Razor Blade and Method of Manufacture
A method for making a razor blade having a bent portion is disclosed. The method includes: providing an elongated strip of stainless steel that can be 0.076 mm thick; hardening the strip; providing a cutting edge along an edge of the strip and providing coating(s) on the cutting edge. The stainless steel has a carbon content preferably between 0.45% and 0.55% by weight. The strip is separated lengthwise into discrete razor blades. The bent portion of the razor blade is then formed using a swivel bending process. When the razor blade is bent to define an included angle of 90 degrees between planar regions adjacent the bent portion and an inner surface having a radius about 0.3-0.35 mm, the outer surface of the bent portion is free from macro-cracks.
1 . A method of making a razor blade having a bent portion, comprising the steps of:
a) providing an elongated strip of stainless steel having a front edge portion and a back edge portion, the stainless steel having a carbon content less than 0.60% by weight;
b) hardening the strip to a first hardness;
c) providing a cutting edge extending along the front edge portion of the elongated strip;
d) cutting a lengthwise extending portion from the strip, the lengthwise extending portion providing a discrete razor blade having a length suitable for use in a razor cartridge housing, each discrete razor blade including a cutting edge, a back edge portion and a body portion therebetween; and
e) forming a region of the body portion by swivel bending to provide the bent portion in the body portion;
wherein the razor blade thus formed includes a first generally planar portion between the cutting edge and the bent portion and a second generally planar portion between the bent portion and the back edge portion.
2 . The method of claim 1 , wherein the process further includes a step of perforating one or more apertures.
3 . The method of claim 2 , wherein the step of perforation occurs before step e) and after step d).
4 . The method of claim 1 , wherein the carbon content is between 0.45% and 0.55% carbon by weight.
5 . The method of claim 1 , wherein the stainless steel further includes between 1.0 and 1.6% molybdenum by weight.
6 . The method of claim 1 , wherein the first hardness is in the range 660 HV to 850 HV.
7 . The method of claim 1 , wherein the method further includes the step of annealing at least a portion of the strip containing the cutting edge to reduce the hardness of the portion of the strip containing the cutting edge to a second hardness of at least 600 HV.
8 . The method of claim 1 , wherein step d) occurs during a curing process for a PTFE coating applied to the cutting edge.
9 . The method of claim 1 , wherein, when the razor blade is formed such that the first planar portion is generally perpendicular to the second planar portion, an outer surface of the bent portion is free from macro-cracks having a depth more than ⅔ the thickness of the strip.
10 .- 15 . (canceled)