4. feed extrusion is to act as a coolant motor energy - sometimes heater - transferred to the cold plastic, thereby converting it from a solid to melt. Input feed ratio in the feed zone of the screw cylinder and the surface temperature is low. However, the feed zone of the cylinder surface is almost always above the melting range of the plastic. It is the feed particles through contact with cooled, but the heat transfer heat from the hot front end and a back control of the heating is maintained. Even the current end of the heat retained by the viscous friction and heat input when the cylinder is not required, you may need after opening heater. The most important exception is slotted into the barrel, almost exclusively for HDPE. Screw the root surface is also cooled and plastic feed feed grains (and air between the particles) from the cylinder wall insulation. If the screw is stopped abruptly, the feed is stopped, and moved backward because the heat from the hotter front surface becomes hotter in the screw feed zone. This may cause adhesion of the particles or the root bridge. 5 in the feed zone, from sticking to the barrel of the screw in order to slide on a single-screw extruder feed zone of the barrel is smooth particle transport to reach the maximum amount of solid particles should be glued to the barrel and onto the screw on. If the particles stick to the screw root, nothing can pull them down; entrance channel volume and the amount of solids is reduced. Another reason is that at the root of poor adhesion of plastic may soak in here and produce gels and similar pollution particles, or with changes in output speed intermittent adhesion and interrupts. Most of the plastic is naturally slid in the roots, because they enter the cold, and the frictional force is not the root and the cylindrical wall is heated to the same heat. Some materials are more likely than other materials adhesion: highly plasticized PVC, amorphous PET, and the use of some of the desired final adhesion properties of the polyolefin has a total polymer. For the cylinder, it is necessary to adhere to the plastic so here it is scraped off by the screw thread to move forward. Should have a high coefficient of friction between the particles and the cylinder, and the friction coefficient, in turn, is strongly influenced by the temperature of the barrel. If the particles are not adhered to, they just rotate in place without moving forward - which is why a smooth material into the bad reasons. Surface friction is not the only factor affecting feed. Many particles never touch the barrel or screw root, so the particles must have an internal matter and mechanical friction and viscosity of the chain. With grooved body is a special case. Grooves in the feed zone, the feed zone and the rest of the thermal insulation cylinder, and the depth of the water-cooled. Thread the particles are pushed into the slot and within a relatively short distance to form a very high pressure. This allows the same amount of increase in the output of the occlusal screw speed is low, the friction heat generated thereby reducing the front end of lower melt temperature. This may mean that the cooling limit of the blown film production line faster production. Particularly suitable groove HDPE, which is in addition to the slippery plastic perfluorinated ordinary plastic. 6 the maximum material cost in some cases, the material costs can account for 80% of the production costs - all other factors, and more - in addition too few quality and packaging products, such as particularly important for medical catheters. This principle naturally leads to two conclusions: processors should be reused as much as possible instead of scrap and waste materials, and comply with the departure from the target thickness tolerances to avoid problems and product strictly as possible. 7 Energy costs are relatively unimportant despite the attractiveness and the real issues and rising energy costs of a plant on the same horizontal line, run an extruder energy required is still a small part of total production costs. This is always the case because the material cost is very high, the extruder is an effective system, if introduced too much energy so the plastic will quickly become very hot so can not be properly processed.