scholarly journals Improvement in Contact Strength of Si3N4/SiC Composite by Crack Healing

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Koji Takahashi ◽  
Keita Takahashi ◽  
Kotoji Ando
Keyword(s):  
Acoustic Emission ◽  
Cutting Tool ◽  
Indentation Test ◽  
Machining Process ◽  
Surface Cracks ◽  
Contact Strength ◽  
Crack Healing ◽  
Machining Processes ◽  
Contact Loading ◽  
Ceramic Components

Ceramics have been used as bearing and cutting tool components, which are subjected to contact loading during their operation. The presence of surface cracks on these components decreases their contact strength. Thus, the reliability of ceramic components can be increased by improving their contact strength through crack healing. In the present study, the effects of crack healing on the contact strength of a silicon carbide-(SiC-) reinforced silicon nitride (Si3N4) composite subjected to various machining processes were investigated. The contact strength of this composite was evaluated using a sphere indentation test in which acoustic emission was used. The results showed that the contact strength of the composite improved when it was subjected to crack healing in combination with rapping; this was true even when the composite had cracks due to a heavy machining process.

A novel approach to machining process fault detection using unsupervised learning

2020 ◽  
pp. 095440542093755
Author(s):  
Thomas McLeay ◽  
Michael S Turner ◽  
Keith Worden
Keyword(s):  
Fault Detection ◽  
Unsupervised Learning ◽  
Tool Path ◽  
Cutting Tool ◽  
Novelty Detection ◽  
Cutting Parameters ◽  
Machining Process ◽  
Machining Processes ◽  
Workpiece Material ◽  
Data Set

The most common machining processes of turning, drilling, milling and grinding concern the removal of material from a workpiece using a cutting tool. The performance of machining processes depends on a number of key method parameters, including cutting tool, workpiece material, machine configuration, fixturing, cutting parameters and tool path trajectory. The large number of possible configurations can make it difficult to implement fault detection systems without having to train the system to a particular method or fault type. The research of this article applies a novel method to detect the changing state of a process over time in order to detect faulty machining conditions such as worn tools and cutting depth changes. Unlike studies in the previous literature in this domain, an unsupervised learning method is used, so that the method can be applied in production to unfamiliar processes or fault conditions. In the case presented, novelty detection is applied to a multivariate sensor feature data set obtained from a milling process. Sensor modalities include acoustic emission, vibration and spindle power and time and frequency domain features are employed. The Mahalanobis squared-distance is used to measure discordancy of each new data point, and values that exceed a principled novelty threshold are categorised as fault conditions.

Integration of Vibration Absorbers in Milling Chucks

2019 ◽  
Author(s):  
Mihir Joshi ◽  
Matthias Weigold ◽  
Michael Schoell
Keyword(s):  
Cutting Tool ◽  
Slenderness Ratio ◽  
Dynamic Compliance ◽  
Engineering Industry ◽  
Machining Process ◽  
Vibration Absorber ◽  
Machining Processes ◽  
Dynamic Vibration Absorber ◽  
Dynamic Vibration ◽  
Machining Vibrations

Abstract The use of cutting tool systems with a high slenderness ratio is encountered in the machining of deep cavities in the mechanical engineering industry, especially in the manufacturing of tools and dies. Cutting tool systems with a large slenderness ratio, owing to their dynamic compliance, are prone to vibrations during machining processes. These vibrations affect the quality of the machining process and the life of machine components. Integration of a vibration absorber in the cutting tool system helps in the reduction of machining vibrations. The reduction in vibrations is due to a shift in the resonance frequency of the modified system. This experimental study presents the identification of design possibilities of a vibration absorber for integration in the cutting tool system. The mass and geometry of the vibration absorber are varied and its integration in the milling chuck is explored. Firstly, experimental modal analysis is conducted to determine the effects of the dynamic vibration absorber on the frequency response function of the modified cutting tool system. Secondly, the effects of the dynamic vibration absorber on the machining process for a range of technology parameters are illustrated. During the machining process, the cutting forces are measured using a three-component dynamometer in time domain. Finally, the results are evaluated based on process quality, i.e. surface roughness and analysis of cutting force signal in the frequency domain. This study provides an understanding of the relationship between the mass and the geometry of the vibration absorber integrated in the cutting tool system and their influence on process stability.

