Abstract:
A polymer is plasticized in a plasticizing unit and is thereafter fed into a transfer device which is moved into alignment with a clamping press which is remotely located from the plasticizing unit. The polymer from the transfer device is deposited on a carrier which moves into the forming device. An impress preforming device allows the carrier with the deposited polymer to be shaped in the mold or forming device. Alternatively, the transfer device can be connected with a chamber which is capable of coating continuous or chopped fibers which are deposited on a carrier in a continuous or chopped manner. The carrier with the fiber and polymer composite layer are shaped in the forming device.

Description:
FIELD OF INVENTION 
     This invention relates to a polymer transfer and deposition system and to a carrier transfer molding system where a carrier of a generally planar shape passes below a polymer deposition device where polymer is deposited on the carrier with the combined carrier and polymer moving to a forming device to produce an article of a desired shape. When more than one layer of polymer is deposited on the carrier, an insert is placed between the polymer layers. A surface layer is laminated to the top layer of polymer prior to moving into a forming device. 
     CROSS REFERENCE TO RELATED APPLICATIONS 
     This invention refers to a transport and deposition device and method as described in U.S. patent application Ser. No. 09/388,052 filed on Sep. 1, 1999, now U.S. Pat. No. 6,264,462. issued Jul. 24, 2001. 
     BACKGROUND OF INVENTION 
     This invention relates to a system including a combined carrier and deposited polymer that move into a forming device to produce an article of a desired shape. The carrier may collect more than one deposit or layer of polymer where an insert such as a rigid foam or honeycomb core is encapsulated by the polymer layers. Additionally, continuous strands of fiber reinforcement may be incorporated in the polymer phase. The carrier, as an example, is a film, foil, fiber construction or other support of a generally planar shape. The carrier provides a decorative surface in the finished shape, outdoor ultra-violet (UV) protection, fire retardency, improved chemical and permeation resistance, improved impact properties or just provides a sacrificial mechanism to move a deposited polymer into a forming device. Although a thermoset can be specified as the deposited polymer, a molten thermoplastic is the preferred choice. A method to deposit polymer onto a carrier in close proximity to one or more forming devices, to minimize heat loss time prior to forming the desired part, is described in my copending U.S. patent application, Ser. No. 09/388,052, now U.S. Pat. No. 6,264,462. The same disclosure describes a method to incorporate continuous fibers in the polymer composition. 
     Although the carrier process or method can produce a wide variety of sizes and shapes, the processing advantages become more apparent as the size of the finished part increases, typically in excess of one square meter. A prime thermosetting method used to produce large polymer composites utilizes cross-linking liquid resins to impregnate reinforcements under low pressures, either within a mixing head or pumping the liquid into a fiber preform. The combined composite solidifies as the liquid polymer cross-links. Large thermoplastic composites can be produced under low pressure by a softening a plastic sheet, then pulling a vacuum under a forming shape. These low pressure processes are generally used where production volumes are lower because of the lower productivity associated with these technologies. Injection molding was designed for high volume production of polymer shapes. However, the process requires higher molding pressures. For large parts, these pressure requirements can be substantial. The increasing equipment costs associated with the need to meet increased pressures has limited the use of injection molding in the production of large parts. 
     The polymer deposited on a carrier generally occupies or fills out a large area of the forming dies in a forming press, plus the pre-coating of the carrier by a deposited polymer, leads to a reduction in trapped gases between the carrier and the polymer. Because the polymer flows less within a forming device when compared to injection molding, the pressure requirements needed to produce an article with a finished shape are less than required with an injection molding machine. This reduced pressure allows pressure sensitive surface materials and cores to be incorporated in the finished composite shape without damage. The processing cycle of the carrier deposited polymer process is similar to an injection molding cycle based on the similar cooling times and distribution of polymer within the forming device. The carrier transfer lower pressure process combines the productivity and processing characteristics of injection molding with the ability to customize the desired finished surface; incorporate cores to improve stiffness, acoustic and insulation properties, and allow selective placement of continuous reinforcement to increase the stiffness and strength of the composite. 
