WEDM is carried out in the working fluid medium. The insulation performance of the working fluid plays a role of deionization in the process of pulse discharge, accelerating the cooling of electrodes and workpieces in the process of machining, and making the corrosion products suspended and discharged from the discharge gap. The quality of working fluid will have a great influence on cutting speed, surface roughness and machining accuracy. As a low-speed wire cutting process with high-precision parts, it naturally has higher requirements on the quality of working fluid, which requires deionized water to have lower conductivity (generally, the conductivity is less than 20μs/cm).

In the ultra-pure water preparation and polishing process, high-quality polishing resins with higher processing accuracy, higher purity level and uniform particle size are needed to achieve the purification of water. Sunresin have developed the "jet granulation" technology and uses the world's leading resin production line produced high-purity, high-transformation, uniform-grain H-type cation exchange resin and OH-type anion exchange resin with uniformity coefficient <1.1, which were pre-mixed in a certain proportion and used for the refining treatment at the end of ultrapure water preparation system. (Refined polishing process section)

Ion exchange is one of the most commonly used water treatment technologies.

Water treatment resins are classified into cationic resins and anionic resins. Cationic resins are subdivided into sodium and hydrogen resins. Sodium resins exchange calcium and magnesium ions into sodium ions, which soften water.

1. Problems caused by hard water. The demand for softening water technology begins with boiler water.

1. Arsenic in groundwater Arsenic is a common source of pollution in drinking water in nature, from arsenic-containing rocks, soils, etc., and then slowly diffuses into the water. Arsenic is often present in both organic and inorganic arsenic forms, whereas inorganic arsenic is more prevalent in water and more toxic. The countries with serious arsenic pollution in groundwater are India, Bangladesh, Vietnam, Argentina, Chile, Mexico, China, and Hungary. In China's Taiwan, Xinjiang and Inner Mongolia, local groundwater contains up to 2000ug/L of arsenic. At present, the World Health Organization stipulates that arsenic in drinking water should not exceed 10 ppb.