Flexibility-Driven Planning Of Flow-Based Mixed-Model Assembly Structures

Trends such as mass customization, changing customer preferences and resulting output fluctuations increasingly challenge the production industry. Mixed-model assembly lines are affected by the rising product variety, which ultimately leads to ascending cycle time spreads and efficiency losses. Matrix assembly addresses these challenges by decoupling workstations and dissolving cycle time constraints while maintaining the flow. Both matrix and line assembly are flow-based assembly structures characterized by assembly objects moving along the stations. In assembly system planning, competing assembly structures are developed and the one best meeting the use case's requirements is selected for realization. During assessing requirements and selecting the superior assembly structure, the systematic consideration of flexibility is often not ensured within the planning approach. Therefore, a preferred assembly structure may not have the flexibility required for a use case. The systematic and data-driven assessment of required and provided flexibility in assembly system planning is necessary. This paper presents an assessment model that matches a use case's requirements with the flexibility of flow-based assembly structures based on production program and process data. On the one hand, requirements are defined by flexibility criteria that evaluate representative product mixes and process time heterogeneity. On the other hand, provided flexibility of flow-based assembly structures is assessed in a level-based classification. A method for comparing the requirements and the classification's levels to prioritize assembly structures for application in a case is developed. The flexibility requirements and assembly structure of an exemplary use case are determined and discussed under the planning project's insights to evaluate the developed model. This work contributes to the objective and data-driven selection of assembly structures by utilizing use case-specific data available during the phase of structural planning to meet flexibility requirements and ensure their consideration along the assembly planning process

Defining flexibility of assembly workstations through the underlying dimensions and impacting drivers

The concept of mass customization is becoming increasingly important for manufacturers of assembled products. As a result, manufacturers face a high variety of products, small batch sizes and frequent changeovers. To cope with these challenges, an appropriate level of flexibility of the assembly system is required. A methodology for quantifying the flexibility level of assembly workstations could help to evaluate (and improve) this flexibility level at all times. That flexibility model could even be integrated into the standard workstation design process. Despite the general consensus among researchers that manufacturing flexibility is a multi-dimensional concept, there is still no consensus on its different dimensions. A Systematic Literature Review (SLR) shows that many similarities can be found in the multitude of flexibility dimensions. Through a series of interactive company workshops, we achieved to reduce them to a shortlist of 9 flexibility dimensions applicable to an assembly workstation. In addition, a first step was taken to construct a causal model of these flexibility dimensions and their determining factors, the so called drivers, through the Interpretive Structural Modelling (ISM) approach. In the next phase, a driver scoring mechanism will be initiated to achieve an overall assembly workstation flexibility assessment based on the scoring of drivers depending on the workstation design

Impacts of manufacturing flexibility on profitability: Malaysian perspective

As manufacturing flexibility has been purported as an unconventional manufacturing approach in safeguarding competitive advantage, this research was proposed to investigate the impact of manufacturing flexibility on profitability in the context of manufacturing industry in Malaysia.The dimensions of manufacturing flexibility were mix flexibility, new product flexibility, labor flexibility, machine flexibility, material handling flexibility, routing flexibility and volume flexibility.Impacts of manufacturing flexibility on profitability have been tested using cross sectional study employing survey methodology conducted within five manufacturing industries in Malaysia.Data obtained from returned questionnaires were analysed using regression analyses.Findings of regression analyses provided support that manufacturing flexibility has positive and significant impact on profitability. In other words, manufacturing flexibility improves profitability. In conclusion, this research contributes to knowledge gaining regarding the concept of manufacturing flexibility and its impacts

Metrics for identifying the most suitable strategy for distributed localised food manufacturing

The globalisation of manufacturing systems has generated many economic benefits, but in some areas such as the food sector, it has also increased resource requirements to manufacture, preserve and transport raw ingredients as well as finished products. ‘Distributed Localised Manufacturing’ (DLM) has been identified as a potential solution for the food sector to adopt a more sustainable approach based on a make-to-order manufacturing strategy. This has the potential to minimise food waste, optimise resource usage, and support product customisation. However, DLM performance analysis at product, process and system levels is vital to ensure its long-term ecological and economic viability. This paper highlights four possible models for implementation of DLM in the food sector, defines nine key metrics to aid with selection of the most suitable DLM model for a specific food product family, and explores metrics future applications to support long-term sustainability of food manufacturing

Assessment of Optimal Production Through Assembly Line-Balancing and Product-Mix Flexibility

Timely accomplishment of production targets is a challenging task in low volume–high variety environment. Assessment of the manufacturing flexibility of a production system assists in achieving the desired objectives. In this research, the operational flexibility of a production system is investigated which operates under the low-volume high-variety production scenario. Prospective dimensions of theproduction flexibility are studied to analyze its interface with the integrated functional units. It was analyzed that with a low-volumeoperational flexibility (OF) varies rationally despite high job varieties. Line-balancing and queuing techniques are applied to ascertain theoptimum productivity. A sensitivity analysis is also performed to evaluate the critical parameters that affect the OF and productivity level.OF index of the production system was estimated by means of the optimized production parameters. A comparative analysis is performedto evaluate the flexibility in conventional and flexible production cells. Analytical and computational results show a close approximationand validate the implemented schemes

