Design of an instrumented smart cutting tool and its implementation and application perspectives

This paper presents an innovative design of a smart cutting tool, using two surface acoustic wave (SAW) strain sensors mounted onto the top and the side surface of the tool shank respectively, and its implementation and application perspectives. This surface acoustic wave-based smart cutting tool is capable of measuring the cutting force and the feed force in a real machining environment, after a calibration process under known cutting conditions. A hybrid dissimilar workpiece is then machined using the SAW-based smart cutting tool. The hybrid dissimilar material is made of two different materials, NiCu alloy (Monel) and steel, welded together to form a single bar; this can be used to simulate an abrupt change in material properties. The property transition zone is successfully detected by the tool; the sensor feedback can then be used to initiate a change in the machining parameters to compensate for the altered material properties.The UK Technology Strategy Board (TSB) for supporting this research (SEEM Project, contract No. BD266E

Design and application of a wireless torque sensor for CNC milling

A Smart Machining System for Computer Numerical Control (CNC) Milling continually adjusts the cutting process parameters to optimize for cutting tool life and material removal rate. The system depends on sensors to gather information from the machine during cutting, but commercially available sensors detract from the effectiveness of the cutting system by lowering the system stiffness. This research focuses on the development of the electronics for a Smart Tool Holder (STH) and potential applications such as measurement of mechanical cutting power and suppression of chatter. The STH is a standard milling tool holder modified to hold a torque strain gauge bridge, a thermocouple and a Bluetooth radio transmitter. The STH is meant to overcome some of the different limitations imposed by bed dynamometers, microphones and spindle power sensors without reducing the system stiffness. Comparison of the mechanical power estimates from the STH and a conventional power sensor showed 10% difference

Wireless Sensor Integrated Tool for Characterization of Machining Dynamics in Milling

A first step towards practical sensing in the machining environment is the development and use of low cost, reliable sensors. Historically, the ability to record in-process data at an end mill tool tip has been limited by the sensor location. Often, these sensors are mounted on the material workpiece or the machine spindle at significant physical distance from the cutting process. Of specific interest are the problems of tool chatter which causes limitations to productivity and part quality. Although tool chatter is a substantial issue in machining, it remains an open research topic. In this research, a sensor integrated cutting tool holder is developed to specifically analyze the problems related to tool chatter. With the sensor integrated cutting tool holder, the signal to noise ratio is higher than traditional sensing methods. Because of the higher sensitivity, new data analysis methods can be explored. Specifically, the sensor is used in conjunction with a data dependent linear predictive coding algorithm to demonstrate effective prediction of chatter frequencies from stable cutting

Calibration and characterization of a low-cost wireless sensor for applications in CNC end milling

Central to creating a smart machining system is the challenge of collecting detailed information about the milling process at the tool tip. This work discusses the design, static calibration, dynamic characterization, and implementation of a low-cost wireless sensor for end-milling. Our novel strain-based sensor, called the Smart Tool, is shown to perform well in a laboratory setting with accuracy and dynamic behavior comparable to that of the Kistler 3-axis force dynamometer. The Smart Tool is capable of measuring static loads with a total measurement uncertainty of less than 3 percent full scale, but has a natural frequency of approximately 630 Hz. For this reason, signal conditioning of the strain signal is required when vibrations are large. Several techniques in signal processing are investigated to show that the sensor is useful for force estimation, chatter prediction, force model calibration, and dynamic parameter identification. The presented techniques include a discussion of the Kalman filter and Weiner filter for signal enhancement, Linear Predictive Coding for system identification, model-based filtering for force estimation, and sub-optimal linear filters for removing forced vibrations

Design and research of cutting load measuring device for coal and rock

Based on the analysis of the present situation of the research on the cutting process of the drum, the research method of the equipment capable of obtaining the cutting force in the drum cutting process is proposed by combining the finite element explicit dynamic analysis. Aiming at the complicated force of the shearer’s pick cutter in cutting the coal rock. In this paper, the finite element software is used to explicit dynamics simulate the picking of coal mining in the cutting process, and the strain distribution on the cutting is determined. Based on this, the use of strain gauge bridge design ideas to indirectly obtain the force on the cutter, and finally get the relevant experimental data. Compared with the finite element simulation analysis, the feasibility of the two schemes is explained, and the foundation of the follow-up experiment is laid

Development of computer controls for a goniophotometer

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (p. 23-24).The investigation of innovative window materials for redirecting light and thermal sources is an important component of the field of daylighting. The Heliodome system developed in the Building Technology department is a new type of goniophotometer for analyzing the spectral and angular properties of these materials. The Heliodome system relies on two cameras to transmit images to a user interface in order to provide immediate feedback to users. A filter wheel that divides the spectrum of visible and infrared light into separate wavebands for performing spectral analysis also needs to be integrated into the system to optimize the operation of the system by one user. The subject of this thesis is a control system that unifies the operation of the heliodome system. A wireless system has been developed to enable communication between the main user interface and the system camera without restricting the system's freedom of motion. Also, motors were selected and added to the filter wheel system to automate the filter changes and eliminate inaccuracy in the system. The modifications will enable the separate components of the Heliodome system to operate cohesively and allow architecture students to control the separate components from a single interface.by Javier Burgos.S.B

Bridges Structural Health Monitoring and Deterioration Detection Synthesis of Knowledge and Technology

INE/AUTC 10.0

An optical fiber measurement system design on tool radial vibration

The effects of tool radial vibration bring not only poor surface quality, inferior dimensional accuracy, but also disproportionate tool wear or tool breakage and excessive noise. Therefore, online measurement and monitoring of tool vibration are necessary. In order to monitor the tool vibration, an optical fiber measurement system was design in this pater. Firstly, the structure and basic principle of the optical fiber sensor was given; secondly, the light intensity to voltage converter circuit was introduced; then, an experiment platform was built for verify the feasibility of the optical measuring system, and the result shows that the radial vibration of a smooth 10 mm diameter shaft can be measured quickly

An Integrated Telemetric Thermocouple Sensor for Process Monitoring of CFRP Milling Operations

AbstractA wireless temperature measurement system was developed and integrated into a cutting tool holder via a thermocouple embedded within the cutting tool. The primary purpose of such an embedded thermal measurement sensor/system is for online process monitoring of machining processes within which thermal damage poses a significant threat both for the environment and productivity alike – as is the case with the machining of carbon fibre reinforced polymer (CFRP) components. A full system calibration was performed on the device. Response times were investigated and thermal errors, in the form of damping and lag, were identified. Experimental temperature results are presented which demonstrate the performance of the integrated wireless telemetry sensor during the edge trimming of CFRP composite materials. Thermocouple positioning relative to heat source effect was among the statistical factors investigated during machining experiments. Initial results into the thermal response of the sensor were obtained and a statistical package was used to determine the presence of significant main effects and interactions between a number of tested factors. The potential application of the embedded wireless temperature measurement sensor for online process monitoring in CFRP machining is demonstrated and recommendations are made for future advancements in such sensor technology