Low-volume Production Research Articles

Data driven automatic parameter inference for robotic assembly programs

In a high-mix low volume production environment, time to market is a key factor. However, one bottleneck lies in the often times manual parametrization of machines for new or modified designs. A truly flexible manufacturing environment therefore requires a continuous data flow from the design stages to the shop floor. This paper presents a concept for the automated parameterization of machines at a large automotive plant. It describes the interface requirements of the stakeholders involved as well as the overall system architecture. Finally, the paper presents first results of a prototype tested in serial production, spanning more than 100 machines.

Generative design case study of a CNC machined nose landing gear for an unmanned aerial vehicle

Generative design is a design method inspired by nature’s evolution, pushing the limits of the industry to new design solutions. Using minimum input requirements, the resulting designs can be structurally adequate, weight-optimised and almost production-ready. The main purpose of this paper is to present the different approaches of the standard engineering design and the generative design methods. This is achieved through the case study of a nose landing gear for a prototype tactical unmanned aerial vehicle, intended for low volume production. The first part of the paper outlines the conceptual design of the nose landing gear. Subsequently, during the preliminary phase, the stress distribution along the different parts is calculated, based on the classic Strength of Materials theory and therefore a design solution is produced. In the second part, a generative design study is carried out with a commercially available tool, based on the conceptual parameters previously chosen. Both concepts are studied with industry-standard finite element analysis tools in order to validate, from a theoretical standpoint, the strength requirements according to the STANAG 4671 regulation. The final structure will be manufactured with 3-axis CNC machining, while providing about 36% weight reduction without compromising the structural functionality.

A Smart Manufacturing Cell with Distributed Intelligence

This paper presents a novel approach to implementing a smart manufacturing cell with distributed intelligence in the context of Industry 4.0. The system uses holons to model digital twins for a manufacturing cell and a Graph Node Network for production routing. The Graph Node Network allows dynamic generation of production routes for different parts. For prototyping, Robotic Operating System (ROS 2) is used, which provides a convenient way of representing individual digital twins (in the form of "nodes") for different equipment in the system. It also enabled us to create a decentralised and distributed architecture. The nodes are connected via Data Distribution Service, which utilises a publish/subscribe method for communications. The paper demonstrated a flexible, extensible, and fault-tolerant manufacturing cell that is geared toward a high-mix and low-volume production scenario.

The Effect of Printing Parameters on Crack Growth Rate of FDM ABS Cantilever Beam under Thermo-mechanical Loads

Fused deposition modelling (FDM) is the most widely used additive manufacturing (AM) process in the customised and low-volume production industries. Acrylonitrile butadiene styrene (ABS) is the most commonly used thermoplastic printing material for FDM. The fabricated FDM ABS parts commonly work under thermo-mechanical loads in reality. In order to produce the high fatigue performance FDM ABS components, it is significant to investigate the effect of 3D printing parameters on crack growth. Hence, this research evaluated the crack propagation under bending fatigue test for FDM ABS beam in high-temperature conditions with varying printing parameters, including building orientations, nozzle size and layer thickness. The combination of three building orientations (0°, ±45° and 90°), three nozzle sizes (0.4, 0.6 and 0.8 mm) and three layer thickness (0.05, 0.1 and 0.15 mm) were tested under 50 to 70 °C environmental temperature ranges. The research attempted to investigate the relationship between crack growth rate and different printing parameter combinations. The study also attempted to determine the possible parameter combination which achieved the longest fatigue life for the FDM ABS specimen. Preliminary experimental results showed that the specimen with 0° building orientation, 0.8 mm filament width and 0.15 mm layer thickness vibrated for the longest time before the fracture at every different temperature.

Acquisition of expert’s knowledge for high-mix and low-volume production scheduling problem

Acquisition of expert’s knowledge for high-mix and low-volume production scheduling problem

Cost Modeling and Evaluation of Direct Metal Laser Sintering with Integrated Dynamic Process Planning

Additive manufacturing technologies have been adopted in a wide range of industries such as automotive, aerospace, and consumer products. Currently, additive manufacturing is mainly used for small-scale, low volume productions due to its limitations such as high unit cost. To enhance the scalability of additive manufacturing, it is critical to evaluate and preferably reduce the cost of adopting additive manufacturing for production. The current literature on additive manufacturing cost mainly adopts empirical approaches and does not sufficiently explore the cost-saving potentials enabled by leveraging different process planning algorithms. In this article, a mathematical cost model is established to quantify the different cost components in the direct metal laser sintering process, and it is applicable for evaluating the cost performance when adopting dynamic process planning with different layer-wise process parameters. The case study results indicate that 12.73% of the total production cost could be potentially reduced when applying the proposed dynamic process planning algorithm based on the complexity level of geometries. In addition, the sensitivity analysis results suggest that the raw material price and the overhead cost are the two key cost drivers in the current additive manufacturing market.

