Extrusion blowing process
The extrusion blowing process is as follows
The first part is divided into 5 parts
Rod (diameter 6cm), shell 8, 7cm, 11kw motor (host) drive. Starting from the feed inlet, it is divided into 1, 2 and 3 heating zones.
Next, turning upward, it belongs to four heating zones. The parts are called three links, one for three zones, two for network outlet, and three for five zones.
The fifth heating area, that is, the discharge area, turns from flat to up through three ports, which is called film head, which is the most critical part of the machine. The accessory is a blower.
The second part is traction area
The total height is about 3 or 5 meters. The accessories are air pump.
The third part is the winding area
Main material: low pressure polyethylene hPPE
With high-pressure polyethylene LLDPE mixture, the low-pressure material mainly accounts for about 80%. The more high-pressure is added, the better the tension is. The disadvantage is that there is no stiffness. Too much blowing will cause the blown film to swing back and forth, and the blown film edge is not neat, and even can not be blown at last.
Start blowing process:
First, it is preheated in the first, second and third zones. The first zone is lower, generally about 170 ℃, and the other several zones are about 200 ℃. If the temperature is high, the material can not be sent from the screw, and even burnt and discolored.
Then there are four districts, namely, three links. A 60 mesh-160 filter screen is placed in the tee to prevent impurities from entering zone 5. The larger the mesh size, the finer the mesh is, the thinner the membrane with higher requirements can be blown, including the transparency of the membrane, hand sensitivity, smoothness, tension, etc., but too much and too fine will prevent the material from passing through, and too much will not blow out. Generally, 3-5 pieces are suitable, and the thickness will be determined according to the requirements.