Conventional Machining Processes Research Articles

Investigation of Cryogenically Treated Physical Vapor Deposition TiAlN/NbN-Coated Carbide Inserts in End Milling of Hard Titanium Alloy

Abstract Cryogenic-treated inserts (CTIs) are playing a vital role in the significant improvement of tool life and the enhancement of mechanical properties of the cutting tools during conventional machining process. This work addressed the upshot of cryogenic treatment of physical vapor deposition TiAlN/NbN-coated carbide insert on the machinability of a Ti-6Al-4V alloy workpiece. It is weighed in terms of surface roughness, chip morphology, and tool wear in the cutting tool insert. Surface roughness was measured by a noncontact type 3-D laser scan microscope system. The observed average surface roughness in CTI reduction is between 13 and 32 % over that of the untreated insert (UTI) machining condition. The multisurface chip characteristics of free surface and back surface were identified and broken down by scanning electron microscopy. The experimental results demonstrated that the favorable chips and the reduction in tool wear were better achieved under the CTI machining condition than under the UTI machining condition.

Studying the Performance of Cutting Carbon Fibre-Reinforced Plastic Using an Abrasive Water Jet Technique

In recent years, composite materials such as carbon-fibre-reinforced plastic (CFRP) have been widely used in medical devices, industries, marine and aerospace applications due to their high resistance-to-weight ratio toughness, corrosion resistance, and other novel properties. The machining of these composite materials using conventional machines results in poor precision and surface finishing due to excess heat generation at the tool-material contact zone. The drawbacks of the conventional machining process can be overcome with the adoption of a novel cutting technique using pressurized water, which can dissipate the heat generated by the impact of abrasive particles against the material in order to eliminate the poor precision and surface finishing caused by overheating. In this experimental study, the performance of surface quality (roughness and kerf angle) of CFRP machining using an abrasive water jet technique has been studied for a wide range of cutting parameters, such as water pressure and cutting speed.

A Finite Element Study of Large Strain Extrusion Machining Using Modified Zerilli–Armstrong Constitutive Relation

Abstract The objective of this work is to study the performance of modified Zerilli–Armstrong constitutive relation proposed in our previous study for the finite element modeling of a severe plastic deformation technique called large strain extrusion machining. The modified Zerilli–Armstrong constitutive relation is implemented in a finite element model of large strain extrusion machining of Inconel 718 to analyze the influence of process parameters, i.e., the chip compression ratio and tool–chip friction, on deformation, effective strain distribution, and hydrostatic pressure distribution along the extruded chip. The predicted strain values for different chip compression ratios were validated by comparison with those obtained through an analytical model. The finite element predictions also served as a guideline in designing the large strain extrusion-machining setup on which experiments were conducted to generate Inconel 718 foils with superior mechanical properties. The predicted limits of chip compression ratio were in close agreement with experimentally realizable values. Furthermore, the predicted strain distribution through the thickness of the chip was validated with the results of hardness measurement tests. Microstructural characterization of the Inconel 718 foils was carried out by using both optical and transmission-electron microscopic studies in order to reveal the presence of fine-grain structures. The validations showed the effectiveness of the modified Zerilli–Armstrong constitutive relation in modeling large strain extrusion machining—a variant of the conventional machining process.

Machinability of Titanium alloy 6242 by AWJM through Taguchi method

Titanium alloy is difficult to machining in the conventional machining process. Hybrid production technology for abrasive water jet machining (AWJM) allows the machining of all engineering applications. This paper explores the optimization of the process variables of Titanium alloy AWJM (Ti- 6Al- 2Sn- 4Zr- 2Mo). The AWJM process parameters such as water jet strength, traverse speed, and standoff distance were studied against the material removal rate, surface roughness, kerf angle. The contribution of this parameter to responses has been calculated by variance analysis. For material removal rate, surface roughness, kerf angle, regression models were obtained.

