First, the plastic foam ball diameter tolerance standard is based on the international general GD-ELK003, diameter tolerance divided into five grades according to level, respectively, the roundness, weight, surface finish, the maximum batch tolerance and batch tolerances are strict Grades of plastic foam ball at home and abroad are G0-standard foam plastic ball, G1 foam plastic ball, G2 plastic foam ball, G3-class plastic foam ball, G4 foam plastic ball. G0-class plastic foam ball diameter tolerance is limited to ± 0.001, roundness of 0.002mm. G1-class plastic foam ball diameter tolerance is limited to ± 0.002, roundness 0.003mm. G2-class plastic foam ball diameter tolerance is limited to ± 0.005, roundness 0.006mm. G3 grade plastic foam ball diameter tolerance is limited to ± 0.01, roundness of 0.015mm. G4 grade plastic foam ball diameter tolerance is limited to ± 0.05, true roundness 0.07mm. Second, the production process of plastic foam ball process: 1, the first to buy plastic foaming agent, different plastics will use different blowing agents, plastic raw materials and foaming agent in the mixer to fully mix, and then put Drying is carried out in a drying machine. 2, the injection molding machine gun mouth to have automatic locking device, because the foam plastic ball forming a cycle, the nozzle will flow glue, can not complete the next injection, but also a waste of material. 3, forming my bubble plastic ball is also connected to the outlet, the conventional practice is to use the pliers to cut off the nozzle, foam plastic ball diameter ball diameter tolerance is difficult to control, because the plastic foam process, temperature, injection pressure The size of the ball has an impact. 4, the molding of the plastic foam ball rough, grinding, grinding machine through the grinding ball after the foam plastic ball only accuracy. 5, foam plastic ball polishing process is more complex, because the surface of foam plastic ball relatively rough, and flexible, very good row of polishing, the general polishing time should be more than 5 hours. 6, foam plastic ball inspection is mainly measured diameter tolerances, surface finish, there is a detection of weight.