Thermoplastic molding process and apparatus

• US 20060008967A1
• Filed: 05/31/2005
• Published: 01/12/2006
• Est. Priority Date: 12/18/1997
• Status: Active Grant

• Current Assignee: D & D Manufacturing, LLC
• Original Assignee: Lrm Industries International Inc.
• Inventors: Polk, Dale E. Jr., Polk, Dale E. Sr.
• Granted Patent: US 8,192,664 B2
• Time in Patent Office: Days
• US Class Current: 438/202
• CPC Class Codes: B29C 2043/046 travelling between different stations, e.g. feeding, moulding, curing stations
• CPC Class Codes: B29C 2043/3433 using dispensing heads, e.g. extruders, placed over or apart from the moulds
• CPC Class Codes: B29C 2043/3444 using pressurising feeding means located in the mould, e.g. plungers or pistons
• CPC Class Codes: B29C 2043/3488 uniformly distributed into the mould
• CPC Class Codes: B29C 2948/92019 Pressure
• CPC Class Codes: B29C 2948/92076 Position, e.g. linear or angular
• CPC Class Codes: B29C 2948/92085 Velocity
• CPC Class Codes: B29C 2948/9218 Weight
• CPC Class Codes: B29C 2948/92209 Temperature
• CPC Class Codes: B29C 2948/92542 Energy, power, electric current or voltage
• CPC Class Codes: B29C 2948/92571 Position, e.g. linear or angular
• CPC Class Codes: B29C 2948/9258 Velocity
• CPC Class Codes: B29C 2948/926 Flow or feed rate
• CPC Class Codes: B29C 2948/92647 Thickness
• CPC Class Codes: B29C 2948/92657 Volume or quantity
• CPC Class Codes: B29C 2948/92704 Temperature
• CPC Class Codes: B29C 2948/92885 Screw or gear
• CPC Class Codes: B29C 2948/92904 Die; Nozzle zone
• CPC Class Codes: B29C 2948/92933 Conveying, transporting or storage of articles
• CPC Class Codes: B29C 2948/92952 Drive section, e.g. gearbox, motor or drive fluids
• CPC Class Codes: B29C 2948/92961 : Auxiliary unit, e.g. for external melt filtering, re-combining or transfer between units
• CPC Class Codes: B29C 31/047 : combined with moving moulds B29C31/044, B29C31/048 take precedence
• CPC Class Codes: B29C 31/048 : the material being severed at the dispensing head exit, e.g. as ring, drop or gob, and transported immediately into the mould, e.g. by gravity
• CPC Class Codes: B29C 33/34 : movable, e.g. to or from the moulding station
• CPC Class Codes: B29C 43/021 : characterised by the shape of the surface
• CPC Class Codes: B29C 43/04 : using movable moulds
• CPC Class Codes: B29C 43/34 : Feeding the material to the mould or the compression means B29C43/085 takes precedence
• CPC Class Codes: B29C 48/001 : Combinations of extrusion moulding with other shaping operations
• CPC Class Codes: B29C 48/0011 : combined with compression moulding
• CPC Class Codes: B29C 48/0017 : combined with blow-moulding or thermoforming
• CPC Class Codes: B29C 48/0018 : combined with shaping by orienting, stretching or shrinking, e.g. film blowing B29C48/0017 takes precedence
• CPC Class Codes: B29C 48/0022 : combined with cutting
• CPC Class Codes: B29C 48/05 : Filamentary, e.g. strands
• CPC Class Codes: B29C 48/07 : Flat, e.g. panels
• CPC Class Codes: B29C 48/12 : Articles with an irregular circumference when viewed in cross-section, e.g. window profiles
• CPC Class Codes: B29C 48/2556 : provided in or in the proximity of dies B29C48/302, B29C48/31, B29C48/325 take precedence
• CPC Class Codes: B29C 48/285 : Feeding the extrusion material to the extruder
• CPC Class Codes: B29C 48/2886 : of fibrous, filamentary or filling materials, e.g. thin fibrous reinforcements or fillers
• CPC Class Codes: B29C 48/297 : at several locations, e.g. using several hoppers or using a separate additive feeding
• CPC Class Codes: B29C 48/31 : being adjustable , i.e. having adjustable exit sections
• CPC Class Codes: B29C 48/92 : Measuring, controlling or regulating
• CPC Class Codes: B29C 70/46 : using matched moulds, e.g. for deforming sheet moulding compounds [SMC] or prepregs
• CPC Class Codes: B29K 2105/06 : containing reinforcements, fillers or inserts
• CPC Class Codes: B29K 2105/12 : of short lengths, e.g. chopped filaments, staple fibres or bristles
• CPC Class Codes: B29L 2007/002 : Panels; Plates; Sheets
• CPC Class Codes: B29L 2031/7178 : Pallets
• CPC Class Codes: B29L 2031/732 : Floor coverings piles carpets B29L2031/7652; for vehicles B29L2031/3017
• CPC Class Codes: Y10T 428/24124 : Fibers
• CPC Class Codes: Y10T 428/2457 : Parallel ribs and/or grooves
• CPC Class Codes: Y10T 428/249924 : Noninterengaged fiber-containing paper-free web or sheet which is not of specified porosity

