Patent Publication Number: US-7713044-B2

Title: Apparatus for producing a golf ball with deep dimples

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     The Present application is a continuation application of U.S. patent application Ser. No. 11/059,237, filed on Feb. 16, 2005, which is a continuation application of U.S. patent application Ser. No. 10/306,609, filed on Nov. 27, 2002, now U.S. Pat. No. 6,855,077, which claims priority upon U.S. Provisional Application No. 60/337,123, filed Dec. 4, 2001; U.S. Provisional Application No. 60/356,400, filed Feb. 11, 2002; and U.S. Provisional Application No. 60/422,247, filed Oct. 30, 2002. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention pertains to the art of making golf balls, and, more particularly, to golf balls having deep dimples. The present invention also relates to processes and apparatuses for forming multi-layer golf balls, and more particularly to processes and equipment for forming multi-layer golf balls having several deep dimples that extend through the outer cover layer to and/or into one or more layers or components thereunder. 
     2. Description of the Related Art 
     Golf balls are typically made by molding a core of elastomeric or polymeric material into a spheroid shape. A cover is then molded around the core. Sometimes, before the cover is molded about the core, an intermediate layer is molded about the core and the cover is then molded around the intermediate layer. The molding processes used for the cover and the intermediate layer are similar and usually involve either compression molding or injection molding. 
     In compression molding, the golf ball core is inserted into a central area of a two piece die and pre-sized sections of cover material are placed in each half of the die, which then clamps shut. The application of heat and pressure molds the cover material about the core. 
     Blends of polymeric materials have been used for modern golf ball covers because certain grades and combinations have offered certain levels of hardness to resist damage when the ball is hit with a club and elasticity to allow responsiveness to the hit. Some of these materials facilitate processing by compression molding, yet disadvantages have arisen. These disadvantages include the presence of seams in the cover, which occur where the pre-sized sections of cover material were joined, and long process cycle times which are required to heat the cover material and complete the molding process. 
     Injection molding of golf ball covers arose as a processing technique to overcome some of the disadvantages of compression molding. The process involves inserting a golf ball core into a die, closing the die and forcing a heated, viscous polymeric material into the die. The material is then cooled and the golf ball is removed from the die. Injection molding is well-suited for thermoplastic materials, but has limited application to some thermosetting polymers. However, certain types of these thermosetting polymers often exhibit the hardness and elasticity desired for a golf ball cover. Some of the most promising thermosetting materials are reactive, requiring two or more components to be mixed and rapidly transferred into a die before a polymerization reaction is complete. As a result, traditional injection molding techniques do not provide proper processing when applied to these materials. 
     Reaction injection molding is a processing technique used specifically for certain reactive thermosetting plastics. As mentioned above, by “reactive” it is meant that the polymer is formed from two or more components which react. Generally, the components, prior to reacting, exhibit relatively low viscosities. The low viscosities of the components allow the use of lower temperatures and pressures than those utilized in traditional injection molding. In reaction injection molding, the two or more components are combined and reacted to produce the final polymerized material. Mixing of these separate components is critical, a distinct difference from traditional injection molding. 
     The process of reaction injection molding a golf ball cover involves placing a golf ball core into a die, closing the die, injecting the reactive components into a mixing chamber where they combine, and transferring the combined material into the die. The mixing begins the polymerization reaction which is typically completed upon cooling of the cover material. 
     The present invention provides a new mold or die configuration and a new method of processing for reaction injection molding a golf ball cover or inner layer which promotes increased mixing of constituent materials, resulting in enhanced properties and the ability to explore the use of materials new to the golf ball art. 
     For certain applications it is desirable to produce a golf ball having a very thin cover layer. However, due to equipment limitations, it is often very difficult to mold a thin cover. Accordingly, it would be beneficial to provide an apparatus and technique for producing a relatively thin cover layer. 
     Moreover, retractable pins have been utilized to hold, or center, the core or core and mantle and/or cover layer(s) in place within an injection mold while molding an outer cover layer thereon. In such processes, the core or mantled ball is supported in the mold using retractable pins extending from the inner surface of the mold to the outer surface of the core or mantled ball. The pins in essence support the core or mantled ball while the cover layer is injected into the mold. Subsequently, the pins are retracted as the cover material fills the void between the core or mantle and the inner surface of the mold. 
     However, notwithstanding, the benefits produced through the use of the retractable pins, the pins sometimes produce centering difficulties and cosmetic problems (i.e. pin flash, pin marks, etc.) during retraction, which in turn require additional handling to produce a golf ball suitable for use and sale. Additionally, the lower the viscosity of the mantle and/or cover materials, the greater the tendency for the retractable pins to stick due to material accumulation, making it necessary to shut down and clean the molds routinely. Accordingly, it would be desirable to provide an apparatus and method for forming a cover layer on a golf ball without the use of retractable pins. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides, in a first aspect, a golf ball having a plurality of deep dimples defined along an outer surface of the golf ball. The golf ball comprises a core and a cover layer disposed about the core. The cover layer has an outer surface and a thickness and defines a collection of dimples along its outer surface. At least 1%, and more preferably at least 5%, of the dimples have a depth greater than the thickness of the cover layer, and thus extend through the cover layer. 
     In another aspect, the present invention provides a golf ball comprising a core and a cover layer disposed about the core. The cover layer has a thickness and defines at least two populations of dimples along an outer surface of the cover layer. A first population of dimples includes dimples having a depth greater than the thickness of the cover layer. The second population of dimples includes dimples having a depth less than the thickness of the cover layer. The first population of dimples constitutes at least a minority proportion of the total number of dimples defined along the outer surface of the cover layer. 
     In yet another aspect, the present invention provides a molding apparatus for forming a golf ball having a cover with a thickness and a plurality of dimples along its outer surface. The molding apparatus comprises a first molding component that defines a hemispherical first mold surface. The first mold surface has at least two populations of outwardly extending projections that form dimples. The populations differ from each other by the height of the projections. The molding apparatus also comprises a second molding component that defines a hemispherical second mold surface. The second mold surface has at least two populations of outwardly extending projections that form the noted dimples. The populations differ from each other by the height of the projections. The second molding component is adapted such that, upon engagement with the first molding component, a generally spherical molding chamber results from the first mold surface and the second mold surface. The molding apparatus also comprises provisions for receiving one or more flowable materials used for forming the golf ball and administering such materials into the molding chamber. At least one population of the outwardly extending projections of the first mold surface and at least one population of outwardly extending projections of the second mold surface have a projection height in the range of from about 0.005 inches to about 0.050 inches. 
     In a further aspect, the present invention provides a reaction injection molding apparatus for forming a golf ball core or intermediate ball assembly and an outer cover layer disposed about the core or ball assembly. The molding apparatus comprises a first mold defining a hemispherical first mold surface. The molding apparatus also comprises a second mold defining a hemispherical second mold surface. The first and second mold surfaces have a first population of raised regions that form dimples along the cover layer of the golf ball. The first and second mold surfaces also have a second population of raised regions each having a height greater than the thickness of the cover layer of the ball. The molding apparatus also comprises provisions for receiving two or more flowable reactants utilized for forming the outer cover layer. The second population of raised regions constitutes a minority proportion of the total number of dimples along the cover layer. 
     In yet another aspect, the present invention provides a process for producing a golf ball having a particular proportion of deep dimples along an outer surface of the ball. The process comprises providing a molding apparatus that defines a generally spherical molding chamber resulting from a molding surface having a first population of raised regions that form dimples in the golf ball, and a second population of raised regions that form deep dimples in the golf ball. The process also comprises a step of providing a flowable molding material to the molding apparatus. The process includes another step of positioning a core or intermediate ball assembly in the molding chamber. The process includes a further step of introducing the flowable molding material into the molding chamber between the core or intermediate ball assembly and the molding surface. The process comprises another step of hardening the flowable material to thereby form the golf ball. The second population of the raised regions constitutes at least 5% of the total number of dimples along the outer surface of the ball. 
     A further aspect of the invention is to provide equipment and methods for forming a golf ball having a dimpled cover that is thinner than traditional cover layers. 
     Another aspect of the invention is to provide equipment and methods for forming a golf ball having a plurality of dimples in an outer cover layer that extend to, and/or into, at least the next inner layer of the ball. 
     Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The following figures are not necessarily to scale, but are merely illustrative of the present invention. Specifically, the figures are for purposes of illustrating various aspects and preferred embodiments of the present invention and are not to be construed as limiting the invention described herein. 
         FIG. 1  is a perspective view revealing the components of a preferred embodiment golf ball in accordance with the present invention. 
         FIG. 2  is a perspective view of a preferred embodiment molding assembly in accordance with the present invention. 
         FIG. 3  is a planar view of a portion of the preferred embodiment molding assembly taken in the direction of line  3 - 3  in  FIG. 2 . 
         FIG. 4  is a planar view of a portion of the preferred embodiment molding assembly taken in the direction of line  4 - 4  in  FIG. 2 . 