Potentials and Implementation Strategies For Flexible Battery Cell Production

The effects of a fossil fuel-based economy are becoming increasingly apparent. The storage and use of renewable energy sources are a key strategy to reduce overall greenhouse gas emissions. In this context, the demand for batteries as a suitable medium for energy storage is increasing rapidly. Lithium-ion batteries pioneered in consumer electronics are nowadays used in ever more applications, with the e-mobility sector being one of the most prominent. From a production perspective, the process chain for manufacturing of such lithium-ion batteries can be divided into three main sections: electrode production, cell assembly and cell finishing. However, actual implementation of the process chain differs substantially, depending on the selected cell format (pouch, cylindric, prismatic) and design, manifesting in cell-specific processes (e.g. stacking vs. winding), supplementary and/or omitted process steps and manufacturing technologies (e.g. pouch foil heat sealing vs. hard case laser welding). Currently there is no strictly preferred cell format, as each format has its advantages and disadvantages, depending on its intended application and system integration. Production of different battery cell types thus is spread across various international mostly Asian manufacturers, most of which have large scale mass production lines dedicated to a single specific format. Only a few manufacturers have a portfolio of formats (e.g. round and prismatic) in large quantities. Against this background, the following paper provides an overview of the product variety of lithium-ion batteries available on the market, following up with a discussion of potentials and implementation strategies for flexible battery cell production. First, applications and business areas for lithium-ion batteries are analysed and general flexibility areas regarding the battery cell design are derived. Subsequently, the impacts of the different flexibility areas on the production processes are analysed. In a final step, different implementation strategies and approaches for increased flexibility in battery cell production are elaborated

Investigating Flexibility as a Performance Dimension of a Manufacturing Value Modeling Methodology (MVMM): A Framework for Identifying Flexibility Types in Manufacturing Systems☆

Abstract In recent years manufacturing companies have been faced with various challenges related to volatile demand and changing requirements from customer as well as suppliers. This trend is now even accelerating with a direct impact on the value chain. New technological roadmaps and suggested interventions in manufacturing systems try to solve these challenges and solutions such as the German high tech strategy "Industrie 4.0" or the Italian cluster "Fabbrica Intelligente" which often aimed at enhancing the flexibility of manufacturing systems among many other competitive dimensions. However, these approaches often do not provide a detailed definition of flexibility and its different manifestations. Therefore, the question rises if different types of flexibility, that have an impact on the complete manufacturing system, can be better identified with the existing Manufacturing Value Modeling Methodology (MVMM). This question becomes even more important when considering the potential that smart machines interacting with humans, such as cyber-physical systems (CPS), and the possibility to increase connectivity and data access through technologies, such as the internet of things (IoT), offer for increasing flexibility. Especially due to the various possibilities it becomes even more important to understand, which kind of flexibility is needed for a given problem. Implementing flexibility into the MVMM requires a 'catalog' that makes use of the MVMM framework presenting an overview of internal and external influence factors in order to support the identification of correct solutions and improvements related to functional areas in the manufacturing environment. Starting from a qualitative literature review on manufacturing flexibility, a 'flexibility catalog' is designed, which provides a structural definition of existing flexibility types and their composition as well as providing decision support. In conclusion, the scope of the 'flexibility catalog' is to verify that the flexibility demand fits into the market trends and is aligned to the manufacturing and company strategy, in order to help firms to take decisions and delivering value

Industry 4.0 enabling technologies for increasing operational flexibility in final assembly

The manufacturing industry is facing uncertainties caused by growing competition and increasing customer demands. Simultaneously, the fourth industrial revolution, commonly referred to as Industry 4.0, is helping in modernising the manufacturing industry. In the process of modernising, companies are now capable of building resilience into their systems. This resilience is in the form of higher operational flexibility, which helps cope with the growing uncertainties. The new technologies under the Industry 4.0 umbrella can be used to increase operational flexibility. This article summarises various Industry 4.0 enabling technologies that can increase operational flexibility in final assembl

Evaluation of Material Shortage Effect on Assembly Systems Considering Flexibility Levels

The global pandemic caused delays in global supply chains, and numerous manufacturing companies are experiencing a lack of materials and components. This material shortage affects assembly systems at various levels: process level (decreasing of the resource efficiency), system level (blocking or s tarvation of production entities), and company level (breaking the deadlines for the supplying of the products to customers or retailers). Flexible assembly systems allow dynamic reactions in such uncertain environments. However, online scheduling algorithms of current research are not considering reactions to material shortages. In the present research, we aim to evaluate the influence of material shortage on the assembly system performance. The paper presents a discrete event simulation of an assembly system. The system architecture, its behavior, the resources, their capacities, and product specific operations are included. The material shortage effect on the assembly system is compensated utilizing different system flexibility levels, characterized by operational and routing flexibility. An online control algorithm determines optimal production operation under material shortage uncertain conditions. With industrial data, different simulation scenarios evaluate the benefits of assembly systems with varying flexibility levels. Consideration of flexibility levels might facilitate exploration of the optimal flexibility level with the lowest production makespan that influence further supply chain, as makespan minimization cause reducing of delays for following supply chain entities