channel  30 . In particular, in the illustrated embodiment, the spaced apart shoulders  46 ,  48  are defined along the lateral walls  40 ,  42  defining the channel  30 . The spaced apart shoulders  46 ,  48  are spaced apart from the lower end  30   a  of the channel  30  and spaced apart from the molding surface  18  of the mold in a direction parallel with a depth of the channel (e.g., the depth dimension extending along the axis  50  shown in  FIG. 3A ). Also as shown, the spaced apart lateral walls  40 ,  42  can be angled at approximately 20 degrees relative to a depth of the channel  30  (i.e., the depth defined along the axis  50 ) in the illustrated embodiment, though this is not required. 
         [0024]    The step of welding the bridge  34  across the channel  30  above the weld support  32  for closing the channel  30  is shown in progress in  FIG. 3C . Particularly, welding the bridge  34  across the channel  30  can include filling a cavity  52  defined between the weld support  32  and the molding surface  18  of the mold with a fill material  54 . In the illustrated embodiment, the fill material  54  is weld deposit material from the welder  44  that is incrementally deposited to form the bridge  34  via filling the cavity  52 . Filling the cavity  52  can include filling an entirety of the cavity and can further include filling the cavity  52  with the fill material  54  beyond the molding surface  18  of the mold as shown in  FIG. 3D . That is, the fill material  34  can be deposited within the cavity  30  above the weld support  32  so that the fill material  54  completely fills the cavity  52  and overflows from the cavity  52  so as to extend upward beyond the molding surface  18  of the mold  10 . Such filling can ensure complete filling of the cavity  52  without any voids. It is to be appreciated by those skilled in the art that the step of welding the bridge  34  can be at least one of robotically welded or manually welded. For example, a 3-D welding process, such as a TIG, MIG, Stick or GAS welding process can be used to deposit the fill material  54  within each channel  30 . 
         [0025]    Thereafter, the fill material  54  can be reduced, particularly the fill material  54  filled beyond the surface of the mold  18  can be reduced, so that an upper surface  54   a  of the fill material  54  is contiguous with the molding surface  18 . In one embodiment, such reduction of the fill material  54  is obtained by machining the fill material  54  until a class A machined surface  36  extends from the molding surface  18  of the mold  10  across the bridge  54  as shown in  FIG. 3E . The result, as shown in  FIG. 3E , is a closed fluid passage  12  defined by the weld support  32 , and the bridge  34  both disposed above the fluid passage  12  and integrated as part of the mold  10  via the welding processes discussed hereinabove. 
         [0026]    Optionally, the method described in  FIGS. 3A-3E  can include cutting the channel  30  into the molding surface  18  of the mold  10  before installing the weld support  32  and welding the bridge  34 , though this is not required. In particular, the mold  10  can be provided with the channel  30  already defined therein so that the method need not require the step of cutting the channel  30  into the molding surface  18  of the mold  10 . In one embodiment, though again not required, the method can include forming the mold  10  and the molding surface  18  of the mold  10  with the channel  30  by at least one of casting the mold  10 , molding the mold  10  or welding the mold  20 , techniques that are known and understood by those skilled in the art. 
         [0027]    With reference now to  FIGS. 4A-4D , a method for forming the fluid passage  12  in the mold  10  will be described according to an alternate exemplary embodiment. The method of  FIGS. 4A-4D  can be the same or similar to the method of  FIGS. 3A-3E  except as indicated hereinbelow and thus like reference numbers will be used to identify like elements and like reference numbers with the addition of a prime symbol (C) will be used to identify corresponding elements that vary between the embodiments. Like the method of  FIGS. 3A-3E , the method of  FIGS. 4A-4D  can include installing a weld support  32 ′ in the channel  30  defined in the molding surface  18  of the mold  10  and can include welding a bridge  34 ′ across the channel  30  above the weld support  32 ′ for closing the channel  30 . Details of the channel  30  in  FIGS. 4A-4D  can be as described in connection with the channel  30  of  FIGS. 3A-3E . 