Real-Time Recursive Least Squares Identification and Control of Lathe Chatter: Implementation and Performance Issues

1997 ◽  
Author(s):  
Shilong Zhang ◽  
Karl B. Ousterhout
Keyword(s):  
Least Squares ◽  
Real Time ◽  
Cutting Tool ◽  
Machining Process ◽  
Recursive Least Squares ◽  
Digital Controller ◽  
Parameter Estimates ◽  
Machining Processes ◽  
Wear Rates ◽  
And Performance

Abstract In most machining processes, the large amounts of energy that are required to accomplish the machining can lead to the development of self sustained vibrations (chatter). If chatter does develop, it severely limits the production capabilities of the machine tool — typically resulting in longer production cycles and increased tool wear rates. In this paper, a method of controlling lathe chatter is proposed, simulated, and experimentally verified. To eliminate the chatter, a feed-forward digital controller and electro-hydraulic cutting tool actuator is employed. To account for the time varying nature of the tool/workpiece dynamics, a recursive least squares parameter estimation technique is used to estimate the dynamics of the machining process in real-time. These parameter estimates are then used by the digital controller to control the cutting force at the cutting tool/workpiece interface.

scholarly journals Non-Invasive Estimation of Machining Parameters during End-Milling Operations Based on Acoustic Emission

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5326
Author(s):  
Andrés Sio-Sever ◽  
Erardo Leal-Muñoz ◽  
Juan Manuel Lopez-Navarro ◽  
Ricardo Alzugaray-Franz ◽  
Antonio Vizan-Idoipe ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
End Milling ◽  
Low Cost ◽  
Milling Process ◽  
Machining Process ◽  
Measuring System ◽  
Depth Of Cut ◽  
Machining Parameters ◽  
Machining Processes ◽  
Non Invasive

This work presents a non-invasive and low-cost alternative to traditional methods for measuring the performance of machining processes directly on existing machine tools. A prototype measuring system has been developed based on non-contact microphones, a custom designed signal conditioning board and signal processing techniques that take advantage of the underlying physics of the machining process. Experiments have been conducted to estimate the depth of cut during end-milling process by means of the measurement of the acoustic emission energy generated during operation. Moreover, the predicted values have been compared with well established methods based on cutting forces measured by dynamometers.

scholarly journals Improvement of the Contact Strength of Al2O3/SiC by a Combination of Shot Peening and Crack-Healing

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Tomoya Oki ◽  
Hiroki Yamamoto ◽  
Toshio Osada ◽  
Koji Takahashi
Keyword(s):  
Fracture Toughness ◽  
Shot Peening ◽  
Zirconium Oxide ◽  
Surface Cracks ◽  
Contact Strength ◽  
Crack Healing ◽  
Composite Ceramics ◽  
Apparent Fracture Toughness ◽  
Heat Treated ◽  
High Crack

Al2O3/SiC composite ceramics with high crack-healing ability were subjected to shot peening (SP) using zirconium oxide shots with several peening pressures and shot diameters. Specimens subjected to SP were heat-treated in air to heal the surface cracks induced by SP. The residual stress, the apparent fracture toughness, and the Weibull distribution of the contact strength were investigated, revealing that the combination of SP and crack-healing is effective for increasing the contact strength and decreasing the scatter of the contact strength of Al2O3/SiC.

scholarly journals A Scientific Approach of using the DMAIC Methodology to Investigate the Effect of Cutting Tool Life on Product Quality and Process Economics: A Case Study of a Saudi Manufacturing Plant

2021 ◽  
Vol 11 (1) ◽  
pp. 6799-6805
Author(s):  
A. B. E. Aichouni ◽  
H. Abdullah ◽  
F. Ramlie
Keyword(s):  
Process Improvement ◽  
Tool Life ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Machining Process ◽  
Real Field ◽  
Manufacturing Plant ◽  
Manufacturing Companies ◽  
Machining Processes ◽  
Process Economics

