Design Of Assembly Systems Research Articles

Design and management of reconfigurable assembly lines in the automotive industry

Automotive suppliers are facing the challenge of continuously adapting their production targets to variable demand requirements due to the frequent introduction of new model variants, materials and assembly technologies. In this context, the profitable management of the product, process and system co-evolution is of paramount importance for the company competitiveness. In this paper, a methodology for the design and reconfiguration management of modular assembly systems is proposed. It addresses the selection of the technological modules, their integration in the assembly cell, and the reconfiguration policies to handle volume and lot size variability. The results are demonstrated in a real automotive case study.

Fixture Capability Optimisation for Early-stage Design of Assembly System with Compliant Parts Using Nested Polynomial Chaos Expansion

This paper introduces the novel concept of fixture capability measure to determine fixture layout for the best assembly process yield by optimizing position of locators and reference clamps to compensate stochastic product variations and part deformation. This allows reducing the risk of product failures caused by product and process variation. The method is based on three main steps: (i) physics-based modelling of parts and fixtures, (ii) stochastic polynomial chaos expansion to calculate fixture capability, and (iii) fixture capability optimisation using surrogate modelling. The methodology is demonstrated and validated using the results of an aerospace wing sub-assembly joined by riveting technique.

Method for Energy-efficient Assembly System Design within Physics-based Virtual Engineering in the Automotive Industry

Automated assembly systems in the automotive industry require thorough virtual validation procedures complementary to early design stages and prior to commissioning and ramp-up. This contribution introduces a conceptual method to assure an energy-efficient assembly system design within the virtual validation procedure Virtual Engineering as pre-process to Virtual Commissioning. As initial step of the method, relevant system planning data (sequence diagram, BOM, etc.) is analyzed in order to identify energy consumption units (ECUs) and their activities in the manufacturing process. Subsequently, physics-based simulation capabilities based on game engine technology are used to model individual ECUs (electric motors, pneumatic drives, robots, etc.) of the production system and the entire manufacturing process in a virtual 3D-CAE simulation environment. The simulation delivers energy signatures of both the entire production system on an aggregated level as well as on an individual ECU-level. Based on this data, energy efficiency improvement measures are implemented and validated in the virtual model of the assembly system. This entails an energy-efficient production system design while maintaining predefined production system settings like cycle-time and output. The conceptual method is exemplified by a use case of an automated assembly system from the automotive industry presenting preliminary results.

Application and Analysis of Modularity in Assembly Unit of Drying and Distribution Unit of Braking System of an Automobile

Modularity is a general concept, and many engineering problems can be generalized under the umbrella of modularity. Special structure of products poses challenges in the design of assembly systems which involves layout design, buffer design, line balancing, and transportation design and resource selection. An assembly line of Drying and Distribution Unit of an automobile has been selected for analysis and application of modularity. Assembly times at individual stations during different times of a day have been observed and analyzed. Modularity has been applied on the assembly line to minimize the total assembling time and idle time. It was found that the total number of components assembled has been increased by 7% after applying modularity. Flexsim simulation software has been used to simulate the assembly line, before and after applying the modularity and the results have been compared.

Assembly Modelling and Time estimating during the early phase of Assembly Systems Design

An approach for assembly time estimating following sequence and process modelling since the conceptual phase of new assembly systems design is proposed in this work. The purpose is to support the decision about their levels of automation (LoA) following a dedicated modelling language labeled ASML offering a better visibility about processes design and analyses. ASML provides an easy way of defining several systems alternatives based on an initial ASML model representing assembly motions using a standard vocabulary and structured executing architectures. The correlation of early phase modelling with time estimating proposed in this paper to support LoA decision is up to us new to the literature. The approach of modelling and time estimating was tested on assembly examples and a computerized tool was also developed and tested. Several related applications such as processes time performances evaluating, time savings, productivity assessment, lines balancing, and cost estimating are proposed as well as other possible future applications presented as perspectives and future works that can be supported by the defined environment dedicated to early phase assembly systems design and automation decision.

