scholarly journals In-Process Chatter Detection Using Signal Analysis in Frequency and Time-Frequency Domain

Machines ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 24
Author(s):  
Michele Perrelli ◽  
Francesco Cosco ◽  
Francesco Gagliardi ◽  
Domenico Mundo
Keyword(s):  
Wavelet Packet ◽  
Cutting Tools ◽  
Poor Quality ◽  
Machining Process ◽  
Surface Finishing ◽  
Work Piece ◽  
Chatter Detection ◽  
Machining Processes ◽  
Time Frequency ◽  
Working Parameters

All machining processes involve vibrations generated by structural sources such as a machine’s moving parts or by the interaction between cutting tools and work-pieces. Relative vibrations between the work-pieces and the cutting tool are the most relevant from the point of view of the regenerative chatter phenomenon. In fact, these vibrations can lead to a chip yregeneration effect, which results in unwanted consequences, rapidly degenerating towards a very poor quality of surface finishing or, in case of severe chatter conditions, to machine-tool or work-piece damage. In the past decades, two different approaches for chatter avoidance were proposed by the scientific community, and they are commonly referred to as Out-of-Process (OuP) and in-Process (iP) solutions. The OuP solutions are off-line approaches, which allow to properly set the working parameters before machining starts. Ip solutions are on-line techniques, which allow to dynamically change the working parameters during machining by using single or multiple sensors. By monitoring the machining process, iP algorithms try to keep the machining process in stable working conditions while keeping high productivity levels. This study dealt with a novel iP chatter-detection strategy based on the Power Spectral Density (PSD) analysis and on the Wavelet Packet Decomposition (WPD) of different sensor signals. The preliminary results demonstrate the stability and feasibility of proposed indicators for chatter detection in industrial application.

Beat Effect in Machining Chatter: Analysis and Detection

2020 ◽  
pp. 1-35
Author(s):  
Yuxin Sun ◽  
Longyang Ding ◽  
Chao Liu ◽  
Zhenhua Xiong ◽  
Xiang-Yang Zhu
Keyword(s):  
Wavelet Packet ◽  
Damping Ratio ◽  
Cutting Tools ◽  
Detection Methods ◽  
False Alarms ◽  
Chatter Detection ◽  
Machining Processes ◽  
Significance Level ◽  
Machining Chatter ◽  
Finish Cutting

Abstract In machining processes, regenerative chatter is an unstable vibration which adversely affects surface finish, cutting tools and spindle bearings. Under some cutting conditions, the beat effect, an interference pattern between two periodical vibrations of slightly different frequencies, has been a common phenomenon where the amplitude of chatter vibration tends to increase and decrease periodically. Until now, few studies have been conducted to analyze the beat effect in machining chatter. On the other hand, researchers have developed various chatter detection methods with the objective to timely avoid detrimental effects induced by chatter. However, none of existing chatter detection methods in the literature has ever considered the beat effect. The neglect of the beat effect will adversely affect the effectiveness of these methods and even result in false alarms. In this paper, the significance level and the mechanism of the beat effect in turning chatter are analyzed by the stability lobe diagram and time domain simulation. Afterward, a multiscale wavelet packet entropy (MWPE) method is proposed to detect machining chatter regardless of the occurrence of the beat effect. The determination strategy of the scale factor in the MWPE is presented based on the beat period, whose relationship with the damping ratio and spindle speed is derived analytically in orthogonal turning scenarios. Finally, machining tests are conducted to verify the feasibility and effectiveness of the proposed chatter detection method with respect to the presence and absence of the beat effect.

scholarly journals Dispositivos De Interrupcion Subia (Dis) Para El Analisis De Raices Viruta

2014 ◽  
Vol 2 (2) ◽  
Author(s):  
Diego Alejandro Neira Moreno
Keyword(s):  
Cutting Tool ◽  
Cutting Tools ◽  
Scientific Research ◽  
Cutting Process ◽  
Work Piece ◽  
Mechanical Forces ◽  
Machining Processes ◽  
Research Instrument ◽  
Machined Parts ◽  
Interaction Phenomena

