基于SLP和Witness的车间布局设计

针对车间布局设计中提出的提高生产效率、优化生产物流的要求,提出改进式车间布局设计方法。使用SLP方法对车间各作业单元进行划分,量化各作业单元之间的物流关系及非物流关系,通过设定重要性比例确定作业单元间综合相互关系,并得出车间布局方案群。通过设定Witness仿真参数,对初选方案生产物流运行状况进行动态模拟,通过车间物流量及路径拥塞率的对比得出方案优选结果。     

Production activity control: A practical approach to scheduling

There is a widely perceived gap within the domain of scheduling for manufacturing systems, namely, many of the methods employed by production supervisors are quite different from those developed by researchers. In a sense, this inconsistency highlights the important fact that much scheduling research has failed to win approval where it matters most, namely, within the manufacturing system.In this article, we argue for a practical approach to scheduling for manufacturing systems, one that we believe can narrow, and possibly bridge, the gap between theory and practice. This approach is based upon a well-defined and modular architecture for scheduling, termedproduction activity control. This architecture is the foundation of our proposed solution to scheduling, since it provides a coherent blueprint for the synthesis of information technology and scheduling strategies. The result of this synthesis is a design tool for production activity control, which allows for detailed and disciplined experimentation with a range of scheduling strategies in a controlled and simulated environment. Due to the unique modular property of the design tool, these strategies may then be implemented live in a flexible manufacturing facility, hence narrowing the gap between scheduling theory and manufacturing practice. Our overall approach is tested through an appropriate implementation in a modern electronics assembly plant.     

Cascading flowlines and layout modules: Practical strategies for machine duplication in facility layouts

The standard approach for design of a layout for a high-variety low-volume (HVLV) manufacturing facility has been to use either a from-to chart or a multi-product process chart to design a process layout or a cellular layout, respectively, for the facility. Considerable research has focused on making a go-no go decision to implement any one of these two traditional layouts as the preferred layout for an HVLV manufacturing facility. This paper introduces a variety of Hybrid Cellular Layouts (HCLs) which integrate the attributes of the traditional functional, cellular and flowline layouts. The mathematical models and methods for design of two HCLs—cascading flowline layout and modular layout—are discussed in detail. Unlike the standard models in the literature, the design of the cascading flowline layout introduces a novel string-to-graph aggregation and planar graph embedding method that allows machine duplication in the layout. Similarly, the design of the Modular layout introduces a substring clustering method instead of the standard method of cluster analysis to form part families using the complete routings of the parts. For each HCL, results from an industry project are presented to demonstrate the real-world viability of the concepts, methods and software developed to support the design of HCLs for high-variety low-volume manufacturing facilities.     

大庆油田有限责任公司井下砂酸选配厂物料布置设计分析

中油公司大庆分公司井下砂酸选配厂主要负责井下公司压裂用支撑剂和酸剂的生产销售工作,该厂年物料接收搬运量较大,费用约占厂内生产费用的三分之一。本文本着“物流管理是企业第三利润源泉”的思想,对该厂物料布置现状进行了认真分析,并建立了两个数学模型。依据数学模型的指导,提出了该厂新的物料布置构想,根据计算结果显示,新的物料布置方案可使物料接收和搬运成本降低33%,使厂内物流的总成本降低18.2%,从而有效地提高该厂的经营效益。     

An elitist strategy genetic algorithm for integrated layout design

While designing the layout of any manufacturing organizations, the primary objective is to decide an optimal arrangement of their departments (machines or cells) in a two-dimensional shop floor (facility) satisfying desired objectives, which is termed facility layout problem (FLP). In traditional layout design philosophy, the inter-cell layout and flow path layout design of material handling system (MHS) was carried out step by step in a sequential manner. This results in sub-optimal solutions for FLP. In this paper, an integrated approach is adopted to design the inter-cell layout and the flow path layout of MHS simultaneously. The quality of the final layout is evaluated by minimizing the weighted sum of two distance-based cost objectives namely, (1) total material handling cost. (2) Distance-weighted cost of total closeness rating score. Sequence-pair (SP) representation is used for layout encoding. The translation from SP to layout is efficiently done by longest common subsequence methodology. Due to NP-hard nature of the proposed problem, an elitist strategy genetic algorithm (ESGA) is developed and tested with three test problem instances available in the literature. It is found that the proposed ESGA algorithm is able to produce the best solutions consistently, twice faster than the standard GA for the test problem instances.     

