DOCSLIB.ORG

Comparative Analysis of Chatter Vibration Frequency in CNC Turning of AISI 4340 Alloy Steel with Different Boundary Conditions

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Comparative Analysis of Chatter Vibration Frequency in CNC Turning of AISI 4340 Alloy Steel with Different Boundary Conditions Journal of Covenant Engineering Technology (CJET) Vol. 1, No. 1, March 2018 An Open Access Journal Available Online Comparative Analysis of Chatter Vibration Frequency in CNC Turning of AISI 4340 Alloy Steel with Different Boundary Conditions Okonkwo Ugochukwu C.1, Nwoke Obinna N.2, Okokpujie Imhade P.3 1Department of Mechanical Engineering, Nnamdi Azikiwe University, P.M.B. 5025, Awka, Nigeria 2Department of Mechanical Engineering Technology, Akanu Ibiam Federal Polytechnic, Unwana, Ebonyi State. 3Department of Mechanical Engineering, Covenant University, P.M.B 1023, Ota, Ogun State, Nigeria Corresponding Author, [email protected] Abstract- In this study, an experimental investigation of chatter vibration frequency in CNC turning of AISI 4340 Alloy Steel material was carried out, with uncoated carbide tool insert (TPG 322) on Fanuc 0i TC CNC lathe machine, with two boundary conditions. The experimental design adopted for this study is the Taguchi parameter design with L9 orthogonal array. Turning tests were carried out on nine samples of the test-piece material for the clamped-free (C-F) condition, and the tests replicated on another set of nine test-pieces for Clamped-Pinned, so- called C-SS workpiece boundary condition. Chatter vibration frequencies were measured using MXC-1600 digital frequency counter and the frequency plots continuously analysed through DTO 32105 sound signal and frequency analyzer. The main objective is to investigate the process parameters’ performances on the work-piece material of AISI 4340 alloy steel, and to carry out comparisons between the two different boundary conditions vis-à-vis the effects of process parameters which are cutting speed, feed rate and depth of cut on the chatter vibration frequency for the orthogonal turning operation. Chatter vibration frequency values for the C-SS scenario were found to be up to 30% lesser when compared to the C-F machining scenario. Introduction of the tailstock used in pinning the free-end of the slender work-pieces reduced the chances that workpiece would bend; whereas absence of the pinned end means that workpiece may be skewed at an angle in the chuck with increased dynamic deflections at the free end leading to 13 Okonkwo Ugochukwu C., et al CJET Vol.1 No.1, March. 2018 (Special Edition) 13-30 more aggressive workpiece and cutting tool perturbations which are known to favour cutting instability. Keywords: CNC lathes machine, Chatter Vibration, Cutting Stability, Machining Parameters and Taguchi Method. I. Introduction Regenerative vibrations are the self- maximum cutting parameters, when excited vibrations which occur the limits should instead be defined during certain machining processes by the strength of the tool and the as a result of the interactions between power of the machine. It is never a the workpiece –machine tool good idea to keep machine in the structures and the cutting process face of strong chatter as chatter is dynamics. They are also referred to very bad for tool and machine life, as chatter vibration. Chatter is the and interferes with the accuracy of most obscure and delicate of all the the machining operation. Chatter can problems facing a machinist. feed on itself, much like the feedback It is a resonant phenomenon where on a loudspeaker “Public Address” the machine or work-piece vibrates. system that creates those terrible It can become quite violent and screeching noises. For that reason, it generate a distinctive loud noise. is sometimes called "regenerative Every system of spindle, tool holder chatter." The regenerative and tool has some set of frequencies phenomenon is key to understanding at which it naturally wants to vibrate. how chatter works. A vibration in the At certain higher spindle speeds, it tool leads to a wave in the work- becomes possible for cutting edges to piece; constant vibration creates a strike the part frequently enough that steady series of these waves. The the impacts cleanly synchronize with dynamic characteristics of the entire one of these natural frequencies. The machining system in terms of the smooth cutting that result, makes it natural frequencies, the damping possible to cut deeper without properties, flexural rigidity, and the straining the tool or the machine. stiffness of the machine tool Chatter is broadly classified in two structures, also affect the vibration categories: Primary chatter and magnitude. secondary chatter. Primary chatter is Chatter diminution remains obvious sub classified as frictional chatter, panacea for machining stability. thermo-mechanical chatter and Chatter avoidance techniques aim to mode-coupling chatter. Primary prevent chatter from occurring chatter is because of the friction during the machining process, by between tool and work piece and it selecting spindle speed and depth of diminish with the increase in spindle cut based on a stabilit chart the so- speed, while secondary chatter is a called stabilit lobe diagram as corollary of the regeneration of shown in igure 1. This was first waviness of the surface of the work introduced by Tobias and Fishwick piece [1]. [2]. If the process parameters are In numerous machining processes, above the stability borderline, chatter chatter is the barrier that defines the will occur, however, if the process 14 Okonkwo Ugochukwu C., et al CJET Vol.1 No.1, March. 