A computer-aided inspection planning system for on-machine measurement — part I: Global inspection planning —

Computer-Aided Inspection Planning (CAIP) is the integration bridge between CAD/CAM and Computer Aided Inspection (CAI). A CAIP system for On-Machine Measurement (OMM) is proposed to inspect the complicated mechanical parts efficiently during machining or after machining. The inspection planning consists of Global Inspection Planning (GIP) and Local Inspection Planning (LIP). In the GIP, the system creates the optimal inspection sequence of the features in a part by analyzing the various feature information such as the relationship of the features, Probe Approach Directions (PAD), etc. Feature groups are formed for effective planning, and special feature groups are determined for sequencing. The integrated process and inspection plan is generated based on the sequences of the feature groups and the features in a feature group. A series of heuristic rules are developed to accomplish it. In the LIP of Part II, the system generates inspection parameters. The integrated inspection planning is able to determine optimum manufacturing sequence for inspection and machining processes. Finally, the results are simulated and analyzed to verify the effectiveness of the proposed CAIP.     

AIWIN—a fast and jigless inspection technique for machined parts

Precision inspection of manufactured components having multiple complex surfaces and variable tolerance definition is an involved, complex and time-consuming function. In routine practice, a jig is used to present the part in a known reference frame to carry out the inspection process. Jigs involve both time and cost in their development, manufacture and use. This paper describes ‘as is where is inspection’ (AIWIN), a new automated inspection technique that accelerates the inspection process by carrying out a fast registration procedure and establishing a quick correspondence between the part to inspect and its CAD geometry. The main challenge in doing away with a jig is that the inspection reference frame could be far removed from the CAD frame. Traditional techniques based on iterative closest point (ICP) or Newton methods require either a large number of iterations for convergence or fail in such a situation. A two-step coarse registration process is proposed to provide a good initial guess for a modified ICP algorithm developed earlier (Ravishankar et al., Int J Adv Manuf Technol 46(1–4):227–236, 2010). The first step uses a calibrated sphere for local hard registration and fixing the translation error. This transformation locates the centre for the sphere in the CAD frame. In the second step, the inverse transformation (involving pure rotation about multiple axes) required to align the inspection points measured on the manufactured part with the CAD point dataset of the model is determined and enforced. This completes the coarse registration enabling fast convergence of the modified ICP algorithm. The new technique has been implemented on complex freeform machined components and the inspection results clearly show that the process is precise and reliable with rapid convergence.     

Dynamic performance of a cable with an inspection robot — analysis, simulation, and experiments

A special cable inspection robot is designed to inspect automatically the cables of a cable-stayed bridge. The free vibration equation of the cable-robot system is derived firstly to study the dynamic characteristics and safety performance of the system. Then, the effect of the robot on the cable natural frequency is discussed, and the dynamic response equation when a robot is climbing at a constant speed is deduced. Furthermore, the effect of the cable vibration on the robot’s climbing ability is studied. The natural frequency characteristics of the robot are analyzed and optimized to avoid the resonance between the cable and the robot, using a finite element model. Additionally, dynamic cable responses are simulated under different conditions wherein the robot mass are 10 and 200 kg, and the speeds are 0.2 and 0.3 m/s, respectively. At last, to demonstrate further the dynamic characteristics of the cable-robot system experimentally, cables are set up on the Junshan highway bridge over the Yangtze river. Similar experimental models of these cables are constructed, and vibration experiments are conducted to validate the theoretical calculation. The results show that a light robot has little effects on the cable vibration amplitude and vibration acceleration; this confirms the safety of the cable.     

