Suitable Process Parameters Research Articles

Preparation of Polycarbazole and Polyaniline Conducting Thin Films and Coating on Indium Tin Oxide by Spin Coating, Dip Coating and Drop Casting

Conducting polymers such as polyaniline (PANI), polycarbazole (PC) and polythiophene (PT) have gained attraction among researchers owing to their outstanding electrical and optical properties. In present study, polyaniline (PANI), polycarbazole (PC) and polythiophene (PT) were prepared by oxidative chemical polymerization followed by their characterization using techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and Raman spectroscopy. The synthesized polymers were further coated with indium tin oxide (ITO) using three different methods viz. spin coating, dip coating and drop casting. The thickness of the films was measured using a Stylus Profilometer and found to be 400 nm for PC and 500 nm for PANI and PT. Therefore, it can be concluded that using suitable process parameters, thin films can be easily obtained from conducting polymers, thus opening new avenues in their application towards sensors, supercapacitors and optoelectronic devices.

Examination of the Impact of suitable Process Parameters on the Cold Extrusion of AA5754

Examination of the Impact of suitable Process Parameters on the Cold Extrusion of AA5754

Gas-rigid-flexible compound blade coupling enhanced experimental study on chaotic mixing of multiphase flow

Efficient fluid mixing is essential for process intensification. This study proposes a new method in which gas-rigid-flexible composite blades are coupled to enhance chaotic mixing in multiphase flow systems. The rigidity and flexibility of the blades were adjusted by intermittent gas injection, which increased the effectiveness of mixing of the liquid-liquid two-phase fluid. This study investigates the influence of different process parameters on the mixing efficiency and quantifies the chaotic characteristics of fluid mixing through pressure-time series analysis of multiscale entropy and the 0–1 test. A high-speed camera recorded the bubble movement in the flow field, while particle image velocimetry (PIV) revealed the enhancement of the properties of the flow field in the system due to the suspended motion of the particles. Using suitable process parameters, gas-rigid-flexible composite blade coupling significantly enhanced the mixing effect, where the mixing time of the G-RFCP system was reduced by 1.42 times compared to that of the CP system. Bubble motion, deformation, and rupture enhanced the mechanical agitation, increasing the intensity of the turbulence and chaotic behaviour. Flow-field analysis indicated a three-fold increase in the vorticity and a 1.04-fold increase in the velocity difference for the G-RFCP system compared with those of the CP system. This study provides theoretical and experimental foundations for understanding chaotic mixing in liquid-liquid two-phase fluids.

Ultrasonic Influence on Macrostructure and Mechanical Properties of Friction Stir Welded Joints of Al/Mg Sheets with 2 mm Thickness.

Friction stir welding (FSW) and ultrasonic vibration enhanced FSW (UVeFSW) experiments were conducted by using 6061-T6 Al alloy and AZ31B-H24 Mg alloy sheets of thickness 2 mm. The suitable process parameters windows were obtained for the butt joining of Al/Mg sheets. The effect of ultrasonic vibration on the macrostructure and mechanical properties of the dissimilar joints was studied. The results showed that the width of the weld nugget zone (WNZ) was enlarged to some extent and the hardness distribution in WNZ was more uniform in UVeFSW. In addition, the application of ultrasonic vibration effectively promoted the interpenetration degree of dissimilar materials in the WNZ so that the mechanical interlocking on the bonding interface of dissimilar Al/Mg materials was enhanced. The facture positions were changed from the bonding interface in FSW to the boundary between WNZ and the thermo-mechanical affected zone, and the ductile fracture zone was expanded. The highest ultimate tensile strength was 205 MPa at the process parameters set of 1200 rpm-50 mm/min in UVeFSW in this experiment. The average ultimate tensile strength of FSW/UVeFSW joints was 172.3 MPa and 184.4 MPa, respectively, and the average ultimate tensile strength was increased by 7.02% with the introduction of ultrasonic vibration.

