Synthetic granite composite for precision equipment structures

João Fiore Parreira Lovo,Benedito De Moraes Purquerio,Rogério Erbereli,Carlos Alberto Fortulan,Marcos Paulo Gonçalves Pedroso

doi:10.1590/s1517-707620180004.0563

Abstract

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

Highlights

Structural materials play a key role in equipment’s operation and performance
Composition A showed tensile and compression strengths gain of about 80% and 30% respectively compared to traditional synthetic granites formulations of literature [9]
Synthetic granite composite presents itself as a valuable alternative for precision machine structures manufacturing and has been explored since the 1970s

Summary

Introduction

Structural materials play a key role in equipment’s operation and performance. the material selection must ensure the performance of the device function in order to withstand stresses by providing adequate integrity and stability in service [1-3], meet specific needs such as strength, hardness, durability, rigidity, weight, heat and corrosion resistance, electrical conductivity, machinability, besides environmental characteristics and compatible cost with equipment value, the main structural materials generally used are cast iron, aluminum, composites in general and engineering polymers [1,4-6].In modern engineering concept the equipment must have compatible dimensions with the products and environments with which they work [4,7], optimizing space and weight in the allocated environment. The material selection must ensure the performance of the device function in order to withstand stresses by providing adequate integrity and stability in service [1-3], meet specific needs such as strength, hardness, durability, rigidity, weight, heat and corrosion resistance, electrical conductivity, machinability, besides environmental characteristics and compatible cost with equipment value, the main structural materials generally used are cast iron, aluminum, composites in general and engineering polymers [1,4-6]. In a precision device the structure material must enable the fabrication of elements with reduced dimensions, low deformation by thermal variations, and vibrations dampening [8-11]. Manufacturing is another aspect that deserves to be highlighted, especially in small scale concept devices, since the investment in molds, casting and machining can become infeasible designs [7,12,13]. Synthetic granite composites are still advantageous because it allows the inserts application in the functional parts of the equipment, fluid and spinning ducts, voids of mass relief, lifting inserts and still allows the use of industrial waste, conferring an advantageous environmental and economic character to the material [15,17,18]

Objectives

Methods

Results

Conclusion