Method and system for using an irreversible thermo-chromatic indicator for quality assurance of a part subjected to heat treating

Patent metadata

Field	Value
Publication number	US-9567660-B2
Application number	US-201313928580-A
Country	US
Kind code	B2
Filing date	Jun 27, 2013
Priority date	Jun 27, 2013
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

A system and method of verifying that a part is heat treated to strengthen the part. The part is marked with a thermo-chromatic composition before heat treating. The part is then heat treated to strengthen the part and change the color of the thermo-chromatic composition to indicate successful completion of the heat treating process. A detector may act to prevent the inclusion of a non-heat treated part in an assembly by disabling an assembly tool. A controller may also provide data related to the completion of the heat treating process to be recorded in a database.

First claim

What is claimed is:

1. A method of manufacturing a part that is strengthened by heat treating, comprising:
forming the part in one of the following metal forming processes:
stamping in a sheet metal forming process,
extruding,
forging, and
hydro-forming;

marking the part in a predetermined location with an irreversible thermo-chromatic composition;
heating the part to increase the strength of the part and to change the irreversible thermo-chromatic composition from a first color to a second color;
detecting whether the thermo-chromatic composition is the first color or the second color after the heating step; and
controlling a subsequent manufacturing process based upon whether the thermo-chromatic composition is the first color or the second color.

2. The method of claim 1 wherein the thermo-chromatic composition is an irreversible thermo-chromatic ink that has a first color that is white and a second color that is a darker color.

3. The method of claim 1 wherein the step of marking the part is performed by spraying the part in a location that is visible during the detecting step.

4. The method of claim 1 wherein the step of heating the part is performed by exposing the part to convective air at 170° C.-240° C. for more than 20 minutes.

5. The method of claim 1 wherein the step of detecting whether the irreversible thermo-chromatic composition is the first color or the second color further comprises optically sensing the thermo-chromatic composition with a machine vision detector that provides a signal to a controller of a manufacturing tool that operates on the part after the heating step, wherein if the thermo-chromatic composition is the first color, or if the thermo-chromatic composition is not the second color, or if the thermo-chromatic composition is not detected, the manufacturing tool is prevented from operating.

6. The method of claim 5 wherein the manufacturing tool is a weld tool.

7. The method of claim 5 wherein the manufacturing tool is a riveter.

8. The method of claim 5 wherein the manufacturing tool is a clinch tool.

9. The method of claim 5 wherein the manufacturing tool is a flow drill screwing tool.

10. The method of claim 5 wherein the manufacturing tool is a material handling tool.

11. The method of claim 1 wherein the step of detecting whether the thermo-chromatic composition is the first color or the second color further comprises optically sensing the color of the thermo-chromatic composition with a machine vision detector that provides a signal to a data storage system that correlates the signal to a part identification record associated with the part and records that the thermo-chromatic composition changed from the first color to the second color during the heating step or records that it did not change color.

12. A method of heat treating a part, comprising:
forming the part by stamping, extruding, forging or hydro-forming;
marking the part with an irreversible thermo-chromatic composition;
heating treating the part and changing the thermo-chromatic composition from a first color to a second color;
detecting the first color or the second color; and
controlling a subsequent manufacturing process based upon whether the thermo-chromatic composition is the first color or the second color.

Assignees

• Ford Global Tech Llc

Inventors

• Campbell Aindrea Mckelvey
• Freis Amanda Kay
• Friedman Peter A
• Nuno Rosa Lynda
• Luckey Jr S George

Classifications

• C21D1/68

  Temporary coatings or embedding materials applied before or during heat treatment · CPC title

• C21D11/00

  Process control or regulation for heat treatments · CPC title

• C22F1/04 Primary

  of aluminium or alloys based thereon · CPC title

• G01K11/12

  using changes in colour, translucency or reflectance · CPC title