Surface quality and microstructure evolution in fused silica under SF6/Ar reactive ion beam etching

The SF6/Ar reactive ion beam etching (RIBE) was proposed to explore the evolution of surface quality, subsurface defects, surface molecular structure, and chemical composition of fused silica. Also, the mechanism of reactive ion beam etching of fused silica surfaces was discussed. The results show that RIBE can maintain the original surface roughness by choosing suitable process parameters. this etching process can suppress the replication and expansion of subsurface defects and the deposition of reactants without bringing obvious contamination. The concentration of structural defects reaches a minimum at an etching depth of about 2 μm. However, further etching may lead to an increase in the chemical structure defects on the surface. The evolution of the intrinsic ring structure demonstrates that most intrinsic defects tend to reorganize into short (Si-O) ring structures. The etching mechanisms of Ar ions were discussed by simulating the stopping power and energy deposition. Phonon dissipation through atomic displacements and atomic vibrations is an important way of energy loss. Phonon vibrations and atomic dislocations induced by nuclear collisions are not only important factors causing the enhancement of electron-phonon coupling but also important causes of surface structural defects. The researches provide a theoretical basis for in-depth understanding of fused silica surface defect repair.

Revealing Subsurface Damage Morphology and Patterns in areal Ultrashort Pulse Laser Machining of Glass

Material removal rates as well as surface and subsurface quality are key aspects for the industrial application of ultrashort pulse (USP) laser machining. However, revealing so-called subsurface damage (SSD) is challenging. The presented study visualizes and quantifies subsurface damage patterns in areal USP laser ablation of fused silica (FS) and glass N-BK7 (BK). For the first time, using high-resolution optical coherence tomography (OCT) as non-destructive and three-dimensional (3D) evaluation method, SSD morphologies of areal laser machining induced damages are analysed. Influences of laser wavelength, beam geometry and processed material are investigated. Discovered differences of damage morphologies and depth in FS and BK point out the relevance of selecting suitable process parameters. Based on the evaluation of volumetric OCT data, the authors were able to quantify damage morphologies using the surface texture ratio as well as power spectral density functions. One important finding for the quantification and comparability of damage depths in USP laser processing is the influence of applicable evaluation thresholds. In comparison to area thresholds of 0.001% being applicable to OCT measurements, more lenient thresholds of e.g. 1% commonly applied in destructive SSD measurement methods in average result in a reduction of measured damage depths by a factor of ~ 2. This potentially leads to an underestimation of damage depths depending on methods on thresholds used. The presented measurement and evaluation methods as well as gained process insights are important assets for the future optimization of low-damage USP laser micromachining of brittle materials. Moreover, the general applicability and relevance of OCT-based morphological damage analysis in laser material processing is shown.

Predicting hardness of graphene-added Si3N4 using machine learning: A data-driven approach

This study presents a data-driven framework based on machine learning (ML) using extreme gradient boosting (XGBoost) for predicting the hardness of silicon nitride (Si3N4) ceramics reinforced with graphene. The XGBoost model takes into account various factors such as graphene type and content, characteristics of the raw Si3N4 powder, the parameters of the sintering process (sintering technique, temperature, pressure, holding time), and the characteristics of the sintered samples, i.e., the density, αβ content and Vickers hardness. The parameters that influence the Si3N4 hardness most strongly are identified, with sintering pressure, sintering time and density being the most influential. The addition of graphene content up to a certain threshold (1 wt%) has a positive impact on hardness. However, beyond that it leads to a lower density and a lower mechanical performance. Sintering parameters, particularly the sintering pressure, temperature, holding time and technique, strongly affect the density, final grain size, αβ Si3N4 composition and subsequently the hardness. The study highlights the importance of density and the densification process in achieving high hardness in Si3N4 ceramics. The developed ML model provides a valuable tool for predicting the hardness of Si3N4+graphene ceramics composites and offers insights into selecting suitable graphene type, content, and processing parameters. While the study primarily focuses on Si3N4+graphene composites, this novel approach holds promise for the in-silico design and analysis of diverse ceramic materials.

Optimization of Processing Parameters for Continuous Microwave Drying of Crab Apple Slices via Response Surface Methodology.