Abstract

A system and method for forming an article from thermoplastic material and fiber. The method includes heating thermoplastic material to form a molten thermoplastic material for blending with the fiber. The molten thermoplastic material is blended with the fibers to form a molten composite material having a concentration of fiber by weight. The molten composite material may then be extruded through dynamic dies to deliver discrete controlled material that is gravitated onto a lower portion of a mold. The lower portion of the mold may be moved in space and time while receiving the flow of composite material to deposit a predetermined quantity of molten composite material thereon conforming to mold cavities of the lower and an upper portion of the mold. The upper portion of the mold may be pressed against the predetermined quantity of molten composite material and closing on the lower portion of the mold to form the article.

Claims

1. A method for forming an article from thermoplastic material and fiber, said method comprising:

heating thermoplastic material to form a molten thermoplastic material for blending with the fiber;

blending the molten thermoplastic material with the fibers to form a molten composite material having a concentration of fiber by weight;

extruding the molten composite material to form a flow of composite material gravitating onto a lower portion of a mold for forming the article;

moving the lower portion of the mold in space and time while receiving the flow of composite material to deposit a predetermined quantity of molten composite material thereon conforming to mold cavities of the lower and an upper portion of the mold; and

pressing the upper portion of the mold against the predetermined quantity of molten composite material and closing on the lower portion of the mold to form the article.

2. The method according to claim 1, further comprising controlling the flow of composite material to vary the quantity of molten composite material being delivered to the lower portion of the mold.

3. The method according to claim 1, wherein said blending includes blending the molten thermoplastic material with the fibers being between approximately at least one-half and approximately four inches in length.

4. The method according to claim 1, wherein said blending forms a molten composite material having a concentration of fiber of approximately at least ten percent by weight.

5. The method according to claim 1, wherein said moving of the lower portion of the mold forms a predetermined quantity of molten composite material of varying thickness on the mold.

6. The method according to claim 1, wherein said moving of the lower portion of the mold is along a single axis.

7. The method according to claim 1, wherein said extruding produces a molten composite material having a minimum of approximately 85 percent of unbroken fibers.

8. The method according to claim 1, wherein the gravitating flows the composite material with a volumetric flow rate substantially the same onto the lower portion of the mold.

9. The method according to claim 1, wherein the gravitating flows the composite material with different volumetric flow rates onto the lower portion of the mold.

10. The method according to claim 1, further comprising controlling said extruding to vary the volumetric flow rate of the molten composite material being gravitated onto the lower portion of the mold.

11. The method according to claim 1, wherein the gravitating of the molten composite material is performed directly onto the lower portion of the mold.

12. The method according to claim 1, wherein the molten composite material is extruded on to an insert contained within the lower portion of the mold.

13. The method according to claim 12, wherein the insert is partially embedded within the thermoplastic material.

14. The method according to claim 12, wherein the insert is completely embedded within the thermoplastic material.

15. The method according to claim 12, wherein the insert is encapsulated with thermoplastic composite material.

16. The method according to claim 1, wherein a first layer of thermoplastic composite material is extruded into the lower portion of the mold.

