Cross-lamination injection molding

• US 5,045,268 A
• Filed: 12/11/1989
• Issued: 09/03/1991
• Est. Priority Date: 12/11/1989
• Status: Expired due to Term

• Current Assignee: Sorensen Research & Development Trust
• Original Assignee: Jens Erik Sorensen
• Inventors: Sorensen, Jens O.
• Primary Examiner(s): HEITBRINK, JILL LYNNE
• Application Number:
  US07/448,763
• Time in Patent Office: 631 Days
• Field of Search: 264/245, 264/246, 264/255, 264/265, 264/294, 264/328.1, 264/328.7, 264/328.8, 264/328.11, 264/328.12, 425/126.1, 425/127, 425/129.1, 425/130, 425/134
• US Class Current: 264/246
• CPC Class Codes: B29C 45/0046 Details relating to the filling pattern or flow paths or flow characteristics of moulding material in the mould cavity
• CPC Class Codes: B29C 45/16 Making multilayered or multicoloured articles B29C45/0062 takes precedence; feeding colouring materials into the injection unit B29C45/1816
• CPC Class Codes: B29C 45/1635 using displaceable mould parts, e.g. retractable partition between adjacent mould cavities

Abstract

A plastic product having a cross-laminated section including a first plastic layer and a second plastic layer is injection molded in a mold system that includes a first mold cavity with a first-layer-defining-mold-cavity-section and a second mold cavity with a second-layer-defining-mold-cavity-section that has a second-cavity-section-wall. The product is molded by injecting a quantity of first plastic into the first mold cavity so that first plastic flows from a flow channel into the first-layer-defining-mold-cavity-section in a first predetermined general direction that is different than the direction of the flow channel; solidifying at least partly the flowed first plastic in the first-layer-defining-mold-cavity-section to thereby form said first plastic layer having a first-direction-flow-record; adjusting the mold system to provide the second mold cavity, with the second-cavity-section-wall including the first plastic layer; injecting a quantity of second plastic into the second mold cavity so that second plastic flows from a flow channel into the second-layer-defining-mold-cavity-section in a second predetermined general direction that is different than the direction of the flow channel, whereby second plastic in the second-layer-defining-mold-cavity-section fuses with the first plastic layer; and solidifying the flowed second plastic in the second-layer-defining-mold-cavity-section to thereby form the second plastic layer, so that the second plastic layer has a second-direction-flow-record, which is positively different from the first-direction-flow-record, to thereby form the plastic product with the cross-laminated section that includes both the first plastic layer and the second plastic layer. The first plastic and the second plastic are injected through at least one shared gate.

Claims

1. A method of injection molding a plastic product, with a cross-laminated section that includes a first plastic layer and a second plastic layer, in a mold system comprising a first mold cavity with a first-layer-defining-mold-cavity-section and a second mold cavity with a second-layer-defining-mold-cavity-section with a second-cavity-section-wall, the method comprising the steps of:

(a) injecting a quantity of first plastic into the first mold cavity so that the first plastic follows in the first-layer-defining-mold-cavity-section in a first predetermined general direction,

(b) solidifying at least partly the flowed first plastic in the first-layer-defining-mold-cavity-section to thereby form said first plastic layer having a first-direction-flow-record,

(c) adjusting the mold system to thereby provide the second mold cavity with the second-cavity-section-wall including said first plastic layer,

(d) injecting a quantity of second plastic into the second mold cavity so that the second plastic flows in the second-layer-defining-mold-cavity-section in a second predetermined general direction, whereby the second plastic in the second-layer-defining-mold-cavity-section fuses with said first plastic layer,

(e) solidifying the flowed second plastic in the second-layer-defining-mold-cavity-section to thereby form said second plastic layer, so that the second plastic layer has a second-direction-flow-record which is positively different from said first-direction-flow-record, to thereby form said plastic product with said cross-laminated section that includes both the first plastic layer and the second plastic layer, and

(f) adjusting the mold system to thereby eject the product,

wherein the first mold cavity comprises a first-cavity-flow-channel which is located adjacent the first-layer-defining-mold-cavity-section, with a flow channel being defined as a portion of a mold cavity which is significantly thicker and wider than the adjacent mold cavity thickness for the purpose of directing the flow of injected plastic, and wherein step (a) comprises the step of;

(g) directing the first plastic into the first-layer-defining-mold-cavity-section via the first-cavity-flow-channel, so that the first plastic flows in the first-cavity-flow-channel in a direction which is positively different from said first predetermined general direction.

2. A method according to claim 1, wherein the second mold cavity comprises a second-cavity-flow-channel which is located adjacent said second-layer-defining-mold-cavity-section, and wherein step (d) comprises the step of:

(h) directing second plastic into the second-layer-defining-mold-cavity-section via the second-cavity-flow-channel, so that the second plastic flows in the second-cavity-flow-channel in a direction which is positively different from said second predetermined general direction.

