Abstract:
A system for dispensing liquid material onto a moving substrate includes a liquid dispenser fluidly connected to a source of liquid material and a source of pressurized air. The liquid dispenser includes a pair of outer liquid material outlets and a plurality of inner liquid material outlets therebetween spaced along a common axis at one end of the dispenser for dispensing a plurality of strands of liquid material toward the substrate. The liquid dispenser further includes a pair of air outlets associated with each of the inner liquid material outlets and a single air outlet associated with each of the outer liquid material outlets for emitting pressurized air that is operable to oscillate the dispensed strands in directions predominantly parallel with the common axis of the liquid material outlets during flight toward the substrate to form an overlapping pattern of liquid material on the moving substrate. Methods for dispensing liquid material onto a moving substrate are also disclosed.

Description:
CROSS-REFERENCE 
     The present application is a continuation-in-part of copending application Ser. No. PCT/US99/08519, filed on Apr. 16, 1999, which claims the filing benefit of U.S. Ser. No. 60/082,069, filed on Apr. 17, 1998, each disclosure of which is hereby incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to material dispensing systems for applying material onto a substrate and, more particularly, to a material dispensing system having a modular die assembly for applying in a controlled manner patterns of fibrous material onto a moving substrate. 
     BACKGROUND OF THE INVENTION 
     Various dispensing systems have been used in the past for applying patterns of viscous material onto a moving substrate. In the production of disposable diapers, incontinence pads and similar articles, for example, hot melt adhesive dispensing systems have been developed for applying a laminating or bonding layer of hot melt thermoplastic adhesive between a non-woven fibrous layer and a thin polyethylene backsheet. Typically, the hot melt adhesive dispensing system is mounted above a moving polyethylene backsheet layer and applies a uniform pattern of hot melt adhesive material across the upper surface width of the backsheet substrate. Downstream of the dispensing system, a non-woven layer is laminated to the polyethylene layer through a pressure nip and then further processed into a final usable product. 
     In one known hot melt adhesive dispensing system, continuous beads or strands of adhesive are emitted from a multiple adhesive outlet die with multiple air jets oriented around the circumference of each material outlet. The multiple air jets drive air tangentially relative to the orientation of the adhesive strand as it emits from the die orifice, thereby attenuating each adhesive strand and causing the strands to swirl before being deposited on the upper surface of the moving substrate. 
     More recently, manufacturers of diaper products and others have been interested in small fiber technology for the bonding layer of hot melt adhesive in non-woven and polyethylene sheet laminates. To this end, hot melt adhesive dispensing systems have incorporated slot nozzle dies with a pair of angled air channels formed on either side of the elongated extrusion slot of the die. As the hot melt adhesive emits from the extrusion slot as a continuous sheet or curtain, pressurized air is emitted as a pair of curtains from the air channels to impinge upon, attenuate and fiberize the adhesive curtain to form a uniform fibrous web of adhesive on the substrate. Recently, fibrous web adhesive dispensers have incorporated intermittent control of adhesive and air flows to form discrete patterns of fibrous adhesive layers with well defined cut-on and cut-off edges and well defined side edges. 
     Meltblown technology has also been adapted for use in this area to produce a hot melt adhesive bonding layer having fibers of relatively small diameter. Meltblow dies typically include a series of closely spaced adhesive nozzles that are aligned on a common axis across the die head. A pair of angled air channels are formed on either side of the adhesive nozzles to extend parallel to the common nozzle axis. As hot melt adhesive emits from the series of aligned nozzles, pressurized air is emitted from the air channels as a pair of curtains that impinge upon, draw down and attenuate the fibers before they are applied to the moving substrate. 
     While meltblown technology has been used to produce fibrous adhesive layers on moving substrates, it has several drawbacks. As those skilled in the art will appreciate, meltblown technology typically uses a high volume of high velocity air to draw down and attenuate the emitted adhesive strands. The high velocity air causes the fibers to oscillate in a plane that is generally aligned with the movement of the substrate, i.e., in the machine direction. To adequately blend adjacent patterns of adhesive to form a uniform layer on the substrate, meltblow dispensers require the nozzles to be closely spaced. Moreover, the volume and velocity of the air must be high enough to sufficiently agitate and blend adjacent fibers. 
     However, the high volume of air used in meltblown dispensers adds to the overall operational cost as well as reduces the ability to control the pattern of emitted fibers. One byproduct of the high velocity air is “fly” in which the fibers get blown away from the desired deposition pattern. The “fly” can be deposited either outside the desired edges of the pattern, or even build up on the dispensing equipment which can cause operational problems that require significant maintenance. Another byproduct of the high velocity air and closely spaced nozzles is “shot” in which adjacent adhesive fibers become entangled and form globules of adhesive on the backsheet substrate. “Shot” is undesirable as it can cause heat distortion of the delicate polyethylene backsheet. 
     It will further be appreciated by those skilled in the art that the construction of the meltblow dies, with the continuous sheets of air formed on either side and parallel to the aligned nozzles, reduces the ability of manufacturers to modularize the meltblow dies in side-by-side fashion across the width of a moving substrate. The curtains of air are interrupted between adjacent melt blow dies which generally results in a less consistent fiber pattern on the substrate. 
     Additionally, the many closely spaced nozzles required in meltblow dies not only adds to manufacturing costs, but also forces lower material flow rates through each nozzle. Lower material flow rates per nozzle generally results in a greater variation of the fibers emitted from the nozzles. Moreover, the nozzles are typically more likely to clog at the lower material flow rates. 
     Thus, there is a need for a material dispensing system that improves control of dispensed material to form patterns on a moving substrate without “fly” or “shot”. There is also a need for a material dispensing system that reduces costs associated with operation and maintenance. There is yet another need for a material dispensing system that improves the ability to modularize the dispensing system to provide a wider range of uniform material pattern widths across a moving substrate. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes the foregoing and other shortcomings and drawbacks of the material dispensing systems and methods heretofore known. While the invention will be described in connection with certain embodiments, it will be understood that the invention is not limited to these embodiments. On the contrary, the invention includes all alternatives, modifications and equivalents as may be included within the spirit and scope of the present invention. 
