PREMIX MOULDING (BMC MOULDING): (GUNK MOULDING) in FRP

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.