scholarly journals Influence of the Cut Axial Depth on Surface Roughness at High-Speed Milling of Thin-Walled Workpieces

2021 ◽  
Vol 20 (2) ◽  
pp. 127-131
Author(s):  
A. I. Germashev ◽  
V. A. Logominov ◽  
S. I. Dyadya ◽  
Y. V. Kozlova ◽  
V. A. Krishtal
Keyword(s):  
High Speed ◽  
End Milling ◽  
Spindle Speed ◽  
Depth Of Cut ◽  
Work Piece ◽  
Natural Vibration Frequency ◽  
High Speed Milling ◽  
Wide Range ◽  
Thin Walled ◽  
Axial Depth

The paper presents the results of research on the dynamics of end milling of thin-walled work-pieces having complex geometric shapes. Since the milling process with shallow depths of cut is characterized by high intermittent cutting, the proportion of regenerative vibrations decreases, and the effect of forced vibrations on the dynamics of the process, on the contrary, increases. The influence of  axial depth of cut on the vibrations arising during processing, and roughness of the processed surface have been studied in paper.  The experiments have been carried out in a wide range of changes in the spindle speed at different axial cutting depths.  Vibrations of a thin-walled work-piece  have been recorded with an inductive sensor and recorded in digital form. Then an oscillogram has been used to estimate the amplitude and frequency of oscillations. The profilograms of the machined surface have been analysed. Roughness has been evaluated by the parameter Ra. The results have shown similar relationships for each of the investigated axial cutting depths. The worst cutting conditions  have been observed when the natural vibration frequency coincided with the tooth frequency or its harmonics. It is shown that the main cause of vibrations in high-speed milling  is forced rather than regenerative vibrations. Increasing the axial depth of cut at the same spindle speed increases the vibration amplitude. However, this does not significantly affect the roughness of the processed surface in cases when it comes to vibration-resistant processing.

scholarly journals Effects of machining system parameters and dynamics on quality of high-speed milling

2013 ◽  
Author(s):  
◽  
Khaled A. M. Adem
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
End Milling ◽  
Milling Process ◽  
Depth Of Cut ◽  
Force Model ◽  
Cutting Force Coefficients ◽  
High Speed Milling ◽  
End Milling Process ◽  
Axial Depth

This dissertation outlines research on studying the effects of machining parameters such that cutting speed, feed rate, axial depth of cut, radial depth of cut and helix angle on system dynamic stability and the surface quality of high-speed milling. With the use of structural tool modal parameters, the material cutting force coefficients and the axial depth of cut, the system can avoid the chatter phenomenon of the tool at high cutting speeds. The surface roughness finish in the milling process is determined by the machining parameters and tool structure dynamics. To perform high-speed milling, the chance of tool vibration (chatter phenomenon) which affects the cutting tool, must be minimized or eliminated. In this research, the linear and nonlinear mathematical force models including the effect of the helix angle are presented for an end-milling process. The linear force model includes cutting-edge coefficients. The cutting force coefficients are determined for an end-milling process using two methods, the average force method and the optimization technique method. The second method is developed to identify the cutting force coefficients in the milling process by forming the objective functions using the optimization technique to minimize the error between the experimental and the analytical forces. Moreover, this method produced a good force model that approximates the experimental force results, which compared with the average force method. The stability lobe diagrams are created using the analytical method to determine whether the cut is stable or unstable. In addition, simulations are performed to predict stability of the milling process. By comparing simulated and experimental results, the dynamics and stability of the milling operation can be easily identified before performing any cutting operation. The slot milling experiments show that while the system in the chatter region close to the stability limits and the axial depth of cut increased, the system changes from stable chatter to chaotic chatter. Furthermore, the nature of bifurcation in milling is investigated by performing experiments and simulations. The linear and nonlinear mathematical force models are used for simulating end-milling process. Simulated bifurcation diagrams are generated using both models and compared to experimental results. In addition, the effect of the feed rate on the location of the bifurcation point (start and end of bifurcation) is studied. By comparing simulated and experimental results, the simulation using a nonlinear force model is found more accurate in predicting the dynamics and stability of the milling operation. The applications of Taguchi and response surface methodologies (RSM) are used to minimize the surface roughness in the end milling process. Taguchi’s method for optimum selection of the milling process parameters is applied based on the signal to noise ratio and ANOVA analysis of the surface finish. A second-order model contains quadratic terms that have been created between the cutting parameters and surface roughness using response surface methodology (RSM). Surface roughness of the machined surfaces are measured and used to identify the optimum levels of the milling parameters. Based on Taguchi, ANOVA, and RSM analyses, the end milling process can be optimized to improve surface finish quality and machining productivity.