         FIG. 5  is a detailed perspective view of a portion of the preferred embodiment molding assembly taken in the direction of line  5 - 5  in  FIG. 2 . This view illustrates a mix-promoting peanut after-mixer in accordance with the present invention. 
         FIG. 6  is a detailed view of the peanut after-mixer of the preferred embodiment molding assembly in accordance with the present invention. 
         FIG. 7  is a planar view of a portion of an alternative embodiment of the molding assembly in accordance with the present invention. 
         FIG. 8  is a planar view of a portion of an alternative embodiment of the molding assembly in accordance with the present invention. 
         FIG. 9  is a planar view of a portion of an alternative embodiment of the molding assembly in accordance with the present invention. 
         FIG. 10  is a flow chart illustrating a preferred embodiment process in accordance with the present invention. 
         FIG. 11  is a cross-sectional view of another preferred embodiment golf ball according to the present invention having a core and a single cover layer having dimples, wherein one or more of the dimples extends through the cover to and/or into the underlying core. 
         FIG. 12  is a diametrical cross-sectional view of the preferred embodiment golf ball illustrated in  FIG. 11 . 
         FIG. 13  is a cross-sectional view of another preferred embodiment golf ball according to the present invention having a core component and a cover component, wherein the cover component includes an inner cover layer and an outer cover layer having dimples formed therein, and wherein one or more of the dimples of the outer cover layer extends to and/or into the underlying inner cover layer. 
         FIG. 14  is a diametrical cross-sectional view of the preferred embodiment golf ball illustrated in  FIG. 13 . 
         FIG. 15  is a cross-sectional detail view of a portion of another preferred embodiment golf ball according to the present invention having a core and a cover illustrating a dual radius dimple that extends through the cover into the underlying core. 
         FIG. 16  is a cross-sectional detail view of a portion of another preferred embodiment golf ball according to the present invention having a core and a cover illustrating a dual radius dimple that extends through the outer cover layer to the outer surface of the core. 
         FIG. 17  is a cross-sectional detail view of a portion of another preferred embodiment golf ball according to the present invention having a core, an inner cover layer, and an outer cover layer, wherein the outer cover layer has a dual radius dimple that extends into the inner cover layer. 
         FIG. 18  is a cross-sectional detail view of a portion of another preferred embodiment golf ball according to the present invention having a core, an inner cover layer, and an outer cover layer illustrating a dual radius dimple that extends through the outer cover layer to the inner cover layer of the ball. 
         FIG. 19  is a schematic view of a preferred embodiment molding assembly and a golf ball core according to the present invention. 
         FIG. 20  is a process flow diagram which schematically depicts a reaction injection molding process according to the invention. 
         FIG. 21  schematically shows a preferred embodiment molding assembly for reaction injection molding a golf ball cover according to the invention. 
         FIG. 22  is a schematic process flow diagram illustrating a heat exchange circuit utilized for an isocyanate feed source. 
         FIG. 23  is a schematic process flow diagram illustrating a heat exchange circuit utilized for a polyol feed source. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention relates to equipment and methods for producing improved golf balls, particularly a golf ball comprising a cover disposed about a core in which the cover has one or more, preferably a plurality of, deep dimples or apertures that extend through the outer cover to and/or into one or more layers underneath. 
     The present invention also relates to equipment and methods for producing golf ball assemblies, i.e. cores having one or more mantle or inner cover layers disposed thereon, in which the core or ball assembly includes a plurality of deep dimples. The golf balls of the present invention, which can be of a standard or enlarged size, have a unique combination of cover thickness and dimple configuration. The present invention also relates to forming these golf balls, or at least certain components thereof, by reaction injection molding techniques. Such deep dimples extend through at least one cover layer to, and/or into, the underlying surface or component or layer. 
     With regard to dimple configuration or cross-sectional geometry, the present invention is based upon the identification of various particularly preferred characteristics as follows. Typically, for circular dimples, dimple diameter is used in characterizing dimple size rather than dimple circumference. The diameter of typical dimples may range from about 0.050 inches to about 0.250 inches. A preferred diameter of a typical dimple is about 0.150 inches. The deep dimples may have these same dimensions or may have dimensions as described in greater detail herein. As will be appreciated, circumference of a dimple can be calculated by multiplying the diameter times p. 
     The depth of typical dimples previously utilized in the trade may range from about 0.002 inches to about 0.020 inches or as much as 0.050 inches. Preferably, a depth of about 0.010 inches is preferred for typical or conventional dimples. It is preferred that the depth of a deep dimple as described herein is greater than the depth of a typical dimple. Most preferably, the deep dimples have a depth that is deeper than the depth of the typical dimples by at least 0.002 inches. 
     Specifically, depth of a dimple may be defined in at least two fashions. A first approach is to extend a chord from one side of a dimple to another side and then measure the maximum distance from that chord to the bottom of the dimple. This is referred to herein as a “chordal depth.” Alternatively, another approach is to extend an imaginary line corresponding to the curvature of the outer surface of the ball over the dimple whose depth is to be measured. This is referred to herein as a “periphery depth.” The latter format of dimple depth determination is used herein unless noted otherwise. 
     As described herein, the deep dimples included in the present invention are particularly useful when molding certain layers or components about cores or intermediate ball assemblies. The depth of a deep dimple as described herein may range from about 0.002 inches to about 0.140 inches, more preferably from about 0.002 inches to about 0.050 inches, and more preferably from about 0.005 inches to about 0.040 inches. Preferably, a total depth of about 0.025 inches is desired. It is most preferred that the depth of a deep dimple as described herein is greater than the depth of a typical dimple and extend to at least the outermost region of the mantle or core. Alternatively, the deep dimples preferably extend to the bottom of a matched set of dimples on the mantle or the core. The diameter of the deep dimples may be dissimilar, but preferably is the same as other dimples on a ball, and may range from about 0.025 inches to about 0.250 inches and more preferably from about 0.050 inches to about 0.200 inches. A preferred diameter is about 0.150 inches. Generally, depth is measured from the outer surface of a finished ball, unless stated otherwise. 
     In one embodiment, the present invention relates to an apparatus and technique for forming a golf ball comprising a core and a cover layer, wherein the cover layer provides dimples including one or more deep dimples that extend to or into the next inner layer or component. The cover may be a single layer or comprise multiple layers, such as two, three, four, five or more layers and the like. If the cover is a multi-layer cover, the dimples extend into at least the first inner cover layer, and may extend into a further inner cover layer, a mantle or intermediate layer, and/or the core. If the cover is a single layer, the deep dimples may extend into a mantle layer and/or the core. The cover layer(s) may be formed from any material suitable for use as a cover, including, but not limited to, ionomers, non-ionomers and blends of ionomers and non-ionomers. 
     In another embodiment, the present invention relates to an apparatus and technique for forming a golf ball comprising a core and a cover layer, wherein the cover layer provides dimples that extend to the core. The golf ball may optionally comprise a thin barrier coating between the core and the cover that limits the transition of moisture to the core. The barrier coating is preferably at least about 0.0001 inches thick. Preferably, the barrier layer is at least 0.003 inches thick. In a two-piece golf ball, a barrier coating is preferably provided between the core and the cover. 
     In a further embodiment, the present invention relates to equipment and processes for forming a golf ball having a plurality of dimples along its outer surface. In accordance with the present invention, one or more of these dimples are deep dimples that extend entirely through the cover layer of the ball, and to or into one or more underlying components or layers of the ball. For instance, for a golf ball comprising a core and a cover layer disposed about the core, the deep dimples preferably extend through the cover layer and to or into the core. If one or more layers such as an intermediate mantle layer are provided between the core and the cover layer, the deep dimples preferably extend through the cover layer and to or into one or more of those layers. The deep dimples may additionally extend into the core. 
     The deep dimples of the present invention may be spherical or non-spherical. Additionally, the portion of the deep dimple that extends to, or into the next inner layer or component may be the same or different size and/or shape as the outer portion of the dimple. 
     Turning now to the drawings, with reference to  FIG. 1 , a preferred embodiment golf ball  10  in accordance with the present invention is illustrated. The golf ball  10  includes a central core  12  which may be solid or liquid as known in the art. A cover  14  is surroundingly disposed about the central core  12 . An intermediate layer  16  may be present between the central core  12  and the cover  14 . The present invention primarily relates to the cover  14  and will be described with particular reference thereto, but it is also contemplated to apply to molding of the intermediate layer  16 . The preferred embodiment ball  10  includes one or more deep dimples  18  that extend through at least the cover layer  14 . The deep dimples  18  extend to, or through, the intermediate layer  16 . The deep dimples may further extend into the core  12 . It will be appreciated that in the event the core is liquid, the deep dimples will not extend to the core. 
