Thermoplastic molding process and apparatus

• US 8,192,664 B2
• Filed: 05/31/2005
• Issued: 06/05/2012
• 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.
• Primary Examiner(s): Lazorcik, Jason L.
• Application Number:
  US11/140,727
• Publication Number:
  US 20060008967A1
• Time in Patent Office: 2,562 Days
• Field of Search: 264/165, 264/176.1, 264/177.17, 264/297.7, 264/211.14, 264/241, 264/211.21, 264/173.11, 264/1.29, 264/13, 264/210.1, 425/449, 425/296, 425/297, 425/376.1
• US Class Current: 264/210.1
• 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 a solid article from a viscous material and fiber, said method comprising:

blending the viscous material with the fiber to form a composite material;

extruding the composite material and depositing gravitationally said composite material onto a lower mold portion;

moving at least a portion of the lower mold portion during gravitational depositing of the composite material, so as to deposit a quantity of composite material on said lower mold portion conforming to mold cavities of the lower mold portion;

compressing an upper mold portion against said quantity of composite material, after said quantity of composite material has been gravitationally deposited onto said lower mold portion; and

maintaining the quantity of composite material under such conditions that the quantity of composite material hardens within a mold cavity formed between the upper mold portion and the lower mold portion, so as to form said solid article.

2. The method of claim 1, further comprising controlling flow of composite material to vary the quantity of composite material being gravitationally deposited onto the lower mold portion over time.

3. The method of claim 1, wherein the fiber blended with the viscous material is between approximately one-half and approximately four inches in length.

4. The method of claim 1, wherein the fiber has an average fiber length of at least one inch.

5. The method of claim 1, wherein said composite material comprises a concentration of fiber of approximately at least ten percent by weight.

6. The method of claim 1, wherein the composite material comprises a concentration of fiber of at least 40 percent by weight.

7. The method of claim 1, wherein moving of the lower mold portion, results in formation of a predetermined quantity of composite material of varying thickness on said lower mold portion.

8. The method of claim 1, wherein moving of the lower mold portion is along a single axis.

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

10. The method of claim 1, further comprising the step of controlling said extruding to vary a volumetric flow rate and a relative position of an extrusion die and the lower mold portion.

11. The method of claim 1, wherein the composite material is extruded onto an insert contained within the lower mold portion.

12. The method of claim 11, wherein the insert is at least partially embedded within the composite material.

13. The method of claim 1, wherein, extruding comprises extruding at least one first layer and at least one second layer onto the lower mold portion.

14. The method of claim 1, wherein said viscous material comprises a thermoplastic resin.

15. The method of claim 1, wherein said viscous material comprises a thermoset resin.

16. The method of claim 1, wherein said maintaining step comprises causing a chemical reaction within the mold cavity.

17. The method of claim 1, wherein the viscous material comprises at least one polymer selected from the group consisting of:

polyethylene;

polysulfone;

polypropylene oxide;

polyvinyl chloride;

polybutylene terephthalate;

polyvinylidene chloride;

polyethylene terephthalate;

polystyrene;

polycyclohexane diethylene;

terephthalate;

styrene-butadiene-acrylonitrile;

polybutylene naphthalate copolymer;

nylon 6;

nylon 66;

nylon 11;

nylon 12;

thermotropic liquid crystal polymers;

polyphenylene sulfide;

polyether ether ketones;

polyether sulfones;

copolymers of aliphatic nylons polyether imides further copolymerized with terephthalic acid or other aromatic dicarboxylic acids or aromatic diamines;

polyamide imides;

copolymerized polyamides polyimides;

polycarbonate;

polyurethane;

polyacetal;

polyether amides;

polymethylmethacrylate; and

polyester amides.

18. The method of claim 1, wherein extruding comprises dynamically outputting the composite material at different volumetric flow rates across a plane;

and

positionally synchronizing said lower mold portion to receive the composite material in relation to the different volumetric flow rates across the plane.

19. The method of claim 1 wherein said lower mold portion resides on a trolley, and said upper mold portion resides within a press, said method further comprising,

transporting said lower mold portion on said trolley into said press, after depositing gravitationally said composite material onto said lower mold portion, and

compressing, within said press, said upper mold portion against said quantity of composite material, after said quantity of composite material has been gravitationally deposited onto said lower mold portion.