PBT is easily hydrolyzed at high temperatures, so drying prior to processing is important. It is recommended to dry in air at 120 ° C, 6 ~ 8 hours, or 150 ° C, 2 ~ 4 hours. The humidity must be less than 0.03%. If drying with a hygroscopic dryer, the recommended conditions are 150 ° C for 2.5 hours.
Melting temperature: 225~275°C, recommended temperature: 250°C.
Mold temperature: 40 to 60 ° C for unreinforced materials. The cooling channels of the mold are well designed to reduce the bending of the plastic parts. The loss of heat must be fast and even. It is recommended that the mold cooling channel has a diameter of 12 mm.
Injection pressure: medium (up to 1500 bar).
Injection speed: The injection speed should be as fast as possible (because PBT solidifies quickly).
Runners and gates: Round runners are recommended to increase pressure transfer (empirical formula: runner diameter = plastic thickness + 1.5mm). Various types of gates can be used. Hot runners can also be used, but care should be taken to prevent leakage and degradation of the material. The gate diameter should be between 0.8 and 1.0*t, where t is the thickness of the plastic part. If it is a submerged gate, the recommended minimum diameter is 0.75mm.
