![]() If the mold temperature is low and uniform, and the cooling speed is fast, the product will be transparent with little crystallization. If the mold temperature or the material temperature is not properly controlled, it is easy to cause “white mist” and non-transparency. The recycled material should not be too large, otherwise it will be easy to produce the “bridging” effect in the feeding area and thus affect plasticization. If it exceeds 15 minutes, cleaning with viscous PE is required, while lowering theīarrel temperature to PE temperature until the machine is turned on again.Ĩ. If the shutdown time is less than 15 minutes, only empty shot is needed To prevent the molecular weight from decreasing. Residence time: Do not keep the residence time too long, so as The backpressure is no more than 100bar, but unnecessary in most cases.ħ. Backpressure: the lower the better, so as to avoid wear. But if it is tooįast, the high shear rate will make the material brittle. To prevent premature solidification during injection molding. ![]() Injection speed: Usually, the injection speed should be fast enough Usually ranging between 270 and 295℃ and 290-315℃ for reinforced GF-PET.ĥ. Melt temperature: Able to be measured via the empty shot method, Overheating or cracking, but the depth of the vent usually does not exceedĠ.03mm, otherwise flashing is likely to occur.Ĥ. ![]() Venting must be sufficient to avoid local Mold and the machine plates, of which the thickness should stand at about 12mm Therefore, it is the best to design a heat insulator between the Mold and gate design: PET preforms are usually molded by hot Selected when the clamping force is higher than 6300t/m2.ģ. Small and medium-sized PET plasticizing systems in recent years, which are Based on these requirements, Hwamda has developed the special (including the recycled material) cannot be less than 2/3 of the injection Multi-stage temperature controller and less self-friction heat generationĭuring plasticization is required. Stable time after the high melting point. Selection of injection molding machine: PET has a very short Needs to be thoroughly dried, doesn’t exceed 25%.Ģ. Usually, the proportion of the recycled material that Empty shot can be performed to see whether the material Must be dried before injection molding, usually for more than 4 hours at 150☌,Īnd 3-4 hours at 170☌. Leading to discolored and brittle final products. When the water contentĮxceeds the limit, the molecular weight of PET decreases during processing, Lipid groups, it features a certain degree of hydrophilicity, and its pelletsĪre more sensitive to water at high temperatures. Treatment of the plastic: Since PET macromolecules contain Therefore, the former is mainly leveraged to change the fluidity of PET melt.ġ. Currently, GF-PET is the most popular variant among the clients.The rheology of the molten state PET is very good, while pressure has a greater influence on its viscosity than temperature. Polyethylene terephthalate (PET) is also known as polyester.
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