     As noted, the present invention relates to various molding assemblies and techniques for forming a golf ball having one or more deep dimples along an outer surface of the golf ball. The deep dimples extend through the outermost cover layer of the ball, to or into or through one or more components underneath the outermost cover layer. As explained herein, the deep dimples result from one or more outwardly extending projections or protrusions that are provided in a molding chamber used for molding the final ball. The protrusions generally have a height greater than other raised regions along the molding surface that form conventional dimples along the ball exterior. 
     Turning now to  FIG. 2 , a perspective view of a preferred embodiment molding assembly in accordance with the current invention is shown. As previously noted, complete and timely mixing of two or more constituent materials is important when using a RIM process. The preferred embodiment molding assembly  20  provides such mixing as a result of its unique design and configuration. An injection machine, as known in the art, is connected to the preferred embodiment molding assembly  20  which comprises an upper half  22 A and a lower half  22 B. As will be appreciated, the upper and lower halves  22 A and  22 B are preferably formed from a metal or suitable material. A mixing chamber may, as known in the art, precede the molding assembly  20  if desired. In a further aspect of the present invention, the molding assembly  20  is utilized as follows. A core  12  (referring to  FIG. 1 ) is positioned within a central cavity formed from two hemispherical depressions  24 A and  24 B defined in opposing faces of the upper half and lower half  22 A and  22 B, respectively, of the molding assembly  20 . As will be appreciated, when the upper and lower halves  22 A and  22 B are closed, and the cavities  24 A and  24 B are aligned with each other, the resulting cavity has a spherical configuration. If the molding assembly is for molding a cover layer, each of the hemispherical cavities  24 A and  24 B defines a plurality of raised regions that, upon molding a cover layer therein, will result in corresponding dimples on the cover layer. 
     Each upper and lower half  22 A and  22 B of the preferred embodiment molding assembly  20  defines an adapter portion  26 A and  26 B to enable the molding assembly  20  to connect to other process equipment as mentioned above and leads to a material inlet channel  28 A and  28 B as illustrated in  FIG. 2 . As will be understood, upon closing the upper and lower halves  22 A and  22 B of the molding assembly  20 , the separate halves of adapter portion  26 A and  26 B are aligned with each other and create a material flow inlet within the molding assembly. And, each upper and lower half  22 A and  22 B of the assembly  20  further defines flow channels  28 A and  28 B,  30 A and  30 B and  32 A and  32 B which create a comprehensive flow channel within the molding assembly when the upper and lower halves  22 A and  22 B are closed. Specifically, the material flow inlet channel portion  28 A,  28 B receives the constituent materials from the adapter portion  26 A and  26 B and directs those materials to a turbulence-promoting portion of the channel  30 A,  30 B which is configured to form at least one fan gate. The upper and lower mold halves  22 A and  22 B include complimentary turbulence-promoting peanut after-mixer channel portions  30 A and  30 B, respectively. It will be appreciated that upon closing the upper and lower halves  22 A and  22 B of the molding assembly  20 , the channel portion  30 A and  30 B defines a region of the flow channel that is generally nonlinear and includes a plurality of bends and at least one branching intersection generally referred to herein as an after-mixer gate. Each after-mixer channel portion  30 A,  30 B is designed to direct material flow along an angular or tortuous path. As will be described in more detail below, when material reaches a terminus of angular flow in one plane of the flow channel in one half, the material flows in a transverse manner to a corresponding after-mixer channel portion in the opposing half. Thus, when the constituent materials arrive at the after-mixer defined by the channel portion  30 A and  30 B, turbulent flow is promoted, forcing the materials to continue to mix within the molding assembly  20 . This mixing within the molding assembly  20  provides for improved overall mixing of the constituent materials, thereby resulting in a more uniform and homogeneous composition for the cover  14 . 
     With continuing reference to  FIGS. 3 and 4 , views  3 - 3  and  4 - 4  from  FIG. 2 , respectively, are provided. These views illustrate additional details of the present invention as embodied in the mold upper and lower halves  22 A and  22 B. The material inlet channel  28 A and  28 B allows entry of the constituents which are subsequently directed through the mix-promoting channel portion  30 A and  30 B, which forms the after-mixer, then through the connecting channel portion  32 A and  32 B and to the fan gate portion  34 A and  34 B which leads into the cavity  24 A and  24 B. The final channel portion  34 A and  34 B may be defined in several forms extending to the cavity  24 A and  24 B, including corresponding or complimentary paths which may be closed ( 34 A) or open ( 34 B) and of straight, curved or angular ( 34 A,  34 B) shape. 
     With continuing reference to  FIGS. 3 and 4 , at least one protrusion  36  preferably extends into the central cavity  24 A and  24 B. This at least one protrusion extends from the molding surface into the molding cavity  24 A and  24 B and supports a golf ball core, such as core  12 , or intermediate ball assembly. The preferred dimensions, configuration, and orientation of the protrusion(s) are explained in greater detail herein. It is these protrusion(s) that form one or more deep dimple(s) in the outer surface of a golf ball and which relate to another aspect of the present invention. In typical injection molding, many retractable pins, often four, six or more, are used to centrally position and retain the core  12  in the molding cavity. It has been discovered that because of the reduced process pressure involved in RIM, fewer supporting structures are necessary in the molding assembly  20  to centrally locate the core  12  in the central cavity  24 A and  24 B. For example, only three protrusions  36  or less may be necessary per mold half. For some embodiments, it is preferred to utilize six protrusions per mold half. The use of fewer supporting structures reduces the cost of the tooling and reduces problems such as defacement and surface imperfections caused by retractable pins. The protrusions  36  are preferably provided at different locations in the molding assembly  20  and extend into different portions of the central cavity formed by the hemispherical cavities  24 A,  24 B. A channel leading from the cavity  24 A and  24 B may be provided as either a cavity venting channel or an overflow channel or dump well as known in the art. As shown in  FIG. 2 , a dump well  31 A,  31 B is provided in the corresponding molds. A dump well vent  33 A,  33 B provides communication between the dump well and mold exterior. A venting channel  29 A,  29 B is defined in the molds and provides communication between the central cavity  24 A,  24 B and the dump well. It will be appreciated that when the upper and lower halves  22 A and  22 B are closed, the respective portions of the channel align with one another to form the venting or overflow channel. 
     Turning now to  FIG. 5 , a perspective view of the molding assembly  20  illustrates the details of material flow and mixing provided by the current invention. The body halves  22 A and  22 B are shown in an open position, i.e., removed from one another, for purposes of illustration only. It will be appreciated that the material flow described below takes place when the halves  22 A and  22 B are closed. The adapter portion  26 A,  26 B leads to the inlet flow channel  28 A,  28 B which typically has a uniform circular cross section of  3608 . The flowing material proceeds along the inlet channel  28 A,  28 B until it arrives in a location approximately at a plane designated by line C-C. At this region, the material is forced to split apart by a branching intersection  38 A and  38 B. Each half of the branching intersection  38 A and  38 B is divergent, extending in a direction generally opposing the other half. For example, portion  38 A extends upward and  38 B extends downward relative to the inlet channel  28 A,  28 B as shown. Each half of the branching intersection  38 A and  38 B, in the illustrated embodiment, is semicircular, or about 1808 in curvature. The separated material flows along each half of the branching intersection  38 A and  38 B until it reaches a respective wall,  40 A and  40 B. 
     At each first wall  40 A and  40 B, the material can no longer continue to flow within the plane of the closed mold, i.e., the halves  22 A and  22 B being aligned with one another. To aid the present description it will be understood that in closing the mold, the upper half  22 A is oriented downward (referring to  FIG. 5 ) so that it is generally parallel with the lower half  22 B. The orientation of the halves  22 A and  22 B in such a closed configuration is referred to herein as lying in an x-y plane. As explained in greater detail herein, the configuration of the present invention after-mixer provides one or more flow regions that are transversely oriented to the x-y plane of the closed mold. Hence, these transverse regions are referred to as extending in a z direction. 
     Specifically, at the first wall  40 A the material flows from a point  1  in one half  22 A to a corresponding point  1  in the other half  22 B. Point  1  in half  22 B lies at the commencement of a first convergent portion  42 B. Likewise, at the first wall  40 B the material flows from a point  1  in one half  22 B to a corresponding point  1  in the other half  22 A. The point  1  in half  22 A lies at the commencement of a first convergent portion  42 A. The first convergent portion  42 A and  42 B brings the material to a first common area  44 A and  44 B. In the shown embodiment, each first convergent portion is parallel to each first diverging branching intersection to promote a smooth material transfer. For example, the portion  42 A is parallel to the portion  38 A, and the portion  42 B is parallel to the portion  38 B. 