Competence Development for the Holistic Design of Collaborative Work Systems in the Logistics Learning Factory

Shorter product life cycles and emerging technologies in the field of industrial equipment are changing the prerequisites and circumstances under which the design of assembly and logistics systems takes place. Planners have to adapt the production in accordance with the underlying product at a higher pace, oversee a more complex system and – most importantly – find the ideal solution for functional as well as social interaction between humans and machines in a cyber-physical system. Such collaborative work systems consider the individual capabilities and potentials of humans and machines to combine them in a manner that assists the operator during his daily work routine towards more productive, less burdening work. To be able to design work systems which act on that maxim, specific competences such as the ability of integrated process and product planning as well as systems and interface competence are required. The ESB Logistics Learning Factory trains students as well as professionals to gain such qualification by providing a close-to-reality learning environment based on a didactical concept which covers all relevant methods for ergonomic work system design and a state-of-the-art infrastructure composed of an manual assembly system, service robots, visual assistance systems, sensor-based work load monitoring and logistical resources. Group-based, activity oriented scenarios enable the participants to put the learnings into practice within their professional environments. By this, Learning Factories have an indirect impact on the transfer of proven best practices to the industry and thereby on the diffusion of the idea of a human-centric working environment.

Systematic Design of SME Manufacturing and Assembly Systems Based on Axiomatic Design

To produce a high-quality product at the lowest possible price as quickly as possible, is certainly one of the biggest challenges of a manufacturing organization. In addition, supplier constraints and changes in the law for example makes it necessary for these enterprises to adapt continuously their manufacturing and assembly operations. The customization of products is increasing, and at same time, concepts of series and mass production are declining. This motivate large enterprises but also small and medium-sized enterprises (SMEs) to apply concepts of flexible and agile manufacturing and assembly systems to remain competitive and to react quickly to market changes and consumers’ preferences. The aim of this research is to develop a systematically design approach for such systems focusing on SME requirements which were carried out by a questionnaire survey of a sample of several manufacturing SMEs in Italy. Based on the survey results, Customer Attributes (CAs) are identified and then translated in Functional Requirements (FRs). Subsequently these FRs will be deduced into generally applicable Design Parameters (DPs) for supporting the design of flexible and changeable manufacturing and assembly systems for SMEs and to apply finally these design guidelines in a case study.

혼류생산 방식을 적용한 신개념 용접조립 기술 연구

Mixed-model production lines are often used in manufacturing systems. In production lines, different product types are simultaneously manufactured by processing small batches. This paper describes a new welding assembly technology involving the development of experimental models for a mixed-model production line in an automobile company. Due to the extensive number of models, the design of a welding assembly system is complicated. Performance evaluation is an important phase in the design of welding assembly lines in a mixed-model production environment. In this study, a new welding assembly technology for a mixed-model production method was used to weld the package tray and dash panel of a vehicle.

Axiomatic Design of a Reconfigurable Assembly System for Primary Wing Structures

Axiomatic Design of a Reconfigurable Assembly System for Primary Wing Structures

Integrated Product and Process Model for Production System Design and Quality Assurance for EV Battery Cells

The megatrend electric mobility induces a significant demand for high energy and high power secondary batteries. Currently lithium-ion technologies are the most promising solution for electrochemical energy storage in hybrid electric vehicles (HEV) and battery electric vehicles (BEV) [1; .Core factors that influence the quality, the performance and the cost of high energy lithium-ion batteries are production technologies, quality measurement techniques and quality management methods [3; . For this reason the Institute for Machine Tools and Industrial Management set up the Research Center for the Production of High-Energy Battery Cells (R-PHEB). In this research center production technologies are investigated according to industrial requirements. Research thrust areas are: first, process and assembly system design; second, quality assurance and management; and third, value chain analysis and design.The mass production of large lithium-ion cells for EV applications is an infant industry; new production technologies are often used in this field [. Hence, the influences of those processes on product properties are not known and the product quality can be evaluated only after the final production step. In order to obtain a resource efficient and economic production of lithium-ion cells, the correlations between the cell performance, the cell quality, the production processes and the assembly system design need to be revealed.This paper focuses on fundamental investigations of the process chain for the production of lithium-ion cells. It introduces a product-and a process-model, both of which specifically match the requirements in the field of battery production. The models can be used individually to describe the product structure or the process chain. Additionally they can be linked via a correlation matrix in order to visualize the dependencies between the requirement specifications of lithium-ion cells and the manufacturing processes (including process alternatives). Both models are based on a layered structure and contain information about battery cell design, battery type and production processes covering all tasks from coating the electrode coils to the start-of-operation of the cells.The product-model, the process-model and the correlation matrix will be implemented in a database, which in the future can be used for the methodical design of assembly systems as well as to investigate the correlations between process parameters and output quality. Furthermore, the database can assist when evaluating established process chains or preparing make-or-buy decisions in the context of battery cell production.

