173 research outputs found

    A Production Planning Model for Make-to-Order Foundry Flow Shop with Capacity Constraint

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    The mode of production in the modern manufacturing enterprise mainly prefers to MTO (Make-to-Order); how to reasonably arrange the production plan has become a very common and urgent problem for enterprises’ managers to improve inner production reformation in the competitive market environment. In this paper, a mathematical model of production planning is proposed to maximize the profit with capacity constraint. Four kinds of cost factors (material cost, process cost, delay cost, and facility occupy cost) are considered in the proposed model. Different factors not only result in different profit but also result in different satisfaction degrees of customers. Particularly, the delay cost and facility occupy cost cannot reach the minimum at the same time; the two objectives are interactional. This paper presents a mathematical model based on the actual production process of a foundry flow shop. An improved genetic algorithm (IGA) is proposed to solve the biobjective problem of the model. Also, the gene encoding and decoding, the definition of fitness function, and genetic operators have been illustrated. In addition, the proposed algorithm is used to solve the production planning problem of a foundry flow shop in a casting enterprise. And comparisons with other recently published algorithms show the efficiency and effectiveness of the proposed algorithm

    Concept Development to Control Non-value Added Logistical Costs in a Primary Aluminium Casthouse by Interfacing Linear Optimization and Simulation

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    After the financial crisis in 2008, demand reduction especially from the automotive in-dustry and changes in CO2 tax regulations which increased the energy prices the alu-minium industry forced to review and reduce its operational expenditure. High energy consumption in the production of primary aluminium dedicates most of the efforts on technological development onto the electrolysis unit. However, other units of a smelter also have the potential to improve their operational efficiency. In this thesis, the focus is on the casthouse unit of the smelter. The aim of this research is to quantify and reduce the non-value added logistical costs in the aluminium industry’s supply chain. This re-search attempts to simulate the internal supply chain of a primary aluminium casthouse and identify the wastes by implementing a lean thinking approach. After highlighting the possible improvements, optimization models attempt to reduce these wastes which create non-value added costs to the system. This concept is further developed by inter-facing the simulation model with the optimization model to validate the improvements. The success of the concept is tested by measuring the reduction in redundant logistical costs of a case study founded on the real casthouse specifications. Scenarios are defined to analyze the casthouse supply chain under different perspectives. The potential gain of the new concept is verified by applying it to these scenarios. In conclusion, the results analysis of the scenarios indicates the success of the main objective of this research; to develop a new concept that controls the non-value added logistical costs in the primary aluminium casthouse supply chain

    Aligning Skills in Personnel with the Lean System\u27s Requirements

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    The sustainability of lean systems for long term is a major concern across various organizations implementing lean manufacturing methods. This issue can be attributed to inadequate infrastructure, inefficient process management, unsuitable personnel management methods and strategic tools. There is a strong need for addressing the risks for lean system sustainability. The resolution of the risks from a \u27soft side\u27 (people) perspective has not been addressed. The primary focus of this study is on the people-related risks. The current study elicits a five-phase approach to enhance the implementation of the lean system by accounting for these risks. The first phase classifies the requirements of the lean system into six subsystems and proposes the precedence of lean activities within each subsystem. The second phase identifies the risks for the sustainability of the subsystems by categorizing these risks into Personnel, Material, Equipment and Schedule. The third phase uses expert opinions based on a survey to quantify risks. The fourth phase addresses the resolution of the people-related risks. The mapping of these risks with the required skills in personnel is proposed. A Lean Personnel Alignment Model (LPAM) is presented to align the identified skills with lean requirements in order to sustain lean implementation

    New polymer mortar formulations : development, characterization and application forms

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    Tese de Doutoramento. Doutoramento em Engenharia Mecânica. Universidade do Porto. Faculdade de Engenharia. 200

    Spray casting project final report

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    Mass Production Processes

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    It is always hard to set manufacturing systems to produce large quantities of standardized parts. Controlling these mass production lines needs deep knowledge, hard experience, and the required related tools as well. The use of modern methods and techniques to produce a large quantity of products within productive manufacturing processes provides improvements in manufacturing costs and product quality. In order to serve these purposes, this book aims to reflect on the advanced manufacturing systems of different alloys in production with related components and automation technologies. Additionally, it focuses on mass production processes designed according to Industry 4.0 considering different kinds of quality and improvement works in mass production systems for high productive and sustainable manufacturing. This book may be interesting to researchers, industrial employees, or any other partners who work for better quality manufacturing at any stage of the mass production processes

    National Educators' Workshop: Update 1993. Standard Experiments in Engineering Materials Science and Technology

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    This document contains a collection of experiments presented and demonstrated at the National Educators' Workshop: Update 93 held at the NASA Langley Research Center in Hampton, Virginia, on November 3-5, 1993. The experiments related to the nature and properties of engineering materials and provided information to assist in teaching about materials in the education community

    Novel indirect additive manufacturing for processing biomaterials

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    PhD ThesisThe aim of this work was to identify methods for the production of patient-specific biomedical devices via indirect additive manufacturing (AM) methods. Additive manufacturing has been shown to provide a good solution for the manufacture of patient specific implants, but in a limited range of materials, and at a relatively high cost. This research project considered what are known as “indirect” AM approaches, which typically consider AM in combination with one or more subsequent processes in order to produce a part, with a maxillofacial plate and mandible resection used as a demonstrator application. Three different approaches were considered: (i) using AM to produce moulds for powder pressing of bioceramic green parts for subsequent sintering; (ii) using AM to produce moulds for biopolymer sintering; and (iii) 3D printing of bioceramic powders into green parts for subsequent sintering. Apatite wollastonite glass ceramic (AW) and poly-Lactide-co-glycolide (PLGA) were selected as the bioceramic and biopolymer materials to process. These were characterised before and after processing in order to ensure that the processing route did not affect the material properties. Geometric dimensions, the morphological structure and mechanical properties were studied to establish the accuracy, shrinkage and strength of the fabricated biomaterial implants. The use of AM processes to produce moulds for PLGA sintering, and the 3D printing of bioceramic powders formed the best overall results in terms of the definition and properties of the manufactured parts. Parts produced were accurate to within 5% of the as designed dimensions for both the PLGA sintering and the bioceramic powders 3D printing. The indirect AM methods are considered to be promising processing routes for medical devices.University Malaysia Perlis and the Malaysian Higher Education Ministr
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