Plastic Bottle Manufacturing Machine

Plastic Bottle Cap Manufacturer, Custom Pet Bottles, Pet Bottles suppliers.
Made by:  http://www.plastic-bottle-manufacturers.com 
The ratio of the height of its neck PET bottle thread diameter of the mandrel can be determined parison aspect ratio (L / D)
Mandrel aspect ratio generally ranging principle is no more than 10: 1. This is because the parison mold mandrel as a cantilever, and by the effect of high injection pressure during filling. Selected aspect ratio is larger, its larger mandrel bent, likely to cause the parison wall thickness distribution is uneven. However, through the program to control the melt filling speed or filling process using a sliding thimble temporarily secured to the mandrel head end of the mandrel, the mandrel diameter ratio advisable at this great value. Parison reference height is the height of the bottle body height obtained by multiplying the coefficient, the height of the bottle is generally 92% to 95%. In order to ensure good transparency of the bottle, a melt parison mold after filling, the temperature was quickly lowered to less 145 ℃, but than the glass transition temperature of the polyester material (82 ℃) higher and closer to the glass temperature, the higher the transparency of blown bottles. Parison mold cooling water temperature up to 10 ℃ ~ 35 ℃, for rapid cooling of the parison, it will take a liquid or gas to the mandrel continuous cooling, where cool air mandrel can have a more uniform temperature distribution, the air pressure is generally about 1MPa.
2, the melt temperature of the preform during injection
????The melt temperature is an important parameter PET preform molding to note. From the viewpoint of equipment, screw design have a greater impact on the PET melt, mix and melt temperature. PET injection to the use of low shear, low compression ratio (about 2/1) of the screw, made longer feed section, a transition section and a metering section made shorter. Barrel temperature of the device a greater impact on the melt temperature, barrel temperature increase will reduce the intrinsic viscosity of the PET melt. Barrel temperature had a significant effect on the parison transparency, improve cylinder temperature can improve the transparency of the parison. For example, when a barrel temperature of 280 ℃, the corresponding melt temperature of 290 ℃, can ensure optimal transparency parison. The barrel temperature increase does not improve further transparency. Lower barrel temperatures, an appropriate increase in screw speed to clap gate temperature, small quantities can improve the transparency of the parison. However, due to the hot runner system melt through time is short, to a lesser extent the temperature of the parison transparency improvement. Increase the injection pressure, i.e., when the injection rate, the heat generated when high shear melt through the nozzle, the melt temperature is significantly improved, so that the barrel temperature can be lower transparent molded parison. Higher packing pressure will increase the rate of crystallization when cooling the melt parison mold, reducing the transparency of the parison, especially at lower cylinder temperature.