El estudio de las variables y efectos derivados del mecanizado provee herramientas de conocimiento tendientes a optimizar el uso de las herramientas y los procedimientos de maquinado industrial. Este artículo de reflexión aborda el uso de los dispositivos de interrupción súbita (DIS) como herramientas de obtención de raíces de viruta para la investigación científica del mecanizado industrial, y para el estudio de los efectos derivados de la interacción entre las herramientas de corte y el material de trabajo, en función de los cambios microestructurales del material de trabajo, dependientes de la temperatura producida y los esfuerzos mecánicos de la herramienta de corte durante el mecanizado. Mediante la reflexión se destaca la importancia de los DIS como instrumentos de investigación científica en la manufactura, ya que estos permiten obtener muestras de viruta para estudiar las variables incidentes en el maquinado y a partir de esta evidencia, proponer alternativas para optimizar la fabricación de piezas y la integridad de las herramientas empleadas en el proceso.AbstractThe study of the variables and effects derived from the machining processes brings the knowledge needed to optimize the use of machining tools and procedures. This article is an opinion piece about the use of quick stop devices (QSD) as a scientific research instrument in machining projects to obtain chip roots, to study the interaction phenomena between cutting tool and work piece material that depends on temperature and the mechanical forces produced by the cutting tool during the cutting process. This article deals about how important the QSD are as a research instruments in manufacture because with this instruments it is possible to analyze the machining variables, based on the evidences bring by the chip roots obtained with the instrument. It is possible to propose optimization alternatives in the manufacture of machined parts and the integrity of cutting tools.

scholarly journals Pengaruh Parameter Pemesinan terhadap Kualitas Hasil Potong Mesin Bubut Maximat V13 pada Benda Kerja Poros PVC

2019 ◽  
Vol 2 (02) ◽  
pp. 19-24
Author(s):  
Kasijanto Kasijanto ◽  
Sadar Wahjudi ◽  
Listiyono Listiyono ◽  
Muhammad Fakhruddin
Keyword(s):  
Metal Cutting ◽  
Cutting Process ◽  
Machining Process ◽  
Work Piece ◽  
Machining Processes ◽  
Cutting Surface ◽  
Spindle Rotation ◽  
Feeding Speed ◽  
Tool Types

Metal cutting process (cutting process) is to cut metal to get the shape and size and quality of the planned cutting surface. The metal cutting process is carried out with special tools, according to the type of cutting process. So the tools for one process cannot be used in another process, even for similar processes, the tools cannot be exchanged if the cutting plans are not the same. Lathe process is a machining process to produce cylindrical machine parts which are carried out using a Lathe. Its basic form can be defined as the machining process of the outer surface of cylindrical or flat lathe objects. Polyvinyl Chloride, commonly abbreviated as PVC, is the third-order thermoplastic polymer in terms of total usage in the world, after Polyethylene (PE) and Polypropylene (PP). Worldwide, more than 50% of PVC produced is used in construction. PVC is produced by polymerizing vinyl chloride monomers (CH2 = CHCl). Because 57% of its mass is chlorine, PVC is the polymer that uses the lowest petroleum feedstock among other polymers. This research follows up the selection of configuration of the lathe machining process using plastic work pieces. In this study, Maximat V13 lathe and PVC type plastic were used. The variation of machining processes are spindle rotation (320, 540, and 900 rpm), feeding speed (0.07, 0.14, and 0.28), the use of tool types (carbide and HSS) and cooling (without cooling, coolant, and oil). So, with this research, it is expected that the optimal parameters in determining the configuration of the lathe machining process on a PVC work piece to produce a good turning surface can be achieved  

Determination of the Optimal Path of Three Axes Robot Using Genetic Algorithm

2019 ◽  
Vol 44 ◽  
pp. 135-149
Author(s):  
Sid Ahmed Dahmane ◽  
Abdelkader Megueni ◽  
Abdelwahab Azzedine ◽  
Abdelkader Slimane ◽  
Abdelkader Lousdad
Keyword(s):  
Optimal Path ◽  
Cutting Tools ◽  
Machining Process ◽  
Work Piece ◽  
Drilling Process ◽  
Genetic Optimization ◽  
Machining Time ◽  
Planning And Scheduling ◽  
Cylindrical Holes

Drilling is a chip machining process widely used in manufacturing .The term drilling includes all methods for making cylindrical holes in a work piece with chip cutting tools. There are many applications where drilling is used, such as drilling holes in PCBs. Robotic systems are used today to perform the drilling process. A problem that affects the use of these systems is the drilling sequence, as there are usually a number of points to visit. The determination of the drilling sequence is similar to the problem of synchronization of movement and travel time. The main objective is to optimize the time and trajectory of the three axes robot equipped with an automatic drill that seeks the best performance. In this paper, we have built a genetic optimization and problem solving algorithms to shorten the machining time to drill a given group of holes and reduce machining costs in order to improve the efficiency of the machining process as well robotic machining with three axes without degradation of the precision of the movement. The results of the experiments show that the proposed approach is feasible and practical. It is particularly useful in planning and scheduling systems for real-time manufacturing processes.

