The true genius of the double edged razor blade is how it is bent over and held in tension within the razor. This simple engineering technique allows the blade edge to be held very firmly in a precise position whilst using the minimum amount of steel in that blade. Hence double edged blades can be extremely thin and a thousand of them only weigh a few ounces. However this is still a massive amount of steel compared to multibladed system razors that only have an edge about 1mm deep made of steel which is then mounted in plastic.
Double edged blades have been in manufacture for over 100 years (though it was only in the 1930s that they became as thin as they are today) so their production is not rocket science. However putting a superb edge (for that is what is needed) on such a thin piece of steel in a mass manufacturing process is not easy.
Most of the world’s razors are made in a very small handful of factories around the world such as Gillette in Manuas, Brazil and St Petersburg, Russia, Vidyut in Bombay, India and Lord in Alexandria, Egypt. The manufacturing processes are proprietary and partly secret. The plants are capital intensive, contain a lot of technology and run at very high speed. The above video shows the processes (if you don’t blink!) and I will try and explain them.
Now for a disclaimer. This is not an academic paper and I am not a manufacturing engineer, this is just a blog article that looks at some of the processes involved. Factories will have more and different processes and will carry them out in different sequences. Also no razor factories changed hands in the writing of this article.
The process starts with drawing blade strips, the width of an individual blade, from large spools of steel. This steel is always a compromise between cost, the ability to take an edge, the ability to keep that edge, corrosion resistance and behaviour under heat treatment, plus a number of other factors. Stainless blade steel is a martensitic stainless steel with a composition of chromium of between 12 and 14.5% and a carbon content of approximately 0.6%. For a lot of the developing world cheaper carbon steel is often used.
The steel strips are like a long belt and go through a high speed punching machine to create the blade blanks, this removes the complex centre shape of the blade and the four locators in the corners, a job which requires great precision yet which a machine can do a thousand times or more in a minute. So one production line makes ten years supply of blades for an individual in 60 seconds.
The belt of blanks then go through a hardening and tempering process that involves heating and cooling the steel down repeatedly as it passes through furnaces. This is a tricky process if such thin steel is not to distort as it is subject to the temperature changes.
Next the belt of blanks goes through an etching machine to put the brand on each blade and a varnishing process to protect the blade from corrosion before the belt is broken up into individual blades.
Each blade then needs to have its edges ground by progressively finer grinding wheels, then polished and finally honed. The honing, which produces the final super sharp edge is done with animal leather. The edges then go through a vapour deposition coating/metal spray/sputtering process that adds a few molecules of titanium nitride, platinum or whatever proprietary cocktail to enhance its qualities. There are secrets here.
The finished blades then go through QA, which is why they often have the numbers 1 to 4 on them, it identifies which particular machine may be at fault if there is a problem. At this stage blades might be graded into different brands. The blades are then boiled and dried to clean and disinfect them before being packed.
It is amazing that all this work and technology results in blades that cost as little as $1 per 100, such is the sheer scale of the process.
Multibladed system razor cartridge blades are made in a similar process but are scored part way through just after the punching machine process, thus allowing the edges to be snapped off later down the production line and for the bulk of the steel to be recycled.