Design of an experimental grinding machine for testing abrasive wheels with a 3D internal cooling channels structure

Abstract

Precision manufacturing often utilizes grinding as a method to fabricate components with accuracy, enhanced surface quality, and desirable forming tolerances. The working conditions of a grinding machine and the attributes of the abrasive wheel play a crucial role in influencing the grinding process. Main challenges in grinding are related to heat dissipation, resulting in issues such as tool wear, increased forces, and thermal damage. To effectively dissipate heat from the machining zone, grinding fluids are employed in the majority of grinding processes. Namely, the quantity of grinding fluid and its distribution, directly impacting its effectiveness in reaching the contact zone between the abrasive wheel and the workpiece surface. Surface textured abrasive wheels present a promising solution by augmenting heat dissipation, thereby reducing temperatures and fluid consumption during grinding. This work introduces a specialized grinding apparatus designed for both Down-grinding and Up-grinding processes. Crafted for abrasive wheels with 3D internal cooling structure channels, the equipment is specifically engineered to address challenges associated with heat generated during these operations. The equipment was designed to supply coolant through the central orifice of the structured abrasive wheel. This configuration facilitates fluid flow through the channels towards the periphery of the wheel. The implementation of this internal delivery system not only reduces the volume of coolant required but also directs it precisely to the contact zone between the abrasive wheel and the workpiece. This not only optimizes the cooling effect but also enhances the efficient removal of wear debris. The equipment was designed to accommodate abrasive wheels with diameters ranging from 45 to 110 mm and workpieces with a maximum area of 100 x 110 mm. It can achieve rotational speeds between 500 and 14,000 rpm, a feed rate of up to 150 mm/min, and a minimum penetration depth of 10 µm. Furthermore, this equipment features an integrated coolant supply system with a flow rate of up to 4 L/min, allowing a flexibility of both internal and external fluid supply options, also offering the possibility of conventional abrasive wheels to be used. In addition to a diverse range of grinding operations, the monitoring capabilities extend to measuring forces exerted in all three axes (xx, yy, and zz) throughout these processes. Experimental tests were conducted, involving both conventional and structured abrasive wheels. These tests facilitated the assessment of distinctions between the two lubrication methods through the analysis of tangential (xx) and normal (zz) forces.