An Investigation of Variable Spindle Speed Face Milling for Tool-Work Structures With Complex Dynamics, Part 2: Physical Explanation

1997 ◽  
Vol 119 (3) ◽  
pp. 273-280 ◽  
Author(s):  
R. Radulescu ◽  
S. G. Kapoor ◽  
R. E. DeVor
Keyword(s):  
Forced Vibration ◽  
Cutting Forces ◽  
Complex Dynamics ◽  
Spindle Speed ◽  
Constant Speed ◽  
Cutting Process ◽  
Variable Speed ◽  
Work System ◽  
Machining Operations ◽  
Work Done

Part 2 of this paper focuses on the explanation, both on theoretical grounds and through model simulations, of why the technique of variable spindle speed machining is an effective tool for increasing the quality and productivity of machining operations. In particular, Part 2 explains why, by disturbing the regenerative and forced vibration excitation frequencies which generate large amplitudes of vibration during constant speed machining, variable speed machining has the potential to reduce the vibration of the tool-work system and be robust with respect to the cutting process dynamics. The explanation is based on the work done by the cutting forces, the chip load variation, tool-work displacements, cutting forces, and workpiece surface error generated by both constant and variable speed machining. By investigating the effects of regeneration and forced vibration during variable speed machining on the vibration of tool-work systems having different cutter diameter-to-workpiece width ratios, it has been shown that variable speed machining is also robust with respect to the geometry of the tool-work system. This work concludes that variable speed machining is safer to use than constant speed machining when the effects of the tool-work dynamics and geometry on the vibration of the cutting process are hard to determine.

An Investigation of Variable Spindle Speed Face Milling for Tool-Work Structures With Complex Dynamics, Part 1: Simulation Results

1997 ◽  
Vol 119 (3) ◽  
pp. 266-272 ◽  
Author(s):  
R. Radulescu ◽  
S. G. Kapoor ◽  
R. E. DeVor
Keyword(s):  
Complex Dynamics ◽  
Dominant Mode ◽  
Face Milling ◽  
Constant Speed ◽  
Variable Speed ◽  
Coupled Modes ◽  
Small Surface ◽  
Work System ◽  
Modes Of Vibration ◽  
Cutting Processes

A mechanistic dynamic model is used to simulate a face milling process during constant and variable speed machining. The model can be used to predict the optimum speed trajectory that can provide a low level of vibration and consequently a large productivity rate and a small surface error. The model is used to investigate the vibration of face milling processes that have one, or multiple coupled modes of vibration acting throughout the cut. For cutting processes having one dominant mode of vibration, the model predicts that variable speed machining is especially effective over constant speed machining when the tool-work system changes its dominant mode of vibration throughout the cut, or when the tool-work system has several modes of vibration coming from component parts that are cut in the same time. For cutting processes having multiple dominant modes of vibration, the model predicts that variable speed machining is especially effective over constant speed machining when the tool-work modes of vibration are unequal and moderately coupled to each other. Also, the model suggests that for tool-work systems having complex geometries with dynamics hard to predict, variable speed machining is safer to use than constant speed machining when trying to achieve high productivity rates. This is due to the fact that variable speed machining is robust with respect to the dynamics of the tool-work system. Finally, the model predictions are in good agreement with the experiment.

Basic Mechanics of the Metal-Cutting Process

1944 ◽  
Vol 11 (3) ◽  
pp. A168-A175 ◽  
Author(s):  
M. Eugene Merchant
Keyword(s):  
High Speed ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Orthogonal Cutting ◽  
Cutting Edge ◽  
Cutting Process ◽  
Work Piece ◽  
Machining Operations ◽  
Work Done ◽  
Metal Work

Abstract The author presents a mathematical analysis of the geometry and mechanics of the metal-cutting process, covering two common types of geometry which occur in cutting. This analysis offers a key for the study of engineering problems in the field of metal cutting in terms of such fundamental quantities as strain, rate of shear, friction between chip and tool, shear strength of the metal, work done in shearing the metal and in overcoming friction, etc. The two cases covered are, in essence, that of a straight-edged cutting tool moving relative to the work-piece in a direction perpendicular to its cutting edge, termed “orthogonal cutting,” and that of a similar cutting tool so set that the cutting edge is oblique to the direction of relative motion of tool and work, termed “oblique cutting.” Equations are developed which permit the calculation of such quantities as those just enumerated from readily observable values. The theoretical findings are particularly applicable and significant in the case of present-day high-speed machining operations with sintered-carbide tools.