To improve product quality and obtain suitable processing parameters for crab apple slices (CASs) produced by continuous microwave drying (CMD), the effects of processing parameters, including slice thickness, microwave power, air velocity, and conveyor belt speed, on the evaluation indexes in terms of temperature, moisture content, color (L*, a*, b*), hardness, brittleness, and total phenolic content of CASs were investigated via the response surface method. The results indicated that microwave power has the greatest effect on the evaluation indexes applied to the CASs under CMD, followed by air velocity, slice thickness, and conveyor belt speed. To produce the desired product quality, the appropriate parameters for CMD of CASs were optimized as 1.25 mm slice thickness, 14,630 W microwave power, 0.50 m·s-1 air velocity, and 0.33 m·min-1 conveyor belt speed. Following that, the moisture content under CMD was found to be 13.53%, the desired color, hardness 0.79 g, brittleness 12.97 (number of peaks), and the total phenolic content 5.48 mg·g-1. This research provides a theoretical framework for optimizing the processing parameters of CASs using the response surface method.

Microstructure and mechanical properties of IN718 on 42CrMo for repair applications by laser directed energy deposition

Laser Directed Energy Deposition (LDED) has gained significant attention as a promising additive manufacturing technology for the repair and restoration of worn parts. The objective of this study is to assess the feasibility and performance of repairing 42CrMo substrates using Inconel 718(IN718) powder. In this study, the LDED process was employed to investigate the influence of varying laser power, scanning speed, and feed rate on a single track study. The optimal process parameters for trapezoidal groove repair were determined by comparing and evaluating factors such as dilution, aspect ratio, track continuity, and molten pool shape. Furthermore, the effects of different repair strategies (X-, Y-, Cross-paths) on the microstructure and mechanical properties were investigated. The results indicate that by using suitable process parameters, successful deposition of IN718 on 42CrMo is achieved. The investigation reveals elemental diffusion between the two materials, quenching phase transition on the substrate surface, and the formation of intermetallic compounds in the fusion zone. The fusion zone(FZ) and heat-affected zone(HAZ) exhibited the highest microhardness compared to the substrate. Significant changes in molten pool shape and arrangement were observed using different repair strategies, while the effect on grain size was not significant. Due to the high directionality of the samples fabricated using the LDED process, the samples of the X-path demonstrated the highest ultimate tensile strength and elongation compared to the other two repair strategies. The ultimate tensile strength after repair is comparable to that of the substrate, while the elongation is reduced.

Influence of Excitation Parameters on Finishing Characteristics in Magnetorheological Finishing for 6063 Aluminum Alloy.

The present work is aimed at studying the effects of the magnetorheological finishing process, using a low-frequency alternating magnetic field, on the finishing performance of 6063 aluminum alloy. The study investigates the influence of key excitation parameters such as current, frequency, excitation gap, and iron powder diameter on the material removal and surface roughness (Ra) of the finished workpiece by experiments. This study employs a single-factor experimental method, and the finish surface is analyzed by a Zigo non-contact white light interferometer. The magnetic field strength in the processing area increases with the increase in the excitation current and decreases with the increase in the excitation gap. When the current frequency is set to 1 Hz, the circulation and renewal of abrasives in the magnetic cluster is most sufficient, resulting in the optimal surface roughness value for the workpiece. According to the experimental results of the excitation parameters, more suitable process parameters were selected for a two-stage finishing experiment. The surface roughness of 6063 aluminum alloy was improved from 285 nm to 3.54 nm. Experimental results highlighted that the magnetorheological finishing using a low-frequency alternating magnetic field is a potential technique for obtaining nano-scale finishing of the 6063 aluminum alloy.

