Assembly Process Planning Research Articles

Model-based assembly process planning for flexible aircraft cabin architectures

The configuration and equipment of an aircraft cabin has a significant impact on the passenger’s flight experience. To meet the needs of passengers and improve the flight experience, airlines repeatedly demand customised adaptations to the cabin design. The implementation of these changes requires a high degree of flexibility in production and can lead to difficulties in setting up a fixed final assembly line. In addition, unforeseen events and changes in the OEMs’ supply chain require a rapid response in aircraft production to be able to deliver on time. Digitalisation in product development and production planning makes it possible to overcome these challenges and makes an important contribution to flexibility, time and cost efficiency. This paper presents a digital approach to modelling and flexible planning of assembly processes of the cabin. To this end, aircraft design data is automatically linked to the assembly system to react quickly to design changes in the assembly planning process. The integration is realised in a system architecture model depicted with the systems modelling language (SysML). The architecture model follows the formal process description defined in VDI3682. A planning algorithm then uses the production architecture parameters to optimise the assembly processes, e.g. in terms of time. The approach presented is demonstrated using the example of scheduling the pre-assembly processes of the "crown module". The latter includes all structural and functional components above the window panels, such as overhead bins, electrics and air conditioning. The results show how changes in aircraft and cabin design or in the production plant and resources can be flexibly evaluated. This allows conceptual changes to be evaluated and traded before the cabin design is frozen and transferred to real production. These advantages contribute to the time and cost optimisation of aircraft production. This work thus makes a valuable contribution to the further development of digital solutions in aircraft production.

Automating the assembly planning process to enable design for assembly using reinforcement learning

AbstractThis paper introduces a new concept for the automation of the assembly planning process, to enable Design for Assembly (DfA). The approach involves the application of reinforcement learning (RL) to assembly sequence planning (ASP) based on a 3D-CAD model. The ASP algorithm determines assembly sequences through assembly by disassembly. The assembly sequence is then used for the generation of subassemblies by considering the product contact information. The approach aims to support the creation of the manufacturing bill of materials (MBOM) by automating the assembly planning process.

A knowledge-driven framework and methodology for precision assembly process decision making

Precision assembly process planning technology is one of the major challenges in the field of assembly. Compared with general assembly process planning, precision assembly process planning needs to consider a more complex assembly process, higher precision requirements, and more difficult process control. For this reason, it is of great significance to implement an intelligent assembly process planning and decision-making method for the development of precision assembly technology. This paper realizes the intelligent planning of precision assembly processes through the decision-making route of knowledge modeling and knowledge reasoning. Firstly, a theoretical system of a knowledge-driven precision assembly process decision-making framework is proposed. Secondly, a key precision assembly process decision-making technology is described in detail, which introduces a new approach for knowledge updates based on matching rules. Finally, the effectiveness of the knowledge update method is demonstrated through experimental cases. The knowledge-driven decision-making method combines the accuracy of domain experts’ empirical knowledge with the efficiency of intelligent reasoning algorithms. The knowledge update method ensures the currency of knowledge used for decision making. Therefore, the proposed precision assembly decision-making system framework and knowledge updating techniques in this paper are of great significance for knowledge-driven precision assembly process planning.

Assembly workshops in virtual reality as an integral part of the assembly planning process

Within the assembly planning process for automotive assembly lines, virtual reality (VR) systems are used mainly on a project-by-project basis. So far, there is no information about the knowledge gained from such workshops and the transferability of the results. Integration of VR as a standard process within the assembly planning has considerable potential. This paper addresses the question of how shopfloor employees and assembly planners can work efficiently in virtual environments on a solution for a concrete planning problem. Existing concepts for virtual workshops are analyzed and a multi-stage procedure for assembly workshops is derived. The assembly workshops in VR are used as a communication platform for different stakeholders, with a focus on the exchange with shopfloor employees. An implementation of the concept concerning its functionality is carried out based on a use case of the design of assembly tools for an automobile assembly line. For this purpose, an assembly platform for the accessibility of an assembly point inside the rear trunk of an automobile is designed in a joint VR workshop and transferred to an operational assembly line. The results show a broad acceptance of the developed solution among the employees.

