Measurement of tool internal temperatures in the tool–chip contact region by embedded micro thin film thermocouples

Sensors capable of providing fast and reliable feedback signals for monitoring and control of existing and emerging machining processes are an important research topic, that has quickly gained academic and industrial interest in recent years. Generally, high-precision machining processes are very sensitive to variation in local machining conditions at the tool–workpiece interface and lack a thorough understanding of fundamental thermomechanical phenomena. Existing sensors to monitor the machining conditions are not suitable for robust in-process control as they are either destructively embedded and/or do not possess the necessary spatial and temporal resolution to monitor local tool internal temperatures during machining at the cutting tip/edge effectively. This paper presents a novel approach for assessing transient tool internal temperature fields in the close vicinity of less than 300 μm of the tool cutting edge. A revised array layout of 10 micro thin film micro thermocouples, fabricated using adapted semiconductor microfabrication methods, has been embedded into polycrystalline cubic boron nitride (PCBN) cutting inserts by means of a modified diffusion bonding technique. Scanning electron microscopy was used to examine material interactions at the bonding interface and to determine optimal bonding parameters. Sensor performance was statically and dynamically characterized. They show good linearity, sensitivity and very fast response time. Initial machining tests on aluminum alloys are described herein. The tests have been performed to demonstrate the functionality and reliability of tool embedded thin film sensors, and are part of a feasibility study with the ultimate goal of applying the instrumented insert in hard machining operations. The microsensor array was used for the acquisition of tool internal temperature profiles very close to the cutting tip. The influence of varying cutting parameters on transient tool internal temperature profiles was measured and discussed. With further study, the described instrumented cutting inserts could provide more valuable insight into the process physics and could improve various aspects of machining processes, e.g. reliability, tool life, and workpiece quality.     

石油输送多功能无线数据监控系统开发与应用

采用嵌入式操作系统,应用温压一体式传感器,结合无线网络,能及时发现油田油井生产管线上打孔盗油、凿眼破坏和管线穿孔等情况,实现线路巡查不需专人值守。根据温度、压力等数据的变化分析判断油井的生产情况。     

Insertable thin film thermocouples for in situ transient temperature monitoring in ultrasonic metal welding of battery tabs

Real-time monitoring and control of temperature in ultrasonic joining of battery tabs and coupons are important for the quality improvement and cost reduction of battery assembly. However, there have always been difficulties in accurate and real-time measurement of temperature by conventional sensors for practical implementation. In this study, an innovative method is developed to provide an enabling technology for the in situ transient temperature monitoring, which could provide reliable feedback signals for potential control of ultrasonic joining processes. Micro thin film thermocouples (TFTCs) were fabricated on thin silicon substrates, which were then inserted in the welding anvil as a permanent feature so that the sensors were always located about 100 μm directly under the welding spot during joining of multilayer Ni-coated Cu thin sheets for battery assembly. Good repeatability was demonstrated while a temperature rise of up to 650 °C was obtained due to the closeness of the sensors to the welding spot. The inserts with thin film sensors remained functional after welding experiments. This method has a great potential for in situ transient temperature monitoring, and thus the control of ultrasonic joining processes to realize a practical smart joining system.     

旋转机械整周期数据采集

介绍了旋转机械整周期数据采集技术,提出了一种基于软件LABVIEW编程的方法,用光电编码器脉冲作为触发源,使用ADLINK DAQ2206数据采集卡采集的实验方案。采用整周期数据采集不仅能方便获得旋转机械的特征信息,而且方便数据的处理。     

Striation Formation and Melt Removal in the Laser Cutting Process

The mechanisms of melt ejection and striation formation in continuous wave laser cutting of mild steel are discussed. Melt ejection from the cutting front is shown to be a cyclic phenomenon. Striation formation is strongly affected by the oscillatory characteristic of the thin liquid film on the cutting front during melt ejection, together with the oxidation and heat transfer process. Cutting speed determines whether the liquid film will rupture or generate waves on the cutting front. Theoretical explanations are given according to the instability theory of a thin liquid film in a high-velocity gas jet and the diffusion-controlled oxidation theory. Striation frequency and depth are predicted according to the above theories. Experimental investigations were carried out and the results are consistent with the calculations. The better understanding has shed light on further investigations and optimal process development.     

