Hyrbid welding of thermoplastics

Abstract

A process for welding of at least two separate vehicle panels (12, 14) to form an integral part (16) for a vehicle. There is provided at least one first panel (12) including a first weld line area (18) and at least one second panel (14) including a corresponding second weld line area (19), the second weld line area (19) abutting in a weldable relationship to the first weld line area (18). The first and second weld line areas (18, 19) have at least one first weldable portion (22) and at least one second portion (24) at which welding is substantially hindered during welding attachment of the first and second panels (12, 14). The process includes applying a curable adhesive at each second portion (24), placing in a welding fixture and welding the panels (12, 14) at each first weldable portion (22) such that the panels (12, 14) are held together during curing of the adhesive.

Claims

1. A process for welding of two separate polymer vehicle panels to form an integral part for a vehicle, comprising: providing a first polymer panel including a first elongated weld line area at least along an edge said panel; providing a second polymer panel including a corresponding second elongated weld line area at least along an edge of said panel, said second weld line area for abutting in a weldable relationship to the first weld line area wherein said first and second weld line areas have elongated area at which welding is substantially hindered during welding attachment of the first and second polymer panels; applying a curable adhesive at said second elongated weld line portion, wherein the curable adhesive is not heat curable, and placing said first and second polymer panels in welding position; and, welding said first and second polymer panels at said first elongated weld line area such that said first and second polymer panels are held together during curing of said adhesive.

2. The process for welding of two separate polymer vehicle panels to form an integral part for a vehicle of claim 1, wherein there are a plurality of first weldable portions and second portions.

3. The process for welding of two separate polymer vehicle panels to form an integral part for a vehicle of claim 1, wherein said adhesive is a urethane adhesive.

4. The process for welding of two separate polymer vehicle panels to form an integral part for a vehicle of claim 3, wherein the adhesive is water cured.

5. The process for welding of two separate polymer vehicle panels to form an integral part for a vehicle of claim 1, wherein the second portion is at an area of changed geometry.

6. The process for welding of two separate polymer vehicle panels to form an integral part for a vehicle of claim 1, further comprising flame treating the second portion prior to applying the adhesive for enhancing adhesiveness of the panel material.

7. The process for welding of two separate polymer vehicle panels to form an integral part for a vehicle of claim 1, further comprising applying primer to the second portion prior to applying the adhesive for enhancing adhesiveness of the panel material.

8. The process for welding of two separate polymer vehicle panels to form an integral part for a vehicle of claim 1, further comprising painting at least the first panel prior to applying the adhesive.

9. The process for welding of two separate polymer vehicle panels to form an integral part for a vehicle of claim 1, further comprising loading the first and second panels into a welding fixture prior to welding said panels.

10. The process for welding of two separate polymer vehicle panels to form an integral part for a vehicle of claim 1, wherein the panels form a rear liftgate.

11. The process for welding of two separate polymer vehicle panels to form an integral part for a vehicle of claim 1, wherein the welding process is a resistive implant welding process.

12. A process for welding of two separate polymer vehicle panels to form an integral part for a vehicle, comprising: providing a first polymer panel including a first weld line area; providing a second polymer panel including a corresponding second weld line area, said second weld line area for abutting in a weldable relationship to the first weld line area wherein said first and second weld line areas have an elongated weld line at least adjacent and edge portion of a panel an elongated area including at which welding is substantially hindered during welding attachment of the first and second polymer panels; applying a heat resistive adhesive at said second portion and placing said first and second polymer panels in welding position, wherein the second portion is an elongated weld line at an area of abrupt surface change geometry; and, welding said first and second polymer panels at said first weldable portion such that said first and second polymer panels are held together during curing of said adhesive.

13. The process for welding of two separate polymer vehicle panels to form an integral part for a vehicle of claim 12, wherein the adhesive is moisture curable adhesive.

14. The process for welding of two separate polymer vehicle panels to form an integral part for a vehicle of claim 13, wherein the adhesive is a urethane adhesive.

15. A process for welding of two separate polymer vehicle panels to form an integral part for a vehicle, comprising: providing a first polymer panel including a first elongated weld line area; providing a second polymer panel including a corresponding second elongated weld line area, said second weld line area at least adjacent an edge portion of the first and second panel for abutting in a weldable relationship to the first weld line area wherein said first and second weld line areas have an elongated weld line area at which welding is substantially hindered during welding attachment of the first and second panels; applying a curable adhesive at said elongated weld line area, wherein the curable adhesive is not heat curable, and placing said first and second polymer panels in welding position; and, welding said first and second polymer panels at said first weldable portion or second portion such that said first and second polymer panels are held together during curing of said adhesive.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

(2) FIG. 1 is a perspective view of a rear liftgate manufactured in accordance with the teachings of the present invention;

(3) FIG. 2 is an exploded perspective view of the liftgate of FIG. 1;

(4) FIG. 3 is a sectional view of the liftgate of FIGS. 1 and 2 showing weld line areas in a typical welding process;

(5) FIG. 4 is a detailed sectional view showing a weldable area of the part illustrated in FIGS. 1 and 2; and,

(6) FIG. 5 is a detailed sectional view showing a typical area which is not readily weldable where adhesive would be applied in accordance with the process of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(7) The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

(8) In accordance with the present invention there is provided a process generally indicated at 10 for welding of at least two separate vehicle panels 12 and 14 to form an integral part generally indicated at 16 for a vehicle, e.g., such as a composite rear liftgate for a sport utility vehicle (SUV).

(9) In the process 10 a first panel 12 (here shown as an outer panel) is provided which includes at least a first weld line area shown generally at 18 which provides the desired points or areas of attachment shown generally at 20 between the first panel 12 and a second panel 14 (here shown as an inner panel). The weld line is typically along the outer edge areas of the panels 12,14. Where the contour of the first and second panels 12,14 change to vertical (when the panels 12,14 are horizontal on a welding fixture) such as at the tail light opening, welding becomes problematic. The second panel 14 is provided including at least a corresponding second weld line area shown generally at 19 which corresponds to the areas of attachment 20 of the first panel 12 and abutting in a weldable relationship to the first weld line area 18. The first and second weld line areas 18,19 include a first weldable portion 22, and a second portion 24 at which welding is substantially hindered during welding attachment of the first 12 and second 14 panels.

(10) A curable adhesive is provided and applied at the second portion 24. The adhesive can be any adhesive that is heat resistant and provides a solid bond at the portion of the panels. In a preferred process welding is accomplished by infrared welding techniques where heat is generated. In a preferred process adhesives which are not curable, cured or otherwise heat sensitive is used to avoid premature curing of the adhesive before or during welding. By way of illustration but not limitation a moisture curable urethane adhesive such as a BETASEAL 1 windshield adhesive available from Dow™ Chemical of Midland Mich. is suitable for use in the areas which are not easily welded. Prior to this step the first and second panels 12,14 of course are molded and painted for the final assembly and pre-assembled, as required. As an option, areas which adhesive is to be applied are preferably flame treated and primed to provide superior bonding of the adhesive.

(11) The first and second panels 12,14 are then placed in position for welding in a welding fixture or the like. The first and second panels 12,14 are then welded at the first weldable portion 22 such that the panels 12,14 are held together during curing of said adhesive. Welding can be accomplished by laser, ultrasonic, vibration, infrared, resistive implant welding or other conventional plastics welding techniques. A particularly preferred welding technique is infrared welding of the parts in the subject invention.

(12) The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.