Runout effects in milling: Surface finish, surface location error, and stability

This paper investigates the effect of milling cutter teeth runout on surface topography, surface location error, and stability in end milling. Runout remains an important issue in machining because commercially-available cutter bodies often exhibit significant variation in the teeth/insert radial locations; therefore, the chip load on the individual cutting teeth varies periodically. This varying chip load influences the machining process and can lead to premature failure of the cutting edges. The effect of runout on cutting force and surface finish for proportional and non-proportional tooth spacing is isolated here by completing experiments on a precision milling machine with 0.1 μm positioning repeatability and 0.02 μm spindle error motion. Experimental tests are completed with different amounts of radial runout and the results are compared with a comprehensive time-domain simulation. After verification, the simulation is used to explore the relationships between runout, surface finish, stability, and surface location error. A new instability that occurs when harmonics of the runout frequency coincide with the dominant system natural frequency is identified.     

Effects of flow, brass location, tube materials and temperature on corrosion of brass plumbing devices

Effects of plumbing-specific installation factors on brass corrosion were investigated in a series of pipe-loop experiments. Increased flow velocity increased corrosion rates, but did not affect corrosion type. The presence of copper tubing in the plumbing system increased selectivity of brass corrosion for zinc, unless a galvanic connection was made between copper and brass, in which case corrosion became more uniform and was accelerated. Plastic tubing allowed oxidant (i.e., free chlorine) to persist in water, increasing brass exposure. Additionally, hot water significantly increased lead leaching from brass. These findings may inform future investigations into brass corrosion issues and plumbing designs.     

An array waveguide probe for detection,location and sizing of surface cracks in metals

The paper describes the development of a novel microwave probe for detection, location and sizing of surface cracks in metals. The probe utilizes the inherent mutual coupling in an array structure to determine crack alignment, placement and dimensions. The main feature of the probe is its ability to electronically scan the region of concern, thus avoiding the large inspection time and unwanted noise experienced in the conventional mechanical scanning. Theoretical and experimental results are presented for a prototype two-cell array probe when scanning a metallic specimen containing a long surface crack. It is shown that the probe is capable of determining the orientation, location and dimensions of surface cracks of a few millimeters depth.     

基于Moldflow的注射模浇口位置优化

针对浇口位置直接影响聚合物分子的取向和塑件成型的翘曲变形问题,运用Moldflow软件对塑件不同浇口位置的填充时间、熔接痕、气穴分布、注射压力及锁模力进行分析比较,得到了浇口位置的优化方案,从而有效降低了生产成本,缩短了产品开发周期,提高了模具设计效率。     

Closed-form solutions for surface location error in milling

This paper provides two new analytical solutions for the computation of surface location errors, or part geometry errors that arise due to forced vibrations of the cutting tool, during stable milling. Prior studies of surface location error have applied numerical simulation and semi-analytical methods (e.g., temporal finite element analysis) to this problem. This work provides new results that show analytical solutions for the problem of surface location error are possible. The analytical approaches are based on frequency domain and harmonic balance analyses. Comparisons between the analytical results, time domain simulation, and experiment are included.     

Improved workpiece location accuracy through fixture layout optimization

Inaccuracies in workpiece location lead to errors in position and orientation of a machined feature on the workpiece. The ability to accurately locate a workpiece in a machining fixture is strongly influenced by rigid body displacements of the workpiece caused by elastic deformation of loaded fixture–workpiece contacts. This paper presents a model for improving workpiece location accuracy in fixturing. A discrete elastic contact model is used to represent each fixture–workpiece contact. Reduction in workpiece locating error due to rigid body displacements is achieved through optimal placement of locators and clamps around the workpiece. The layout optimization model is also shown to improve the overall workpiece deflection and reaction force characteristics.     

Acoustic emission source location on a cylindrical surface

Acoustic emission (AE) is a stress wave, generated in a structural material when it is stimulated by perturbations. One of the important features of this technique is to detect the location of the AE source in the structure from the differences in the times of arrival of stress waves at several sensors placed on it. A generalized mathematical formalism for the evaluation of the path travelled by an acoustic wave on the surface of a structure, on the concept of geodesics, is presented. Based on this concept, a mathematical method is developed for the calculation of the coordinates of an AE source on a cylindrical surface by three AE sensors. This concept has not been attempted analytically so far, to our knowledge.     

A framework for international location decisions for manufacturing firms

The purpose of this paper is to address current shortcomings in international location decisions (ILD), which were identified through an exploratory study, by developing a model that addresses previous limitations in research and encapsulate an adequate theories and frameworks. Based on insights from an exploratory study on 17 Danish manufacturing firms and a literature review of over a 100 publications, the scope model was developed with the MECE principles in mind in order to encompass all aspects as identified, while being supplemented by adequate tools and models in different phases of the ILD process. This paper presents an application-oriented model for facilitating ILDs in manufacturing firms, which is unique in its way of being exhaustive and yet able to decompose the ILD problem in different aspects and abstraction levels to assist firms in balancing and aligning their efforts with strategic goals and organizational values.     

