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

• US 6,267,918 B1
• Filed: 06/25/1999
• Issued: 07/31/2001
• Est. Priority Date: 10/31/1994
• Status: Expired due to Term

• Current Assignee: TIP Engineering Group Incorporated
• Original Assignee: TIP Engineering Group Incorporated
• Inventors: Bauer, David J.
• Primary Examiner(s): Vargot, Mathieu D.
• Application Number:
  US09/339,885
• Time in Patent Office: 767 Days
• Field of Search: 264/400, 264/482, 264/156, 264/40.1, 425/174.4, 425/141, 219/121.68, 219/121.69, 219/121.71, 219/121.83, 219/121.7
• US Class Current: 264/400
• 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 constructing a preweakened automotive interior trim piece covering an air bag installation, said preweakening applied in a predetermined pattern in a particular location so as to enable formation of an air bag deployment opening in said trim piece, said opening formed by pressure exerted by deployment of an air bag from said installation, said trim piece having a cover layer with an outer surface visible from within said vehicle interior and extending smoothly and uninterruptedly across said preweakening at said particular location, said trim piece also having an inside surface, said process including the steps of:

preweakening said trim piece by directing a CO₂ laser beam along said inside surface of said trim piece to produce said preweakening by removing material from said trim piece along said predetermined pattern;

monitoring the extent of material remaining during removal of material by said laser beam; and

,

controlling the extent of material removed by said laser beam in accordance with the results of said monitoring step to effect a predetermined preweakening of said trim piece in said predetermined pattern by removing material on an inner side of said cover layer to remove material so as to produce a series of spaced apart partial penetrations in said cover layer spaced along said predetermined pattern, said partial penetrations not extending into said outer surface of said cover layer to form a stepped depth configuration.

2. The process according to claim 1 wherein said monitoring step includes the step of sensing material thickness from said outside surface of said cover layer along said predetermined pattern to determine the material thickness remaining during preweakening by said laser beam.

3. The process according to claim 1 wherein said monitoring step includes the step of sensing material thickness from said inside surface of said trim piece to determine the preweakening effected by said laser beam.

4. The process according to claim 1 wherein said preweakening is continuous on inner regions of said trim piece behind said cover layer.

5. The process according to claim 1 wherein said laser is operated intermittently to form said partial penetrations.

6. The process according to claim 1 wherein said controlling step includes the step of controlling operation of a laser beam generator generating said laser beam.

7. The process according to claim 6 further including the step of changing the relative position of said trim piece and said laser beam generator to cause said laser beam to be directed at said trim piece along said predetermined pattern.

8. The process according to claim 1 wherein said trim piece has a multi-layer construction including an inside rigid substrate layer, said cover layer, and an intervening foam layer.

9. The process according to claim 1 wherein said laser beam is pulsed to produce said partial penetrations.

10. The process according to claim 8 wherein said substrate is continuously completely cut by said laser beam in said preweakening step.

16. The process according to claim 9 wherein said controlling step includes the step of applying a particular number of pulses corresponding to the results of said monitoring step to said trim piece at each of a series of sites on said trim piece.

11. A process for constructing a preweakened automotive interior trim piece covering an air bag installation, said preweakening applied in a predetermined pattern in a particular location so as to enable formation of an air bag deployment opening in said trim piece for an air bag installation covered at said location by pressure exerted by deployment of said air bag, said trim piece having an outer cover layer visible from within said vehicle interior and extending smoothly and uninterruptedly across said preweakening at said particular location, said trim piece including a rigid substrate layer underlying said cover layer said process including the steps of:

preweakening said trim piece by directing a CO₂ laser beam at an inside surface of said substrate layer to remove material from said trim piece;

locating a sensor on the outside of said trim piece cover layer opposite said laser beam, said sensor producing output signals corresponding to material thickness measured along said predetermined pattern;

monitoring the extent of preweakening effected by said laser beam during said preweakening to determine the material thickness remaining by analyzing said sensor output signals along said predetermined pattern;

controlling the extent of preweakening effected by said laser beam in accordance with the results of said monitoring step to produce a complete penetration of said substrate layer along said predetermined pattern and partial penetration of said cover layer at spaced apart locations along said predetermined pattern to form a stepped depth configuration; and

changing the relative position of said laser beam and said trim piece to effect a predetermined level of preweakening of said trim piece along said predetermined pattern.

12. The process according to claim 11 wherein said controlling step includes the step of controlling operation of a laser beam generator generating said laser beam.

13. The process according to claim 12 wherein a change in relative position of said trim piece and said laser beam generator causes said laser beam to be directed along said predetermined pattern.

14. The process according to claim 11 wherein said trim piece comprises a construction having a foam layer in between said substrate and skin layer.

15. The process according to claim 11 wherein in said preweakening step said laser beam is pulsed.

17. The process according to claim 15 wherein said controlling step includes the step of applying a particular number of pulses corresponding to the results of said monitoring step to said trim piece at each of a series of sites on said trim piece.

18. The process according to claim 11 wherein said preweakening penetrates 20 to 80% of the thickness of said trim piece.