2018 (Special Edition) 13-30 parameters are below the stability depth-of-cut below which stable borderline, chatter will not occur. machining is guaranteed regardless The critical stability borderline is the of the spindle speed. Figure 1: Stability Lobe diagram The lobed behaviour of the stability forced vibrations are extremely borderline allows stable lobe-regions small, the slightest marks left on the to form; thus, at specific ranges of cutting surface cause’s vibrations in spindle speeds, the depth-of-cut may the chip thickness for the following be substantially increased beyond the tooth or cut. This regenerative effect critical stability limit. These lobe- is the most important cause of regions become smaller as the chatter. For this reason it has become spindle speed decreases. However, a convention that “chatter” onl stability is increased at low spindle refers to regenerative chatter. It is speeds due to the process damping possible to distinguish between phenomenon [3]. In general, frictional chatter, mode coupling diminution of chatter technically chatter and regenerative chatter refers to a method to improve the based on the mechanism that causes stability margin in the cutting the vibration. Frictional chatter process. Various methods for chatter occurs when rubbing on the control have been proposed such as clearance face excites vibration in spindle speed manipulation or the direction of the tangential force variation and use of vibration and limits in the radial force absorbers. Vibration absorption direction. Mode coupling chatter method refers to adding an additional exists as the vibration in the radial mass to the structure to passively direction generates vibration in the absorb the unwanted vibration tangential direction and vice versa. energy [4-6]; whereas active control This results in simultaneous vibration requires external power to counteract in the tangential and radial force the unwanted vibration [7-10]. It is directions. This can be caused by a well documented that the number of sources such as friction on fundamental cause of chatter under the rake and clearance surfaces, chip most machining conditions is the thickness variation, shear angle regeneration effect [11]. Even when 15 Okonkwo Ugochukwu C., et al CJET Vol.1 No.1, March. 2018 (Special Edition) 13-30 oscillations and the regeneration in the cut, it encounters this wavy effect [12]. surface and generates a new wavy Regenerative chatter often occurs surface. The chip thickness and, because most cutting operations hence, the forces on the cutting tool involve overlapping cuts which can vary due to the phase difference be a source of vibration between the wave left by the amplification. Considering the previous tooth and the wave left by machining operation in igure 2, the the current one. This phenomenon combination of the waviness on the can greatly amplify vibrations, and surface left by the previous tooth and therefore instability. For the case of vibration of the currently cutting turning of slender workpieces, this tooth creates the periodically phenomenon is more common and changing chip thickness. In other pronounced especially when words, tool vibrations leave a wavy adequate nodal supports are not surface and when the cutting tooth is available. Figure 2: Schematic diagram showing a typical metal cutting action Machining parameters such as machining is strongly related to the cutting speed, feed rate, and depth of material removal rate. The material cut do affect the product quality and removal rate for a turning operation production costs. Thus, it is is given by the product of cutting important to use optimization parameters (cutting speed (Vc), feed technique to determine optimal levels rate (f), and depth of cut (d)). of these parameters so as to reduce Therefore, if an increase in the production costs and to achieve productivity is desired then an the desired product quality increase in these three cutting simultaneously [13]. One of the main parameters is required. But, there are objectives in the optimization of a limits to these cutting parameters turning process is minimization of since they also have an effect on the the cost of production and tool life, tool wear, cutting forces, maximization of the production rate cutting temperature and surface while keeping the quality of quality [15-22], when this process is machined parts as per design not well defined during machining specifications [14]. The cost of operation it can lead to fatigue, creep 16 Okonkwo Ugochukwu C., et al CJET Vol.1 No.1, March. 2018 (Special Edition) 13-30 and can increase the rate of to improve the quality of machining corrosions in our manufacturing operation with different boundary product [23,24].