One of the major priorities for manufacturing companies in the globalized economy is the ability to offer high-quality products to customers at the lowest production cost. Globally, process improvement methods and techniques are used to reduce waste and improve product and service quality. This paper aims to propose a systematic model based on process improvement methodologies and tools to help the manufacturing companies decide on cutting tool life and other manufacturing issues. This research seeks to prove that some common industry practices, such as changing cutting tools in machining processes, can significantly affect the economics of production and the overall performance of the plant. The research is mainly based on analyzing real field data using the DMAIC methodology to identify improvements in order to achieve a balance between economy and quality in a Saudi manufacturing plant. Although the study was concerned only with changing cutting tools in the machining process in an air conditioning plant, its findings and conclusions can be generalized to all manufacturing processes.

scholarly journals A Time–Frequency Acoustic Emission-Based Technique to Assess Workpiece Surface Quality in Ceramic Grinding with PZT Transducer

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3913 ◽  
Author(s):  
Martin A. Aulestia Viera ◽  
Paulo R. Aguiar ◽  
Pedro Oliveira Junior ◽  
Felipe A. Alexandre ◽  
Wenderson N. Lopes ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Surface Quality ◽  
Low Cost ◽  
Digital Signal ◽  
Ceramic Materials ◽  
Fast Response ◽  
Machining Process ◽  
Process Conditions ◽  
Time Frequency ◽  
Ceramic Components

Innovative monitoring systems based on sensor signals have emerged in recent years in view of their potential for diagnosing machining process conditions. In this context, preliminary applications of fast-response and low-cost piezoelectric diaphragms (PZT) have recently emerged in the grinding monitoring field. However, there is a lack of application regarding the grinding of ceramic materials. Thus, this work presents an analysis of the feasibility of using the acoustic emission signals obtained through the PZT diaphragm, together with digital signal processing in the time–frequency domain, in the monitoring of the surface quality of ceramic components during the surface grinding process. For comparative purpose, an acoustic emission (AE) sensor, commonly used in industry, was used as a baseline. The results obtained by the PZT diaphragm were similar to the results obtained using the AE sensor. The time–frequency analysis allowed to identify irregularities throughout the monitored process.

Experimental Study on the Machinability of Inconel 718 Alloy Using Coated Carbide Tool

2015 ◽  
Vol 787 ◽  
pp. 448-453
Author(s):  
M. Manohar ◽  
K. Jayakumar ◽  
Roy M. Cherian ◽  
Koshy M. George
Keyword(s):  
Inconel 718 ◽  
Cutting Tool ◽  
Operating Conditions ◽  
Machining Process ◽  
Work Piece ◽  
Machining Parameters ◽  
Machining Processes ◽  
Inconel 718 Alloy ◽  
Tool Materials ◽  
Coated Carbide

While machining a material, it is essential to understand the characteristics of work material for choosing the favorable condition of the material, appropriate cutting tool, machining parameters to achieve desired optimum output. Accordingly, researchers always devise their studies to improve the machining processes resulting in enhanced product quality and increased production rate simultaneously. Such machining studies on super-alloys attract significance, since they are oriented towards overcoming the difficulties involved in machined out a component. Generation of heat in the cutting zone and high cutting forces on the tool being experienced while machining super-alloys, are due to poor thermal conductivity and work hardening characteristics. Above factors contribute to two basic problems viz. the inability of the tool materials to give long tool life and the metallurgical damage to the machined components due to induced stresses. Among the super-alloys, Inconel 718 is the widely used heat resistant super alloy (HRSA), which withstands stringent operating conditions in high and cryo temperature environments for longer duration. Studies on understanding the behavior and the relationship between work piece material, cutting tool materials, cutting conditions and the process parameters is an essential requirement for establishing and optimizing the machining process and the present work is tailored towards this objective. In this work, Inconel 718 alloy was subjected to turning experiments and the experimental data collected was used for constructing empirical models whose performance was assessed through statistical approach. It is established that the models developed could be used for predicting the output parameters for a set of input of parameters through 2-D (surface) and 3-D (contour) plots.

