Performance Of Manufacturing Process Research Articles

Understanding the sustainability potential of part consolidation design supported by additive manufacturing

The environmental performance of additive manufacturing (AM) processes and the produced parts has gained increasing interest. Various assessment models have been developed based on the general life cycle assessment (LCA) framework, although different in goals and boundaries, the inputs for these models are always a single part (or a batch of same parts). In contrast, the present research provides a new perspective towards the selection of a more sustainable assembly design. A comparative LCA model is built to investigate the environmental performance difference of two design approaches: assembly design (AD) made via conventional manufacturing (CM) plus assembly operations and part consolidation (PC) made via AM plus machining. The effects of weight reduction, prolonged life expectancy, and improved functional performance (e.g. fuel efficiency) attainable in the PC routine and the advantages of replaceable subcomponents in the AD routine are studied in a throttle pedal assembly example throughout the lifespan of the vehicle. The results reveal that the PC routine can be more environmental friendly than the AD counterpart when the lifespan can be improved by over 200% or the weight savings are more than 30%. The role of functional performance improvement on affecting sustainability may depend on the part/vehicle ratio and vehicle types. This article extends the literature on sustainable assembly design and the proposed LCA model provides a way of identifying the profitable margins of PC in the early design stage.

Manufacturing and performance of a novel self‐centring damper with shape memory alloy ring springs for seismic resilience

This paper discusses the manufacturing process and mechanical performance of a novel self-centring damper equipped with a group of kernel elements, namely, shape memory alloy (SMA) ring springs. The study commences with an experimental investigation on individual SMA ring spring specimens, enabling a fundamental understanding of their working principle and mechanical performance. Some technical issues related to manufacturing process, low-temperature heat treatment (annealing), quenching, and cyclic training are also discussed. Subsequently, the fabrication steps and working mechanism of the dampers incorporating the SMA ring springs are elaborated, and a further experimental study on a large-scale prototype damper specimen is carried out. The test results show that the damper specimen exhibits satisfactory mechanical behaviour with a stable flag-shaped load–displacement hysteretic response. A high initial stiffness and an adequate level of “yield” resistance are exhibited due to a relatively high preload applied to the SMA ring spring group. Excellent self-centring capability with no residual displacement is observed, and satisfactory energy dissipation with an equivalent viscous damping ratio of up to 18.5% is shown. No failure to any component of the damper is observed by the end of the test. The proposed damper is expected to resist strong earthquakes and offer self-centring driving action effectively for engineering structures without the need for repair.

GENERATING CONTEXTUAL DESIGN FOR ENVIRONMENT PRINCIPLES IN SUSTAINABLE MANUFACTURING USING VISUAL ANALYTICS.

Design for Environment (DfE) principles are helpful for integrating manufacturing-specific environmental sustainability considerations into product and process design. However, such principles are often overly general, static, and disconnected from production contexts. This paper proposes a visual analytics-based framework for generating DfE principles that are contextualized to specific production setups. These principles are generated through interactive visual exploration of design and process parameters as well as manufacturing process performance metrics corresponding to the production setup. We also develop a formal schema for aiding storage, updating, and reuse of the generated DfE principles. In this schema, each DfE principle is associated with corresponding product lifecycle data and the evidence that led to the generation of that principle. We demonstrate the proposed visual analytics framework using data from an industry-led experiment that compared dry ice based and oil based milling for a specific production setup.

Effects of interface properties on the mechanical properties of bio-inspired cellulose nanocrystal (CNC)-based materials

Cellulose nanocrystals (CNCs) is a new family of cellulose materials with outstanding mechanical and chemical properties that have been successfully demonstrated to have potential for many applications. Understanding the mechanical behavior of individual CNCs and their interaction at nanoscale is very important for improving the manufacturing process and mechanical performance of the resulting materials at macroscale. However, due to time and length scale limitations for both, experimental observations and atomistic modeling, predicting the mechanical performance of a system consisting of many CNCs is still challenging. We present a coarse-grained model of CNCs based on both mechanical properties and crystal-crystal interactions to overcome this limitation. Parametrization of the model is carried out in comparison with all-atom (AA) molecular dynamics and experimental results of some specific mechanical and interfacial tests. Subsequently, verification is done with other independent tests. In particular, we note that the parameters of the model can be calibrated to capture the properties of both twisted and untwisted CNC interface without sacrificing the mechanical properties of the individual particle. Finally, we analyze the effect of interface properties on the mechanical performance of CNC-based materials including, bending test of a crystalline bundle, tensile test and fracture in two representative bioinspired architectures. The results revealed different failure mechanisms depending upon the interfacial configuration. For instance, well-aligned CNCs lead to a more brittle and catastrophic failure mechanism, whereas naturally twisted interfaces promote toughening mechanisms that helps attained optimal mechanical performance.

