Advances in Industrial and Manufacturing Engineering最新文献

Additive manufacturing (AM) is a promising technology for designing complex metallic pieces for different sectors with resource and time effectiveness. Titanium (Ti) is an essential critical material for AM development. AM can produce intricate and cost-effective components with Ti alloys for the transportation sector which would not be possible with conventional manufacturing (CM) technologies. This study assesses the impact of AM on the life cycle of Ti and its alloys by using review (numerical data, case examples) and dynamics simulation modelling. This article quantifies potential environmental benefits and examines aspects related to using Ti alloys in the automotive and aerospace industries. Mass flow, energy consumption and related greenhouse gas (GHG) emissions are assessed by making a comparison between subcategories of AM including binder jetting (BJT), directed energy deposition (DED), electron beam-based powder bed fusion (EB-PBF), and laser-based powder bed fusion (L-PBF) and CM processes including forging, milling, machining, and die casting. The results show that the AM subcategories considered potentially reduce manufacturing phase energy consumption and GHG emissions except for L-PBF. The findings highlight that an inclusive consideration of all life cycle phases is needed to fully identify potential benefits of AM for industries. Also, the scenario analysis in this study proposes the opportunity for saving mass and minimizing energy consumption and GHG emissions by optimizing the structural design and manufacturing processes for Ti components.

Some of the key issues with AWJ technology are high roughness, low depth of smooth zone, and grit embedment. When compared to the unsubmerged AWJ, the submerged AWJ gives less divergence and produces higher energy at the cross section of the jet. Hence, this study examined the effects of pressure, traverse rate, and standoff distance on roughness, depth of smooth zone, and grit embedment in both AWJ conditions. Here, single factor experiments are conducted for experimental investigation wherein one factor is varied and the others are kept constant. In comparison, the submerged AWJ gave significant improvement in the roughness and depth of the smooth zone at lower levels of pressure (150 and 200 MPa), higher levels of traverse rate (300 and 350 mm/min) and standoff distance (4, 5 and 6 mm). The significant difference in grit embedment was observed at lower levels of traverse rate (150 and 200 mm/min), higher levels of pressure (300 and 350 MPa), and all the levels of standoff distance (2, 3, 4, 5, and 6 mm). The grit embedment in the submerged condition was lower due to the removal of initially embedded grits due to flushing action produced by cavitation initiation.

This paper is focused on wire-arc additive manufacturing and has a twofold objective. First, to deliver an overall state-of-the-art review of the different aspects of modelling. Second, to provide a detailed analysis of the macro-scale finite element modelling. The methodology draws from the fundamentals of the macro, meso and micro-scale modelling of the process, to the main strategies and objectives behind the development of analytical, statistical, machine learning and finite element analyses of macro-scale modelling. The intention is to provide information on the pre-processing requirements, solution techniques and results that are currently being worked on by some of the leading researchers in the field. This will enable readers to understand the main challenges, relevance, and assumptions of the different published works. The theoretical and numerical aspects are intentionally kept in a clear and understandable level so that users of finite element computer programs having the know-how on wire-arc additive manufacturing can bridge the actual gap to the developers of the programs.

In deep hole machining operations with twist drills, whirling vibrations lead to a significant increase in hole diameter deviation and circularity error. In this article, a nonlinear physical model with special consideration of the contact area between the margins of the tool and the workpiece is developed to predict the hole circularity of drilling operations. Numerical simulations are used to study the geometry of the drilling tool to propose a new margin design. In an experimental study, it is shown that the newly developed margin geometry for twist drill tools decreases radial vibrations and leads to a significant improvement in hole diameter deviations and hole circularities.

The present study explores a combination of numerical and simulation approaches to generate a process map for identifying the regimes of conduction and keyhole modes of melting and verify the same with experimental data. Finite Element based simulation studies were conducted to determine the regions of conduction mode, keyhole mode, and transition by varying the laser power and speed. Single tracks and density cubes were processed based on the simulation results to confirm the melting modes and study its effect on microstructure and hardness. Increase in volumetric energy density (VED) causes a shift in microstructure of single tracks, from a mix of short columnar and equiaxed grains in conduction mode to long columnar grains in keyhole mode, with an overall increase in the grain size. The melt pool depth to width ratio also increases with VED. The VED based criteria alone cannot determine melting modes as the single-track samples at 81 J/mm³ exhibited both conduction mode (at 250 W) and keyhole mode (at 350 W). Almost all the printed cubes showed high density (>99.9%) irrespective of melting mode. Similar to single track the average grain size of bulk samples increased with increase in VED. The bulk samples were subjected to three different heat treatments (Homogenisation, Solution treatment and Direct Double Aging) to study their effect on the microstructures and mechanical properties. Homogenisation resulted in near identical equiaxed microstructure irrespective of processing parameters. The highest hardness of about 470 HV was observed for the direct double aged samples.