Implementation of Digital Twin in Actual Production: Intelligent Assembly Paradigm for Large-Scale Industrial Equipment

The assembly process of large-scale and non-standard industrial equipment poses significant challenges due to its inherent scale-related complexity and proneness to errors, making it difficult to ensure process cost, production cycle, and assembly accuracy. In response to the limitations of traditional ineffective production models, this paper aims to explore and propose a digital twin (DT)-based technology paradigm for the intelligent assembly of large-scale and non-standard industrial equipment, focusing on both the equipment structure and assembly process levels. The paradigm incorporates key technologies that facilitate the integration of virtual and physical information, including the establishment and updating of DT models for assembly structures using actual data, the assessment of structural assemblability based on DT models, the planning and simulation of assembly processes, and the implementation of virtual commissioning technology tailored to the actual assembly process. The effectiveness of the proposed paradigm is demonstrated through a case study involving the actual assembly of a large-scale aerodynamic experimental equipment. The results confirm its ability to provide valuable technical support for the design, evaluation, and optimization of industrial equipment assembly processes. By leveraging the DT-based methodological system proposed in this paper, significant improvements in the transparency and intelligence of industrial equipment production processes can be achieved.

Design for mixed model final assembly line (DfMMFAL): a new tool for assembly interface identification based on assembly process planning

Purpose This paper aims to fulfil a need to identify assembly interfaces from existing products based on their Assembly Process Planning (APP). It proposes a tool to identify assembly interfaces responsible for reused components integration. It is integrated into a design for mixed model final assembly line approach by focusing on the identification of assembly interfaces as a generic tool. It aims to answer the problem of interfaces’ identification from the APP. Design/methodology/approach A tool is developed to identify assembly interfaces responsible for reused component integration. It is based on the use of a rule-based algorithm that analyses an APP and then submits the results to prohibition lists to check their relevance. The tool is then tested using a case study. Finally, the resulting list is subjected to a visual validation step to validate whether the identified interface is a real interface. Findings The results of this study are a tool named ICARRE which identify assembly interfaces using three steps. The tool has been validated by a case study from the helicopter industry. Research limitations/implications As some interfaces are not contained in the same assembly operations and therefore, may not have been identified by the rule-based algorithm. More research should be done by testing and improving the algorithm with other case studies. Practical implications The paper includes implications for new product development teams to address the difficulties of integrating reused components into different products. Originality/value This paper presents a tool for identifying interfaces when sources of knowledge do not allow the use of current methods.

A skill- and feature-based approach to planning process monitoring in assembly planning

Frequent changes in customer needs and large product variety are forcing manufacturing companies to move from mass production to mass customization. Customized production can be achieved by introducing reconfigurable production systems (RMS). The customized flexibility and several characteristics of RMSs provide many opportunities in terms of process and production planning. However, those characteristics greatly increase the complexity of the design and planning of production systems. This paper presents a decision support system relying on a skill-based approach to design a reconfigurable assembly line considering the planning of assembly processes and monitoring. The proposed decision aid system is modular in design and is composed of four modules. The main input data is a CAD model of a new product variant for the identification of the assembly and monitoring requirements. Besides, a current assembly system layout with its resource descriptions exists. In the first developed module, assembly-by-disassembly and a skill-based approach are used to generate different assembly plans. In the second module, feature recognition and skill-based approaches generate process monitoring alternatives. The third module uses a linear program (LP) that aims to minimize the total cost of workstation activation and reconfiguration, as well as cycle time, and to maximize the process quality of the assembly tasks. A user-based generative model design approach is applied to optimize the values of three objective functions. In the fourth and final module, a simulation of the optimized assembly plan allows either the validation of the assembly plan and process monitoring plan or initiates a new iteration due to their infeasibility. To further demonstrate how the proposed methodology works, some computational experiments are provided for two use cases.

