Proper Selection Of Process Parameters Research Articles

Nitrogen alloyed austenitic Ni-free stainless steel for additive manufacturing

Nitrogen alloyed austenitic nickel-free stainless steel (ANFSS) is one of the most promising group of materials for consumer and healthcare products. They can be used to substitute not only conventional AISI 316L, but also more expensive titanium and Co-Cr alloys. Previously the utilization of nitrogen alloyed materials has been limited due to poor machinability resulting from high strength and ductility, and difficulties in manufacturing the nitrogen alloyed raw materials. Recent developments in powder metallurgy, for example, additive manufacturing (AM), offer feasible net shape manufacturing routes to go around machining and material related challenges. The present study investigates and introduces a viable processing route for an ANFSS by gas atomization, direct energy deposition (DED), and sintering. Special attention is paid to control the nitrogen content in different processing steps by investigating a Fe-16Mn-14Cr-0.27C-0.35N alloy with experimental and computational methods. The results show that the nitrogen content can be computationally estimated and maintained at desired level by proper selection of processing parameters, and thereby controlling the final nitrogen content of the ANFSS alloy.

Optimisation of processing parameters for wear properties of polylactic acid biopolymer parts in FDM process

ABSTRACT Currently, additive manufacturing (AM) technology has been expanding in advanced engineering and biomedical applications. The fused deposition modelling (FDMTM) method, also known as fused filament fabrication (FFF), is one of the most extensively used AM methods owing to its simple operation, reliability and potential to manufacture intricate components. The mechanical and wear properties of these components depend mainly on the proper selection of processing parameters. This study aims to determine the optimum parameters for low wear rate, less frictional force and good surface roughness. To achieve this aim, a hybrid approach based on user preference ranking is adopted to evaluate the effect of the four processing parameters including nozzle temperature, fill density, layer thickness and printing speed, on the wear behaviour, frictional force and surface roughness. The study procedure includes Taguchi L27 experiment design, finding the weight ratios, calculating utility index (UI) values and optimising UI values using Taguchi methodology for maximum utilisation. The results found that at 220°C of nozzle temperature, 100% fill density, 0.24 mm layer thickness and a printing speed of 60 mm/s are optimal parameters for the maximum utility index value. From the results, the percentage of contribution of fill density, nozzle temperature, layer thickness and printing speed were observed as 69.071%, 15.974%, 5.431% and 2.306%, respectively.

Characterization and modelling of the crystallization behavior of PEEK for polymer processing techniques

This study examines the crystallization behavior of high-performance thermoplastics under both isothermal and non-isothermal conditions. The accurate prediction of the crystallization kinetics in conjunction with process simulation tools can create new methods for defining the key process parameters in various polymer processing techniques. By simulating the thermal history of the materials, optimal process parameters can be assigned at specific time points, resulting in a more homogeneous process and improved material properties, while avoiding costly and time-consuming trial-and-error experimentation or post-processing. Here, flash differential scanning calorimetry (DSC) was used to capture the rapid crystallization of Luvocom 3F PEEK 9581 NT, and various isothermal and non-isothermal models were applied to mimic its crystallization behavior, highlighting the differential form of the dual Nakamura model as the most suitable option. To accurately predict the absolute crystallinity, the maximum achievable enthalpy was introduced in the model, and weight factors were assigned to the primary and secondary crystallization mechanisms. The differential form of the model is suitable for efficient implementation in process simulation tools, because it is independent of the total crystallization time. This research has the potential to significantly improve the selection of proper process parameters in complex polymer processing techniques, e.g., material extrusion.

Microwave processing of stone fruits before juice extraction

This article explores the possibility of using microwave processing technology to improve the process of extracting juice from stone fruits. The authors conducted experiments to determine the optimal microwave processing parameters, such as power, processing time and frequency, for each of the considered fruits. The effects of fruit temperature, humidity and initial sugar content on processing efficiency were also studied. The obtained results showed that the treatment with microwave energy before extracting the juice helps to increase the yield of juice and reduce the content of solid residues in the juice. The process of extracting juice from stone fruits can be improved through the use of microwave processing technology, which is an effective method. This is of practical importance for juice producers and consumers, who can receive a better and healthier product. The article also discusses the parameters of microwave processing, such as the power and time of exposure to waves, as well as the temperature of the raw material. Proper selection of processing parameters allows you to achieve the best results in terms of yield and quality of juice. In general, the use of microwave processing of stone fruits before juice extraction is an effective way to increase the yield and improve the quality of the juice. Choosing the right processing parameters is crucial to achieve the best results, as it is necessary to take into account the characteristics of each type of fruit.

