Polycarbonate (PC) is an amorphous, odorless, non-toxic, highly transparent, colorless or yellowish thermoplastic engineering plastic. Most of hot runner nuzzle tips use BECU material for plastic injection molding.
However, if a certain amount of glass fiber (GF) is added to the PC material, the nuzzle tip will be easily worn. Once the nuzzle tip is worn, the tip will become larger and higher, and eventually the heat will not be conducted to the front section and lead to cold glue. At that time, the tip should be replaced but frequent replacement of the tip may cause a lot of troubles in production. Obviously, the wear resistance and the good thermal conductivity the nozzle material are important.
A small amount of titanium and zirconium can improve the dimensional stability of molybdenum at high temperature. The hot runner nozzles made of TZM alloy can greatly extend the service life and minimize tooling time and downtime. Solid solution hardening of molybdenum and titanium coupled with titanium-zirconium carbides improve the mechanical properties at high temperatures. This is very suitable for applications in high-temperature furnaces, but in contrast, plastic injection molding is performed at moderate temperatures. But TZM also has its advantages here. The nozzle material is subject to high levels of mechanical stress at temperatures of 400 °C.
Compared with other materials, TZM material has excellent thermal conductivity and corrosion resistance, which provides decisive advantages for the hot runner process. In addition, the hardness and tensile strength of the alloy are higher than those of pure molybdenum. This makes the material more elastic. It is also worth noted that many types of plastics contain extremely hard additives such as glass fibers or pigments. The wear resistance of TZM material will greatly reduce the damage when processing plastics containing highly abrasive components.
Chinatungsten is a professional manufacturer of tungsten and molybdenum for more than two decades. The TZM material provided by us would be helpful for the service life and work efficiency of hot runner systems.
