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Changshu smoothly da plastic products factory talk about four plastic flow state in the process of extrusion
by：CSSSLD
2021-01-23
In extrusion process, due to the rotation of the screw plastic, and barrel is motionless, the relative movement between barrel and screw, the relative movement of plastic friction effect, make plastic dragged forward.
In addition, because the nose of the mould, porous sieve plate and the resistance of the filter, and make the plastic reaction in advance, which makes the plastic flow in the screw and barrel complicates.
Changshu well below da plastic products factory talk about plastic extrusion process under four kinds of flow state!
are flow - refers to the plastic along the screw screw groove to the head in the direction of flow. It is the pushing force screw rotation, is one of the main forms of four kinds of flow. The size of the positive flow directly decides the extrusion.
back - also called upstream, its direction and the direction of flow is the flow of the whole good instead. It is due to the nose of the mold, sieve plate, positive movement and mesh obstacles such as plastic, the pressure generated in the nose area ( Plastic forward reaction) . From the nose to feeding mouth formed & other; Pressure backflow & throughout; , also known as & other; Back pressure flow & throughout; 。 It can cause the loss of production capacity.
cross flow, it is along the axial direction, namely with thread groove plastic flow in vertical direction. Is formed by the screw rotates the push. The flow resistance by thread slot wall, due to the mutual resistance on both sides of the screw, the screw is in the rotation, make plastic to produce reverse movement in the spiral groove, a circular flow, so the cross flow essence is circulation. Mixing barrel of the circulation of the plastic, plastic into molten state, and the role of circulation inseparable. Circulation materials in the barrel of stirring and mixing, and benefit for the heat exchange of the barrel and material, it has important significance to improve the quality of extrusion, but little impact on extrusion flow rate.
leakage flow, it is also a mould, sieve plate from the nose and the resistance of the screen. But it isn't flow in screw slot, it is formed in the clearance between the barrel and screw back. It also can cause the loss of production capacity. Due to the clearance between the barrel and screw usually is very small, so in normal circumstances, leakage flow is much smaller than is flow and put back the clock. In the extrusion process, the leakage flow will affect the amount and leakage flow rate increases, extrusion amount will be reduced.
the four plastic flow state will not take the form of individual, as for a plastic particles, both neither can have a real go back, also won't have a closed circulation. Melt the plastic in the threads of the actual flow is a combination of the above four kinds of flow state, with spiral path forward a kind of flow.
are flow - refers to the plastic along the screw screw groove to the head in the direction of flow. It is the pushing force screw rotation, is one of the main forms of four kinds of flow. The size of the positive flow directly decides the extrusion.
back - also called upstream, its direction and the direction of flow is the flow of the whole good instead. It is due to the nose of the mold, sieve plate, positive movement and mesh obstacles such as plastic, the pressure generated in the nose area ( Plastic forward reaction) . From the nose to feeding mouth formed & other; Pressure backflow & throughout; , also known as & other; Back pressure flow & throughout; 。 It can cause the loss of production capacity.
cross flow, it is along the axial direction, namely with thread groove plastic flow in vertical direction. Is formed by the screw rotates the push. The flow resistance by thread slot wall, due to the mutual resistance on both sides of the screw, the screw is in the rotation, make plastic to produce reverse movement in the spiral groove, a circular flow, so the cross flow essence is circulation. Mixing barrel of the circulation of the plastic, plastic into molten state, and the role of circulation inseparable. Circulation materials in the barrel of stirring and mixing, and benefit for the heat exchange of the barrel and material, it has important significance to improve the quality of extrusion, but little impact on extrusion flow rate.
leakage flow, it is also a mould, sieve plate from the nose and the resistance of the screen. But it isn't flow in screw slot, it is formed in the clearance between the barrel and screw back. It also can cause the loss of production capacity. Due to the clearance between the barrel and screw usually is very small, so in normal circumstances, leakage flow is much smaller than is flow and put back the clock. In the extrusion process, the leakage flow will affect the amount and leakage flow rate increases, extrusion amount will be reduced.
the four plastic flow state will not take the form of individual, as for a plastic particles, both neither can have a real go back, also won't have a closed circulation. Melt the plastic in the threads of the actual flow is a combination of the above four kinds of flow state, with spiral path forward a kind of flow.
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