WO2005110703A1

WO2005110703A1 - Injection forming and bonding process

Info

Publication number: WO2005110703A1
Application number: PCT/US2005/016204
Authority: WO
Inventors: Stephen R. Roddy; Keijo J. Huotari; James R. Drouillard; Payman Afshari; Jeffrey Lohnes; Donald J. Duclos; Philip Grella
Original assignee: Decoma International
Priority date: 2004-05-07
Filing date: 2005-05-09
Publication date: 2005-11-24

Abstract

A method of bonding a plastic material (40) to a metal structure (28) having an interlock element (30) utilizes a mold assembly (42) having a passageway (18) fitted with an ejector pin (22). The method includes the steps of placing the metal structure (28) inside the mold assembly (12) so that the interlock element (30) is disposed within the passageway (18); injecting the plastic material (40) into the mold assembly (12) at a predetermined pressure to force the interlock element (30) to conform to the passageway (18); and moving the ejector pin (22) to crimp the interlock element (30) in order to provide a positive interlock between the plastic material (40) and the metal structure (28).

Description

INJECTION FORMING AND BONDING PROCESS

Field of the Invention

[0001] The invention relates to a composite component for a motor vehicle. More particularly, the invention is related to a method of bonding a plastic material to a metal member via an injection forming process to form a composite component for a motor vehicle.

Description of Related Art

[0002] The use of composites has gained increased acceptance in the manufacturing of certain motor vehicle components. Such composite components, which are generally formed from metal and plastic, are lighter in weight and more cost-effective to produce than their metal counterparts. For these composite components, it is important to form a stable bond between the metal and the plastic. One well-known method for joining the plastic to the metal involves injection molding the plastic onto a sheet metal part.

[0003] United States Patent 5,190,803 discloses injection molding a plastic material to a metal shell. The metal shell includes injected-on plastic reinforcing ribs extending along an interior surface. The reinforcing ribs are connected to the metal sheet at connecting points via perforations. More specifically, the plastic material passes through the perforations to anchor the reinforcing ribs to the metal shell. United States Patent 5,842,265 discloses using injection molding to bond a plastic material to a pair of metal sheets. The metal sheets are placed in a mold such that openings in each are aligned with one another. A plastic material in injected into the mold and flows through the openings. As a result, a bond is formed between the metal sheets and the plastic part.

Summary of the Invention

[0004] According to one aspect of the invention, a method of bonding a plastic material to a metal structure having an interlock element utilizes a mold assembly having a passageway fitted with an ejector pin. The method includes the steps of: placing the metal structure inside the mold assembly so that the interlock element is disposed within. the passageway; injecting the plastic material into the mold assembly at a predetermined pressure to force the interlock element to conform to the passageway; and moving the ejector pin to crimp the interlock element in order to provide a positive interlock between the plastic material and the metal structure. [0005] According to another aspect of the invention, a method of bonding a plastic material to a metal structure, having an interlock element, and a sheet layer, having an aperture, utilizes a mold assembly having a mold surface defining a passageway fitted with an ejector pin. The method includes the steps of: placing the sheet layer along the mold surface so that the aperture is aligned with the passageway; positioning the metal structure along the sheet layer so that the interlock element extends through the aperture and into the passageway; injecting the plastic material into the mold assembly at a predetermined pressure to force the interlock element to conform to the passageway; and moving the ejector pin to clamp the interlock element around a portion of the sheet layer and provide a positive interlock between the plastic material and the metal structure.

[0006] According to yet another aspect of the invention, a method of bonding a plastic material to a sheet layer having an aperture utilizes an interlock element and a mold assembly having a mold surface defining a passageway fitted with an ejector pin. The method includes the steps of: placing, the sheet layer along the mold surface so that the aperture is aligned with the passageway; positioning the interlock element along the sheet layer so that a portion of the interlock element extends through the aperture and into the passageway; injecting the plastic material into the mold assembly at a predetermined pressure to force the interlock element to conform to the passageway; and moving the ejector pin to crimp the interlock element in order to provide a positive interlock that joins the plastic material to the sheet layer.