Craft beer: An overview.

The purpose of the work was to provide an overview on craft beer. Details and issues concerning history and legal definition market, fiscal policy, innovation, safety, healthiness, consumer profile, and sustainability are supplied. The term "craft brewery" generally refers to a brewery able to produce low volumes of beer, often made with traditional ingredients-for emulating historic styles-but also with the addition of nontraditional ingredients as a distinctiveness sign of the master brewer. In many countries, the importance of the company size is related to the opportunity to take advantage of reduced excise rates for low production volumes. In several countries, another important requisite of a craft brewery is represented by its independence from other alcohol industry members. Even in the presence of a great heterogeneity of the size of craft breweries in the various countries, their number in the world is around 17,000. Craft beer is mainly consumed in restaurants and bars. Innovation of craft beer concerns aspects, such as ingredients, alcohol content, aging, and packaging, and the profile of the typical craft beer drinker is that of a young man, with a higher education and a medium-high income. Craft beers are often not filtered/not pasteurized and, for these reasons, they are beverages rich in health compounds but with a reduced shelf life. As in the case of larger breweries, the environmental impact of craft breweries is mainly represented by water consumption and production of liquid and solid wastes.

Preliminary Techno-Economic Assessment of Animal Cell-Based Meat.

Interest in animal cell-based meat (ACBM) or laboratory-grown meat has been increasing; however, the economic viability of these potential products has not been thoroughly vetted. Recent studies suggest monoclonal antibody production technology can be adapted for the industrialization of ACBM production. This study provides a scenario-based assessment of the projected cost per kilogram of ACBM produced in the United States based on cellular metabolic requirements and process/chemical engineering conventions. A sensitivity analysis of the model identified the nine most influential cost factors for ACBM production out of 67 initial parameters. The results indicate that technological performance will need to approach technical limits for ACBM to achieve profitably as a commodity. However, the model also suggests that low-volume high-value specialty products could be viable based on current technology.

Comparative Study of Incremental Forming and Elevated Temperature Incremental Forming Through Experimental Investigations on AA 1050 Sheet

Abstract Unlike conventional forming processes, incremental forming (IF) does not require any part-specific tooling. It is a flexible forming process that is suitable to form user-specific shapes and for low volume production. The IF process has been recognized as a promising manufacturing process over conventional forming for the materials having decent formability. However, it does not give reliable results while forming hard to form materials. A few investigations revealed that heat plays a vital role in enhancing the formability. On heating, the yield stress of the materials gets reduced, the ductility increases, and hence the formability improves. Thus, for the materials having poor formability, an advance IF technique, elevated temperature incremental forming (ET-IF), has been developed. ET-IF involves incremental forming of the sheets while being heated by an external heat supply. This research study focuses on the execution of the ET-IF process and its comparison with the conventional IF process. A radiation type heating device to perform the ET-IF process is designed and fabricated. The experimental investigations were carried out on 1 mm thick AA 1050 sheets by carrying out the IF process at room temperature and enhanced temperatures. Experimentation was initiated with performing straight grove tests, which were later extended to form a few more shapes. Experimental results confirm the delay in fracture and intensification of formability with the ET-IF process in comparison to that of the IF process at room temperature. The work overcomes the limitation and enlarges the scope of application of the IF process.

Economics of production and marketing of apple (Malus domestica) in Mustang, Nepal

A study was carried out to assess the production and marketing status of apple in the Mustang district of Nepal in 2019. A total of 100 households were sampled by using simple random sampling technique and interviewed with a pre-tested semi-structured questionnaire. Descriptive statistics and independent-sample t-test was used for data analysis using SPSS and MS-Excel. Farmers were categorized into small farmers (n=68) and large farmers (n=32) based on the number of apple trees grown by farmers. The average area under apple cultivation was 6.64 ropani (0.3378 hactares). The overall average apple production was 2848 kg (2.84 Mt) and the large farmers had more apple production (7035 kg) as compared to small farmers (877 kg). The average annual household income from apple was NRs. 29,868 (248.90 USD). Apple farming was found to be a profitable farm enterprise with a benefit-cost ratio of 1.84. Two marketing channel was identified in the study area and Channel II was found more profitable. Education status of household head, ethnicity, number of economically active family members, experience on apple farming and visit of extension worker to apple farms were the significant factors that positively affected the production and marketing of apple. The satisfaction level of farmers from production and marketing of apple was found very poor (79%). Unavailability of inputs, lack of storage facilities, insect pest damage, poor technical knowledge and infrastructure were major production problems. Similarly, price variation, poor marketing infrastructure and linkage, high postharvest loss, poor bargaining power and low volume of production were the major marketing problems.