Establishing prediction models for feeding power and material drilling power to support sustainable machining

Analyzing and modeling the power and energy consumption of machining processes have been considered to be an important approach to enhance the energy performance of manufacturing process. As drilling process is one of the most commonly used technologies in manufacturing, specialized research on the modeling method of material drilling power of drilling is very rare. The predictive accuracies of existing models for feeding power and material drilling power have great potential for improving. To fill this gap, improved predictive models of feeding power and material drilling power of drilling process are proposed in this research. To show the feasibility of the proposed modeling methods of feeding power and material drilling power, extensive experimental studies were carried out on a machining center. The research results show that the predictive accuracies are generally improved by 1–2% with the established feeding power model in this article compared with the existing model. Moreover, the predictive accuracies of all the tested drilling cases by using the established material drilling power model are above 90.0%, and a high average accuracy of 95.0% is achieved. The established power models of drilling process in this research build a good basis for modeling of total drilling power and energy optimization.

Environmental performance of additive manufacturing process – an overview

PurposeThe purpose of this paper is to overview the literature about the environmental performance of additive manufacturing (AM) and to evaluate the use of life cycle assessment (LCA) on these studies.Design/methodology/approachThis study was based on the systematic literature review.FindingsThe investigation found that most authors were concerned about the energy consumption of the AM equipment, which is the subject studied by 87% of articles. In addition, 25% of the studies used LCA at least in some level, making a global environment assessment to evaluate the environmental impacts of AM. By analyzing research studies, it was possible to find signs that AM could be a lower environmental impact process, when compared with traditional manufacturing. However, this assumption is not valid in all cases because there are many variables that may affect environmental results.Originality/valueDue to the increase on the usage of this type of technology by industries, studies on the environmental performance of this process became relevant.

Characterizing the influence of resource-energy-exergy factors on the environmental performance of additive manufacturing systems

Additive manufacturing is rapidly emerging as an alternative to conventional manufacturing, including subtractive processes, often attributed to its claim for sustainable product development, e.g., reduced cost, reduced energy and material use, and the distributed production of tailored consumer products. However, many of these benefits remain unsubstantiated for large-scale production. The aim of the research herein is to identify and characterize the factors influencing the systemic environmental performance of additive manufacturing as an end use of energy, using exergy analysis and life cycle assessment. These methods have been previously applied to evaluate the environmental performance of conventional and non-conventional manufacturing processes, and offer a validated approach to explore the environmental impacts of additive manufacturing with respect to systemic material and energy losses. In this study, the environmental impacts of direct metal laser sintering (DMLS) of iron metal powder and fused deposition modeling (FDM) of acrylonitrile styrene acrylate polymer filament are characterized by performing a thermodynamic (exergy) analysis of the resources and energy utilized and lost from cradle to gate. It is found that only 10% of total DMLS process inputs contribute to material processing, while 90% of the inputs are lost as bulk waste, heat, and work. For FDM, it is found that only 7% of total process inputs contribute to material processing, while 93% are lost. Following the exergy analysis, life cycle assessment is performed to characterize the environmental impacts of the exergy losses using single-issue indicator (Global Warming Potential, GWP) and aggregate indicator (ReCiPe 2008) methods. The results show that electricity consumption is a key contributor to both focal processes and their related upstream processes. The systemic GWP for DMLS is 69 kg CO2 equivalent, while for FDM it is 89 kg CO2 equivalent, per kilogram of material processed. Using the ReCiPe 2008 method, damage to human health is predicted to outweigh damage to ecosystem quality and resource availability for the DMLS process. For the FDM process, damage to human health and resource availability are predicted to outweigh damage to ecosystems quality. This work concludes that electrical energy use is the key contributor to systemic environmental impacts of additive manufacturing. Thus, it is imperative that we identify solutions to generate clean electrical energy, reduce electricity transmission losses, reduce material processing energy use, and design products that enable efficient additive manufacturing.