Brief Description of the Drawings

[0007] Advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

[0008] Figure 1 is a cross-sectional view of a mold assembly and a metal structural member positioned therewithin in a first embodiment of the invention;

[0009] Figure 2 is a cross-sectional view similar to Figure 1 including an injected plastic material being injected into an interlock element of the structural member while positioned in a passageway of the mold assembly; [0010] Figure 3 is a cross-sectional view similar to Figure 2 showing deformation of a side wall of the interlock element;

[0011] Figure 4 is a cross-sectional view similar to Figure 3 including an ejector pin in an extended position for further deforming the side wall of the interlock element;

[0012] Figure 5 is a cross-sectional view of a composite component including the plastic material securely bonded to the structural member;

[0013] Figure 6 is a cross-sectional view of a metal structural member and a sheet layer positioned inside a mold assembly in a second embodiment of the invention;

[0014] Figure 7 is a cross-sectional view similar to Figure 6 including an injected plastic material being injected into an interlock element of the structural member that is received within an aperture of the sheet layer;

[0015] Figure 8 is a cross-sectional view similar to Figure 7 showing deformation of a side wall of the interlock element;

[0016] Figure 9 is a cross-sectional view similar to Figure 8 including an ejector pin in an extended position for further deforming the side wall of the interlock element to clamp the sheet layer;

[0017] Figure 10 is a cross-sectional view of a composite component including the plastic material securely bonded to the structural member;

[0018] Figure 11 is a cross-sectional view of an interlock element and a sheet layer positioned inside a mold assembly in a third embodiment of the invention;

[0019] Figure 12 is a cross-sectional view similar to Figure 11 including an injected plastic material being injected into the interlock element positioned within an aperture of the sheet layer;

[0020] Figure 13 is a cross-sectional view similar to Figure 12 showing deformation of a side wall of the interlock element; [0021] Figure 14 is a cross-sectional view similar to the Figure 13 including an ejector pin in an extended position for further deforming the side wall of the interlock element to clamp the sheet layer; and

[0022] Figure 15 is a cross-sectional view of a composite component including the plastic material joined to the sheet layer by the interlock element.

Detailed Description of the Preferred Embodiment

[0023] Referring to Figure 1, a mold assembly, generally shown at 10, includes a lower die half 12 and an upper die half (not shown) defining a mold cavity 14 therebetween. The upper die half is movable relative to the lower die half 12. It is, however, appreciated that the lower die half 12 may be movable relative to the upper die half or that both of the lower 12 and upper die halves may be movable. The lower die half 12 includes a mold surface 16.

[0024] The mold surface 16 includes at least one passageway, generally indicated at

18. Each passageway 18 includes an outer wall 20. An ejector pin 22 having an upper surface 24 is slidably disposed within the passageway 18 and is sized to close the passageway 18. The ejector pin 22 is movable between a retracted position, shown in Figures 1 through 3, an extended position, shown in Figure 4, and an eject position (not shown). In each of the retracted and extended positions, the upper surface 24 of the ejector pin 22 is recessed from the mold surface 16. hi the eject position, the upper surface 24 of the ejector pin 22 extends past the mold surface 16 and out of the lower die half 12 to dislodge the finished component from the mold assembly 10. A suitable drive (not shown) is operably connected to the ejector pin 22 to provide driving movement thereof, as is well-known to those skilled in the art.

[0025] A sheet metal structure, generally indicated at 28, includes a main portion 29 and at least one deformable button or interlock element 30. The metal structure 28 is positioned on the lower die half 12 such that each interlock element 30 is disposed within one of the passageways 18. The interlock element 30 is generally an inverted hat shape having a bottom wall 32 and a side wall 34. In a preferred embodiment, the bottom wall 32 is circular and the side wall 34 extending up therefrom is annular having an expanding diameter. It is, however, contemplated that the particular shape of the bottom wall 32 and the side wall 34 may vary. An annular edge 36 of the interlock element 30, where the side wall 34 merges with the main portion 29 of the metal structure 28, is slightly elevated relative to the main portion 29 of the metal structure 28.

[0026] Referring to Figure 2, an organic plastic material 40 is injected into the mold assembly 10 after the upper and lower 12 die halves are closed against one another. The plastic material 40 is injected at a predetermined injection pressure, as is well-known to those skilled in the art. The predetermined pressure at which the plastic material 40 is injected is sufficient to force the side wall 34 of the interlock element 30 outwardly against the outer wall 20 of the passageway 18.

