A Flexible Simulation Tool for Manufacturing-cell Design

We present a two-phase approach to design and analysis of manufacturing cells based on simulated experimentation and response surface methodology using a general manufacturing-cell simulation model. The first phase involves factor-screening simulation experiments to identify design and operational factors that have a significant effect on cell performance as measured by a comprehensive annual cost function. In the second phase of experimentation, we construct simulation (response surface) meta-models to describe the relationship between the significant cell design and operational factors (the controllable input parameters) and the resulting simulation-based estimate of expected annual cell cost (the output response). We use canonical and ridge analyses of the estimated response surface to estimate the levels of the quantitative input factors that minimize the cell's expected annual cost. We apply this methodology to an assembly cell for printed circuit boards. Compared to the current cell operating policy, the simulation metamodel-based estimate of the optimum operating policy is predicted to yield average annual savings of approximately $425 000, which is a 20% reduction in annual cost. In a companion paper, we detail the structure and operation of the manufacturing-cell simulation model.     

A Flexible Simulation Tool for Manufacturing-cell Design

We present a general manufacturing-cell simulation model for evaluating the effects of world-class manufacturing practices on expected cell performance. The modular structure of the simulation provides the flexibility to analyze a wide variety of manufacturing cells. We formulate a comprehensive annualized cost function for evaluation and comparison of alternative cell configurations. A case study involving assembly of printed circuit boards illustrates the potential benefits of using this tool for cell design and analysis. The simulation model is intended for use in a two-phase approach to cell design that is based on simulated experimentation and response surface analysis as detailed in a companion paper.     

一种动态识别瓶颈机床的前向启发算法

为了解决作业车间调度问题中的瓶颈漂移和动态识别问题,提出了一种动态识别瓶颈机床的前向启发算法.该算法引入搜索空间的概率分析方法,通过工序开工概率、工序对机床的独立需求概率、机床累计需求概率和3个量化参数,构造了以竞争高峰时段的机床负荷量大小为判定依据的瓶颈机床识别启发规则.实验结果表明该方法能够有效识别瓶颈机床,使得大规模作业车间调度的求解复杂度显著降低.     

机床涂装工艺浅述

我国现阶段机床产品的涂装工艺仍以小批量、手工为主,随着机床零部件质量的提高以及规模化生产,原有机床涂装方式已不适合现代机床工业的生产.通过对机床产品特性的分析和方案比较,提出了机床产品涂装工艺设计和平面布置,并介绍了主要的涂装设备:水旋喷漆室、油漆烘干室、多功能喷涂打磨室.通过对机床涂装工艺合理的设计,使得工件可以按产品特性组织批量生产.     

An Investigation of Vibration Reducing on a Machine Tool

In order to reduce the vibration on a machine tool, more orthogonal experiment schemes have been designed, which are based on the steel balls vibration reducing principle. After experiments the optimal reducing vibration scheme was determined. This kind of vibration reducing scheme is used in steel balls vibration absorber, which can be used to reduce vibration magnitudes of a machine tools under the working conditions, whereby improving machining precision. The suggested experiment method is of useful reference in reducing vibrations on other machine tools too.     

一类并联机床整机结构动力学建模方法研究

研究了一种外副驱动的3平动自由度并联机床整机结构动力学建模方法。该方法借助子结构综合思想，将整机结构划分为机架、连杆和动平台三个子结构，用有限元法分别构造各自的动力学方程，再利用变形协调条件得到考虑机架弹性的整机动力学模型。该方法可避免采用商用有限元软件必须针对不同位形重新划分网格的局限性，便于揭示结构参数对低阶模态的影响及其在整个工作空间内的变化规律，故为这类机构一结构耦合复杂时变系统的动刚度快速预估和动态设计奠定了坚实的理论基础。     

基于神经网络的Stewart型并联机床位置正解

以Stewart型并联机器人为例,由机器人的位置逆解问题引出机器人运动学正解问题。在分析BP网络特点基础上,利用位置逆解结果,通过训练样本的学习,确定神经网络权系数。实现操作手从并节变量空间到工作变量空间的非线性映射,能够准确地求解并联机器人的位置和姿态。结果表明,该方法效果良好。     

FMS在线刀具管理系统研究

提供了一种刀具管理软件框架结构，提出了刀具调度优化目标非线性规划数学模型，研究出一种工业衫性启 式在线刀具动态调度算法。     

一种新型雷管脚线自动打把机

介绍了一种集伺服驱动、气动及精密机械传动于一体的新型电雷管脚线自动打把机.该设备采用独特的"Z" 字形打把方式,通过PLC控制,在4 s的时间内连续、自动地完成20个不同的动作并打出2个把线,具有先进、高效、自动和可靠等特点, 是传统机械式打把机的更新换代产品.     