基于模糊评价算法的环境检测系统的设计研究

人们工作与生活的环境越来越多的受到社会关注,面向室内工作场所,建立一种针对室内环境空气等级的评价方法具有重要的实践价值.采用ARM嵌入式硬件平台,linux操作系统,利用多种传感器对环境数据进行采集,以温度、湿度、甲醛含量、CO2浓度以及粉尘含量做为评价因素,根据五种参数的权重和耦合关系,对环境进行综合评定.系统具有实时数据采集、数据分析、数据显示、评价因子增添和删除、自定义评价范围和评价结果显示等功能.模糊综合评价理论兼顾了主观与客观的事实,对于不同环境具有相对灵活性.     

Thermal Characterization of the Chip-Tool Interface When Using Coated Turning Inserts

This paper reports some results of extensive experimental investigations of the thermal interactions between the coating/substrate and the moving surface of the chip. Semi-orthogonal cutting when bar turning a medium carbon steel and an austenitic stainless steel was carried out. Both flat-faced and grooved inserts coated with TiC, TiC/TiN, and TiC/Al₂O₃/TiN were tested. A standard K-type thermocouple embedded in the workpiece was used to convert measured efm's to the interfacial temperatures. In addition, the chiprake contact length and the area of contact were determined by using computer processing of scanned contact images. The minimum steady-state temperature at the interface between the moving chip and the coating-substrate system was explained in terms of the heat flux intensity and the thermal properties of both components of a unique closed tribo-system.     

Process capability study of laser assisted micro milling of a hard-to-machine material

Laser assisted micro milling (LAMM) is capable of generating three-dimensional micro scale features in hard-to-machine materials. This paper compares the process capability of LAMM with conventional micro milling of a hardened tool steel. In particular, the potential advantages of LAMM over micro milling with respect to cutting forces, tool wear, material removal rate, burr formation and surface roughness are investigated when micro milling hardened A2 tool steel (62 HRC). The results show that LAMM has significant advantages over micro milling, especially in terms of cutting forces, material removal rate and tool wear. The average reduction in the resultant cutting force is found to be up to 69% with laser assist. In addition, tool wear is found to be substantially less with laser assist even when the material removal rates are increased by a factor of six over the tool manufacturer recommended cutting conditions.     

Automated micro-transfer printing with cantilevered stamps

This paper demonstrates the use of a flexible instrumented stamp to enable automated micro transfer printing as a route to large-area, deterministic assembly of microstructured device components or ‘inks’. The ability to instrument the stamp, a critical component for retrieval and placement of a micro device, to detect contact and monitor localized forces during critical events in the printing process not only allows for the development of a robust manufacturing process, but also for a unique vantage point from which to study fundamental issues and phenomena associated with adhesion and delamination of thin films from a variety of substrate materials. This paper presents basic design analysis on the requirements of the cantilevers for compatibility with a typical transfer printing environment. Off-the-shelf thin film strain gages are integrated with a thin elastomeric post as a preliminary prototype and the feasibility of transfer printing with it is demonstrated. Further, the set-up is calibrated to produce force signals for event detection and in situ diagnosis of the process.     

基于3S的污染源在线监控系统研究

污染源在线监控系统基于B/S模式作为整体系统的架构,主要是用GPS对重点污染源进行空间定位,以ArcG IS Server空间地理信息系统为分析和决策基础,利用GPRS网络进行数据采集和传输,将工业监测仪的分析数据实时传送到数据中心,利用监控系统的分析功能对数据进行切割抽取,自动生成监控曲线和监控图形,并结合视频监控,实现对污染源的立体性监控和管理,实时掌握各企业污染物的排放情况。     

