fea integration in the tolerance analysis using skin model shapes

Abstract Many research works on tolerance analysis have been carried out in the last thirty years. In this paper, a new idea is proposed, aiming to investigate the effect of form error and mechanical behavior of parts on the stack-up result by combining the recent novelties on the tolerance analysis of rigid and flexible bodies. The real parts are simulated considering the non-nominal Skin Model Shape and the mechanical properties in order to simulate the assembly of a realistic case study. A manufacturing signature model to generate the features with geometric deviations and Finite Element Analysis (FEA) are used

The case of Foxconn in Turkey: benefiting from free labour and anti-union policy

Starting from the 2000s Foxconn invested in Czechia, Slovakia, Hungary, Russia and Turkey, implementing a territorial diversification strategy aimed at getting nearer to its end markets. This chapter investigates the development of Foxconn in Turkey where the multinational owns a plant with about 400 workers. A few kilometres from the city of \uc7orlu and close to highways, ports and international airports, the plant enables Foxconn to implement an efficient global supply chain. We illustrate this process by examining the company\u2019s localisation within a special economic zone, underlining the economic advantages derived from such a tax regime, bringing labour costs down to the Chinese level and obtaining proximity to European, North African and Middle East customers, thus lowering logistic costs. We also analyse the roles of labour flexibility and trade unions. In order to impose far-reaching flexibility on its workers Foxconn put in place a range of strategies, including an hours bank system, multitask operators and the recruitment of apprentices thanks a special programme funded by the state. We show how these have been crucial for Foxconn\u2019s just-in-time production contrasting its labour turnover problem. Finally, we highlight how the company has been able to implement a flexible working pattern, weaken the trade unions and undercut workers\u2019 opposition, thanks to favourable labour laws approved by successive governments in the past thirty years

Flexible workforces and low profit margins: electronics assembly between Europe and China

This book investigates restructuring in the electronics industry and in particular the impact of a \u2018Chinese\u2019 labour regime on work and employ - ment practices in electronics assembly in Europe.1 Electronics is an extremely dynamic sector, characterized by an ever-changing organi - zational structure, as well as cut-throat competition, particularly in manufacturing. Located primarily in East Asia, electronics assembly has become notorious for poor working conditions, low unionisation and authoritarian labour relations. However, hostile labour relations and topdown HR policies are not unique to East Asia. They have become associated with the way the sector is governed more broadly, with a number of Western companies also coming to rely on such practices

Introduction

This book investigates restructuring in the electronics industry and in particular the impact of a \u2018Chinese\u2019 labour regime on work and employ - ment practices in electronics assembly in Europe.1 Electronics is an extremely dynamic sector, characterized by an ever-changing organi - zational structure, as well as cut-throat competition, particularly in manufacturing. Located primarily in East Asia, electronics assembly has become notorious for poor working conditions, low unionisation and authoritarian labour relations. However, hostile labour relations and topdown HR policies are not unique to East Asia. They have become associated with the way the sector is governed more broadly, with a number of Western companies also coming to rely on such practices

Active Self-Assembly of Algorithmic Shapes and Patterns in Polylogarithmic Time

We describe a computational model for studying the complexity of self-assembled structures with active molecular components. Our model captures notions of growth and movement ubiquitous in biological systems. The model is inspired by biology's fantastic ability to assemble biomolecules that form systems with complicated structure and dynamics, from molecular motors that walk on rigid tracks and proteins that dynamically alter the structure of the cell during mitosis, to embryonic development where large-scale complicated organisms efficiently grow from a single cell. Using this active self-assembly model, we show how to efficiently self-assemble shapes and patterns from simple monomers. For example, we show how to grow a line of monomers in time and number of monomer states that is merely logarithmic in the length of the line. Our main results show how to grow arbitrary connected two-dimensional geometric shapes and patterns in expected time that is polylogarithmic in the size of the shape, plus roughly the time required to run a Turing machine deciding whether or not a given pixel is in the shape. We do this while keeping the number of monomer types logarithmic in shape size, plus those monomers required by the Kolmogorov complexity of the shape or pattern. This work thus highlights the efficiency advantages of active self-assembly over passive self-assembly and motivates experimental effort to construct general-purpose active molecular self-assembly systems