Minimum Quantity Lubrication-Alternative to Flood Cutting and Dry Cutting

For any machining process cutting tool temperature, surface roughness value of work piece, cutting forces are the performance deciding parameters. These parameters directly, indirectly affect the tool life and thus affect machine cycle time, product cost and productivity. Cutting fluids are used to improve the machining performance however its cost and environment unfriendliness raise several questions. Researchers have documented several adverse health and environment effects of cutting fluids through their work. Plenty are efforts are going on to reduce the cutting fluid costs and to minimize its harmful effect to the environment. There is urgent need to provide sustainable, low cost and productive alternative to conventional machining processes. Minimum quantity lubrication is emerging as a tool to minimize the quantity exposure to the cutting fluids. In present work, low cost minimum quantity lubrication is used to verify its performance in terms of temperature, cutting forces and surface roughness. Results are compared for dry, flood and MQL cutting. Performance of MQL is better as compared to dry and flood cutting.

Finite element analysis of the slot milling of carbon fiber reinforced polymer composites

Carbon Fiber Reinforced Polymer (CFRP) composites are widely used for making the components and primary structures in the field of aircraft, aerospace, automobile, medical, construction and many essential items which we use every day. These composite laminates are light in weight without compromising its strength. Hence, CFRP composites attract the researchers and the modern industries to investigate more on it. Industries rely on conventional machining process to achieve required shape and size, but CFRP composites show intrinsic behaviour while machining because of its non homogeneous properties. Selecting the appropriate tool and the cutting conditions for machining the CFRP composite, influences more in achieving the desired shape, size with close tolerance. In this paper, a 3D Finite Element Model is developed to simulate the slot milling process and to predict the cutting forces for the different cutting conditions. The reliability and accuracy of 3D FE analysis depend on the friction coefficient and failure model used in the FE model. These FE input parameters were applied in a wider range and analysis was carried out. The cutting forces obtained from the FE results are correlated with the experimental results to validate and to evaluate the influence of the FEM parameters. The outcome of this investigation is to suggest a suitable Failure model and the Friction coefficient, which ensures the reliability of the FE Model.

Influence of Abrasive Water Jet Machining Parameters on Hybrid Polymer Composite

In this current research study, the holes are drilled in the hybrid composite reinforced with Ni–P-coated glass fiber (GF) and Al2O3 nanowires via abrasive water jet (AWJ) machining process. The input process parameters such as jet pressure, traverse speed, and concentration of abrasive on the delamination characteristic both at the inlet and at the exit sides of the drilled holes are investigated and optimized for the minimum delamination and fiber pullouts. The experiments are conducted using Taguchi’s L25 orthogonal arrays, and the input process parameters are optimized for lesser delamination at both sides together by grey relational analysis. From the experimental results, it is clear that the abrasive flow rate has significantly effect on the delamination characteristics followed by abrasive water jet pressure and the traverse speed. Grey relational technique is used for optimizing multiple responses (delamination at the inlet and exit) simultaneously. The morphological analysis was been carried out using scanning electron microscope (SEM) to determine the wall quality of the drilled holes. From the experimental analysis, it was found that the machined surfaces were free from delamination to an extent at optimized conditions (the mass flow rate of 350 gm/min, jet pressure of 3000 Bar and traverse speed of 800 mm/min, respectively), which leads to minimal delamination both at the entry and at exit side of the machined hole as compared with the holes drilled by conventional machining process.

Performance evaluation of AE-pulse of wire EDM process on Ti-10V-2Fe-3Al alloy by Taguchi GRA technique

Titanium alloy, Ti-10V-2Fe-3Al is one of the recently developed materials having special characteristics of deep hardenability, ductility, fracture toughness including high strength to weight ratio. But, titanium alloys have poor machinability due to the formation of built-up edges and tool wear in conventional machining processes. Wire electrical discharge machining wire EDM is found to be the most preferred machining process among other non-traditional processes for cutting of the difficult-to-cut materials. The surface integrity aspects of the machined component play a crucial role in the functional performance of the component. The performance of an advanced AE-pulse (Anti Electrolysis Equi-energy) over E-pulse on surface integrity aspects in the wire EDM process is studied in detail. Experiments were carried with various levels of pulse-on-time, pulse-off-time, peak current setting, and servo voltage through a Taguchi L9 orthogonal array. The responses such as kerf width, surface roughness, material removal rate, and white layer thickness were studied through gray relational analysis (GRA) technique. The optimized results were validated through experimental studies. It is observed that the optimized process parameter values were Ton: 12 μs Toff:40μs IP No.:10 SV:10V, which gave 28 % of the significant reduction of white layer thickness, 16% improvement of MRR, 5% reduction of surface roughness, and 4% of reduction of kerf width.

