Ibrahim Deiab

Influence of Tool Materials on Machinability of Titanium- and Nickel-Based Alloys: A Review

Titanium and nickel alloys are the most commonly used in the demanding industries like aerospace, energy, petrochemical, and biomedical. These highly engineered alloys offer unique combination of heat resistance, corrosion resistance, toughness, high operating temperature, and strength-to-weight ratio. These alloys are termed as “Difficult to cut materials” because of their low machinability rating. They are difficult to machine because of properties like low thermal conductivity, high strength at elevated temperatures, and high chemical reactivity. Machining of titanium- and nickel-based alloys causes problems of surface integrity and selection of cutting tool materials that is always a challenge for manufacturers. In this work, machinability studies for titanium and nickel alloys are reviewed with reference to cutting tool materials, associated wear mechanisms, failure modes, and novel tooling techniques. It also discusses major surface integrity defects like carbide cracking, white layer formation, work hardening layer formation, residual stresses, and microstructural alterations. Major aim of this work is to evaluate the challenges involved in improving machinability of the titanium- and nickel-based alloys, and determine the future research direction for productivity improvements in machining these alloys.

Minimal quantity cooling lubrication in turning of Ti6Al4V : Influence on surface roughness, cutting force and tool wear

Titanium alloys generally show low machinability ratings. They are referred as difficult-to-cut materials due to their inherent properties such as low thermal conductivity, high chemical reactivity and high strength at elevated temperatures. Cooling strategies play an important role to improve the machining performance of the cutting process. In order to facilitate the heat dissipation from the cutting zone, generous amount of coolant is used when machining highly reactive metals such as titanium alloys. Generally, cutting coolants are nominated as pollutants due to their non-biodegradable nature. This article presents experimental evaluation of a minimal quantity cooling lubrication system. The study investigates a combination of sub-zero-temperature air and vegetable oil–based mist as possible environmentally benign alternative to conventional cooling methods. The results are compared with the dry and flood cutting environments as well. Machinability was evaluated experimentally by considering the surface finish, cutting forces, tool life and their associated tool wear mechanisms. It was concluded from the results obtained from the surface roughness, cutting force and tool life investigation that minimal quantity cooling lubrication (internal) cooling strategy has encouraging potential to replace the conventional flood cooling method.

On Energy Efficient and Sustainable Machining through Hybrid Processes

The increasing cost of energy, growing global competition, and increasing customer demand for cheaper and more efficient products has placed tremendous pressure on the manufacturing sector to dramatically improve machining efficiency. While improving the efficiency of machining processes increases the competitiveness and profitability of the manufacturing facility, it also results in a cleaner environment and more sustainable processes in terms of better utilization of resources, reduction of waste, efficient use of energy, and lesser CO2 emission. In manufacturing the concept of sustainability is well defined and implemented on the system level, but this is not the case on the micro-level when it comes to machining processes. With this in mind, this paper analyzes the concept of hybrid machining as a possible means of enhancing machining process sustainability by reducing power consumption, lead, and setup times. Two case studies are presented: turn-grind and mill-grind to illustrate the concept. The collected machining data have been used to correlate the energy consumption, CO2 emission, and cycle time for the two approaches used. The results from the presented case studies are promising as they show the benefits of the hybrid approach on energy consumption, CO2 emission, and cycle time.

Prediction of energy consumption and environmental implications for turning operation using finite element analysis

This article is concerned with the experimental and numerical investigation of energy consumption involved in the turning of Ti6Al4V titanium alloys. Energy consumption of a machining process is considered as an important machining performance indicator. This article aims to propose an approach for the prediction of energy consumption and related environmental implications using finite element modeling simulations. Machining experiments were conducted using uncoated carbide tools under dry cutting environment. DEFORM-3D software package was utilized to simulate finite element–based machining simulations. Experimental validation was mainly conducted by focusing on the cutting forces and power consumption measurements. Simulated results of the cutting force and power consumption were found in a good agreement with the experimental findings. The amount of CO2 emission resulting from energy consumption during the machining phase is highly dependent on the geographical location. This study also incorporated the energy mix of United Arab Emirates for the environmental calculations. Finally, in the light of proposed methodology, possible future directions and recommendations have also been presented.