Flexible one-structure arched triboelectric nanogenerator based on common electrode for high efficiency energy harvesting and self-powered motion sensing

Triboelectric nanogenerators are widely used because of low cost, simple manufacturing process and high output performance. In this work, a flexible one-structure arched triboelectric nanogenerator (FOAT), based on common electrode to combine the single-electrode mode and contact-separation, was designed using silicone rubber, epoxy resin and flexible electrode. The peak-to-peak short circuit current of 18μA and the peak-to-peak open circuit voltage of 570V can be obtained from the FOAT with the size of 5×7 cm2 under the frequency of 3Hz and the pressure of 300N. The peak-to-peak short circuit current of FOAT is increased by 29% and 80%, and the peak-to-peak open circuit voltage is increased by 33% and 54% compared with single-electrode mode and contact-separation mode, respectively. FOAT realizes the combination of two generation modes, which improves the output performance of triboelectric nanogenerator (TENG). 62 light-emitting-diodes (LEDs) can be completely lit up and 2.2μF capacitor can be easily charged to 1.2V in 9s. When the FOAT is placed at different parts of the human body, the human motion energy can be harvested and be the sensing signal for motion monitoring sensor. Based on the above characteristics, FOAT exhibits great potential in illumination, power supplies for wearable electronic devices and self-powered motion monitoring sensor via harvesting the energy of human motion.

Feature-based characterisation of signature topography in laser powder bed fusion of metals

The use of state-of-the-art areal topography measurement instrumentation allows for a high level of detail in the acquisition of topographic information at micrometric scales. The 3D geometric models of surface topography obtained from measured data create new opportunities for the investigation of manufacturing processes through characterisation of the surfaces of manufactured parts. Conventional methods for quantitative assessment of topography usually only involve the computation of texture parameters, summary indicators of topography-related characteristics that are computed over the investigated area. However, further useful information may be obtained through characterisation of signature topographic formations, as more direct indicators of manufacturing process behaviour and performance. In this work, laser powder bed fusion of metals is considered. An original algorithmic method is proposed to isolate relevant topographic formations and to quantify their dimensional and geometric properties, using areal topography data acquired by state-of-the-art areal topography measurement instrumentation.

Hue tunable, high color saturation and high-efficiency graphene/silicon heterojunction solar cells with MgF2/ZnS double anti-reflection layer

Graphene/silicon (Gr/Si) heterojunctions with simple manufacturing process, high stability and excellent device performance have great potential in photovoltaic (PV) applications. In comparison to conventional PV panels with monotone colors, multi-color PV panels could be integrated in modern building facades and thus largely expand their application ranges. In this work, multi-color Gr/Si heterojunction PV devices were fabricated, for the first time, by taking advantage of the combination of ultra-thin highly transparent graphene and MgF2/ZnS anti-reflection coating. The double-layer film coating enabled the multi-color Gr/Si PV devices with both high color saturation and low optical loss. The PV devices exhibited respectable power conversion efficiency (PCE) in the range of 10.7–13.2%, depending on the color of the devices. In addition, PCE of the device with optimized anti-reflection coating reached as high as 14.6%, which is among the highest for the Gr/Si heterojunction solar cells. By varying the film thickness at different positions, a colored Gr/Si solar cell with visible pattern was made on a 2-in. Si wafer. Our work demonstrates the great potential of multi-colored Gr/Si solar cells for new-generation distributed solar energy systems with designable features.

CBR600发动机排气优化设计

本论文以2016 FSAE中国大学生方程式汽车大赛为背景，设计并制造了一辆方程式赛车的排气系统。整个设计过程在满足大赛规则的基础上，实现了降低排气系统的重量、提高了排气效率和发动机的动力表现并且满足了制造工艺性能的要求。 Based on the 2016 FSAE formula student China, we design and manufacture a high performance exhaust system for a formula car. In the whole design process, the weight of exhaust system, the exhaust efficiency and the dynamic performance of the engine were realized on the basis of meeting the rules of the competition, and the requirements of the manufacturing process performance were satisfied.