     SUMMARY OF THE INVENTION 
     The present invention addresses a need in the art by providing a combined polymer matrix where the surface characteristics of the product can be customized, cores can be incorporated and, where needed, reinforcement impregnation to produce a whole new range of useful properties. A carrier, typically in a planar shape, passes below a polymer deposition device where a uniform layer of molten polymer is deposited on the carrier in close proximity to a forming device. The combined materials move into an opening in the forming device where the forming device closes on the materials to form the desired shape. 
     The carrier moves under a polymer deposition device that contains a predetermined amount of molten polymer based on the size of the deposition chamber. A ram within the chamber pushes the molten polymer out of an opening in the bottom of the chamber where the size and shape of the opening determines the deposited thickness, together with the speed of the ram and carrier. The molten polymer may be polypropylene, high density polyethylene, polyester, thermoplastic olefin or any other desired thermoplastic. The carrier can be low cost non-wovens such as spunbonded polyester and polyolefin or felt; a combination of a film and non-woven or foam; a fluoropolymer film such as Fluronated Ethylene Propylene (FEP) to improve fuel and gas permeation resistance or polyvinyl fluoride for fire retardency and UV resistance; a pre-printed film or a coated film to change the surface characteristics in the finished part or any other desired surface. The combined materials index in a straight line fashion into the forming press where the carrier is separated from a series of side clamps that support the carrier during the deposition and movement phase. Alternately, an undercarriage that holds the carrier in position during polymer deposition and movement into the forming device can support the carrier. A vacuum or clamps incorporated in the undercarriage would hold the carrier and deposited layer or layers of polymer during movement into the forming device, then disengage prior to removal of the undercarriage from the carrier and closing of the forming device. Outboard clamps located on opposite sides of the forming press and outside of the shaping molds would hold and position the combined carrier and deposited polymer as the forming device closed to produce the desired shape. Preferably, the undercarriage would be an insulator and have low surface friction characteristics. 
     In a second aspect, the carrier moves under the polymer deposition device in a direction away from the forming device as polymer is deposited on the carrier. Once clear of the deposition device, a multi-axis robot positions an insert on top of the deposited polymer layer. The carrier reverses direction, again passing under the polymer deposition device where a second coating or layer of polymer is deposited over the insert. The combined composite moves in a straight-line direction into the forming device to form a desired shape. The insert can be rigid foam, honeycomb, balsa or any other desired construction. 
     Alternately, two polymer deposition devices can align with each other in a manner where the carrier can pass under both devices in a straight-line direction with the forming device. The carrier first passes under the deposition device furthest from the forming device, then under the second deposition device where a second layer of polymer is deposited. The combined polymers and carrier move into the forming device where the desired shape is formed. Prior to the second deposit a multi-axis robot places an insert such as rigid foam or honeycomb on top of the first deposited layer prior to applying the second coating. The composition of the polymer being deposited from each deposition chamber can be the same or of a different polymer. 
     Using a secondary chamber that collects molten polymer from the deposition chamber, continuous fibers, discontinuous fibers or a combination of continuous and discontinuous fibers are fed into a chamber where the fibers are encapsulated by molten polymer under pressure and downward applied motion as described in my copending U.S. patent application, Ser. No. 09/388,052, now U.S. Pat. No. 6,264,462. The combined material is deposited in generally a planar shape on the carrier and moves into the forming device to produce the desired shape. 
     A second surface layer can be applied to the deposited polymer prior to entering the forming device. A multi-axis robot contains a vertical holding fixture with a curved edge on the side closest to the deposited polymer. The surface layer is positioned on the fixture with the edge extending into the curved area. The robot applies downwardly acting pressure on the curved edge where the forward movement of the deposited polymer on the carrier pulls the surface layer from the robot fixture. The curved edge can incorporate a roller feature that assists the movement of the second surface layer. Alternately, drive rollers or other suitable driving devices can assist the forward movement of the second surface layer during lamination to the top of the deposited polymer melt. 