         [0028]    Unlike the weld support  32 , the weld support  32 ′ has a generally curved configuration. In particular, the weld support  32 ′ can have a tubular configuration for defining the fluid passage  12  with a generally circular cross-section. As shown, the curvature of the tubular weld support  32 ′ can match the curvature of the lower end  30   a  of the channel  30  so that the weld support  32 ′ can be complementarily received within the channel  30  against the lower end of  30   a  in tight fitting arrangement as depicted in  FIG. 4B . Accordingly, installing the weld support  32 ′ in the channel  30  defined in the molding surface  18  of the mold  10  involves positioning the weld support  32 ′ against the lower end  30   a  of the channel  30  as shown in  FIGS. 4A and 4B . Due to the complementary fit, no welding of the weld support  32 ′ need be done as discussed above in connection with the weld support  32 . Instead, once the weld support  32 ′ is in position, the bridge  34 ′ can be welded across the channel  30  above the weld support  32 ′ for closing the channel  30 . Such welding of the bridge  34 ′ can be as described hereinabove in connection with the bridge  34  of  FIGS. 3A-3E . That is, welder  44  can be used to deposit a fill material  54  (e.g., weld material) within cavity  52 ′ defined between the weld support  32 ′ and the molding surface  18  of the mold  10 . 
         [0029]    Like the method of  FIGS. 3A-3E , welding the bridge  34 ′ can include fully filling the cavity  52 ′ with the fill material  54  and can further include filling the cavity  52 ′ with the fill material  54  beyond the molding surface  18  of the mold as shown in  FIG. 4C . Thereafter, the fill material  54  filled beyond the molding surface  18  of the mold  10  can be reduced so that the upper surface  54   a  of the fill material  54  is contiguous with the molding surface  18  of the mold  10  as shown in  FIG. 4D . As discussed above, this can include machining the fill material  54  to create a class A machined surface  36 ′. 
         [0030]    In one embodiment, the weld support  32 ′ is a consumable weld support. In particular, the weld support  32 ′ can be consumed after the bridge  54  is welded across the channel  30  above the weld support  32 ′ so that the weld support  32 ′ no longer occupies any space within the mold  10 . In one embodiment, the weld support  32 ′ is a consumable weld support that is dissolved after welding the bridge  54  across the channel  30 . Such dissolving of the weld support  32 ′ can include flushing a dissolving material (e.g., water) through the fluid passage  12  to dissolve and remove the weld support  32 ′ from the mold  10 . In one embodiment, the consumable weld support  32 ′ is formed from a semi-solid paste derived from a borax or sulfur based slurry, though other compositions could be used. 
         [0031]    With reference now to  FIGS. 5A-5D , another method for forming the fluid passage in a mold will be described. The method depicted in  FIGS. 5A-5D  can be the same as either of the methods of  FIGS. 3A-3E  or  FIGS. 4A-4D  except as indicated below. Like elements are shown in  FIGS. 5A-5D  with like reference numbers and corresponding elements are shown with like reference numbers with the addition of a prime symbol. In general, the method of  FIGS. 5A-5D  is the same as the previously described methods in that a weld support  32 ″ is installed in a channel  30 ′ defined in a surface  18 ′ of a mold  10 ′ and bridge  34 ″ is welded across the channel  30 ′ above the weld support  32 ″ for closing the channel  30 ′. 
         [0032]    As shown, the weld support  32 ″ is a strip of rigid material (e.g., steel) and has a curved configuration. Unlike the weld support  32 ′, however, the weld support  32 ″ is not a tubular element but is a half-curved element. Also as shown, spaced apart lateral walls  40 ′,  42 ′ are generally parallel to one another (i.e., are not angled relative to one another); however, it should be appreciated that the lateral walls  40 ′,  42 ′ can be angled relative to one another with the weld support  32 ″ being supported on shoulders of the lateral walls  40 ′,  42 ′ as described above. In the method of  FIGS. 5A-5D , the weld support  32 ″ is installed in the channel  30  at a location spaced apart from a lower end  30   a ′ of the channel  30 ′ and from the molding surface  18 ′, a concave side of the weld support  32 ″ facing toward the lower end  30   a ′ of the channel  30 ′ and a convex side of the weld support  32 ″ facing away from the lower end  30   a ′ of the channel  30 ′. As depicted, the convex side of the weld support  32 ″ defines a substantially circular shape with the lower end  30   a ′ of the channel  30 ′. The welder  44  can deposit fill material  54  (e.g., weld material) above the weld support  32 ″ to fill a cavity  52 ″ defined between the weld support  32 ″ and the molding surface  18 ′ of the mold  10 ′ (see  FIG. 5B ). As with the earlier described methods, the fill material  54  can completely fill the cavity  52 ″ and extend beyond the molding surface  18 ′ of the mold  10 ′ as shown in  FIG. 5C . Thereafter, the fill material  54  can be reduced so that an upper surface  54   a  of the fill material  54  is contiguous with the molding surface  18 ′ of the mold  10 ′ as shown in  FIG. 5D . 
