That's very troublesome. The accurate way is to shoot with a high-speed camera and observe the stroke (distance) of the needle retracted into the needle mouth after the machine loses magnetism. Larger distance means soft, and small distance means hard! "The best result is to use the least number of penetrations to feed enough color material into the target position. At this time, if you put aside the technique, the problem of the machine will appear. The skin damage caused by the fast and hard machine is large...The skin damage caused by the slow and soft machine is small. The reason is that the fast and hard machine has a short time when the needle is retracted into the needle tip during work. In addition, the front shrapnel is relatively hard, and the retractable stroke after the loss of magnetism is also small. The needle tip has a small amount of pigment dipping, and of course less can be sent to the target position. .... On the contrary, the slow and flexible machine in the work each time the needle is retracted into the needle nozzle for a long time, and the reason is that the front shrapnel is relatively soft. The stroke that can be retracted after loss of magnetism is also large, which is equivalent to increasing the amount of color material dipped in the needle tip, and more can be sent to the target position! Although I only did an experiment on the exercise skin --- 2 cross-sections of the exercise skin with basically the same color saturation were put under the microscope and my analysis above was verified. The experiment also included a tensile test on exercise skins of the same specification, and the results were the same."
