The principle and process of blow molding

Today’s Kunshan blow molding processing Zhida editor briefly introduces the basic working principle of blow molding processing for us

In the blow molding process, after the liquid plastic is sprayed out first, the plastic body is blown to the mold cavity of a certain shape by using the wind blown by the machine, and then the product is made. The plastic is melted and quantitatively extruded in the screw extruder, and then formed by the oral film, and then cooled by the air ring, and then pulled by the tractor at a certain speed, and the winder winds it into a roll.

The working process of a large blow molding machine:

The structure of the active air ring adopts the double air outlet method, during which the air volume of the inferior outlet is kept stable, and the upper air outlet is divided into several air ducts on the circumference. degree to control the air volume of each air duct. During the control process, the thickness signal detected by the thickness measuring probe is transmitted to the computer. The computer compares the thickness signal with the average thickness set at that time, and calculates according to the thickness error and the curve change trend, and controls the motor to drive the valve to move. When the thickness is thick, the motor moves forward and the air outlet closes; on the contrary, the motor moves in the reverse direction and the air outlet increases. By changing the air volume of each point on the circumference of the air ring, the cooling speed of each point is adjusted, so that the lateral thickness error of the film can be controlled at the target scale. .