3. A method according to claim 2, wherein the second-layer-defining-mold-cavity-section is at least as thick as said first-cavity-flow-channel, and wherein the first-layer-defining-mold-cavity-section is at least as thick as said second-cavity-flow-channel.

4. A method according to claim 1, wherein the cross-laminated section of the plastic product includes a primary plastic layer, and the mold system includes a primary mold cavity with a primary-layer-defining-mold-cavity-section, and the first-layer-defining-mold-cavity-section has a first-cavity-section-wall, and prior to beginning step (a) the method comprises the steps of:

(h) injecting a quantity of primary plastic into the primary mold cavity so that the primary plastic flows in the primary-layer-defining-mold-cavity-section in a primary predetermined general direction,

(i) solidifying at least partly the flowed primary plastic in the primary-layer-defining-mold-cavity-section to thereby form said primary plastic layer having a primary-direction-flow-record,

(j) adjusting the mold system to thereby provide the first mold cavity with the first-cavity-section-wall including said first plastic layer,

wherein step (a) comprises the step of;

(k) fusing the first plastic in the first-layer-defining-mold cavity-section with said primary plastic layer,

wherein step (b) comprises the step of;

(l) solidifying at least partly the flowed first plastic in the first-layer-defining-mold-cavity-section, so that the first plastic layer has a first-direction-flow-record which is positively different from said primary-direction-flow-record.

5. A method according to claim 1, wherein said second plastic layer is molded with a second-direction-flow-record which is approximately at a right angle to said first-direction-flow-record.

6. A method according to claim 5, wherein said second plastic layer is molded with a wall thickness which is approximately the same as the wall thickness of the first plastic layer.

7. A method according to claim 5, wherein said second plastic layer is molded with a wall thickness which is much thicker than said first plastic layer.

8. A method according to claim 1, wherein said second plastic layer is molded with a wall thickness which is approximately the same as the wall thickness of the first plastic layer.

9. A method according to claim 1, wherein said second plastic layer is molded with a wall thickness which is much thicker than said first plastic layer.

10. A method according to claim 9, wherein said second plastic layer is molded with a second-direction-flow-record which is approximately at a right angle to said first-direction-flow-record.

11. A method according to claim 1, wherein the first plastic and the second plastic are injected through at least one shared gate means.

12. A method according to claim 1, wherein the first plastic and the second plastic are injected through separate gate means.

13. A method according to claim 1, wherein the first mold cavity comprises a retractable wall section and becomes the second mold cavity subsequent to the retractable wall section being retracted and subsequent to the second-cavity-section-wall becoming inclusive of said first plastic layer, wherein step (c) comprises the step of:

(h) adjusting the mold system by retracting the retractable wall section, so that the second mold cavity retains said first plastic layer.

14. A method according to claim 1, wherein the mold system includes a first mold with a first gate part and a complementary part and the mold system further includes a second mold with a second gate part and the same complementary part, wherein step (c) comprises the step of:

(h) adjusting the mold system by separating the first gate part from the complementary part and combining the second gate part with the complementary part while retaining the first plastic layer with the complementary part, thereby transferring the first plastic layer from the first mold to the second mold in order to compose said second mold cavity subsequent to the second-cavity-section-wall including said first plastic layer.

15. A method according to claim 1, wherein the mold system includes a first mold with a first mold cavity and a separate second mold with a second mold cavity, wherein step (c) comprises the step of:

(h) transferring the first plastic layer from the first mold to the second mold in order to compose said second mold cavity subsequent to the second-cavity-section-wall including said first plastic layer

16. A method according to claim 1, wherein step (c) includes the step of:

(h) adding a substance to the surface of the first plastic layer, before step (d) wherein the first plastic layer fuses with the second plastic layer, in order to seal the substance between the first plastic layer and the second plastic layer.

17. A method according to claim 1, wherein the first plastic is the same material and the same color or transparency as the second plastic.

18. A method according to claim 1, wherein the first plastic is the same material as the second plastic but the first plastic has a different color or transparency than the second material.

19. A method according to claim 1, wherein the first plastic is a material which has a different chemical composition than the second plastic.

20. A method according to claim 1, wherein the second-layer-defining-mold-cavity-section is at least as thick as said first-cavity-flow-channel.

21. A method of injection molding a plastic product, with a cross-laminated section that includes a first plastic layer and a second plastic layer, in a mold system comprising a first mold cavity with a first-layer-defining-mold-cavity-section and a second mold cavity with a second-layer-defining-mold-cavity-section with a second-cavity-section-wall, the method comprising the steps of:

(a) injecting a quantity of first plastic into the first mold cavity so that the first plastic flows in the first-layer-defining-mold-cavity-section in a first predetermined general direction,

(b) solidifying at least partly the flowed first plastic in the first-layer-defining-mold-cavity-section to thereby form said first plastic layer having a first-direction-flow-record,

(c) adjusting the mold system to thereby provide the second mold cavity with the second-cavity-section-wall including said first plastic layer,

(d) injecting a quantity of second plastic into the second mold cavity so that the second plastic flows in the second-layer-defining-mold-cavity-section in a second predetermined general direction, whereby the second plastic in the second-layer-defining-mold-cavity-section fuses with said first plastic layer