A hierarchical assembly knowledge representation framework and microdevice assembly ontology

Microdevice assembly knowledge is dispersed in different product development phases, such as assembly design, assembly simulation and assembly process, and a lot of essential knowledge is implicit and heterogeneous. It is difficult for researchers and computer-aided systems to share and reuse different assembly knowledge quickly and accurately, leading to inefficient and inaccurate assembly process planning. To integrate and structurally represent the assembly design knowledge, assembly simulation knowledge and assembly process knowledge of microdevice, this paper proposes a hierarchical assembly knowledge representation framework and develops a microdevice assembly ontology. There are four layers in the framework, including the organizational structure, the structural relationship, the assembly accuracy, and the process characteristics. The assembly design knowledge that is integrated involves the basic properties of the assembly object as well as the spatial, mating, and assembly relationship, etc. Assembly simulation knowledge refers to the permissible range of assembly force and contact force. Knowledge of assembly processes comprises assembly sequence and operating method of the part. The microdevice assembly ontology is developed based on METHONTOLOGY, and implemented with Protégé. The corresponding SWRL rules have been established to inference the implicit knowledge in assembly design. An ignition target assembly knowledge model based on the microdevice assembly ontology is constructed. In the assembly task of the ignition target, engineers can quickly and accurately access the required assembly knowledge from the ignition target assembly knowledge model, thus verifying the integrity and validity of the microdevice assembly ontology.

Co-Optimization of Supply Chain Reconfiguration and Assembly Process Planning for Factory-in-a-Box Manufacturing

Abstract Factory in a box (FiB) is an emerging technology that meets the dynamic and diverse market demand by carrying a factory module on vehicles to perform on-site production near customers’ locations. It is suitable for meeting time-sensitive demands, such as the outbreak of disasters or epidemics/pandemics. Compared to traditional manufacturing, FiB poses a new challenge of frequently reconfiguring supply chain networks since the final production location changes as the vehicle carrying the factory travels. Supply chain network reconfiguration involves decisions regarding whether suppliers or manufacturers can be retained in the supply chain or replaced. Such a supply chain reconfiguration problem is coupled with manufacturing process planning, which assigns tasks to each manufacturer that impacts material flow in the supply chain network. Considering the supply chain reconfigurability, this article develops a new mathematical model based on nonlinear integer programming to optimize supply chain reconfiguration and assembly planning jointly. An evolutionary algorithm (EA) is developed and customized to the joint optimization of process planning and supplier/manufacturer selection. The performance of EA is verified with a nonlinear solver for a relaxed version of the problem. A case study on producing a medical product demonstrates the methodology in guiding supply chain reconfiguration and process planning as the final production site relocates in response to local demands. The methodology can be potentially generalized to supply chain and service process planning for a mobile hospital offering on-site medical services.

Assembly Sequence Planning Based on Hierarchical Model

With the rapid development of intelligent manufacturing technology and ultraprecision machining, assembly technology has attracted more and more attention. Assembly sequence is an important part of assembly process planning. However, assembly sequence is affected by many complex factors, such as the time required to assemble products, the geometric feasibility of assembly sequence, and other factors (tool replacement times and assembly direction change), so it is very challenging. In this paper, an assembly information model based on geometric features of parts is proposed. The model obtains the hierarchical information of the part through the segmentation and feature reconstruction of the part. Based on the influence of the contact surface between parts on the feasible motion domain and assembly domain, the assembly constraint relationship model is established. The objective function is constructed by changing the assembly direction, changing the assembly tools, and evaluating the assembly fit type. The geometrically feasible assembly sequence is optimized to obtain the optimal assembly sequence under the existing conditions. Taking a block, a secondary reducer spindle, and a cylinder as examples, the effectiveness of the method is verified.

A framework for planning a reconfigurable assembly system for press brake production

This article presents the design of a framework for the development of a reconfigurable assembly system (RAS) to facilitate the assembly of press brakes varieties. A consideration of press brake varieties is achieved by examining the parts taxonomy of press brakes from which a framework for assembly process plan is developed that considers all the types of press brakes identified from the classification. Also, a layout for the RAS is developed by considering a prototype of the major enabling equipment of the system which is a reconfigurable assembly fixture (RAF). The development of the assembly process plan and layout of the RAS enabled the design of a reconfiguration model for operation in the RAS. The designed assembly framework will provide: rapid and physical reconfiguration of the RAF in the RAS; generation of assembly sequence for press brake varieties; and allocation of assembly operations to assembly work cells in the system. [Submitted 27 May 2020; Accepted 3 December 2020]