Research on the welding process of Q355ND thick plate with narrow gap double wire submerged arc welding

Abstract Aiming at the problems of low welding efficiency and unstable quality of thick plates of marine equipment in offshore deep-water areas represented by offshore wind power, the high-efficiency welding process of narrow-gap double-wire submerged arc welding of 30 mm thick Q355ND low alloy high-strength steel plate was developed by selecting the suitable welding material and welding process parameters. The results show that the welded joint has a beautiful appearance, well-fused sides, and no defects. The structure of the heat-affected zone of the joint is mainly composed of pro eutectoid ferrite, acicular ferrite, bainite, and a small amount of pearlite. The center of the seam is composed of a large amount of massive ferrite and a small amount of bainite. The average tensile strength of the joint reaches 536.5 Mpa, and the average impact energy of the weld center at -20°C reaches 48.4 J. The average impact energy of the heat-affected zone reaches 164 J. All physical and chemical performance tests meet the standard requirements. The development of welding processes has important practical significance for improving production efficiency and product quality. It will be widely used to construct offshore wind power towers, offshore platform jackets, and other offshore deep-water engineering equipment.

Preparation and characterization of zirconium carbide nano powder by hydrothermal and carbothermal reduction methods

A hydrothermal method was employed to synthesize the precursor of nano-zirconium carbide, which was subsequently heat treated at high temperatures under vacuum to obtain finely dispersed nanometer-sized zirconium carbide powder through a carbothermic reduction reaction. Scanning Electron Microscopy (SEM) was utilized to examine the microstructure of the precursors obtained under different hydrothermal conditions and carbon contents. The effects of different heat treatment temperatures on the microstructure of the products were analyzed. Transmission Electron Microscopy (TEM) confirmed the boundary coating structure of the hydrothermal precursor and provided insights into the phase structure of the nanometer-sized zirconium carbide. The reaction mechanism and temperature involved in the carbothermic reaction process were determined through calculations. Furthermore, the energy, phase and microstructure of the reaction were investigated using Thermogravimetric Analysis (TG-DSC) and X-ray Diffraction (XRD) at different temperatures. The obtained results revealed that the zirconium carbide precursor was synthesized via the hydrothermal method exhibited a core-shell structure with a boundary coating, which not only ensured uniform contact between C and ZrO2 particles but also facilitated the formation of zirconium carbide. The results show that the most suitable process parameters are Zr/C 1: 7, 240 °C and 24 h. The thermodynamic calculation results show that ZrO2 combines with carbon to form CO and ZrC when the temperature reaches 1656.56 °C. As the temperature rises, CO reacts with ZrO2 to form ZrC and CO2. TG-DSC shows that the carbothermal reduction reaction starts at 1100 °C and reaches its peak at 1418 °C. XRD analysis confirms that when the temperature reached 1450 °C ZrC appeared. At 1600 °C, the phase transition of ZrC is basically completed. TEM images showed that the synthesized zirconium carbide particles were about 30 nm.

Simulation of process forces and topographical characteristics of single grains in microfinishing processes

Honing operations, e.g. microfinishing, are resulting in high quality surfaces with a roughness values, e.g., average roughness Ra, of only a few micro- to nanometer [1]. The simulation of honing processes can be beneficial to reduce experimental effort in terms of determining suitable process parameters for such processes. Various aspects of the finishing process can be investigated with the aid of process models, such as tool wear, tool life, the resulting surface quality or shape deviation. In addition, process simulations can be used to assist in the design of components with regard to desired functional properties. In order to model processes with such high accuracy, it is necessary to be aware of process influences on a microscropic scale. Such influences can be analyzed separately, for instance, by means of analogy experiments to reduce the complexity and dependencies of the occurring effects. In this work, a process force model was developed based on single-grain scratch tests, which takes into account the process-inherent kinematic variations. The occurring single grain forces in dependence of the orientation of the grains and in relation to the cutting direction were analyzed and modeled. This is important for a further analysis of the influences on tool wear to increase the accuracy of corresponding models.

Process parameters settings of friction stir welding using multi-response optimization for aluminum alloys