     With continuing reference to  FIG. 5 , the flowing material arrives at the first common area  44 A and  44 B, which has a full circular, i.e., 360 degrees, cross section when the halves  22 A and  22 B are closed. Essentially, the previously separated material is rejoined in the first common area  44 A and  44 B. A second branching intersection  46 A and  46 B which is divergent then forces the material to split apart a second time and flow to each respective second wall  48 A and  48 B. As with the first wall  40 A and  40 B, the material, upon reaching the second wall  48 A and  48 B can no longer flow in an x-y plane and must instead move in a transverse z-direction. For example, at the wall  48 A, the material flows from a point “2 in one half  22 A to a corresponding point” 2 in the other half  22 B, which lies in a second convergent portion  50 B. The material reaching the wall  48 B flows from a point $2 in one half  22 B to a corresponding point $2 in the other half  22 A, which lies in a second convergent portion  50 A. 
     In the shown embodiment, each second convergent portion  50 A and  50 B, is parallel to each second diverging branching intersection  46 A and  46 B. For example, the portion  50 A is parallel to the portion  46 A and the portion  50 B is parallel to the portion  46 B. The second convergent portion  50 A and  50 B forces the material into a second common area  52 A and  52 B to once again rejoin the separated material. As with the first common area  44 A and  44 B, the second common area  52 A and  52 B has a full circular cross section. 
     After the common area  52 A and  52 B, a third branching intersection  54 A and  54 B again diverges, separating the material and conveying it in different directions. Upon reaching each respective third wall, i.e., the wall  56 A in the portion  54 A and the wall  56 B in the portion  54 B, the material is forced to again flow in a transverse, z-direction from the planar x-y direction. From a point  3  at the third wall  56 A in one half  22 A, the material flows to a corresponding point  3  in the other half  22 B, which lies in a third convergent portion  58 B. Correspondingly, from a point  3  at third wall  56 B in one half  22 B, the material flows to a corresponding point  3  in the other half  22 A, which is in a third convergent portion  58 A. 
     The turbulence-promoting after-mixer structure  30 A and  30 B ends with a third convergent portion  58 A and  58 B returning the separated material to the connecting flow channel  32 A and  32 B. The connecting channel  32 A and  32 B is a common, uniform circular channel having a curvature of 360 degrees. Once the material enters the connecting channel portion  32 A and  32 B, typical straight or curved smooth linear flow recommences. 
     By separating and recombining materials repeatedly as they flow, the present invention provides for increased mixing of constituent materials. Through the incorporation of split channels and transverse flow, mixing is encouraged and controlled while the flow remains uniform, reducing back flow or hanging-up of material, thereby reducing the degradation often involved in non-linear flow. Particular note is made of the angles of divergence and convergence of the after-mixer portions  38 A and  38 B,  42 A and  42 B,  46 A and  46 B,  50 A and  50 B,  54 A and  54 B and  58 A and  58 B, as each extends at the angle of about 30 degrees to 60 degrees from the centerline of the linear inlet flow channel  28 A,  28 B. This range of angles allows for rapid separation and re-convergence while minimizing back flow. In addition, each divergent branching portion and converging portion  38 A and  38 B,  42 A and  42 B,  46 A and  46 B,  50 A and  50 B,  54 A and  54 B and  58 A and  58 B extends from the centerline of the linear inlet flow channel  28 A,  28 B for a distance of one to three times the diameter of the channel  28 A,  28 B before reaching its respective wall  40 A and  40 B,  48 A and  48 B and  56 A and  56 B. Further note is made of the common areas  44 A and  44 B and  52 A and  52 B. These areas are directly centered about a same linear centerline which extends from the inlet flow channel portion  28 A,  28 B to the commencement of the connecting flow channel portion  32 A,  32 B. As a result, the common areas  44 A and  44 B and  52 A and  52 B are aligned linearly with the channel portions  28 A,  28 B and  32 A,  32 B, providing for more consistent, uniform flow. While several divergent, convergent, and common portions are illustrated, it is anticipated that as few as one divergent and convergent portion or as many as ten to twenty divergent and convergent portions may be used, depending upon the application and materials involved. 
       FIG. 6  depicts the turbulence-promoting after-mixer channels  30 A,  30 B from a side view when the molding assembly  20  is closed. As described above, upon closure, the upper half  22 A and the lower half  22 B meet, thereby creating the turbulence-promoting after-mixer along the region of the channel portions  30 A and  30 B. The resulting flow pathway causes the constituent materials flowing therethrough to deviate from a straight, generally linear path to a nonlinear turbulence-promoting path. The interaction and alignment of the divergent branching intersections  38 A and  38 B,  46 A and  46 B,  54 A and  54 B (referencing back to  FIG. 5 ), the convergent portions  42 A and  42 B,  50 A and  50 B,  58 A and  58 B, and the common portions  44 A and  44 B, and  52 A and  52 B, also as described above, is shown in detail. 
     In a particularly preferred embodiment, the after-mixer includes a plurality of bends or arcuate portions that cause liquid flowing through the fan gate to not only be directed in the same plane in which the flow channel lies, but also in a second plane that is perpendicular to the first plane. It is most preferable to utilize an after-mixer with bends such that liquid flowing therethrough travels in a plane that is perpendicular to both the previously noted first and second planes. This configuration results in relatively thorough and efficient mixing due to the rapid and changing course of direction of liquid flowing therethrough. 
     The configuration of the mold channels may take various forms. One such variation is shown in  FIG. 7 . Reference is made to the lower mold half  22 B for the purpose of illustration, and it is to be understood that the upper mold half  22 A (not shown) comprises a complimentary configuration. The adapter portion  26 B leads to the inlet flow channel  28 B which leads to the turbulence-promoting channel portion  30 B. However, instead of the adapter  26 B and the channels  28 B and  30 B being spaced apart from the central cavity  24 B, they are positioned approximately in line with the central cavity  24 B, eliminating the need for the connecting channel portion  32 B to be of a long, curved configuration to reach the fan gate portion  34 B. Thus, the connecting channel  32 B is a short, straight channel, promoting a material flow path which may be more desirable for some applications. The flow channels and the central cavity may be arranged according to other forms similar to those shown, which may occur to one skilled in the art, as equipment configurations and particular materials and applications dictate.  FIG. 7  also illustrates one or more nonretractable protrusions  36  in the molding chamber. 
     In the above-referenced figures, the channels  30 A and  30 B are depicted as each comprising a plurality of angled bends or turns. Turning now to  FIG. 8 , the channels are not limited to the angled bend-type fan gate configuration and include any turbulence-promoting design located in a region  59 B between the adapter portion  26 B and the cavity  24 B. Again, reference is made to the lower mold half  22 B for the purpose of illustration, and it is to be understood that the upper mold half  22 A (not shown) is complimentary to the lower mold half  22 B. The channels in the turbulence-promoting region  59 A (not shown) and  59 B could be formed to provide one or more arcuate regions such that upon closure of the upper and lower mold halves  22 A and  22 B, the flow gate has, for example, a spiral or helix configuration. Regardless of the specific configuration of the channels in the turbulence promoting portion  59 A and  59 B, the shape of the resulting flow gate insures that the materials flow through the turbulence-promoting region and thoroughly mix with each other, thereby reducing typical straight laminar flow and minimizing any settling in a low-flow area where degradation of flow may occur. Preferably, the shape and configuration of the flow channel is such that the velocity of the materials flowing therethrough is generally constant at different locations along the channel. And, as previously noted, such flow characteristics and thorough mixing of the materials has been found to lead to greater consistency and uniformity in the final physical properties and characteristics of the resulting golf ball layer or component.  FIG. 8  further illustrates one or more protrusions  36  in the molding chamber. 
     As shown in  FIG. 9 , the turbulence-promoting region  59 A (not shown) and  59 B may be placed in various locations in the upper and lower mold halves  22 A (not shown) and  22 B. As mentioned above, the turbulence-promoting region  59 B and the other flow channel portions  28 B,  32 B, and  34 B may be arranged so as to create an approximately straight layout between the adapter portion  26 B and the central cavity  24 B. By allowing flexibility in the location of the turbulence-promoting region  59 B and the other channel portions  28 B,  32 B and  34 B, as well as the adapter  26 B and the central cavity  24 B, optimum use may be made of the present invention in different applications.  FIG. 9  also illustrates one or more protrusions  36  in the molding chamber. 
     Gases, including air and moisture, are often present in a RIM process and create undesirable voids in the molded cover  14 . Venting of central cavity  24 A,  24 B reduces voids by removing these gases. Through the use of venting, a cover  14  is provided that is significantly more free from voids or other imperfections than a cover produced by a non-vented RIM process. 
     A preferred method of making a golf ball in accordance with the present invention is illustrated in  FIG. 10 . A golf ball core  12  made by techniques known in the art is obtained, illustrated as step  70 . The core  12  is preferably positioned within a mold having venting provisions, after-mixers, and fan gates as described herein. This is illustrated as step  72 . It is preferred that the core  12  is supported on a plurality of the previously described protrusions  36  that form deep dimples in the final ball. This is shown as step  74 . The mold is then closed. This is illustrated as step  75 . The cover layer  14  is molded over the core  12  by RIM as step  76 . If venting of gases from the molding cavity is desired, such gases are preferably vented as previously described. This is designated as step  78 . Should increased removal of gases be desired, the venting of step  78  is enhanced by providing a vacuum connection as known in the art to the venting channel. When the molding is complete, the golf ball  10  is removed from the mold, as shown by steps  79  and  80 . 