Assessment of Additive Manufacturing for Increasing Sustainability and Productivity of Smallholder Agriculture.

The System of Rice Intensification (SRI) seeks to increase both the sustainability and the productivity of smallholder rice farms, but the adoption of this methodology is constrained by local access to appropriate mechanical equipment. Valuable information about real difficulties in the adoption of SRI was collected through communications with five field partners. Two primary mechanization obstacles were identified, that is, the availability and performance of a roller component on a push seeder and a rotor component on a push weeder. The potential of additive manufacturing (AM), and especially material extrusion three-dimensional (3D) printing (ME3DP), to assist in overcoming the identified obstacles was assessed for two cases while considering both local prototyping and low-volume production. A simplified cost model was used to compare with the cost of manufacturing both in the United States and locally in the field. The acquired data suggests that in specific cases current ME3DP technology can more rapidly provide functional parts, accelerating the design cycle and lowering cost by about a factor of 10 relative to local fabrication routes. In the case where mechanical performance is critical and dimensional precision and surface finish are not, wire arc metal AM appears promising, but it is not as economical as fabrication by traditional means in the field.

There’s plenty of room at the top

Abstract Richard Feynman’s famous words, “there’s plenty of room at the bottom,” referred to the opportunities for revolutionizing the electronics industry by developing the science and technology of how to manufacture very small components (sub-micron to nanometer sized features) (Feynman, 1959) [ 1 ]. In additive manufacturing (AM), the opposite may be true: There’s plenty of room at the top. AM’s strength is in the low volume production of complex components, which is demanded in big industries such as oil and gas, construction, tooling, wind and water turbines, and infrastructure. Is AM’s ‘big’ future in the manufacture of large structures? This special issue surveys the technical challenges and enormous opportunities associated with large scale additive manufacturing while discussing the materials, processes and applications that are enabled by scaling to much larger structures, much faster speeds and lower manufacturing costs. The authors believe that, if Professor Feynman was alive, he’d say “There’s plenty of room at the top.”

Scalable Processing Routes for the Production of All‐Solid‐State Batteries—Modeling Interdependencies of Product and Process

The all‐solid‐state battery (ASSB) based on a solid ionic conductor is a significant future concept for energy storage. In respect of the growing global demand for batteries, a systematic study on processing thin‐layer and large‐area ASSBs is addressed herein. As ASSB cells are mainly produced on a laboratory scale, an introduction to industrial production is needed. Therefore, the formation, ranking, and selection of technology chains are presented concerning the strategic orientation of cell manufacturing companies. A system model consisting of five sub‐models is created, which connects technologies with production‐relevant parameters. The results are used for a tool that automatically generates and evaluates technology chains in dependence of the ASSB cell design. Starting from the layer fabrication technologies further up‐ and downstream processes are defined. For sulfidic solid electrolytes, e.g., a ball milling followed by the aerosol deposition method, hot pressing, and laser cutting are favorable in terms of high‐quality layers and low production volume, whereas planetary mixing, tape casting, calendering, and die cutting are the choice for a high‐throughput production. Based on these findings, processing routes for every cell design and solid electrolyte material can be generated concerning company‐specific criteria, thus enabling the industrial application.

Barriers to the Development of Organic Farming: A Polish Case Study

The main purpose of this paper is to explore farmers’ opinions on the barriers to the development of organic farming. A survey was carried out with 262 Polish organic farmers in order to classify the barriers to organic farming development into production, and economic aspects, market aspects and institutional and regulatory aspects. As a next step, a detailed analysis was performed of how the farmers view these barriers. According to this study, Polish organic farmers attach greater importance to economic factors than to non-economic ones. Low yields and production volumes are the reason why many farmers see organic farming as being risky. More than 80% and nearly 60% of farmers covered by this study found the production risk to be very high or high, respectively, during and after the conversion period. Most farmers say they intend to continue their organic production activity only if financial support is provided. Nearly one in five farms (18.3%) want to discontinue organic production in future. This is especially true for two types of farming: specialized grazing livestock farms and mixed holdings. The farmers believe that market aspects and institutional and regulatory factors are the key barriers to the development of organic farming. The findings regarding the role of institutional barriers and communications from regulatory institutions, which affect the farmers’ decision-making processes, are of particular importance. In Poland, the main institutional problem is the instability of laws applicable to organic farming, which adds to the farmers’ uncertainty and decision-making risks. The case study of Poland, which is among the emerging markets for organic food, shows that a stable and coherent support policy is a condition for organic-farming development.