         [0033]      FIGS. 6A-6D  illustrate yet another method for forming a fluid passage in a mold. The method of  FIGS. 6A-6D  can be the same as the method of  FIGS. 5A-5D  with the exception that the weld support  32 ″ is replaced by the weld support  32 ′ described in connection with the method of  FIGS. 4A-4D . As shown in  FIG. 6A , the weld support  32 ′ can be installed within the channel  30 ′ in a complementary relation. That is, the weld support  32 ′ can complementarily fit against the lower end  30   a ′ of the channel  30 ′ as shown in  FIG. 6B . Then, with continued reference to  FIG. 6B , the welder  44  can begin depositing fill material (e.g., weld material)  54  in the cavity  52 ″ disposed between the weld support  32 ′ and the molding surface  18 ′ of the mold  10 ′. The fill material  54  can continue to be deposited until the cavity  52 ″ is completely filled and can be filled so as to extend beyond the molding surface  18 ′ of the mold  10 ′ as shown in  FIG. 6C . Thereafter, the fill material  54  extending beyond the molding surface  18 ′ can be reduced so that upper surface  54   a  of the fill material  54  is contiguous with the molding surface  18 ′ of the mold  10 ′. Optionally, the weld support  32 ′ can be a consumable weld support as described hereinabove and therefore can be dissolved as shown in  FIG. 6D  so as to no longer occupy space within the mold  10 ′. 
         [0034]    According to the methods described herein, a method of forming a fluid passage in a mold is described that includes providing a molding surface with a channel having a closed bottom and an opening. The method further includes installing a weld support between a first wall and a second wall of the channel, wherein the weld support is positioned below the opening. Additionally, the method includes welding a bridge above the weld support between the first wall and the second wall of the channel, wherein the bridge is positioned below the opening to define the fluid passage. Providing the molding surface with a channel can optionally include at least one of cutting the channel into the mold surface, casting the mold with a channel defined in the mold surface, molding the mold with a channel defined in the mold surface, or welding the mold with the channel defined in the mold surface, though this is not required and the method can presume that a mold is already provisioned with the channel defined therein. 
         [0035]    As will be appreciated and understood by those skilled in the art, the methods described herein can provide a part producing mold (e.g., mold  10 ,  10 ′) having a fluid passage  12  defined therein that includes the channel  30  or  30 ′ defined in the molding surface  18  or  18 ′ of the mold  10  or  10 ′, weld support  32 ,  32 ′ or  32 ″ received in the channel  30  or  30 ′ and the bridge  34 ,  34 ′ welded across the channel  30  or  30 ′ above the weld support for closing the channel and defining the fluid passage  12 . The weld support can have one of a tubular configuration (weld support  32 ′), a planar strip configuration (weld support  32 ), or a curved strip configuration (weld support  32 ″). Also, the channel can be defined by spaced apart lateral walls depending from the surface of the mold and the spaced lateral walls can be at least one of parallel to one another (as shown in the methods of  FIGS. 5A-5D and 6A-6D ) or angled so that lower ends thereof converge towards one another (as shown in the methods of  FIGS. 3A-3E  and  FIGS. 4A-4D ) or can be curved (not shown herein). 
         [0036]    It should also be appreciated and understood that any of the features associated with the methods discussed herein can be mixed and matched with other of the methods described herein. For example, the weld support  32 ″ could be used in association with the shoulders  46 ,  48  depicted in  FIGS. 3A-3E  and/or the angled lateral walls  40 ,  42  depicted in  FIGS. 3A-3E . 
         [0037]    A plan view of an exemplary mold  100  having a sub-surface conformal cooling fluid passage  102  formed according to another aspect of the present disclosure is illustrated in  FIG. 7 . Again, although the mold  100  and the fluid passage  102  can only be shown in two dimensions herein, it should be understood, and is more readily apparent from  FIGS. 8-10 , that the mold would also generally have a contoured shape in a third dimension instead of the planar shape conveyed herein. That is, while the portion of the mold  100  overlying the fluid passage  102  may be planar, it is more likely to have at least some contour. 