     In accordance with conventional molding techniques, the preferred embodiment molding processes described herein may utilize one or more mold release agents to facilitate removal of the molded layer or component from the mold. 
     A golf ball manufactured according the preferred method described herein exhibits unique characteristics. Golf ball covers made through compression molding and traditional injection molding include balata, ionomer resins, polyesters resins and polyurethanes. The selection of polyurethanes which can be processed by these methods is limited. Polyurethanes are often a desirable material for golf ball covers because balls made with these covers are potentially more resistant to scuffing and resistant to deformation than balls made with covers of other materials. The current invention allows processing of a wide array of grades of polyurethane through RIM which was not previously possible or commercially practical utilizing either compression molding or traditional injection molding. It is anticipated that other urethane resins such as Bayer® MP-7500, Bayer® MP-5000, Bayer® aliphatic or light stable resins, and Uniroyal® aliphatic and aromatic resins may be used. For example, utilizing the present invention method and Bayer® MP-10000 polyurethane resin, a golf ball with the properties described below has been provided. Also, depending upon the application, BASF aromatic or aliphatic resins may be used. 
     Some of the unique characteristics exhibited by a golf ball according to the present invention include a thinner cover without the accompanying disadvantages otherwise associated with relatively thin covers such as weakened regions at which inconsistent compositional differences exist. A traditional golf ball cover typically has a total thickness in the range of about 0.060 inches to 0.080 inches. A golf ball of the present invention may utilize a cover having a thickness of from about 0.002 inches to about 0.100 inches, more preferably from about 0.005 inches to about 0.075 inches, more preferably from about 0.010 inches to about 0.050 inches, and most preferably from about 0.015 inches to about 0.050 inches. This reduced cover thickness is often a desirable characteristic. It is contemplated that thinner layer thicknesses are possible using the present invention. 
     Because of the reduced pressure involved in RIM as compared to traditional injection molding, an outer cover or any other layer of the present invention golf ball is more dependably concentric and uniform with the core of the ball, thereby improving ball performance. That is, a more uniform and reproducible geometry is attainable by employing the present invention. 
     The present invention also provides a golf ball in which at least one cover or core layer is a fast-chemical-reaction-produced component. This component comprises at least one material selected from the group consisting of polyurethane, polyurea, polyurethane ionomer, epoxy, and unsaturated polyesters, and preferably comprises polyurethane. The invention also includes a method of producing a golf ball which contains a fast-chemical-reaction-produced component. A golf ball formed according to the invention preferably has a flex modulus in the range of from about 5 to about 310 kpsi, a Shore D hardness in the range of from about 20 to about 90, and good durability. Particularly preferred forms of the invention also provide for a golf ball with a fast-chemical-reaction-produced cover having good scuff resistance and cut resistance. As used herein, “polyurethane and/or polyurea” is expressed as “polyurethane/polyurea”. 
     A particularly preferred form of the invention is a golf ball with a cover comprising polyurethane, the cover including from about 5 to about 100 weight percent of polyurethane formed from recycled polyurethane. 
     The method of the invention is particularly useful in forming golf balls because it can be practiced at relatively low temperatures and pressures. The preferred temperature range for the method of the invention is from about 50 EF to about 250EF and preferably from about 120 EF to about 180 EF when the component being produced contains polyurethane. Preferred pressures for practicing the invention using polyurethane-containing materials are 200 psi or less and more preferably 100 psi or less. The method of the present invention offers numerous advantages over conventional slow-reactive process compression molding of golf ball covers. The method of the present invention results in molded covers in a demold time of 10 minutes or less. An excellent finish can be produced on the ball. 
     The method of the invention also is particularly effective when recycled polyurethane or other polymer resin, or materials derived by recycling polyurethane or other polymer resin, is incorporated into the product. 
     As indicated above, the fast-chemical-reaction-produced component can be one or more cover and/or core layers of the ball. When a polyurethane cover is formed according to the invention, and is then covered with a polyurethane top coat, excellent adhesion can be obtained. The adhesion in this case is better than adhesion of a polyurethane coating to an ionomeric cover. This improved adhesion can result in the use of a thinner top coat, the elimination of a primer coat, and the use of a greater variety of golf ball printing inks beneath the top coat. These include but are not limited to typical inks such as one component polyurethane inks and two component polyurethane inks. 
     More specifically, the preferred method of forming a fast-chemical-reaction-produced component for a golf ball according to the invention is by RIM. In this approach, highly reactive liquids are injected into a closed mold, mixed usually by impingement and/or mechanical mixing and secondarily mixed in an in-line device such as a peanut mixer, where they polymerize primarily in the mold to form a coherent, one-piece molded article. The RIM processes usually involve a rapid reaction between one or more reactive components such as polyether—or polyester—polyol, polyamine, or other material with an active hydrogen, and one or more isocyanate—containing constituents, often in the presence of a catalyst. The constituents are stored in separate tanks prior to molding and may be first mixed in a mix head upstream of a mold and then injected into the mold. The liquid streams are metered in the desired weight to weight ratio and fed into an impingement mix head, with mixing occurring under high pressure, e.g., 1500 to 3000 psi. The liquid streams impinge upon each other in the mixing chamber of the mix head and the mixture is injected into the mold. One of the liquid streams typically contains a catalyst for the reaction. The constituents react rapidly after mixing to gel and form polyurethane polymers. Polyureas, epoxies, and various unsaturated polyesters also can be molded by RIM. 
     As previously noted, RIM differs from non-reaction injection molding in a number of ways. The main distinction is that in RIM a chemical reaction takes place in the mold to transform a monomer or adducts to polymers and the components are in liquid form. Thus, a RIM mold need not be made to withstand the pressures which occur in a conventional injection molding. In contrast, injection molding is conducted at high molding pressures in the mold cavity by melting a solid resin and conveying it into a mold, with the molten resin often being at about 150 to about 350 EC. At this elevated temperature, the viscosity of the molten resin usually is in the range of 50,000 to about 1,000,000 centipoise, and is typically around 200,000 centipoise. In an injection molding process, the solidification of the resins occurs after about 10 to 90 seconds, depending upon the size of the molded product, the temperature and heat transfer conditions, and the hardness of the injection molded material. Subsequently, the molded product is removed from the mold. There is no significant chemical reaction taking place in an injection molding process when the thermoplastic resin is introduced into the mold. In contrast, in a RIM process, the chemical reaction typically takes place in less than about 2 minutes, preferably in under one minute, and in many cases in about 30 seconds or less. 
     If plastic products are produced by combining components that are preformed to some extent, subsequent failure can occur at a location on the cover which is along the seam or parting line of the mold. Failure can occur at this location because this interfacial region is intrinsically different from the remainder of the cover layer and can be weaker or more stressed. The present invention is believed to provide for improved durability of a golf ball cover layer by providing a uniform or seamless cover in which the properties of the cover material in the region along the parting line are generally the same as the properties of the cover material at other locations on the cover, including at the poles. The improvement in durability is believed to be a result of the fact that the reaction mixture is distributed uniformly into a closed mold. This uniform distribution of the injected materials reduces or eliminates knit-lines and other molding deficiencies which can be caused by temperature difference and/or reaction difference in the injected materials. The process of the invention results in generally uniform molecular structure, density and stress distribution as compared to conventional injection-molding processes. 
     The fast-chemical-reaction-produced component has a flex modulus of from about 1 to about 310 kpsi, more preferably from about 1 to about 100 kpsi, and most preferably from about 2 to about 50 kpsi. The subject component can be a cover with a flex modulus which is higher than that of the centermost component of the cores, as in a liquid center core and some solid center cores. Furthermore, the fast-chemical-reaction-produced component can be a cover with a flex modulus that is higher than that of the immediately underlying layer, as in the case of a wound core. The core can be one piece or multi-layer, each layer can be either foamed or unfoamed, and density adjusting fillers, including metals, can be used. The cover of the ball can be harder or softer than any particular core layer. 
     The fast-chemical-reaction-produced component can incorporate suitable additives and/or fillers. When the component is an outer cover layer, pigments or dyes, accelerators and UV stabilizers can be added. Examples of suitable optical brighteners which probably can be used include Uvitex® and Eastobrite® OB-1. An example of a suitable white pigment is titanium dioxide. Examples of suitable and UV light stabilizers are provided in commonly assigned U.S. Pat. No. 5,494,291. Fillers which can be incorporated into the fast-chemical-reaction-produced cover or core component include those listed below in the definitions section. Furthermore, compatible polymeric materials can be added. For example, when the component comprises polyurethane and/or polyurea, such polymeric materials include polyurethane ionomers, polyamides, etc. 
     A golf ball core layer formed from a fast-chemical-reaction-produced material according to the present invention typically contains 0 to 20 weight percent of such filler material, and more preferably 1 to 15 weight percent. When the fast-chemical-reaction-produced component is a core, the additives typically are selected to control the density, hardness and/or COR. 