     The present invention is directed to a material dispensing system and method for use in applying in a controlled manner a fibrous material in a desired pattern on a moving substrate. The material dispensing system has a source of fluid material to be applied and a source of pressurized air that are connected to a material dispensing head. The material dispensing head has a fluid manifold connected to the source of material, an air manifold connected to the source of pressurized air, and a dispensing module having an upper dispensing body and a lower modular die assembly mounted to one end of the dispensing body. The dispensing body is connected to the fluid manifold for delivering fluid in a controlled manner to the die assembly. The modular die assembly includes a series of aligned material outlets that emit the fluid in a series of spaced strands toward a substrate. The dispensing body is connected to the air manifold for delivering pressurized air in a controlled manner to the die assembly. The pressurized air is used to draw down and attenuate the strands to form fibers that oscillate in a generally transverse plane relative to the direction of travel of the moving substrate. The oscillation of the fibers provides a uniform pattern of fibrous material on the moving substrate. The pressurized air between the material outlets also separates the strands during the critical draw down phase to prevent entanglement of adjacent strands. The orientation of the air and material outlets in accordance with the principles of the present invention improves control of the dispensed material to form a desired pattern on the moving substrate. 
     In accordance with one aspect of the present invention, the modular die assembly has a die block mounted to a lower end of the dispensing body. The die block has a seat for mounting a pattern die and sealing plate to a lower end of the die block. Material passages are formed in the die block for delivering viscous material from the dispensing body to the pattern die. Air passages are also formed in the die block for delivering pressurized air from the air manifold to the pattern die. The sealing block is mounted to provide a seal between the various components of the modular die assembly. 
     The pattern die has a series of spaced openings that are preferably aligned on a common axis along a lower surface of the pattern die. A nozzle is preferably fitted into each spaced opening. The pattern die has material passages that communicate with the material passages in the die block for delivering the viscous material to the nozzles. The nozzles receive the viscous material from the material passages in the pattern die, and emit the material as spaced strands. The pattern die further includes a series of spaced air outlets that are also preferably aligned on a common axis along the lower surface of the pattern die. The pattern die air passages communicate with the air passages in the die block and provide pressurized air to the air outlets. 
     In accordance with a principle aspect of the present invention, the patten die includes a pair of outer liquid material outlets and a plurality of inner liquid material outlets therebetween spaced along a common axis at one end of the pattern die for dispensing a plurality of strands of liquid material toward the substrate. The pattern die further includes a pair of air outlets associated with each of the inner liquid material outlets and a single air outlet associated with each of the outer liquid material outlets for emitting pressurized air that is operable to oscillate the dispensed strands in directions predominantly parallel with the common axis of the liquid material outlets during flight toward the substrate to form an overlapping pattern of liquid material on the moving substrate. 
     In operation, the pattern die emits the viscous material preferably from the nozzles as spaced strands toward a surface of the moving substrate. The pattern die also emits air generally between the strands to draw down and attenuate the strands into small fibers that are deposited uniformly onto the moving substrate. 
     The orientation of the material outlets and air outlets in accordance with the principles of the present invention preferably causes the fibers to oscillate in a generally cross-machine direction that improves blending of adjacent fibers. The air between the material outlets also prevent entanglement of adjacent strands during the critical draw down phase to reduce “shot” formation on the moving substrate. Additionally, the orientation of the material outlets and air outlets requires less volume and velocity of air to create a uniform pattern of fibrous on the web. With less volume and velocity of air, the material dispensing system reduces undesirable “fly” formation and lowers operational and maintenance costs of the material dispensing system. Moreover, the orientation and operation of the material outlets and air outlets improves the ability to modularize the dispensing system to provide a wider range of uniform pattern widths across a moving substrate. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
     FIG. 1A is a functional block diagram of a material dispensing system in accordance with the principles of the present invention. 
     FIG. 1B is an exploded view of a modular die assembly in accordance with the principles of the present invention showing the die assembly mounted on a lower end of a material dispensing body; 
     FIG. 2 is a cross-sectional view, taken along line  2 — 2  of FIG. 1B, showing one embodiment of the die assembly, and mounting of the various die assembly components; 
     FIG. 3 is a cross-sectional view, taken along line  3 — 3  of FIG. 2, illustrating a pattern die in accordance with one embodiment of the present invention, and the material dispensing pattern created by the die assembly across the width of a moving substrate; 
     FIG. 3A is a side view, taken along line  3 A— 3 A of FIG. 3, illustrating the material dispensing beam created by the die assembly; 
     FIG. 3B is a diagrammatic top plan view, taken along line  3 B— 3 B of FIG. 3, illustrating a material dispensing footprint created by the die assembly; 
     FIG. 4 is a bottom view of the pattern die illustrated in FIG. 3, taken along line  4 — 4  of FIG. 3; 
     FIG. 5 is a view similar to FIG. 3, illustrating a pattern die in accordance with a second embodiment of the present invention; 
     FIG. 6 is a bottom view of the pattern die illustrated in FIG. 5, taken along line  6 — 6  of FIG. 5; 
     FIG. 7 is a view similar to FIG. 3, illustrating a pattern die in accordance with a third embodiment of the present invention; 
     FIG. 7A is a perspective view of a nozzle insert shown in FIG. 7; 
     FIG. 8 is a bottom view of the pattern die illustrated in FIG. 7, taken along line  8 — 8  of FIG. 7; 
     FIG. 9 is a view similar to FIG. 3, illustrating a pattern die in accordance with a fourth embodiment of the present invention; 
     FIG. 10 is a bottom view of the pattern die illustrated in FIG. 9, taken along line  10 — 10  of FIG. 9; 
     FIG. 11 is a view similar to FIG. 3, illustrating a pattern die in accordance with a fifth embodiment of the present invention; 
     FIG. 11A is a perspective view of a nozzle insert shown in FIG. 11; 
     FIG. 12 is a bottom view of the pattern die illustrated in FIG. 11, taken along line  12 — 12  in FIG. 11; 
     FIG. 13 is diagrammatic cross-sectional view of a modular die assembly in accordance with an alternative embodiment of the present invention; 
     FIG. 14 is a bottom view of a pattern die illustrated in FIG. 13, taken along line  14 — 14  of FIG. 13; 
     FIG. 15 is an exploded view of a modular die assembly in accordance with a third embodiment of the present invention; 
     FIG. 15A is an enlarged view, in elevation, of the encircled area  15 A in FIG. 15; 
     FIG. 16 is a cross-sectional view of the modular die assembly of FIG. 15 fully assembled, showing mounting of the various die components 
     FIG. 17 is a view similar to FIG. 3, illustrating a pattern die in accordance with a sixth embodiment of the present invention; and 
     FIG. 18 is a bottom view of the pattern die illustrated in FIG. 17, taken along line  18 — 18  in FIG.  17 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the figures, and to FIG. 1A in particular, an overall material dispensing system  2  in accordance with the principles of the present invention is shown for dispensing a pattern of material on a moving substrate. For purposes of simplifying description of the present invention, the preferred embodiment will hereinafter be described in relation to the dispensing of hot melt thermoplastic adhesives, but those skilled in the art will readily appreciate application of the present invention to dispensing of other materials as well such as polymer and rubber based sealants and adhesive based materials. Material dispensing system  2  includes a source of material  4  and a source of pressurized air  6  that are each connected to a material dispensing head  8  through suitable delivery hoses or conduits  10   a  and  10   b,  respectively. Material source  4  may be, for example, an unloader and melter having a suitable hopper, melting grid and pump for delivering heated, viscous hot melt adhesive to the material dispensing head  8 . Air source  6  may be a compressor or other suitable device for delivering pressurized air to the material dispensing head  8  as will be appreciated by those skilled in the art. 