Investigation of Surface Roughness and Material Removal Rate for High Speed Micro End Milling on PMMA

2015 ◽  
Vol 1115 ◽  
pp. 12-15
Author(s):  
Nur Atiqah ◽  
Mohammad Yeakub Ali ◽  
Abdul Rahman Mohamed ◽  
Md. Sazzad Hossein Chowdhury
Keyword(s):  
Surface Roughness ◽  
Material Removal Rate ◽  
Feed Rate ◽  
Material Removal ◽  
High Speed ◽  
End Milling ◽  
Removal Rate ◽  
Spindle Speed ◽  
Depth Of Cut ◽  
Micro End Milling

Micro end milling is one of the most important micromachining process and widely used for producing miniaturized components with high accuracy and surface finish. This paper present the influence of three micro end milling process parameters; spindle speed, feed rate, and depth of cut on surface roughness (Ra) and material removal rate (MRR). The machining was performed using multi-process micro machine tools (DT-110 Mikrotools Inc., Singapore) with poly methyl methacrylate (PMMA) as the workpiece and tungsten carbide as its tool. To develop the mathematical model for the responses in high speed micro end milling machining, Taguchi design has been used to design the experiment by using the orthogonal array of three levels L18 (21×37). The developed models were used for multiple response optimizations by desirability function approach to obtain minimum Ra and maximum MRR. The optimized values of Ra and MRR were 128.24 nm, and 0.0463 mg/min, respectively obtained at spindle speed of 30000 rpm, feed rate of 2.65 mm/min, and depth of cut of 40 μm. The analysis of variance revealed that spindle speeds are the most influential parameters on Ra. The optimization of MRR is mostly influence by feed rate. Keywords:Micromilling,surfaceroughness,MRR,PMMA

Cutting Forces and Surface Roughness in High-Speed End Milling of Ti6Al4V

2013 ◽  
Vol 589-590 ◽  
pp. 76-81
Author(s):  
Fu Zeng Wang ◽  
Jun Zhao ◽  
An Hai Li ◽  
Jia Bang Zhao
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Cutting Forces ◽  
High Speed ◽  
End Milling ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
Wide Range ◽  
Radial Depth ◽  
Coated Carbide

In this paper, high speed milling experiments on Ti6Al4V were conducted with coated carbide inserts under a wide range of cutting conditions. The effects of cutting speed, feed rate and radial depth of cut on the cutting forces, chip morphologies as well as surface roughness were investigated. The results indicated that the cutting speed 200m/min could be considered as a critical value at which both relatively low cutting forces and good surface quality can be obtained at the same time. When the cutting speed exceeds 200m/min, the cutting forces increase rapidly and the surface quality degrades. There exist obvious correlations between cutting forces and surface roughness.

Tool Vibration due to High Speed Micro End Milling Parameters

2013 ◽  
Vol 372 ◽  
pp. 364-368 ◽  
Author(s):  
Abdul Rahman Mohamed ◽  
Nur Atiqah ◽  
Mohammad Yeakub Ali ◽  
M.S.H. Chowdhury
Keyword(s):  
High Speed ◽  
End Milling ◽  
Signal To Noise Ratio ◽  
Cutting Parameters ◽  
Spindle Speed ◽  
Depth Of Cut ◽  
Signal To Noise ◽  
Tool Vibration ◽  
Milling Parameters ◽  
Micro End Milling

This paper presents the effect of high speed micro end milling parameters on tool vibration during machining of poly (methyl methacrylate) (PMMA). The main focus is to achieve minimum tool vibration by controlling the cutting parameters; spindle speed, feed rate and depth of cut. An empirical model for tool vibration has been developed using Taguchi method. The orthogonal array, signal-to-noise ratio and analysis of variance revealed that high spindle speed is the most influential parameter to increase the level of tool vibration.