[0027] Referring to Figure 3, as the passageway 18 fills and begins to pack out, the annular edge 36 is urged against the mold surface 16 and towards the bottom wall 32, which causes the side wall 34 to deform outwardly. More specifically, the side wall 34 is deformed so that a first segment 42 thereof is pinched or folded over and a second segment 44 thereof is expanded outwardly against the outer wall 20 of the passageway 18.

[0028] Referring to Figure 4, the ejector pin 22 is driven upwards into the extended position (in the direction of arrow D) as the plastic material 40 is forcing the interlock element 30 against the ejector pin 22. More specifically, the first segment 42 is further pinched or folded over and the second segment 44 is further expanded outwards to crimp the side wall 34. This further pinching and expanding enables a positive interlock between the plastic material 40 and the interlock element 30. It is appreciated that although an ejector pin is shown forcing the bottom wall 32 upwards in the direction of arrow D, any mechanism or method that achieves similar upward movement of the bottom wall 32 may be utilized.

[0029] Referring to Figure 5, after the plastic material 40 is cured, the plastic material

40 is securely bonded to the interlock element 30 to form a composite component, generally shown at 46. The cured plastic material 40 maintains the interlock element 30 in the crimped shape so that the interlock element 30 is interlocked in a positive and stable configuration. It should be appreciated that for a typical composite component 46, a plurality of interlock elements 30 will be utilized to join the plastic material 40 to the metal structure 28 at numerous locations in order to effect an even stronger bond therebetween.

[0030] Referring to Figures 6 through 10, a second embodiment of the present invention is illustrated. The second embodiment is similar to the first embodiment except that a sheet layer 121 is positioned on the mold surface 16. The sheet layer 121 includes an aperture 123 positioned to overlay each passageway 18. Each aperture 123 is preferably sized slightly less than the size of the passageways 18. The sheet layer 121 is preferably a single layer of sheet metal. It will, however, be apparent to those skilled in the art that the sheet layer 121 may incorporate more than one layer and other sheet materials.

[0031] The metal structure 128 is provided with at least one interlock element 130 each including the bottom wall 132, the side wall 134, and the annular edge 136 for merging the side wall 134 with the main portion 129 of the metal structure 128. The interlock element 130 is positioned to extend through the aperture 123 of the sheet layer 121 to sit within the passageway 18. When the mold assembly 10 is closed, the plastic material 140 is injected into the mold cavity 14 at a predetermined injection pressure, as in the first embodiment. As the ejector pin 22 is moved from the retracted position to the extended position, as shown in Figure 9, the side wall 134 folds over at the first 142 and second 144 segments. As a result, the sheet layer 121 is sandwiched and clamped between the side wall 134 and the annular edge 136 while the plastic material 140 is bonded to the interlock element 130 to form the composite structure 146, as shown in Figure 10. The plastic material 140 is then cured to securely bond the plastic material 140 to the interlock element 130.

[0032] Referring to Figures 11 through 15, a third embodiment of the invention is illustrated. In the third embodiment, the interlock element 230 is a discrete structure including the bottom wall 232, the side wall 234, and the annular edge 236. The interlock element 230 is received within the aperture 223 of the sheet layer 221 and extends into the passageway 18. When the mold assembly 10 is closed, the plastic material 240 is injected into the mold cavity 14 at a predetermined injection pressure, as in the first and second embodiments. As the ejector pin 22 is moved from the retracted position to the extended position, as shown in Figure 14, the side wall 234 folds over at the first 242 and second 244 segments. The sheet layer 221 is thus sandwiched and clamped between the side wall 234 and the annular edge 236 of the interlock element 230. At the same time, the crimping of the side wall 234 provides a positive interlock between the plastic material 240 and the interlock element 230. The plastic material 240 is then cured to securely bond the plastic material 240 to the interlock element 230. As a result, the plastic material 240 is joined to the sheet layer 221. [0033] The methods according to the invention may be used to form numerous composite components for a motor vehicle including, but not limited to, integration panels for end modules, door frames and front and rear body panels.