     A mold consisting of a cavity or concave side and a core or convex side can be attached to a vertical action-forming device such as a clamping press. The desired polymer and carrier composition would be positioned between the cavity and core where the press would close to form the product determined by the shape of the cavity and core. The carrier side can be formed over either the cavity or core. One reason for forming the carrier over the core side would be to produce a chamber with the carrier on the inside area. Two chambers with matching edges would be aligned opposite each other and fused together after softening the surfaces of the carrier edges with a source of heat generation directed at the area to be fused. A set of holding fixtures would move the two mating half&#39;s together under pressure to insure full contact at the bond line. The resulting part would be a hollow device such as a liquid container. Interior and exterior required details would be incorporated in either section of the parts. The use of a fluoropolymer construction as the carrier would provide improved chemical and permeation resistance through the inside walls of the container. A specific example would be a plastic fuel tank with molded-in attachment features and low fuel vapor permeation. 
     Any of the various carrier and polymer combinations can be incorporated together to form a specific finished article or part. For example, the carrier can provide a decorative surface with the deposited polymer adding structure. The incorporation of a core such as rigid foam between polymer layers can increase the stiffness, insulation properties or other desirable characteristic in the combined composite. Continuous fiber reinforcement in one or both polymer deposits would increase the stiffness and strength of the composite. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic top view of the components that made up the transfer deposition device. 
     FIG. 2 is a cross-sectional view of the polymer distribution manifold taken along line  2 — 2  of FIG.  1 . 
     FIG. 3 is a cross-sectional view of the transport device taken along line  3 — 3  of FIG.  1 . 
     FIG. 4 is a schematic view of the preferred carrier moving below a plasticized polymer chamber where polymer is being deposited and a forming device is in line with the carrier and deposition chamber. 
     FIG. 5 is a schematic view of a multi-axis robot placing a rectangular insert on a polymer deposited carrier and a supporting undercarriage containing side clamps to hold the carrier and a deposition chamber that applies another polymer deposit when the undercarriage moves under the chamber to encapsulate the insert. 
     FIG. 6 is a schematic view of a robot positioned in front of a deposition chamber where a surface layer is released from the robot as a polymer deposited carrier and supporting undercarriage moves under the curved bottom section of robot guide while the robot applies pressure on the combined materials. 
     FIG. 7 is a perspective view of the robot guide of FIG. 6, with a roller located on the curved portion of the guide. 
     FIG. 8 is a schematic view of two deposition chamber in series with a polymer coated carrier moving under the outer chamber while a second polymer coated carrier with an insert on top moving under the inner deposition chamber where another deposited layer is applied. 
     FIG. 9 is a perspective view of an automotive fascia that combines a decorative surface carrier, a polymer deposited backing, a core material and a second continuous fiber filled back layer of polymer. 
     FIG. 10 is a schematic view of a forming device or a vertical acting clamping press containing upper and lower sections. 
     FIG. 11 is a cross-sectional view of two concave sides and carriers facing each other while in holding fixtures with external heat being applied to the edges. 
     FIG. 12 is a cross-sectional view of the two sections in a sealed state. 
     FIG. 13 is a perspective view of the sealed container, open at the end, with the carrier as the inside surface. 
     FIG. 14 is a cross-sectional view of a polymer deposited carrier being held in place by a vacuum system in the undercarriage, positioned within a forming device with a core forming section on the upper half and a cavity section on the bottom, side guides to move the undercarriage into the press and outboard clamps that position and hold the carrier over the cavity and core to allow the undercarriage to move out of the clamping device. 
     FIG. 15 is a cross-sectional view of a carrier adhering to a deposited polymer layer, a honeycomb core insert and a second layer of deposited polymer located over the insert. 
     FIG. 16 is a partial cross-sectional view of the transport device inserted to a polymer collection chamber, a layer of fiber being driven into the chamber and a carrier passing below the chamber. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIG. 1, where the polymer transfer and deposition device is designated by the letter A. It includes plasticating machine or extruder  10  shown with remotely located combinations of multiple or a plurality of clamp stations  12  and a plurality of single site clamping stations  14 . A dual outlet polymer distribution manifold  16  with shut off controls  28  for each outlet  30  is attached to the plasticating machine  10  while depositing the plasticized polymer into the chamber of a transport device  18 . Additional transport devices  20  are positioned in front of the clamping stations  12  and  14  for returning to the manifold  16  polymer dispensing outlet. The transport device guide or conveyor  22  handles the outer transport movement while transport device guide or conveyor  24  controls the inner transport movement. 
