Query: A novel dynamometer for monitoring milling process

Candidate papers:

abstract: Cutting force measurement is an essential requirement in tool condition monitoring and offer an important indicator to design machine tools, optimize machining processes. In this paper, a novel cutting force dynamometer for measuring axial force and torque in milling is proposed. The new type sensing element has been developed to enhance the sensitivity of the dynamometer meanwhile to maintain enough rigidity. The device is based on semiconductor strain gauge that measures the deformation of lantern shape sensing element. In order to check the feasibility of the proposed dynamometer, a static calibration and modal impact test were carried out, and the performance of device installed on a milling machine has been tested under different cutting conditions. The results show that the dynamometer has a high performance and could be used as an instrument for monitoring machining process.
author_names: Yafei Qin

Yulong Zhao

Yingxue Li

You Zhao

Peng Wang
title: A novel dynamometer for monitoring milling process
year: 2017

abstract: In the milling process, cutting forces contain key information about the machining process status in terms of workpiece quality and tool condition. On line cutting force measurement is key for machining condition monitoring and machined surface quality assurance. This paper presents a novel instrumented working table with integrated polyvinylidene fluoride (PVDF) thin film sensors, thus enabling the dynamic milling force measurement with compact structures. To achieve this, PVDF thin film sensors are integrated into the working table to sense forces in different directions and the dedicated cutting force decoupling model is derived. A prototype instrumented working table is developed and validated. The validation demonstrates that profiles of the forces measured from the developed instrumented working table prototype and the dynamometer match well. Furthermore, the milling experiment results convey that the instrumented working table prototype could also identify the tool runout due to tool manufacturing or assembly errors, and the force signal spectrum analysis indicates that the developed working table can capture the tool passing frequency correctly, therefore, is suitable for the milling force measurement.
author_names: Ming Luo

Zenghui Chong

Dongsheng Liu
title: Cutting Forces Measurement for Milling Process by Using Working Tables with Integrated PVDF Thin Film Sensors
venue: Sensors
year: 2018

abstract: Abstract Tool geometry optimization, workpiece material characterization, process monitoring and optimization are based on the measurement of cutting forces by using machining dynamometers. Commercial dynamometers cover a wide range of machining applications, nevertheless there is a lack of measuring devices suitable for investigating milling and drilling applications with relatively small cutters and high spindle speeds. In this work, the development and testing of an innovative plate dynamometer designed for this purpose is discussed. The new measuring system was based on three high sensitive triaxial piezoelectric force sensors arranged in a novel triangular configuration. Component design was optimized by using FE numerical approaches, according to the general guidelines derived from mathematical modeling of sensor dynamics. The prototype of the proposed device was manufactured and experimentally tested against two high end commercial plate dynamometers by performing static calibration, modal analysis and cutting tests. Experimental results proved the excellent characteristics of the new device and its effectiveness for investigating advanced machining applications.
author_names: Giovanni Totis

O Adams

Marco Sortino

Drazen Veselovac

Fritz Klocke
title: Development of an innovative plate dynamometer for advanced milling and drilling applications
year: 2014

abstract: Tool wear is one of the most important parameters in micro end milling, and can be used to monitor the condition of the machine and the tool. A micro end mill has different characteristics from a macro scale end mill; in particular, shank run out (which is negligible in the macro scale tool due to the low aspect ratio) is significant in micro end milling, inducing excessive tool wear and reduced tool life and leading to sudden, premature failure. In this paper, a novel tool wear monitoring method is described for determining the state of a micro end mill using wavelet packet transforms and Fisher's linear discriminant. Force and torque signals were measured using a dynamometer and were used to reflect geometric changes in the micro end mill due to wear. Because of the small signal to noise ratio, sensor signals measured during the milling process were periodically averaged, and the resulting single period signals provided improved efficiency of feature extraction using wavelet packet transforms. The extracted features were classified in the wavelet domain and used to determine the tool state employing a hidden Markov model. The recognition results were compared with those of an energy based monitoring technique, and we found that our method could determine the tool state more accurately for both normal wear and premature failure of micro end mills.
author_names: Young-Sun Hong

Hae-sung Yoon

Jong-Seol Moon

Young Man Cho

Sung-Hoon Ahn
title: Tool wear monitoring during micro end milling using wavelet packet transform and Fisher's linear discriminant
year: 2016

abstract: Abstract Process monitoring and controlling with detailed real time information such as the cutting force is required for improving the performance of milling processes. This paper presents a novel system for measuring the cutting force in the direct vicinity of the indexable insert. The outlined concept makes use of piezoelectric thick film sensors mounted directly below the insert. The unique design and features of the new sensor enable accurate and continuous force measurements as well as the indication of wear. The results of the experimental investigations are presented and compared to results of a conventional dynamometer.
author_names: Welf-Guntram Drossel

Sylvia Gebhardt

Andre Bucht

Burkhard Kranz

Jorg Schneider

Martin Ettrichratz
title: Performance of a new piezoceramic thick film sensor for measurement and control of cutting forces during milling
year: 2018

abstract: The newly developed multi sensor system for a milling process sensor system is capable of simultaneously measuring six channels of machining signals using a rotating tool incorporating a wireless system. Furthermore, the system can be used to measure the spindle torque, Tq; tool vibration in the z axis, Az; tool tip temperature, Tm and the three components of the cutting force. Cutting force signals are generated by using a cross beam legged transducer embedded in the standard milling tool holder. A mini accelerometer is placed under the force transducer, whereas a thermocouple is positioned under a cutting tool insert close to the cutting edge. All signals are collected and sent to the data logger system via an inductive wireless transmitter unit incorporated into the standard rotating tool holder. The calibration, verification and real experimental machining test results reveal that the sensor system is both suitable and reliable for measuring machining signals. The measured signals are found to be importantly related to changes in the flank wear state. Therefore, this system can be used for real time tool condition monitoring in the milling process.
author_names: Muhammad Rizal

