Introduction to the fluidity of the bottle capping machine
The fluidity of the capping machine 1. Flowability 1.1 The fluidity of thermoplastics, generally from molecular weight, melt index, Archimedes spiral flow length, apparent viscosity and flow ratio (flow length / plastic wall) Thick) and other series of indices for analysis. Low molecular weight, wide molecular weight distribution, poor molecular structure, high melt index, long snail flow length, low viscosity, and good flow ratio. For injection molding.
According to the mold design requirements, the fluidity of common plastics can be roughly divided into three categories: 1 good fluidity, nylon, polyethylene, polystyrene, polypropylene, cellulose acetate, poly(4) methyl decene; 2 medium mobility Polystyrene series resin (such as ABS, AS), plexiglass, polyoxymethylene, polyphenylene ether; 3 poor flowability polycarbonate, hard polyvinyl chloride, polyphenylene ether, polysulfone, polyaryl sulfone, fluoroplastic. 2.2 The fluidity of various plastics also changes due to various molding factors. The main factors affecting the following are as follows: 1 The temperature of the material is high, the fluidity is increased, but different plastics are also different, polystyrene (especially impact resistant) The fluidity of plastics such as polypropylene, nylon, plexiglass, modified polystyrene (such as ABS, AS), polycarbonate, cellulose acetate, etc., varies greatly with temperature. For polyethylene and polyoxymethylene, the temperature increase and decrease has little effect on the fluidity. Therefore, the former should adjust the temperature to control the fluidity during molding. 2 When the pressure injection pressure is increased, the molten material is subjected to large shearing action and the fluidity is also increased. In particular, polyethylene and polyoxymethylene are sensitive, so the injection pressure should be adjusted to control the fluidity during molding. 3 mold structure casting system form, size, layout, cooling system design, melt flow resistance (such as profile finish, channel section thickness, cavity shape, exhaust system) and other factors directly affect the melt in the cavity The actual fluidity within the liquidity is reduced when the melt is lowered in temperature and the fluidity resistance is increased.
The mold should be designed according to the fluidity of the plastic used, and a reasonable structure should be selected. When molding, it can also control the material temperature, mold temperature and injection pressure, injection speed and other factors to properly adjust the filling to meet the molding needs.