Knowledge mapping of digital twin and physical internet in Supply Chain Management: A systematic literature review

Physical Internet (PI) is an open global logistics system of which components are hyperconnected for increased efficiency and sustainability. Digital twin (DT), referring to the virtual representation of a physical object, is well-perceived as a key driver in the development of PI-based Supply Chain Management (SCM). Due to the capabilities of real-time monitoring and evaluation of large-scale complex systems, significant research efforts have been made to exploit values of PI/DT in SCM. Despite this, the current literature remained largely unstructured and scattered due to a lack of systematic literature reviews to synergise research findings, analyse the evolution of research fronts and extract emerging trends in the field. To address this issue, the paper deploys a bibliometric knowledge mapping approach to provide a bird's eye view of the current research status in the PI/DT-SCM area. Using CiteSpace's keyword co-occurrence network, 518 journal articles are clustered into 10 key research streams on PI/DT applications in: job shop scheduling, smart manufacturing design, PI-based SCM, manufacturing virtualisation, information management, sustainability development, data analytics, manufacturing operations management, simulation and optimisation, and assembly process planning. Based on citation burst rate, keywords representing research frontiers of the PI/DT are detected and their temporal evolutions are discussed. Likewise, some identified emerging research trends are production process and system, robotics, computer architecture, and cost. Finally, seven future research directions are suggested, which emphasise on several PI/DT-related issues, including business ecosystem, sustainability development, SC downstream management, cognitive thinking in Industry 5.0, citizen twin in digital society, and SC resilience.

COMPUTER AIDED ASSEMBLY PLANNING USING MS EXCEL SOFTWARE – A CASE STUDY

The issue of planning assembly operations remains crucial decision-making area for many of manufacturing companies. It becomes particularly significant in case of small and medium enterprises that perform unit or small-scale production, where the option of applying specialized software is often very limited – both due to high purchase price, but also due to its applicability to single unit manufacturing, that is executed based on individual customer orders. The present article describes the possibility of applying the MS Excel spreadsheet in the planning of machine assembly processes. It emphasises, in particular, the method for using the spreadsheet in subsequent stages of the process, and the identification of possible causes that have impact on problems with the planning process. We performed our analysis on the basis of actual data from one of the machine industry enterprises that manufactures in central Poland.

KGAssembly: Knowledge graph-driven assembly process generation and evaluation for complex components

ABSTRACT The semantic information of process documents for the assembly of complex components plays an important role in the guidance of assembly operations and the feasibility evaluation of process plans. There are many types of semantic elements contained in assembly process documents. The semantic relationship between assembly elements is complex. Additionally, there is a lack of effective modeling method to deal with the implicit associative semantic knowledge that exists among existing assembly process cases. In this case, it is a great challenge to use the professional knowledge in assembly process documents to guide the intelligent decision-making of assembly process planning and the intelligent analysis of assembly process enforceability evaluation. In this paper, a knowledge graph-driven assembly process generation and evaluation method for complex components is proposed. An APKG (assembly process knowledge graph) model is built. A distributed graph embedding-based model SKGCN (sequence knowledge graph convolutional network) is designed to generate assembly process planning. Furthermore, model and knowledge dual-driven evaluation method for assembly sequences is presented. It provides assembly expert knowledge support for the evaluation method of interference detection of assembly sequence based on point cloud assembly feature recognition. Finally, the approach is evaluated by assembling an aero-engine compressor rotor.

Design of Integrated Computer Aided Process Planning and Bill of Material in Industry 4.0 Environment

Computer aided process planning (CAPP) has been widely used as an application that is able to plan the process in manufacturing with computer technology supporting. In its implementation, the process planning stage often requires complete data/information input regarding manufacturing products that will go through several process and operations. In the assembly process for example, before planning what process and operations will be carried out on a parts, the assembler must know the specifications and product structure, so that the assembly planning process becomes directed. The purpose of this research is to perform the design of integrated computer aided process planning and bill of material as the product structure that can support the planning process activities in manufacturing area and also suitable with industry 4.0 environment whereas the rapid changes in the information and communication technologies have broken the boundaries between virtual reality and the real world.

