Housing parts

Thermosetting plastics in the electronics industry

Poly-stuffer

BMC stuffering device for thermoset processing

Poly-stuffer

BMC stuffering device for thermoset processing

Poly-stuffer

BMC stuffering device for thermoset processing

Poly-stuffer

BMC stuffering device for thermoset processing

Non-flowing thermosets/BMC

BMC is a glass-fibre-reinforced polyester bulk moulding compound, which is usually supplied in bales. It is a non-free-flowing thermosetting moulding compound, which is formed by the thickening of liquid unsaturated polyester resins using earth oxides.

Benefits

  • Very good dimensional stability
  • High continuous operating temperature
  • Good chemical resistance
  • Very good mechanical properties
  • Efficient cost-performance ration
  • Good electrical properties
  • Tried-and-tested process

The non-free-flowing material necessitates an adapted material feed into the plasticating unit by means of a special pushing device or ‘stuffer’. With the beginning of the plasticating process, the screw of the stuffer rotates and conveys the BMC into the plasticating cylinder under a defined stuffer pressure. The stuffer control unit is integrated in the machine control system and enables control of the stuffing pressure for a constant material feed. The plasticating unit comprises a screw adapted to the BMC processing and a cylinder which is temperature-controlled using liquid chemical agents. The machine has an integrated electric mould heating unit for heating the mould to a temperature ranging from 140°C to 200°C and to accelerate the cross-linking reaction. As soon as the dimensionally stable state is reached, the formed parts can be demoulded.

The stuffer for charging the material (on the right) as well as the large extraction systems above the stuffer and the mould area are the most obvious differentiating features compared to a thermoplastic injection moulding machine.