Development and Application of Coated Ceramic Cutting Tools

2006 ◽  
Vol 45 ◽  
pp. 1155-1162 ◽  
Author(s):  
E. Uhlmann ◽  
T. Hühns ◽  
S. Richarz ◽  
Walter Reimers ◽  
S. Grigoriev
Keyword(s):  
Cutting Tools ◽  
Substrate Material ◽  
Machining Process ◽  
Machining Processes ◽  
Ceramic Substrates ◽  
Pvd Coating ◽  
High Temperature Alloys ◽  
Pre Treatment ◽  
Process Measurements ◽  
Comprehensive Measurement

Ceramics are characterized by their special wear and temperature resistance. Thus, they are especially suited for the cutting of high-temperature alloys and difficult-to-cut materials. Due to their low ductility, they show brittle-hard properties during the process, which lead to a sudden failure of the tool. But it is possible to create composite materials that counteract the brittle-hard behavior of the substrate material by PVD-coating. The objective of the investigations is to increase the process stability of coated ceramic indexable inserts made of aluminum oxide and silicon nitride through the optimisation of the mechanical pre-treatment of the substrate materials. To this end, the ceramic substrates are pre-treated by different abrasive machining processes. Comprehensive measurement evaluations show the influence of the machining process and strategy on the formation of surface and subsurface. The workpieces ground and lapped in different ways are subsequently coated by an especially developed PVD process. Measurements show the influence of the pre-treatment on the surface structure and on the mechanical properties of the composite material. The application of the developed and manufactured tools in cutting tests verifies the results of the measurements.

scholarly journals The Methodologies Adopted To Improve the Machinability in Die-Sinking EDM

2019 ◽  
Vol 9 (1S4) ◽  
pp. 645-647
Keyword(s):  
Tool Wear ◽  
Material Removal Rate ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
High Surface ◽  
High Hardness ◽  
Machining Process ◽  
Work Piece ◽  
Machining Processes

Electrical discharge machining (EDM) is one of the oldest nontraditional machining processes, commonly used in automotive, aerospace and ship building industries for machining metals that have high hardness, strength and to make complicated shapes that cannot be produced by traditional machining techniques. The process is based on the thermoelectric energy between the work piece and an electrode. EDM is slow compared to conventional machining, low material removal rate, high surface roughness, high tool wear and formation of recast layer are the main disadvantages of the process. Tool wear rate, material removal rate and surface quality are important performance measures in electric discharge machining process. Numbers of ways are explored by researchers for improving and optimizing the output responses of EDM process. The paper summarizes the research on die-sinking EDM relating to the improvements in the output response.

Inferring Hardness From High-Speed Video of the Machining Process

2008 ◽  
Author(s):  
Don R. Hush ◽  
Matthew T. Bement ◽  
Tim K. Wong
Keyword(s):  
High Speed ◽  
Video Data ◽  
Machining Process ◽  
Work Piece ◽  
Highly Qualified ◽  
Process Data ◽  
Machining Processes ◽  
Workpiece Material ◽  
High Speed Video ◽  
Multiple Classifier

This paper presents the results of a study to assess the feasibility of inferring workpiece material hardness from high-speed video data of chip formation obtained during a turning operation. The motivation for assessing hardness in situ comes from the fabrication of shaped charges, where spatial variation in hardness is known to affect the performance of the shaped charge. While other in-process data could be used for this purpose, video data are analyzed here because of the stand-off, non-contact advantages afforded. This is especially relevant for highly qualified machining processes for small-lot, high value parts where any interference with the process (e.g., introduction of cables near the machine tool) is undesirable. A multistep image processing procedure is presented which is used to extract several features from the video data. These features are then used to develop a classifier which can be used to predict work-piece hardness. Multiple classifier designs (Knn and Ratchet) are considered.

