A team of engineers at the Massachusetts Institute of technology (MIT) headed by K. Jam Tasana figured out why the steel blades of the razor blades while shaving, despite the fact that they’re 50 times tougher hair. With an electron microscope they found that under certain conditions, even one hair is capable of chipping the edge of the blade.
According to researchers, we are not talking about ordinary wear and tear of the metal, as in the case of friction, for example, on a whetstone. This process looks much more complicated. Metal razor with frequent “irregular” contact with the hairs is experiencing stress, which leads to the formation of cracks and chips, i.e. the wear of the cutting edge (blunting).
To learn more about what is happening during the shaving process, MIT graduate student Gianluca Roscioli shaved with a disposable blade, and then examined its surface under an electron microscope. As a result, he found a slight, but visible wear, and the chips were along the edge of the blade.
For more complex test Roscioli constructed micromechanical device consisting of a movable block and two clamps to hold the blade and a fixation test hairs of different diameters, provided his colleagues specifically for experiments. During the experiments the device was cut at different depths and at different angles, while being in the field of view of the electron microscope.
The analysis showed that the blades were not split off when I cut the hairs are perpendicular. However, everything changed when the cuts were made at an angle – the number of chips increased. Computer modelling showed that it is important not only the inclination but also the density of the steel in the blade.
With the aim of improving the quality of the blades, the researchers have filed a patent application that allows you to make razor steel more homogeneous.