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

Compression moulding / sintering
Compression moulding and sintering are used to produce
stress-relieved semi-finished products and custom castings
with a minimal tendency to warp. The so-called compression
moulding technique is used to manufacture semi-finished
products. The process uses powdered particles which
are pressed at high temperature under pressure into a
mould. Because of the amount of time involved and the
materials used, this process is relatively labour intensive
and costly. Unlike the compression moulding method, the
matrix compression or direct forming technique allows the
direct production of off-tool custom castings. As a special
mould is required, this process is generally only profitable
for a production run of around 1,000 pieces.
Cast polyamide
Pressureless custom casting has proved to be a particularly
successful method for the production of bulky thick-walled
components which are almost fully finish processed.
Alongside custom casting, cast polyamide semi-finished
products can also be produced using the semi-finished
product casting technique in the form of plates and rods
with substantially larger dimensions than when using the
extrusion method.
Semi-finished products and custom castings produced using
this method have a lower intrinsic stress level than extruded
products. Casting methods are ideally suited for
small and medium-sized production volumes in a weight
range of 0.5 to 900 kg.
Machining
Machining is the fastest, most economical way to arrive at a
finished plastic component, in particular for small production
runs. Using the machining technique, finished components
with extremely close tolerances can be produced
from engineering and high-temperature plastics. This entails
the use of CNC milling machines, lathes or saws fitted
with special tools for machining plastics to shape the finished
parts from plastic stock shapes or pre-produced injection-moulded
components.
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