     Material dispensing head  8  preferably has a fluid manifold  12  connected to the source of material  4  through hose  10   a,  and an air manifold  14  connected to the source of pressurized air  6  through hose  10   b.  A dispensing module  16  is provided having an upper dispenser body  18  mounted to the fluid manifold  12 , and a lower modular die assembly  20  mounted to a lower end of the dispenser body  18 . Die assembly  20  preferably includes a die block  22 , a pattern die  24  and a sealing plate  26  that cooperate for purposes to be described in detail below. In operation, the dispenser body  18  receives viscous material from the fluid manifold  12  and delivers it in a controlled manner to the die assembly  20 . Die assembly  20  also receives pressurized air from the air manifold  14  and is operable to apply the viscous material as a fibrous pattern on a moving substrate as described in detail below. Of course, the source of pressurized air  6  could also be connected to dispensing body  18  and then to the die assembly  20 . 
     With reference to FIG. 1B, the die assembly  20  is shown in greater detail mounted to a lower end of dispenser body  18  in accordance with the principles of the present invention. As will be described in more detail below, die assembly  20  is particularly adapted to emit plural strands  27   a  of hot melt adhesive that are drawn down and attenuated into fibers  27   b  for deposition on a surface  28  of a moving substrate  30  (FIG.  3 ). As used herein, the term “fibrous material” refers to viscous material that is emitted from one or more material outlets in strand form, and which strands are drawn down or attenuated by pressurized air to form smaller diameter fibers. The fibers  27   b  can be of almost any diameter, but for hot melt adhesive applications, the diameters are typically in the range of 200 microns or less. It will be appreciated that other diameters are possible depending on the specific dispensing application. 
     As best understood with reference to FIG. 2, dispenser body  18  is adapted to provide a controlled continuous or intermittent flow of hot melt adhesive to the die assembly  20 . Dispenser body  18  is mounted to the heated fluid manifold  12 , and includes an adhesive cavity (not shown) for receiving viscous hot melt adhesive from the manifold  12 . The air manifold  14  is mounted to a lower end of the fluid manifold  12  through fasteners (not shown) that extend through a spacer  31  mounted between the fluid and air manifolds  12  and  14 , respectively. The air manifold  14  is formed with an air inlet line  32  fluidly connected to an air connector bore  34  formed in the die block  22 . Pressurized air source  6  is fluidly connected to the air inlet line  32  for providing controlled, continuous or intermittent air supply to the air connector bore  34  formed in the die block  22 . An O-ring  36  forms a fluid-tight seal between the die block  22  and the air manifold  14  at the junction of the air inlet line  32  and air connector bore  34 . It will be appreciated that while fluid manifold  12  and air manifold  14  are shown as separate components, they could be combined as a single unit. It will be further appreciated that the adhesive and air could be continuous or intermittent depending on the specific dispensing application. 
     As shown with further reference to FIG. 2, the modular die assembly  20  is mounted to the lower end of the dispenser body  18  via four fasteners  38  that extend through unthreaded bores (not shown) formed in the die assembly  20 . At their threaded ends, the set of fasteners  38  are connected to threaded bores (not shown) formed in the lower end of the dispenser body  18 . The dispenser body  18  is heated by conduction via its contact with fluid manifold  12 , and the die assembly  20  is heated by conduction via its contact with the dispenser body  18 . Dispenser body  18  is preferably a Model H200 hot melt adhesive dispenser commercially available from Nordson Corporation of Westlake, Ohio. The details of the structure and operation of Nordson&#39;s H200 hot melt adhesive dispenser may be found in U.S. Pat. Nos. 4,801,051 and 5,277,344, each of which is incorporated herein by reference in its entirety. The structure of the adhesive manifold  12 , air manifold  14  dispenser body  18  can assume any form without departing from the principles and scope of the present invention, and are discussed briefly herein for purposes of background only. It will be appreciated by those of ordinary skill in the art that while die assembly  20  is shown mounted to a lower end of dispenser body  18 , other mounting locations of die assembly  20  on dispenser body  18  are possible without departing from the spirit and scope of the present invention. 
     As shown with reference to FIGS. 1A-4, the die assembly  20  includes various die components that are collectively mounted to the lower end of the dispenser body  18  via the set of fasteners  38 . Preferably, the die assembly  20  includes the die block  22  having a mounting end  42  (FIG. 2) for fluidly connecting the die assembly  20  to the dispenser body  18 . The mounting end  42  extends into the adhesive cavity (not shown) of the dispenser body  14 , and is sealed with walls  43  of the adhesive cavity via an O-ring  44 . Die block  22  includes a vertical wall or surface  46  and a horizontal wall or surface  48  that define a seat  49  for mounting the pattern die  24  and sealing plate  26  to a lower end of the die block  22 , as best understood with reference to FIGS. 1A-2. Pattern die  24  and sealing plate  26  include respective apertures  54   a,    54   b,  and slots  56   a,    56   b  extending through the respective die components for receiving a pair of fasteners  58  that mount the components to the vertical wall  46  of die block  22 . It will be appreciated by those of ordinary skill in the art that slots  56   a,    56   b  formed through the pattern die and sealing plates  24  and  26  are provided to accommodate for thermal expansion of the various die components caused by heat generated during the hot melt adhesive dispensing process. 