The defense and aerospace industries utilize the AA2050, an aluminum-lithium alloy of the third generation. Principal component analysis (PCA) and Taguchi-grey relational analysis (GRA) are utilized in this study to enhance the process constraints for friction stir welding (FSW). The quality of the weld can be influenced by various process factors such as the speed at which the weld is traversed, the speed at which the tool is rotated, the angle at which the tool is tilted, the diameter of the shoulder, and the shape of the tool pin. The combination of PCA and the well-known Taguchi-GRA approach enables the objective estimation of response weights. Here, a Taguchi L16 orthogonal array was designed, and sixteen tests were carried out using it. These experiments were conducted with various assessments including tensile strength, yield strength, elongation percentage, hardness of the weld zone, bending load, etc Through the utilization of Taguchi-GRA-PCA analysis, the most suitable process parameters were identified as a traverse speed (TS) of 160 mm min−1, a rotating speed (RS) of 900 rpm, a tilt angle (TA) of 2 degrees, a shoulder diameter (SD) of 16 mm, and with a straight square tool pin profile (TPP). ANOVA revealed the relevance of all five characteristics, with rotational speed being the most influential, accounting for 43.56% of the entire result. A confirmation experiment done under ideal conditions revealed a significant improvement in total weld quality of 19.06%.

Modelling and numerical analysis for rotatory friction welding of U75V steel rails

This article presents a rotatory friction welding (RFW) method for U75V steel rail, aiming to mitigate challenges related to property discrepancies between the as-welded joints and the rail base metal (BM) and to narrow the heat-affected zone (HAZ) in conventional flash-butt welding (FBW) joints. A rotational intermediate plate is designed for rails with non-axisymmetric cross-sections, necessitating stationary during RFW. Advantages include achieving a relatively uniform welding heat input and maintaining the peak temperature of the contact interface near A1. To implement these concepts, a 2D finite element (FE) model for the RFW process of U75V rail steel rods was established and validated through experiments with identical process parameters. Microstructure predictions derived from continuous cooling transformation diagram confirm that ferrite microstructure is formed near A1 through rail steel RFW. Subsequently, a 3D FE model for intermediate plate RFW steel rails is developed to explore appropriate process parameter combinations. A suitable process parameters combination was identified, ensuring the peak temperature of the majority model contact interface does not exceed A1, resulting in a 76.7% reduction in HAZ (from ∼50 to 11.66 mm), and axial shortening of 8.10 mm, a significant decrease compared to the usual burn-off (30–40 mm) during FBW. These findings underscore the efficacy of this innovative welding solution and emphasize the significance of simulation technology in process optimization.

Real-Time Monitoring of Thermal Phenomena during Femtosecond Ablation of Bone Tissue for Process Control.

Femtosecond (fs) laser technology is currently being considered in innovative fields such as osteotomy and treatment of hard tissue thanks to the achievable high resolution and ability to prevent tissue damage. In a previous study, suitable process parameters were obtained to achieve competitive ablation rates on pork femur processing. Nevertheless, a better control of thermal accumulation in the tissue during laser ablation could further improve the postoperative regeneration of the treated bone compared with conventional procedures and push forward the exploitation of such technology. This study presents methods for real time analyses of bone tissue temperature and composition during fs laser ablation and highlights the importance of implementing an efficient cooling method of bone tissue in order to achieve optimized results. Results show that it is possible to achieve a larger process window for bone tissue ablation where bone tissue temperature remains within the protein denaturation temperature in water-based processing environment. This is a key outcome towards a clinical exploitation of the presented technology, where higher process throughputs are necessary. The effects of process parameters and environments on bone tissue were confirmed by LIBS technique, which proved to be an efficient method by which to record real-time variation of bone tissue composition during laser irradiation.

Optimization and GRA prediction of Al–Cu pulsed laser welding process based on RSM

In this paper, the process parameters of pulsed laser welding of Al–Cu are studied using response surface methodology (RSM) and grey relation analysis (GRA) to propose optimal directions for lap-shear strength of the joints. A single-factor experiment was conducted to find the suitable process parameter windows. The RSM models were established and analyzed with laser power, welding speed, pulse width, and frequency as inputs and joint lap shear, interfacial weld width, and weld-penetration-depth as outputs. With the use of GRA of interfacial weld width and weld penetration depth with the lap-shear force of joints, the improved direction for the lap-shear force of joints can be proposed.