Load more

Recommended publications
  • Multi-Rate Coupled Hidden Markov Models and Their Application To
    1 Multi-rate Coupled Hidden Markov Models and Their Application to Machining Tool-Wear Classification Ozg¨ ur¨ C¸etin,* Member, IEEE, Mari Ostendorf, Fellow, IEEE, and Gary D. Bernard Abstract— This paper introduces multi-rate coupled hidden measurements to the wear amount are not available for the Markov models (multi-rate HMMs for short) for multiscale mod- most part, or of limited capability. Therefore, much of the eling of nonstationary processes, extending traditional HMMs research on automatic wear prediction has focused on data- from single to multiple time scales with hierarchical repre- sentations of the process state and observations. Scales in the driven statistical methods. Initial work in this area used static multi-rate HMMs are organized in a coarse-to-fine manner with classifiers such as neural networks and Gaussian mixture Markov conditional independence assumptions within and across models (see, e.g., [13], [14], [50] for reviews), which do scales, allowing for a parsimonious representation of both short- not model any time-dependent characteristics in the sensory and long-term context and temporal dynamics. Efficient inference signals. Recent work with HMMs (e.g. [41] and [24] for and parameter estimation algorithms for the multi-rate HMMs are given, which are similar to the analogous algorithms for milling, [27] and [19] for drilling, and [52] for turning) have HMMs. The model is applied to the classification of tool wear in shown the utility of temporal information. For well behaved titanium milling, for which acoustic emissions exhibit multiscale materials, HMMs may be sufficiently powerful, but for other dynamics and long-range dependence.
    [Show full text]
  • Multi-Objective Optimization of Micro-Electrical Discharge Machining of T Nickel-Titanium-Based Shape Memory Alloy Using MOGA-II ⁎ Mustufa H
    Measurement 125 (2018) 336–349 Contents lists available at ScienceDirect Measurement journal homepage: www.elsevier.com/locate/measurement Multi-objective optimization of micro-electrical discharge machining of T nickel-titanium-based shape memory alloy using MOGA-II ⁎ Mustufa H. Abidia, Abdulrahman M. Al-Ahmaria,b, Usama Umera, , Mohammed Sarvar Rasheedc a Princess Fatima Alnijris Research Chair for Advanced Manufacturing Technology (FARCAMT Chair), Advanced Manufacturing Institute, King Saud University, Riyadh, Saudi Arabia b Industrial Engineering Department, College of Engineering, King Saud University, Riyadh, Saudi Arabia c Baynounah Institute of Science and Technology, Abu Dhabi Vocational Education Training Institute, Madinat Zayed, Abu Dhabi, United Arab Emirates ARTICLE INFO ABSTRACT Keywords: Shape memory alloys (SMAs) have received significant attention especially in biomedical and aerospace in- Micro-EDM (µEDM) dustries owing to their unique properties. However, they are difficult-to-machine materials. Electrical discharge Micro-machining machining (EDM) can be used to machine difficult to cut materials with good accuracy. However, several Shape memory alloy challenges and issues related with the process at micro-level continue to exist. One of the aforementioned issues MOGA-II is that the micro-EDM (µEDM) process is extremely slow when compared to other non-conventional processes, such as laser machining, although it offers several other benefits. The study considers the analysis and opti- mization of µEDM by using a multi-objective genetic algorithm (MOGA-II). Drilling of micro-holes is performed by using a tabletop electrical discharge machine. Nickel-Titanium (Ni-Ti) based SMA (a difficult to cut advance material) is used as a specimen. The objective involves determining optimal machining parameters to obtain better material removal rate with good surface finish.
