A Study of the Impact of Workpiece Location on Machining Performance of a 2-DoF PKM Based Machine Tool

2013 ◽  
Author(s):  
A. B. Koteswara Rao ◽  
Sanjay Darvekar ◽  
K. Ramji
Keyword(s):  
Surface Roughness ◽  
End Milling ◽  
Structural Deformation ◽  
Quality Level ◽  
Machining Performance ◽  
Machined Surface ◽  
Milling Operations ◽  
Milling Operation ◽  
Tool Position ◽  
The Impact

This paper presents the impact of workpiece location on the machining performance of a 2-degree of freedom Parallel Kinematic Machine (PKM) tool. The PKM behavior is highly non-uniform and depends on the tool position within the workspace. The structural deformation and vibration due to cutting loads affect the quality of machined surfaces. The aim of the present study is to find the optimal tool position (workpiece location) where the workpiece is machined to a specific quality level. End-milling operations are carried out at various locations within the workspace and the surface roughness of machined surface (Ra) is measured at each location. A regression model is developed to predict the surface roughness. The study shows that the workpiece location has significant impact upon surface roughness of the machined part. Finally, a suitable workspace is defined for end-milling operation.

Surface Topography Predication in High-Speed End Milling of Flexible Milling System

2010 ◽  
Vol 29-32 ◽  
pp. 1832-1837
Author(s):  
Zhong Qun Li ◽  
Shuo Li ◽  
Ming Zhou
Keyword(s):  
Surface Topography ◽  
Cutting Forces ◽  
High Speed ◽  
End Milling ◽  
Cutting Parameters ◽  
Numerical Approach ◽  
Depth Of Cut ◽  
Machined Surface ◽  
Milling Operation ◽  
The Impact

During milling operation, the cutting forces will induce vibrations on both the cutting tool and the workpiece, which will affect the topography of the machined surface. Based on the Z-map representation of the workpiece, an improved model is presented to predicate the 3D surface topography along with the dynamic cutting forces during an end milling operation. A numerical approach is employed to solve the differential equations governing the dynamics of the milling system. The impact of cutting parameters such as the feedrate, the axial depth of cut and the dynamic characteristic of milling system on the surface topography is investigated by simulation. The all above can provide some instructive directions to the manufacturing engineers in determining the optimal cutting conditions of an end milling operation.

Surface Roughness Identification in End Milling Using Vibration Signals and Fuzzy Clustering

2016 ◽  
Author(s):  
Issam Abu-Mahfouz ◽  
Amit Banerjee ◽  
A. H. M. Esfakur Rahman
Keyword(s):  
Surface Roughness ◽  
Fuzzy Clustering ◽  
Wavelet Transforms ◽  
Fourier Transforms ◽  
End Milling ◽  
Cutting Conditions ◽  
Depth Of Cut ◽  
Cutting Condition ◽  
Machined Surface ◽  
Vibration Signals

The study presented involves the identification of surface roughness in Aluminum work pieces in an end milling process using fuzzy clustering of vibration signals. Vibration signals are experimentally acquired using an accelerometer for varying cutting conditions such as spindle speed, feed rate and depth of cut. Features are then extracted by processing the acquired signals in both the time and frequency domain. Techniques based on statistical parameters, Fast Fourier Transforms (FFT) and the Continuous Wavelet Transforms (CWT) are utilized for feature extraction. The surface roughness of the machined surface is also measured. In this study, fuzzy clustering is used to partition the feature sets, followed by a correlation with the experimentally obtained surface roughness measurements. The fuzzifier and the number of clusters are varied and it is found that the partitions produced by fuzzy clustering in the vibration signal feature space are related to the partitions based on cutting conditions with surface roughness as the output parameter. The results based on limited simulations are encouraging and work is underway to develop a larger framework for online cutting condition monitoring system for end milling.

scholarly journals Surface Integrity Investigation to Determine Rough Milling Effects for Assessment of Machining Allowance for Subsequent Finish Milling of Alloy 718