The Trial Research on Suppressing the Chatter by Variable Speed Milling

2011 ◽  
Vol 291-294 ◽  
pp. 2010-2013 ◽  
Author(s):  
Zhi Jian Gou
Keyword(s):  
Cutting Tool ◽  
Face Milling ◽  
Spindle Speed ◽  
Cutting Process ◽  
Variable Speed ◽  
Trajectory Parameter ◽  
Speed Variation ◽  
Cutting Chatter ◽  
Speed Parameter ◽  
Tool Cutting

The vibration occurring in cutting process is a very harmful phenomenon, which destroys the surface finish and dimensional integrity of workpieces and quickens the wear of cutting tool. Cutting chatter can be suppressed or reduced by applying the method of suppressing chatter by variable speed cutting. In order to investigate the effect of variable speed parameters and cutting conditions on suppressing the chatter in face milling, the tests have been conducted.The results have shown that cutting with variable spindle speed cutting in face milling will suppress the development of chatter. If chatter occurs in cutting process, the vibration amplitude of variable speed cutting can reduce by 3-6 times lower than that of constant speed cutting, as long as the variable speed parameter are selected suitably.The values of speed variation amplitude Δn/no and speed variation frequency fn of spindle speed trajectory parameter have great effect on suppressing chatter, Δn/no = 15- 20% and fn = 0.4 - 0.5Hz are suitable.

Predicting the High Speed Cutting Process of Titanium Alloy by Finite Element Method

2011 ◽  
Author(s):  
Xiangqin Zhang ◽  
Xueping Zhang ◽  
A. K. Srivastava
Keyword(s):  
Finite Element ◽  
Cutting Forces ◽  
High Speed ◽  
Cutting Temperature ◽  
Chip Morphology ◽  
Cutting Process ◽  
Fe Model ◽  
Dry Cutting ◽  
Friction Coefficients ◽  
Machining Conditions

To predict the cutting forces and cutting temperatures accurately in high speed dry cutting Ti-6Al-4V alloy, a Finite Element (FE) model is established based on ABAQUS. The tool-chip-work friction coefficients are calculated analytically using the measured cutting forces and chip morphology parameter obtained by conducting the orthogonal (2-D) machining tests. It reveals that the friction coefficients between tool-work are 3∼7 times larger than that between tool-chip, and the friction coefficients of tool-chip-work vary with feed rates. The analysis provides a better reference for the tool-work-chip friction coefficients than that given by literature empirically regardless of machining conditions. The FE model is capable of effectively simulating the high speed dry cutting process of Ti-6Al-4V alloy based on the modified Johnson-Cook model and tool-work-chip friction coefficients obtained analytically. The FE model is further validated in terms of predicted forces and the chip morphology. The predicted cutting force, thrust force and resultant force by the FE model agree well with the experimentally measured forces. The errors in terms of the predicted average value of chip pitch and the distance between chip valley and chip peak are smaller. The FE model further predicts the cutting temperature and residual stresses during high speed dry cutting of Ti-6Al-4V alloy. The maximum tool temperatures exist along the round tool edge, and the residual stress profiles along the machined surface are hook-shaped regardless of machining conditions.

Modelling of the Deburring Process

2006 ◽  
Vol 5-6 ◽  
pp. 367-374
Author(s):  
C. G. Dumitraş
Keyword(s):  
Central Composite Design ◽  
Cutting Force ◽  
Cutting Forces ◽  
Cutting Process ◽  
Central Composite ◽  
The Way

Due to robotic deburring development, the research gains a new orientation and focused on the cutting forces and the chip control. The present paper will emphasize the main difference which occurs between the normal cutting process and the deburring process, the way it develops and the parameters which characterize this process. Also the dynamics of the process are considered. Based on a central composite design one determine a relation between the geometry of the tool, workpiece hardness and cutting force.

Dynamic model of cutting process with modulated spindle speed

2012 ◽  
Author(s):  
R. Rusinek ◽  
K. Kecik ◽  
J. Warminski ◽  
A. Weremczuk
Keyword(s):  
Dynamic Model ◽  
Spindle Speed ◽  
Cutting Process

Characterizing the Effect of Cutting Condition, Tool Path, and Heat Treatment on Cutting Forces of Selective Laser Melting Spherical Component in Five-Axis Milling

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Amir Mahyar Khorasani ◽  
Ian Gibson ◽  
Moshe Goldberg ◽  
Guy Littlefair
Keyword(s):  
Heat Treatment ◽  
Production Process ◽  
Cutting Force ◽  
Feed Rate ◽  
Cutting Forces ◽  
Tool Path ◽  
Annealing Temperature ◽  
Spindle Speed ◽  
Cutting Condition ◽  
Scallop Height

