Assembly Automation

Precision assembly systems for medical devices : Table of Contents

Christine Connolly — Mon Sep 28 08:59:09 BST 2009

Abstract:
Purpose – The purpose of this paper is to describe the approach and technology of various companies making automated assembly equipment for medical devices. Design/methodology/approach – The structure of the medical device assembly market is introduced, and the expertise and applications of a small company working in the intermediate production market is described. The modular approach of Mikron Assembly Technology is examined in detail. Finally, a company making machines for very high-volume medical device assembly is considered. Findings – The development of new medical device products is dependent on many stages of verification and validation, providing niches for assembly machinery builders of very different sizes. Reliability and precision of assembly is vital for the correct operation of the products throughout their lifetime. Testing and inspection stations form an integral part of many assembly lines, to provide a high degree of process security and traceability. Originality/value – This paper reveals the nature of the medical device market and shows how three different-sized assembly machinery manufacturers operate in the sector.

Disassembly processes with disassembly matrices and effects of operations : Table of Contents

Yuan Mao Huang, Yu-Chung Liao — Mon Sep 28 08:59:09 BST 2009

Abstract:
Purpose – The purpose of this paper is to enhance the method developed by previous researchers. In addition to using the combined interference matrix, the combined connection matrix and the combined contact matrix of product components, the disassembly sequence matrix and the combined instability matrix with platform to evaluate instability of sub-assemblies are built, and effects of changes of sub-assembly disassembly directions or tools and the effect of gravity are considered to obtain the best disassembly sequence for a product with many components. A computer program is generated and results of two cases are compared with those of the available studies. Design/methodology/approach – The methodology includes the combined interference matrix, the combined contact matrix and the combined connection matrix of components for a product. The combined instability matrix of sub-assemblies, changes of sub-assembly disassembly direction or tools, and the effect of gravity during operation are considered. The binary number system is used to simplify relations among components of a product. Findings – This methodology enhances the existing method and software is generated. Results of two cases are compared and show the same optimum disassembly processes as those obtained from other researchers. Research limitations/implications – All matrices are defined by the directions of x, y and z with three axes perpendicular to each other. The computer program generated cannot be used for a product with components that must be disassembled in the directions different from the axes. Practical implications – Two cases are used to investigate feasibility of the proposed methodology with the computer program generated. The first one is an electric drill, and the second one is a flash lighter. Originality/value – The methodology described in this paper is feasible for study of disassembly processes of products. The software generated can be used to obtain the optimum disassembly process of products.

Pneumatic modules for automatic applications : Table of Contents

Christine Connolly — Mon Sep 28 08:59:09 BST 2009

Abstract:
Purpose – The purpose of this paper is to explore pneumatic components and the applications they address. Design/methodology/approach – The extensive range of pneumatic grippers and actuators from various manufacturers is presented. An example of an end-user pneumatic handling solution is given. Applications are then examined in plastics, mortise lock manufacture and food and pharmaceutical industries. Findings – Pneumatic components are long lasting and reliable, giving tens of millions of operational cycles. Gimatic makes modular components that are particularly attractive for direct use by end-users. Festo is already introducing a range of pneumatic products complying with the European Union safety directive to be introduced in December 2009. Originality/value – This paper illustrates the versatility and reliability of pneumatic elements in automatic assembly operations.

Sensor placement strategy for fixture variation diagnosis of compliant sheet metal assembly process : Table of Contents

Sun Jin, Kuigang Yu, Xinmin Lai, Yinhua Liu — Mon Sep 28 08:59:09 BST 2009

Abstract:
Purpose – The purpose of this paper is to focus on optimal sensor placement for the fixture variation diagnosis of compliant sheet metal assembly process. Fixture variations are the main sources for complex automotive body dimensional failures. An effective measurement strategy can help exactly and timely diagnose these fixture variations. Research on sensor placement strategy of compliant sheet metal assembly process is not much stated formerly. Design/methodology/approach – The impact principle of fixture variations is analyzed to set up the relationship between the assembly variation and fixture variations applying the method of influence coefficients and the effective independence (EI) method is used to find the optimal sensor positions based on the impact principle analysis of fixture variations. Findings – The obtained fixture variation sensitivity matrix describes the influence of fixture variations to compliant sheet metal assembly variation and can be used for diagnosing fixture variations. The EI method can effectively solve the optimal sensor positions for compliant sheet metal assembly by a case demonstration. Originality/value – The proposed method can solve the sensor placement of online assembly station for diagnosing fixture variations. It takes the compliant characteristics of sheet metal parts into account and the sensor information has much greater diagnosability than that from applying other methods.

Measuring the assembly quality from the operator mistake view: a case study : Table of Contents

Qiang Su, Lei Liu, Shengjie Lai — Mon Sep 28 08:59:09 BST 2009

Abstract:
Purpose – The purpose of this paper is to focus on the assembly quality of copier products, specifically, concentrating on the prediction of the operator-induced assembly defect. Design/methodology/approach – Based on the Shibata model, the design-based assembly complexity is redesigned. And the Sony Standard Time is replaced by the Fuji Xerox Standard Time in the calculation of the process-based assembly complexity. Furthermore, different correlation functions are attempted and comparatively studied in the regression analysis. Thereby, a new defect rate prediction model is proposed and validated with three copier assembly cases. Findings – The new proposed model is much more accurate and stable in the human-induced assembly defect prediction in copier production. Practical implications – The proposed model can be used to ensure the assembly quality by removing potential defects at the structure and process design stages. Meanwhile, with this model, the interactions between the engineers and designers can be more effective. Originality/value – This paper presents a novel assembly defect rate prediction model for copier assembly quality management.