Prediction of Material Removal in Extrusion Honing of Hastelloy C22 Using Artificial Neural Network

2019 ◽  
Vol 895 ◽  
pp. 32-37
Author(s):  
V.R. Devadath ◽  
H.P. Raju
Keyword(s):  
Neural Network ◽  
Material Removal ◽  
Elevated Temperatures ◽  
Machining Process ◽  
Work Piece ◽  
Micro Machining ◽  
Machining Processes ◽  
Aqueous Corrosion ◽  
Feed Forward Back Propagation ◽  
Wide Range

The traditional finishing processes are incapable of producing required surface finish and other characteristics in difficult-to machine materials like Nickel based superalloys and also complex geometrical shapes of engineering components. Hence to achieve these goals non-traditional micro-machining processes have been developed. Extrusion honing (EH) is one of the non-traditional micro-machining process to debur, radius, polish, and remove recast layer of components in a wide range of applications. In this process material is removed from the work-piece by flowing abrasive laden medium under pressure through or past the work surface to be finished. Components made up of complex passages having surface/areas inaccessible to traditional methods can be finished to high quality and precision by this process. Hastelloy C22 offers resistance to both aqueous corrosion and attack at elevated temperatures and it is a difficult metal to machine using traditional techniques. In this study, micro finishing of internal surface of Hastelloy C22 material having predrilled passage diameters 7, 8, 9 and 10 mm have been performed in an indigenously built hydraulic operated one way extrusion honing setup. For the present EH process, patented polymer mixed with SiC abrasive at 35% volume concentration was used as carrier medium. The study was performed for 46, 54, and 60 grit sizes of SiC abrasive. The material removal in EH process varies with passage diameter and grit size of abrasives at each trial. A feed forward back propagation neural network model has been developed for the prediction of material removal and it has successfully predicted material removed in each trial of EH process.

Numerical-Experimental Correlation of Distortions Induced by Machining Process on Thin-Walled Nickel Super Alloy Forged Components

2012 ◽  
Vol 504-506 ◽  
pp. 1299-1304 ◽  
Author(s):  
Antonio del Prete ◽  
Antonio Alberto de Vitis ◽  
Rodolfo Franchi
Keyword(s):  
Numerical Models ◽  
Model Development ◽  
Aircraft Engine ◽  
Machining Process ◽  
Work Piece ◽  
Machining Processes ◽  
Thin Walled ◽  
Main Components ◽  
Machining Operations

AeroEngines main components made by nickel super alloys are mainly obtained by machining of large forged components. The work piece machining process generates some distortions that may also be relevant. In this contest, in many cases the removed volume in the machining operations represents a large percentage of the forged component in order to obtain the thin-walled wanted geometry. Due to this reason, the residual bulk stresses induced by the process history can lead to significant 3D geometric distortions in the machined component with unacceptable dimensions and shapes of the obtained product for comparison with the wanted geometry. Moreover, it is a matter of fact how, the final component distortions depend by the cutting strategy adopted in the machining process. The experimental study of such cutting strategies on real components are particularly time consuming and costly and for this reason the chance to study the problem using reliable numerical models it is particularly welcome. In the present work authors reports the numerical model development of the forging and machining processes needed for the production of a aircraft engine component and the comparison of the obtained results with the ones physically measured. The objective is to develop and validate a modeling method able to predicts the shape and the magnitude of the distortion induced by the machining operation on the considered component and to establish a possible strategy to suggest machining working steps able to improve the quality of the manufactured component reducing the needed production time.

Parametric Approach Model for Determining Electrical Discharge Machining (EDM) Conditions: Effect of Cutting Parameters on the Surface Integrity

2009 ◽  
Vol 83-86 ◽  
pp. 725-737 ◽  
Author(s):  
Wissem Tebni ◽  
M. Boujelbene ◽  
E. Bayraktar
Keyword(s):  
Surface Integrity ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Cutting Parameters ◽  
Surface Damage ◽  
Machining Process ◽  
Work Piece ◽  
Machining Processes ◽  
Steel Maker ◽  
Edm Process

Electrical discharge machining (EDM) is one of the earliest non-traditional machining processes. EDM process is based on thermoelectric energy between the work piece and an electrode. There are various types of products which can be produced by using the EDM such as dies and moulds. Today many parts used in aerospace and automotive industry and also final processes of surgical components can be finished by EDM process. A simple and easily understandable model was proposed for predicting the relative importance of different factors (composition of the steels and Electro Discharge Machining processing conditions) in order to obtain an efficient pieces. A detail application on the tool steels machined by EDM was given in this study. This model is based on thermal, metallurgical and mechanical and also in situ test conditions. It gives detail information on the effect of electrochemical parameters on the surface integrity and sub-surface damage of the material (Heat Affected Zone, HAZ), the level of residual stresses, and the surface texture. This approach is an efficient way to separate the responsibilities of the steel maker and machining process designer for increasing the reliability of the machined structures.

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