Jaharah A Ghani

Mohd Zaki Nuawi

Che Hassan Che Haron
title: An embedded multi sensor system on the rotating dynamometer for real time condition monitoring in milling
year: 2018

abstract: In this article, the design of an observer realized as an extended Kalman filter (EKF) is presented for a nonlinear thermoelectric system, characterized by a Peltier cell (PC) The task of the observer is to estimate the temperatures of the cold and warm side of the PCs, e.g. for control purposes. In particular, the cold side temperature is to be monitored in the cooling system that is used to clamp workpieces by freezing of water in a novel industrial manufacturing process. The estimation of these temperatures is done during the milling phase in which a mill generates an abrupt change in the temperature to be controlled. Through the developed EKF, a sensorless control can be realized in order to control the cold side temperature without the use of a sensor. Sensorless control has the advantages of minimizing costs, installation efforts, maintenance, measurement noise, and saving space in installation. Even during the milling phase, the EKF shows excellent estimation results that are obtained from real measurements obtained from a dedicated test bench.
author_names: Alexandra Mironova

Benedikt Haus

Andreas Zedler

Paolo Mercorelli
title: Extended Kalman Filter for Temperature Estimation and Control of Peltier Cells in a Novel Industrial Milling Process
venue: IEEE Transactions on Industry Applications
year: 2020

abstract: A tool condition monitoring (TCM) system is vital for the intelligent machining process. However, literature has mostly ignored the interaction effect between product quality and tool degradation and has devoted less attention to the criterion of integrated diagnostics and prognostics to cutting tools. In this paper, we aim to bridge the gap and make an attempt to propose a novel integrated tool condition monitoring system based on the relationship between product quality and tool degradation. First, a cost efficient experimentation concerning high speed CNC milling machining was implemented. Subsequently, a comprehensive correlation investigation was performed; revealing strong positive relationship exists between product quality and tool degradation. Mapping this relationship, an integrated TCM system pertaining to diagnostics and prognostics was proposed. Herein, the diagnostic reliability was enhanced by researching on the use of a multi level categorization of degradation. The prognostic competence was enhanced by formulating it explicitly for the tools critical zone as a function of tool life. The system is integrated in a manner that, whenever the degradation curve of the tool reaches the critical zone, prognostics module is triggered, and remaining useful life is assessed instantaneously. To enhance the performance of this system, it is modeled employing support vector machine with optimal training technique. The proposed system was validated based on the experimental data. An extensive performance investigation showed that the proposed system provides a robust problem solving framework for the intelligent machining process.
author_names: Amit Kumar Jain

Bhupesh Kumar Lad
title: A novel integrated tool condition monitoring system
venue: J. Intell. Manuf.
year: 2019

abstract: Abstract The cutting force provides significant information to help understand the machining process, optimization, tool condition monitoring, tool design and others. Hence, various methods of measuring the cutting force have been proposed by many researchers. In this work, an innovative integrated rotating dynamometer and tool holder is designed, constructed and tested that can fulfil the requirement to measure the cutting force in a wireless environment system. The device consists of a strain gauge based sensor that is mounted on a newly designed force sensing element which is then placed in the rotating tool holder. The force sensing element is designed in the form of a symmetrical cross beam type with four arms, shaped as a rectangular parallelepiped. This device is intended to be used in a rotating spindle such as in milling and drilling processes. A conditioning system and an inductive telemetry transmitter unit are incorporated into a modified tool holder in order to collect and transmit the cutting force signal to the data acquisition system. The rotating dynamometer has been subjected to a series of tests to determine its static and dynamic characteristics. Thus, it is tested experimentally by conducting cutting tests up to cutting speed 550 m/min with a single tool insert. The results show it is suitable and reliable to measure the cutting force in milling processes.
author_names: Muhammad Rizal

Jaharah A Ghani

Mohd Zaki Nuawi

Che Hassan Che Haron
title: Development and testing of an integrated rotating dynamometer on tool holder for milling process
year: 2015

abstract: Cutting force measurement is a crucial task aimed at improving process performance, since the cutting force contains important information about the condition of the process, such as tool condition and vibration. In the machining process of aircraft structural parts, the cutting force becomes a key factor which influences the qualified rate of product due to the low rigidity of aircraft structural parts. In order to monitor the cutting force, a novel force sensing element integrated into the fixture system for aircraft structural parts machining is proposed. Accordingly, a cutting force measuring model of a force sensing fixture system consisting of a set of the force sensing elements is developed, enabling the estimations of not only overall cutting forces but also dynamic contact forces caused by the cutting forces at different locating/clamping points. To validate the effectiveness of the force sensing element, a series of milling tests are conducted under both up and down milling with different cutting parameters, and the measured cutting forces are compared with a commercial dynamometer. Then, a series of analyses is carried out, and from the results, a satisfactory agreement with the forces measured by the dynamometer is achieved. Moreover, the median errors of the average resultant force are less than 6% compared with the dynamometer.
author_names: Dongsheng Liu

Yuanlin Hu

Dinghua Zhang

Huan Luo
title: Milling force monitoring with thin film sensors integrated into fixtures
venue: The International Journal of Advanced Manufacturing Technology
year: 2019