17. The method according to claim 16, wherein a second layer of thermoplastic material is layered on top of the first layer.

18. The method according to claim 16, wherein an insert is placed on the first layer.

19. The method according to claim 18, wherein said insert is partially embedded within the first layer.

20. The method according to claim 18, wherein said insert is completely embedded within the first layer.

21. The method according to claim 18, wherein a second layer of thermoplastic material is layered on top of the insert.

22. A system for forming an article from thermoplastic material and fiber, said system comprising:

a heater operable to pre-heat reinforced thermoplastic material to form a molten thermoplastic material;

an extruder coupled to the heater and operable to melt and blend the molten thermoplastic material with the fiber to form a flow of composite material for gravitating onto a lower portion of a mold to form the article;

a movable structure coupled to the lower portion of the mold and operable to be moved in space and time while receiving the flow of composite material to deposit a predetermined quantity of molten composite material thereon conforming to mold cavities of the lower and an upper portion of the mold; and

a press coupled to the upper portion of the mold and capable of receiving said movable structure with the lower portion of the mold, said press operable to press the upper portion of the mold against the predetermined quantity of molten composite material on the lower portion of the mold to form the article.

23. The system according to claim 22, further comprising a dynamic die having at least one flow control element and operable to control the flow of composite material in a varied amount of molten composite material being delivered to the lower portion of the mold.

24. The system according to claim 22, wherein said extruder includes an auger having a thread spacing large enough to blend the molten thermoplastic material with the fibers being between approximately one and approximately four inches in length.

25. The system according to claim 22, wherein the blended molten composite material has a concentration of fiber of at least approximately ten percent by weight.

26. The system according to claim 22, further comprising a controller coupled to said moveable structure and operable to move of said moveable structure to position the lower portion of the mold to form a predetermined quantity of molten composite material of varying thickness on the mold.

27. The system according to claim 22, wherein said moveable structure includes wheels operable to move the moveable structure.

28. The system according to claim 22, wherein said extruder includes an auger operable to produce a molten composite material having a minimum of approximately 85 percent of unbroken fibers.

29. The system according to claim 22, further comprising a die coupled to said extruder and operable to gravitate the flow of the composite material with a volumetric flow rate substantially the same across a plane onto the lower portion of the mold.

30. The system according to claim 22, further comprising a dynamic die coupled to said extruder and operable to gravitate the composite material with different volumetric flow rates across a plane onto the lower portion of the mold.

31. The system according to claim 22, further comprising a controller coupled to said extruder and operable to vary the volumetric flow rate of the molten composite material from the extruder and gravitate the molten composite material onto the lower portion of the mold.

32. The system according to claim 31, wherein said controller moves said movable structure directly below said extruder for gravitating the extruded composite material onto the lower portion of the mold.

33. A system for forming an article from thermoplastic material and fiber, said system comprising:

means for heating thermoplastic material to form a molten thermoplastic material for blending with the fiber;

means for blending the molten thermoplastic material with the fibers to form a molten composite material having a concentration of fiber by weight;

means for extruding the molten composite material to form a flow of composite material gravitating onto a lower portion of a mold for forming the article;

means for moving the lower portion of the mold in space and time while receiving the flow of composite material to deposit a predetermined quantity of molten composite material thereon conforming to mold cavities of the lower and an upper portion of the mold; and

means for pressing the upper portion of the mold against the predetermined quantity of molten composite material and closing on the lower portion of the mold to form the article.

34. The system according to claim 33, further comprising means for controlling the flow of composite material to vary the quantity of molten composite material being delivered to the lower portion of the mold.

35. The system according to claim 33, further comprising means for controlling said means for extruding to vary the volumetric flow rate of the molten composite material being gravitated onto the lower portion of the mold.

36. An article formed of an extruded composite material comprising a thermoplastic material and having a concentration of at least 10 percent by weight of fiber having lengths of at least one-half inch.

37. The article according to claim 36, further comprising hidden ribs.

38. The article according to claim 36, wherein the article is a single composite material having structural features of different depths.

39. The article according to claim 38, wherein the different depths of the structural features are greater than approximately one inch.

40. The article according to claim 36, wherein the concentration of weight of fiber for the composite material is at least 30 percent.