(e) solidifying the flowed second plastic in the second-layer-defining-mold-cavity-section to thereby form said second plastic layer, so that the second plastic layer has a second=direction-flow-record which is positively different from said first-direction-flow-record, to thereby form said plastic product with said cross-laminated section that includes both the first plastic layer and the second plastic layer, and

(f) adjusting the mold system to thereby eject the product,

wherein the second mold cavity comprises a second-cavity-flow-channel which is located adjacent said second-layer-defining-mold-cavity-section, with a flow channel being defined as a portion of a mold cavity which is significantly thicker and wider than the adjacent mold cavity thickness for the purpose of directing the flow of injected plastic, and wherein step (d) comprises the step of;

(g) directing second plastic into the second-layer-defining-mold-cavity-section via the second-cavity-flow-channel, so that the second plastic flows in the second-cavity-flow-channel in a direction which is positively different from said second predetermined general direction.

22. A method according to claim 21, wherein the cross-laminated section of the plastic product includes a primary plastic layer, and the mold system includes a primary mold cavity with a primary-;

layer-defining-mold-cavity-section, and the first-layer-defining-mold-cavity-section has a first-cavity-section-wall, and prior to beginning step (a) the method comprises the steps of;

(h) injecting a quantity of primary plastic into the primary mold cavity so that the primary plastic flows in the primary-layer-defining-mold-cavity-section in a primary predetermined general direction,

(i) solidifying at least partly the flowed primary plastic in the primary-layer-defining-mold-cavity-section to thereby form said primary plastic layer having a primary-direction-flow-record,

(j) adjusting the mold system to thereby provide the first mold cavity with the first-cavity-section-wall including said first plastic layer,

wherein step (a) comprises the step of;

(k) fusing the first plastic in the first-layer-defining-mold-cavity-section with said primary plastic layer,

wherein step (b) comprises the step of;

(l) solidifying at least partly the flowed first plastic in the first-layer-defining-mold-cavity-section, so that the first plastic layer has a first-direction-flow-record which is positively different from said primary-direction-flow-record.

23. A method according to claim 21, wherein said second plastic layer is molded with a second-direction-flow-record which is approximately at a right angle to said first-direction-flow-record.

24. A method according to claim 23, wherein said second plastic layer is molded with a wall thickness which is approximately the same as the wall thickness of the first plastic layer.

25. A method according to claim 23, wherein said second plastic layer is molded with a wall thickness which is much thicker than said first plastic layer.

26. A method according to claim 21, wherein said second plastic layer is molded with a wall thickness which is approximately the same as the wall thickness of the first plastic layer.

27. A method according to claim 21, wherein said second plastic layer is molded with a wall thickness which is much thicker than said first plastic layer.

28. A method according to claim 27, wherein said second plastic layer is molded with a second-direction-flow-record which is approximately at a right angle to said first-direction-flow-record.

29. A method according to claim 21, wherein the first plastic and the second plastic are injected through at least one shared gate.

30. A method according to claim 21, wherein the first plastic and the second plastic are injected through separate gate means.

31. A method according to claim 21, wherein the first mold cavity comprises a retractable wall section and becomes the second mold cavity subsequent to the retractable wall section being retracted and subsequent to the second-cavity-section-wall becoming inclusive of said first plastic layer, wherein step (c) comprises the step of:

(h) adjusting the mold system by retracting the retractable wall section, to the second mold cavity retains said first plastic layer.

32. A method according to claim 21, wherein the mold system includes a first mold with a first gate part and a complementary part and the mold system further includes a second mold with a second gate part and the same complementary part, wherein step (c) comprises the step of:

(h) adjusting the mold system by separating the first gate part from the complementary part and combining the second gate part with the complementary part while retaining the first plastic layer with the complementary part, thereby transferring the first plastic layer from the first mold to the second mold in order to compose said second mold cavity subsequent to the second-cavity-section-wall including said first plastic layer.

33. A method according to claim 21, wherein the mold system includes a first mold with a first mold cavity and a separate second mold with a second mold cavity, wherein step (c) comprises the step of:

(h) transferring the first plastic layer form the first mold to the second mold in order to compose said second mold cavity subsequent to the second-cavity-section-wall including said first plastic layer.

34. A method according to claim 21, wherein step (c) includes the step of:

(h) adding a substance to the surface of the first plastic layer, before step (d) wherein the first plastic layer fuses with the second plastic layer, in order to seal the substance between the first plastic layer and the second plastic layer.

35. A method according to claim 21, wherein the first plastic is the same material and the same color or transparency as the second plastic.

36. A method according to claim 21, wherein the first plastic is the same material as the second plastic but the first plastic has a different color or transparency than the second material.

37. A method according to claim 21, wherein the first plastic is a material which has a different chemical composition than the second plastic.

38. A method according to claim 21, wherein the first-layer-defining-mold-cavity-section is at least as thick as said second-cavity-flow-channel.