An new approach for the automatic analysis and control of material handling systems: integrated layout flow analysis (ILFA)

In the majority of small and medium sized enterprises (SEMs), the direct costs of material handling cannot be clearly measured. There are several reasons for this, including the large number of product types, complexity of their production cycle, and continuous change in markets. Therefore, production managers require flexible tools to create a suitable material handling system model which explicitly and rapidly calculates the indices required as these are traditionally neglected or laboriously approximated, (i.e., time and cost in material flow inside the factory, storage area requirements, and MH utilization percentage). This paper proposes an integrated approach to analyzing and controlling material handling operations in an industrial manufacturing plant from a “full quantitative” point of view. The model presented unites quite different fields of research into a unique methodology. This material handling model rapidly and automatically provides production managers with extensive and significant information. As a result, integrated layout flow analysis interrelates systematic layout planning with operational research algorithms and visual interactive simulation, using a complete software platform to implement them. This integrated layout flow analysis approach focuses on determining the space requirement for manufacturing department buffers, the transportation system requirements, the performance indices, and the time and cost of material flows spent in the layout and in MH traffic jams.     

An elitist strategy genetic algorithm using simulated annealing algorithm as local search for facility layout design

A well-planned arrangement of manufacturing departments on a two-dimensional planar region considerably increases the efficiency of its production systems, which is termed facility layout problem (FLP). Conventional layout design approach often designs intercell layout (determining exact location of each department on shop floor area) and flow path layout design of material handling system (MHS) step by step in a sequential manner. This results in suboptimal solutions for FLP. In this paper, an integrated approach is adopted to design the intercell layout and the flow path layout of MHS simultaneously. The quality of the final layout is evaluated by minimizing total material handling cost. Sequence pair (SP) representation is used for layout encoding. The translation from SP to layout is efficiently made by longest common subsequence (LCS) methodology. An elitist strategy genetic algorithm using simulated annealing (E-GASAA) as a local search mechanism is developed and tested with four test problem instances available in the literature. Elitist strategy is incorporated to enhance convergence characteristic of the proposed algorithm. It is found that the proposed E-GASAA is able to produce best solutions consistently for the test problem instance of different sizes within acceptable computational effort. In addition to that, we tried to reduce the computational load with the help of adopted LCS computation methodology and achieved a good improvement.     

Automatic discontinuous 2 transmission lines with sections of different productivity (<Emphasis Type="Italic">q</Emphasis><Subscript>1</Subscript> < <Emphasis Type="Italic">q</Emphasis><Subscript>2</Subscript>)

An analytical solution is derived for automatic discontinuous 2s’ transmission lines with sections of different productivity (q ₁ < q ₂). On that basis, a range of characteristics that depend on the reliability of the production sections and the bunker capacity may be determined. Accordingly, the solution provides the basis for improvements in the design of such lines.     

Application of a Layout/Material Handling Design Method to a Furnace Area in a 300 mm Wafer Fab

For many years, material handling within the semiconductor industry has become increasingly important. With the introduction of 300 mm wafer production, ergonomics and product safety become more critical. Therefore, the manufacturers of semiconductor wafer fabs are considering the automation of intrabay material handling. In this paper, a routine and efficient design method consisting of two parallel iterative procedures is proposed to overcome the complexity and the amount of time required for material handling design. Since material handling is a non-productive item supporting the value-adding manufacturing activities, it should be minimised. This is realised by the rearrangement of the manufacturing activities, referred to as layout design. Both the layout and material handling design methods are applied to a case study concerning the furnace area of a semiconductor wafer fab.     

The Application of Chip Removal and Frictional Contact Analysis for Workpiece–Fixture Layout Verification

In this paper, a workpiece–fixture layout verification approach with the application of frictional contact and chip removal effects using a finite-element technique, is presented. The objective of the proposed system is to overcome the deficiencies of existing fixture design approaches. Workpiece–fixture layout verification analysis is carried out for time varying machining forces to ensure that the workpiece will be held against the cutting and clamping forces. The chip removal effect and frictional contact between the workpiece and the fixture elements are taken into account using a material removal approach based on element death technique and nonlinear finite-element analysis. A case study illustrates the application of the proposed approach. ID="A1"Correspondance and offprint requests to: Professor F. ?ztürk, Department of Mechanical Engineering, Mühendislik-Mimarlik Fakültesi, G?r¨kle Kampusu, Bursa 16059, Turkey. E-mail: ferruh@uladag.edu.tr     

Antiproliferative and genotoxic effects of <i>Mikania glomerata</i> (Asteraceae)