     A golf ball inner cover layer formed from a fast-chemical-reaction-produced material according to the present invention typically contains 0 to 60 weight percent of filler material, more preferably 1 to 30 weight percent, and most preferably 1 to 20 weight percent. 
     A golf ball outer cover layer formed from a fast-chemical-reaction-produced material according to the present invention typically contains 0 to 20 weight percent of filler material, more preferably 1 to 10 weight percent, and most preferably 1 to 5 weight percent. 
     Catalysts can be added to the RIM polyurethane system starting materials as long as the catalysts generally do not react with the constituent with which they are combined. Suitable catalysts include those which are known to be useful with polyurethanes and polyureas. 
     The reaction mixture viscosity should be sufficiently low to ensure that the empty space in the mold is completely filled. The reactant materials generally are preheated to about 80 EF to about 200 EF and preferably to 100 EF to about 180 EF before they are mixed. In most cases it is necessary to preheat the mold to, e.g., from about 80 EF to about 200 EF, to provide for proper injection viscosity. 
     As indicated above, one or more cover layers of a golf ball can be formed from a fast-chemical-reaction-produced material according to the present invention. 
     Referring to  FIG. 11 , another preferred embodiment golf ball having a cover comprising a RIM polyurethane is shown. The golf ball  110  includes a polybutadiene core  112  and a polyurethane cover  114  formed by RIM. The golf ball  110  defines a plurality of dimples  116  along its outer surface. Preferably, the ball  110  also defines one or more deep dimples  118  as described in greater detail herein. 
     Referring now to  FIG. 12 , the golf ball  110  having a core comprising a RIM polyurethane is shown. The golf ball  110  has a RIM polyurethane core  112 , and a RIM polyurethane cover  114 . The golf ball  110  defines a plurality of dimples  116  along its outer surface. Preferably, the ball  110  also defines one or more deep dimples  118  as described in greater detail herein. 
     Referring to  FIGS. 13 and 14 , a multi-layer golf ball  210  is shown with a solid core  212  containing recycled RIM polyurethane, a mantle cover layer comprising RIM polyurethane  213 , and an outer cover layer  214  comprising ionomer or another conventional golf ball cover material. Non-limiting examples of multi-layer golf balls according to the invention with two cover layers include those with RIM polyurethane mantles having a thickness of 0.01 to 0.20 inches, or thinner, and a Shore D hardness of 20 to 80, covered with ionomeric or non-ionomeric thermoplastic, balata or other covers having a Shore D hardness of 20 to 80 and a thickness of 0.010 to 0.20 inches. The golf ball  210  defines a plurality of dimples  216  along its outer surface. Preferably, the ball  210  also defines one or more deep dimples  218  as described in greater detail herein. 
     Referring again to  FIGS. 11 and 12 , those figures illustrate a preferred embodiment golf ball  110  produced in accordance with the present invention. One or more of the deep dimples  120 , and preferably two or more of the dimples  120 , and more preferably three or more of the dimples per hemisphere, extend into the core  112  disposed underneath the cover layer  114 . These dimples are herein referred to as deep dimples. 
     The preferred embodiment golf ball  210  shown in  FIGS. 13 and 14  comprises a core  212  having an inner cover layer  213  disposed thereon and an outer cover layer  214  formed about the inner cover layer  213 . The cover layers  213  and  214  define a plurality of dimples  216  along the outer surface of the outer cover layer  160 . One or more of the dimples, and preferably two or more of the dimples, and more preferably three or more of the dimples per hemisphere, extend entirely through the outer cover layer  214  and at least partially into or to the inner cover layer  213 . These dimples, which extend through the outer cover layer, are again referred to herein as deep dimples and shown in  FIG. 13  as dimples  218 . 
     The deep dimples can be circular, non-circular, a combination of circular and non-circular, or any other shape desired. They may be of the same or differing shape, such as a circular larger dimple having an oval smaller dimple within the circular dimple, or an oval larger dimple having a circular or other shape within the larger dimple. The dimples do not have to be symmetrical. 
     Providing deep dimples formed in multiple layers allows the dimple depth to be spread over two or more layers.  FIG. 13  illustrates deep dimple  220  formed in both the inner cover layer and the outer cover layer. The inner portion of the dimple  220  is formed in the inner cover layer  213 , and the outer portion of the dimple  220  is formed in the outer cover layer  214 . For a two-piece ball, dimples may be formed in the core and the single cover layer in the same way as previously described. Additionally, dimples may be formed in more than two cover and/or core layers if desired. 
     In another preferred embodiment, a multi-layer golf ball is produced that has one or more deep dimples that protrude into the ball through at least one layer, such as an outer cover layer. In a further preferred embodiment, the deep dimple protrudes through at least two layers. The dimples of the at least two layers are configured with the same geometric coordinates (that is, the approximate center of the both dimples would be in the same location, and so the dimples are concentric with respect to each other), producing a golf ball having a dimpled layer over a dimpled layer. This allows for much thinner layers with traditional dimples. The dimples of one or more inner layers may be of varying depths, diameters and radii, yet still aligned with the dimples of the outer layer. This also allows for a dimple within a dimple, where there is a smaller dimple in at least one inner or mantle layer that is within a larger diameter dimple in the outer layer, such as the dimples shown in  FIGS. 15 to 18 . 
       FIGS. 15 to 18  illustrate a deep dimple that is a dual radius dimple, or a dimple within a dimple. One advantage of a dual radius dimple is that the deeper part of the dual radius may be filled in with a coating or other material. This provides an effective method for forming dimple depths to a desired value as compared to other methods of dimple formation. The dimple shape may be any shape desired, and each dimple may be the same or different shape. Preferably, the depth of the second or deepest portion of the dual radius dimple may be expressed as a percentage of the total depth of the dimple. Specifically, the region or portion of the dimple which extends to the outermost surface of the ball may be referred to herein as the “major” dimple. And, likewise, the portion of the dimple which extends to the deepest portion or depth of the dimple can be referred to herein as the “minor” dimple. Accordingly, the preferred depth of the major dimple is approximately from about 40% to about 80% of the overall dimple depth. Accordingly, the preferred depth of the minor dimple is approximately 20% to about 60% of the overall dimple depth. The depth being measured from the chord of the major dimple to the bottom of the minor dimple. With regard to diameters, the preferred diameter of the minor dimple is from about 10% to about 70% of the diameter of the major dimple. 
       FIG. 15  is a cross-sectional detail illustrating a portion of a preferred embodiment golf ball produced in accordance with the present invention. This preferred embodiment golf ball  310  comprises a core  320  having a cover layer  330  formed thereon. The cover layer defines at least one deep dimple  340  along its outer surface  335 . As previously described, it is preferred that one or more (preferably two or more, more preferably three or more per hemisphere) of the dimples extends entirely through the cover layer and into the core disposed underneath the cover layer.  FIG. 15  illustrates a deep dimple defined by two different curvatures. Referring to  FIG. 15 , a first radius R 1  defines the portion of the dimple from the outer surface  335  of the golf ball  310  to a point at which the deep dimple extends into a layer underneath the cover layer. At this point, the curvature of the dimple changes and is defined by radius R 2 . Preferably, R 1 , is from about 0.130 inches to about 0.190 inches, and most preferably, R 1 , is from about 0.140 to about 0.180 inches. For some embodiments, R 1  ranges from about 0.100 inches to about 1.000 inch, and most preferably from about 0.200 inches to about 0.800 inches. Preferably, R 2  is from about 0.025 inches to about 0.075 inches, and most preferably, R 2  is about 0.050 to about 0.065 inches. For some embodiments, R 2  ranges from about 0.002 inches to about 0.500 inches, and most preferably from about 0.010 inches to about 0.200 inches. The overall diameter or span of the dimple  340  is designated herein as D 1 . The diameter or span of the portion of the dimple that extends into the layer underneath the outer cover layer is designated herein as D 2 . Preferably, D 1  is from about 0.030 inches to about 0.250 inches, more preferably from about 0.100 inches to about 0.186 inches, and most preferably, D 1  is about 0.146 inches to about 0.168 inches. For some embodiments, D 1  ranges from about 0.100 inches to about 0.250 inches, and most preferably D 1  is about 0.140 inches to about 0.180 inches. Preferably D 2  is from about 0.020 inches to about 0.160 inches, more preferably from about 0.030 inches to about 0.080 inches, and most preferably, D 2  is about 0.056 inches. For some embodiments, D 2  is from about 0.040 inches to about 0.060 inches. Accordingly, the overall depth of the deep dimple portion that is defined by R 1  is designated herein as H 1  and the depth or portion of the dimple that is defined by R 2  is designated herein as H 2 . Preferably, H 1  is from about 0.005 inches to about 0.135 inches, more preferably from about 0.005 to about 0.025 inches, more preferably from about 0.010 inches to about 0.015 inches, and most preferably, H 1  is about 0.015 inches. For some embodiments, H 1  is from about 0.005 inches to about 0.015 inches. H 2  may range from about 0.005 inches to about 0.135 inches, and more preferably from about 0.005 to about 0.050 inches. Preferably, H 2  ranges from about 0.005 inches to about 0.030 inches and is about 0.010 inches. For some embodiments, H 2  is from about 0.005 inches to about 0.015 inches. 