Effective Maintenance by Reducing Failure-Cause Misdiagnosis in Semiconductor Industry (SI)

Increasing demand diversity and volume in semiconductor industry (SI) have resulted in shorter product life cycles. This competitive environment, with high-mix low-volume production,requires sustainable production capacities that can be achieved by reducing unscheduled equipment breakdowns. The fault detection and classification (FDC) is a well-known approach, used in the SI, to improve and stabilize the production capacities. This approach models equipment as a single unit and uses sensors data to identify equipment failures against product and process drifts. Besides its successful deployment for years, recent increase in unscheduled equipment breakdown needs an improved methodology to ensure sustainable capacities. The analysis on equipment utilization, using data collected from a world reputed semiconductor manufacturer, shows that failure durations as well as number of repair actions in each failure have significantly increased. This is an evidence of misdiagnosis in the identification of failures and prediction of its likely causes. In this paper, we propose two lines of defense against unstable and reducing production capacities. First, equipment should be stopped only if it is suspected as a source for product and process drifts whereas second defense line focuses on more accurate identification of failures and detection of associated causes. The objective is to facilitate maintenance engineers for more accurate decisions about failures and repair actions, upon an equipment stoppage. In the proposed methodology, these two lines of defense are modeled as Bayesian network (BN) with unsupervised learning of structure using data collected from the variables (classified as symptoms) across production, process, equipment and maintenance databases. The proofs of concept demonstrate that contextual or statistical information other than FDC sensor signals, used as symptoms, provide reliable information (posterior probabilities) to find the source of product/process quality drifts, a.k.a. failure modes (FM), as well as potential failure and causes. The reliability and learning curves concludes that modeling equipment at module level than equipment offers 45% more accurate diagnosis. The said approach contributes in reducing not only the failure durations but also the number of repair actions that has resulted in recent increase in unstable production capacities and unscheduled equipment breakdowns.

Comparative economics of maize grain and seed production in Okhaldhunga, Nepal

Maize (Zea mays L.) cultivation is very popular in Nepal. Basically, in the rural hills of Nepal such as Okhaldhunga, it dominates any other crop production. This study was done to for a comparative assessment of economics, marketing, and to identify major problems of maize seed and grain production in hilly eastern district of Okhaldhunga during June of 2017. The data were obtained by the interview of 66 purposively selected producers (33 each of maize grain and seed producers) with the use of pre-tested semi-structured questionnaire. Both the grain and seed producers were similar in terms of socio-demographic characteristics and marketing accessibilities, but the seed producers were significantly benefited from the trainings, extension services, and credit facilities despite having comparatively small size of land holding (0.14 ha) than the grain producers. The inputs (manures, fertilizers, and the seed) contributed 48% and 50% of the total cost incurred for grain and seed production, respectively whereas the pre-sowing and sowing activities contributed more than 77% of cost in both the cases. In spite of higher cost for seed production, the benefit cost ratio of seed production was higher (1.52) than grain production (1.13). Findings also revealed that only 24% of the total harvest was processed and marketed as seed whereas using optimum quantity (66% middle portion of the cob) for seed production could further increase the income by 23.35%. The major production problems were scarce farm labor followed by lack of infrastructures, while low seasonal price followed by low volume of production ranked the first and second most important marketing related problems. Subsidies on the agri-inputs, timely availability of inputs, and encouragement of the youth towards agri-enterprise via various youth oriented programs can be done to overcome these problems.

