Synthetic granite composite for precision equipment structures

Résumé

The structure is a component that plays an extremely important role in the equipment’s performance, it must
withstand efforts without compromising the function, receive and transfer heat, dampen vibrations and
position the elements, as well as promote ergonomics and aesthetics. In lightweight and precision
equipment’s the raw material used must also allow thin walls, rigid, resistant and low density. The objective
of the present work is the development of a synthetic granite composite for manufacturing of equipment’s
structures. For this, an abundant Brazilian granite, a high strength epoxy resin and segmented carbon fibers
were selected as materials. Test specimens, with maximized packing with granite gravel less than 2.0 mm
were fabricated and tested for tensile strength, compression, flexural, damping, hardness, dilatometry,
thermal conductivity and density. The maximized composition supported flexural stresses above 42 MPa,
without fiber reinforcement and 51 MPa with carbon fiber reinforcement. The damping coefficient was about
7 times higher than cast iron, coefficient of thermal expansion of 1.4E-05 m/m.K, thermal conductivity
coefficient of 1.2 W/m.K and density of 2.1 g/cm³. The developed composite showed potential for refining
structures, with ease of molding of thin-walled elements, use of inserts, re-machining, providing economical
manufacture of single parts, and is still able to perform the function with high damping coefficient and low
weight.
Keywords: Synthetic granite, composite, machine structure, damping