Effectiveness of epoxy staking of fasteners in aerospace applications : Table of Contents

S. Salmon, M. Swank, G.D. Janaki Ram, B.E. Stucker, J.A. Palmer — Mon Sep 28 08:59:09 BST 2009

Abstract:
Purpose – The purpose of this paper is to investigate the effectiveness of locking or staking of fasteners with epoxy material systems to prevent loss of preload in aerospace environments. Design/methodology/approach – A quantitative experimental method is adopted to evaluate epoxy material systems for staking of fastener assemblies subjected to varying dynamic and thermal loads. A statistical design of experiments is employed to probe specific design parameters. Findings – Results show that epoxy application can provide satisfactory fastener locking under a variety of service conditions. It is found that: Epon 828 epoxy provides superior fastener locking compared to 3M Scotch-Weld Epoxy 2216; epoxy application around screw threads is more effective than application around screw head; and abrading the plate surfaces with 180 grit SiC paper is not an effective or useful surface preparation technique. Research limitations/implications – The paper is limited to two commercial epoxy material systems and does not consider important qualitative considerations for industrial use such as cure time and viscosity. Practical implications – This and future paper may form the basis of new standards for epoxy staking in the global aerospace industry. Originality/value – This paper is believed to be one of the very few original experimental studies of fastener staking available in the open literature.

Investigation of butt joint failure mode in sofa frame : Table of Contents

Vipul Patel, S.H. Masood, Tim Waterman — Mon Sep 28 08:59:09 BST 2009

Abstract:
Purpose – The purpose of this paper is to investigate the static behavior of different type of butt joints for application in a timber sofa furniture frame. In timber sofa structure, butt joints are commonly used between plywood and hardwood members but they are normally designed without any regard to the effect of grain directions of the wood members on the joint strength. The focus of the paper is to look at the effect of grain directions on the wooden member properties and on the strength of the butt joint in order to understand the failure mode to establish a more durable and effective sofa butt joint than the one normally used by the manufacturers. Design/methodology/approach – Experiment tests are conducted to determine the mechanical properties of joint members, the maximum load-carrying capacity of the butt joints, and the types of the failure in the joints in relation to different grain orientations under transverse loading conditions. Plywood and hardwood members are used in construction of the joint tests. Four types of butt joints are constructed with different condition of grain orientation, glue, and screw used in the joint members. The specimens are tested by fixing the plywood member and applying a transverse load to the hardwood member to simulate the conditions in the sofa frame. Findings – Result shows that butt joint with vertical grain orientation and joint with two screws and glue have the maximum load-carrying capacity compared to the other three cases and compared to the current joint type used in the existing sofa frame design. Originality/value – The paper is of value to furniture manufacturing industry, in which furniture members and joints are usually over-designed without regard to grain orientations or applying sound engineering techniques.

An expert system for automatic design-for-assembly : Table of Contents

David Sanders, Yong Chai Tan, Ian Rogers, Giles E. Tewkesbury — Mon Sep 28 08:59:09 BST 2009

Abstract:
Purpose – The purpose of this paper is to present a multi-expert system that can provide designers with suggestions for improvement. The multi-expert system can analyse a design and provide designers with ideas for changes to designs at an early stage in order to improve assembly later in the manufacturing process. Design/methodology/approach – The whole system consists of four expert systems: computer-aided design (CAD) expert, automated assembly expert, manual assembly expert and design analysis expert. The design analysis expert includes a sub-system to collate the information from the assembly experts and to provide costs and advice. Findings – The paper finds that the approach and the systems can reduce manufacturing costs and lead times. Research limitations/implications – A knowledge-based reckoning approach to design-for-assembly automation is used. The approach and systems can reduce manufacturing costs and lead times. The system can estimate assembly time and cost for manual or automatic assembly and select suitable assembly techniques. Practical implications – The system can estimate assembly time and cost for manual or automatic assembly and select a suitable assembly technique. Originality/value – The new system models assembly, product and process design using a natural approach for capturing intelligence. The new approach categorised automated assembly and manual assembly into separate individual experts. Intelligence and knowledge from each is captured and embedded within the individual expert that represented the process. This approach enabled greater flexibility and made the sub-systems easier to modify, upgrade, extend and reuse.

RFID technology in product/part tracking during the whole life cycle : Table of Contents

Mon Sep 28 08:59:09 BST 2009

Abstract:
Purpose – The purpose of this paper is to present a new way for identification of products/parts and their tracking during the whole life cycle, from the manufacture and assembly phase to the disassembly phase. Design/methodology/approach – Radio frequency identification (RFID) technology is applied on a chosen product, an in-mould labelling (IML) robot. Findings – This paper discusses a case study that highlights the use of RFID as automatic identification technology, especially in the processes of assembly/disassembly of the IML robot. The application can be expanded onto any kind of product, with the exception of some life cycle phases that are specific for a particular product. Practical implications – The paper gives an example of how RFID technology can actually be realized in the case of the IML robot to improve the quality of tracking its main components. Originality/value – The users have the possibilities to access and analyze information about the products/parts during their cycle.

The fast-moving world of MEMS technology : Table of Contents

Robert Bogue — Mon Sep 28 08:59:09 BST 2009

Abstract:
Purpose – The purpose of this paper is to provide a technical review of silicon micro-electromechanical systems (MEMS) technology and its applications. Design/methodology/approach – Following an introduction, the paper describes silicon MEMS fabrication and assembly techniques, considers a selection of commercially important products and their applications and concludes with a brief review of power MEMS research. Findings – Silicon MEMS fabrication technology is derived from techniques used in semiconductor manufacture and has yielded a diverse and ever-growing range of sensors, actuators and other miniaturised devices that find applications in a multitude of industries. Originality/value – This paper provides a detailed technical review of MEMS technology and its applications.