2021 ◽  
Vol 5 (2) ◽  
pp. 48
Author(s):  
Jonas Holmberg ◽  
Anders Wretland ◽  
Johan Berglund ◽  
Tomas Beno ◽  
Anton Milesic Karlsson
Keyword(s):  
Surface Integrity ◽  
Milling Process ◽  
Depth Of Cut ◽  
Machined Surface ◽  
Milling Operations ◽  
Milling Operation ◽  
Machining Allowance ◽  
Rough Milling

The planned material volume to be removed from a blank to create the final shape of a part is commonly referred to as allowance. Determination of machining allowance is essential and has a great impact on productivity. The objective of the present work is to use a case study to investigate how a prior rough milling operation affects the finish machined surface and, after that, to use this knowledge to design a methodology for how to assess the machining allowance for subsequent milling operations based on residual stresses. Subsequent milling operations were performed to study the final surface integrity across a milled slot. This was done by rough ceramic milling followed by finish milling in seven subsequent steps. The results show that the up-, centre and down-milling induce different stresses and impact depths. Employing the developed methodology, the depth where the directional influence of the milling process diminishes has been shown to be a suitable minimum limit for the allowance. At this depth, the plastic flow causing severe deformation is not present anymore. It was shown that the centre of the milled slot has the deepest impact depth of 500 µm, up-milling caused an intermediate impact depth of 400 µm followed by down milling with an impact depth of 300 µm. With merged envelope profiles, it was shown that the effects from rough ceramic milling are gone after 3 finish milling passes, with a total depth of cut of 150 µm.

Development of the cBN Electroplated End-Mill for High Precision Machining of CFRP

2020 ◽  
Author(s):  
Shinnosuke Yamashita ◽  
Tatsuya Furuki ◽  
Hiroyuki Kousaka ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
...  
Keyword(s):  
Surface Roughness ◽  
End Milling ◽  
Drop Out ◽  
End Mill ◽  
Machined Surface ◽  
Side Milling ◽  
Reinforced Plastics ◽  
Milled Surface ◽  
Grinding Conditions ◽  
Grinding Tool

Abstract Recently, the demand of carbon fiber reinforced plastics (CFRP) has been rapidly increased in various fields. In most cases, CFRP products requires a finish machining like cutting or grinding. In the case of an end-milling, burrs and uncut fibers are easy to occur. On the other hand, a precise machined surface and edge will be able to obtain by using the grinding tool. Therefore, this research has been developed a novel the cBN electroplated end-mill that combined end-mill and grinding tool. In this report, the effectiveness of developed tool was investigated. First, the developed tool cut the CFRP with side milling. As the result, the cBN abrasives that were fixed on the outer surface of developed tool did not drop out. Next, the end-milled surface of CFRP was ground with the developed tool under several grinding conditions based on the Design of Experiment. Consequently, the optimum grinding condition that can obtain the sharp edge which does not have burrs and uncut fibers was found. However, surface roughness was not good enough. Thus, an oscillating grinding was applied. In addition, the theoretical surface roughness formula in case using the developed tool was formularized. As the result, the required surface roughness in the airplane field was obtained.

scholarly journals Influence of Chatter of VMC Arising During End Milling Operation and Cutting Conditions on Quality of Machined Surface

1970 ◽  
Vol 2 (1) ◽  
Author(s):  
A.K.M.N. Amin, M.A. Rizal, and M. Razman
Keyword(s):  
Surface Roughness ◽  
Metal Cutting ◽  
Metal Removal ◽  
End Milling ◽  
Cutting Speed ◽  
Cutting Conditions ◽  
End Mill ◽  
Machined Surface ◽  
Operating Cycle ◽  
Wide Range