     Referring to  FIG. 16 , another preferred embodiment golf ball  410  is illustrated. In this version of the present invention, a golf ball  410  comprises a core  420  and a cover layer  430  formed thereon. The cover layer  430  defines at one deep dimple  440  along the outer surface  435  of the golf ball  410 . As can be seen, the dimple  440  is defined by two different curvatures, each of which is defined by radii R 2  and R 1  as previously described with respect to  FIG. 15 . The other parameters D 1 , D 2 , H 1 , and H 2  are as described with respect to  FIG. 15 .  FIG. 16  illustrates an embodiment in which the dimple  440  extends to the core  420  and not significantly into the core. In contrast, the version illustrated in  FIG. 15  is directed to a dimple configuration in which a dimple extends significantly into the underlying core. 
       FIG. 17  illustrates a preferred embodiment golf ball  510  comprising a core  520 , a mantle or inner cover layer  550 , and an outer cover layer  560 . The outer cover layer  560  and inner cover layer  550  define at least one deep dimple  540  along the outer surface  535  of the ball  510 . The dimple  540  is defined by two different regions or two curvatures, each of which is in turn defined by radii R 2  and R 1 . The other parameters D 1 , D 2 , H 1 , and H 2  are as described with respect to  FIG. 15 . As can be seen in  FIG. 17 , the dimple  540  extends entirely through the outer cover layer  560  and into the inner cover layer or mantle layer  550 . 
       FIG. 18  illustrates another preferred embodiment golf ball  610  in accordance with the present invention. The golf ball  610  comprises a core  620  having disposed thereon an inner cover layer or mantle layer  650  and an outer cover layer  660 . Defined along the perimeter or outer periphery of the ball  610  is at least one deep dimple  640 . The dimple  640  is defined along the outer surface  635  of the ball  610 . The dimple  640  has two different regions or curvatures each defined by radii R 2  and R 1 . The other parameters D 1 , D 2 , H 1 , and H 2  are as described with respect to  FIG. 15 . The version illustrated in  FIG. 18  reveals a dimple  640  that does not significantly extend into the mantle layer or inner cover layer  650 . Instead, the dimple  640  only extends to the outermost region of the mantle layer or inner cover layer  650 . 
     An important characteristic of dimple configuration is the volume ratio. The volume ratio is the sum of the volume of all dimples taken below a chord extending across the top of a dimple, divided by the total volume of the ball. The volume ratio is a critical parameter for ball flight. A high volume ratio generally results in a low flying ball. And a low volume ratio often results in a high-flying ball. A preferred volume ratio is about 1%. The balls of the present invention however may be configured with greater or lesser volume ratios. 
     The number and/or layout of dimples will not necessarily change the coverage, i.e. surface area. A typical coverage for a ball of the present invention is about 60% to about 90% and preferably about 83.8%. In other embodiments, this preferred coverage is about 84% to about 85%. These percentages are the percent of surface area of the ball occupied by dimples. It will be appreciated that the present invention golf balls may exhibit coverages greater or less than that amount. 
     For configurations utilizing dimples having two or more regions of different curvature, i.e. dimple within a dimple, there is less impact on the volume ratio than the use of deep dimples. If there are enough of either dimples within dimples or deep dimples, the aerodynamics of the ball will eventually be impacted. 
     The optimum or preferred number of deep dimples utilized per ball varies. It is the amount necessary to secure or center the core or core and cover layer(s) during molding without adversely affecting the aerodynamics of the finished ball. However, the present invention includes the use of a relatively large number of deep dimples. That is, although most of the focus of the present invention is directed to the use of only a few deep dimples per golf ball, i.e. from 2 to 6, the invention includes the use of a significantly greater number such as from about 50 to about 250. It is also contemplated that for some applications, it may be desirable to form all, or nearly all, dimples on a golf ball as deep dimples such as, for example, from about 50 to about 500. 
     In certain golf ball embodiments, it may be desirable to form a particular proportion of the dimples along the outer surface of the golf ball as deep dimples. The proportion selected may depend upon aesthetics, aerodynamic effects, marketability factors, ball performance, manufacturing, or other factors. Generally, the proportion of dimples that may be formed as deep dimples may be all, substantially all, a majority, half, a minority, or a minor number. 
     More specifically, in certain embodiments, it is desirable to form a specific proportion of all dimples along the outer surface of a golf ball as deep dimples. For instance, it may be desirable to form all dimples, i.e. 100%, as deep dimples. In other embodiments, it may be desirable to form at least 95% of all dimples as deep dimples. Or, it may be desirable to form at least 90% of all dimples as deep dimples. Alternatively, it may be desirable to form at least 85%, at least 80%, at least 75%, at least 70%, at least 65%, at least 60%, at least 55%, at least 50%, at least 45%, at least 40%, at least 35%, at least 30%, at least 25%, at least 20%, at least 15%, at least 10%, at least 5%, or at least 1% as deep dimples. 
     In forming golf balls with a particular number of deep dimples, it will be appreciated that the molding equipment employed to form such balls utilizes a molding chamber having a molding surface with a corresponding number of outwardly extending protuberances or projections as described herein. 
     Furthermore, the processes and equipment described herein for reaction injecting molding a polyurethane or polyurethane derivative material, are well suited for forming a golf ball with a relatively large proportion of deep dimples. Although not wishing to be bound to any particular theory or limiting reason, it is believed that the mixing and molding characteristics of the molding material and that associated with the process and equipment, enable and promote the formation of one or more cover layers that define a large number of well defined deep dimples. 
     One particularly preferred embodiment golf ball includes multiple populations of dimples along its outer surface. For example, two, three, four, five, six or more different types or populations of dimples may be provided. One or more of the multiple populations are preferably deep dimples. The other populations may include a wide array of dimple types such as, but not limited to, conventional dimples, non-conventional dimples, or dimples known in the prior art. 
     In general, as dimples are made deeper, the ball will fly lower as compared to the use of dimples that are shallower. As the number of deep dimples increases, the ball will exhibit a lower flight trajectory. Accordingly, the preferred approach is to utilize a smaller number of deep dimples. However, for other applications, the present invention includes a ball with many deep dimples. 
     The overall shape of the dimples, including deep dimples, may be nearly any shape. For example, shapes such as hexagon, pentagon, triangle, ellipse, circle, etc. are all suitable. There is no limit to the number of shapes, although some shapes are preferred over others. At present, circular dimples are preferred. As for the cross-sectional configuration, the dimples may utilize any geometry. For instance, dimples may be defined by a constant curve or a multiple curvature or dual radius configuration or an elliptical or teardrop shaped region. 
       FIG. 19  illustrates a preferred embodiment molding apparatus  1000  in accordance with the present invention. Molding apparatus  1000  comprises two mold halves  1020  and  1040  that each define a hemispherical portion of a molding chamber  1024  and  1044 . Defined along the outer surface of the hemispherical portion of the molding chamber  1024  are a plurality of raised protrusions or support pins  1032 . These raised regions or support pins form dimples in a cover layer in a golf ball formed using molding apparatus  1000 . Also provided along the outer surface of the hemispherical molding chamber  1024  are a plurality of outwardly extending or raised regions or support pins  1026 ,  1028 , and  1030 . These raised regions are of a height greater than the height of the raised regions  1032 . Specifically, the raised regions  1026 ,  1028 , and  1030  form deep dimples as described herein. These raised regions are used to retain and support a golf ball core placed in the mold. These raised regions also serve to form deep dimples  1018  in the golf ball  1010 . A passage  1022  is provided in the mold half  1020  as will be appreciated. The passage  1022  provides communication and a path for a flowable moldable material to be introduced into the molding chamber. The molding apparatus  1000  also includes a second molding portion or plate  1040 . The plate  1040  defines a hemispherical molding chamber  1044  also having a plurality of raised regions or support pins along its outer surface. Specifically, raised regions  1046  and  1048  are provided similar to the previously described raised regions  1026 ,  1028 , and  1030 . The molding plate  1040  also defines a channel  1042  extending from the molding chamber  1044  to the exterior of the plate. Most preferably, the molding channel  1042  is aligned with channel  1022  in the other plate  1020  when the mold is closed to provide a unitary passage providing communication between the molding chamber and the exterior of the mold. It will be appreciated that this figure is not necessarily to scale, and so channel  1042  would likely be significantly smaller in a commercial manufacturing application. Preferably, a turbulence-inducing after-mixer is provided in the mold halves as previously described in conjunction with  FIGS. 2-9 . Similarly, provisions for a dump well and associated venting are also provided as previously described. A golf ball core placed in the molding chamber  1024 ,  1044  is supported by the various raised regions  1026 ,  1028 ,  1030 ,  1046 , and  1048  as previously described. Upon molding a suitable cover layer on the core or intermediate ball assembly, the golf ball  1010  is produced. 