Cutting fluids have a known negative impact on productivity, human health, and the environment in the manufacturing sector. A suitable method for reducing the effect of cutting fluids on human health and the environment is minimum quantity lubrication (MQL). In this experiment, AISI 1039 steel was machined using vegetable oil lubricant and MQL. A chemical method was used to extract vegetable oil from palm kernel seeds. Then, using established techniques, the physicochemical and lubricity properties of palm kernel oil (PKO) were ascertained. The Taguchi L₉ (3³) orthogonal array served as the basis for the planning of the experimental design. Process parameters such as surface roughness, chip thickness ratio, cutting temperature, and material removal rate were measured during the turning operations. The multi-response outputs from TGRA were considered to simultaneously optimize the cutting parameters namely depth of cut, feed rate, and spindle speed. At a temperature of 55°C, 180 min, and particle sizes of 0.2–0.5 mm, an oil yield of 55% by weight was obtained. The viscosity at 40°C, specific gravity, pour, fire, cloud, and flash points of the raw PKO were 117.6 mm²/s, 0.8940 mg/ml, 21°C, 231°C, 22.3 $°C$ and 227°C, respectively. The surface roughness and cutting temperature of PKO improved by 44% and 12%, respectively, when compared with mineral oil. The findings of this research confirmed the effectiveness of the integrated Taguchi-grey relational analysis (TGRA) optimization method and established an experimental foundation for the use of PKO minimum quantity lubrication turning.

The use of Field Assisted Sintering Technology (FAST) is examined for the consolidation of an advanced Ni-based superalloy powder feedstock. FAST processed material was directly compared to a benchmark material prepared via hot isostatic pressing (HIP) where it was found that density, hardness values and microstructures were comparable. FAST enables the retainment of the prior particle grain morphology when using sintering dwell times ranging from 10 to 240 min. The application of dwell temperatures above the γ′ solvus of the alloy resulted in significant grain growth. Measured densities reveal that the applied load and dwell time used during sintering have minimal effect on the final density of the consolidated material. The crystallographic texture was also shown to be isotropic in FAST consolidated material. This study demonstrates that FAST is potentially a viable complementary and/or alternative processing route for consolidating Ni-based superalloy powders.

Recent advances in robotic assisted-additive manufacturing (RA-AM) have enabled rapid material extrusion-based processing with comprehensive data collection. The following study investigates the adhesion dynamics of the initial printed layer across parameters such as surface energies, stand-off heights, and extrusion speeds of up to 100 mm/s, using an applied in-situ thermal analysis technique. Observations indicate that the characteristic length parameter, $L_c$ < 0.05 mm, is adequate in anchoring the thermal melt, which adheres to the substrate when the nozzle proximity to the surface increases. Up to 100% molten area is contacting the surface prior to translation, and a final eccentricity over 0.85 has been observed. Through an analysis of variance, operational parameters of lower nozzle heights, printing speeds, and higher surface energy were statistically significant. The resultant in-situ characterization-driven data, was used to train a convolutional neural network (CNN). The model tested at an accuracy of 90.9%, and was able to distinguish between failed prints and initially adhered structures.

Flow-drill screwing is one of the key joining technologies for car body structures in multi-material lightweight design. In the course of technological developments and subsequent volume production of a product, different assets are used to obtain the same joints, assuming that similar processes yield the same joint characteristics. Since a simple transfer of the process parameters for joining the same materials is usually not possible, a remarkable experimental effort is required to meet manufacturing requirements. In this study the transition to an enhanced flow-drill screwing system and its effects on the joint is investigated. For this purpose, two flow-drill screwing systems typically used in the automotive industry are considered. An application-oriented approach for determining the joining parameters is shown. First, the optimal joining parameters for the target system were determined based on the process curves and parameters of the initial system by fulfilling the requirements for the joint. The joints were evaluated by using cross sections and single-lap shear tests. On this basis, the results of both flow-drill screwing systems were compared. Due to the further development of the flow-drill screwing system the process times can be significantly shortened while achieving the same mechanical properties and better process control at the same time.

In this paper, to have control over geometry specifications of rectangular bar-shaped layers in a robotic concrete 3D printing process, a real-time vision-based control framework is developed and proposed. The proposed control system is able to set the layer-width by automatically adjusting the velocity of an industrial manipulator during the 3D printing process of concrete based materials relying on a vision system feedback. Initially, details related to the control system, vision and processing units, and robotic platform are discussed. In continue, technical descriptions related to the printhead design, conversion process from a digital 3D drawing model to numerical motion control commands of an industrial manipulator and building material used in this work are reported. The reliability and responsiveness of the developed system is then evaluated through experimental tests by printing several single bar-shaped layers with different wideness by means of an unique printhead geometry and also by printing two layers with the same dimension centrally above another. Overall, the high accuracy and responsiveness of the developed system demonstrate a great potential for real-time vision-based control of industrial manipulators for layer-width setting in concrete 3D printing applications.