An Original Tribometer to Analyze the Behavior of Abrasive Grains in the Grinding Process

Abstract

Abstract:Manufacturing of grinding wheels is continuously adapting to new industrial requirements. New abrasives and new wheel configurations, together with wheel wear control allow for grinding process optimization. However, the wear behavior of the new abrasive materials is not usually studied from a scientific point of view due to the difficulty to control and monitor all the variables affecting the tribochemical wear mechanisms. In this work, an original design of pin-on-disk tribometer is developed in a CNC (Computer Numerical Control) grinding machine. An Alumina grinding wheel with special characteristics is employed and two types of abrasive are compared: White Fused Alumina (WFA) and Sol-Gel Alumina (SG). The implemented tribometer reaches sliding speeds of between 20 and 30 m/s and real contact pressures up to 190 MPa. The results show that the wear behavior of the abrasive grains is strongly influenced by their crystallographic structure and the tribometer appears to be a very good tool for characterizing the wear mechanisms of grinding wheels, depending on the abrasive grains.

Modelling the wear evolution of a single alumina abrasive grain: Analyzing the influence of crystalline structure

“…As it is previously mentioned, this numerical work is based on previous experimental analysis of alumina wear under real grinding conditions Godino et al (2018aGodino et al ( , 2018b. Firstly the wear was analyzed during grinding and secondly using a pin on disk tribometer.…”

“…4. A spherical abrasive grain of 300 μm in diameter is modeled in order to validate the numerical wear model with pin on disk test results, as previously carried out by Godino et al (2018b). A semi-sphere is modeled since more than 50% of the abrasive grain is embedded in a wheel matrix.…”

“…Moreover, this author confirmed that the microcrystalline alumina present lower thermal conductivity than conventional alumina. With the aim of addressing the two limitations of Mayer´s work, along with the randomness of the grinding process, Godino et al (2018b) examined the wear of alumina abrasive grains from a tribological point of view. The new design of pin on disk tests allows for monitoring contact conditions and reproducing the real contact of abrasive grains, along with their thermal cycle.…”