         [0038]    As shown in  FIG. 7 , this particular fluid passage  102  follows a circuitous path through the mold  100 , from a coolant inlet  104  to a coolant outlet  106 . The particular path followed by the fluid passage  102  in this embodiment is provided for purposes of illustration only, and the present invention is not limited to any particular coolant passage layout. Similarly, the size and spacing of the fluid passage sections and the spacing therebetween may also vary as necessary to provide the desired cooling effect. Further, while only one fluid passage is shown and described herein, it should also be realized that a given portion of a mold may have a plurality of individual fluid passages. 
         [0039]    A method of creating the fluid passage  102  in the mold  100  is illustrated in  FIGS. 8-10 . As can be understood from a review of  FIG. 8 , a series of interconnected open passages or channels  110  are first cut into a molding surface  112  of the mold  100 . The channels  110  may be placed into the mold  100  by any of various techniques such as, for example, with a CNC machining apparatus, or by any of the other techniques mentioned above or otherwise known in the art. The channels  110  are of some predetermined width and extend to some predetermined depth below the molding surface, as would generally be calculated based on various physical characteristics of the mold, the material that will be molded, the degree of desired cooling, etc. 
         [0040]    As most clearly shown in  FIGS. 9A-9B , once the open channels  110  have been cut into the molding surface  112  of the mold h 100 , a 3-D welding process, such as a TIG, MIG, Stick or GAS welding process is used to produce a bridging weld  116  within each channel. For example, a robotic 3-D TIG welding process may be employed for this purpose. The 3-D welding process produces a series of small connected weld beads  118  that, together, span the width of the channel  110  and serve to seal the channel. While only three individual weld beads  118  are shown to bridge the channel  110  for purposes of clarity, it should be understood that a greater number of individual weld beads may be required in this regard. This bridging weld  116  is produced at some distance from the bottom of the channel  110  so as to enclose an open fluid passage  120  below the bridging weld. 
         [0041]    As illustrated in  FIG. 9B  and  FIG. 10 , once each bridging welding operation is complete, the open area of each channel  110  above the bridging weld  116  is filled. In this particular embodiment, the open area of each channel  110  above the bridging weld  116  is filled with welding material  124 . The use of other fillers may also be possible, such as, for example, epoxies. 
         [0042]    According to the method of the present invention, the channels cut into a mold will typically be filled with welding material  124  until the welding material extends at least slightly above the molding surface of the mold half. After the remainder of the channels  110  are appropriately filled with welding material  124 , the excess welding material is machined or otherwise shaped to the contour of the surrounding molding surface  112 , as is also shown in  FIG. 9B . The molding surface  112  can be subsequently provided with a Class A or similar finish that places the molding surface in condition to properly form a molded part. As can be best observed in  FIG. 10 , use of the aforementioned bridge weld  116  and subsequent filling of channels  110  cut into the molding surface  112  of the mold  100  allows for the production of a solid molding surface with an underlying open fluid passage  102 . 
         [0043]    A fluid passage produced in a mold by a method of the present disclosure may be connected to a source of coolant in a manner similar to that of other known mold cooling techniques. To that end, a fluid passage of the present disclosure may be constructed with an inlet end and an outlet end that are accessible from outside a mold. Such an exemplary construction is represented in  FIG. 7 . 
         [0044]    It can be understood that a method(s) of the present disclosure allows for the formation of sub-surface conformal cooling fluid passages in part-producing molds. These cooling passages are able to substantially conform to the contour of the molding surface of a given mold and may reside near to the molding surface so as to provide effective and efficient cooling thereof. Because a cooling fluid passage(s) produced substantially conforms to and resides near the molding surface, molding surface cooling is more uniformly and efficiently accomplished than with previously known techniques. 
         [0045]    The method(s) of the present disclosure may be used on various types of molds. For example, the method of the present invention may be used to produce conformal cooling passages in plastic injection molds through which cooling fluid is circulated. However, as described above, a method of the present disclosure may also be used to produce conformal cooling passages in a plastic compression, blow forming or vacuum forming mold, a metal casting die, and may be used with other temperature controlled manufacturing processes that employ cooperating preset forms to create an object from a provided supply of material. 
         [0046]    Further, although the present disclosure is directed at forming passages for circulating cooling fluid, it should be apparent that the method(s) of the present disclosure may also be employed to form conformal fluid circulating passages in a mold or die, regardless of whether the circulated fluid is used to cool or heat the mold/die. Therefore, although the method(s) of the present disclosure produces good results when used to produce conformal mold cooling passages for the cooling of molds, the present invention is not limited to mold cooling applications. 
         [0047]    It will also be appreciated that above-disclosed features and functions, or alternatives or varieties thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.