Flexible Gold Nanocone Array Surfaces as a Tool for Regulating Neuronal Behavior

Accelerated neurite outgrowth of rat cortical neurons on a flexible and inexpensive substrate functionalized with gold nanocone arrays is reported. The gold nanocone arrays are fabricated on Teflon films by a bottom‐up approach based on colloidal lithography followed by deposition of a thin gold layer. The geometry of nanocone arrays including height and pitch is controlled by the overall etching time and template polystyrene beads size. Fluorescence microscopy studies reveal high viability and significant morphological changes of the neurons on the structured surfaces. The elongation degree of neurite is maximized on the nanocone arrays created with 1 µm polystyrene beads by a factor of two with respect to the control. Furthermore, the interface between the neurons and the nanocones is investigated by scanning electron microscopy and focused ion beam cross‐sectioning. The detailed observation of the neuron/nanocone interfaces reveals the morphological similarity between the nanocone tips and the neuronal processes, the existence of interspace at the interface between the cell body and the nanocones, and neurite bridging among the neighboring structures, which may induce the acceleration of neurite outgrowth. The flexible gold nanocone arrays can be a good supporting substrate of neuron culture with noble electrical and optical properties.     

Real-time Operating System of a CNC Machine Tool

FOrwardComputernumericalcontrolisamorematurefieldintheareaofreal-timeconealofthecomputer.FromthestandPOintofsoftware,itisamonOProgramndngbatchProcessingreal-timeoperatingsystem.User'spartPro~(specifichigh-levellanguage)isprognrIUnedintheformofblock.O...     

大型非球曲面超精密复合加工机床

详细介绍了“大型非球曲面超精密复合加工机床”．该机床具有磨削、铣削、车削等多种加工功能,采用了高精度的FANUC系统,在X横向导轨上设计了独特的卸荷系统,在Z垂直导轨上设计了精确的配重系统,主轴转速为150r／min,可加工最大尺寸为φ1200mm的工件．用高精度的电感测微仪和自准直仪对机床进行了检测,结果表明：其数控系统位置及控制分辨率为0．05μm,主轴回转精度为26nm．最后,用该机床进行了超精密加工试验,经检测,其加工工件的表面粗糙度Ra优于15nm,实现了大型非球曲面的超精密加工．     

Minimizing the Weighted Sum of Late and Early Completion Penalties in a Single Machine

We consider the problem of scheduling n jobs on a single machine so as to minimize weighted absolute deviation of completion times from their due dates. The general problem is NP-complete, but we show how to solve a special case.     

浅谈机床夹具实验教学模型的设计

本文通过对目前机械设计专业教学中常用的机床夹具模型进行分析,指出了目前在前机床夹具实验教学模型的设计中经常遇到的问题,并提出了相应的改进方法,文章的最后还对提高机床夹具模型的设计能力浅谈了一些看法。     

机床的批量定制生产实施策略分析

通过分析机床产品的产品结构、生产过程和客户需求等特点，指出选择型定制是实现机床批量定制的主要类型；研究探讨了机床批量定制生产在产品设计制造技术、生产过程的组织及管理等方面的实施策略，提出了适应机床批量定制生产的ERP系统的组成结构体系。     

基于多功能加工平台的微细电解加工

电解加工在加工过程中因难以控制加工形状而很少应用在微细加工领域,为了对微细电解加工可行性进行探索,设计了多功能微细加工平台,利用多功能微细加工平台可为微细电解加工在线制作电极,采用低加工电压、低浓度的钝化电解液、高频窄脉冲电源和高速旋转的微细电极,进行了微细电解加工实验,取得了很好的工艺效果,加工间隙是影响加工精度的关键因素,设计了一个加工间隙控制伺服系统,以保证微小的加工间隙,在厚为100μm的不锈钢薄片上用微细电解打孔加工出直径为65μm的微小孔,利用微细电解加工时电极无损耗,提出采用简单圆柱微细电极进行微细电解铣削,加工出较高精度的微结构,取得了较好的工艺效果,从而验证了该微细电解加工装置的微细加工能力和方法的可行性。     

电火花加工机床主轴头振动测试

对国产电火花加工机床主轴头振动进行了测试，并与进口精密电火花加工机床主轴头的振动进行了比较，给出了多种振动波形。     

基于最优解下限的单工序平行机排序启发式算法

针对单工序平行机排序LPT方法计算步骤多等问题,提出了一种适用于中小企业现场排序的最优解下限截取启发式算法。传统平行机排序最优解下限表达式存在因偏离最优解过大而难以引导排序走向最优的缺陷,改进后的下限表达式更加接近于最优解。从计算步骤多少和偏离最优解下限的最大偏差率两个角度,比较分析了最优解下限截取法与LPT法的特点。经实验数据验证,得出零件数与平行机数之比非整除且满足一定条件时,简单易行的截取法更优于LPT法的结论。     

精密机床主轴轴承的预紧力控制

 以FL-1000型精密磨床主轴系统为对象,设计了一种精密机床主轴轴承预紧力实时控制系统.根据实际工况,确定该机床的最佳预紧力,对其控制原理和控制算法的设计进行了分析,并以FL-1000型精密磨床主轴系统为例验证了预紧力实时控制的可行性.