Product defects | Possible reasons | Handling methods |
Extrusion mould distortion | Too short cooling time, not enough cooling for finished products | delay the cooling time |
Too rapid speed for extrusion, forced pull to lead the distortion | Slow down the speed of extrusion die |
Finished product structure with defects | Modify the dies |
Too high temperature for die, poor cooling for finished products | reduce the mould temperature |
Knit line | Insufficient injection pressure, too slow injection speed, too small gate and flowing pipe | Increase the injection pressure and injection speed, modify the gate and flowing pipe. |
Too low forming temperature and mould temperature | Increase temperature, increase back pressure or accelerate the rotating speed of screw |
Insufficient exhaust in interflow zone and no run-off pit | Fix exhausting holes in interflow zone and increase the number of run-off pits. |
Use too much release agent | Reduce to use release agent |
Poor luster of finished products | Too slow injection speed, insufficient pressure and low mould temperature | Increase the injection speed, injection pressure and mould temperature |
Hydrosphere or grease pollution in the mould cavity | Clean it up |
Poor grinding of mould surface or too small gate and flowing pipe | Modify mould |
Insufficient injection quantity or water contained in the raw material | Increase the injection pressure and injection speed, delay the jetti |
Cracks of extrusion mould of finished products | Too low temperature of material or mould | Increase the temperature |
Insufficient stripping lean or improper extrusion way | Modify the mould |
Too small gate | Modify the mould |
Insufficient stripping angle | Modify the mould |
Coarse surface of extruded finished products | Too low forming temperature | Increase the temperature, accelerate the rotating speed of screw |
Too low mould temperature | Increase the mould temperature |
Surface blocks of extruded finished products | Not clean material pipes, contain wastes | Clean up material pipe |
The additive articles such as color master batch are not done according to the requirements | look for the corresponding color master batch |
Insufficient extrusion quantity | Insufficient temperature for material pipe | Increase the temperature |
Wastes in the gate or too low speed rate of screw | Clean up the gate or accelerate the rotating spped of screw |
Extrusion mould expansion of extruded products | Too low temperature of mould head or too fast rotating speed of screw | Increase the mould head temperature and reduce the rotating speed of screw |
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Too fast limited material | Adjust the limited material device |
Produce much gas when extruding | Too high melting temperature | Reduce the melting temperature |
Wastes in the material pipe | Clean up the material pipe |
Pits of extruded products | Water contained in the raw material | Dry the material |
Too high meting temperature, too fast rotating speed of screw | Reduce the meting temperature, and the rotating speed of screw |