基于CAE技术的盖板浇口位置优化

浇口位置在注塑模具设计中非常重要。基于MPI的gate location模块对盖板的浇口位置进行优化设计。以注射压力为优化目标,以浇口位置为变量,以CAE的方法来求解最优的浇口位置。将优化方案和初始设计方案进行了比较。结果表明优化方案优于初始设计方案,注射压力、锁模力、变形量等都比初始设计方案低。     

加工盘套类零件等分孔的双圆柱定位钻模

文章介绍了一种加工盘套类零件等分孔的双圆柱定位钻模,给出了其定位误差的计算公式.该钻模具有结构简单、操作方便、制造及装配工艺性好等优点.     

基于HHT的复合板非接触冲击损伤定位研究

航空/航天器、汽车、轮船等工程设施在服役过程中受到其他物体的冲击时,造成的损伤会引起构件的失效甚至会造成灾难性事故,如何采取有效的措施监测和评定这类活性冲击损伤至关重要.为了实现实时、准确地定位工程结构中的冲击损伤,提出了一种基于扫描式激光多普勒测振仪(SLDV)的非接触式冲击损伤定位方法.将希尔伯特黄变换(Hilbe...     

非对称多型腔模浇口位置优化设计

在对塑件质量进行分析的基础上,建立了注射模浇口位置的优化模型,利用CAE软件进行模拟,获取训练样本,用Matlab语言编制了应用程序,运用参数优化系统对非对称多型腔结构的浇口位置进行了优化,并给出了实例,可供设计参考。     

3Cr13侧定位钉的高效数控加工

根据3Cr13侧定位钉零件的设计要求,制定了合理的加工工艺,介绍了零件的数控编程技巧和数控加工中装夹、对刀、首件试切、工件更换、磨损补偿技巧等,找出模具零件在数控车床上的高效加工方法,提高生产效率。     

PLC技术在工作台定位改造中的应用

本文通过平面磨床改造实例,介绍了PLC技术在设备工作台定位改造中的应用,阐述了改造的基本方案和设计思路。     

Knowledge-based visual part identification and location in a robot workcell

This paper presents a method for identifying and precisely locating parts visible in the workspace of a robot workcell through analysis of single or multiple perspective images. Automatic integration of any number of arbitrary viewpoints permits detection of objects occluded from certain views, as well as providing varying image resolution and wider coverage of the visible workspace. Analysis is possible in the presence of image noise such as glare or shadow from poor lighting conditions, or structural errors such as missing or obscured object features. Automated visual detection of camera locations avoids precise camera positioning or setup time and permits use of a movable or roving camera. The system is capable of processing multiple camera input in a few seconds on a SUN 3/160 workstation, without the use of additional image processing hardware and can be easily ported to various computer systems.     

拱泥机器人定位系统研究

拱泥机器人是一种在水下泥土中按规划轨迹运动的水下特种机器人，用于替代目前沉船打捞中潜水员攻打千斤洞的手工作业。精确且可靠的定位系统是拱泥机器人研究中的一项关键技术。本文通过对机器人的结构与运动过程分析，设计了拱泥机器人的定位系统。利用卡尔曼滤波对机器人冗余的位置信息进行数据融合，数据融合算法的仿真结果表明该方法能有效地提高定位精度，同时提高了定位系统的可靠性。     

税控收银机外壳的浇口位置优化

应用MPI软件对税控收银机外壳制品的浇口位置进行优化设计。基于CAE模拟,分析了塑料制品浇口位置对制品质量的影响,并通过经验的定性分析与CAE软件的定量模拟结合,实现了浇口位置的优化。     

Chatter vibration and surface location error prediction for helical end mills

This paper describes a new theoretical model for the cutting forces of a helical end mill. A specific advantage for the presented model is the convenience in implementing the developed expressions for vibration prediction. Specifically, the presented force model is used to predict cutting forces with a Fourier series expansion, to predict surface location error with a Harmonic Balance approach, and to simultaneously predict surface location error and chatter vibration with an updated temporal finite element analysis. The developed analyses are compared and validated through comparisons with prior works.     

菱形销在砂箱模板中定位设计工艺分析

通过分析砂箱模板中的定位结构原理，阐述了我国大多数中小型企业普遍采用一面两孔定位中最常用的，以两个圆柱销及平面支承实现定位，以一圆柱销一削边销(长圆形销)和平面支承定位在砂箱模板中定位的优缺点，重点论述了采用以一圆柱销、一菱形销(砂箱全部采用圆套)和平面支承实现砂箱与模板的定位，易于作到工艺过程中的基准统一，保证砂箱(上、下)及模板的位置精度和重复精度，克服了砂箱在造型过程中不被卡死和砂箱椭圆套在加工制作时工艺复杂、周期长、成本高等缺点。