Plastic hollow ball is the most commonly used blow molding process, that is, to melt the plastic material into a certain proportion of plastic ball mold, and then use a fine metal needle to melt the plastic blowing, blowing the entire cavity, Plastic hollow ball is also completed production, open mold is out of finished products, velvet technology refers to the use of PVC powder plus plasticizer into a paste, and then into the dough ball mold, cover the mold, into the boring Rubber furnace heating, after a certain period of time after the high temperature, the inside of the paste into a solid, Tang plastic ball will be completed, welding process of ultrasonic welding is to put the two hemispheres buckle together, placed under the ultrasonic Ultrasonic welding, the disadvantage is the strength is not high, easy to seal lax, hot welding is the two hemispheres on a heating plate heating, hemispherical edge melting, remove the heating plate, the two hemispheres together, is good Plastic ball, the disadvantage is that the welding position will have a lot of approval of the wind.