Sustainable-value stream mapping to evaluate sustainability performance: case study in an Indonesian furniture company

Lean manufacturing tools do not consider environmental and societal benefits. The conventional value stream mapping (VSM) methodology examines the economics of a manufacturing line, most of which are in regards to time (cycle time, lead time, change-out time, etc.). Incorporating the capability to capture environmental and societal performance visually through VSMs will increase its usefulness as a tool that can be used to assess manufacturing operations from a sustainability perspective. A number of studies have addressed the extension of VSM to incorporate additional criteria. A vast majority of these efforts have focused on adding energy-related metrics to VSMs, while several other studies refer to ‘sustainable’ VSM by including environmental performance in conventional VSMs. This research has developed a method for VSM integrated with environment metric and social metric for ensuring sustainable manufacture. The proposed technique is capable of visualizing and evaluating manufacturing process performance from sustainability view point. The capability of proposed technique has been tested by an application study on furniture company. The study provides insights to practitioners to visualize process performance in economic, environment and social metric.

Evaluation of Manufacturing Process Performance by CONWIP Hybridization of Pull Controlled Production Systems

The main objective of this paper is pioneering an innovative tactic for the synchronization of multi-stage, multi-line, production system. This tactic is mainly depends on the optimization policy, by means of distinct event simulation process for modeling, analysis and distinction of the execution of two alternatives of Kanban control mechanism namely SEKCS (Simultaneous Extended Kanban Control System) and IEKCS (Independent Extended Kanban Control System). At this juncture the authors putting forward the two variants of Extended Kanban control system with the hybridization of CONWIP control policy to incite HSEKCS (Hybrid Simultaneous Extended Kanban Control System) and HIEKCS (Hybrid Independent Extended Kanban Control System) to make use of pooled benefits of a representative production situation in addition to improve the outcome. Therefore in this study the comparison in between different systems of proposed HEKCS specifically are HSEKCS and HIEKCS compared with the Extended Kanban Control Systems variants SEKCS and IEKCS. Simulation studies were conducted for all the five control policies considered and modeled on a multi-line, multi-stage assembly production control system. The relative performance parameters like Throughput or Production rate, Average Waiting Time and Average Work-in-Process, were assessed by means of exponentially varying demands.

Evaluation of Manufacturing Process Performance by CONWIP Hybridization of Pull Controlled Production Systems

The main objective of this paper is pioneering an innovative tactic for the synchronization of multi-stage, multi-line, production system. This tactic is mainly depends on the optimization policy, by means of distinct event simulation process for modeling, analysis and distinction of the execution of two alternatives of Kanban control mechanism namely SEKCS (Simultaneous Extended Kanban Control System) and IEKCS (Independent Extended Kanban Control System). At this juncture the authors putting forward the two variants of Extended Kanban control system with the hybridization of CONWIP control policy to incite HSEKCS (Hybrid Simultaneous Extended Kanban Control System) and HIEKCS (Hybrid Independent Extended Kanban Control System) to make use of pooled benefits of a representative production situation in addition to improve the outcome. Therefore in this study the comparison in between different systems of proposed HEKCS specifically are HSEKCS and HIEKCS compared with the Extended Kanban Control Systems variants SEKCS and IEKCS. Simulation studies were conducted for all the five control policies considered and modeled on a multi-line, multi-stage assembly production control system. The relative performance parameters like Throughput or Production rate, Average Waiting Time and Average Work-in-Process, were assessed by means of exponentially varying demands.

Tolerance analysis in manufacturing using process capability ratio with measurement uncertainty

Tolerance analysis provides valuable information regarding performance of manufacturing process. It allows determining the maximum possible variation of a quality feature in production. Previous researches have focused on application of tolerance analysis to the design of mechanical assemblies. In this paper, a new statistical analysis was applied to manufactured products to assess achieved tolerances when the process is known while using capability ratio and expanded uncertainty. The analysis has benefits for process planning, determining actual precision limits, process optimization, troubleshoot malfunctioning existing part. The capability measure is based on a number of measurements performed on part’s quality variable. Since the ratio relies on measurements, elimination of any possible error has notable negative impact on results. Therefore, measurement uncertainty was used in combination with process capability ratio to determine conformity and nonconformity to requirements for quality characteristic of a population of workpieces. A case study of sheared billets was described where proposed technique was implemented. The use of ratio was addressed to draw conclusions about non-conforming billet’s weight expressed in parts per million (ppm) associated with measurement uncertainty and tolerance limits. The results showed significant reduction of conformance zone due to the measurement uncertainty.

