Studies on the theory of single screw plasticating extrusion. Part I: A new experimental method for extrusion
An extruder specially designed for the study of the single-screw plasticating extrusion process was constructed. Its barrel is equipped with glass windows which are located on both sides of it so that the full process of plasticating extrusion, solid conveying, melting, and melt conveying, can be clearly observed and recorded with photos and video recordings through the transparent windows. The solid profile X/W, the velocity of the solid bed Vsz, the forming positions of the upper melt film and the melt pool, and the position at which the break-up of solid bed occurs, was easily determined with good accuracy. Many dynamic characters of the plasticating extrusion, such as the non-plug solid conveying, the process of the break-up of the solid bed and the disappearance of the, broken pieces of solid, were also observed in the experiments.
This paper discusses the project-based teaching design of Stamping Mold Design and Manufacturing in higher vocational education.The teaching is based on the typical task in real working environment,emphasizes the interaction between the teachers and the students,pays attention to the teacher's leading function and the student's participation.Teachers should construct the teaching contents according to the logic relation of work process,and put forward an open and whole assessment system.