     With further reference to FIGS. 1B and 2, pattern die  24  preferably includes a series of elongated, vertically and horizontally oriented air distribution channels  60   a  and  60   b  formed on one face  61  of the pattern die, and an elongated, horizontally oriented adhesive distribution channel  62  formed on the other face  63  of the pattern die for purposes to be described in detail below. Pattern die  24  preferably includes six (6) bores  64  formed through a lower surface  66  of the pattern die that extend upwardly and fluidly connect with six (6) transverse passages  68  (one shown in FIG. 2) extending horizontally inwardly from the elongated adhesive distribution channel  62 . Bores  64  preferably have a circular cross-section and are preferably aligned along an axis that is generally parallel to the longitudinal axis of the pattern die  24 . The bores  64  are also preferably spaced equidistantly along the lower surface  66  of the pattern die  24 . Bores  64  are sized to receive respective tubular nozzle inserts  70  that are inserted and frictionally engaged within the bores  64 . Each nozzle insert  70  has an elongated adhesive passage  72  that extends generally along the longitudinal axis of the nozzle insert. Each adhesive passage  72  preferably has a uniform cross-sectional shape between an upper surface  74  of the nozzle insert  70  and a conically-shaped material outlet  76  formed at a lower end of each nozzle insert  70  that extends below the lower surface  66 . It will be appreciated by those of ordinary skill in the art that adhesive passage  72  could be tapered without departing from the spirit and scope of the present invention. While adhesive passages  72  and material outlets  76  are shown having circular cross-sectional shapes, it is contemplated that square, rectangular or other cross-sectional shapes are possible for adhesive passages  72  and material outlets  76  without departing from the spirit and scope of the present invention. While six (6) bores  64  and six (6) nozzle inserts  70  are shown, it will be appreciated that fewer or more bores and nozzle inserts are possible depending on a specific material dispensing application. Moreover, it will be appreciated that while nozzle inserts  70  are preferred, they may be replaced with a series of adhesive passages drilled or otherwise formed in the lower surface  66  of pattern die  24 . 
     Pattern die  24  further preferably includes a pair of transverse passages  78  (one shown in FIG. 2) extending through the pattern die that fluidly connect with the respective pair of vertically oriented air distribution channels  60   a.  The pair of vertically oriented air distribution channels  60   a  are fluidly connected to the horizontally oriented air distribution channel  60   b  formed on the one face  61  of the pattern die  24  (FIGS.  1 B- 2 ). 
     In accordance with one embodiment of the present invention as shown with reference to FIGS. 2-4, the pattern die  24  includes a series of twelve (12) air passages  80  formed through the lower surface  66  of the pattern die that extend upwardly and fluidly connect with twelve (12) transverse passages  82  (one shown in FIG. 2) extending horizontally inwardly from the horizontally oriented air distribution channel  60   b.  Air passages  80  form air outlets  84  on the lower surface  66  of pattern die  24  that are preferably grouped in pairs in association with each material outlet  76 . In this preferred arrangement, it will be appreciated by those of ordinary skill in the art that for six (6) material outlets  76 , twelve (12) air passages  80  and twelve (12) transverse passages  82  are required. If the number of material outlets  76  increases or decreases, the number of air passages  80  and transverse passages  82  increases or decreases as well. 
     Preferably, the air passages  80  and air outlets  84  formed in association with the material outlets  76  are aligned generally along the axis of the material outlets  76 , with each pair of air outlets  84  being positioned on opposite sides of a respective material outlet  76  for purposes to be described in more detail below. While air passages  80  and air outlets  84  are shown having circular cross-sectional shapes, it is also contemplated that square, rectangular or other cross-sectional shapes are possible for air passages  80  and air outlets  84  without departing from the spirit and scope of the present invention. 
     It will be appreciated that while air passages  80  are shown as extending in pairs along the longitudinal length of the nozzle inserts  70 , the vertical orientation of the air outlets  84  may be changed without departing from the spirit and scope of the present invention. For example, each air passage  80  may angle inwardly toward the longitudinal axis of a respective nozzle insert  70 . Alternatively, only the outermost air passages  80  on the lower surface  66  of pattern plate  24  may be angled inwardly to control side edge formation of the dispensed pattern. Additionally, while the air outlets  84  are preferably aligned on the same axis as the material outlets  76 , other orientations of the air outlets  84  are possible that provide the same advantageous function of separating the strands  27   a  during the draw down phase and oscillating the fibers  27   b  in a generally cross-machine direction as described in detail below. For example, the air passages  84  may be staggered relative to the common axis of the material outlets  76  or positioned slightly off the common axis of the material outlets  76 . Moreover, while a pair of air outlets  84  is preferred with each material outlet  76 , more air outlets  84  per material outlet  76  are possible that provide the advantageous functions described herein. 
     As shown with reference to FIG. 2, die block  22  includes a stepped bore  85  and a supply passage  86  for delivering hot melt adhesive from the adhesive cavity (not shown) of dispenser body  18  to the elongated adhesive distribution channel  62  of pattern die  24 . A valve seat  88 , preferably made of carbide, is located in a lower portion of the stepped bore  85  that cooperates with a ball  90  formed on the lower end of a valve plunger  92  for providing controlled continuous or intermittent supply of hot melt adhesive to the adhesive distribution channel  62 . In this way, hot melt adhesive may be applied to the surface  28  of moving substrate  30  with well-defined cut-on and cut-off edges through the material outlets  76  in accordance with the present invention as will be described in more detail below or as a continuous pattern. It will be appreciated by those of ordinary skill in the art that while a single supply passage  86  is shown, the supply passage  86  may include two or more branches (not shown) that fluidly communicate with adhesive distribution panel  62 . In this configuration of the supply passage  86 , it is contemplated that a single fastener  58  could be used to mount the pattern die  24  and sealing plate  26  to the die block  22 . 
     With further reference to FIG. 2, die block  22  preferably includes a pair of air passages  94  (one shown) that extend between the air connector bore  34  and the respective pair of transverse passages  78  extending through the pattern die  24 . In this way, the pressurized air source  6  fluidly connected to air inlet line  32  and air connector bore  34  delivers air through each of the air outlets  84  formed in the pattern die  24  during operation of the material dispensing head  8  as will be described in more detail below. 
     As shown with reference to FIG. 2, sealing plate  26  is mounted having a planar face  96  in engagement with face  61  of pattern die  24  via the fasteners  58 . Pattern die  24  is mounted having opposite face  63  in engagement with vertical wall or surface  46  of die block  22 . It will be appreciated that fasteners  58  must be applied with sufficient torque to provide the necessary fluid seals between the sealing plate  26 , pattern die  24  and die block  22  to prevent loss of air or hot melt adhesive between the components of the modular die assembly  20 . 
