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Changshu smoothly of plastic extrusion factory talk about 10 principle of plastics extrusion
by：CSSSLD
2021-01-23
Working principle of screw extruder is depend on the screw rotation generated by pressure and shearing urged make plastic raw materials sufficient plasticizing and mixing, eventually forming through the mouth.
The following works of plastic extrusion factory in changshu, say ten principles of plastic extruding.
Mechanical principle
1
most single screw is right hand thread, such as carpentry and machine used in the screw and bolts. If they are seen from behind the reverse rotation because they try to turn the cylinder back. Two in twin screw extruder screw reverse rotation in two cylinder and cross each other, so one must be right to another must be left to.
2 hot principle
thermoplastic plastics commonly used in extrusion production, plastic raw materials when melt when heated and cooled curing again. Motor input energy and overcome the resistance of the viscous melt the generated when the screw on cylinder body is all plastic friction heat in the most important source of heat when it is squeezed.
3 reduction principle
in the majority of extruder screw speed change by adjusting the motor speed. Motor usually at about 1750 r rotation at full speed but it was too fast for a screw extruder. If at such a fast speed rotating friction will generate too much heat and plastic retention time is too short and the preparation of uniform, good mixing of the melt. Typical reduction ratio between 10:1 and systematically.
4 feed as a coolant
extrusion process is to transfer the energy to heating not allowing the molten plastic, input feed than feeding area of the cylinder and the screw surface temperature is low. While feeding area of the cylinder surface temperature on the plastic melting point through contact with the feed particles and cooling, controlled by the heat front-end backward heat transfer and heat to keep the heat. Even by the viscous friction heat to keep the current end without the need for cylinder may need to open the heater when the heat input.
5 incoming materials in the area to the cylinder on the slide to the screw on the
in order to make a single screw extruder, smooth solid particles throughput reach the maximum of cylinder feeding area, particles should stick on cylinder and slide to the screw. If the particles sticking in the root of the screw, nothing can pull them down, amount of entrance channel and solid volume should be reduced. Bad adhesion in the root of another reason is the plastic may be hot here and produce gel and similar pollution particles, or intermittent interruption of adhesion and along with the change of output speed.
6 materials has the highest cost
in some cases the cost of materials can be accounted for 80% of the cost of production more than the sum of all other factors. This principle nature leads to two conclusions: processors should reuse wastes and waste as much as possible instead of raw materials, strictly abide by the tolerance as much as possible so as not to deviate from the target thickness and product problems.
and energy costs are relatively is not very important, run a extrusion machine the required energy is, in fact, a few in the total production cost, because the material cost is very high extruder is an effective system, if too much energy is introduced plastic will overheat for normal processing.
7, it is very important to the pressure at the ends of the screw
the downstream pressure reflects the screw all objects: the resistance of the filter and pollution crusher plate, adapter duct, fixed stirrer and mold itself. It is not only dependent on the component geometry, it also depends on the temperature in the system and the resin viscosity and through speed. For security reasons it is important to measure temperature & ndash; — If the temperature is too high die and mold may explode and cause harm to the machine and the nearby personnel.
8. Output
the last thread of displacement is called & lsquo; Is the flow & rsquo; , only rely on the geometry of a screw, screw speed and density of the melt. It logistics by pressure regulating actually includes reducing the resistance effect of the output ( By the highest pressure) And increase the output of any effect of a bite of feed. Thread on the leakage may be an arbitrary direction in two directions.
9 shear rate on viscosity plays a main role in
most plastics have shear thinned feature in the plastic under the higher shear viscosity is lower. And LLDPE shear decline is not too much, double thrust when the velocity is only 3 to 4 times, reduce the shear lower effect means that the extrusion under the condition of high viscosity and increasing the motor power.
10 motor and cylinder of antagonistic
if the cylinder heating wall layer material viscosity decreases, the motor run more smooth in the cylinder body need less energy, reduce power consumption. If a cylinder cooling wall of melt viscosity increases, the motor must be more hard turning, increased amperes, through the cylinder to remove some of the heat was motor back.
1
most single screw is right hand thread, such as carpentry and machine used in the screw and bolts. If they are seen from behind the reverse rotation because they try to turn the cylinder back. Two in twin screw extruder screw reverse rotation in two cylinder and cross each other, so one must be right to another must be left to.
2 hot principle
thermoplastic plastics commonly used in extrusion production, plastic raw materials when melt when heated and cooled curing again. Motor input energy and overcome the resistance of the viscous melt the generated when the screw on cylinder body is all plastic friction heat in the most important source of heat when it is squeezed.
3 reduction principle
in the majority of extruder screw speed change by adjusting the motor speed. Motor usually at about 1750 r rotation at full speed but it was too fast for a screw extruder. If at such a fast speed rotating friction will generate too much heat and plastic retention time is too short and the preparation of uniform, good mixing of the melt. Typical reduction ratio between 10:1 and systematically.
4 feed as a coolant
extrusion process is to transfer the energy to heating not allowing the molten plastic, input feed than feeding area of the cylinder and the screw surface temperature is low. While feeding area of the cylinder surface temperature on the plastic melting point through contact with the feed particles and cooling, controlled by the heat front-end backward heat transfer and heat to keep the heat. Even by the viscous friction heat to keep the current end without the need for cylinder may need to open the heater when the heat input.
5 incoming materials in the area to the cylinder on the slide to the screw on the
in order to make a single screw extruder, smooth solid particles throughput reach the maximum of cylinder feeding area, particles should stick on cylinder and slide to the screw. If the particles sticking in the root of the screw, nothing can pull them down, amount of entrance channel and solid volume should be reduced. Bad adhesion in the root of another reason is the plastic may be hot here and produce gel and similar pollution particles, or intermittent interruption of adhesion and along with the change of output speed.
6 materials has the highest cost
in some cases the cost of materials can be accounted for 80% of the cost of production more than the sum of all other factors. This principle nature leads to two conclusions: processors should reuse wastes and waste as much as possible instead of raw materials, strictly abide by the tolerance as much as possible so as not to deviate from the target thickness and product problems.
and energy costs are relatively is not very important, run a extrusion machine the required energy is, in fact, a few in the total production cost, because the material cost is very high extruder is an effective system, if too much energy is introduced plastic will overheat for normal processing.
7, it is very important to the pressure at the ends of the screw
the downstream pressure reflects the screw all objects: the resistance of the filter and pollution crusher plate, adapter duct, fixed stirrer and mold itself. It is not only dependent on the component geometry, it also depends on the temperature in the system and the resin viscosity and through speed. For security reasons it is important to measure temperature & ndash; — If the temperature is too high die and mold may explode and cause harm to the machine and the nearby personnel.
8. Output
the last thread of displacement is called & lsquo; Is the flow & rsquo; , only rely on the geometry of a screw, screw speed and density of the melt. It logistics by pressure regulating actually includes reducing the resistance effect of the output ( By the highest pressure) And increase the output of any effect of a bite of feed. Thread on the leakage may be an arbitrary direction in two directions.
9 shear rate on viscosity plays a main role in
most plastics have shear thinned feature in the plastic under the higher shear viscosity is lower. And LLDPE shear decline is not too much, double thrust when the velocity is only 3 to 4 times, reduce the shear lower effect means that the extrusion under the condition of high viscosity and increasing the motor power.
10 motor and cylinder of antagonistic
if the cylinder heating wall layer material viscosity decreases, the motor run more smooth in the cylinder body need less energy, reduce power consumption. If a cylinder cooling wall of melt viscosity increases, the motor must be more hard turning, increased amperes, through the cylinder to remove some of the heat was motor back.
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