Mikania glomerata is a plant used in Brazilian traditional medicine, known as ‘guaco’. It possesses anti-inflammatory properties and the aqueous extracts of its leaves are indicated for the treatment of diseases of the respiratory tract. This study aimed at evaluating the antiproliferative and genotoxic effect of Mikania glomerata leaf infusions on the cell cycle of onion. The material used was collected in the native environment from Rio Grande do Sul State, Brazil. Aqueous extracts through infusions were prepared in two concentrations: 4g/L (usual concentration) and 16g/L (4x more concentrated) of each of the populations. Two groups of four onion bulbs for each plant population were used plus a control group. The rootlets were fixed in ethanol-acetic acid (3:1), conserved in ethanol 70% and slides were prepared using the squashing technique colored with orcein 2%. The cells were observed and analyzed during cell cycle. Per group of bulbs, 2000 cells were analyzed, and the mean values of the cell number of each of the phases of the cell cycle were calculated, determining the mitotic index (MI). Statistic analyses of the data were carried out by the x2 (p= 0.05) test. We conclude that M. glomerata presents both antiproliferative and genotoxic activity.     

<Emphasis Type="Italic">Rapid Moulding Using Epoxy Tooling Resin</Emphasis>

Rapid prototyping (RP) is fast becoming a standard tool in today’s product design and manufacturing environment. Significant benefits in terms of lead time and cost savings have been reported with the use of RP technology. However, these benefits can be derived only during the design and planning stages of a new product where RP parts are produced in small quantities for design evaluation, form fitting, and marketing analysis. The high cost of raw material stock used in current RP systems makes them economically unsuitable even for small-batch production during the product evaluation and manufacturing stages. Further to this, the difference between the mechanical and physical properties of RP and traditional manufacturing materials limits the functionality of RP end products. Rapid tooling (RT) technology has opened up new cost-effective solutions for small-batch production. In this paper, a technique using a rapid soft-tooling approach, namely, aluminium filled epoxy resin tooling for injection mould preparation is successfully explored. An aluminium filled epoxy resin mould is evaluated and the characteristics of the injection-moulded end products are presented.     

联合厂房的工艺布局设计

简要介绍了工业联合厂房的工艺布局要求。联合厂房的工艺布局应根据企业规划的生产纲领,遵循物流最优化等原则,结合联合厂房的面积及基础设施等建筑要求,在优化并整合各产品工艺流程的基础上,确定最短并完整的工艺路线,布放现有的工艺设备及其辅助设施和辅助区域。同时,为保证随着生产的发展,工艺布局设计能与联合厂房内部便于灵活调整的特点相适应,布局设计中应预留出发展的空间,用于布放新增生产设备及其辅助区域。     

汽车车身焊装机器人工作站设计及应用

分析了机器人在目前车身焊装中的应用情况,以车身主焊线中应用的机器人工作站为例,进行了详细的布局设计、工艺设计、控制设计、安全设计和电器实现设计。文中所述的设计方案可实现白车身的批量生产功能,并可与现场MES系统集成为生产指示,具有一定的实用性和参考价值。     

Micropropagation of <i>Prosopis chilensis</i> (Mol.) Stuntz from young and mature plants

Prosopis chilensis (Mol.) Stuntz (Algarrobo de Chile) is an important native tree species that can be grown in arid and semiarid regions for wood and forage production and environmental protection. Developing a simple and reliable in vitro protocol for cloning it would enable to improve it genetically. Explants of P.chilensis were taken from 4 months-old plants grown in the greenhouse or from adult trees grown in a natural environment. Nodal segments 1 – 2 cm long containing an axillary bud were selected from elongating shoots. These cuttings were aseptically cultured on two agar-solid basal media, MS or BTMm, and treated with 0.05 mg L^-1 BA and 3 mg L^-1 of either IAA, IBA or NAA. Sucrose (3% w/v) was used as carbon source. The percentage of sprouted cuttings and whole plant regeneration as well as its shoot and root length were recorded. Number, length and dry weight of shoots and roots were also measured. Rooting was successful with cuttings taken from young or adult plants, but explants from young plants showed a better response. Culturing in BTMm resulted in significantly greater shoot and root biomass than culturing in MS. Moreover, this response was higher in young explants when IBA was used as growth regulator. This paper reports a simple and effective method to micropropagate P. chilensis from young and adult plants.     

A simulation-based approach for risk assessment of facility layout designs under stochastic product demands

In traditional facility layout design method, the facility layout is governed by the flow intensity between departments, which is the product flow quantity between departments. A facility layout design must maintain its efficiency over time while coping with the uncertainty in product demand. An error in the product demand assessment can render the layout inefficient with respect to material handling costs. Analytical models for the determination of the risk involved in a facility layout design are difficult to derive when the problem of size and complexity increases. This paper presents a simulation-based method for predicting the uncertainty associated with the layout. The validation of the simulation approach against analytical procedures is first detailed. The methodology for the simulation based approach is provided. Three scenarios of increasing complexity and size are also detailed. Results from case studies have shown that the procedure results in reduction of risk as high as 80%.     

