Phenolic resin is the most commonly used plastic ball billiards, but the pool of phenolic resin material and pure barium sulfate filled plus a certain percentage of the purpose is to increase the weight to the plastic pool, phenolic resin plastic ball and a function is on top of the track ball, general medical equipment such as ultrasound machine. Above, X machine will use phenolic resin plastic ball, track ball and ship will be used for the above resin plastic ball, the characteristics of phenolic resin is of high hardness, smooth surface, machining process belongs to the casting process, the precision of plastic track ball is mainly determined by the mold, the mold to do good plastic track Zhuhai precision is high, the normal tolerances can be + 0.03mm, other than the plastic ball production process accuracy is slightly worse. Because the plastic injection molding process to increase the production of a grinding process, you can do more accurate.