Effect of channel dimension on biodiesel yield in millireactors produced by stereolithography

ABSTRACT Industrial research departments and chemical engineering institutes have begun to adopt additive manufacturing technologies, such as stereolithography for producing special types of reactors for continuous production. Microreactors have been widely used to improve the mass and heat transfer processes between immiscible liquid-liquid phases, but with the disadvantage of requiring sophisticated technology for their manufacture. In this paper, an approach for producing millireactors by stereolithography and rapid optimization of millireactor design with circular cross-section is presented. Transesterification of vegetable oils with alcohols is widely used method for biodiesel synthesis, generally taking place in a batch reactor. Microreactors due to their short residence times and high biodiesel yields are currently being explored for continuous production, but have disadvantages in low production volumes and high pressure drops. To overcome above-mentioned problems, millireactors with channel diameters from 1.5 mm to 3.5 mm were produced in order to investigate the impact of channel dimensions on conversion of sunflower oil to fatty acid methyl esters (FAME). Transesterification reaction of sunflower oil using methanol with addition of KOH base catalyst to FAME was monitored by Fourier-transform infrared spectroscopy, gas chromatography, and nuclear magnetic resonance. Results show that millireactors with smaller channel dimensions and processes with higher temperatures at certain residence times can be used to achieve better biodiesel yield in much shorter time than batch reactors. In addition, continuous way of FAME production in millireactors is presented. Production in millireactors provided an improvement when compared to microreactors because they have low pressure drops and higher production volumes.

Evaluation of the gas production enhancement effect of hydraulic fracturing on combining depressurization with thermal stimulation from challenging ocean hydrate reservoirs

The stimulation of hydraulic fracturing on a combination of depressurization with thermal stimulation for natural gas hydrate (NGH) exploitation from challenging ocean hydrate reservoirs is investigated in this study. The influence of fracture permeability, well spacing on hydrate exploitation, and the enhancement effect of hydraulic fracturing on different well spacing are numerically investigated. The results show that the hydraulic fracturing has a significant improvement on hydrate exploitation performance, including hydrate decomposition behaviour, gas production behaviour, gas recovery ratio, and energy ratio. This improvement enhances with the increase of fracture permeability, but the corresponding rate of increase gradually decreases. Gas production performance is extremely sensitive to well spacing. An extremely low gas production volume, gas recovery ratio and energy ratio will be obtained when well spacing is excessive. The existence of fracture can increase the effective well spacing. After fracturing, the gas production performance of each well spacing are significantly improved and this improvement performs better with larger well spacing.

Optimization of production cost for integrating job shop scheduling with production resources

New manufacturing technologies are emerging every day, pushing the bounds of possible and redefining the world around us. This is especially true in the world of computing where much work goes into the design and development of new planning systems, tools, and software packages. This led to the development of various process analysis and manufacturing software packages. Many of these packages use the heuristic methods for solving the problems. Optimization is a design technique in which the best design solution for a problem is seeded using multiple execution and comparison of analysis results. Optimization is carried out for one or more responses acted upon by various constraints. Job shop is an environment for the manufacture of large variety low volume products. In general, the integration of production functional areas with job shop scheduling problems is to be considered as too hard and complex problems. The Production functional areas are Material Requirement Planning, Production Resource Planning, Manufacturing Resource Planning, Employee Time tabling, Human Resource Planning and Lot Size etc. To minimize the loss due to resource allocation, integration of production function resources and job shop scheduling is encouraged. Production resources are resourcing the material, human labours and manufacturing machine tools. Manufacturing assumptions are deployed to found difficult integrated manufacturing systems. In this paper, a hierarchy mathematical modelling approach has been developed to integrate the production resources planning and job shop scheduling. In which, material requirement planning system for material resource arrangement, employee timetabling module for human resource allocation and manufacturing resource planning for machine allocations are to be considered. For solving the unique hierarchy model, a shuffled frog leaping heuristic algorithm (SFLA) is proposed and implemented for minimizing the overall production cost. To prove the optimized results, the integrated system has been tested with real time case studies.

Design and structural analysis of 3D-printed modular furniture joints

Modular furniture joint defined as a connection used to connect two or more wood pieces to produce furniture with multiple functions. Notofusy furniture joint made from plywood was less expensive. However, during the manufacturing process, it was occasionally caused tear-out of wood fibre. Therefore, this research has been carried out to investigate and compare the existing material and Fused Deposition Modelling (FDM) fabrication method on the designed modular furniture joint. Finite Element Analysis (FEA) of elasto-plastic method from ABAQUS CAE software and three-point bending test were used to evaluate the structural analysis of designed modular furniture joint. In this research, the final concept selected was able to withstand load up to 730 kg and it only weights 113.59 g. The long-term goal for this research was to evaluate the possibility of producing end products using FDM technology. It was found that FDM contributed to cost effective in low volume production. In this research, the material focused were Acrylonitrile Butadiene Styrene (ABS) and Polyethylene Terephthalate (PETG). However, future studies can be conducted to evaluate the possibility of using other 3D printing materials.