METHOD FOR JOINING A METAL COMPONENT AND A POLYMER COMPONENT, AND STRUCTURE COMPRISING SAID COMPONENTS

Abstract

The invention concerns a method for joining a metal component and a polymer component, and a structure comprising said components. In the method, an extrusion die plate with a through hole is placed between the metal component and the polymer component. A probe is rotated and plunged across the thickness of the metal component and eventually through said through hole of the extrusion die plate, thereby extruding a part of the metal component through said through hole of the extrusion die plate into the polymer component. The probe has a rotation axis having an offset to the centre of the through hole during the rotating and plunging action.

Claims

1-10. (canceled)

11. A method for joining a metal component and a polymer component, the method comprising: obtaining a metal component and a polymer component; obtaining an extrusion die plate having one through hole; placing the extrusion die plate between said metal component and said polymer component; rotating and plunging a probe of a non-consumable and rigid tool across the thickness of the metal component and eventually through said through hole of the extrusion die plate, thereby extruding a part of the metal component through said through hole of the extrusion die plate into the polymer component, wherein the probe has a rotation axis having an offset to the centre of said through hole of the extrusion die plate during the rotating and plunging action.

12. A method according to claim 11, wherein the method further comprises retracting the probe of the tool, and allowing the polymer component to flow back to a cavity in the metal component created by the rotation and plunging of the probe.

13. A method according to claim 11, wherein the tool comprises a shoulder, and the method further comprises moving the shoulder of the tool in contact with a free surface of the metal component.

14. A method according to claim 11, wherein the rotating and plunging action produces a hook of extruded metal of the metal component into the polymer component.

15. A method according to claim 11, wherein the metal component comprises aluminium.

16. A method according to claim 11, wherein the metal component and the polymer component are joined by adhesive, diffusion and clinging joining mechanisms.

17. A method according to claim 11, wherein the method further comprises: travelling the probe of the tool while rotating and plunging the probe of the tool.

18. A structure comprising a metal component and a polymer component having a spot welding or dissimilar overlap joint between said metal component and said polymer component, wherein the structure comprises an extrusion die plate disposed between overlapping metal component and polymer component, which extrusion die plate has one or more through holes, wherein the structure comprises a non-axis-symmetrical hook made of the metal component and extruded into the polymer component through said one or more through holes.

19. A structure according to claim 18, wherein the metal component comprises aluminium.

20. A structure according to claim 18, wherein the metal component and the polymer component have been joined by adhesive, diffusion and clinging joining mechanisms.

21. A method according to claim 12, wherein the tool comprises a shoulder, and the method further comprises moving the shoulder of the tool in contact with a free surface of the metal component.

22. A method according to claim 21, wherein the rotating and plunging action produces a hook of extruded metal of the metal component into the polymer component.

23. A method according to claim 22, wherein the metal component comprises aluminium.

24. A method according to claim 23, wherein the metal component and the polymer component are joined by adhesive, diffusion and clinging joining mechanisms.

25. A method according to claim 24, wherein the method further comprises: travelling the probe of the tool while rotating and plunging the probe of the tool.

26. A structure according to claim 19, wherein the metal component and the polymer component have been joined by adhesive, diffusion and clinging joining mechanisms.

Description

LIST OF FIGURES

[0013] FIG. 1 presents the components of THE-FSpW process to join the metal component 1 to the polymer component 2, using as non-consumable tools the extrusion die plate 3, with the through hole 4, and the rotating and plungeable tool 5.

[0014] FIG. 2 presents the sequence of THE-FSpW process: left) Start position; right) Extrusion period with the probe in its deepest plunged position forcing the metal component 1 into the polymer component 2.

[0015] FIG. 3 presents the application of THE-FSpW process with local plunge: left) no offset between the axis of the tool 5 and the hole 4; right) small offset between the axis of the tool 5 and the hole 4.

[0016] FIG. 4 presents the application of THE-FSpW process with continuous plunged tool 5, travelling along the path defined by the sequence of holes 4 in the extrusion die plate 3.

[0017] FIG. 5 presents alternative shapes for the probe 5a, of the non-consumable tool 5.

[0018] FIG. 6 presents the surface of the polymer component 2, contacting the extrusion die plate 3, which can be flat (left), or have a shallow hole 2a, aligned with the hole 4, of the extrusion die plate 3.

DETAILED DESCRIPTION

[0019] THE-FSpW is a process to produce spot welds between metal and polymer in an overlap joint. The method uses a thin, non-consumable and rigid extrusion die plate 3, located between the overlapping metal component 1 and polymer component 2 (see FIG. 1), and a non-consumable, rigid plungeable and rotatable tool 5 with a probe 5a and a shoulder 5b. The tools in this process are the extrusion die plate 3 and the tool 5.

