In this
process finished part is obtained while in BMC / DMC is the raw stock
manufacturing process.
1.
It
is a form of compression or transfer moulding.
2.
It
uses dough or putty like moulding like compound called premix.
3.
Preparation
of premix: The premix can be made by careful mixing of the ingredients in the
mixer and in large production, this mixture is directly fed to an extruder
which then prepares long lengths of material which is cut to sizes and fed to
the press as premix.
4.
Compounding:
It can be done at high pressure of several tons or at low pressure of several
hundred pounds.
5.
Trouble
shooting in processing premix compound:
Problem:
Possibility of non-homogenous compound being prepared and/or a non-isotropic
part being prepared.
Solution:
Careful attention to mixing procedure and part design details (tending to
accurate resin segregation or trap filler during compound flow in the
mould)
6.
Advantages:
Rapid cycles at lower pressures with low cost materials.
7.
Applications:
a.
Mouldings
are most competitive in areas where the die and sand castings were formerly
used.
They find wide acceptance in
electrical and electronics field, business machine housings, home appliances
etc. because of good physical and electrical properties; ability to mould
delicate inserts to precise tolerances.
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