An Approach to Theoretical Modeling and Simulation of Face Milling Forces

A new approach to theoretical modeling and simulation of face milling forces is presented. The present approach is based on a predictive machining theory in which machining characteristic factors in continuous cutting with a single-point cutting tool can be predicted from the workpiece material properties, tool geometry, and cutting conditions. The action of a milling cutter is considered as the simultaneous work of a number of single-point cutting tools, and the milling forces are predicted from input data of workpiece material properties, cutter parameters and tooth geometry, cutting condition, cutter and workpiece vibration structure parameters, and types of milling. A predictive force model for face milling is developed using this approach. In the model, the workpiece material properties are considered as functions of strain, strain rate, and temperature. The ratio of cutter tooth engagement over milling is taken into account for the determination of temperature in the cutting region. Cutter runout is included in the modeling for the chip load. The relative displacement between the cutter and workpiece due to the cutter and workpiece vibration is also included in the modeling to consider the effect on the undeformed chip thickness. A milling force simulation system has been developed using the model, and face milling experimental tests have been conducted to verify the simulation system. It is shown that the simulation results agree well with experimental results.     

高原型航空地面电源数据采集系统设计

为了采集航空地面电源在高原环境下的运行状态参数,给出了一种基于S3C2440的高原型地面电源数据采集系统硬件和软件设计方案。系统通过应用S3C2440处理器控制多路模拟开关,利用分时复用技术将地面电源多路传感器数据送入数据采集卡。将所获得的数据存储到可移动存储设备中。为了方便用户与系统之间的交互,还提供了生成报表、存档、打印输出等功能。系统分析软件能够直观地观察特征参数的详细情况,通过编程实现对实验结果数据的复现,运行曲线显示、数据表格显示。     

Micro dimple milling on cylinder surfaces

The paper presents a micro dimple machining on a cylinder surface with a two-flutes ball end mill. When the cutter axis is inclined and the depth of cut is less than the tool radius, non-cutting time, during which neither of the two cutting edges contacts the workpiece, appears in a rotation of the cutter. The rotation of the workpiece and the feed of the tool are controlled so that the cutting areas do not overlap each other. In order to incline the tool with respect to the tangential direction on the cylinder surface, the tool is located at a position oriented at 45° from the top of the cylinder. An analytical model is presented to control the shapes of the dimples with the cutting parameters. The presented machining is verified in cutting tests with measuring the shape and the profile of the dimples. Pre-machining operations are conducted to have a high cylindricity of the workpiece in longitudinal turning and polishing. The cutter runout of the tool is also eliminated by adjusting the orientation and the position of the tool in the collet chuck with measuring the cutting force. The micro dimples are machined accurately as they are simulated.     

基于物联网的智能环境污染检测与控制系统研究

为了实行对环境污染的远程智能检测,提出基于物联网技术的智能环境污染检测与控制系统设计方法,采用无线传感组网技术进行智能环境污染检测系统物联网设计,实现对环境污染信息采样,采集的环境污染数据主要有水污染数据、土壤污染数据和大气污染数据等。将数据输入的集成控制单元中,通过上位机进行远程传输控制,采用TMS320VC5409A智能处理DSP芯片作为集成控制芯片进行控制系统硬件设计,环境污染检测与控制系统硬件模块分为物联网传感模块、AD模块、上位机通信模块和数据输出接口模块等。在嵌入式Linux内核中实现环境污染检测程序加载,实现污染检测和优化控制。测试结果表明,采用该方法进行环境污染检测与控制的智能性较好,准确度较高,实时性较好,总体性能较优。     

Aero-lap polishing of poly crystalline diamond inserts using Multicon media

Increasing use of poly crystalline diamond (PCD) inserts as cutting tools and wear parts is vividly seen in automobile, aerospace, marine and precision engineering applications. The PCD inserts undergo series of manufacturing processes such as: grinding that forms the required shape and polishing that gives a fine finish. These operations are not straight forward as PCD is extremely resistant to grinding and polishing. Single crystal diamond can easily be polished by choosing a direction of easy abrasion, but polishing a PCD imposes serious difficulties as the grains are randomly oriented. Prior research on polishing of PCD inserts includes electro discharge grinding (EDG), dynamic friction polishing and grinding by a vitrified bonded diamond wheel. The surface textures of PCD produced using an EDG process often contains: micro cavities, particle pullout, micro-grooves, chipped edges, cracks and gouch marks. While applying the dynamic friction polishing method the PCD material undergoes phase transformation and hence increased polishing rate was apparently seen. However the phase transformation of PCD deteriorates the strength of the insert. Furthermore the inserts produced using the dynamic polishing method often exhibits cracks, chip off and edge damage while using as a cutting tool. Therefore, a new method “aero-lap polishing” was attempted as it applies controlled amount of impinging force by which the surface damage can be significantly reduced. The study did establish an improvement of surface finish of PCD from R_a = 0.55 μm, R_t = 4.5 μm to R_a = 0.29 μm, R_t = 1.6 μm within 15–25 min of polishing time along with significant reduction in surface defects.     