     The arrangement or layout of the clamping stations  12  and  14  are for illustrations purposes. As shown in FIG. 10, each vertical acting clamping station  14  includes mold sections  15  which are attached to vertically spaced apart platens  13  constituting a forming device. A fluid cylinder or actuator  25  is attached to the upper platen  13  for moving the platen  13  up and down on the guides  17 . The size and number of stations can be adjusted to meet a specific requirement. 
     The four illustrated transport devices  18  and  20  of FIG. 1 are shown with the inner, bottom transport device  20  serving clamping stations  12  and  14  on the bottom left side as illustrated. The top transport device  18  handles the upper left clamping station  14  as illustrated. The two outer transport devices  20  serve the outer top and bottom clamping stations  12  respectively as illustrated in FIG.  1 . One or more cylinders are attached to the transport devices  18 ,  20 , providing the pressure to move a ram  36  located within the transport chamber  34 , as shown in FIG.  3 . The number of cylinders on each transport device  18 ,  20  depends on the size of the chamber  34 . The overall dimensions of chamber  34  and the position of the ram  36  therein determine the available volume within the chamber  34 . When a molten polymer is deposited in the transport chamber  34 , the transport device  18 ,  20  is insulated and/or heated. Although not illustrated, necessary electrical, pneumatic and hydraulic components are attached to the transport device  18 ,  20 . 
     Referring now to FIG. 2, the polymer distribution manifold  16  has two outlet ports  30  for providing a continuous discharge of the polymer, with alternating on-off shut off devices  28  located at the outlet ports  30 . When the outside transport chamber  34  is collecting discharging polymer, the mating shut off device  28  is in the open position and the inner shut off device  28  is in the closed position. The shut off devices  28  are reversed when the inside transport chamber  34  is collecting polymer. 
     To allow polymer discharge from the dual outlet manifold  16  into chamber  34  of the transport device  18 ,  20 , a fill port  38  is opened using a toggle lift and rotation clamp  37 . As link  39  is retracted, the toggle clamp  37  lifts the port  38  and rotates it away from the opening  38   a . In the close position, the toggle clamp  37  locks the fill port  38  in place in opening  38   a . To discharge the polymer from the transport chamber  34 , seal  40  is retracted using one or more cylinders  41 , and the ram  36  pushes against the polymer within transport chamber  34 , forcing the polymer out of the exit port  42 . 
     Each movable non-rotatable and hollow transport  18 ,  20  has a top wall  43 , a bottom wall  44  and a pair of ends walls  45 . The entrance port or opening  38   a  is located in the top wall  43 . The exit port or opening  42  is located in the bottom wall  44 . 
     Referring now to FIG. 4, one transport and deposition device  20  that contains molten polymer within the chamber, deposits molten polymer  59  on a planar shaped carrier  60  under the forward movement of a ram which is located within the chamber. An opening is provided in the bottom of the transport device  20  where polymer exits from the chamber. The planar shaped carrier  60  moves under the transport and deposition device  20  as polymer  59  is deposited on the moving carrier  60 . The combined deposited polymer and carrier index forward in a straight line towards a clamping device represented by the platens  13 . Two conveyor side guides  64  with a plurality of clamp attachments  66  hold the carrier  60  during movement via drive roll  62 . The combined deposited polymer  59  and carrier  60  index into a forming device represented by upper and lower platens  13  to which upper and lower mold sections  15  are attached. The forming device close on the combined carrier  60  and the deposited polymer  59  to produce an article of a desired shape. 
     In another aspect of the preferred embodiment, the carrier  60  passes under and collects deposited polymer  59  in both directions from the transport and deposition device  20 . A light-weight core  57  is placed on the first layer of deposited polymer  59  prior to reversing the direction of carrier  60 . Referring now to FIG. 5, the carrier  60  is moved under the transport and deposition device  20  in a direction away from the forming device  13  as polymer  59  is deposited on carrier  60  in a manner described in FIG.  4 . An undercarriage  46  supports the carrier  60  and the deposited polymer  59 , holding the carrier  60  in position with edge clamps  73 . The undercarriage  46  is constructed from a light weight material containing a low friction, heat resistant surface. A multi-axis robot  47  places the rectangular shaped core  57  on the deposited polymer  59  by a rotating fixture  48  attached to the vertical acting robot arm  49 . Core material  57  is collected from a feed station located outside the process area (not shown) by the multi-axis robot rotating fixture  48  using vacuum cups attached to the face of the fixture  48 . Arms  50  and  52  control the horizontal movements of the robot  47 . The fixture  48  releases the core  57  on the deposited polymer  59  and moves away from the combined carrier  60 , deposited polymer  59  and core  57 . The combined materials move back under the transport device  20  and collects deposited polymer from the transport and deposition device  20  in the same manner as described in FIG.  4 . The combined materials continue in a straight-line fashion into the forming device  13  to produce an article of a desired shape out of the combined carrier and polymer encapsulated core material. The undercarriage  46  retracts from the forming device  13  prior to forming a desired shape. 
