The extrusion moulding is a common method for making of Pipe, Rods, Hoses, Driking Staws and more. The Die is Main Part of extrusion moulding process, because of the product cross section depends on the Die Cross section. The Screw part is inside a barrel. First the extrusion of plastic is form of powder, it fed into screw from hopper. It conveyed through barrel and heated by Heater Conduction process. In this extrusion process the shear force made by screw movement. Finally, the end of extruder the extrusion of plastics passed through die to make the require shape object.
Schematic Diagram for extrusion of Plastics
Die Configuration for extrusion of plastics process.
That should be having mainly three zone:
(i) Feed Zone for extrusion moulding process:
In this process the plastic is pre heated and convey to subsequent zone.The Raw material is pass to feed zone from hopper. The heater is heated by the materiel. The screw will be designed in constant depth and supply some sufficient amount of material to the metering zone.
(ii) Compression Zone For extrusion of plastics:
In this Zone, The cross Section of screw depth will be gradually decrease, so compact the plastic. The Compaction process any trapped air back into feed zone and thickness of material reduced by heat transfer from heater.
(iii) Metering zone for extrusion process
The metering zone, again the screw depth will be decrease and it much lower than the feed zone. The melton metal pass to the die with constant rate, uniform pressure and temperature .
Some of extrusion moulding advantages and disadvantages:
The Main advantage of extrusion moulding is
- to make long shape of object
- the machining cost will be low
- Efficient of melting Process
- Mass production volume
- Good mixing of Metal (compounding)
Some Disadvantages of process
- Limited complexity of parts
- Uniform cross-sectional shape only manufactured