Chatter Vibration in Centerless Grinding : (Research 1, Work-Rounding Mechanism under Generation of Self-Excited Vibration)

Chatter vibration in cutting processes usually leads to surface finish degradation, tool damage, cutting noise, energy loss, etc. Self-excited vibration particularly seems to be a problem that is easily increased to large vibration. The regenerative effect is considered as one of the causes of chatter vibration. Although the chatter vibration occurs in various types of processing, the end-milling is a typical process that seems to cause the chatter vibration due to a lack of rigidity of one or more parts of the machine tools, cutting tool, and work-piece. The aim of our research is to propose a simple method to control chatter vibration of the end-milling process on the basis of a coupling model integrating the related various elements. In this study, hammering tests were carried out to measure the transfer function of a machine tool and cutting tool system, which seems to cause vibration. By comparing these results, finite elemental method (FEM) analysis models were constructed. Additionally, cutting experiments were carried out to confirm the chatter vibration frequencies in end-milling with a machining center. In the hammering tests, impulse hammer and multiple acceleration pick-ups are connected to a multi-channel FFT analyzer and estimate the natural frequencies and natural vibration modes. A simplified FEM model is proposed by circular section stepped beam elements on the basis of the hammering test results, considering a coupling effect. In comparisons of the calculated results and hammering test results, the vibration modes are in good agreement. As a result, the proposed model accurately predicts the chatter vibration considering several effects among the relating elements in end-milling. Moreover, it can be seen that the chatter vibration is investigated from a viewpoint of the integrating model of the end-milling process.

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Assessment of the Cutting Tooling Effect on Turning Chatter

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.433-435.2101 ◽

2013 ◽

Vol 433-435 ◽

pp. 2101-2106

Author(s):

Joon Hwang ◽

Ey Hyoun Jeong ◽

Eui Sik Chung ◽

Steven Y. Liang

Keyword(s):

Cutting Forces ◽

Cutting Speed ◽

Tool Geometry ◽

Depth Of Cut ◽

Nonlinear Phenomenon ◽

Chatter Vibration ◽

Machining Performance ◽

Dynamic Component ◽

Excited Vibration ◽

Overhang Length

Machining performance is often limited by chatter vibration at the tool-workpiece interface. Chatter is a type of machining self-excited vibration which originates from the variation in cutting forces and the flexibility of the machine tool structure. Machining chatter is an inherently nonlinear phenomenon that is affected by many parameters such as cutting conditions, tool geometry, cutting speed, feed rate, depth of cut, overhang length of tool, clamping condition of workpiece. This study presents experimental approach for investigation of effects of various cutting tool geometry on the onset of chatter. In turning process, measured cutting force signal and triaxial accelerometer signal was used to know the characteristics of chatter vibration. The static and dynamic component of cutting forces reflect onset of chatter vibration. Proper selection of tooling is an important parameter in terms of chatter elimination in machining.

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Pengaruh Geometri Pahat Variabel Helix Angle Pada Parameter Mesin Cnc Milling Vertikal Berbasis Mikrokontroler Terhadap Nilai Getaran Chatter

JAMI: Jurnal Ahli Muda Indonesia ◽

10.46510/jami.v1i2.31 ◽

2020 ◽

Vol 1 (2) ◽

pp. 62-71

Author(s):

Festo Andre Hardinsi ◽

Oyong Novareza ◽

Achmad As’ad Sonief

Keyword(s):

