PET injection molding procedure is one among the most essential technologies for processing PET plastic bottles, and most plastic packaging plants will use blow molding manufacturing methods, but injection molding method has unique processing benefits. Many aspects must be considered by technical people while using PET for the injection molding such as PVC roofing company.
Introduction of PET plastics
Polyterephthalate alcohol ester, generally known as polyester, is the chemical name for PET. GF-PET is now the most popular among clients, mostly for bottle preformed. PET has better rheological properties in the melting stage, and the impact of pressure on viscosity is greater compared to that of temperature. As a result, the pressure has the greatest influence on the flow of melted material.
The glass conversion temperature for PET is 165°C, and the temperature range is 120-220°C. It is highly hygroscopic and bends easily. Crystalline reinforcing compounds can increase crystallinity. At lower mold temperatures, non-filled PET materials can produce transparent objects.
PET Injection Molding Process
The injection molding process is most commonly used to improve the molding for PET. In most cases, a screw kind injection machine is employed. Hardening the screw is frequently required to prevent wear after extended usage. The length for the injection machine's nozzle hole must be kept as low as feasible, and the diameter for the injection machine must be kept about 3mm.
The improved PET has a melting point for up to 260 °C. A bigger power heater must be added to prevent nozzle clogging. Furthermore, the tip in the nozzle hole seems ideally treated as a reverse cone, as illustrated in figure -1, to make it easier to cut off the molten substance in the channel of flow and the nozzle.
PET Molding Conditions:
1.Barrel Temperature
The temperature that occurs in the barrel has a direct impact on PET performance, with a temperature range of 240-280°C for fiber glass reinforced PET and 250-290°C with fiber glass reinforced PET. The temperature of the nozzles shouldn't go above 300 °C, and the temperature of the barrel should be maintained correspondingly.
2.Mold Temperature
The mold temperature provides a direct influence on the rate of cooling and crystallinity within the melt, with the crystallinity being varied, as are the qualities of the plastic components. Typically, this mold temperature is kept between 100 and 140°C. While forming thin-walled plastic components, it is preferable to have a small value; while forming thick-walled plastic parts, it is preferable to have a big value.
3.Injection Pressure
PET melts quickly under medium pressure, which is generally 80-140 MPa. Glass fiber reinforced PET needs injection pressures ranging from 90 to 150 MPa, depending on parameters such as gate size, filler type, plastic component form, mold temperature, as well as the PET injection molding type.
Tags: PVC roofing company, Plastic manufacturing, PET injection molding