A mathematical programming approach for walking-worker assembly systems

Purpose – It has become increasingly critical to design and maintain flexible and rapid assembly systems due to unpredictable and varying market conditions. The first stage of developing such systems is to restructure the existing assembly system. After designing the manufacturing system, efforts should be made for capacity adjustments to meet the demand in terms of allocating tasks to workers. Walking-worker assembly systems can be regarded as an effective method to achieve flexibility and agility via rabbit chase (RC) approach in which workers follow each other around the assembly cell or line and perform each task in sequence. In this paper, a novel mathematical programming approach is developed with the aim of integrating RC in assembly processes. Therefore, this study is thought to add value to industrial assembly systems in terms of effectively raising engineering control for task allocation activities. Design/methodology/approach – Two consecutive mathematical models are developed, since such a hierarchical approach provides computational convenience for the problem. The initial mathematical programming model determines the number of workers in each RC loop for each segment. In addition, the number of stations and the distribution of station times in the segments is essential. Therefore, the succeeding mathematical programming model generates stations in each segment and provides convenience for the workflow in RC loops. The output of mathematical programming models are the parameters of simulation model for performance assessment. Findings – The effectiveness of the proposed approach was validated by an application in a real-life chair production system. The application resulted in performance improvements for labour requirement (12.5 per cent) and production lead time (9.6 per cent) when compared to a classical assembly system design (CASD) where one stationary worker exists in each station. In addition, it is worth to note that RC leads to a reduced number of workers for a considerable number (39.4 per cent) of test problems. What is more, input as well as output factors have been determined via discriminant analysis and their impacts to the utilization of RC were analyzed for different levels. Practical implications – This study is thought to add value to the industry in terms of effectively providing convenience during production planning and task allocation in assembly lines and cells. Originality/value – To the best knowledge of the author, optimization models for RC considering a real industrial application have not yet been developed. In this context, this paper presents an approach which models RC by the use of mathematical programming in manual assembly processes to address this research gap. The contribution of the paper to the relevant literature is the development of hierarchical mixed integer linear programming models to solve RC problem for the first time.

Design and simulation of assembly systems with mobile robots

This paper proposes an approach to the design and operation of assembly systems that include mobile robots. It is based on a semantic model representing the robot/resource skills along with the operations that a resource has to execute. The method is implemented in a system capable of generating the assignment of operations to the proper robotic resources. Collision free paths can be generated for the assembly system robots with the help of simulation. The method is presented in a case study from the automotive industry.

Integrated quality and production logistics modelling for the design of selective and adaptive assembly systems

Due to the increasing pressure on high precision manufacturing and the development of on-line measurement technologies, selective and adaptive assembly systems have attracted increasing interest in emerging sectors such as micro-production, biomedical and e-mobility industry. Selective assembly allows producing high precision assemblies from low precision components, at the cost of increasing the complexity of the system. This paper presents an integrated quality and production logistics model to profitably manage this trade-off. Results show that improved performance is achieved towards existing solutions, which deal only with quality aspects. The industrial benefits are shown through application to real manufacturing contexts.

The Methods for Increasing of the Efficiency in the Intelligent Assembly Cell

Efficiency of industrial production lines is crucial as it results in an improved production and utilization of available resources. Industry companies are constantly looking for new ways to improve workplace efficiency. Manufacturing industry trends to employ more flexible assembly cells with changes in programs and configurations for robots, and to achieve a high manufacturing efficiency. The various problems inherent in current mechanized product assembly are outlined, and potential organizational, technological, and engineering measures aimed at increasing the efficiency of product assembly are examined. Future developments in automated assembly are predicted. In order to improve the effectiveness of the cell, it is important to recognize measure and reduce losses in the assembly cell. The most effective method is to analyze the OEE (Overall Equipment Effectiveness) of the cell. It is developed design of assembly system under the project an intelligent assembly cell at the Institute of Production Systems and Applied Mechanics where after process running and debugging, based on the process analysis was evaluated, it is necessary to increase the efficiency of the cell. Deployment of monitoring, visualization and simulation are predicted defects that reduce overall system effectiveness. The project is aiming to develop an efficient intelligent manufacturing system integrating real time data collection, simulation, optimization and synthesis.

Algebraic expression of system configurations and performance metrics for mixed-model assembly systems

One of the challenges in the design and operation of a mixed model assembly system (MMAS) is the high complexity of the station layout configuration due to the various tasks that have to be performed to produce different product variants. It is therefore desirable to have an effective way of representing complex system configurations and analyzing system performances. By overcoming the drawbacks of two widely used representation methods (block diagrams and adjacency matrix), this article proposes to use algebraic expressions to represent the configuration of an MMAS. By further extending the algebraic configuration operators, algebraic performance operators are defined for the first time to allow systematic evaluation of system performance metrics, such as quality conforming rates for individual product types at each station and process capability for handling complexity induced by product variants. Therefore, the benefits of using the proposed algebraic representation are not only their effectiveness in achieving a compact storage of system configurations but also its ability to systematically implement computational algorithms for automatically evaluating various system performance metrics. Examples are given in the article to illustrate how the proposed algebraic representation can be effectively used in assisting the design and performance analysis of an MMAS.

