The principle and process of blow molding processing

Today, the editor of Juxinchang blow molding factory will briefly introduce the basic working principle of blow molding processing for everyone

Blow molding process first sprays out liquid plastic, and then uses the wind force blown out by the machine to attach the plastic body to a certain shape of the mold cavity, thus making the product. Plastic is melted and quantitatively extruded in a screw extruder, then molded through a mouth film, cooled by an air ring, and then pulled by a traction machine at a certain speed, and wound into a roll by a winding machine.

The working process of a large blow molding machine:

The automatic air ring structure adopts a dual air outlet method, where the air volume at the lower air outlet remains constant, and the upper air outlet is divided into several air ducts on the circumference. Each air duct is composed of an air chamber, a valve, a motor, etc. The motor drives the valve to adjust the opening degree of the air duct and control the air volume of each air duct. During the control process, the thickness probe detects the thickness signal of the thin film and transmits it to the computer. The computer compares the thickness signal with the current set average thickness and performs calculations based on the thickness deviation and curve trend. It controls the motor to drive the valve to move. When the thin film is too thick, the motor moves forward and the air outlet closes; On the contrary, the motor moves in the opposite direction, and the air outlet increases. By changing the air volume at each point on the circumference of the air ring and adjusting the cooling speed at each point, the lateral thickness deviation of the film is controlled within the target range.