    [Show full text]
  • Abstract Keywords 1. Introduction
    Kolluru, K.V., Axinte, D.A., Raffles, M.H., Becker, A.A. “Vibration suppression and coupled interaction study in milling of thin wall casings in the presence of tuned mass dampers”, Proc. IMechE, Part B: Journal of Engineering Manufacture, Vol. 228 (6), pp. 826-836, 2014. Vibration suppression in machining of thin wall casings through tuned mass dampers – A finite element analysis approach K Kollurua, D Axintea,*, M Rafflesa, AA Beckera, B Staplesb, P Wintonb a Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham, Nottingham NG7 2RD, UK b Rolls-Royce plc, Derby DE24 8BJ, UK Abstract Damping of machining vibrations in thin walled structures is an important area of research due to the ever-increasing use of lightweight structures such as jet engine casings. Previous work reported in the literature has focussed on passive and active damping solutions for simple planar thin walls; whereas vibration damping in thin wall ring type casings was not reported. Moreover, implementation of any of these solutions on an industrial scale component needs proven simulation tools for validation. In this work, a passive damping solution in the form of tuned viscoelastic dampers is studied to minimise the vibration of thin walled casings. The implementation of tuned dampers was driven by a specific characteristic observed for the casing under study where a couple of modes dominate the dynamic response. Finite element simulation studies are carried out for a casing both with and without passive dampers, and are validated using machining tests and experimental modal tests. The finite element predictions are found to match with experimental results with reasonable accuracy.
    [Show full text]
  • Vibration Analysis in Machining of Thin-Walled Workpieces Using Hilbert-Huang Transform by Agus Susanto March 2019
    Vibration analysis in machining of thin-walled workpieces using Hilbert-Huang Transform 㸦Hilbert-Huang Transform࡟ࡼࡿⷧ⫗ຍᕤ≀ࡢᶵᲔຍᕤ࡟ ࠾ࡅࡿ᣺ືࡢゎᯒ㸧 This dissertation is submitted in partial fulfillment of the requirements for the Doctor of Engineering degree at Department of Mechanical Systems Engineering, Graduate School of Engineering, Hiroshima University, Japan. by Agus Susanto Thesis Supervisor: Professor Dr. Eng. Keiji Yamada March 2019 i ABSTRACT OF DISSERTATION Agus Susanto Vibration analysis in machining of thin-walled workpieces using Hilbert-Huang Transform 㸦Hilbert-Huang Transform࡟ࡼࡿⷧ⫗ຍᕤ≀ࡢᶵᲔຍᕤ࡟࠾ࡅࡿ᣺ືࡢゎᯒ㸧 Thin-walled mechanical parts are widely used in industries in order to develop the light-weight structure of machine such as turbine blade, impeller, and aerospace frame. And they are often processed by machining operation, such as turning and milling. However, machining of these mechanical parts are more challenging than rigid ones. The main reason of this is that the dynamic properties, such as stiffness and damping, are very low. Therefore, machining of thin-walled mechanical parts can induce chatter vibration, accelerate tool wear, and lead machining error easily which are major obstacles in order to achieve desired products. In machining process, those negative phenomena are often monitored by analysis of vibration, cutting force, and temperature which are often measured by such kinds of sensors. The advanced sensors would exert their potential with an appropriate signal processing technique to extract the features of measured signals which provide an important information about machining states. Another word, signal processing is important to guarantee reliable results. In vibration analysis, researchers use many kinds of signal processing techniques for machining process monitoring.
    [Show full text]
  • Improving Machining System Performance Through Designed-In Damping Modelling, Analysis and Design Solutions
    Improving Machining System Performance through Designed-in Damping Modelling, Analysis and Design Solutions Lorenzo Daghini Doctoral Thesis KTH Royal Institute of Technology Department of Production Engineering Machine and Process Technology Stockholm, Sweden May 2012 TRITA IIP-12-05 ISSN 1650-1888 ISBN 978-91-7501-328-2 Akademisk avhandling som med tillstånd av Kungliga Tekniska högskolan framlägges till offentlig granskning för avläggande av teknologie doktorsexamen i Industriell Produktion den 4 maj 2012 i sal M311 “Brinellsalen”, Brinellvägen 68, Kungliga Tekniska högskolan, Stockholm Copyright © Lorenzo Daghini, 2012 Department of Production Engineering The Royal Institute of Technology S-100 44 Stockholm Tryck: Universitetsservice US AB 2 “You can't connect the dots looking forward; you can only connect them looking backwards. So you have to trust that the dots will somehow connect in your future. You have to trust in something – your gut, destiny, life, karma, whatever. This approach has never let me down, and it has made all the difference in my life.” Steve Jobs (1955-2011) Stanford commencement address, June 2005 Abstract With advances in material technology, allowing, for instance, engines to withstand higher combustion pressure and consequently improving performance, comes challenges to productivity. These materials are, in fact, more difficult to machine with regards to tool wear and especially machine tool stability. Machining vibrations have historically been one of the major limitations to productivity and product quality and the cost of machining vibration for cylinder head manufacturing has been estimated at 0.35 euro per part. The literature review shows that most of the research on cutting stability has been concentrating on the use of the stability limits diagram (SLD), addressing the limitations of this approach.