Determination of Multi-performance Characteristics in Electric Discharge Machining of DIN 1.2767 Steel Using Grey Relational Analysis


 Electric discharge machining (EDM) is one of the most important unconventional machining processes, which can cut hard materials and complex shapes that are difficult to machine by conventional machining processes easily and with high accuracy. In this study, L18 orthogonal array combined with gray relational analysis (GRA) is implemented to investigate the multiple performances characteristics in EDM of DIN 1.2767 Tool Steel. Machining process parameters selected were discharge current (Ip), pulse-on time (Ton), pulse-off time (Toff), and electrode material (copper alloys [NSS and B2]). The investigated performances characteristics were tool wear rate (TWR) and material removal rate (MRR). Analysis of variance (ANOVA) and Taguchi’s signal-to-noise ratio with the help of Minitab-17 software were used to analysis the effect of the process parameters on TWR and MRR. The experimental results and data analysis reveal that TWR and MRR are more affected by Ip and Ton. The minimum TWR was obtained at parametric combination Ip (6A), Ton (800 μs), and Toff (800 μs) and the maximum MRR attained at Ip (25A), Ton (800 μs), Toff (200 μs), and NSS electrode. After applying GRA, the optimal parametric combination for MRR and TWR was determined as Ip (25A), Ton (800 μs), Toff (200 μs), and NSS electrode. The study also exhibited the occurrence of an interaction between the variables on the responses. In addition, scanning electron microscopy images showed that the metal surface was affected with the increase in Ton and Toff.

Multiple-objective optimization of hydroxyapatite-added EDM technique for processing of 316L-steel

ABSTRACT Fabrication of the 316 L steel with moderate surface roughness (SR) and thin recast layer (RLT) is very difficult using both the conventional and non-traditional machining processes. Due to the stochastic behavior of electro-discharge machining (EDM) process, the machining performances significantly rely on the system variables. This research work aims to investigate the influences of EDM method variables on the machining performances during the machining of 316 L steel. Another goal is to minimize the performances by applying nano-hydroxyapatite (HA) particles in the EDM-Oil. Moreover, the optimal solutions for processing of 316 L through the NSGA-II method are proposed in this research. Followed by the pulse-on time and HA amount, ANOVA study reports peak current being the most important parameter for the responses such RLT and SR. The augment of peak current, HA amount, and pulse-on time result comparatively lower RLT and SR than the previous studies. The best 7 solutions selected from the predicted 120 solutions following the objectives are proposed generating the Pareto frontiers. Less than 10% of the validation tests errors confirm the high accuracy of the predicted solutions. The present research proposed a potential and cost-effective method for processing of 316 L steel.

Surface modification of tool steel by using EDM green powder metallurgy electrodes

Electro-discharge machining (EDM) is mostly used for machining difficult-to-cut materials which are difficult to machine by conventional machining processes. In recent years, EDM is also used for surface modification. This work aims to investigate the phenomenon of surface modification of tool steel Calmax (Uddeholm) by EDM process using Cu-ZrO2 powder metallurgy green compact electrode. Results show that the higher Material Transfer Rate of 46.5 mgr/min is achieved on the combination of Ip=9A and Ton=25 μs. The effect of peak current and pulse duration on the material transfer rate and surface roughness (Ra and Rz) was investigated. Machined surfaces were characterized by scanning electron microscopy (SEM).

Effect of process parameters on material removal rate in magnetic abrasive flow machining of Al/SiC/B4C metal matrix composites

In the recent times, the necessity for magnetic abrasive flow machining (MAFM) process in the industry arises as it is superior to conventional machining processes. MAFM is used to obtain high surface finishing and materials removal rate for the cylindrical, complex and intricate profiles. In this paper, the effect of process parameters has been studied on the material removal rate in MAFM process of metal matrix composites of Al/SiC/B4C prepared by stir casting process. The process parameters are magnetic field, extrusion pressure, no. of cycles, mesh size of abrasives, workpiece material and concentration of abrasives.Taguchi design of experiments has been used for design of experiments and the analysis of variance technique has been used to check the significance level of each input parameter. The results show that the intensity of magnetic field has a dominant effect on the material removal rate.