Nonrigid parts’ specification and inspection methods: notions, challenges, and recent advancements

In a free state, nonrigid parts can take on different shapes compared to their design model. Such behavior of nonrigid parts introduces particular challenges to engineers during the geometric and dimensional requirements specification and inspection steps. Given that the choice of inspection method is guided by the requirement specification type, this paper presents two sections dealing, respectively, with the specification and the inspection method used for nonrigid parts. Accordingly, this paper proposes a categorization of the particular specification methods used for the geometric dimensioning and tolerancing of nonrigid parts under the American Society of Mechanical Engineers and International Organization for Standardization standards, as well as a review of the available approaches for the fixtureless inspection method of these parts. Typical applications of each specification method, as well as the advantages and drawbacks of their use, are proposed as general guidance. Finally, the current research trends into the fixtureless inspection methods of nonrigid parts are underscored.     

The modified firefly algorithm considering fireflies’ visual range and its application in assembly sequences planning

This paper proposes a modified discrete firefly algorithm (MDFA) to solve the problem of assembly sequence planning. Firstly, to improve the performance of the firefly algorithm (FA), we proposed a MDFA by endowing the fireflies with the capability of changeable visual range. The computing case shows the proposed algorithm is more effective and robust than standard FA, genetic algorithm and particle swarm optimization algorithm. Secondly, a method of how to set parameters for FA and MDFA is proposed. This method is practical in the application of FA to solve discrete problem. Thirdly, to make the sequences more closer to real industrial requirements, a so called process precedence relations (PPR) evaluation function is presented, which not only considering the interference between parts, assembly tools and clamps, but also regarding the assembly order between parts and their reference parts. Finally, the evolution performance of the MDFA is investigated, and the performance of the proposed approach to solve ASP is verified through two cases study.     

Disassembly sequence planning approach for product virtual maintenance based on improved max–min ant system

In order to realize automation and intelligence of product disassembly process in a virtual maintenance environment, an improved max–min ant system based methodology for product disassembly sequence planning was proposed. The feasibility graph for product disassembly process was defined and the mathematic model of product disassembly sequence planning problem was set up. Thus, the problem of product disassembly sequence planning was transformed into the problem of searching optimal path on a feasibility graph. Moreover, an improved max–min ant system based on the strategy of sorting elite ants was presented and the flowchart of the improved algorithm was designed. Finally, by simulation examples, the robustness and outperforming others of the improved algorithm were verified.     

2—苯基—3—烷基—7—硝基—1,4—氧硫杂萘—4,4—二氧化物的质谱研究

本文研究了新合成的八种２－苯基－３－烷基－７－硝基－１,４－氧硫杂萘－４,４－二氧化物的电子轰击质谱,对裂解规律进行了探讨     

Nautilus——鹦鹉螺

第一次接触Nautilus，比第一次听到发烧级音响还要吃惊。竟然有如此的喇叭，也竟然会有如此出色的效果!B＆W不是世界上最贵的喇叭，但绝对是世界上最物超所值的喇叭之一。     

暗夜精灵——Luminox

夜，死一样的静。柴油味夹杂着淡淡的水草，腐臭弥散在空气中。巡逻的炮艇慢慢地在河面游弋，甲板上的两个士兵慵懒的闲聊，突然，岸边的芦苇丛中闪出一道亮光，小艇顿时变成了一团火球。     

Material bead deposition with 2 + 2 ½ multi-axis machining process planning strategies with virtual verification for extruded geometry

Process planning for hybrid manufacturing, where additive operations can be interlaced with machining operations, is in its infancy. New plastic- and metal-based hybrid manufacturing systems are being developed that integrate both additive manufacturing (AM) and subtractive (machining) operations. This introduces new process planning challenges. The focus of this research is to explore process planning solution approaches when using a hybrid manufacturing approach. Concepts such as localized AM build ups, adding stock to a CAD model or section for subsequent removal, and machining an AM stock model are investigated and illustrated using virtual simulations. A case study using a hybrid laser cladding process is used to demonstrate the opportunities associated with a hybrid solution. However, unlike machining, the process characteristics from system to system vary greatly. These are portrayed via a high power, high material deposition feed rate laser cladding system. There are unique challenges associated with AM processes and hybrid manufacturing. New tools and design rules need to be developed for this manufacturing solution to reach its potential.     