    [Show full text]
  • 9 VII July 2021
    9 VII July 2021 https://doi.org/10.22214/ijraset.2021.36446 International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.429 Volume 9 Issue VII July 2021- Available at www.ijraset.com Analyzing the Vibration Effect of Cutting Tool on Surface Roughness of Turning Work Piece in Lathe Machine Sawant Akshay Shasheekant1, Narwade Prashant2 1, 2Mechanical Engineering Department, Dr. Vitthalrao Vikhe Patil College of Engineering, Ahmednagar, India Abstract: Tool condition observation systems area unit essential in small milling applications. A tool's slenderness needs high- precision observation systems for on-line measurements. In most cases, tool health is indirectly calculable by process and analyzing the cutting method parameters cutlery wear may be a essential development that influences the standard of the machined half. Vibration signals from metal cutting processes are investigated for varied functions, together with in-process tool wear monitoring. Reducing the machining energy consumption (MEC) of machine tools for turning operations is important to market manufacturing producing. during this study, the link between vibration and gear wear is investigated throughout high- speed dry turning by victimization applied math parameters. it's aimed to show however tool wear and therefore the work piece surface roughness changes with tool vibration signals. For this purpose, a series of experiments were conducted in a lathe machine. Modal analysis of each traditional and wear cutlery are going to be perform for locating Natural frequency of cutting tools in ANSYS 19 code. Experimental testing of cutlery are going to be perform using FFT instrument.
    [Show full text]
  • Analysis and Prediction of the Machining Force Depending on the Parameters of Trochoidal Milling of Hardened Steel
    applied sciences Article Analysis and Prediction of the Machining Force Depending on the Parameters of Trochoidal Milling of Hardened Steel Michal Šajgalík 1 , Milena Kušnerová 2, Marta Harniˇcárová 1,2,*, Jan Valíˇcek 1,2, Andrej Czán 1, Tatiana Czánová 1,Mário Drbúl 1, Marian Borzan 3 and Ján Kmec 2 1 Department of Machining and Manufacturing Technology, Faculty of Mechanical Engineering—University of Zilina, Univerzitná 1, 010-26 Zilina, Slovakia; [email protected] (M.Š.); [email protected] (J.V.); [email protected] (A.C.); [email protected] (T.C.); [email protected] (M.D.) 2 Faculty of Technology, Institute of Technology and Business in Ceskˇ é Budˇejovice,Okružní 10, 370-01 Ceskˇ é Budˇejovice,Czech Republic; [email protected] (M.K.); [email protected] (J.K.) 3 Department of Manufacturing Engineering, Faculty of Machine Building, Technical University of Cluj-Napoca, B-dul Muncii, No. 103-105, 400641 Cluj-Napoca, Romania; [email protected] * Correspondence: [email protected] Received: 4 February 2020; Accepted: 2 March 2020; Published: 5 March 2020 Featured Application: One of the progressive machining methods for machining of exotic alloys is trochoidal milling. The main contribution of this paper is the analysis of basic parameters of trochoidal movement for the prediction of their impacts on the machining force. Knowledge of these predictions will make it possible to decide more effectively, on the selection of trochoidal parameters. Results from not only this paper, but our whole research on trochoidal milling are applied in various companies located near the city of the University of Zilina, such as IGV Technologies and LAGO instruments, but also local factories of well-known companies Volkswagen Slovakia, Schaeffler Kysuce, etc.