A fuzzy DEMATEL-based solution approach for facility layout problem: a case study

Facility layout in production systems is a difficult activity since both qualitative and quantitative factors affect the location decision, and also influence and causal relationship between these factors should be determined for a better location. In this respect, it is demonstrated in this study that fuzzy decision-making trial and evaluation laboratory (fuzzy DEMATEL) method can effectively be used in handling facility layout problems in practice. The qualitative factors that described by linguistic terms can be taken into account through fuzzy structure of the method. Considering this, a fuzzy DEMATEL-based solution approach for facility layout problem is proposed in this study. The proposed approach takes into account both qualitative and quantitative location factors. To address the need in practice, six important location factors are considered in this study. These are material flow, information flow, personnel flow, equipment flow, environmental condition, and supervision of personnel. This study differs from the previous works in that it applies fuzzy DEMATEL method to facility layout problem. To explore the viability of the proposed approach, a real world problem in a machinery industry firm is handled.     

A hybrid approach to the development of a multilayer neural network for wear and fatigue prediction in metal forming

In this paper an approach to surface damage prediction is proposed for the case of metal forming. The method is mainly based on three fundamental stages: (a) the detection of a feasible physical model which is able to give some important understanding of the phenomenon, although with limited generality; (b) the extensive development of an organized experimental campaign, which is necessary to tune up the developed model; and (c) the organization of an efficient and intelligent way of data collecting. The three aspects of the research work have been integrated by means of a neural network which is trained by using data coming from the real plant, from the standard tribometers, and from the reference numerical model. In this sense, the neural network is indented as hybridized. Predictions are shown to be very close to the experimental data obtained in the production plant. The method is useful for minimizing the number of experiments in the process of materials and treatment selection, and in maintenance.     

Development of a Practical Blank Layout Optimisation System for Stamping Die Design

Blank layout is one of the most important processes in stamping die design. As the major cost in sheet metal stamping is the material cost, any efforts to minimise the scrap may result in substantial savings not only in strip material, but also in overall production. This paper is mainly targeted at establishing a practical blank layout optimisation system for stamp ing die by using AutoCAD’s ObjectARX toolkit. The basic principles of blank layout optimisation are first described, and then the general structure of the system is proposed. Not only a suitable algorithm for layout calculation, but also the manufacturing requirements and user operation are fully considered in this system. Finally, an algorithm for blank shape offsetting is proposed to solve the problem of self-intersection in offset curves, and the traditional ‘1-step tranzlation’ algorithm for the calculation of layout parameters is improved to eliminate the conflict between precision and efficiency in the layout optimisation.     

Expression analysis of <i>OsSERK</i>, <i>OsLEC1</i> and <i>OsWOX4</i> genes in rice (<i>Oryza</i> sativa L.) callus during somatic embryo development

Somatic embryogenesis is an asexual reproduction process that occurs in many plant species, including rice. This process contains several totipotency markers such as Somatic Embryogenesis Receptor-like Kinase (SERK), Leafy Cotyledon1 (LEC1) and WUSCHEL-Related Homeobox4 (WOX4) and also a helpful model for embryo development and clones and transformations. Here, we report the gene expression during somatic embryo development correlates with regeneration frequency in 14 Javanica rice (pigmented and non-pigmented) using modifified N6 media supplemented with Kinetin (2.0 mg/L) and NAA (1.0 mg/L). Although there have been advances in understanding the genetic basis of somatic embryogenesis in other varieties, rice is still unexplored, especially during somatic embryo development. Moreover, for the formation of callus induction from immature embryos, 2,4-D (2.0 mg/L, 3.0 mg/L) was used. This study analysed the gene expression of OsSERK, OsWOX4 and OsLEC1 genes through RT-PCR analysis. Higher expression of the OsLEC1 gene indicates that their function may correlate in the in vitro with the high response of rice after transfer to regeneration media. This study found that rice varieties of pigmented rice (MS Pendek and Gogoniti II) and non-pigmented rice (Pandan Ungu) showed high regeneration frequency, showing higher OsLEC1 expression than other varieties because OsLEC1 promotes the maturation of somatic embryos in plant regeneration on day 14. However, the contrast with Genjah nganjuk may be effective because of other regulatory genes. RT-PCR analysis showed OsSERK had less expression level than OsLEC1 and OsWOX4 in the varieties, which correlate with the percentage of plant regeneration, but not for Gogoniti II. In conclusion, the higher percentage of plant regeneration correlates with the higher expression level of OsLEC1 at day 14 of media regeneration of rice.