     Certain preferred embodiment molding equipment in accordance with the present invention utilize molds with molding surfaces that provide a collection of different types or heights of raised regions or outwardly extending projections. Specifically, it may in some instances be desirable to provide a molding surface with a first population of raised regions that define a first type of dimple and another population of raised regions that define deep dimples as described herein. The second or other population of raised regions that form deep dimples may constitute a minority proportion or a majority proportion of all the dimples defined on the resulting golf ball. It is also contemplated to provide a number of different shapes, sizes, heights, and configurations or raised regions along a molding surface. As will be appreciated, this is an efficient manner to form a golf ball with a relatively large number of deep dimples. 
     Additionally, golf balls of the present invention that comprise polyurethane/polyurea (or other suitable materials) in any of the inner and outer cover layer may be produced by RIM, as previously described. 
     Golf balls and, more specifically, cover layers formed by RIM are preferably formed by the process described in application Ser. No. 09/040,798, filed Mar. 18, 1998, incorporated herein by reference, or by a similar RIM process. 
     The golf balls, and particularly the cover layer(s), of the present invention may also be formed by liquid injection molding (LIM) techniques, or any other method known in the art. 
     The golf balls formed according to the present invention can be coated using a conventional two-component spray coating or can be coated during the RIM process, for example, using an in-mold coating process. 
     Referring next to  FIG. 20 , a process flow diagram for forming a RIM cover of polyurethane is shown. Isocyanate from bulk storage is fed through line  1180  to an isocyanate (or polyisocyanate) tank  1200 . The isocyanate is heated to the desired temperature, e.g., 808 F to about 2208 F, by circulating it through heat exchanger  1182  via lines  1184  and  1186 . Polyol, polyamine, or another compound with an active hydrogen atom is conveyed from bulk storage to a polyol tank  1208  via line  1188 . The polyol is heated to the desired temperature, e.g., 908 F to about 1808 F, by circulating it through heat exchanger  1190  via lines  1192  and  1194 . Generally, it is preferred to heat each reactive component such as the isocyanate and the polyol, to a temperature such that they have the same viscosity. Preferably, these temperatures are about 808 F to about 2208 F for the polyol component and about 808 F to about 2208 F for the isocyanate component. More preferably, the polyol is at a temperature of about 1008 F and the isocyanate is at about 2008 F. Dry nitrogen gas is fed from nitrogen tank  1196  to isocyanate tank  1200  via line  1197  and to polyol tank  1208  via line  1198 . This gaseous blanket is used to prevent oxidation or other deleterious reaction of the injection components. Isocyanate is fed from isocyanate tank  1200  via line  1202  through a metering cylinder or metering pump  1204  into recirculation mix head inlet line  1206 . An isocyanate recirculation line  1250  is preferably utilized. Polyol is fed from polyol tank  1208  via line  1210  through a metering cylinder or metering pump  1212  into a recirculation mix head inlet line  1214 . A polyol recirculation line  1260  is preferably utilized. A recirculation mix head  1216  receives isocyanate and polyol, mixes them, and provides for them to be fed through nozzle  1218  into injection mold  1220 . The injection mold  1220  has a top mold  1222  and a bottom mold  1224 . Heat exchange fluid flows through cooling lines  1226  in the top mold  1222  and lines  1240  in the bottom mold  1224 . The materials are kept under controlled temperature conditions so that the desired reaction profile is maintained. Preferably, controlled temperatures are maintained by using oil heaters or other heating medium along the entirety of each of the paths or lines for the reactants. Preferably, temperature control of the isocyanate lines  1202  and  1250  is achieved by use of a heat exchanger  1300  and heat exchange line  1302  as shown in  FIG. 22 . Similarly, temperature control of the polyol lines  1210  and  1260  is achieved by use of a heat exchanger  1310  and heat exchange line  1312  as shown in  FIG. 23 . Most preferably, a multiple pipe assembly is used for heat exchange in which the isocyanate or polyol materials flows within a central tube or conduit and a heat exchange fluid flows in another portion of the assembly, preferably disposed radially around the conduit housing the isocyanate or polyol material. An effective amount of thermal insulation is preferably disposed around the exterior or outer periphery of the multiple pipe assembly. 
     The polyol component typically contains additives, such as stabilizers, flow modifiers, catalysts, combustion modifiers, blowing agents, fillers, pigments, optical brighteners, and release agents to modify physical characteristics of the cover 
     Inside the mix head  1216 , injector nozzles impinge the isocyanate and polyol at ultra-high velocity to provide excellent mixing. Additional mixing preferably is conducted using an after-mixer  1230 , which typically is constructed inside the mold between the mix head and the mold cavity. 
     As is shown in  FIG. 21 , the mold  1220  includes a golf ball cavity chamber  1232  in which a spherical golf ball mold  1234  with a dimpled, spherical mold cavity  1236  defined. Preferably, an effective amount of a mold release agent is applied to the molding surfaces of the molding chamber. The aftermixer  1230  can be a peanut aftermixer, as in shown in  FIG. 5 , or in some cases another suitable type, such as a heart, harp or dipper. An overflow channel  1238  or “dump well” receives overflow material from the golf ball mold  1234  through a shallow vent  1242 . Heating/cooling passages  1226  and  1240 , which preferably are in a parallel flow arrangement, carry heat transfer fluids such as water, oil, etc. through the top mold  1222  and the bottom mold  1224 . Injection may be performed at various pressures, but it is preferred that the pressure at which each of the components is introduced to the molding assembly is approximately equal. Preferably, impingement pressures for a RIM process using an isocyanate and a polyol component are about 150 to about 195 bar, and preferably about 180 bar (all pressures are gauge, i.e. above atmospheric, unless noted otherwise). For the RIM processes described herein, mold cycle times may range from about 30 seconds to up to 5 minutes or more depending upon the properties of the reactants. For a RIM system using a polyol and an isocyanate as described herein, a 60 second molding cycle time has been achieved, and is preferred. 
     After molding, the golf balls produced may undergo various further processing steps such as buffing, trimming, milling, tumbling, painting and marking as disclosed in U.S. Pat. No. 4,911,451, herein incorporated by reference. 
     In performing a RIM operation in which polyurethane covers or other golf ball components are formed, it is preferred to use a PSM 90 unit available from Isotherm, AG. The PSM 90 unit is used for processing of elastomers and foamed polyurethane and polyureas. Generally, the polyol and isocyanate components are metered into the PSM 90 and at least partially mixed under high pressure. Depending upon the mixing head used, a wide array of different molding strategies can be used. Additionally, a design guide for after-mixers is provided by Bayer Corporation under the designation  Engineering Polymers, RIM Part and Mold Design, Polyurethanes, a Design Guide , No. PU-CA007, pp. 52-53 and 58, 1995, herein incorporated by reference. 
     The resulting golf ball is produced more efficiently and less expensively than balls of the prior art. Additionally, the golf balls of the present invention may have multiple cover layers, some of them very thin (less than 0.03 inches, more preferably less than 0.02 inches, even more preferably less than 0.01 inches) if desired, to produce golf balls having specific performance characteristics. For example, golf balls having softer outer cover layer(s) and harder inner cover layer(s) may be produced. Alternatively, golf balls having harder outer cover layer(s) and softer inner cover layer(s) may be produced. Moreover, golf balls having inner and out cover layers with similar hardnesses are also anticipated by the present invention. 
     For golf balls have three or more layers, the hardness of the layers may be varied alternately, such as hard-soft-hard, or soft-hard-soft, and the like, or golf balls with a cover having a hardness gradient may be produced. The hardness gradient may start with hard inner layers close to the core and get softer at the outer layer, or vice versa. This allows a lot of flexibility and control of finished golf ball properties. As previously described, the layers may be of the same or different materials, and of the same or different thicknesses. 
     Specifically, the golf ball of the present invention is not particularly limited with respect to its structure and construction. By using well known ball materials and conventional manufacturing processes, the balls may be manufactured as solid golf balls including one-piece golf balls, two-piece golf balls, and multi-piece golf balls with three or more layers and wound golf balls. Furthermore, although a RIM process has been described for forming the various gold balls, cores, intermediate ball assemblies, cover layers, and components thereof, it will be appreciated that other techniques may be used, such as, but not limited to, injection molding, compression molding, cast molding, and other processes known in the art. 
     The foregoing description is, at present, considered to be the preferred embodiments of the present invention. However, it is contemplated that various changes and modifications apparent to those skilled in the art, may be made without departing from the present invention. Therefore, the foregoing description is intended to cover all such changes and modifications encompassed within the spirit and scope of the present invention, including all equivalent aspects.