    [Show full text]
  • 5 Faces Machining in 1 Setup • 100% Steel Surface - Max Reliability • Automatic Self-Shimming
    APPLIED MONOLITHIC TECHNOLOGY Made in Italy GRIP FUNCTION MAGNETIC SYSTEMS FOR WORKPIECES CLAMPING IN MILLING OPERATIONS • 5 faces machining in 1 setup • 100% steel surface - max reliability • Automatic self-shimming INTERNATIONAL PATENTS Safety through power APPLIED MONOLITHIC TECHNOLOGY Magnetic systems for workpieces clamping on machine tools Magnetic systems are the optimal solution for the clamping of workpieces on milling machines, machining centres, pallets, squares and FMS systems. The main advantages: • Machining in one setup With a magnetic chuck the piece is always free on 5 sides; working with a single positioning optimizes the toolpath in face milling, contouring and drilling. The limits of traditional mechanical clamping systems are thus overcome: in fact, their presence obstructs the complete access to the component to be machined, forcing to multiple placements to complete the processing cycle. • Uniformity of clamping The clamping force is evenly distributed over the entire contact surface: the workpiece is not compressed or deformed. Traditional clamps are used to act by points, causing tensions that generate vibrations and machining resonances. • Quick positioning and fixing of the workpiece In a few seconds, through an electrical discharge, the magnetic circuit is activated and the workpiece is clamped. The power supply is required only for the phases of activation and deactivation. 2-3 APPLIED MONOLITHIC TECHNOLOGY MillTec characteristics: Monolithic technology • Monolithic technology MillTec series is a new generation of magnetic equipment, characterized by a monolithic Made from a block of steel, honeycomb structure, without mechanically- without any fixing elements assembled parts. • Permanent-electro safety The poles, obtained by core drilling from a Workpiece remains clamped single block of steel, are an integral part of even without power supply the frame and therefore capable of absorbing heavy operating efforts, maintaining absolute stability.
    [Show full text]
  • Experimental Study of Thin Part Vibration Modes in Machining
    EXPERIMENTAL STUDY OF THIN PART VIBRATION MODES IN MACHINING Toufic WEHBE, Gilles DESSEIN, Lionel ARNAUD Abstract: The machining of thin walls generally generates milling chatter, that damage surface roughness and manufacturing tools. Stability lobes which include natural frequencies are successful in case of tool chatter. When milling thin webs models are less adequate, because the interaction with the tool disrupts the behaviour of the work piece. The modal approach generally used for stability charts may be not adequate enough because of neglecting the tool and the work piece contact. This paper presents the experimental phase of a work aiming at analyse vibration modes of a thin web during machining. A finite element calculation shows the influence of a contact on natural frequencies of the part. For a better investigation, field displacements of the work piece are analysed. This work eventually aims at better knowledge of the contact between the tool and the part to improve the hardiness of models. Key words: Milling, chatter, flexible part, modal shape, displacement field. 1. INTRODUCTION plot stability charts. So the stability lobes theory neglects In milling operations, the machining system is prone the tool-part interaction. The disturbance brought to to vibratory phenomena that result from the dynamic natural modes by the tool presence remains ignored. A interaction between the tool and the part. These better comprehension of this effect requires knowing the vibrations called milling chatter generate a poor surface real vibratory behavior of the part during its machining. quality, the cutting edge chipping, and the tool and the Experimental works were done to analyze the spindle wear.
    [Show full text]
  • Prediction of Surface Roughness Based on Cutting Parameters and Machining Vibration in End Milling Using Regression Method and Artificial Neural Network
    applied sciences Article Prediction of Surface Roughness Based on Cutting Parameters and Machining Vibration in End Milling Using Regression Method and Artificial Neural Network Yung-Chih Lin 1,2, Kung-Da Wu 1, Wei-Cheng Shih 1, Pao-Kai Hsu 1 and Jui-Pin Hung 1,* 1 Graduate Institute of Precision Manufacturing, National Chin-Yi University of Technology, Taichung 41170, Taiwan; [email protected] (Y.-C.L.); ffi[email protected] (K.-D.W.); [email protected] (W.-C.S.); [email protected] (P.-K.H.) 2 Intelligent Machinery Technology Center, Industrial Technology Research Institute, Taichung 40852, Taiwan * Correspondence: [email protected]; Tel.: +88-6423-924-505 (ext. 7181); Fax: +88-6423-925-714 Received: 14 May 2020; Accepted: 3 June 2020; Published: 5 June 2020 Abstract: This study presents surface roughness modeling for machined parts based on cutting parameters (spindle speed, cutting depth, and feed rate) and machining vibration in the end milling process. Prediction models were developed using multiple regression analysis and an artificial neural network (ANN) modeling approach. To reduce the effect of chatter, machining tests were conducted under varying cutting parameters as defined in the stable regions of the milling tool. The surface roughness and machining vibration level are modeled with nonlinear quadratic forms based on the cutting parameters and their interactions through multiple regression analysis methods, respectively. Analysis of variance was employed to determine the significance of cutting parameters on surface roughness. The results show that the combined effects of spindle speed and cutting depth significantly influence surface roughness. The comparison between the prediction performance of the multiple regression and neural network-based models reveal that the ANN models achieve higher prediction accuracy for all training data with R = 0.96 and root mean square error (RMSE) = 3.0% compared with regression models with R = 0.82 and RMSE = 7.57%.