     Prior to entering the forming device  13 , a surface layer can be laminated to the exposed top layer of deposited polymer  59  at a position between the forming device comprising the platens  13  and the molds  15  and the transport and deposition device  20 . As shown in FIG. 6, the multi-axis movement robot  47  with horizontally moving arms  50  and  52  and a vertically acting arm  49  has an attachment or robot guide  53  capable of rotating around arm  49  from a horizontal to a vertical position. The multi-axis robot  47  picks up a surface material  26  from a feed device such as a magazine (not shown) that is outside the process area. Attachment or robot guide  53  is positioned vertically with a curved lower edge or portion that guides the surface layer  26  as the combined carrier  60  and deposited polymer  59  moves under the robot guide  53 . Undercarriage  46  provides horizontal movement for the combined materials under the curved edge or portion of robot guide  53 . The vertical robot axis  29  applies downward acting force to improve the contact between the surface material  26  and the deposited polymer  59 . Undercarriage  46  provides a counteracting force. A rotary fixture holds the surface material  26  with pneumatically operated side clamps that releases the surface material  26  at the start of the curved edge of attachment or guide  53 . The interface friction between the surface material  26  and moving deposited polymer  59 , together with the compressive force between the undercarriage  46  and attachment or robot guide  53 , combine to move the surface material  26  at the same rate as the deposited polymer  59 . Attachment or guide  53  is positioned between the transport and deposition device  20  and the forming device  13  (not shown). As an alternative to the curved edge or portion of attachment or robot guide  53 , a roller  31  is attached to the curved lower edge of guide  53  as shown in FIG.  7 . The roller  31  would rotate as the combined laminate moves forward. 
     Another method to provide a double layer of deposited polymer  59  on a carrier  60 , two transport and deposition devices  20  are aligned in series so that carrier  60  passes under both transport and deposition devices  20  and accept deposited polymer  59 . An insert  65  is placed between the first and second deposits of polymer  59 . FIG. 8 shows a schematic view of two transport and deposition devices  20  with a carrier  60  passing under the outer or left device  20 . Polymer  59  is deposited on carrier  60  as the carrier moves towards a second transport and deposition device  20  using outboard drives  64  attached to carrier  60  via clamps  66 . An insert  65  is placed on deposited polymer  59  using a multi-axis robot  47  as shown in FIG. 5, prior to passing under the second deposition device  20  where another layer of polymer is deposited prior to indexing into the forming device. The same or different polymers  59  can be deposited from each transport and deposition device  20 . 
     To describe an application that utilizes the combination of a carrier  60 , polymer  59  and an insert  57 , FIG. 9 is a cut-away view of an automotive fascia and bumper combination where carrier  60  becomes a decorative outer surface. Deposited polymer  59  adheres to the carrier  60  and provides structure. A core material  57  is encapsulated by polymer  59  and acts as a beam. A continuous fiber reinforced polymer  59   a  makes up the back support of the composite. The process to produce continuous fiber reinforced, melt deposits is referenced in my copending U.S. patent application, Ser. No. 09/388,052, now U.S. Pat. No. 6,264,462. 
     In reference to a forming device represented by the platens  13 , the preferred embodiment is shown in FIG.  10 . The front view of the forming device consists of upper and lower platens  13  and forming molds  15  attached to the vertical supports  14 . The upper portion of the forming device moves up and down on guides  17  under the forces applied by an actuator  25 . The carrier  60  and deposited polymer  59  are positioned between mold sections  15 . The downward action of the forming device forces the mold sections  15  to close over the combined carrier  60  and deposited polymer  59  to produce an article with the desired shape. 
