Die three-layer co-extrusion film blower cover from top to bottom, that is, when thick, loosen the screw. (Thick side tightens hard). This is called the forward die. If there is a big mouth below and the top die is put in, it is to loosen the thin side and tighten the thick side. This is called reverse adjustment.
There are four or six adjusting bolts in the die head, which are usually hexagonal. At the upper edge of the die, they can be adjusted. As for the tightness or looseness, different moulds from different origins are different, it is necessary to know after operation. For LDPE film, it is better to control the ratio of bubble diameter to die diameter by checking the die diameter, tube folding diameter and blowing ratio.
Blow ratio - ratio of diameters of film tube to nose - r = H / R b, i.e. r = H / delta B R - blown degree Delta - thickness of film H - gap of die B - is drawing speed folding width = D/2. The main structure of film blower is mainly composed of extruder, die, die, cooling device, foam stabilizer, herringbone plate, drawing roller, coiling device and so on. 1: Extruder, extruder is mainly composed of screw, barrel feeder, deceleration and drive. Composition of motor.
The drive motor adopts electromagnetic speed regulating motor (or frequency conversion common motor), which drives the screw to rotate in the barrel by belt drive, and makes the plastic particles melted in the hopper under external heating extrude 2:3 through three filters from the die mouth, which consists of three parts: filter screen, filter plate and three-way pressure cover.