Comparative evaluation and sensitivity analysis of multi-modelling and optimization of milling Ti–6Al–4V alloy with high-pressure coolant jets

An effective cooling method with the proper selection of process parameters can intensify the machining performance by reducing the loss of resources with better quality products. In this regard, modelling is an appropriate way of predicting responses in changing environment and optimization is an efficient tool of selecting the best process parameters based on the specific desire. With a view to enhance the machinability of Ti–6Al–4V alloy, the first attempt of the current study was to predict the performance characteristics of milling such as cutting force (N), specific cutting energy (J/mm3) and surface roughness (μm) with the variation of speed (m/min), feed (mm/min), depth of cut (mm) and cooling approach by developing mathematical models. For the present work, three different predictive models such as response surface methodology (RSM), artificial neural network (ANN), and adaptive neuro fuzzy inference system (ANFIS) was followed. Additionally, a comparative assessment of the used predictive models was carried out and ANFIS was noticed as the most accurate predictive model. After that, optimization of the selected responses was conducted by multiple-objective optimization on the basis of ratio analysis (MOORA) method where the relative weights of each response were defined by principal component analysis (PCA). For milling Ti–6Al–4V alloy within the specific boundary conditions, PCA-MOORA suggested an optimal parameter setting at 32 m/min speed, 22 mm/min feed rate, and 0.75 mm depth of cut with rotary high-pressure cooling. Finally, the sensitivity of the used MOORA method with the variation of unitary ratio was checked out to take a robust decision.

Additive Manufacturing of Titanium-Based Materials Using Electron Beam Wire 3D Printing Approach: Peculiarities, Advantages, and Prospects

Potential of additive manufacturing technologies, namely, xBeam 3D Metal Printing for the fabrication of uniform Ti–6Al–4V (Ti-6-4, mas.%) material as well as layered titanium-based structures, with mechanical properties sufficient for wide practical application is demonstrated. The key distinctive features of this process are titanium alloy wire as a feedstock material and hollow conical electron beam for heating and melting of the wire. 3D printed with special ‘shift strategy’ Ti-6-4 alloy meets requirements to mechanical characteristics of corresponding conventional cast and wrought products, if microstructure features, material anisotropy and crystallographic texture are controlled with proper selection of processing parameters. Production of multilayered materials consisting of combined layers of different titanium materials, viz. commercially pure titanium (CP-Ti), Ti-6-4 and high-strength T110 alloys, as well as metal matrix composites (MMC) based on Ti-6-4 matrix reinforced by fine TiC particles is considered. Microstructural features and mechanical properties of all 3D printed materials are investigated. Terminal ballistic tests are performed with different ammunition. Described results show the promising potential of 3D printing technologies, xBeam 3D Metal Printing as an example, for manufacturing of titanium-based multilayered armour materials with reduced thickness and weight, and at the same time, sufficient protection characteristics.

Support Vector Regression approach for prediction of delamination at entry and exit during drilling of GFRP Composites

The demand for Composites in the modern era have increased immensely due to its vast applications and superior properties over conventional materials. Glass Fibre Reinforced Plastic (GFRP) is one of the economic alternative to conventional engineering materials due to its high specific modulus of elasticity, high specific strength, good corrosion resistance, high fatigue strength and lightweight. Components made out from GFRP composites are usually near net shaped and require holes for assembly integration. Drilling is an important process as concentrated forces can cause major damage to the composite. Drilling of GFRP causes various damage such as thermal degradation, fibre breakage, matrix cracking and delamination. A substantial damage is caused by delamination which can occur both on the entry and exit sides of the composite, exit side delamination considered more severe. Therefore, selection of proper process parameters during drilling operation is very much essential. In the present work, a support vector regression (SVR) model is developed to predict the delamination at entry and exit during the drilling of GFRP composites. The model is developed based on the data obtained from experimentation. The model accuracy is evaluated by the three performance criteria including root mean square error (RMSE), Nash–Sutcliffe efficiency co-efficient (E) and co-efficient of determination (R2). The model provides an inexpensive and time saving alternative to study the delamination at entry and exit of the GFRP composite actual drilling operation.

