Extruder is one of the types of plastic machinery, which originated in the 18th century. The extruder can divide the head into right angle head and oblique angle head according to the material flow direction of the head and the included angle of the screw centerline.
Classification of feeding methods of extruder.
① Gravity feeding:
Principle - materials enter the barrel by their own weight, including manual feeding, spring feeding and blast feeding.
Features - simple structure and low cost. However, it is easy to cause uneven feeding, which affects the quality of parts. It is only suitable for small size extruders.
② Forced feeding:
Principle - a device that can exert external pressure on the material is installed in the hopper to force the material into the barrel of the extruder.
Features - it can overcome the phenomenon of "bridging" and make the feeding uniform. The feeding screw is driven by the extruder screw through the transmission chain to adapt its speed to the screw speed. The overload protection device can be started when the feeding port is blocked, so as to avoid the damage of the feeding device.