Machine tool chatter is a dynamic instability of the cutting process. Chatter results in poor part surface finish, damaged cutting tool, and an irritating and unacceptable noise. Exten¬sive research has been undertaken to study the mechanisms of chatter formation. Efforts have been also made to prevent the occurrence of chatter vibration. Even though some progress have been made, fundamental studies on the mechanics of metal cutting are necessary to achieve chatter free operation of CNC machine tools to maintain their smooth operating cycle. The same is also true for Vertical Machining Centres (VMC), which operate at high cutting speeds and are capable of offering high metal removal rates. The present work deals with the effect of work materials, cutting conditions and diameter of end mill cutters on the frequency-amplitude characteristics of chatter and on machined surface roughness. Vibration data were recorded using an experimental rig consisting of KISTLER 3-component dynamometer model 9257B, amplifier, scope meters and a PC.  Three different types of vibrations were observed. The first type was a low frequency vibration, associated with the interrupted nature of end mill operation. The second type of vibration was associated with the instability of the chip formation process and the third type was due to chatter. The frequency of the last type remained practically unchanged over a wide range of cutting speed.  It was further observed that chip-tool contact processes had considerable effect on the roughness of the machined surface.Key Words: Chatter, Cutting Conditions, Stable Cutting, Surface Roughness.

scholarly journals Experimental Investigation of MQL Optimum Parameters in End Milling of AA6061-T6 using Taguchi Method

2018 ◽  
Vol 7 (4.35) ◽  
pp. 186 ◽  
Author(s):  
W. Safiei ◽  
M.M. Rahman ◽  
S.A. Rusdan
Keyword(s):  
Surface Roughness ◽  
Flow Rate ◽  
Prediction Interval ◽  
End Milling ◽  
Green Manufacturing ◽  
Work Piece ◽  
Base Line ◽  
Machining Performance ◽  
Optimum Parameters ◽  
Mql System

Minimum Quantity Lubricants is a technique in supplying small quantity of lubricant into machining area which also part of green manufacturing approach that receive wide attention globally. The main driven of introducing MQL method was due to negative environmental impact which leads to safety and health issues of conventional coolant among workers especially in tool and mould industries. Besides, based on research findings, the MQL system has the capability for lubricating and cooling both work piece and cutting tool. In order to find the best solution for machining and also to enhance machining performance, first and foremost the MQL parameters must be controlled wisely as it has remarkable effects on lubricant coverage, droplets size and subsequently influence the machining performance. Nozzle angle, nozzle distance and MQL flow rate are the important parameters studied and surface roughness is the response parameter. Therefore, in this study, MQL optimum parameters were explored by minimizing surface roughness in end milling process using Taguchi L9 orthogonal method. Aluminum Alloy 6061-T6 was selected as work piece material. The results show that the best combination of MQL parameters in minimizing surface roughness was obtained at 30mm nozzle distance, 30 degree nozzle angle and 1.98 mL/min MQL flow rate. Hence, based on this optimal condition, three confirmation runs were conducted. The margin error is acceptable which less than 10% and within prediction interval. This results can work as a base line guidance for any experimental that employ MQL system.

An Approach to Improve Cutting Performance in Micromilling of Titanium Alloy

2020 ◽  
Vol 8 (2) ◽  
Author(s):  
Yunn-Shiuan Liao ◽  
Tsung-Hsien Li ◽  
Yi-Chen Liu
Keyword(s):  
Carbon Dioxide ◽  
Surface Roughness ◽  
Titanium Alloy ◽  
Flank Wear ◽  
End Milling ◽  
Cutting Speed ◽  
Liquid Carbon ◽  
Dry Cutting ◽  
Machined Surface ◽  
Liquid Carbon Dioxide