    [Show full text]
  • Product News Index WILL DEMONSTRATE MODULAR 8-SPINDLE AUTOMATIC CNC TURNING MACHINE at PMTS 2015
    product news Index WILL DEMONSTRATE MODULAR 8-SPINDLE AUTOMATIC CNC TURNING MACHINE AT PMTS 2015 Index will demonstrate its MS22C-8, a Each of the eight spindles, modular eight-spindle automatic CNC arranged in the Index spindle turning machine, producing brass con- drum, are assigned two cross- nector parts at PMTS 2015, Booth 400. slides which can travel on the The MS22-8 is designed for fast parts X-axis as well as the Z-axis. machining capability. Each cross-slide can be addi- The Index MS22C-8 has many appli- tionally equipped with a Y-axis. cations, from automotive to medical The speed of each of the eight technology. It can be bar-fed or loaded liquid-cooled spindles can be with chucked parts. controlled separately. The flu- The machine can be configured to id-cooled spindle drum keeps operate as an 8-spindle machine, a dou- the thermal growth in the spin- ble 4-spindle machine, dropping two dle carrier to a minimum. The complete parts at a time or a machine advantage compared to the pre- with double rear-end machining. The vious air-cooling approach is the higher ing two drum indexing cycles, up to six MS22C-8 in double 4-spindle mode power density in the spindle drum and tools can be used for this simultaneously runs as two machines working with one the capability of energy recovery from with the other spindles. another simultaneously on a single base. the heated cooling fluid. In addition, The advantage of hydrostatic sliding Every second tool station always has the spindle bearing temperature can be guide in the feed axis (Z) is their damping simultaneous access to the same tools.
    [Show full text]
  • Tool Wear in Titanium Machining
    UPTEC K12 006 Examensarbete 30 hp Juni 2012 Tool wear in titanium machining Stina Odelros Abstract Tool wear in titanium machining Stina Odelros Teknisk- naturvetenskaplig fakultet UTH-enheten The present work was performed at AB Sandvik Coromant as a part in improving the knowledge and understanding about wear of uncoated WC/Co cutting tools during Besöksadress: turning of titanium alloy Ti-6Al-4V. Ångströmlaboratoriet Lägerhyddsvägen 1 Hus 4, Plan 0 When machining titanium alloys, or any other material, wear of the cutting tools has a huge impact on the ability to shape the material as well as the manufacturing cost of Postadress: the finished product. Due to the low thermal conductivity of titanium, high cutting Box 536 751 21 Uppsala temperatures will occur in narrow regions near the cutting edge during machining. This will result in high reaction and diffusion rates, resulting in high cutting tool wear Telefon: rates. To be able to improve titanium machining, better knowledge and understanding 018 – 471 30 03 about wear during these tough conditions are needed. Telefax: 018 – 471 30 00 Wear tests were performed during orthogonal turning of titanium alloy and the cutting tool inserts were analysed by SEM, EDS and optical imaging in Alicona Hemsida: InfiniteFocus. Simulations in AdvantEdge provided calculated values for cutting http://www.teknat.uu.se/student temperatures, cutting forces and contact stresses for the same conditions as used during wear tests. It was found that turning titanium alloy with WC/Co cutting tools at cutting speeds 30-60 m/min causes chamfering of the cutting tool edge and adhesion of a build-up layer (BUL) of workpiece material on top of the rake face wear land.
    [Show full text]