After a period of use, molybdenum wire will have a black spot, usually several to ten millimeters long, separated by several to dozens of centimeters. The black spots are caused by continuous arc discharge, after a period of combustion and carbonization. Thin, brittle, carbonized and prone to fracture. The black spot forms a single black spot on the silk tube, and sometimes it is arranged in a regular pattern to form a pattern. So how do we solve this? This article will introduce you.

Because the continuous arc discharge caused by ionization cannot be effectively eliminated, the resistance heat of arc precipitates a large number of carbon into carbon particles, resulting in molybdenum wire itself is also carbonized. The basic conditions for the pattern phenomenon are thick working parts (large discharge gap), low dielectric coefficient of water (poor insulation recovery ability), and DC component of pulse source with arc extinguishing time (greater than 10 mA). Therefore, once the pattern appears, it is necessary to start with these three elements: first confirm the quality of the pulse generator, if there is no DC element that blocks the arc, it will not cause broken wire. Secondly, we must pay attention to water, water is dirty and fine, less active ingredients; It contains a certain amount of salt, alkali and other components that hinder dielectric insulation. Pay attention to the material, even if there is the incentive of arc combustion, the exchange of water is fast, the removal of corrosion and impurities is easy, the instant "rush" in the past. Thick, easy to produce arc burn inducement, very difficult to discharge. Especially with black oxide skin, forging sandwich, raw materials without forging tempering and quenching, the probability of "silk" is very high. As long as one of the materials, silk and water, remains after being "chopped", the likelihood of being "chopped" again is high. So the relatively simple way is to change the silk, molybdenum wire, water, material. The pattern phenomenon is not the cause of the machine tool in many cases. After confirming that there are no problems with the pulse source and no abnormalities in the gap tracking, we turn to three basic conditions, one trigger. Simply adjusting the bed does not help solve the problem.