BMC
BMC (Sheet Molding Compound) is used in hot press compression molding for the production of large parts with high mechanical properties and excellent surface quality.
BMC is a polymeric composite material mainly composed of thermoset resin, mineral fillers and glass fiber reinforcement. The resin used is usually unsaturated polyester. Additional components such as thermoplastic components, catalysts, inhibitors, mold release agents, thickeners and color pigments are used to improve the performance of the final product and the molding process.
The molding process is in a hot mold at temperatures between 140 – 155ºC and under pressure. It is carried out in hydraulic presses specially designed for this process.
BMC Production Process
Resins, fillers and additives are automatically weighed and mixed together to form the master paste. In a second mixer, more filler, color pigment and chopped fiberglass are automatically weighted and mixed together in a computer-controlled process to ensure perfect impregnation or wetting of the glass fiber.
The resulting mixture is then sent to an extruder, which compresses the BMC material and packs it into bags. At the end of the process, the BMC bags are packed in boxes after the BMC bags have passed through a metal detector to prevent the material from having any metallic foreign objects.
BMC can be molded in both injection and compression processes for large-scale production of medium to small complex parts. Although molding activities are performed by our customers, Aykom assists during molding trials and offers complete technical assistance whenever needed.
| TYPICAL PROPERTIES | Standard | Units | |
| Density | ISO 1183 | g/cm³ | 1,85 |
| Shrinkage | ISO 2577 | % | 0,05 |
| Heat Distortion Temp | EN ISO 75-2 | °C | >200 |
| Continuous Service Temp | Aykom | °C | 155 |
| Young’s Modulus | EN ISO 527-4 | GPa | 13 |
| Tensile Strength | EN ISO 527-4 | MPa | 35 |
| Flexural Strength | EN ISO 14125 | MPa | 110 |
| Flex Modulus | EN ISO 14125 | GPa | 10 |
| Impact Strength | EN ISO 179 | kJ/m² | 30 |
| Clow Wire Index | IEC 60707-3 | °C | 750 |
| Fire Retardancy | UL 94 | HB@3 mm | |
| Surface Resistivity | IEC 60093 | Ohm | 10¹² |
| Comparative Tracking Index | IEC 60112 | Level | CTI600 |
| Water Absorption | ISO 62 | % | < 0,5 |
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