Salman Pervaiz

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.

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.

A study on the effect of main process parameters of rotary ultrasonic machining for drilling BK7 glass

BK7 glass is an important engineering material with extensive applications in high-quality and precision transmissive optical components. However, BK7 glass is considered to be a difficult-to-cut material due to its high brittleness and nonconductivity. This article presents the use of rotary ultrasonic machining process for drilling holes in BK7 glass. No previous reports have been found in the literature to experimentally investigate the response of the BK7 glass to rotary ultrasonic drilling. The experimental investigations take into account the effect of the key rotary ultrasonic machining input parameters including the ultrasonic power, spindle speed and feed rate on the output responses of cutting force, exit chipping, surface roughness, hole cylindricity and overcut errors, and surface integrity. The results show that the input parameters within the current ranges can significantly affect the quality of the drilled holes. Moreover, the selected level of any input parameter has the ability to significantly affect the influence of the other input parameters on the output responses. Through proper selection of input parameters, holes could be drilled in BK7 glass with less fractured topography, low surface roughness (1.32 µm), low exit chipping size (0.85), and very low cylindricity (3 µm) and overcut (73.6 µm) errors.

Sustainability assessment of shielded metal arc welding (SMAW) process

Shielded metal arc welding (SMAW) process is one of the most commonly employed material joining processes utilized in the various industrial sectors such as marine, ship-building, automotive, aerospace, construction and petrochemicals etc. The increasing pressure on manufacturing sector wants the welding process to be sustainable in nature. The SMAW process incorporates several types of inputs and output streams. The sustainability concerns associated with SMAW process are linked with the various input and output streams such as electrical energy requirement, input material consumptions, slag formation, fumes emission and hazardous working conditions associated with the human health and occupational safety. To enhance the environmental performance of the SMAW welding process, there is a need to characterize the sustainability for the SMAW process under the broad framework of sustainability. Most of the available literature focuses on the technical and economic aspects of the welding process, however the environmental and social aspects are rarely addressed. The study reviews SMAW process with respect to the triple bottom line (economic, environmental and social) sustainability approach. Finally, the study concluded recommendations towards achieving economical and sustainable SMAW welding process.

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.

Hole quality assessment in peck drilling

This paper evaluates the hole quality on Al 6061 aluminum alloy using peck drilling process. Specimens were drilled under dry conditions with HSS drill of 10 mm diameter. Peck drilling experiments were conducted in three steps of 10 mm each. Hole quality is checked by measuring the roughness (Ra) of generated surfaces. This roughness analysis indicates that new step in peck drilling has strong influence on surface roughness of previously drilled step. This work also suggests that step length and no of steps are important influential factors for surface roughness in peck drilling.