Avoiding Instability on the Milling of Parts with Thin Features

2006 ◽  
Vol 526 ◽  
pp. 37-42 ◽  
Author(s):  
Francisco Javier Campa ◽  
Luis Norberto López de Lacalle ◽  
S. Herranz ◽  
Aitzol Lamikiz ◽  
A. Rivero
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Spindle Speed ◽  
Depth Of Cut ◽  
Test Device ◽  
High Speed Milling ◽  
Thin Walls ◽  
Chatter Vibrations ◽  
The Stability ◽  
Selection Of

In this paper, a 3D dynamic model for the prediction of the stability lobes of high speed milling is presented, considering the combined flexibility of both tool and workpiece. The main aim is to avoid chatter vibrations on the finish milling of aeronautical parts, which include thin walls and thin floors. In this way the use of complex fixtures is eliminated. Hence, an accurate selection of both axial depth of cut and spindle speed can be accomplished. The model has been validated by means of a test device that simulates the behaviour of a thin floor.

Turning Dynamics: Part 2 — Stability at High Speed

2012 ◽  
Author(s):  
Eric B. Halfmann ◽  
C. Steve Suh ◽  
N. P. Hung
Keyword(s):  
Natural Frequency ◽  
Vibration Amplitude ◽  
High Speed ◽  
Stability Limit ◽  
Stability Diagram ◽  
Spindle Speed ◽  
Depth Of Cut ◽  
Work Piece ◽  
Highly Nonlinear ◽  
Cutting Model

A comprehensive 3D lathe cutting model is validated by comparing numerical simulations to the experimental data obtained in Part 1 using instantaneous frequency. Comparison of chatter-free cutting demonstrates that the model effectively captures the work-piece natural frequency, tool natural frequency, a nonlinear mode, and the spindle speed, which are main components of the underlying dynamics observed experimentally. The model accurately simulates chatter vibrations characterized as increased vibration amplitude and the appearance of coupled tool – work-piece vibrations at a chatter frequency. The stability diagram constructed by running the model at various spindle speeds and depth-of-cuts demonstrates a general increase in the chatter-free critical depth-of-cut as the spindle speed increased. This chatter-free limit begins to exponentially level out as the spindle speed exceeds 1500RPM. At high spindle speeds the work-piece motions dominate the cutting dynamics, resulting in cases of excessive work-piece vibration amplitude and highly nonlinear frequencies which affect the efficiency of the process. The excessive work-piece amplitude cases create a second stability limit to be considered as a result of imbalance and configuration of the work-piece. Thus, work-piece dynamics should not be neglected in mathematical and experimental analyses for the design of machine tools and robust cutting control law.

Surface Residual Stress Gradient Distribution in High Speed Milling of H13 Die Steel

2009 ◽  
Vol 626-627 ◽  
pp. 183-188 ◽  
Author(s):  
Yue En Li ◽  
Jun Zhao ◽  
Cao Qing Yan ◽  
W. Wang ◽  
Shi Guo Han
Keyword(s):  
Residual Stress ◽  
High Speed ◽  
End Milling ◽  
Stress Gradient ◽  
Work Piece ◽  
High Speed Milling ◽  
Gradient Distribution ◽  
Die Steel ◽  
Feed Direction ◽  
H13 Die Steel

High speed milling experiments are performed for hardened H13 die steel by using coated ball end milling cutter, the residual stress of the work-piece surface on the feed and cross feed direction are measured, and the distribution characteristics of residual stress is analyzed. The result shows that the residual stress presents gradient distribution on feed direction, and furthermore, the three-dimensional surface micro topography has no close relation with the residual stress. In addition, the cumulative effect is discussed for explaining the phenomena.