Additive manufacturing (AM), partly due to its compatibility with computer-aided design (CAD) and fabrication of intricate shapes, is an emerging production process. Postprocessing, such as machining, is particularly necessary for metal AM due to the lack of surface quality for as-built parts being a problem when using as a production process. In this paper, a predictive model for cutting forces has been developed by using artificial neural networks (ANNs). The effect of tool path and cutting condition, including cutting speed, feed rate, machining allowance, and scallop height, on the generated force during machining of spherical components such as prosthetic acetabular shell was investigated. Also, different annealing processes like stress relieving, mill annealing and β annealing have been carried out on the samples to better understand the effect of brittleness, strength, and hardness on machining. The results of this study showed that ANN can accurately apply to model cutting force when using ball nose cutters. Scallop height has the highest impact on cutting forces followed by spindle speed, finishing allowance, heat treatment/annealing temperature, tool path, and feed rate. The results illustrate that using linear tool path and increasing annealing temperature can result in lower cutting force. Higher cutting force was observed with greater scallop height and feed rate while for higher finishing allowance, cutting forces decreased. For spindle speed, the trend of cutting force was increasing up to a critical point and then decreasing due to thermal softening.

Essence of Electric Charge of elementary particles according of New axioms and Laws

2020 ◽  
Vol 3 (4) ◽  
Keyword(s):  
Electromagnetic Field ◽  
Electron Pair ◽  
Constant Speed ◽  
Longitudinal Vortex ◽  
Uniform Motion ◽  
Variable Velocity ◽  
Variable Speed ◽  
External Observer ◽  
Closed Circle ◽  
The Waves

Two new Axioms and eight new Laws have been proposed and developed in previous reports. This report uses both axioms and only four laws. According to the first axiom (Axiom1), we can replace uniform motion in a closed circle with non-uniform motion in an open vortex. According to the second axiom (Axiom2), there are pairs of vortices that are mutually orthogonal or they tend to work in a system by a special type of resonance. Of all the variants of vortex pairs, the most probable is the pair: accelerating vortex from the center outwards connected with a delayed vortex from the periphery inwards. This pair is a model of the connected proton-electron pair. The behavior of a free electron and a proton in an Electromagnetic Field is studied. Actually like a cross vortex from outside to inside the electron will be directed to the positive pole. Therefore, an external observer who does not know what the internal structure of the electron is will think and will be deceived that the electron carries a negative charge. The exact opposite is observed for the proton. The properties of a system of linked electrons and protons are also studied. It is known that the Electromagnetic Field propagates at a constant speed and when pulsating the waves are only transverse. According to the new Axioms and Laws in the electron-proton system, the internal connections are of variable speed and when pulsating, the waves are not only transverse and longitudinal. Because the Electromagnetic field is only transverse at a constant speed , it appears that the interaction between the proton and the electron is not Electromagnetic but some other interaction. The interaction between the protons includes cross vortex with variable velocity and longitudinal vortex with variable velocity

scholarly journals Comparative Analysis of Cutting Forces, Torques, and Vibration in Drilling of Bovine, Porcine, and Artificial Femur Bone with Considerations for Robot Effector Stiffness

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Oluseyi Adewale Orelaja ◽  
Xingsong Wang ◽  
Donghua Shen ◽  
Dauda Sh. Ibrahim ◽  
Tianzheng Zhao ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Cutting Forces ◽  
Spindle Speed ◽  
Depth Of Cut ◽  
Drilling Process ◽  
Robot Arm ◽  
Drilling Force ◽  
Significant Drop ◽  
Negative Effect ◽  
Conventional Drilling

Bone drilling is known as one of the most sensitive milling processes in biomedical engineering field. Fracture behavior of this cortical bone during drilling has attracted the attention of many researchers; however, there are still impending concerns such as necrosis, tool breakage, and microcracks due to high cutting forces, torques, and high vibration while drilling. This paper presents a comparative analysis of the cutting forces, torques, and vibration resulted on different bone samples (bovine, porcine, and artificial femur) using a 6dof Robot arm effector with considerations of its stiffness effects. Experiments were conducted on two spindle speeds of 1000 and 1500 rpm with a drill bit diameter of 2.5 mm and 6 mm depth of cut. The results obtained from the specimens were processed and analyzed using MATLAB R2015b and Visio 2000 software; these results were then compared with a prior test using manual and conventional drilling methods. The results obtained show that there is a significant drop in the average values of maximum drilling force for all the bone specimens when the spindle speed changes from 1000 rev/min to 1500 rev/min, with a drop from (20.07 to 12.34 N), approximately 23.85% for bovine, (11.25 to 8.14 N) with 16.03% for porcine, and (5.62 to 3.86 N) with 33.99% for artificial femur. The maximum average values of torque also decrease from 41.2 to 24.2 N·mm (bovine), 37.0 to 21.6 N·mm (porcine), and 13.6 to 6.7 N·mm (artificial femur), respectively. At an increase in the spindle speed, the vibration amplitude on all the bone samples also increases considerably. The variation in drilling force, torque, and vibration in our result also confirm that the stiffness of the robot effector joint has negative effect on the bone precision during drilling process.

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