Feed Rate ◽

Helix Angle ◽

Machining Process ◽

Depth Of Cut ◽

Cnc Milling ◽

Chatter Vibration ◽

Vibration Acceleration ◽

Slot Milling ◽

Excited Vibration ◽

Variable Helix

Abstrak Objektif. Getaran yang sering terjadi pada pengerjaan proses produksi menggunakan permesinan CNC milling merupakan hal yang sangat penting untuk diperhitungkan. Getaran ini dapat menyebabkan perubahan dimensi dan mempengaruhi tingkat kualitas benda kerja yang dihasilkan, sehingga efek getaran chatter atau self-excited vibration pada proses pengerjaan produksi menjadi masalah utama dalam proses permesinan milling. Nilai getaran chatter ditentukan menggunakan grafik SLD secara ekperimental untuk mengetahui batas antara chatter free dan chatter occurs. Material and Metode. Material yang digunakan dalam penelitian ini adalah Stanless steel 304, dengan menggunakan sensor MPU 6050 yang terhubung pada mikrokontroler Arduino Uno menggunakan software LabVIEW 2019 student edition yang digunakan untuk mengidentifikasi nilai acceleration getaran chatter. Besar nilai acceleration diukur menggunakan FFT menggunakan software DIAdem 2019 student. Metode yang digunakan dalam penelitian ini adalah dalam bentuk eksperimental, dengan geometri pahat Variabel Helix Angle (VHA) 2 variasi sudut yaitu 40/42 (Derajat), Spindel Speed sebesar 2000,2500,3000 (RPM) , Axial Depth Of Cut sebesar 0.5, 1.0, 1.5 (mm), dan Feed Rate sebesar 100, 125 dan 150 (mm/s). Hasil. Hasil pada Grafik Stability Lobe Diagram yang didapatkan pada proses permesinan slot milling menggunakan pahat variable helix angle 40/42 derajat dengan feed rate 150 mm/mnt memiliki chatter free yang lebih tinggi dibandingkan dengan feed rate 100 dan 125 mm/mnt. Kesimpulan. Dari hasil yang didapatkan bahwa semakin tinggi nilai feed rate maka nilai acceleration getaran chatter semakin rendah. Untuk pengembangan dalam penelitian selanjutkan maka perlu dilakukan pemilihan parameter geometri pahat dengan variasi 3 sudut mata pahat untuk mengetahui nilai getaran chatter yang signifikan. Abstrack Objective.Vibration that often occurs in the production process using CNC milling is very important to be taken into account. This is vibration can cause dimensional changes and affect the level of quality of the workpiece produced. Therefore, effect of chatter vibration or self-excited vibration on production process becomes a major problem in the milling machining process. Chatter vibration values can be determined using experimental SLD for determine boundary between free chatter and chatter occur. Materials and Methods .The material used in this study is stanless steel 304, using the MPU 6050 sensor connected to Arduino Uno mikrokontroler using LabVIEW 2019 student edition software that is used to identify chatter vibration acceleration. Acceleration is measured using FFT using 2019 student DIAdem software. The method used is experimental, geometry Variable Helix Angle 2 angular 40/42 (Degrees), Spindel Speed of 2000,2500,3000 (RPM), Axial Depth Of Cut of 0.5, 1.0, 1.5 (mm), and Feed Rate of 100, 125 and 150 (mm / s). Results. Results in the Graph Lobe Stability Diagram obtained in slot milling machining process using a variable helix angle of 40/42 degrees with feed rate of 150 mm / min have higher chatter free compared to feed rates of 100 and 125 mm / min. Conclusion. The results show that higher the value of feed rate, chatter vibration acceleration value is lower. For further development in research, it is necessary to select tool geometry parameters with variations of 3 tool eye angle to determine chatter vibration significant

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Growing Mechanism of Self-excited Chatter Vibration in Centerless Grinding and Strategies for Stabilization (1st Report)

Journal of the Japan Society of Precision Engineering ◽

10.2493/jjspe1933.49.715 ◽

1983 ◽

Vol 49 (6) ◽

pp. 715-721 ◽

Cited By ~ 1

Author(s):

Fukuo HASHIMOTO ◽

Akira KANAI ◽

Masakazu MIYASHITA ◽

Takashi MORIYA ◽

Hiroto TOBA

Keyword(s):

Chatter Vibration ◽

Centerless Grinding

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Chatter Vibration in Centerless Grinding : Research 2, Influence of Growing up Mechanism of Self-Excited Chatter Vibration upon Finishing Accuracy

Bulletin of JSME ◽

10.1299/jsme1958.15.544 ◽

1972 ◽

Vol 15 (82) ◽

pp. 544-553 ◽

Cited By ~ 4

Author(s):

Yuji FURUKAWA ◽

Masakazu MIYASHITA ◽

Susumu SHIOZAKI

Keyword(s):

Growing Up ◽

Chatter Vibration ◽

Centerless Grinding

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Chatter Vibration Comparison Between Normal Helix Angle and Variable Helix Angle in End Milling Process Based on Spectrum Analysis

Jurnal Rekayasa Mesin ◽

10.21776/ub.jrm.2020.011.03.25 ◽

2020 ◽

Vol 11 (3) ◽

pp. 531-536

Author(s):

Achmad As'ad Sonief ◽

◽

Arda Nur Fauzan ◽

Fachry Azlan ◽

Muhammad Aziz Bashori

Keyword(s):

Spectrum Analysis ◽

Cutting Tool ◽

End Milling ◽

Helix Angle ◽

Depth Of Cut ◽

Chatter Vibration ◽

Machining Processes ◽

Chatter Vibrations ◽

Excited Vibration ◽

Variable Helix

Chatter vibration in machining processes is often found in cutting processes which will decrease the machining efficiency and the surface quality of the products. Chatter is a relative vibration of the cutting tool and workpiece caused by the fluctuation of cutting force that is concerned to be a self-excited vibration. The variable Helix Angle Cutting tool which has pitch angle variation will also inflict different tooth passing frequencies on the flute that stand contiguous and trim the resonance frequency. This research aims to compare chatter vibrations that occurred between Normal Helix Angle and Variable Helix Angle cutting tool based on spectrum analysis on cutting parameter variety (depth of cut; rotation speed; feed rate milling). The outcome is spectrum analysis can detect the chatter phenomenon, measure the natural frequency (38-42 Hz), and also compare chatter vibrations between two tools appropriately.

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