H——TMG——75（S）燃烧器设计

燃烧器是工业炉上最主要的部件之一,是燃料的直接换能设备,其燃烧性能直接影响炉子的节能效果和被加热件的加热质量。针对我公司目前使用的烧咀性能较低,我们设计了H—TMG—75(S)型煤气烧咀。点火     

YLK——480、YOT——400液力偶合器鉴定会

机械工业部通用基础件局于1982年10月11日至13日在上海主持召开了液力偶合器产品鉴定会。到会的有机械工业部、冶金部所属钢厂、设计院和上海市经委、冶金局等33个单位,共55名代表。 代表们听取了起重运输机械研究所作的YLK-480,YOT-400调速型液力偶合器研制报告、工艺总结、高强度铝合金研究报告和上钢一厂、三厂、马钢厂等所作的转炉风机应用液力偶合器的使用报告,并审阅了有关技术     

RE—Ni—W—P—SiC—PTFE复合镀层的抗氧化性研究

研究了RE－Ni-W-P-SiC-PTFE复合镀层的抗氧化性。结果表明：RE－Ni-W-P-SiC-PTFE复合镀层随着氧化温度的升高,氧化膜的重量增加,但在800℃以下氧化温度对镀层的增重不显著;800℃以上,镀层的增重迅速增加,通过对三种镀层抗氧化性能的比较可知,RE－Ni-W-P-SiC-PTFE镀层的抗氧化性不如Ni-W-P,Ni-W-P-SiC及RE－Ni-W-P-SiC三种镀层好。     

1,1—二氯—2—乙氧基—2—芳基烯烃质谱开裂机理探讨

本文报道通过亚稳离子和精确质量测定,讨论了1,1—二氯—2—乙氧基—2—芳基烯烃的质谱裂解规律。提出了主要是经过McLafferty重排,再经过1,3—氢迁移的机理。     

TCS——柔性控制系统

80年代,种类繁多的集散控制系统(Distribute Control System)和可编程控制器(PLC)的出现,使自动化的可靠性和实时性,可操作性和可维护性都得到极大的改善,成为控制系统的主流产品。但由于各个厂家的产品都属于专用的系统,有各自的总线和通信标准及系列产品,编程软件和运行支持软件开放     

GPS——全球定位系统简介

<正> 全球定位系统(GPS)是美国国防部使用的卫星定位系统,由24颗卫星发送位置信息,如经度、纬度、高度、时间等,在地球上任何位置都可以收到8颗卫星的信号,接收机采用几何和三角原理,先与一颗卫星锁定,该卫星再与其他两颗卫星锁定,根据三角定位原理即获得准确位置。卫星信号有一组精确码,保证位置信号优于     

07——特种脂

07-特种脂是我厂为武钢进口一米七轧机研制的一种锂基润滑脂新产品。它是根据国外BRG-G-Li2号和G脂的规格进行试验的,除了具有良好的抗水性、耐温性、胶体安定性外,在机械安定性上由于武钢的特殊要求,指标上具有优于国外同类脂的特点,其10万次剪切差值在30个单位以下。它将取代同类进口脂,在冶金工业、汽车制造工业、矿山机电以及其它机械、电机工业中发挥作用。     

T—MAX U——强力型钻头

<正> 瑞典山德维克公司新近研制成功一种强力钻头和套料钻,简介如下: (1) 强力型T—MAX U短钻头这种短形强力钻头,具有极高的刚性。加工孔径为17.5～25毫米,这种刚性是由于排屑槽的特殊设计而获得的。钻头底部由大的R与抗弯强度较高的锥柄组成,专用于加工深度为直径1.5倍的孔。导套的夹头与钻头沟槽重合夹紧,这样可在更换刀具时保持固定的位置,并可稳定地传递扭矩。另外,这种新型钻头有4个供油孔,因此可有效地进行冷却;为了使切屑顺利排出,可向切削刃附近供给充分的切