Apparatus and for laser preweakening an automotive trim cover for an air bag deployment opening

• US 5,744,776 A
• Filed: 10/31/1994
• Issued: 04/28/1998
• Est. Priority Date: 07/14/1989
• Status: Expired due to Term

• Current Assignee: TIP Engineering Group Incorporated
• Original Assignee: TIP Engineering Group Incorporated
• Inventors: Bauer, David J.
• Primary Examiner(s): Evans, Geoffrey S.
• Application Number:
  US08/332,565
• Time in Patent Office: 1,275 Days
• Field of Search: 219/121.62, 219/121.83, 219/121.68, 219/121.69, 219/121.7, 219/121.71, 219/121.72, 280/728.3
• US Class Current: 219/121.7
• CPC Class Codes: B23K 2103/16 Composite materials , e.g. fibre reinforced
• CPC Class Codes: B23K 2103/172 wherein at least one of the layers is non-metallic
• CPC Class Codes: B23K 2103/32 Material from living organisms, e.g. skins
• CPC Class Codes: B23K 2103/34 Leather
• CPC Class Codes: B23K 2103/38 Fabrics, fibrous materials
• CPC Class Codes: B23K 2103/42 Plastics B23K2103/16 takes precedence
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 26/0006 taking account of the properties of the material involved B23K26/32, B23K26/40 take precedence
• CPC Class Codes: B23K 26/03 Observing, e.g. monitoring, the workpiece
• CPC Class Codes: B23K 26/0344 Observing the speed of the workpiece
• CPC Class Codes: B23K 26/0665 by beam condensation on the workpiece, e.g. for focusing
• CPC Class Codes: B23K 26/123 in an atmosphere of particular gases
• CPC Class Codes: B23K 26/359 by providing a line or line pattern, e.g. a dotted break initiation line
• CPC Class Codes: B23K 26/364 for making a groove or trench, e.g. for scribing a break initiation groove
• CPC Class Codes: B23K 26/389 of fluid openings, e.g. nozzles, jets laser machining of inkjet nozzles B41J2/1634
• CPC Class Codes: B23K 26/40 taking account of the properties of the material involved
• CPC Class Codes: B29C 2035/0838 using laser
• CPC Class Codes: B29C 2791/009 Using laser curing using laser B29C2035/0838, welding using laser beams B29C65/16
• CPC Class Codes: B29C 2793/0054 partially cutting through the material
• CPC Class Codes: B29C 59/007 Forming single grooves or ribs, e.g. tear lines, weak spots by moulding B29C37/0057; folding lines B29C53/06; in metal articles B21D17/00; by cutting B26D3/08
• CPC Class Codes: B29C 59/16 : by wave energy or particle radiation , e.g. infrared heating B29C59/007 takes precedence
• CPC Class Codes: B29L 2031/3005 : Body finishings
• CPC Class Codes: B29L 2031/3008 : Instrument panels
• CPC Class Codes: B29L 2031/3038 : Air bag covers
• CPC Class Codes: B60R 2021/21654 : the tearing being done or assisted by heating or pyrotechnic means
• CPC Class Codes: B60R 21/2165 : characterised by a tear line for defining a deployment opening

Abstract

A process for preweakening the inside of an automotive trim piece cover layer of various constructions by use of a laser beam so as to enable formation of an air bag deployment opening in the trim piece formed at the time the air bag deploys. The laser beam impinges the inside surface of the cover to form a groove scoring or spaced perforations to form a preweakening pattern. A robot arm may be used to move a laser generator so as to form the preweakening pattern. The laser beam can be controlled in accordance with sensed conditions to achieve accurate preweakening, and may also be used to trim substrate panels and to perform other cutting operations.

Claims

1. A process for preweakening an automotive interior trim piece covering an air bag installation, said air bag installation including a folded air bag adapted to be inflated and deployed upon detection of a collision, said preweakening enabling formation of an air bag deployment opening extending through said trim piece by said inflating air bag pushing through said trim piece, said trim piece having a smooth, uninterrupted cover layer overlying a substrate panel associated with an air bag deployment door, comprising the steps of:

separately forming said cover layer and said substrate panel;

scoring an inside surface of said cover layer by directing a laser beam of a predetermined intensity at said inside surface of said cover layer and moving said laser beam over said inside surface in a predetermined scoring pattern while controlling said laser beam so as to produce scoring of said inside surface of said cover layer to a depth on the order of 20-80% of the thickness of said cover layer;

assembling said scored cover layer and substrate panel into a mold with an intervening space therebetween, and with said scoring pattern having a predetermined spatial relationship with said deployment door; and

,

filling said intervening space with a plastic foam layer to bond said cover layer and substrate panel together with said foam layer underlying said scoring pattern.

