pvc pipe extrusion die/pvc pipe die/pvc pipe mould/plastic pipe mould/pvc pipe extrusion die design/pvc pipe making mold

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

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