Design Of Assembly Systems Research Articles

Design and scheduling of flexible assembly systems for large products: A simulation study

Abstract Manufacturers of large products are increasingly considering the use of flexible assembly systems to improve the efficiency of their assembly operations, especially where many different products are assembled on the same assembly line. The assembly of large products usually involves some large component parts. The complications of mating such components with the partially assembled unit must be considered in the design and the operation of the flexible assembly system. In this paper, we present results of a simulation study that was motivated by a major automobile company. The study investigates capacity planning issues (number of machines and buffers) and scheduling strategies to facilitate the component mating process.

Criteria for Optimum Layout Design of Assembly Systems

The performance and the return of investment for Assembly Systems are very much dependent on the throuput of the system, on the utilisation of the more important components (robots, AGVS, etc.) and on the reusing of these components in different configurations. The paper deals with the criteria for optimum layout design and how simulation is used to validate the criteria.

Contribution to Computer-Aided Design of Flexible Assembly Systems

In this paper, the authors present a complete stategy to design a flexible assembly system for any product. The basic idea is to divide the assembly actions in two classes; the dedicated ones ( specific of the product) and the positional ones ( specific of the assembly process). The proposed method includes an algorithm which generates all the valid combinations of the dedicated actions, in the form of assembly trees ; the awkward ones are then rejected by the introduction of some set of constraints. The remaining trees are then transformed by the assignment of equipments to its different nodes, which introduces the positional actions. A comparison of the different solutions is then achieved by the way of a simulation.

Database Support in Workcell Design

This paper deals with the information problems arising in manufacturing and design environments. These problems are caused by more complex data structures, more varied modes of user and tool interaction, and by the need to provide fast and flexible access means to the information.The lack of tools to cope with these problems is one of the main reasons why integrated manufacturing is still a relatively far-fetched goal. Without trying to attain integration of the whole factory, information systems to support the communication and coordination of the activities used inside a department or engineering area, such as design, analysis, or software development, can be defined and implemented. One such system, used as a central database in a Flexible Assembly System design application, is presented in this paper. The system has been implemented and tested as part of ESPRIT Project 623, “Operational Control for Robot System Integration into CIM”, demonstrating the feasibility of efficient information sharing and reliable data management.

The design and development of an automated DFA system

Abstract This paper presents the design and development of an automated system to assist with Design for Assembly (DFA) analysis. The system is designed to accept information on alternative assemblies using DFA metaphors. Statistics are calculated for these assemblies so as to evaluate their assemblability. The alternative assemblies and improvements in any assembly design are evaluated using these statistics. A binary tree data structure is used in the DFA system to represent the design data. This structure is implemented by a linked method with three links in each tree node. This allows any arbitrary tree to be represented efficiently, and it also allows for unpredictable tree growth and easy tree manipulation. The user interface of the DFA system is managed by the “User Interface Management System”, that achieves direct and fast control of the screen by directly accessing the video memory.

On the Reasonable Assembly Work Amount to the Kinds and Number of Parts : Design of Mass-Production Assembly System

On the Reasonable Assembly Work Amount to the Kinds and Number of Parts : Design of Mass-Production Assembly System

A framework for automated mechanical assembly planning

In this paper, a framework for automated mechanical assembly planning is discussed. The paper addresses three major issues: conceptual assembly design representation, assemblability analysis, and assembly plan generation. The objective of the study is to develop an effective way to model and plan for the assembly of a product. It is hoped that noty assembly planning can be automated, but also the feedback provided by the planning system can help to improve the design from a manufacturing point of view. Since the feasibility of automating the assembly plan generation depends on whether the assembly design is represented in a complete, unambiguous, and easy to use form, the design representation is the first issue addressed. In order to ensure the “manufacturability” of an assembly, the assemblability of the design must be analyzed at the early design stage. This analysis can be viewed as a rough planning. It provides the designer a quick feedback, thus the design can be changed before it is finalized. Before the actual assembly can be conducted, a detailed assembly plan must be prepared. Such an assembly plan is used for shop scheduling, and sometimes assembly system design.

A comprehensive literature review and analysis of the design, balancing and scheduling of assembly systems

SUMMARY This paper reports the results of a comprehensive review and analysis of the assembly line balancing literature. Quantitative developments and qualitative issues are addressed at both the strategic and tactical levels. The numerous quantitative and qualitative factors which the literature mentions could impact the design, balancing and scheduling of assembly systems are organized into an eight-level hierarchical, factor/decision taxomony. This comprehensive taxonomy is used to assess our progress in assembly system design and operation. Finally, from the results of the literature review and progress assessment, suggestions for future research on socio-technical assembly systems are offered.

Flexible step‐by‐step assembly automation

The correct choice of basic assembly system design is essential to provide the flexibility to cope with market demands. Bruno Lotter explains.

Equipment selection and task assignment for multiproduct assembly system design

A multiproduct assembly system produces a family of similar products, where the assembly of each product entails an ordered set of tasks. An assembly system consists of a sequence of workstations. For each workstation, we assign a subset of the assembly tasks to be performed at the workstation and select the type of assembly equipment or resource to be used by the workstation. The assembly of each product requires a visit to each workstation in the fixed sequence. The problem of system design is to find the system that is capable of producing all the products in the desired volumes at minimum cost. The system cost includes the fixed capital costs for the assembly equipment and tools and the variable operating costs for the various workstations. We present and illustrate an optimization procedure that assigns tasks to workstations and selects assembly equipment for each workstation.

