Pipe Extrusion

PIPE EXTRUSION:

1. Pipe extrusion is defined as a process of forcing the polymer melt through a shaping die (in this case: circular). 

2. The extrudates from the die is sized, cooled and the formed pipe is pulled to the winder or a cut off device with the aid of haul off device. 

Prior to this, the plastic material in the form of polymer granules is fed into the hopper, conveyed by a rotating screw through a long cylindrical barrel. 

3. This is subjected simultaneously to high temperature and pressure, forcing the melt through the die at a predetermined rate.

Materials: 

After Polyvinyl chloride (PVC), Polyethylene's (PE) is the most widely used thermoplastic piping material.

Applications

1. Irrigation Drip, Sprinkler and Lift Irrigation 

2. Water transportation Potable water, drainage, sewage 

3. Industrial Chemicals, sandstowing, dewatering in mines, dredge pipelines, gas distribution and low voltage telecom/power cables 

PE piping systems has many distinct advantages over conventional piping materials. 

1. Lightweight 

2. Flexible 

3. Long lasting 

4. Economical 

5. Easy for transportation & installation. 

CO-EXTRUSION

Co-extrusion is a process of extruding two or more materials through a common die.

The dies have two or more orifices arranged so that the extrudates merge and weld together into a laminar structure before chilling. 

Each material is fed to the die from a separate extruder, but the orifices may be arranged so that each extruder supplies two or more plies of the same material. 

Advantages

1. Provides better quality monolayer extrusion coatings over a wider variety of widths and line speeds

2. Save the amount of premium resins by filling with lower cost materials

3. Make multi-layer, multi-functional structures in a single pass.”

Disadvantages

1. Polymers for coextrusion should have similar melt viscosities to maintain laminar flow. 

2. Viscosity differences can be more or less tolerable depending on the location of the material in the composite structure and the thinness of the layer.

3. It requires a more sophisticated extruder operator.

4. Provides the potential to create expensive scrap quickly.

5. Complexity of the equipment added maintenance cost.