41. The article according to claim 36, wherein the length of fiber is at least approximately three inches.

42. An article formed of an extruded composite material comprising a thermoplastic material blended with fibers, the article having hidden ribs.

43. The article according to claim 42, wherein the fibers have lengths of at least three inches long.

44. The article according to claim 42, wherein the concentration of fibers is at least approximately 10 percent.

45. The article according to claim 42, wherein the concentration of fibers is at least approximately 40 percent.

49. The article according to claim 42, wherein the concentration of fibers is at least approximately 40 percent.

46. An article formed of an extruded composite material comprising a thermoplastic material blended with fibers, the article having structural features including different draft depths.

47. The article according to claim 46, wherein the fibers have lengths of at least approximately three inches long.

48. The article according to claim 46, wherein the concentration of fibers is at least approximately 10 percent.

50. An article formed of an extruded composite material comprising a thermoplastic material blended with fibers having at least a portion of an element encapsulated in the extruded composite material.

51. The article according to claim 50, wherein the entire element is encapsulated in the extruded composite material.

52. The article according to claim 50, wherein the fibers have lengths of at least approximately three inches long.

53. The article according to claim 50, wherein the concentration of fibers is at least approximately 10 percent.

54. The article according to claim 50, wherein the concentration of fibers is at least approximately 40 percent.

55. The article according to claim 50, wherein the element is a fastener.

56. The article according to claim 50, wherein the element is a stiffener.

57. The article according to claim 50, wherein the element is an attachment.

58. The article according to claim 50, wherein the thermoplastic material comprises one or more layers of thermoplastic composite material.

59. The article of claim 58, wherein the one or more layers of thermoplastic material have the same composition.

60. The article of claim 58, wherein the one or more layers of thermoplastic material have different compositions.

61. A method for forming a thermoplastic structural component, said method comprising:

receiving a thermoplastic material;

heating the thermoplastic material;

receiving fibers having a predetermined fiber length;

blending the fibers with the heated thermoplastic material to form a composite material;

extruding the composite material;

dynamically outputting the extruded composite material at different volumetric flow rates across a plane;

positionally synchronizing a mold to receive the extruded composite material in relation to the different volumetric flow rates across the plane; and

pressing the extruded composite material into the mold to form the thermoplastic structural component.

62. The method according to claim 61, further comprising forming the thermoplastic material from thermoplastic resin.

63. The method according to claim 61, wherein said heating includes melting the thermoplastic material.

64. The method according to claim 61, further comprising selecting the fiber length of at least one inch.

65. The method according to claim 61, wherein said outputting of the different volumetric flow rates ranges between approximately zero and 3000 pounds per hour.

66. The method according to claim 65, wherein said flow rate ranges between approximately 2500 and 3000 pounds per hour.

67. The method according to claim 61, wherein said positionally synchronizing includes translating the mold with respect to the volumetric rates.

68. The method according to claim 61, further comprising predetermining the different volumetric flow rates based on cavity volume of the mold across the plane.

69. The method according to claim 61, wherein the forming of thermoplastic structural component includes forming a pallet.

70. The method according to claim 61, further comprising configuring an element in the mold to be encapsulated by the composite material.

71. The method according to claim 61, wherein said dynamic outputting of the extruded composite material is performed by controlling discrete flow control elements.

72. The method according to claim 61, wherein said mixing produces a composite material having at least approximately 10 percent concentration of fiber by weight.

73. The method according to claim 61, wherein said mixing produces a composite material having at least approximately 40 percent concentration of fiber by weight.

88. The system according to claim 72, wherein the dynamic element is a screw having a thread spacing larger than the maximum length of the stiffening material.

89. The system according to claim 72, wherein said mobile unit has revolving elements coupled thereto.

90. The system according to claim 89, wherein said mobile unit includes at least one dynamic positioning element operable to engage and disengage the revolving elements.

91. The system according to claim 90, wherein said controller is operable to disengage the revolving elements while said mobile unit is positioned in said press for the extruded composite material to be pressed into the mold.