A new magnetic enhanced chemical mechanical polishing method for quartz glass slender holes

Due to the limitations of tool size, field assisted polishing methods are often employed for polishing the internal surfaces of slender holes with large aspect ratios. However, in existing polishing methods, fields are often applied in isolation, which limits the ability to obtain high surface quality. Furthermore, it is rare for polishing method studies to fully leverage the advantages of multiple fields to create a synergistic effect. Therefore, developing a polishing method that harnesses the synergistic interaction of multiple fields, and revealing the polishing mechanism, is crucial for achieving high-quality internal surfaces of quartz slender holes. To address this problem, a novel magnetic enhanced chemical mechanical polishing method was proposed in this paper and a systematic process study was carried out to analyze the synergistic effects of magnetic and chemical fields. To evaluate the effects of process parameters on material removal and forecast MRR, the material removal process was modeled and validated based on the consistency between experimental and theoretical values. Suitable process parameters are determined through experiments and analysis on magnetic field distribution and process parameters. By conducting EDS mapping and XPS analyses on the reaction product, the enhancement mechanism of magnetic field on material removal in the chemical mechanical polishing process was identified. Under the assistance of a magnetic field, the magnetic abrasive particles encircle the CeO2 particles to fully contact the workpiece surface. The contact force between the polishing tool and the workpiece surface increase. Both of the effects promote the chemical reaction and enable the reaction layer on the surface to be removed in time to obtain higher surface quality. As a result, this method achieves high-efficiency and high-quality polishing, significantly reducing the surface roughness Sa of slender holes from 0.3 μm to 77 nm, with a material removal rate of 141 μm/h.

Research on the forming and demolding process of shape memory self-demolding mold

The molding method is highly anticipated in engineering fields and has been preliminarily applied. However, traditional demolding methods introduce subtle deviations in demolding direction, leading to demolding defects and reduced forming accuracy. To address this, we developed an innovative Shape Memory Polymer (SMP) mold. Through finite element simulation, we extensively investigated the effects of diaminodiphenylmethane (DDM) addition, temperature, and load on the template forming and shape recovery processes. Finally, we experimentally verified the feasibility of the self-demolding of the template. The findings demonstrate that as the amount of DDM added increases, the glass transition temperature of SMP progressively elevates. This can be attributed to the enhanced crosslinking triggered by the addition of DDM. Consequently, during the stage of preserving shape in mold formation, SMP exhibits a heightened storage modulus and diminished shape recovery. Notably, when 1.5 g of DDM is added, the shape memory template exhibits the least shape recovery, with a shape retention rate of 78.2%. Conversely, employing 1.6 g of DDM generates the highest shape recovery but only achieves a shape retention rate of 59.5%. Augmenting the amount of DDM is advantageous in accomplishing template demolding. Higher temperatures expedite the initiation of the shape recovery process, facilitating template demolding during the shape recovery stage. Moreover, increasing the load can minimize template rebound and enhance the precision of mold formation. However, it also intensifies the complexity of self-demolding. Consequently, it is imperative to sensibly determine and implement suitable process parameters in applications.

Enhancing mechanical properties of selective-laser-melting TiN/AISI 420 composites through Taguchi GRA and PCA multi-response optimization

The enhancement of mechanical properties in martensitic AISI 420 stainless steel is realized through the incorporation of TiN ceramic particles using the selective laser melting (SLM) method. This study introduces an innovative hybrid mixing method designed to uniformly disperse TiN within the AISI 420 matrix, ensuring the absence of agglomerations and contaminations in the feedstock for the SLM process. Employing a combined approach involving the Taguchi method, Grey Relational Analysis, and Principle Component Analysis, optimal processing parameters and TiN content are identified, encompassing a laser power of 350 W, laser speed of 370 mm/s, hatch distance of 0.07 mm, layer thickness of 0.05 mm, and one percent by weight of TiN particles. The optimized SLM sample showcases exceptional characteristics with a hardness of 743 ± 20 HV, tensile strength of 1822 ± 21 MPa, and a modulus of toughness of 99.7 ± 3.0 J/m3, surpassing existing results. Introducing TiN particles into the AISI 420 matrix with suitable SLM processing parameters induces significant microstructural alterations, reinforcing the matrix and elevating the mechanical properties. These results mark a substantial advancement in metal matrix composite materials by applying cutting-edge manufacturing techniques.