Aggregation multiplicative rule for optimal parametric identification of electric discharge machined AA6061/Al2O3/10p composite

The effectiveness of any machining process depends significantly on the suitable selection of machining parameters that can aid in achieving the desired properties. This is a challenging task due to numerous conflicting performance measures. The need for a systematic and scientific tool is therefore apparent. To this end, the present research work explores the potential application of a novel appraisal mechanism in the form of aggregation multiplicative rule to appraise and identify the optimal processing condition for the electric discharge machining of AA6061/Al2O3/10p composite. The proper selection of process parameters in the electric discharge machining is essential to carry out the machining process with desired part tolerances, accuracy, and surface finish. In this connection, three input process parameters, viz., discharge current (Id), gap voltage (Vg), and discharge duration or pulse-on time (Ton), were considered. Their impact on the following output process parameters was investigated: material removal rate (MRR), wear ratio (WR), average surface roughness (Ra). Through the application of the aggregation multiplicative rule approach, it was revealed that the following input process parameters yielded the best output results for the electric discharge machining of AA6061/Al2O3/10p composite: Id (A) = 12 A, Vg (V) = 35 V and Ton (μs) = 200 μs.

Corrosion and tribological behaviour of Friction Stir Processed AA2024-T351 alloy

Abstract AA2024-T351, a heat treatable aluminum alloy, has a high strength to weight ratio and good fracture resistance and has application mainly in the aircraft and aerospace sector. However, the alloy is susceptible to high corrosion because of the secondary phases (Al2Cu) present in the matrix. With an objective to increase the corrosion and wear resistance, Friction Stir Processing is applied to engineer the morphology and dispersion of the Al2Cu phase in the alloy. The friction stir processing trials are performed by varying the tool rotation speed, tool traverse speed, and shoulder diameter, as the properties of the friction stir processed region depend on the proper selection of process parameters. A hybrid linear-radial basis function model is developed to explore the effect of tool rotation speed, tool traverse speed, and shoulder diameter on the grain size, microhardness, corrosion rate, wear rate, and corrosion potential of the friction stir processed AA2024-T351 alloy. The predominant corrosion mechanism and wear regimes in AA2024-T351 alloy are understood from the characterization study on the surface morphology and elemental analysis of the corroded and worn specimens. The optimum friction stir processing parameters that improve the grain refinement, microhardness, corrosion resistance and wear resistance of AA2024-T351 alloy are established.

Characterization of ultrafine-grained copper joints acquired by rotary friction welding

Copper rods with ultrafine-grained microstructure, obtained by multi-turn ECAP processing, were subjected to Direct Drive Rotary Friction Welding using various processing parameters, such as rotational speed and pressure, which resulted in different energy and heat input. Even though friction welding is a high energy process, by a proper selection of processing parameters it was possible to maintain grain size at around 0.7 µm in the weld zone and preserve the UFG microstructure. These microstructural features translated into mechanical properties: the YS for those specimens was around 330 MPa. Processing parameters that resulted in a larger heat input caused an increase in grain size to around 2 µm; this, however, increased ductility and led to a uniform elongation exceeding 5%. Corrosion resistance in the stir zone increased, as was evident in the higher open circuit potential and higher corrosion potential in comparison with base material; the observed differences were about 50 mV. These changes can be explained by the higher fraction of HAGBs in the SZ.

Characterization of Friction Stir and TIG Welded CK45 Carbon Steel.

The present paper aims to compare the microstructural and mechanical properties of CK45 carbon steel plates, joined by friction stir (FSW) and tungsten inert gas (TIG) welding methods. Besides visual inspection, the welded joints and the base material were subsequently evaluated in respect of optical microstructures, hardness and tensile properties. Sound joints could be accomplished using both the FSW and TIG welding methods through proper selection of process parameters and the filler metal. The influence of a water-cooling system on the FSW and various filler metals on the quality of TIG welding were further assessed. Both the FS welded sample as well as TIG welded samples with two different filler metals ER70S-6 and ER80S-B2 exhibited brittle behavior that could be mitigated through optimized water cooling and use of R60 filler metal. A drastic reduction of brittle martensite phase constituent in the microstructure corroborated significant improvements in mechanical properties of the welded zones for both the FSW sample as well as TIG welded samples with R60 filler metal.