74. A system for forming a thermoplastic structural component, said system comprising:

means for receiving a thermoplastic material;

means for heating the thermoplastic material;

means for receiving fibers having a predetermined fiber length;

means for mixing the heated thermoplastic material with the fibers to form a composite material;

means for extruding the composite material;

means for dynamically outputting the extruded composite material at different volumetric flow rates across a plane;

means for positionally synchronizing a mold to receive the extruded composite material in relation to the different volumetric flow rates across the plane; and

means for pressing the extruded composite material into the mold to form the thermoplastic structural component.

75. The system according to claim 74, further comprising means for forming the thermoplastic material from thermoplastic resin.

76. The system according to claim 74, wherein said means for heating includes means for melting the thermoplastic material.

77. The system according to claim 74, wherein said means for positionally synchronizing includes means for translating the mold with respect to the volumetric rates.

78. The system according to claim 74, further comprising means for predetermining the different volumetric flow rates based on cavity volume of the mold across the plane.

79. The system according to claim 74, further comprising means for setting a non-thermoplastic element in the mold to be encapsulated by the composite material.

80. The system according to claim 74, wherein said means for mixing produces a composite material having at least approximately 10 percent concentration of fiber.

81. The system according to claim 74, wherein said means for mixing produces a composite material having at least approximately 40 percent concentration of fiber.

82. A system for forming a thermoplastic structural component, said system comprising:

a material receiving unit operable to receive a thermoplastic material and stiffening material;

a heater unit operable to heat the thermoplastic material;

an extruder coupled to the material receiving unit and operable to extrude the composite material;

a dynamic die having a plurality of selectably alterable flow control elements operable to control output of the composite material;

a mobile unit operable to support a mold and to be dynamically positioned below the dynamic die;

a controller electrically coupled to said dynamic die and mobile unit, said controller operable to dynamically alter said flow control elements to output the extruded composite material at different volumetric flow rates across a plane and position said mobile unit in synchronicity with the altering of said flow control elements to apply the extruded composite material onto the mold; and

a press operable to receive said mobile unit and press the extruded composite material into the mold.

83. The system according to claim 82, wherein said material receiving unit includes at least one feeder.

84. The system according to claim 82, wherein said heater unit is further operable to heat the thermoplastic material to a melted thermoplastic state.

85. The system according to claim 82, wherein said extruder includes a dynamic element operable to substantially avoid damaging the stiffening material.

86. The system according to claim 85, wherein the stiffening material is formed of fibers having a predetermined maximum length of approximately one inch.

87. The system according to claim 85, wherein the stiffening material is formed of fibers having a predetermined maximum length of approximately three inches.

92. The system according to claim 82, wherein the composite material is formed having a concentration of approximately 10 percent by weight of stiffening material.

93. A method for forming a structural part from thermoplastic material and fiber, said method comprising:

positioning an insert in a mold;

depositing molten extruded composite material on the mold;

forming extruded composite material about at least a portion of the insert;

removing supports, if any, used to configure the insert in the mold;

compressing the extruded composite material to form the structural part; and

removing the structural part with the insert at least partially embedded from the mold.

94. The method according to claim 93, wherein said positioning of the insert is performed in a lower portion of the mold.

95. The method according to claim 93, wherein said depositing the molten extruded composite material is performed dynamically across a plane.

96. The method according to claim 93, wherein said forming the extruded composite material includes encapsulating the entire insert within the extruded composite material.

97. The method according to claim 93, further comprising pressing the extruded composite material in the mold.

98. A system for forming a structural part from thermoplastic material and fiber, said system comprising:

means for configuring an insert in a mold;

means for depositing molten extruded composite material on the mold;

means for forming extruded composite material about at least a portion of the insert;

means for removing supports, if any, used to configure the insert in the mold;

means for compressing the extruded composite material to form the structural part; and

means for removing the structural part with the insert at least partially embedded from the mold.

99. The system according to claim 98, wherein said means for configuring of the insert is coupled to a lower portion of the mold.

100. The system according to claim 98, wherein said means for depositing the molten extruded composite material includes means for dynamically flowing the extruded composite material across a plane.

101. The system according to claim 98, wherein said means for forming the extruded composite material includes means for encapsulating the entire insert within the extruded composite material.

102. The system according to claim 98, further comprising means for pressing the extruded composite material in the mold.