A review on benchmark artifacts for evaluating the geometrical performance of additive manufacturing processes

In recent years, additive manufacturing (AM) has undergone a rapid growth, therefore several processes based on different working principles (e.g. photopolymerization, sintering, extrusion, material jetting, etc) are now available and allow to manufacture parts using a wide range of materials. Consequently, the so-called benchmark artifacts are necessary to assess the capabilities and limitations of each AM process or to compare the performance of different processes. This paper focuses on the benchmark artifacts for evaluating the geometrical performance of AM processes and proposes an extensive review of the available literature, analyzing the design of such test parts in detail. The investigated test parts are classified according to the process aspect that they are able to evaluate (dimensional/geometrical accuracy, repeatability, minimum feature size) and the combination AM process/materials for which they have been used. In addition, the paper draws a summary of guidelines to design benchmark artifacts for geometrical performance evaluation.

Conversion Economics of Forest Biomaterials: Risk and Financial Analysis of CNC Manufacturing

AbstractCommercialization of cellulose nanocrystals (CNC) presents opportunities for a wide range of new products. Techno‐economic assessments can provide insightful information for the efficient design of conversion processes, drive cost‐saving efforts, and reduce financial risks. In this study, we conducted techno‐economic assessments for CNC production using information from the USDA Forest Products Laboratory Pilot Plant, literature, and discussions with experts. Scenarios considered included variations related to greenfield, co‐location, and acid recovery. Operating costs, capital investment, minimum product selling price (MPSP), financial performance metrics, and the effect of drying and higher reaction yields on CNC manufacturing financials were estimated for each scenario. The lowest MPSP was found for the co‐location without acid recovery scenario, mainly driven by capital investment. Risk analysis indicates 95% probability of manufacturing costs lower than USD 5900/t of CNC (dry equivalent) and a MPSP lower than USD 7200/t of CNC (dry equivalent). Finally, based on our analysis, we provide guidance on process optimizations that can improve the economic performance of CNC manufacturing process. In addition, a risk profile of the CNC manufacturing business is provided. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd

A Review on Optimization of Manufacturing Process Performance

A Review on Optimization of Manufacturing Process Performance

Finish turning of Ti-6Al-4V with the atomization-based cutting fluid (ACF) spray system

Product quality and productivity are important factors in manufacturing industries, especially when dealing with cumbersome materials like titanium. Cooling and lubrication effects offered by the associated metalworking fluid application system play a vital role in determining these factors, especially during finish cutting. Recently, the atomization–based cutting fluid (ACF) spray system has shown promising cooling and lubrication effects during rough turning of titanium at the macro–scale, but yet to be examined during finish cutting (e.g., depth of cut and feed rate 0.2mm or lower). This paper aims to study the effect of the ACF spray system on machining performance during finish turning of Ti-6Al-4V. In the first set of experiments, two spray parameters (viz., gas velocity and flow rate) and cutting parameters (viz., cutting speed, feed rate and depth of cut) are varied to select the most suitable condition for the application of the ACF spray system. Machining outputs are evaluated in terms of nose wear, cutting temperature, surface roughness, roundness error, chip morphology, and part hardness. A separate set of experiments is then performed to compare the performance of the ACF spray system against compressed air (dry) and flood coolant conditions. It is found that, even a lower fluid flow rate of 1.5mL/min (10vol.%) at a lower gas velocity of the spray system outperforms the other two coolant conditions, thus further enhancing the performance of environmentally-friendly manufacturing process.

Monitoring multivariate Poisson processes: a review and some new results

Evaluation of performance and quality of manufacturing and business processes using statistics is a central issue. Process quality depends on several characteristics that should be assessed using simultaneous multivariate quality control methods. Multivariate variable process control has been one of the most rapidly developing areas of statistics. The paper is focused on monitoring quality characteristics of the attribute type and following non normal distributions. In particular, the multivariate Poisson process is considered. The main theoretical results on monitoring multivariate attribute processes and the multivariate Poisson process are reviewed and discussed. Little work has been carried out on statistical methods to monitor multivariate attribute processes and many problems in developing multi-attribute monitoring methods are still open. In the paper, we propose a new index of the overall defectiveness and a two-sided Shewhart-type multivariate control chart with asymptotic probabilistic limits for monitoring the defectiveness or demerit degree. The proposed methods provide a solution to the identification problem.