     In operation of the material dispensing head  8 , as best understood with reference to FIGS. 2-4, the die assembly  20  is mounted above the surface  28  of moving substrate  30  with its longitudinal axis positioned generally transverse to the direction of travel of the substrate  30  (represented by directional arrows  98  in FIGS.  3 A and  3 B). Dispenser body  18  introduces hot melt adhesive into an upper portion of the stepped bore  85  formed in the die block  22 . With the ball  90  of valve plunger  92  in engagement with the valve seat  88 , adhesive is prevented from flowing into supply passage  86  and through the series of aligned nozzle inserts  70 . As the valve plunger  92  is forced upwardly during operation of the dispenser body  18  in a known manner to disengage ball  90  from seat  88 , hot melt adhesive is directed along flow paths defined by the supply passage  86 , adhesive distribution channel  62 , transverse passages  68 , and adhesive passages  72  formed in the nozzle inserts  70 . The hot melt adhesive is emitted through the material outlets  76  of the nozzle inserts  70  as strands  27   a  that are directed toward the surface  28  of moving substrate  30 . It will be appreciated by those skilled in the art that while a single dispensing module  16  is illustrated and described herein for applying fluid material such as hot melt adhesive on substrate  30 , a series of dispensing modules  16 , each with its associated dispenser body  18  and die assembly  20 , may be mounted in side-by-side relationship to extend across a wide range of substrate widths and thereby provide a wide range of material dispensing pattern widths. 
     At the same time that hot melt adhesive is emitted through the material outlets  76  in strand form, pressurized air is directed along flow paths defined by the air passages  94 , transverse passages  78 , vertically oriented air distribution channels  60   a,  horizontally oriented air distribution channel  60   b,  transverse passages  82 , and air passages  80  formed through the lower surface  66  of pattern die  24 . The pressurized air is emitted through the air outlets  84  positioned on opposite sides of each material outlet  76 , as represented diagrammatically by arrows  100  in FIG.  4 . 
     Further referring to FIGS. 2,  3 A,  3 B, the pressurized air emitted from each pair of air outlets  84  associated with a respective material outlet  76  serves several functions. First, the pressurized air from each air outlet pair draws down and attenuates each strand  27   a  of hot melt adhesive as it emits from a material outlet  76 . The attenuated strands  27   a  preferably form fibers  27   b  having a diameter of less than 200 microns on the surface  28  of the moving substrate  30  for hot melt dispensing applications. The pressurized air emitted from each air outlet  84  also serves to separate adjacent strands  27   a  during the critical draw down phase to reduce “shot” formation on the moving substrate  30 . Moreover, the pressurized air serves to oscillate the fibers  27   b  generally in a plane defined by the air outlets  84  associated with each material outlet  76 . 
     When the air outlets  84  are formed on the same axis as the material outlets  76 , the pressurized air causes the fibers  27   b  to oscillate generally in a plane transverse to the travel direction  98  of moving substrate  30  (i.e., in a cross-machine direction). The strands  27   a  are emitted from respective material outlets  76  and form side-by-side fiber beams  102  (FIGS. 3 and 3A) that overlap along adjacent edges to define generally oval placement patterns  104  (FIG. 3B) of hot melt adhesive on the upper surface  28  of moving substrate  30 . As each oval  104  has its longitudinal axis aligned generally transverse to the travel direction  98  of moving substrate  30 , and as adjacent edges of the ovals  104  overlap, the deposited fibers  27   b  blend to form a uniform hot melt adhesive pattern across the upper surface  28  of moving substrate  30 . While oval patterns  104  are shown as the preferred displacement pattern to form a small dispensing footprint for each material outlet  76 , it will be appreciated that other pattern cross-section shapes are possible. 
     To achieve a preferred uniform pattern of adhesive on the moving substrate  30 , a spacing is provided between adjacent material outlets  76 , designated D 1  in FIG. 4, preferably within the range of about 0.050 and about 0.250 in. for hot melt adhesive applications. Spacing values less than the preferred lower limit of the range may cause adjacent strands  27   a  to interfere or entangle in an undesirable fashion, while values above the preferred upper limit of the range may not provide the necessary blending to achieve a uniform pattern. Most preferably, the spacing D 1  is within the range of about 0.100 and about 0.200 in. for hot melt adhesive applications. 
     A spacing is also provided between each air outlet  84  and its associated material outlet  76 , designated D 2  in FIG. 4, preferably within the range of about 0.015 and about 0.080 in. for hot melt adhesive applications. Spacing values less than the preferred lower limit of the range may result in a less stable formation of fibers  27   b,  while values above the preferred upper limit of the range may not provide the necessary fiber oscillation amplitude to blend adjacent fibers  27   b  to achieve a uniform pattern. Most preferably, the spacing D 2  is within the range of about 0.030 and about 0.060 in. for hot melt adhesive applications. 
     When material outlets  76  are formed having circular cross-sectional shapes, a preferred diameter of the material outlets  76  is within the range of about 0.010 and about 0.030 in. for hot melt adhesive applications. Material outlet side diameters less than the preferred lower limit of the range may be susceptible to clogging, while diameters above the preferred upper limit of the range may not create sufficient backpressures necessary to produce consistent diameter fibers  27   b  on the substrate  30 . Most preferably, the diameter of the material outlets  76  is within the range of about 0.016 and about 0.024 in. for hot melt adhesive applications. It will be appreciated that other cross-sectional shapes for the material outlets  76 , such as square or rectangular cross-sectional shapes, and other diameters are possible without departing from the spirit and scope of the present invention. 
     When air outlets  84  are formed having a circular cross-sectional shape, a preferred diameter of the air outlets  84  is within the range of about 0.010 and about 0.050 in. for hot melt adhesive applications. Air outlet diameters less than the preferred lower limit of the range may not provide sufficient drawdown and formation of the fibers  27   b,  while diameters above the preferred upper limit of the range may not provide any further beneficial draw down or attenuation of the strands  27   a.  Most preferably, the diameter of the air outlets  84  is within the range of about 0.012 and about 0.030 in. for hot melt adhesive applications. It will be appreciated that other cross-sectional shapes for the air outlets  84 , such as square, crescent or rectangular cross-sectional shapes, and other side dimensions are possible without departing from the spirit and scope of the present invention. 