Influence of fillers on polymeric composite during conventional machining processes: a review

Nowadays, polymeric composites have emerged as a material highly in demand for advanced structures in various sectors, such as automotive, aerospace, and marine industries, due to their specific mechanical and physical properties. Functional efficiency of these composites significantly depends on their machinability. This encouraged the researchers to present a wide study and research work on polymeric composite. The present paper reviews the research progress on conventional machining of different filler-loaded polymeric composites. It delves into integrated functions in terms of its mechanism and machining responses. This includes aspects such as various weight percentage of filler on the machining responses. It also shows the proper filler loading for the improvement of mechanical properties (i.e., strength and stiffness) and fracture toughness for both intralaminar and interlaminar perspectives. Machining procedure and performance capabilities have been reviewed and depicted in detail as well. A comprehensive summary of the findings along with future perspectives has been included at the end, which might contribute to a greater development of this machining process in the future.

Influence of Feed Rate Response (FRR) on Chip Formation in Micro and Macro Machining of Al Alloy

In this paper, the investigation of chip formation of aluminum alloy in different machining strategies (i.e., micro and macro cutting) is performed to develop a holistic view of the chip formation phenomenon. The study of chip morphology is useful to understand the mechanics of surface generation in machining. Experiments were carried out to evaluate the feed rate response (FRR) in both ultra-precision micro and conventional macro machining processes. A comprehensive study was carried out to explore the material removal mechanics with both experimental findings and theoretical insights. The results of the variation of chip morphology showed the dependence on feed rate in orthogonal turning. The transformation of discontinuous to continuous chip production—a remarkable phenomenon in micro machining—has been identified for the conventional macro machining of Al alloy. This is validated by the surface crevice formation in the transition region. Variation of the surface morphology confirms the phenomenology (transformation mechanics) of chip formation.

Unconventional Machining of ceramic matrix Composites – A review

With an increase in demand for materials that are lightweight, thermally stable, and can sustain higher temperatures, ceramic matrix composites or CMC’s turned out to be potential candidates however, the major challenge with these materials was the manufacturing aspect and so, there was a demand for machining methods which could easily machine these materials without having much tool wear, provide higher material removal rate (MRR), and produce low surface roughness. Conventional machining (CM) processes like milling, grinding, drilling, and so on were turning out to be disadvantageous as the hardness of these materials is high and it results in excessive tool wear, high surface roughness, and low MRR. Recent researches in unconventional machining processes such as laser machining, plasma machining, electric discharge machining, and abrasive water jet machining, etc. are showing positive results when compared with CM. The current work presents a review of the unconventional machining process of these difficult to machine materials. The unconventional machining processes considered here are the laser-assisted machining process, rotatory ultrasonic machining process, and abrasive water jet machining process. Furthermore, it also discusses how these machining processes are better than conventional machining processes and it compares their MRR, surface roughness (SR), change in the properties, and also discusses the effect of these machining processes on the same parameters.

Comparative study of parametric effects on the performance of simple and powder mixed EDM using aluminium and graphite powder on Inconel X750 alloy

In the present scenario, Electrical Discharge Machining (EDM) is one of the most entrenched non-conventional machining processes which are widely used in different manufacturing sectors worldwide. Generally, the conductive materials, which having geometrically complex shape and extremely difficult to machine by conventional machining processes are machined by EDM. The further improvement of the machining efficiency of this EDM process may be enhanced by using powder suspended dielectric fluid which is called Powder Mixed EDM (PMEDM) process. In this research work, an attempt has been made to analyze the comparative study of parametric effects on the performance characteristics like material removal rate (MRR), tool wear rate (TWR) and surface roughness (SR) in terms of average value of roughness parameter (Ra) of simple (without powder) and powder mixed EDM using Aluminium (Al) and Graphite powder on Inconel X750 alloy by experimental investigation. Here, in our study, Peak current (Ip) pulse on time (Ton) and pulse off time (Toff) have been taken as the variable process parameters and concentration of powder (Cp) is taken as 6 g/l in all cases throughout the experimentation. From the experimental results, it has been observed that PMEDM gives lower MRR but better surface finish in comparison with conventional EDM technique (without powder). Also, it has been noticed that graphite powder mixed EDM is more effective for getting better surface finish of Inconel X750 alloy compared to Al mixed PMEDM process.

