PET plastic bottle from the embryo to the molding need what conditions

1, PET hygroscopic than PBT, slightly large, aggregate at high temperature is more sensitive to water, when the moisture content exceeds bid, the hydrolysis processing happens, make a significant decline in the quality, therefore, before forming, must to dry raw materials. 2, the crystallinity of PET is smaller than PBT, butyl, vitamin E and packaging manufacturer with relatively higher molecular weight and lower, so the molding cycle is long, not like PBT, rapid prototyping. 3, PBT, molding shrinkage ratio is larger, general is 1. 8% glass fiber reinforced PET is 0. 2% ~ 1. 0%, the anti-embrittlement temperature plastics shrinkage rate, and low mold temperature shrinkage of small plastic parts. 4, PET products often residual internal stress, so often need post-processing after general shape. 5, when PET molding plus people back to the material should be sufficient for the dry and do not produce a thermal degradation, addition amount shall not exceed 20%. 6, the rheological properties of PET under molten is non-newtonian model, the influence of temperature on the viscosity of the melt is not big, can adjust the pressure to increase shear stress or shear rate. 7, there is apparent the melting point of PET, the processing temperature range is narrow, is 270 ~ 290 ℃, thermal degradation happens when more than 300 ℃. 8, PET molding pressure maintaining time cannot too long, otherwise it will increase the internal stress, usually for 20 ~ 50 s. 9, due to the fast curing PET melt, spices wholesale packaging so high speed injection should be adopted, in order to avoid the melt filled cavity as soon as possible. 10, PET and PBT, is sensitive to sharp corners, gaps, the place is easy to appear stress concentration, the bearing capacity decrease, prone to rupture when stress or shock, so the arc transition to these places should be adopted. 11, PET mold runner should reduce the melt pressure drop as far as possible, avoid using high melt temperature, flow channel is good with short and thick, surface area and the ratio of the cross-sectional area should be small, multi-purpose circular flow channel. 12, in avoiding liquid jet under the premise of PET gate should be opened in the plastic pieces of thick, can avoid the disadvantage of flow resistance and cooling fast, ensure its full of cavity. 13, PET gate opening position can good is core of cavity walls or bulky, it can change the flow direction, to reduce the flow velocity, the molten material can uniformly fill the cavity, to avoid surface defects. 14, PET is false when molten plastic.