     In another embodiment of the present invention, as best understood with reference to FIGS. 5 and 6, a modified pattern die  150  is shown. All other components of the die assembly  20  are generally unchanged. In this embodiment, pattern die  150  preferably includes six (6) bores  164  formed through the lower surface  166  of the pattern die that extend upwardly and fluidly connect with the six (6) transverse passages (one shown in FIG. 2) extending horizontally inwardly from the adhesive distribution channel  62 . The bores  164  are equidistantly spaced along the lower surface  166  and have a circular cross-section. The bores  164  are also preferably aligned along an axis that is generally parallel to the longitudinal axis of the pattern die. The bores  164  are sized to receive respective tubular inserts  170  that are inserted and frictionally engaged within the bores  164 . Six (6) oblong bores  106  are formed through the lower surface  166  of the pattern die  150  that extend upwardly and fluidly connect with the twelve (12) transverse passages  82  (one shown in FIG. 2) extending horizontally inwardly from the horizontally oriented air distribution channel  60   b.  The oblong bores  106  are equidistantly spaced, and are preferably aligned with their respective longitudinal axes aligned along an axis that is also generally parallel to the longitudinal axis of the pattern die  150  and coincident with the axis of bores  164 . In this way, crescent-shaped air outlets  184  are formed on opposite sides of each material outlet  176  by a wall  108  of the oblong bores  106  and an outer cylindrical surface  110  of the tubular inserts  170 . The air outlets  184  and material outlets  176  function substantially as described in detail above to draw down and attenuate each strand  27   a  of hot melt adhesive as it emits from a material outlet  176 . The spacing distance D 2  between each air outlet  184  and a respective material outlet  176  is defined by the thickness of the tubular wall  112  of the nozzle insert  170 . It will be appreciated that the oblong bores  106  of this embodiment eliminate the need to form the twelve (12) air passages  80  associated with the pattern die  24  of FIGS. 1B-4, thereby simplifying overall manufacturing of the pattern die. 
     In another alternative embodiment of the present invention, as best understood with reference to FIGS. 7,  7 A and  8 , a modified pattern die  250  is shown. All other components of the die assembly  20  are generally unchanged. In this embodiment, the nozzle inserts  270  are slightly enlarged (FIG.  7 A), and include an annular air channel  214   a  and a pair of elongated, recessed air channels  214   b  formed in the tubular wall  212  of the each nozzle insert  270 . The nozzle inserts  270  are received and frictionally engaged in six (6) bores  264  formed through the lower surface  266  of the pattern die  250  as described in detail above. The annular air channels  214   a  fluidly communicate with six (6) transverse passages (not shown) extending horizontally inwardly from the horizontally oriented air distribution channel  60   b  and fluidly connected to the bores  264 . Each pair of air channels  214   b  are preferably formed on opposite sides of each adhesive passage  272  extending through the nozzle insert  270 . The nozzle inserts  270  are positioned in the six (6) bores  264  with each pair of air channels  214   b  forming a pair of air outlets  284  with a cylindrical wall of the bores  264 . Preferably, each pair of air outlets  284  is formed on opposite sides of a respective material outlet  276 , and air outlets  284  and material outlets  276  are aligned along an axis that is generally parallel to the longitudinal axis of the pattern die  250 . The air outlets  284  and material outlets  276  function substantially as described in detail above to draw down and attenuate each strand  27   a  of hot melt adhesive as it emits from a material outlet  276 . It will be appreciated that the tubular nozzle inserts  270  of this embodiment reduce the number of transverse passages  82  that need to be formed as well as eliminating the need to form the twelve (12) air passages  80  associated with the pattern die  24  of FIGS. 1A-4, thereby also simplifying overall manufacturing of the pattern die. 
     In yet another alternative embodiment of the present invention, as best understood with reference to FIGS. 9 and 10, a modified pattern die  350  is shown. All other components of the die assembly  20  are generally unchanged. In this embodiment, the nozzle inserts  370  are slightly enlarged and include an annular air channel  316   a  and a pair of elongated air channels  316   b  formed through the tubular wall  312  of the each nozzle insert  370 . The nozzle inserts  370  are received and frictionally engaged in six (6) bores  364  formed through the lower surface  366  of the pattern die  350  as described in detail above. The air channels  316   a  fluidly communicate with six (6) transverse passages (not shown) extending horizontally inwardly from the horizontally oriented air distribution channel  60   b  and fluidly connected to the bores  364 . Each pair of air channels  316   b  are preferably formed on opposite sides of the adhesive passage  372  extending through each nozzle insert  370 . The nozzle inserts  370  are positioned in the six (6) bores  364  with each pair of air channels  316   b  forming a pair of air outlets  384  on opposite sides of a respective material outlet  376 . Preferably, the air outlets  384  and material outlets  376  are aligned along an axis that is generally parallel to the longitudinal axis of the pattern die  350 . The air outlets  384  and material outlets  376  function substantially as described in detail above to draw down and attenuate each strand  27   a  of hot melt adhesive as it emits from a material outlet  376 . It will be appreciated that where the elongated air channels  316   b  are preformed in each nozzle insert  370 , the air channels  316   b  are sealed off from the adhesive passage  372 . 
     In still yet another alternative embodiment of the present invention, as best understood with reference to FIGS. 11,  11 A and  12 , a modified pattern die  450  is shown. All other components of the die assembly  20  are unchanged. In this embodiment, each air nozzle insert  470  includes an annular air channel  414   a  and a pair of planar faces  418  formed on opposite sides of the nozzle insert  470 . The nozzle inserts  470  are received and frictionally engaged in six (6) bores  464  formed through the lower surface  466  of the pattern die  450 . The annular air channels  414   a  fluidly communicate with six (6) transverse passages (not shown) extending horizontally inwardly from the horizontally oriented air distribution channel  60   b  and fluidly connected to the bores  464 . The nozzle inserts  470  are positioned in the six (6) bores  464  with each planar face  418  forming a pair of air outlets  484  with a cylindrical wall of the bores  464 . The air outlets  484  are formed on opposite sides of a respective material outlet  476 , and the air outlets  484  and material outlets  476  are preferably aligned along an axis that is generally parallel to the longitudinal axis of the pattern die  450 . The air outlets  484  and material outlets  476  function substantially as described in detail above to draw down and attenuate each strand  27   a  of hot melt adhesive as it emits from a material outlet  476 . 
     Referring now to FIGS. 13 and 14, a modular die assembly  500  in accordance with an alternative embodiment of the present invention is shown. Die assembly  500  includes a die block  502  mounted to a lower end of a dispenser body  504 , and a pattern die  506  mounted to a lower planar face  508  of the die block  502 . It will be appreciated that the dispenser body  504  is similar in structure and operation to the dispenser body  18  described in detail above. Die block  502  has a mounting end  510  for fluidly connecting the die assembly  500  to the dispenser body  504 . The mounting end  510  extends into the adhesive cavity (not shown) of the dispenser body  504 , and is sealed with walls of the adhesive cavity via an O-ring  512 . 
