Ntroduction Of Screw Rotary Belt Operation In Plasticizing Of Nitriding Screw Barrel

ntroduction of Screw Rotary Belt Operation in Plasticizing of Nitriding Screw Barrel

In the production of Nitriding Screw Barrel, the main factors affecting the plasticizing quality are: length-diameter ratio, compression ratio, back pressure, screw speed, barrel heating temperature, etc. This article first introduces the back pressure and screw belt operation.

 

Back pressure

A. Increasing back pressure can increase the work done by screw on melting resin, eliminate unmelted plastic particles, and increase the density and uniformity of raw materials in the feeding tube.

B. Back pressure is used to increase the temperature of barrel, and its effect is the most remarkable.

C. Excessive back pressure makes it easy to decompose plastics with high thermal sensitivity, and may cause salivation for plastics with low viscosity. If the back pressure is too low, the finished products may have bubbles.

 

Screw speed

A. The rotating speed of the screw directly affects the shear of plastic in the spiral groove.

B. Small screw grooves absorb heat more quickly than shallow ones, which is enough to soften the plastic during compression. The friction heat energy between screw and barrel wall is lower, so they are suitable for high-speed rotation and increase plasticizing capacity.

C. Large screw should not rotate quickly to avoid uneven plasticization and excessive friction heat.

D. For plastics with high thermal sensitivity, if the screw speed is too high, the plastics will decompose easily.

E. Usually, screw of various sizes has a certain rotational speed range, the general rotational speed is 100 rpm; too low can not melt plastic, too high will burn plastic.