An experimental investigation into resonance dry grinding of hardened steel and nickel alloys with element of MQL

Current policies on environmental issues put extra pressures on manufacturing processes to be resource efficient and eco-friendly. However, in grinding processes, large amounts of cutting fluids are used. These fluids are not environmental friendly thus require proper management before disposal with associated cost. Hence, this work sets to explore low-frequency vibration in grinding in order to improve coolant application in conventional grinding at the first stage with the aim to introduce this into high efficiency deep grinding (HEDG) at latter stage. An attempt is made to grind nickel alloys with minimum quantity lubricant (MQL) as oppose to flood cooling. To achieve this with minimum alterations to the machine tool, a piezo-driven workpiece holder was developed for surface grinding. This simple innovative workpiece holder allowed oscillating during actual grinding process. However, this paper presents the results of low-frequency oscillatory grinding in dry and near-dry conditions. The response of the machine tool spindle unit is presented alongside with the workpiece holder response. In this investigation, hardened steels and nickel alloys were ground with vibration assistance. The grinding forces are illustrated together with the surface finish. The wheel performance is given in terms of grinding ratio

A cutting force model based on kinematics analysis for C/SiC in rotary ultrasonic face machining

Ceramic matrix composites (CMC) superior properties and are used in the harsh conditions of high temperature and pressure, in aerospace and other industries. However, due to inhomogeneous and anisotropic properties of the composites, the machining is still challenging to achieve desired efficiency and quality. For advanced materials, Rotary ultrasonic machining is considered as a process with high efficiency technology. The cutting force is a critical factor required to be effectively predicted and controlled to reduce processing defects in composites. In this research, the rotary ultrasonic machining was used for face machining of carbon reinforced silicon carbide matrix composites (C/SiC), with a conical shaped tool. The kinematics between individual diamond abrasive and the workpiece material was analyzed to illustrate the separation characteristics in the cutting area. The condition for the intermittent machining during RUFM was obtained by establishing the mathematical relation between cutting parameters and vibration parameters. The indentation fracture theory was adopted to calculate the penetration depth into the workpiece by diamond abrasives in the RUFM. The relationship of cutting force and processing parameters including spindle speed, feed rate, and cutting depth were investigated. The comparison of the experimental and simulation data of the cutting force, showed that most of the tests, the errors were below 15 %. It is therefore stipulated that the cutting force model developed in this paper can be applied to predict cutting forces and optimize the process in the RUFM of C/SiC

Improving Commercial Motor Bike Rim Disc Hardness Using a Continuous-Wave Infrared Fibre Laser

This study is focused on examining the feasibility of applying laser hardening to a commercial metallic bike rim, employing a CW IR fibre laser. The research comprises two main phases. The first phase involves an assessment of the impact of laser parameters on the metallic microstructure, while the second phase involves the actual laser hardening of the bike rim. A comprehensive evaluation encompassing hardness measurements, optical microscopy, and scanning electron microscopy was conducted on the samples. The microstructure type can be manipulated by skilfully adjusting the laser parameters, allowing for the creation of various microstructure variants within the laser-hardened zone for specific laser conditions. In this regard, multiple microstructure types were observed. The hardness of the laser-processed zones exhibited variations corresponding to the specific microstructure. Notably, the molten zone (MZ) and the second heat-affected zone (HAZ II) exhibited the highest levels of hardness. Furthermore, it was observed that a scan overlap of ≥ 75% led to an augmentation in hardness. This study sheds light on the intricate interplay between laser parameters, microstructure, and resultant hardness in the context of laser hardening of metallic materials