Engineering plastics – The Manual - F.wood-supply.dk

Processing methods
Compounds, semi-finished and finished products are manufactured
with the aid of the following process techniques:
Compounding
During compounding, plastic raw materials are melted
with fillers or additives, extruded into thin strands and then
cut into granulate. This process allows the characteristics of
the plastics to be adapted for special applications, for instance
by improving the sliding friction properties or increasing
electrical conductivity.
Extrusion
Pressure and temperature-regulated extrusion is a continuous
production process in which plastics are plastified in
an extruder and then forced at pressure through a specially
shaped die. The cross-section of the resulting geometric
shape equates with the used die or calibration.
The extrusion process is an efficient method of manufacturing
semi-finished products, also known as stock shapes,
with large wall thicknesses and dimensions. The portfolio
of semi-finished products comprises rods, tubes and plates
in a wide variety of dimensions and colours.
Injection moulding
Injection moulding is a highly productive forming process
for the mass manufacture of finished components capable
of immediate commercial use. The plastic is melted using
an extruder, plasticized and then injected at pressure into
the injection moulding tool. The cavity of the tool determines
the shape and surface structure of the finished component.
The injection moulding process is usually only
economical for large production runs due to the tooling
costs involved.
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