Design of Assembly Systems for Large-Scale Battery Cells

The social and technical trends regarding electro mobility and the turnaround in energy policy cause an increasing demand on large-scale and high-quality lithium-ion cells as core components for electrical storage systems. Within the production of lithium-ion cells, cell assembly has to deal with diverse challenges which result from product complexity and a lack of production experience. This paper covers the design of assembly systems for large-scale lithium-ion cells and presents the enhancement of conventional design processes by three add-on modules. The first one is an analysis of product structure and design focus points and is described in this paper. The modules two and three are outlined.

Augmented reality aided interactive manual assembly design

Augmented reality (AR) is a novel technology which overlays computer-generated information seamlessly on the real-world environment. AR technologies have opened up a powerful set of tools for computer-aided assembly planning. This paper presents a manual assembly design system using AR technologies. An assembly data structure is devised for assembly information management. Algorithms for assembly constraint recognition and assembly location refinement have also been proposed. A hybrid approach based on these methods has been formulated and implemented to allow the users to simulate a manual assembly without the need for auxiliary computer-aided design information in assembly design. This would result in enhanced user experience and reduced preparation time. A methodology for 3D bare-hand interaction is integrated with this interactive manual assembly design system for the users to manipulate the virtual components in a natural and effective manner. A prototype system for interactive manual assembly design has been developed. An example has been provided to demonstrate the developed prototype system.

Prediction and analysis impact of operational design of a manual assembly system with walking workers on performance

Manual assembly lines, with workers travelling with the work along the line to perform all required tasks, are an example of assembly systems which have greater flexibility over traditional systems due to an improved response to product demand variability. Implementing assembly systems in this way is difficult, especially when operational design reflects an incomplete understanding of how workers can best perform within the system. Different operational designs for such systems have a profound impact on the performance of the system in terms of productivity and ergonomics. This paper analyses the performance of walking worker assembly line (WWAL) in different operational designs. A mathematical model was developed, which considers the effects of a number of operational design variables. An industrial case study is presented here to demonstrate the effectiveness of the proposed model. The results indicate that WWAL can be designed to improve performance, flexibility and labour costs by approaching productivity and ergonomics collaboratively. The results obtained by the model prediction were compared with computer simulation results. Comparison validated the accuracy of the proposed model. The model provides partial characterisations of the optimal design of WWAL and can be used to develop heuristics for local or global optimisation.

Design of a scalable assembly system for product variety: a case study

Purpose – The purpose of this paper is to develop and test a design approach based on the investigation of the sensitivity of assembly systems to volume fluctuations as part of the selection process of alternative design solutions for scalable assembly systems on the basis of a real industrial case study.Design/methodology/approach – A conceptual approach for the (re‐)design of a scalable assembly system is developed on the basis of an industrial case research using axiomatic design (AD) for the top level structuring of the framework incorporating useful methods and insights obtained from a thorough literature review and from previous research work.Findings – The findings of this research are limited due to the focused nature of a case study based research. However, the obtained results encourage assuming its transferability to similar problems.Originality/value – Significant research has been done in the design of assembly systems for high product variety, but the review of literature in this field still...

Concurrent Design of Product Families and Reconfigurable Assembly Systems

To cope with the challenges of market competition and the greater purchasing power of consumers, manufacturers have increased the variety of products they offer. Product families and reconfigurable manufacturing systems (RMS) are used to produce product variety cost-effectively. However, there is a lack of concurrent engineering methods for the joint design of a product family and an RMS, since existing concurrent engineering methods were developed for a single product and its associated manufacturing system. The presence of product variety brings challenges to the concurrent engineering of a product family and its reconfigurable assembly system (RAS), as the decision space is broader. This paper introduces a mathematical model for the concurrent design of a product family and a RAS. In addition, a mathematical model for the sequential approach to product family and RAS design is introduced to compare with the results of the concurrent methodology. A genetic algorithm has been developed to solve the models introduced for both the concurrent and sequential approaches. Examples are used to demonstrate the implementation of the concurrent approach to product family and RAS design and the benefits that could be achieved by using this approach. The solutions indicate that the concurrent design of product families and RASs leads to profits that are the same as or higher than the profits obtained with the sequential design approach. Therefore, the concurrent design of product families and RAS methodology is a more cost-effective approach to designing families of products and their associated manufacturing systems.