Digital twin support for laser-based assembly assistance

Flexibility and versatility in production put high demands on the planning, simulation and ramp-up of assembly systems and processes. For this purpose, a digital twin of a laser-based assembly assistance system for manual mounting tasks was developed, implemented and analyzed. A capability model was elaborated using quantitative and qualitative studies. The capability model was realized as a Unity 3D model. In the augmented reality implementation using the Microsoft HoloLens users can control the digital twin through hand gestures and voice control. The implementation shows that the digital twin of the laser-based assembly assistance supports the planning, simulation and training of employees at the shop floor.

Architecture Design of Intelligent Assembly System Based on Complex System

For complex system and product, the virtual and intelligent assembly system can short the designing and manufacturing time effectively, especially for administration of life cycle of product, it can provide the digital models for different period using. In this paper, the intelligent assembly system architecture was designed which includes three-layers, application layer, data layer, and output layer. By using this intelligent assembly system the virtual assembly of complex system products is realized. Then, the framework of intelligent assembly information modelling was designed further which includes geometric information, assembly constraint information, and assembly relationship information. This assembly information model can not only express the connection between assembly parts and assembly relationships, but also provide information sources and acquisition mechanisms for assembly process planning. At last, an example of product assembly is presented which includes 3D models analysis and attribute set for simulation, the intelligent assembly function is accomplished in the end.

Worker assistance systems and assembly process maturity in the prototype and pre-series production

In order to minimize time-to-market, the development and planning of automotive assembly processes needs to be conducted in early product development stages under high uncertainty, with frequent changes and increasing time and cost pressure. Nonetheless, the resulting processes at the time of handover to the series production need to be mature, thoroughly tested and optimized to minimize problems and delays in the ramp-up. Recently, assistance systems for the manual assembly have received extensive attention in research and practice. However, they were almost exclusively applied to the series production, while little regard was dedicated to the potential such systems can offer for development and planning. Therefore, this paper presents an approach to leverage worker assistance systems for the assembly process development and evaluation during the prototype assembly in series development. A general approach and design for such a system is described and observations from a company are presented where a corresponding solution was piloted.

Research on Hull Assembly Process Planning Based on Rule Reasoning

Currently, hull assembly process is mainly dependent on experience, and lack of normative standard. In this paper, hull structure for assembly features is systematically studied, and an assembly sequence planning method based on Rule Reasoning is proposed. Firstly, assembly feature and sequence expression of hull structure is analyzed and the constraint relation of connection information is described. Secondly, the relationship between established structures and the constraint function is designed. Setting the double bottom of the ship as an example, hull assembly sequence is obtained based on geometric constraints and optimized by the fuzzy evaluation method and finally realized the computer aided evaluation of the hull assembly sequence.

A review: virtual assembly of flexible cables based on physical modeling

PurposeCables are widely used, and they play a key role in complex electromechanical products such as vehicles, ships, aircraft and satellites. Cable design and assembly significantly impact the development cycle and assembly quality, which is be-coming a key element affecting the function of a product. However, there are various kinds of cables, with complex geo-metric configurations and a narrow assembly space, which can easily result in improper or missed assembly, an unreasonable layout or interference. Traditional serial design methods are inefficient and costly, and they cannot predict problems in installation and use. Based on physical modeling, computer-aided cable design and assembly can effectively solve these problems. This paper aims to address virtual assembly (VA) of flexible cables based on physical modeling.Design/methodology/approachMuch research has focused recently on virtual design and assembly-process planning for cables. This paper systematically reviews the research progress and the current state of mechanical models, virtual design, assembly-process planning, collision detection and geometric configuration and proposes areas for further research.FindingsIn the first instance, the main research groups and typical systems are investigated, followed by extensive exploration of the major research issues. The latter can be reviewed from five perspectives: the current state of mechanical models, virtual design, assembly-process planning, collision detection and geometric configuration. Finally, the barriers that prevent successful application of VA are also discussed, and the future research directions are summarized.Originality/valueThis paper presents a comprehensive survey of the topics of VA of flexible cables based on physical modeling and investigates some new ideas and recent advances in the area.