Dual paint coat laser-marking labeling system, method, and product

• US 6,746,724 B1
• Filed: 11/01/2000
• Issued: 06/08/2004
• Est. Priority Date: 04/11/1997
• Status: Expired due to Term

• Current Assignee: InfoSight Corporation
• Original Assignee: InfoSight Corporation
• Inventors: OʼNeal, Edward S., Robertson, John A.
• Primary Examiner(s): PADGETT, MARIANNE L
• Application Number:
  US09/704,077
• Time in Patent Office: 1,315 Days
• Field of Search: 427/555, 427/556, 427/230, 427/235, 427/239, 427/554, 219/121.69, 219/121.8, 219/121.85
• US Class Current: 427/555
• CPC Class Codes: B05D 3/06 by exposure to radiation B05D3/02 takes precedence ; plasma treatment B05D3/141
• CPC Class Codes: B05D 5/06 to obtain multicolour or other optical effects B05D5/02 takes precedence
• CPC Class Codes: B05D 7/222 of pipes
• CPC Class Codes: B05D 7/534 the first layer being let to dry at least partially before applying the second layer B05D7/538 takes precedence
• CPC Class Codes: B41M 5/267 Marking of plastic artifacts, e.g. with laser
• CPC Class Codes: B41M 7/0027 using protective coatings or layers by lamination or by fusion of the coatings or layers
• CPC Class Codes: F16L 11/124 Distinguishing marks for hoses
• CPC Class Codes: F16L 2201/60 Identification or marking
• CPC Class Codes: G09F 3/00 Labels, tag tickets, or similar identification or indication means medals or badges A44C3/00; making labels B31D1/02; sheets temporarily attached together B42F; labelling B65C; labels on record carriers G11B23/38, G11B23/40; Seals; Postage or like stamps

Abstract

The present invention is directed to a system for marking objects for their identification which marks survive elevated temperatures of, say, up to 600° to 800° F. or higher, for extended periods of time. The inventive system for marking workpieces for their identification includes a laser that emits a beam select band of radiation and a coating system for application to a workpiece to be marked. The coating system includes two coats of paint, a topcoat and a basecoat which paints have been coated sequentially on the workpiece. The basecoat is an at least partially-cured, laser-blackenable paint which has been marked with fragile product identification indicia by the laser beam, after which a clear topcoat has been applied thereover. The laser generates fragile product identification indicia on the workpiece by its beam being directed onto the basecoat for its blackening to generate the fragile product identification indicia by the selective charring of said basecoat. The clear topcoat seals the fragile product identification indicia. High temperature use of the label can be realized by using a siloxane or other high-temperature paint for both the basecoat and the topcoat.

Claims

1. A method for marking workpieces for identification thereof, which comprises the steps of:

(a) providing a laser that emits a beam comprising a select band of radiation;

(b) coating said workpiece with a coat of a basecoat which is a laser-blackenable paint;

(c) at least partially curing said basecoat;

(d) contacting said at least partially-cured basecoat with said laser beam to char said basecoat to form fragile product identification indicia thereon; and

(e) overcoating said basecoat with a coat of a clear topcoat;

whereby, said fragile product identification indicia are protected by said clear topcoat while permitting said product identification indicia to be seen.

2. The method of claim 1, wherein said product identification indicia are humanly or machine readable.

3. The method of claim 2, wherein said basecoat is provided to be white in color.

4. The method of claim 1, wherein said laser provided is a CO₂ laser.

5. The method of claim 4, wherein said CO₂ laser is a raster-scanning infrared laser beam emitting CO₂ laser that is raster-scanned in the Y-axis;

and said workpiece is moved in the X-axis for said laser beam to form said product identification indicia.

6. The method of claim 1, wherein said product identification indicia formed in said step (d) includes one or more of human readable and machine readable information formed from one or more of alphanumeric characters and graphic characters.

7. The method of claim 1, wherein the workpiece is a pipe having an inside diameter, which pipe is coated on said inside diameter in said steps (b) and (e).

8. The method of claim 1, wherein said laser in said step (d) is connected to a pair of galvanometer or stepper motor-driven mirror systems so as to scan in both the X-axis and the Y-axis.

9. The method of claim 1, which further includes the step of:

blowing air across the basecoat concomitant with or following said step (d) to carry away any soot particles which are produced by said laser beam contacting said basecoat.

10. The method of claim 1, which additional comprises the step of:

(f) curing said topcoat and, if necessary, said basecoat.