Amir Rashid

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.

Nanofluids: Properties, Applications and Sustainability Aspects in Materials Processing Technologies

Nanofluids could be used to provide cooling and lubrication action and to control thermo-physical and tribochemical properties of material processing. It is foreseen that properly designed nanofluids could surpass conventional cutting fluids with respect to thermal conductivity, convective heat transfer coefficient, critical heat flux, viscosity, and wettability. These properties have a promising potential to lead to the development of new coolants and lubricants with applications in a wide variety of materials processing technologies. This paper analyses the developments in research on the properties of nanofluids and evaluates their potential for applications in machining, focusing on their thermal and tribological aspects. The increasing use of nanofluids leads to a need for information on their sustainability in order to recognize and avoid risks. Sustainability is discussed in view of occupational health and safety and toxicity of nanoparticles.

Performance analysis of the closed loop supply chain

PurposeThe question of resource scarcity and emerging pressure of environmental legislations has brought a new challenge for the manufacturing industry. On the one hand, there is a huge population that demands a large quantity of commodities; on the other hand, these demands have to be met by minimum resources and pollution. Resource conservative manufacturing (ResCoM) is a proposed holistic concept to manage these challenges. The successful implementation of this concept requires cross functional collaboration among relevant fields, and among them, closed loop supply chain is an essential domain. The paper aims to highlight some misconceptions concerning the closed loop supply chain, to discuss different challenges, and in addition, to show how the proposed concept deals with those challenges through analysis of key performance indicators (KPI).MethodsThe work presented in this paper is mainly based on the literature review. The analysis of performance of the closed loop supply chain is done using system dynamics, and the Stella software has been used to do the simulation.FindingsThe results of the simulation depict that in ResCoM; the performance of the closed loop supply chain is much enhanced in terms of supply, demand, and other uncertainties involved. The results may particularly be interesting for industries involved in remanufacturing, researchers in the field of closed loop supply chain, and other relevant areas.OriginalityThe paper presented a novel research concept called ResCoM which is supported by system dynamics models of the closed loop supply chain to demonstrate the behavior of KPI in the closed loop supply chain.

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.

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.

Towards Circular Economy implementation: an agent-based simulation approach for business model changes

This paper introduces an agent-based approach to study customer behavior in terms of their acceptance of new business models in Circular Economy (CE) context. In a CE customers are perceived as integral part of the business and therefore customer acceptance of new business models becomes crucial as it determines the successful implementation of CE. However, tools or methods are missing to capture customer behavior to assess how customers will react if an organization introduces a new business model such as leasing or functional sales. The purpose of this research is to bring forward a quantitative analysis tool for identifying proper marketing and pricing strategies to obtain best fit demand behavior for the chosen new business model. This tool will support decision makers in determining the impact of introducing new (circular) business models. The model has been developed using an agent-based modeling approach which delivers results based on socio-demographic factors of a population and customers’ relative preferences of product attributes price, environmental friendliness and service-orientation. The implementation of the model has been tested using the practical business example of a washing machine. This research presents the first agent-based tool that can assess customer behavior and determine whether introduction of new business models will be accepted or not and how customer acceptance can be influenced to accelerate CE implementation. The tool integrates socio-demographic factors, product utility functions, social network structures and inter-agent communication in order to comprehensively describe behavior on individual customer level. In addition to the tool itself the results of this research indicates the need for systematic marketing strategies which emphasize CE value propositions in order to accelerate customer acceptance and shorten the transition time from linear to circular. Agent-based models are emphasized as highly capable to fill the gap between diffusion-based penetration of information and resulting behavior in the form of purchase decisions.

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.

Control of milling process dynamics through a mechatronic tool holder with purposely designed Joint Interface

Machine tool joints have significant influence on the dynamic characteristics of the machine tool and therefore on the response of the machining system to excitations from the cutting process. In cases of unstable response, generally described as chatter, surface quality of a machined work-piece and tool life deteriorate significantly. This paper presents a novel way of exploiting joints in order to control the dynamic response of the system, by integrating a mechatronic tool holder (Joint Interface Module - JIM) in the machine tool. This system has a purposely designed joint interface with controllable natural characteristics (stiffness and damping). These characteristics are controlled by altering the applied preload on the internal joint interface of the tool holder. The preload on the joint interface is controlled by pneumatic means. In doing so, a milling process during which the stability limit was exceeded became stable during the machining process, without alteration of the process parameters.

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.

Influence of rake angle on the cutting energy when modeling the machining of Ti6Al4V

The finite element based machining simulations have been used widely in industry and academia to analyze the machining process. These virtual machining simulations have advantages over the real machining experiments due to the immense potential of saving time and expenses. The simulation techniques are even more popular when machining difficult to cut materials such as titanium alloy (Ti6Al4V). In order to make machining process sustainable in nature, energy consumption during the cutting process should be optimized accordingly. The present study aims to provide an insight towards the relation of cutting energy with respect to the different cutting tool geometries. The study used finite element based simulations to investigate the effect of rake angle on the cutting energy. Based on the cutting energy outcomes different suggestions were made to minimize the cutting energy.