     Die body  502  has a stepped bore  514  and a supply passage  516  for delivering hot melt adhesive from the adhesive cavity to an elongated adhesive distribution channel  518  formed in the lower planar face  508  of the die body  502 . A pair of air passages  520  (one shown in FIG. 13) is formed in the die body  502  to extend between an air connector bore  522  and the lower planar face  508  of the die body  502 . A set of fasteners  524  extend through the die body  502  and pattern die  506  to mount the die assembly  500  to the dispenser body  504 . 
     Pattern die  506  preferably includes a series of six (6) bores  526  (one shown in FIG. 13) formed through a lower surface  528  of the pattern die that extend upwardly and fluidly connect with six vertically oriented (6) passages  530  (one shown in FIG. 13) extending from an upper planar face  532  of the pattern die  506 . Bores  526  preferably have a circular cross-section and are preferably aligned along an axis that is generally parallel to the longitudinal axis of the pattern die  506 . The bores  526  are also preferably spaced equidistantly along the lower surface  528  of the pattern die  506 , and are sized to receive respective tubular nozzle inserts  534  that are inserted and frictionally engaged within the bores  526 . Each nozzle insert  534  has an elongated adhesive passage  536  that extends generally along the longitudinal axis of the nozzle insert. Each adhesive passage  536  preferably has a uniform cross-sectional shape between an upper surface  538  of the nozzle insert  534  and a conically-shaped material outlet  540  formed at a lower end of each nozzle insert  534  that extends below the lower surface  528  of pattern die  506 . Of course, the adhesive passages  536  could be tapered within the spirit and scope of the present invention. 
     Pattern die  506  further preferably includes an elongated air distribution channel  542  formed in the upper face  532  of the die head. In accordance with one embodiment of the present invention, the pattern die  506  includes a series of twelve (12) passages  544  (one shown in FIG. 13) that are each fluidly connected at one respective end to the air distribution channel  542 . The other respective ends of the passages  544  are fluidly connected to twelve (12) air passages  546  (FIG. 14) that are formed through the lower surface  528  of the pattern die  506 . 
     In operation, the die assembly  500  is mounted above a surface  548  of a moving substrate  550  with its longitudinal axis positioned generally transverse to the direction of travel of the moving substrate  550  (represented by directional arrow  552  in FIG.  13 ). Dispenser body  504 , similar to dispenser body  18  described in detail above, introduces hot melt adhesive into an upper portion of the stepped bore  514  formed in the die body  502 . In an “on” state, hot melt adhesive is directed along flow paths defined by the supply passage  516 , adhesive distribution channel  518 , vertical passages  530 , and adhesive passages  536  formed in the nozzle inserts  534 . The hot melt adhesive is emitted through material outlets  540  (FIG. 14) of the nozzle inserts  534  as strands  554   a  that are directed toward surface  548  of moving substrate  550 . 
     At the same time that hot melt adhesive is emitted through the material outlets  540  in strand form, pressurized air is directed along flow paths defined by the air passages  520 , air distribution channel  542 , passages  544 , and air passages  546  formed through the lower surface  528  of pattern die  502 . The pressurized air is emitted through air outlets  556  (FIG. 14) positioned on opposite sides of each material outlet  540  as described in detail above. Die assembly  500  is operable to emit the strands  554   a  of hot melt adhesive that are drawn down and attenuated into fibers  554   b  for deposition on the surface  548  of the moving substrate  550  as described above with reference to the embodiment of the die assembly  20  of FIGS. 1-12. It will be appreciated by those skilled that the art that the nozzle inserts  534  and air passages  546  may be modified to incorporate the configurations shown and described above with reference to FIGS. 1-12. Moreover, it will be appreciated that while nozzle inserts  534  are preferred, they may be replaced with a series of adhesive passages drilled or otherwise formed in the lower surface  528  of the pattern die  506 . 
     FIGS. 15,  15 A and  16  illustrate a modular die assembly  600  in accordance with another alternative embodiment of the present invention. Die assembly  600  is mounted to a lower end of a dispenser body  602  and includes a die block  604  similar to the die block  22  described in detail above, a distribution plate  606 , a pattern die  608 , and a sealing plate  610 . The distribution plate  606 , pattern die  608  and sealing plate  610  are mounted within a seat  612  defined by a vertical wall or surface  614  and a horizontal wall or surface  616  formed in die block  604 . It will be appreciated that the dispenser body  602  is similar in structure and operation to the dispenser body  18  described in detail above. 
     As best understood with reference to FIGS. 15 and 16, each of the distribution plate  606 , pattern die  608  and sealing plate  610  includes a respective pair of apertures  618  extending through the die components for receiving a pair of fasteners  620  that mount the components to the vertical wall  614  of die block  604 . Distribution plate  606  is mounted having a planar face  622  in engagement with the vertical wall or surface  614  of die block  604 , and includes a pair of transverse air passages  624  extending through the plate  606  that fluidly connect with a respective pair of air passages  626  (one shown in FIG. 16) formed in die block  604 . Distribution plate  606  further includes a transverse adhesive passage  628  extending through the plate  606  that fluidly connects with an adhesive supply passage  630  formed in die block  604  (FIG.  16 ). For purposes to be described in greater detail below, a pair of vertically oriented air distribution channels  632   a,  and an elongated, horizontally oriented air distribution channel  632   b,  are formed in an opposite face  634  of distribution plate  606 . 
     Pattern die  608  is mounted having a planar face  636  in engagement with the opposite face  634  of the distribution plate  606 . As will be described in greater detail below, pattern die  608  includes respective upper and lower pairs of transverse air passages  638   a  and  638   b  that extend through the pattern die  608 , with the upper pair of air passages  638   a  fluidly connected to the pair of air passages  624  in distribution plate  606 , and each of the lower pair of air passages  638   b  fluidly connected to a respective one of the pair of vertically oriented air distribution channels  632   a  formed in the face  634  of die block  606 . Pattern die  608  further includes an elongated, horizontally oriented adhesive distribution channel  640  formed in face  636  that fluidly connects with the transverse adhesive passage  628  formed in distribution plate  606 . 
     As shown in FIGS. 15A and 16, pattern die  608  preferably includes six (6) adhesive passages  642 , drilled or otherwise formed, that extend from a lower end  644  of the pattern die  608  and fluidly connect with the elongated, horizontally oriented adhesive passage  640  formed in pattern die  608 . Each adhesive passage  642  terminates in a material outlet  646  at the lower end  644  of the pattern die  608 . The material outlets  646  are preferably aligned along a common axis and are equidistantly spaced at the lower end  644  of the pattern die  608 . Of course, it will be appreciated that the adhesive passages  642  may be replaced with tubular nozzle inserts (not shown), as described in detail above, without departing from the spirit and scope of the present invention. Air outlets  648  are formed between each material outlet  646  by respective angularly-shaped, upper and lower cutouts  650   a  and  650   b  formed on the lower end  644  and on opposite faces  636  and  652  of the pattern die  608  for purposes to be described in detail below. 
