The basic types of injection screw and main parameters:
Injection screw is generally divided into three sections compression section homogenization section.
feed sectionbottom diameter is smaller, the main role is to transport raw materials to the rear section. So the main problem is the transmission capacity. Parameters (L1, h1), h1= (0.12-0.14) D.
compression section variable bottom diameter, the main role is to compact and melt plastic materials, create pressure. Parameters the compression ratio ε=h1／h3 and L2. Gradation degree A = (h1 h3)/ L2.
homogenization section(metering section) push the materials melted in the compression section to the front of the injection screw quantitative in a constant temperature. Parameters (L3, h3), h3 = (0.05-0.07) D.For whole screw, the parameter L/D length-diameter ratio.
L/D pros and cons: L/D and revolution speed n, are the important factors of injection screw capacity and effect. If L/D is large, the materials will has a long residence time in the barrel. It is propitious for plasticizing, and lessen pressure flow and leakage current in the meantime. Its improves the plasticizing capacity, while avail the materials which has high requirements on the temperature distribution. But its also has negative impact on the manufacture, assembly and use. L/D generally equal with 18-20, but the trend has increased.
Pitch S, lead angle φ =πDtgφ, generally, if D = S, then φ =1740'.
φ impacts on the plasticizing capacity, in general, the larger φ the faster transmission speed. So different materials shapes with different φ values. Powder desire φ around 25, cylindrical materials desire φ around 17, square materials desire φ around 15. But the different φ values, in terms of processing, will also be more difficult, so it is usually taken φ1740′.
Rib width e, in terms of low viscosity materials, e try to get bigger, too small to leakage, but too big will increase power consumption and easy to overheat. e =（0.08～0.12）D.
Materials features are listed below, you can choose an appropriate injection screw base different materials.
PC materials(polycarbonate)
Features: ① non-crystalline plastic, no obvious melting point, glass transition temperature of 140 ~ 150 ℃, melting temperature of 215 ℃ ~ 225 ℃, mold temperature 250 ℃ ~ 320 ℃.
read more click here.
(edit by SINO MOULD [email protected])
Injection screw is generally divided into three sections compression section homogenization section.
feed sectionbottom diameter is smaller, the main role is to transport raw materials to the rear section. So the main problem is the transmission capacity. Parameters (L1, h1), h1= (0.12-0.14) D.
compression section variable bottom diameter, the main role is to compact and melt plastic materials, create pressure. Parameters the compression ratio ε=h1／h3 and L2. Gradation degree A = (h1 h3)/ L2.
homogenization section(metering section) push the materials melted in the compression section to the front of the injection screw quantitative in a constant temperature. Parameters (L3, h3), h3 = (0.05-0.07) D.For whole screw, the parameter L/D length-diameter ratio.
L/D pros and cons: L/D and revolution speed n, are the important factors of injection screw capacity and effect. If L/D is large, the materials will has a long residence time in the barrel. It is propitious for plasticizing, and lessen pressure flow and leakage current in the meantime. Its improves the plasticizing capacity, while avail the materials which has high requirements on the temperature distribution. But its also has negative impact on the manufacture, assembly and use. L/D generally equal with 18-20, but the trend has increased.
Pitch S, lead angle φ =πDtgφ, generally, if D = S, then φ =1740'.
φ impacts on the plasticizing capacity, in general, the larger φ the faster transmission speed. So different materials shapes with different φ values. Powder desire φ around 25, cylindrical materials desire φ around 17, square materials desire φ around 15. But the different φ values, in terms of processing, will also be more difficult, so it is usually taken φ1740′.
Rib width e, in terms of low viscosity materials, e try to get bigger, too small to leakage, but too big will increase power consumption and easy to overheat. e =（0.08～0.12）D.
Materials features are listed below, you can choose an appropriate injection screw base different materials.
PC materials(polycarbonate)
Features: ① non-crystalline plastic, no obvious melting point, glass transition temperature of 140 ~ 150 ℃, melting temperature of 215 ℃ ~ 225 ℃, mold temperature 250 ℃ ~ 320 ℃.
read more click here.
(edit by SINO MOULD [email protected])