Implementation of automated assembly

Research has shown that about 60 - 80% wealth producing activities is related to manufacturing in major industrial countries. Increased competition in industry has resulted in a greater emphasis on using automation to improve productivity and quality and also to reduce cost. Most of the manufacturing works such as machining, painting, storage, retrieval, inspection and transportation have changed to automation successfully, except assembly. Manual assembly is predominant over automatic assembly techniques due to inherent assembly problem and the fact that the assembly machines lack the innate intelligence of human operator and lack sufficient flexibility to changeover when product designs and market demands change. With the advent of flexible manufacturing systems, which involve very large capital costs and complex interactions. For the reduction the risk of the investment and analyze the system, simulation is a valuable tool in planning the systems and in analyzing their behavior, and get the best use of them. This thesis applies animation techniques to simulate an automatic assembly system. In chapter 1 to 9, we cover some of the fundamental concepts and principles of automatic assembly and simulation. Some manufacturers put the subject of part orientation first on their list of priorities; but design for assembly (DFA) techniques have proven extremely valuable in developing better assembly techniques and ultimately, better products. We discuss DFA in chapter 1, part feeding and orientation in chapter 2. Chapter 3, 4 and 5 are concerned with assembly process, machines and control system, respectively. Annual sales for industrial robots have been growing at the rate of about 25 percent per year in major industrial countries, we review the robot application in chapter 6. The cost of material handling is a significant portion of the total cost of production, material storage uses valuable space and consumes investment, we cover these two topics in chapter 7 and 8. Chapter 9 is concerned with simulation. In chapter 10, 11,12 and 13, we implement a software package IGRIP to build a model of an automatic assembly system and analyze the result

Deployment/retraction ground testing of a large flexible solar array

The simulated zero-gravity ground testing of the flexible fold-up solar array consisting of eighty-four full-size panels (.368 m x .4 m each) is addressed. Automatic, hands-off extension, retraction, and lockup operations are included. Three methods of ground testing were investigated: (1) vertical testing; (2) horizontal testing, using an overhead water trough to support the panels; and (3) horizontal testing, using an overhead track in conjunction with a counterweight system to support the panels. Method 3 was selected as baseline. The wing/assembly vertical support structure, the five-tier overhead track, and the mast-element support track comprise the test structure. The flexible solar array wing assembly was successfully extended and retracted numerous times under simulated zero-gravity conditions

Self-Assembly in Mixtures of Polymers and Small Associating Molecules

The interaction between a flexible polymer in good solvent and smaller associating solute molecules such as amphiphiles (surfactants) is considered theoretically. Attractive correlations, induced in the polymer because of the interaction, compete with intra-chain repulsion and eventually drive a joint self-assembly of the two species, accompanied by partial collapse of the chain. Results of the analysis are found to be in good agreement with experiments on the onset of self-assembly in diverse polymer-surfactant systems. The threshold concentration for self-assembly in the mixed system (critical aggregation concentration, cac) is always lower than the one in the polymer-free solution (critical micelle concentration, cmc). Several self-assembly regimes are distinguished, depending on the effective interaction between the two species. For strong interaction, corresponding experimentally to oppositely charged species, the cac is much lower than the cmc. It increases with ionic strength and depends only weakly on polymer charge. For weak interaction, the cac is lower but comparable to the cmc, and the two are roughly proportional over a wide range of cmc values. Association of small molecules with amphiphilic polymers exhibiting intra-chain aggregation (polysoaps) is gradual, having no sharp onset.Comment: 21 pages, 5 figures, RevTex, the published version, see also cond-mat/990305

The integrated approach of water hyacinth control on Lake Kainji: with special regard to the design, construction and installation of a water hyacinth barrier across the River Niger

This document lists the undesirable effects of water hyacinth (Eichhornia crassipes) on fisheries in Lake Kainji (Nigeria) and the integrated Water Hyacinth Control Programme in its ongoing fisheries management and development activities on the lake. Special regard is given to the design, construction and installation of a water hyacinth barrier across the River Niger. (PDF contains 44 pages