Machines can be used to make swords, and molds can be mass-produced with punches of CNC machine tools. However, a series of tools such as the handle and scabbard need to be assembled by hand, and the dimensional accuracy of the machine will definitely be better than that by hand. Nowadays, hand-made knives are usually cut with heat-treated materials and then made, or like the Japanese knife-making method mentioned by the man just now, or the folding forging technology of Longquan, the knives made are generally time-consuming and laborious, so they are expensive. As you said, cheap martial arts knives are basically no different from iron pieces, except that iron pieces similar to knives are equipped with a pair, so they are cheaper. It's cheaper to do it by hand than by machine, because it's quite simple. Just grind the shape directly. So use your hands.