Cutting Process Monitoring by Means of Acoustic Emission Method; Part I - New Approach of Acoustic Emission Sensor; Part II - Transformation of Acoustic Emission into Audible Sound

2006 ◽  
Vol 13-14 ◽  
pp. 105-110 ◽  
Author(s):  
Jan Zizka ◽  
Petr Hana ◽  
L. Hamplova ◽  
Z. Motycka
Keyword(s):  
Acoustic Emission ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Data Gathering ◽  
Modern Society ◽  
Body Part ◽  
Electrical Signal ◽  
Machining Process ◽  
Acoustic Emission Sensor ◽  
Audible Sound

Development of modern society is converging to a status where many human actions can be performed by machines. To achieve production without human intervention, machines require artificial receptors. Data gathering for processing and analysis of signals, together with determination of feedback reactions can be achieved by a suitable decision maker unit. A sensed value suited to this so-called intelligent sensing process would be the acoustic emission signal. In the case of intelligent cutting tools this would require miniature highly sensitive sensors integrated into the cutting tool body. Part I of this paper deals with the possibility of practical usage of the piezoelectric properties of copolymer foils for the acoustic emission sensor as a transducer of a mechanical surface wave into electrical signal. Part II of the paper deals with the most fundamental requirement for monitoring of cutting conditions during machining, i.e. excellent processing of measured data. Data obtained from machining process obtained by means of acoustic emission sensors, as discussed in the first part of this article, have high-frequency and continuous character of a white noise. These data are very difficult to process. New apparatus for transformation of acoustic emission into audible sound in the workplace is presented. The first stage of processing is by listening to transformed data it is subjectively possible to recognize differences in audible spectrum, corresponding to different states of the cutting tool. The second step is visualization of the differences via the fast Fourier transform (FFT) in the spectrum graphic chart.

Experimental Study of Laser Texturing Processes on the Lubricant Retention of Carbide (WC-Co) Surfaces

2019 ◽  
Vol 813 ◽  
pp. 55-61
Author(s):  
Juan Manuel Vázquez-Martínez ◽  
Irene Del Sol ◽  
Moises Batista ◽  
Severo Raúl Fernández-Vidal ◽  
Pedro M. Hernandez ◽  
...  
Keyword(s):  
Cutting Tool ◽  
Cutting Tools ◽  
Scanning Speed ◽  
Machining Process ◽  
Cutting Fluids ◽  
Laser Texturing ◽  
Machining Processes ◽  
Wide Range ◽  
Machined Parts ◽  
Cutting Processes

Machining process usually involves relevant wear effects on the cutting tool, producing undesirable surface features on the work-pieces. Lubricants and cooling fluids are used with the aim to minimize the wear phenomena as well as high temperatures produced during the cutting processes. However, the use of these fluids may have an adverse environmental impact. For this reason, the reduction of quantity of cutting fluids used in the machining process is a requirement in order to improve the performance and sustainability of the process. For this purpose, this work proposes an increase of the lubricant retention ability for cutting tools based on surface modification. In this research, micro-geometrical features of Carbide (WC-Co) surfaces have been modified by laser texturing techniques. A wide range of roughness topographies had been developed by changing the laser irradiation parameters of energy density of pulse (Ed) and scanning speed of the beam (Vs). Different geometries of the textured tracks (single spots, linear tracks, circular tracks) also were studied. Moreover, through specific roughness features conducted by texturing process, the retention ability of cutting fluids was modified. It was evaluated by the contact angle between liquid and solid phases. This modification allowed to increase the self-lubricant effect of the WC-Co surface. This methodology has been validated on carbide tools under lubricated machining processes. Wear effects on the cutting tool were reduced and the surface finish of the machined parts was remained at least in the same ranges as non-modified tools.

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