Novel Composite CBN-TiN Coating: Synthesis and Performance Analysis

Cubic boron nitride (CBN) coating, due to its promising properties, is under development worldwide for machining and other related applications. To synthesize a continuous CBN coating by conventional vapor deposition methods (CVD/PVD), however, poses many challenges, such as metastable CBN phase stabilization, as well as the high levels of intrinsic stress developed during the growth. A novel combinatorial approach, which is under development in an effort to develop a CBN composite coating for cutting tools, is reported in this paper. The approach involves a two-step process consisting of electrostatic spray coating (ESC) of CBN particles, followed by chemical vapor infiltration (CVI) of TiN. The process is optimized to deposit a CBN-TiN composite coating with a thickness in excess of 10 μm on tungsten carbide inserts. Such coated tools have been successfully evaluated and tested for machining applications. For production on a commercial scale, the laboratory systems have been upgraded to industrial size. The outcome of scaling up from an experimental to an industrial-sized unit is reported in this paper. The industrial electrostatic spray coating unit, which can coat a batch of about 50 inserts in a couple of minutes, is currently being field tested.     

典型装甲车辆平台环境数据采集与数据库管理

通过54次不同条件下的跑车试验,使用温湿度和振动传感器采集了典型装甲车辆大量的平台环境数据。利用ASP＋SQL server2000设计了数据库管理软件,实现了对装甲车平台环境数据、二次数据、相关文献的有效管理和高效查询。     

Assessing the Performance of a Magnetostrictive-Actuated Tool Holder to Achieve Axial Modulations with Application to Dry Deep Hole Drilling

For machining operations such as drilling and tapping, the challenge of achieving dry machining is difficult due to the significant role that cutting fluid plays in lubrication and chip removal. A new approach for dry deep hole drilling of aluminum is presented. This new method utilizes a magnetostrictively actuated tool holder to modulate the axial position of a drill tip and thus vary the chip size. Under appropriate modulation conditions, small chips are produced that are relatively easy to evacuate through the drill flutes. The development of the magnetostrictive tool holder system is described and its performance is evaluated. The results of drilling tests performed with the magnetostrictive tool holder system are reported, and the new tool holder is demonstrated to offer promise as an alternative to drilling with a cutting fluid.     

基于计算机网络的大型空气污染远程报警系统设计研究

为了实现对空气环境污染的有效监测和报警控制,进行报警控制系统的优化设计,提出基于计算机网络的大型空气污染远程报警系统设计方法。系统包括了无线传感器网络模块、计算机控制模块、AD模块、时钟模块和人机交互模块。采用分布式无线传感器组网方法空气污染的原始数据采集,将采集的污染数据输入到AD模块中进行二进制转换,构建模拟预处理机进行控制信号放大滤波,采用DSP技术进行计算机控制程序设计,在计算机网络环境下实现大型空气污染远程报警系统的集成设计。系统测试结果表明,采用该方法进行大型空气污染远程报警系统设计具有很好的稳定性和兼容性,实现了空气污染的及时报警。     

基于GMS的武山矿区水文地质结构可视化模型

在介绍GMS生成水文地质结构实体模型方法的基础上,利用武山矿区大量钻孔数据,建立了该侵入岩矿区水文地质结构三维可视化模型。结果表明:将武山岩体的horizon ID设置为第7层,插入Q与T1d2—T2j之间建模取得了较好的效果;建立的可视化模型可以灵活地实现含水层的拆分组合、任意剖面及任意方向的旋转、切剖面等功能,并能清晰地展示含水层的空间分布特征,为了解水文地质结构特征、进一步挖掘地质与水文地质相关信息提供了方便。