3D Numerical Investigation of Effect of Milling Process Parameters on High Speed Milling of Ti-Al6-V4

2012 ◽  
Author(s):  
J. Ma ◽  
Shuting Lei ◽  
Huaqi Lu
Keyword(s):  
Titanium Alloy ◽  
Titanium Alloys ◽  
Numerical Investigation ◽  
Process Parameters ◽  
High Speed ◽  
Chemical Reactivity ◽  
Milling Process ◽  
Depth Of Cut ◽  
High Speed Milling ◽  
Axial Depth

Titanium alloys are widely used in aerospace industry owing to excellent mechanical properties. While because of high chemical reactivity and low thermal conductivity, titanium alloys are classified as hard-to-cut materials. In this paper, Finite Element Method (FEM) is employed to conduct numerical investigation in the effects of milling process parameters (milling speeds, feed per tooth, and axial depth of cut) on three-dimensional (3D) high speed milling of Titanium alloy (Ti-6Al-4V). The tool material used is Carbide and Johnson-Cook plastic model is employed to model the workpiece due to its capability of modeling large strains, high strain rates, and temperature dependent visco-plasticity. Different milling speeds, feed per tooth, and axial depth of cut are used to explore the effects of the milling process parameters on the cutting temperature, cutting forces, and power required for machining. This model provides fundamental understanding of cutting mechanics of the 3D high speed milling of Titanium alloy (Ti-6Al-4V).

Side-Wall Surface Quality Assessment for Micro-End Milling

2009 ◽  
Author(s):  
Jeong Hoon Ko ◽  
Kah Chuan Shaw ◽  
Irving P. Girsang ◽  
Vinay Ravi ◽  
Jaspreet S. Dhupia
Keyword(s):  
Surface Quality ◽  
End Milling ◽  
Side Wall ◽  
Spindle Speed ◽  
Cutting Conditions ◽  
Depth Of Cut ◽  
Form Error ◽  
Burr Height ◽  
Micro End Milling ◽  
Axial Depth

Mechanical micro-end milling helps in creating complex three dimensional structures without a restriction on work-piece material. So far, the surface quality assessment achieved in mechanical micro-end milling has mainly focused on the bottom milled surface of the machined part. In this paper, surface quality of the side-wall created by mechanical micro-end milling on stainless steel (SUS 304) and aluminum alloy (Al 6061) is studied. The surface quality thus achieved is assessed by considering three surface assessment factors namely average surface roughness, form error and burr height under various cutting conditions. The cutting parameters varied for machining were spindle speed, feed/tooth, radial depth of cut, and axial depth of cut. The optimal cutting conditions were evaluated for the three surface evaluation factors according to the material and cutting conditions. The surface roughness values were found to have a turning point at a particular spindle speed for both the materials and were affected by spindle speed, feed/tooth and axial depth of cut. The form error was observed to be lesser for higher axial depth of cut due to an increase in the relative tool stiffness. The burr formation was influenced mainly by feed/tooth with an increase in burr height due to the plowing effect at lowest feed rate and pushed uncut chip at highest feed rate.

Surface Quality of High Speed Milling of Silicon Carbide by Using Diamond Coated Tool

2013 ◽  
Vol 446-447 ◽  
pp. 275-278 ◽  
Author(s):  
Mohammad Iqbal ◽  
Mohamed Konneh ◽  
Ahmad Yasir Bin Md Said ◽  
Azri Fadhlan Bin Mohd Zaini
Keyword(s):  
Surface Roughness ◽  
Silicon Carbide ◽  
High Speed ◽  
Cutting Parameters ◽  
Machining Process ◽  
Depth Of Cut ◽  
Work Piece ◽  
Model Interaction ◽  
High Speed Milling ◽  
Coated Tool

The high speed milling of silicon carbide was discussed by using flat end-mill 2 mm in diameter diamond coated tool. Ultra-precision high speed spindle attachment was used to achieve cutting tool rotation speed as high as 50,000 rpm. Special fixture was designed to minimize the chatter on work-piece surface during the machining process. Three cutting parameters were selected as independent variables of the experiments. They were spindle speed, depth of cut and feed rate. The arithmetic mean value of roughness (Ra) was measured on the work-piece surface as the response of the experiment. Result of the experiment shows that the value of surface roughness can be achieved as low as 0.150 μm. Statistical analysis was provided to study the significant of the model, interaction among the cutting parameters and their effects to the surface roughness value.

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