Cutting Process Presumed from Cut Section by Hairdressing Scissors

Abstract

Japanese hairdressing scissors are highly regarded around the world. However, the cutting process is unknown. In this study, we attempted to clarify this process by observing the cross sections of a copper wire after cutting. We found that there are three different surfaces on the cross section. The first surface is made by the inside of the scissors blade edge. The second surface is located opposite to the first one. This surface is created by another side of the blade edge that forms the first surface. The third surface created by shear fracture exists between these two surfaces. During cutting, the cutting position is closer to the tip of the blade than the point where blades touch each other. Therefore, there is a crossover distance K between the tips of two edges. If K is sufficiently large, cutting will be completed. When cutting conditions become more stringent, two blades are pushed apart during cutting. At this time, if K becomes very small, cutting will not be completed. Thus, K is important for cutting. Moreover, we showed the relationship between the cutting position and K, and presented a calculation method.