     In another embodiment, the carrier  60  side of a composite is formed over the core or convex side of a mold half  15 . The preferred carrier  60  is a fluoropolymer composition that has been treated to modify the surface of one side to improve adhesion to the deposited polymer  59 . Two of the finished articles or parts, with or without the same shape, would have edges that align with each other that are fused together to form a closed container  120 . FIGS. 11-13 shows the steps used to produce a sealed container  120 . FIG. 11 is a cross-sectional view of holding fixtures  109  used to position two mating, concave shaped finished articles or parts that face each other with the carrier film  60  on the inside of the concave shape and the solidified deposited polymer  59  on the outside. The carrier sides  60  extend to matching flanges  112  where external infrared heat  105  is selectively applied to the flange areas to soften the carriers. Once the material has softened and can flow under pressure, the two mating edges of the carriers  60  are fused together under the pressure of actuators  107 . The heat source  105  is separated from the holding fixture  109  prior to part fusion. FIG. 12 is a cross-section of the fused container  120  showing fused flanged edges. FIG. 13 is a cut-away view of the sealed container  120 . 
     In reference to an undercarriage  46 , FIG. 14 shows the undercarriage  46  positioned between the upper and lower half&#39;s of the mold  15  within a clamping or forming device  13 . The upper mold half  15   a  is the core or convex side and the lower hold half  15   b  is the cavity or concave side. The carrier  60  has a layer of deposited polymer  59  on the top surface. The carrier  60  is held in place on the undercarriage  46  by a series of vacuum ports  71 . The undercarriage  46  is supported and moves on guides  51  positioned on each side of the lower platen  13 . An extender section  21  connects the undercarriage  46  with the guides  51  to allow the guides  51  to be positioned outside of the mold  15 . On opposite sides of the forming device  13 , pneumatic actuated grips are part of an actuator  19  that can move above the extended section  21  to grip the edges of the carrier  60  on two sides. The actuator  19  lifts the carrier  60  and deposited polymer  59  off the undercarriage  46  until the undercarriage  46  retracts from the forming press  13  after breaking the vacuum hold. The actuators  19  can lower the carrier  60  and keep the carrier  60  in tension until the closing mold half s pull the carrier  60  out of the end grips  11 . 
     FIG. 15 shows a typical cross-section of a part that incorporates features described in this invention. A honeycomb structure  57  is encapsulated on both sides by deposited polymer  59 . A surface material  55  adheres to the lower deposited polymer  59 . Specific desirable properties can be incorporated in the composite by modifying any of the components. 
     The polymer transfer and deposition device of FIG. 16 shows the transport device  20  aligned with the top of a polymer collection device  72 . As the transport device  20  moves forward to combine with the collection device  72 , a hinge  78  is pushed to open a space or chamber  70  where polymer, located in chamber  34 , can be deposited into the collection chamber  72  at a controlled rate. A roll or spool of fiber  76  unwinds and moves through an opening  81  located near or on top of the polymer collection device  72 . 
     The set of drivers  80  pull the fibers  76  into the chamber  70  at a controlled rate. The drivers  80  can move the fiber  76  in a continuous or discontinuous manner. A set of rotating impellers  83  apply inward acting force to the polymer and fibers or fiber mix. Baffles  77  are laterally spaced apart from impellers  83 . Once the polymer transport device  20  has delivered a set amount of polymer, it retracts, allowing hinge  78  to close, and returns the transport device to the plasticating machine  10  where more polymer can be deposited into chamber  34 . The exit position  75  of the polymer coated fiber is adjustable to control the ratio of polymer to fiber. The exit position  75  opening is controlled by seal  40  attached to one or more pistons  41 . Seal  40  has a blade edge that can cut the existing polymer composite to any desired length. The existing polymer composite can be deposited on carrier  60  and moved into a clamping station. Cutters  85  chop fibers to any desirable length. The collection device  72  can be moved on a track system that is similar to the method used to guide the transport devices  18 ,  20  to the various clamp stations  12  and  14 . 
     This invention described above may be modified or have changes made to it within the scope of the invention as defined by the attached claims.