[0034] The invention has been described in an illustrative manner, and it is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced other than as specifically described.

Claims

What is claimed: 1. A method of bonding a plastic material to a metal structure having an interlock element via a mold assembly including a passageway fitted with an ejector pin, the method comprising the steps of: placing the metal structure inside the mold assembly so that the interlock element is disposed within the passageway; injecting the plastic material into the mold assembly at a predetermined pressure to force the interlock element to conform to the passageway; and moving the ejector pin to crimp the interlock element in order to provide a positive interlock between the plastic material and the metal structure.

2. A method as set forth in claim 1 including the step of curing the plastic material after the step of moving the ejector pin to crimp the interlock element in order to provide a positive interlock between the .plastic material and the metal structure.

3. A method as set forth in claim 2 including the step of ejecting the metal structure having the plastic material joined thereto from the mold assembly after the step of curing the plastic material.

4. A method as set forth in claim 3 wherein the step of moving the ejector pin to crimp the interlock element in order to provide a positive interlock between the plastic material and the metal structure occurs during the step of injecting the plastic material into the mold assembly at a predetermined pressure to force the interlock element to conform to the passageway.

5. A method as set forth in claim 4 wherein the step of injecting the plastic material into the mold assembly at a predetermined pressure to force the interlock element to conform to the passageway includes the step of partially deforming the interlock element.

6. A method as set forth in claim 5 including the step of closing the mold assembly prior to the step of injecting the plastic material into the mold assembly at a predetermined pressure to force the interlock element to conform to the passageway.

7. A method of bonding a plastic material to a metal structure, having an interlock element, and a sheet layer, having an aperture, via a mold assembly having a mold surface defining a passageway fitted with an ejector pin, the method comprising the steps of: placing the sheet layer along the mold surface so that the aperture is aligned with the passageway; positioning the metal structure along the sheet layer so that the interlock element extends through the aperture and into the passageway; injecting the plastic material into the mold assembly at a predetermined pressure to force the interlock element to conform to the passageway; and moving the ejector pin to clamp the interlock element around a portion of the sheet layer and provide a positive interlock between the plastic material and the metal structure.

8. A method as set forth in claim 7 including the step of curing the plastic material after the step of moving the ejector pin to clamp the interlock element around a portion of the sheet layer and provide a positive interlock between the plastic material and the metal structure.

9. A method as set forth in claim 8 wherein the step of moving the ejector pin to clamp the interlock element around a portion of the sheet layer and provide a positive interlock between the plastic material and the metal structure occurs during the step injecting the plastic material into the mold assembly at a predetermined pressure to force the interlock element to conform to the passageway.

10. A method of bonding a plastic material to a sheet layer having an aperture via an interlock element and a mold assembly having a mold surface defining a passageway fitted with an ejector pin, the method comprising the steps of: placing the sheet layer along the mold surface so that the aperture is aligned with the passageway; positioning the interlock element along the sheet layer so that a portion of the interlock element extends through the aperture and into the passageway; injecting the plastic material into the mold assembly at a predetermined pressure to force the interlock element to conform to the passageway; and moving the ejector pin to crimp the interlock element in order to provide a positive interlock that joins the plastic material to the sheet layer.

11. A method as set forth in claim 10 including the step of curing the plastic material after the step of moving the ejector pin to crimp the interlock element in order to provide a positive interlock that joins the plastic material to the sheet layer.

12. A method as set forth in claim 11 including the step of ejecting the sheet layer joined with the plastic material via the interlock element from the mold assembly after the step of curing the plastic material.

13. A method as set forth in claim 12 wherein the step of moving the ejector pin to crimp the interlock element in order to provide a positive interlock that joins the plastic material to the sheet layer occurs during the step injecting the plastic material into the mold assembly at a predetermined pressure to force the interlock element to conform to the passageway.

14. A method as set forth in claim 13 wherein the step of moving the ejector pin to crimp the interlock element in order to provide a positive interlock that joins the plastic material to the sheet layer includes the step of sandwiching a portion of the sheet layer between the crimped interlock element.

15. A method as set forth in claim 14 including the step of closing the mold assembly prior to the step of injecting the plastic material into the mold assembly at a predetermined pressure to force the interlock element to conform to the passageway.