2. The process according to claim 1 wherein in said scoring steps a CO₂ laser beam is directed at said cover layer inside surface.

3. The process according to claim 2 further including the step of scoring said cover material with said laser beam in a transverse direction with respect to said groove to produce localized preweakening at a selected point along said groove.

4. The process according to claim 2 further including the step of back filling said groove with a diverse material.

5. The process according to claim 2 wherein said CO₂ laser beam is of constant intensity and said laser beam is moved along said pattern at a rate forming a constant depth groove.

6. The process according to claim 2 wherein said CO₂ laser beam intensity is varied and is moved at a controlled rate to create a controlled depth and width of said preweakening scoring.

7. The process according to claim 1 further including the step of sensing the thickness of said cover layer at each point along the path of said laser beam and varying the scoring effect produced by said laser beam so as to maintain a predetermined remaining thickness of said cover layer along said scoring pattern.

8. The process according to claim 7 wherein said layer cover is formed from a dry powder slush having a rough texture on said inside surface, said scoring step causing a varying depth groove to be formed with said laser beam scoring of said rough textured inside surface.

9. The process according to claim 1 wherein said trim piece comprises a molded plastic steering wheel cover and in said scoring steps a groove is formed by said laser beam.

10. The process according to claim 1 further including the step of completely severing a portion of said cover layer by directing a laser beam at said cover and relatively moving said laser beam to sever said portion therefrom.

11. The process according to claim 1 further including the step of assembling said cover to a substrate to form said trim piece, and further including the steps of trimming said trim piece with said laser beam.

12. The process according to claim 1 wherein said CO₂ laser beam is varied in intensity or speed to create a scoring in said cover layer comprised of a groove of a varying depth.

13. The process according to claim 1 further including the step of mounting a laser beam generator to a robot arm and moving said robot arm to direct said laser beam from said laser beam generator at said cover layer inside surface along a path such as to score said cover layer in said pattern.

14. The process according to claim 13 further including gaging said cover layer with a gaging laser beam by moving a laser generator with a robot arm so as to impinge portions of said cover layer along a path just ahead of said scoring of said cover, generating gaging signals corresponding to any surface variance of said cover layer portions, and adjusting the scoring produced by said laser beam generator in correspondence therewith so as to maintain a substantially constant material thickness remaining above the scoring of said cover layer.

15. The process according to claim 14 wherein the speed of movement of said laser beam generator is varied in accordance with said gaging signals.

16. The process according to claim 1 wherein said laser beam is operated intermittently to create a scoring comprised of a series of holes in said cover.

17. Apparatus for prescoring an inside of an automotive interior trim piece having a substrate and an overlying cover piece, comprising:

a CO₂ laser beam generator of sufficient power to partially penetrate said interior trim piece;

means for supporting said trim piece and relatively moving said supported trim piece and laser beam generator to trace a scoring pattern on said interior trim piece with a laser beam to form an air bag deployment door therein; and

,

control means monitoring said scoring of said trim piece during the tracing of the scoring pattern on said interior trim piece, and varying the scoring effect of said laser beam to produce only a predetermined partial penetration of said interior trim piece by said laser beam at points along the tracing of said scoring pattern.

18. The apparatus according to claim 17 wherein said control means includes sensor means for sensing the outer surface of said trim piece cover layer to vary the groove depth so as to maintain a constant thickness of remaining material.

19. A process for preweakening an automotive interior trim piece covering an air bag installation, said air bag installation including a folded air bag adapted to be inflated and deployed upon detection of a collision, said preweakening enabling formation of an air bag deployment opening extending through said trim piece by said inflating air bag pushing through said trim piece, said trim piece having a smooth, uninterrupted covering skin layer overlying a substrate panel associated with an air bag deployment door, comprising the steps of:

separately forming said covering skin layer and said substrate panel;

scoring one side of said covering skin layer by directing a laser beam of a predetermined intensity at said one side of said covering skin layer and moving said laser beam over said covering skin layer in a predetermined scoring pattern while controlling said laser beam so as to produce scoring of said inside surface of said covering skin layer to a depth on the order of 20% or greater of the thickness of said covering skin layer; and

,

thereafter mounting said covering skin layer to said substrate panel with said scoring pattern on the inside of said covering skin layer facing said substrate.

20. The process according to claim 19 wherein said covering skin layer comprises a skin preformed with a foam backing layer.

21. The process according to claim 19 wherein in said scoring steps a CO₂ laser beam is directed at said covering skin layer inside surface.

22. The process according to claim 21 further including the step of sensing the thickness of said covering skin layer at each point along the path of said laser beam and varying the scoring effect produced by said laser beam so as to maintain a predetermined remaining thickness of said covering skin layer along said scoring pattern.