Analytical modeling of surface generation in ultrasonic ball burnishing including effects of indentation pile-up/sink-in and chipping fracture

Abstract

In mechanical based machining processes, the surface topography is generated through series of hierarchical pattern. Plastic deformation as result of contact and kinematic of motion are two main factors which determine evolution of surface generation. To basically optimize the surface quality, accurate predictive model of surface generation and constraints are required. In the present work, analytical models of dimple formation and hierarchical surface generation in ultrasonic assisted ball burnishing process are proposed. Pileup and sink-in as two phenomena of indentation during both of loading and unloading phases were taken into the developed models. Considering interaction of indentation profile and kinematic of motion, three-dimensional surface topography and surface roughness are also analytically predicted. A criterion for surface failure is defined to perform process without any erosion. Confirmation of results have been made by series of single trace and multitraces burnishing experiments on AA6061-T6 and AISI 1045. The results of indention profile, surface topography, roughness and failure criterion which were derived from predictive models were completely consistent with confirmatory experiments.

Corrosion resistance of 3D printed SS316L post-processed by ultrasonic shot peening at optimum energy level

“…On the other hand, as result of contact of larger ball with the surface, the pile-up height that is generated around the indent is bigger that results formation of rough surface. 28 According to the influence of ball size on surface roughness, it can be understood that the reason for increasing the corrosion rate by ball size (from 2 to 4 mm) is because of further surface roughness. The reasons for the reduction at 6 mm ball size can be due to variation of other quality characteristics that is discussed as follows: Figure 5(b) illustrates influence of ball size on surface hardness compressive residual stress.…”

Shot peening of selective laser-melted SS316L with ultrasonic frequency

“…5 3D surface plots showing interaction effects of process factors on hardness (a) ultrasonic power and process time (b) ultrasonic power and shot diameter (c) ultrasonic power and gap distance (d) gap distance and shot diameter of the main reasons for this roughness value is as result of pile-up formation during impact. According to Teimouri et al [24], the pile-up which is formed during impact treatment depends to the material, and kinetic energy. As the stainless steel is a material prone to form pile-up during impact, by increasing the ball diameter, the pile-up height increases that results in greater surface roughness.…”