Automated control of razor blade colorization

Abstract

Methods of and systems for automated color control are provided. These methods and systems are suitable for use in various oxidation processes for the coloration of heat treated steel, for example razor blade steel. A feedback loop (closed loop control) is established, including the steps of measuring color, comparing the measured color to a target color and quantifying the difference there-between, and, if the difference exceeds a predetermined threshold, adjusting a color adjustment parameter, e.g., the airflow to the oxidation zone, so that the measured and target colors are equivalent or within a predetermined variance.

1 . A process for manufacturing a razor blade comprising: 
 an automated feedback loop, measuring a color parameter of a blade steel strip exiting a coloration process, comparing the measured color to a target color and quantifying the difference there-between, and, if the difference exceeds a predetermined threshold, adjusting a color adjustment parameter so that the measured and target colors are equivalent or within a predetermined variance.    
   
   
       2 . The process of  claim 1  wherein the coloration process includes passing the steel strip through an oxidation zone, and the color adjustment parameter comprises air flow rate in the oxidation zone.  
   
   
       3 . The process of  claim 1  wherein the measuring step comprises measuring the reflection spectrum of the blade steel.  
   
   
       4 . The process of  claim 3  wherein the color parameter is the maximum or minimum value of the reflection spectrum.  
   
   
       5 . The process of  claim 3  wherein the measuring step is performed using a spectrometer.  
   
   
       6 . The process of  claim 2  wherein the adjusting step comprises using a mass flow controller to adjust the air flow.  
   
   
       7 . The process of  claim 1  wherein the coloration process comprises a thermal oxidation process or a reduction/re-oxidation process.  
   
   
       8 . The process of  claim 7  wherein the thermal oxidation process or reduction/re-oxidation process are part of the steel hardening process.  
   
   
       9 . The process of  claim 1  wherein the quantification of the difference is performed by a processor.  
   
   
       10 . A system for automated control of razor blade color comprising: 
 a spectrometer configured to measure the reflection spectrum from the blade steel as it exits the colorization process,    a controller configured to adjust a parameter of the colorization process,    a processor configured to determine a parameter associated with the measured reflection spectrum, calculate the difference between the measured parameter and a predetermined target value, and, if the difference is above a predetermined threshold, send a voltage to the mass flow controller, and    a hardening furnace equipped with an oxidation zone.    
   
   
       11 . The system of  claim 10  wherein the parameter is the wavelength of the minimum reflected light (λhd min) or maximum reflected light λ max ) of the reflection spectrum or higher order minimums or maximums.  
   
   
       12 . The system of  claim 10  wherein the controller includes a mass flow controller configured to either increase or decrease the flow of oxidizing gas to the oxidation zone, such that the target value is approached.  
   
   
       13 . The system of  claim 11  wherein the oxidizing gas comprises clean, dry air.  
   
   
       14 . The system of  claim 11  wherein the oxidizing gas is mixed with an inert carrier gas to decrease system response time.