[0020] The extrusion die plate 3 has one, or more, through-holes 4, that will serve to extrude the part of the metal component 1, that will be pushed through the hole into the polymer component 2 (FIG. 2). The part of the metal component 1 extruded through the hole 4, is pushed through the hole 4, by the probe 5a of the rotating tool 5, that plunges across the thickness of the metal component 1, and eventually continues through the extrusion hole 4 (FIG. 2). The shoulder 5b of the tool 5 can be rotating, or be static, in permanent contact with the free surface of metal component 1, or following the movement of the probe, and thus just contacting the free surface of metal component 1, when the probe is near its most deep plunged position within the metal component 1. The action of the shoulder is to close the deformation zone of the metallic component 1, avoiding losing material into flash. With this action, if the metal component 1 is locally less resistant than the extrusion die plate, the material from the metal component 1 in the vicinity of the extrusion hole 4, is forced/extruded into the polymer. This portion of processed material from the metal component 1, is forced into the polymer under high pressure and relatively hot, due to the thermomechanical processing action. Adhesive, diffusion and clinging joining mechanisms are thus activated between the metal component 1 and the polymer component 2.

[0021] A particular high level of clinging joining effect is obtained, corresponding to the strongest joint, when the axis of the tool 5 has a small offset in relation to the axis of the extrusion through-hole 4 (FIG. 3). In these conditions, the extruded material has asymmetrical wall thickness and fracture in the lower thickness zone happens during the extrusion process, forming a hook and allowing the material from the polymer component 2, to flow back into the volume of the cavity left free by the tool 5, when this tool 5 retracts at the end of the weld cycle (FIG. 3).

[0022] An alternative approach for the same joining method, is to travel the non-consumable tool continuously plunged, along the path defined by the sequence of holes 4 in the extrusion die plate 3 (FIG. 4). In this approach, the shoulder is always in contact with the free surface of the metal component 1, and the tip of the probe 5a, will travel over the extrusion die plate 3, just plunging deeper locally, within the vicinity of each one of the holes 4 of the extrusion die plate 3.

[0023] The extrusion die plate 3 can be located only at each spot position, with only 1 hole 4. In alternative one extrusion die plate 3, can have 2 or mode holes 4 and serve as extrusion die in multiple locations, with the tool 5 applied via local plunging (FIG. 2 and FIG. 3), or being applied continuously (FIG. 4).

[0024] The probe 5a and the shoulder 5b of the tool 5 can be made in one single component, or made of multicomponent assembled together. The shoulder 5b of the tool 5 can be flat, concave or convex. If the shoulder 5b and probe 5a are made of multicomponent, then the shoulder can be rotating or can be static. If the shoulder 5b and probe 5a are made of multicomponent, then the shoulder can be static in permanent contact with the free surface of the metal component 1, during the plunging and extraction movements of the probe 5a. The probe 5a of the tool 5, can be cylindrical, or conical or combination of conical with cylindrical. Namely, the probe 5a of the tool 5, can be conical at the top, and cylindrical at the tip (FIG. 5), to enable a penetration within the through hole 4, of the extrusion die plate 3. This last solution is the most efficient in extruding the metal component 1, into the polymer component 2.

[0025] The surface of the polymer component 2, contacting the extrusion die plate 3, can be flat, or have a shallow hole 2a, aligned with the hole 4, of the extrusion die plate 3. This shallow blind hole 2a, enables to receive the extruded metal component 1, with controlled forging pressure (FIG. 6).

[0026] The parameters controlling the process THE-FSpW are the following:

[0027] 1. Geometry of the probe 5a

[0028] 2. Geometry of the shoulder 5b

[0029] 3. Rotation speed of the tool 5, or of the probe 5a, if the shoulder 5b is static

[0030] 4. Plunging speed or plunging force of the tool 5

[0031] 5. Dwell time at the maximum plunge depth, in plunging force or vertical position control

[0032] 6. Extraction speed of the tool 5

[0033] 7. Travel speed of the tool 5, if the probe 5a is continuous plunged in the metal component 1, traversing along the path of holes 4 in the extrusion die plate 1

[0034] 8. Offset distance between the axis of the tool and the axis of the hole 4

[0035] 9. Material and thickness of the extrusion die plate 1

[0036] 10. Dimension (including thickness) of the extrusion die plate 1

[0037] 11. Diameter of the hole 4 of the extrusion die plate 1

[0038] 12. Number of hole 4 of the extrusion die plate 1

[0039] 13. Distance between the holes 4, if there are 2 or more holes 4

[0040] 14. Material and thickness of the metal component 1

[0041] 15. Material and thickness of the polymer component 1

NOMENCLATURE

[0042] 1—Metal component; [0043] 2—Polymer component; [0044] 2a—shallow blind hole (optional) in polymer component 2, aligned with the hole-through 4 of the extrusion die plate 3; [0045] 3—Extrusion die plate (thin and rigid plate compared with the metal 1 and the polymer 2, at processing conditions); [0046] 4—Hole through the extrusion die plate; [0047] 5—Non-consumable and rigid welding tool; [0048] 5a—Probe of the non-consumable and rigid welding tool 5; [0049] 5b—Shoulder of the non-consumable and rigid welding tool 5.

CITATIONS

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