     As shown in FIGS. 15 and 16, the sealing plate  610  includes a pair of elongated, vertically oriented air distribution channels  654   a  and an elongated, horizontally oriented air distribution channel  654   b  formed in plate face  656  that engages face  652  of pattern die  608 . Each of the vertically oriented air distribution channels  654   a  fluidly connects with an upper and lower air passage  638   a,    638   b  of each respective pair of air passages  638   a,    638   b  formed in the pattern die  608 . As shown phantom in FIG. 16, the upper cutouts  650   a  on one side of pattern die  608  fluidly connect with the horizontally oriented air distribution channel  654   b  of sealing plate  610 , while the upper cutouts  650   a  on the other side of pattern die  608  fluidly connect with the horizontally oriented air distribution channel  632   b  of distribution plate  606 . 
     In operation, the die assembly  600  is mounted above a surface of a moving substrate (not shown) with its longitudinal axis preferably positioned generally transverse to the direction of travel of the moving substrate (not shown). In an “on” state of dispenser body  602 , hot melt adhesive is directed along flow paths defined by the supply passage  630 , adhesive passage  628 , adhesive distribution channel  640 , and vertically oriented adhesive passages  642 . The hot melt adhesive is emitted through the material outlets  646  as strands (not shown) that are directed toward the surface of moving substrate (not shown), similar to strands  27   a  described in detail above. 
     At the same time that hot melt adhesive is emitted through the material outlets  646  in strand form, pressurized air is directed along flow paths defined by the air passages  626 , air passages  624 , upper air passages  638   a,  vertically oriented air distribution channels  654   a,  horizontally oriented air distribution channel  654   b,  lower air passages  638   b,  vertically oriented air distribution channels  632   a,  and horizontally oriented air distribution channel  632   b.    
     As described above, the horizontally oriented air distribution channel  654   a  of distribution plate  606  fluidly connects with upper cutouts  650   a  on one side of pattern die  608 , while the horizontally oriented air distribution channel  654   b  of sealing plate  610  fluidly connects with upper cutouts  650   a  on the opposite side of pattern die  608 . In this way, pressurized air is emitted through the air outlets  648  formed between each of the material outlets  646 . The air outlets  648  and material outlets  646  function substantially as described in detail above to draw down and attenuate each strand (not shown) of hot melt adhesive as it emits from a material outlet  646 . 
     In yet another embodiment of the present invention, as best understood with reference to FIGS. 17 and 18, a modified pattern die  750  is shown. All other components of the die assembly  20  are generally unchanged. In this embodiment, pattern die  750  preferably includes six (6) bores  764  formed through the lower surface  766  of the pattern die that extend upwardly and fluidly connect with the six (6) transverse passages (one shown in FIG. 2) extending horizontally inwardly from the adhesive distribution channel  62 . The bores  764  are equidistantly spaced along the lower surface  766  and have a circular cross-section. The bores  764  are also preferably aligned along an axis that is generally parallel to the longitudinal axis of the pattern die. The bores  764  are sized to receive respective tubular inserts  770   a  and  770   b  that are inserted and frictionally engaged within the bores  764 . The tubular inserts  770   a  define a pair of outer liquid material outlets  776   a,  while the tubular inserts  770   b  define inner liquid material outlets  776   b.  Four (4) oblong bores  780  and two (2) crescent bores  782  are formed through the lower surface  766  of the pattern die  150  that extend upwardly and fluidly connect with ten (10) transverse passages (not shown) extending horizontally inwardly from the horizontally oriented air distribution channel  60   b.  The ten (10) transverse passages (not shown) are similar to the twelve (12) transverse passages  82  described in detail above in connection with FIG.  2 . The oblong bores  780  are equidistantly spaced, and are preferably aligned with their respective longitudinal axes aligned along an axis that is also generally parallel to the longitudinal axis of the pattern die  750  and coincident with the axis of bores  764 . In this way, crescent-shaped air outlets  784   a  are formed on opposite sides of each material outlet  776   a  by a wall  708   a  of the oblong bores  780  and an outer cylindrical surface  710  of the tubular inserts  770   a.  Additionally, crescent-shaped air outlets  784   b  are formed axially inwardly of each material outlet  776   b  by a wall  708   b  of the crescent bores  782  and the outer cylindrical surface  710  of the tubular inserts  770   b.  The air outlets  784   a,    784   b  and material outlets  776   a,    776   b  function substantially as described in detail above to draw down and attenuate each strand  27   a  of hot melt adhesive as it emits from a material outlet  776   a,    776   b.  By eliminating air outlets axially outwardly of each outer material outlet  776   a,  “necking” of the dispensed pattern, i.e., a reduction in the overall width of the dispersed pattern in the cross-machine direction, is reduced. 
     It will be appreciated by those skilled in the art that the material dispensing system  2  of the present invention provides improved control of dispensed material patterns on a moving substrate. The decreased volume of air required to produce a uniform layer of material on the substrate reduces the formation of undesirable “fly”, and also reduces operational and maintenance costs of the material dispensing system  2 . Additionally, the ability to increase the spacing between adjacent material outlets  76  per dispensing module  16  to form a uniform layer on the substrate (or to reduce the number of material outlets  76  per dispensing module  16 ) reduces the formation of undesirable “shot” during the critical draw down phase. The orientation of the dispensed pattern in narrow beams reduces the dispensed pattern footprint for improved pattern control. Moreover, the orientation and operation of the material outlets  76  and air outlets  84  improves the ability to modularize the dispensing system. 
     While the present invention has been illustrated by a description of various embodiments and while these embodiments have been described in considerable detail, it will be appreciated by those of ordinary skill in the art that departures may be made from such details without departing from the spirit or scope of applicants&#39; invention. For example, while the terms “upper”, “lower”, “above” and “below” have been used herein to discuss one embodiment of the present invention, it will be understood that other orientations of the die components and substrate are possible without departing from the spirit and scope of the present invention. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method, and illustrative example shown and described. 
     While the present invention has been illustrated by a description of various embodiments and while these embodiments have been described in considerable detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method, and illustrative example shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicants&#39; general inventive concept.