Selective laser melting of Ti6Al4V alloy: Process parameters, defects and post-treatments

Selective laser melting (SLM) has received huge attention recently by the research community due to feasibility of realization of tailored intricate metallic structures having applications in biomedical, aviation and energy industries. SLM of Ti6Al4 V is found to be one of the most demandable and potential area. Present work is aimed for critical review of noteworthy contributions in terms of SLM process parameters, defects and various post processing techniques considered by various researchers. Proper selection of process parameters can arrest the tendency of defect generation and appropriate post treatment results in improvement in mechanical behavior in comparison with as-built SLMed Ti6Al4 V components. Efforts have been made to identify correlations between SLM parameters, specially scan speed, laser power, hatch spacing and layer thickness, with prominent defects. Different post processing approaches considered by important research studies have been extensively analyzed and their impact on defects and mechanical behavior especially fatigue performance and biocompatibility of SLM-fabricated Ti6Al4 V alloy is revealed. Many remedies have been identified in the form of optimization of process parameters and post processing techniques. The outcomes of work have clearly facilitated in developing a better scientific understanding of SLMed Ti6Al4V alloy and have also opened many dimensions for future investigations.

Laser-based additive manufacturing of a binary Ni-5 wt.%Nb alloy

In the present study, Ni95Nb5 (wt. %) alloy samples are additively manufactured using selective laser melting (SLM) as a surrogate for Ni-based superalloys. Near porosity-free samples are fabricated utilizing a simple analytical model to predict melt pool dimensions, guide process parameter selection, and determine the defect-free printability map in the process parameter space. Ni95Nb5 mechanical testing specimens displayed consistent yield strengths (∼600 MPa) and ultimate tensile strengths (∼750 MPa) across a range of process parameters. These results show that with the proper selection of process parameters, SLM can produce parts with consistent mechanical properties in a wide process parameter space in simple alloying systems.

Parametric optimization in drilling of GFRP composites using desirability function integrated simulated annealing approach

The present work focuses on parametric optimization during drilling of glass fibre reinforced polymer (GFRP) composites. GFRP composites have wide range of applications in the field of aerospace, defence, automobile and transportation industries. Drilling process is broadly used for GFRP composites since components made out from GFRP composites are usually near net shaped, thus requiring holes for assembly integration. Hence proper selection of process parameters during drilling of GFRP composites is essential. In order to study delamination in GFRP at entry and exit side of the laminate and surface roughness, experiments have been conducted using Taguchi’s experimental design with a view to reduce number of experimental runs. Cutting speed, feed rate and drill size are considered as three input parameters for drilling at four different levels. Drilling of GFRP is performed using a CNC milling machine under prefixed conditions. Taguchi’s approach fails to solve multi-response optimization problem. Therefore, desirability function approach is used to convert multi response into equivalent single response. Regression analysis has been used to develop the relationship between composite desirability index and input parameters, resulting a valid mathematical model. Finally, simulated algorithm is used to obtain the optimum parameter setting.

Eksperimentalna analiza zavarivanja trenjem korišćenjem ravnih igala kod AA2024-T3 limova

In friction stir welding, lesser tool life restricts the usage of non-circular pin in friction stir welding tool eventhough it delivers comparatively better weld joints than circular pin. Process peak temperature during the process affects the shear strength of the flowing material around the tool pin. Maintaining the process peak temperature as low as possible improves the properties in heat affected zone but on the other hand it increases the stress on the tool pin.Especially on the usage of non-circular pin, the pin surface experiences uneven stress distribution and causes premature tool failure. In this paper, optimum thermal environment through proper selection of process parameters and dwell period with respect to the pin geometry are analysed. A comparative analysis is also made to understand the impact of increase in flat surfaces in the pin surface on weld quality in the view of developing a suitable thermal environment that can improve tool life without compromising joint strength. Apart from this, optimum dwell period for the chosen tool pin geometry is analysed based on the empirical softening temperature of the material.

Polymer self-heating during incremental forming

• Polymer sheets are formed by Incremental Forming with the aid of frictional heating. • The temperature is controlled as a function of tool rotation and traveling speed. • The influence of the temperature on significant process features is investigated. • A thermo-mechanical numerical model is developed with a commercial FEM code. • A phenomenological model of the heat exchange is described. The study investigates the suitability of friction heating, generated by the forming tool rotation, to form polymer sheets during single-point incremental forming, and the possibility to control the temperature of the sheet by the selection of proper processing parameters. Polycarbonate sheets were formed to produce a square pyramid frustum geometry, varying the tool rotation speed and the traveling speed and monitoring the temperature. Load measurements were performed during the process, as well as the evaluation of the surface roughness and the elastic springback, to determine the influence of these processing conditions. Moreover, a thermo-mechanical numerical model was developed to understand the main phenomena involved. The results confirmed that the processing temperature, which increases with the tool rotation speed and decreases with the traveling speed, influences the sheet forming process and can be controlled by the selection of the processing speeds. A phenomenological model of the heat exchange was introduced to better explain the temperature evolution during the process and how it is influenced by the processing speeds.