Contribution to the Design of Small Parts Assembly System

Summary Small parts assembly system design is very difficult engineering activity. The activity starts with system analysis of assembly liability of product as term of reference for design of assembly transfer center. Referring to the given conditions automatic assembly with inspection has been designed. The developed control system is based on pneumatic control technology, due to the specificity of product components. Special attenation has been paid to feeding small plastic parts. The realized assembly system for small valve consisting of eight parts illustrates the whole approach.

Design of assembly systems

An iterative procedure is presented to solve the process planning problem for robotic assembly systems. The procedure consists of two levels: Level 1—station loading and Level 2—operation scheduling. The main task is to select and load stations and to schedule operations so as to minimise the overall cost of the system with respect to several constraints: (i) time constraints to avoid the bottleneck as well as idle time due to given production ratio, (ii) transportation constraints to avoid returns of the processed assembly to the same station. The procedure is illustrated on the example of modernisation of the system for railcar sides assembly.

Distributed manufacturing systems

SUMMARYIn the context of computer-integrated manufacture (CIM), the paper describes the need for flexible “intelligent” machinery and the need for integrated and distributed software. Methodologies in obtaining appropriate solutions are discussed and related to two major SERC sponsored research programmes at Loughborough University, which concern (i) the design of a family of mechanical and control system modules to allow robots to be configured with user defined kinematic and dynamic properties, and (ii) the design of distributed hardware and software structures, based on internationally accepted communication protocols, to allow FAS's to be produced.In batch manufacture today's increased demand for product variety, requiring reduced lead times and work in progress, the need arises for computer-integrated manufacture (CIM). Similarly, in many conventional continuous flow manufacturing processes dramatic improvements in plant efficiency can be achieved by linking shop floor computer systems with computers performing management and design functions.Considerable research and development work has centred on flexible manufacturing systems (FMSs)3−1 which conventionally relate to metal cutting environments. Similarly the labour intensive nature of assembly operations has led to considerable interest in the design of flexible assembly systems.3.4 The principles embodied in FMS and FAS are translatable, being applicable to most manufacturing environments.To achieve flexible integrated manufacturing two major requirements can be identified, viz. (i) the need for flexible “intelligent” machinery, and (ii) the need for integrated but distributed software systems. This paper will consider future trends in (i) and (ii).

Computer Aided Design of Flexible Assembly Systems

A strongly interactive software package is being developed to guide an engineer through the design of an assembly system. Four main parts can be distinguished: - An economical screening to determine which assembly method is likely to be most economical. - A technical analysis of the product, based on Boothroyd's “Design for Assembly”, in which feeding, gripping and insertion of each component is considered. - Task assignment and line balancing. - Computer aided layout of the assembly system (future).

Design and optimization of multi-echelon assembly networks: Savings and potentialities

In the last decade considerable attention has been paid to the analysis and optimization of multi-echelon assembly networks. Research contributions in this field are mainly focussed on the determination of optimal batch quantities. In this paper two other issues concerning multi-echelon assembly networks are also discussed. The first point concerns the notion of flexibility in assembly operations. Flexibility can be achieved by spending on assembly engineering to cut set-up costs. The second point has to do with design of multi-level assembly systems. Furthermore the notion of minimum network leadtime is introduced. This turns out to be (besides minimal average cost per period) a performance indicator of considerable importance. To conclude an existing Philips product (called medsys) is presented in order to illustrate the ideas discussed in this paper.

An Experimental Study of the Kinetics and Thermodynamics of Water Vapour Dissolution in a CaO–SiO2–MgO Slag

AbstractThis paper describes a thermogravimetric technique which allows precise measurements of both the kinetics of absorption and desorption, and the solubility of water vapour in liquid slags. A detailed discussion is given of experimental aspects including calibration procedures and the design of the furnace assembly and gas flow system. Measurements using a CaO-MgO-SiO2 slag indicate that the solubility is independent of temperature and varies directly as the square root of the partial pressure of water vapour. This square root relationship agrees with previously published data. However, the present data are about five times more precise than those determined in the past using conventional experimental techniques. Values for the apparent diffusion coefficients are between 1.4 and 2.1 × 10−4 cm2 S−1 for temperatures in the range 1475–1550°C. Resume Cet article decrit une technique thermogravimetrique qui permet des mesures precises a la fois de la cinetique d'absorption et de desorption et de la solub...

A Practical Computer Program for the Design of Assembly Systems

A Practical Computer Program for the Design of Assembly Systems

The Development of a Three-Micron Absolute Main Oil Filter for the T53 Gas Turbine

This paper describes the development of the first known successful three-micron absolute main oil filter for an aircraft gas turbine lubrication system, replacing the 40-micron nominal filter on the Avco Lycoming T53 engines. The new disposable elements, running approximately 300 hours without clogging, provide a much cleaner lubrication system and have eliminated requirements for 25 hour filter inspections and 100 hour oil drains. Despite past filter experience, the clean pressure drop through the new filter is close to that of the 40-micron unit. Two benefits of the new elements are described. The first is prevention of the wear caused by the abrasive action of oil containing fine one to five-micron particles. Once these particles are removed, the system stays clean for hundreds of hours. This period is not shortened unless lube system component failures, engine teardowns and rebuilds, or frequent oil changes occur. The second benefit is the marked absence of oil degradation with clean oil over long drain intervals. The paper describes the design of the filter assembly and indicator system, bench testing, and the 6000 hours of engine testing of the filter prior to its proposed incorporation into the production engines.