Abstract Application of liquid carbon dioxide to improve cutting performance in micro-end milling of Ti-6Al-4V titanium alloy was proposed in this study. It was found that the machined roughness decreased with the cutting speed as observed in the conventional cutting, when a 0.5 mm diameter end milling cutter was used in dry cutting. But, the tiny and shattered chips produced by the use of 0.3 mm diameter cutter could adhere on the machined surface and deteriorate surface finish, if the cutting speed was higher than 40 m/min. Cutting temperature was effectively decreased by applying liquid carbon dioxide during micromilling, which in turn reduced the amount of chips adhering on the machined surface and lowered flank wear. The surface roughness Ra at a cutting speed of 70 m/min was improved from 0.09 μm under dry cutting to 0.04 μm under the liquid carbon dioxide assisted cutting condition. And there were no flank wear and very few burrs left on the machined surface for the condition used in the experiment. The height of the burrs was only 25% of that under dry cutting. More, minimum quantity lubrication (MQL) was proposed to be applied together with the liquid carbon dioxide to enhance lubrication effect. It was noted that the machined surface roughness was further decreased by 15% as compared with that when the liquid carbon dioxide was applied alone. The height of burrs was reduced from 32 μm to 16 μm.

Effects of cutter path orientations on milling force, temperature, and surface integrity when ball end milling of TC17 alloy

2020 ◽  
pp. 095440542097107
Author(s):  
Xuehong Shen ◽  
Dinghua Zhang ◽  
Liang Tan
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Surface Topography ◽  
Surface Integrity ◽  
End Milling ◽  
Layer Depth ◽  
Milling Force ◽  
Mechanical Coupling ◽  
Cutter Path ◽  
The Impact

To explore the effects of cutter path orientations on milling force, temperature, and surface integrity, end ball milling experiments of TC17 titanium alloy were accomplished derived from different cutter path orientations. The experiment results of milling force and temperature were obtained. Combining with the thermo-mechanical coupling, this paper analyzes the impact of the cutter path orientations on the surface roughness, surface topography, in-depth residual stress, microhardness distributions, and microstructure. The results indicate that the maximum milling force is 224.24 N and the temperature is 672°C under vertical downward milling path, while horizontal downward orientation provides the lowest cutting force of 81.12 N and temperature of 493°C. The surface topography of the four cutter path orientations is basin-like shape, and the minimum surface roughness of 1.128 µm is achieved under vertical upward mode. Moreover, the maximum compressive residual stress of −491.8 MPa and the maximum residual stress layer depth of 45 µm are acquired under vertical downward milling. The maximum microhardness can arrive at 390 HV0.025 under the vertical path. Additionally, the transformation of the material microstructure remains elongated, bent, and fractured. The maximum plastic deformation layer depth is 44 µm under vertical downward milling path.

ANALYSIS OF THE CORRELATION BETWEEN FRACTAL STRUCTURE OF CUTTING FORCE SIGNAL AND SURFACE ROUGHNESS OF MACHINED WORKPIECE IN END MILLING OPERATION

Fractals ◽  
2019 ◽  
Vol 27 (02) ◽  
pp. 1950013 ◽  
Author(s):  
AHMAD THUFFAIL THASTHAKEER ◽  
ALI AKHAVAN FARID ◽  
CHANG TECK SENG ◽  
HAMIDREZA NAMAZI
Keyword(s):  
Surface Roughness ◽  
Cutting Force ◽  
Surface Quality ◽  
Cutting Forces ◽  
End Milling ◽  
Complex Structure ◽  
Machined Surface ◽  
End Mills ◽  
Machining Operations

Analysis of the machined surface is one of the major issues in machining operations. On the other hand, investigating about the variations of cutting forces in machining operation has great importance. Since variations of cutting forces affect the surface quality of machined workpiece, therefore, analysis of the correlation between cutting forces and surface roughness of machined workpiece is very important. In this paper, we employ fractal analysis in order to investigate about the complex structure of cutting forces and relate them to the surface quality of machined workpiece. The experiments have been conducted in different conditions that were selected based on cutting depths, type of cutting tool (serrated versus. square end mills) and machining conditions (wet and dry machining). The result of analysis showed that among all comparisons, we could only see the correlation between complex structure of cutting force and the surface roughness of machined workpiece in case of using serrated end mill in wet machining condition. The employed methodology in this research can be widely applied to other types of machining operations to analyze the effect of variations of different parameters on variability of cutting forces and surface roughness of machined workpiece and then investigate about their correlation.

Sign in / Sign up

Export Citation Format

Share Document