Surface roughness and energy consumption analysis of conventional and peck drilling approaches

Drilling operations are one of the most commonly used operations in the automotive and aerospace sectors. The aim of this article is to compare peck drilling as an alternate approach to the conventional drilling and reaming operations; in terms of energy consumption and machined surface roughness to facilitate the selection of the optimum finishing processes with respect to machined surface quality and energy consumption. The experiments were performed under dry conditions on an Al-6061 using a high-speed steel reamer and drills of 12 mm diameter. The results revealed that peck drilling refined the surface finish of previously drilled steps in most of the cases. The outcome of the energy consumption analysis was used to evaluate the amount of CO2 emissions. The study suggested that surface roughness refinement in peck drilling was better than conventional drilling but was not as efficient as the reaming process. Peck drilling generated surfaces with a roughness value between those of drilling and reaming operations. Less tool wear was observed under peck drilling process when compared with conventional drilling. The investigation also revealed that CO2 emissions produced under peck drilling approach were slightly higher than for combined drilling and reaming approach.

An experimental analysis of energy consumption in milling strategies

Pocket milling operation is one of the widely used milling operations. CAM packages offer different tool path strategies to execute a machining operation. In the presented work zigzag, constant overlap spiral, parallel spiral and oneway tool path strategies were compared in terms of power and energy consumption for pocket milling of Al 6061 aluminum alloy. All pocketing operations were conducted using 8 mm diameter High Speed Steel (HSS) end milling cutters. Energy utilization was analysed for all tool path strategies. This work aims to develop better understanding towards sustainability concept in core machining phase.

Off line simulation system of machining processes

Abstract The primary objective for modeling of machining processes is to develop a predictive capability of machining performance in order to facilitate effective planning of machining operations. This capability leads to faster implementation, higher performance, quality at a lower cost. This comes about due to improved selection of machining parameters, optimal fixture design and the avoidance of tool failure. The simulation system presented simultaneously considers the effect of cutter geometry, the cutters initial position errors, workpiece geometry, machine tool dynamics, and workpiece/fixture system dynamics on the machining process. The integration of all of the above in one model provides an off-line tool to simulate and optimize the machining parameters and the fixture configuration cutting both lead and production time. The modular nature of the simulation system presented allows for the study of many different machining processes. The cutting forces in this system are modeled using a mechanistic approach. NURBS curves and surfaces are utilized for the geometric modeling and simulation of the machining process. While a finite element method is used to model and analyze the workpiece/fixture dynamics. Two case studies are presented to demonstrate the practical application of the presented simulation. The first case presents the optimization of the fixture configuration of a generic automotive component. While the second case presents the results of simulations performed on a novel mill/grind machining process. This process is a combination of face milling and grinding in one operation. Some simulated results are presented along with experimental validation.

Fatigue Life Prediction of Different Fiber-Reinforced Composites Using Polynomial Classifiers

Polynomial classifiers (PC) have already been shown to produce good fatigue life prediction for a specific composite under a variety of fatigue loading conditions. In this study, polynomial classifiers are used to predict the fatigue life in other composite materials not used in training. Different composite materials with a variety of fiber orientation angles are considered. The predictions obtained using PC are compared with the experimental results and are shown to be promising.

A finite element based energy consumption analysis for machining AISI 1045 carbon steel using uncoated carbide tool

Abstract This study investigates the energy consumption involved in the machining of AISI 1045 steel using uncoated carbide tools. Energy utilised in the machining operation is termed as an important machining performance indicator that has direct influence on the greenhouse gas (GHG) emissions. The present study utilised finite element modelling (FEM) technique to compute energy consumption involved in the particular machining operation. The study also compliments the environmental implications resulting from the energy consumption. Numerical simulations were performed using Deform-2D software package. The simulated cutting forces were predicted and used further to compute power and energy consumption. Geographical location also has critical influence on the production of CO2 emissions resulting from energy consumption. The present study integrates the energy mix of United Arab Emirates for CO2 calculations.

Performance Evaluation of TiAlN-PVD Coated Inserts for Machining Ti-6Al-4V under Different Cooling Strategies

Titanium alloys are labeled as difficult to materials because of their low machinability rating. This paper presents an experimental study of machining Ti-6Al-4V under turning operation. All machining tests were conducted under dry, mist and flood cooling approaches by using a TiAlN coated carbide cutting inserts. All cutting experiments were conducted using high and low levels of cutting speeds and feed rates. The study compared surface finish of machined surface and flank wear at cutting edge under dry, mist and flood cooling approaches. Scanning electron microscopy was utilized to investigate the flank wear at cutting edge under various cooling approaches and cutting conditions. Investigation revealed that TiAlN coated carbides performed comparatively better at higher cutting speed.