CPP casting machine production line, the production process of cast film

Cast film production equipment includes extruders, magnetic heads, air knives, chill rolls, corona treatment rolls, draw rolls, take-up devices, trimming and recycling systems. This article mainly introduces three types of extruder, die head and cooling roll.
CPP casting machine production line CPP casting machine manufacturers
The cast CPP film production process is divided into 11 stages
Resin - extrusion melt plasticization - t-head extrusion - casting - cooling roll setting - corona treatment - traction - coiling - storage natural shrinkage - segmentation - finished product.
Compressed air blows the cast film onto the surface of the cooling roll, and the cooling roll is tightened to improve the cooling effect. Both sides of the film are further cooled by two cold rollers. The cast film has sufficient cooling, so the production speed is 60 ~ 100m/min higher than the injection molding method, and may be 3 ~ 4 times the production speed of the blown film.
Cast film production equipment mainly includes extruders, magnetic heads, air knives, cooling rolls, corona treatment rolls, pulling rolls, coiling devices, trimming and recycling systems.
CPP casting machine production line CPP casting machine manufacturers
Three major production equipment for cast film
1. Extruder
Cast films typically use single screw extruders. Polypropylene screw, diameter 90~200mm, l/d=25~33, =3.5~4, including possible mutation of mixing head; screw for polyethylene, diameter 90~150mm, L/D=25~28, =3.0, the structure is measured.
2. Machine head
Polypropylene cast film heads can be branch pipes or coat hangers. Head widths are available in various sizes: 1.3m, 2.4m, 3.3m and 4.2m. The length of the flat part of the concave die is L=(50~80)t (t is the thickness of the film), and the time for the thickness of the film is the largest value; the mold opening of the concave mold is 0.3 to 0.5mm, and the small value is when the thickness is large. Polyamide cast film mainly uses support tube head, and the length of die lip must be slightly longer than CPP. The polyethylene casting film mainly adopts the branch pipe structure, the branch diameter is 30~50mm, and the distance between the die ribs is 0.3~1.0mm.
3. Cooling roller
Polyethylene and CPP cast film cooling rolls are large steel rolls with a diameter of 400~1000mm, and the head width is larger, whichever is larger. The drum surface is hard chrome plated and ground on mirror cleanliness. The rollers are double helical cooling tubes cooled by coolant. The double-sided cooling roll has two films for further cooling both surfaces, and its diameter is smaller than that of the cooling roll, with a diameter of 150~300mm. The surface is the same as the cast chill roll.
Polyamide casting film cooling is different from CPP film. It is divided into two steps of cooling. The casting roll is an oil cooling roll, and the heat transfer oil is passed through the roll. The temperature of the hot roll is 90 ~ 100 ℃, which is lower than the casting film temperature. The rolls are then cooled with water, which cools the film to room temperature.
CPP casting machine production line CPP casting machine manufacturers