Experimental investigation on electrical discharge machining of steel H13

Abstract Electrical Discharge Machining (EDM) is being used to machine components made out of hard alloys and are geometrically complex in shapes. Different types of materials like tool steels, composites, carbides and super alloys are difficult to machine by conventional machining process can be machined by EDM. But this process still has some limitations during machining of hard alloys like tool steel (H13). This material finds application in various types of industries such as tool and die, nuclear and aerospace etc. In this research paper, simultaneous optimization of output parameters over cut and material removal rate is done using desirability approach. Orthogonal array (L18) design was used to perform the EDM experiment on H 13 steel.

AllFactory: An Aquaponics 4.0 Transdisciplinary Educational and Applied Research Learning Factory at the University of Alberta

Learning factories have presented an effective environment to develop theoretical and practical knowledge and skills, especially in engineering and technologies. It supports many of the challenges that engineering education faces regarding teaching, training, skills development, and learning novel technologies brought by the Industry 4.0 paradigm. However, most current learning factories focus on conventional manufacturing environments, i.e., CNC machining, additive manufacturing, or assembly processes, limiting the impact of the learning factory concept in engineering education and transdisciplinary areas focusing on the frontiers between sciences and engineering. This paper introduces the 'AllFactory' (Aquaponics 4.0 Learning Factory) developed at the University of Alberta, focusing on transdisciplinary engineering problems and Industry 4.0 implementation in vertical indoor farming (known as Aquaponics 4.0). The elements, systems, processes, and technology used are presented and the expected research, education and learning, and future training outcomes.

Traditional and non-traditional machining of nickel-based superalloys: A brief review

As nickel-based superalloys have heat and oxidation resisting capability, there are numerous applications of it in the field of marine and aerospace. This paper focuses on the review of traditional and non-traditional machining processes implemented for nickel-based superalloys over the past decade. The challenges faced during the implementation of conventional machining processes and the application areas in which nickel-based superalloys used have also been discussed. Most commonly used nickel-based alloys for a variety of applications and studies are presented. The consolidated information about the implementation of these machining processes for nickel-based superalloys is listed, and the paper concludes with some key findings and gaps about the machining of nickel-based superalloys.

A review on the challenges in machining of ceramics

Ceramics are solid compounds largely consisting of inorganic and non-metallic components bound by strong ionic and/or covalent bonds. Advanced ceramics such as Zirconia, Silicon carbide, Alumina and Silicon Nitride, find extensive applications in the field of aerospace, military and defence industry due to their enhanced mechanical and physical properties such as excellent refractoriness, high compressive strength, chemical inertness and hardness. While such properties are highly desirable in extreme environments, the inherent high brittleness and low shear strength poses a significant challenge to their machinability. Machining of ceramics is also plagued by surface damage, excessive tool wear, and edge chipping when machined using conventional techniques; non-conventional techniques such as Electric Discharge Machining (EDM) and Abrasive Water Jet machining are characterized by poor surface finish and excessive occurrence of pits, respectively. Achieving dimensional accuracy and minimizing collateral damage such as surface cracks are the key challenges in the machining of ceramics. In this review work, the machining parameters significantly influencing the machining of ceramics using non-conventional processes such as, Ultrasonic machining and Laser machining have been discussed. In contact type of non-conventional machining, feed rate significantly affects the surface finish while in the non-contact type laser scan speed seems to be deciding input parameter in machining ceramics. Rotary Ultrasonic Machining and Laser Assisted Machining (LAM) seem to be the most popular techniques for machining of ceramics, mainly due to better metal removal rate and almost defect-free surface compared to the conventional machining processes.