An experimental investigation on energy-effective additive manufacturing of aluminum parts via process parameter selection

This paper investigates the influences of process parameters on part quality, electrical energy consumption, and corresponding energy effectiveness (EE) of AlSi10Mg specimens fabricated by selective laser melting (SLM). Here, EE is defined as the ratio between equivalent quality and specific energy consumption (SEC), where SEC refers to the energy consumption per kilogram of part produced during the building process. The reduction of electrical energy without significantly compromising quality via process parameter configuration was studied. Three parameters, laser power, scan speed and overlap rate, were selected and full factorial design was employed. Single track and single layer experiments were conducted to determine the ranges of process parameters, and multiple layer specimens were prepared for the testing of quality performances, including density, tensile strength, and hardness. The energy consumption of the auxiliary system and laser of the SLM machine were measured for SEC calculation. Results show that the density does not increase with increased SEC, while the tensile strength and hardness show increasing trends. EE can be improved without significantly sacrificing density and hardness, but the tensile strength will be greatly reduced. A case showed that a significant percentage (27.8%) of electrical energy could be saved while satisfying the quality requirements via proper selection of process parameters for the manufacturing of SLMed parts. The findings will help process designers to foster the sustainability of additive manufacturing.

The Use of Statistical Functions for the Selection of Laser Texturing Parameters

Abstract Laser surface texturing is currently the most developed technique for producing fully reproducible microcavities on the surfaces of machine elements. From the point of view of texture technology, an important aspect is the proper selection of process parameters to obtain texture elements with desirable and repetitive geometries and physicochemical properties. Surface texturing improves mottling and fretting resistance and is also used wherever the adhesion properties of surface layers (printing techniques, bonding materials, biological and chemical activity, coatings, etc.) are important. The article shows the possibility of applying statistical functions to the selection of appropriate machining parameters to obtain microgeometry useful in the application of textured surfaces [1].

Synthesis of graphene flakes using a non-thermal plasma based on magnetically stabilized gliding arc discharge

The use of non-thermal plasma at atmospheric pressure has emerged as a technique for the substrate-free, gas-phase synthesis of graphene nanoflakes (GNFs). In this paper, a non-thermal plasma based on magnetically stabilized gliding arc discharge (MSGAD) was employed to prepare GNFs. The effects of the carbon-containing precursor, plasma gas, and arc current on the GNFs synthesis were investigated. The technique produced GNFs with sizes of 50–200 nm and 1–20 layers, spherical carbon nanoparticles with 10–40 nm diameters, and graphitic particles. The results showed that the formation of GNFs depended on the selection of proper process parameters, such as precursors with a high H/C ratio, an Ar-N2 plasma gas, a low arc current, a low precursor flow rate, and a suitable plasma gas flow rate. Correlations between the process parameters and the product morphology indicated that abundant H atoms and fewer polycyclic aromatic hydrocarbons were favorable for the formation of GNFs.

Modeling and Optimization of Process Parameters for Laser Powder Bed Fusion of AlSi10Mg Alloy

Direct Metal Laser Sintering (DMLS) is a laser powder bed fusion process, grabs the attention of industries to make metal components directly from the metal powders. However, the quality of the build component depends on the sintering depth as well as sintering mechanism which are directly influenced by process parameters. Proper selection of process parameters to build the component is the key to the success of the DMLS process at commercial level. A common solution to make a quality component is to fuse the powder layers with maximum layered thickness, which can be achieved with appropriate selection of process parameters. In the present research, finite element simulations have been carried out to measure the sintering depth at different process parameters such as laser power, scan speed, porosity percentage, laser spot size, and powder bed thickness. Based on the predicted temperature field and sintering depth, an optimization model was developed by using response surface methodology with an aim to optimize the process parameters that improve the printing quality. The accuracy of the model was confirmed by using analysis of variance. From the optimization model, it is found that maximum sintering depth of 3 mm achieved with a laser power of 162 W, a scan speed of 156 mm/s, the percentage of porosity of 20%, a laser spot size of 0.2 mm, and the powder layer thickness of 1 mm respectively. This optimized model will help to design and control the process parameters for building quality components.