Experimental Investigation and Modeling of Milling Burrs

2013 ◽  
Author(s):  
Seyed Ali Niknam ◽  
Victor Songmene
Keyword(s):  
Computational Model ◽  
Material Properties ◽  
Aluminium Alloys ◽  
Cutting Parameters ◽  
Burr Formation ◽  
Force Coefficient ◽  
Slot Milling ◽  
Part Quality ◽  
Cutting Force Coefficient ◽  
Machining Operations

The burr formation is one of the most common and undesirable phenomenon occurring in machining operations which reduces assembly and machined part quality. Therefore, it is desired to eliminate the burrs or reduce the effort required to remove them. This paper presents the results of an experimental study and describe the influence of cutting parameters on slot milling burrs, namely top burrs and exit burrs. Statistical methods are also used to determine the controllability of each burr. A computational model is then proposed to predict the exit up milling side burr thickness based on cutting parameters and material properties such as yield strength and specific cutting force coefficient that are the only unknown variables in the model. The proposed computational model is validated using experimental results obtained during slot milling of 2024-T351 and 6061-T6 aluminium alloys.

Machinability study of aircraft series aluminium alloys 7075-T6 and 7050-T7451

2020 ◽  
Vol 44 (3) ◽  
pp. 427-439
Author(s):  
Ali Yeganefar ◽  
Seyed Ali Niknam ◽  
Victor Songmene
Keyword(s):  
Aluminium Alloy ◽  
Surface Quality ◽  
Aluminium Alloys ◽  
End Milling ◽  
Experimental Studies ◽  
Burr Formation ◽  
Limited Information ◽  
Milling Operations ◽  
Aluminium Alloy 7050 ◽  
Machining Operations

The aluminium alloy 7050-T7451 is generally considered as the principal choice in aeronautical applications demanding adequate strength, stress corrosion cracking resistance, and toughness. Surprisingly, despite extensive research works on machining and machinability of aluminium alloys, including aluminium alloy 7075-T6, limited information was found on machining and machinability evaluation of 7050-T7451, which belongs to a similar family as 7075-T6. To remedy the lack of knowledge determined, dry ball-end milling operations were performed with coated end milling tools on both materials. Experimental characterization and cutting force measurements were performed to measure/evaluate the cutting forces, burr formation morphology, insert performance (wear/breakage), and surface quality attributes. According to experimental studies, 7050-T7451 was found more machinable than 7075-T6. Less burr formation and better surface quality were observed on 7075-T6. Machining attributes are influenced by different experimental factors. However, other machinability attributes, including residual stress, vibration modes, as well as particle emission, must be studied under various lubrication modes and machining operations in subsequent studies. This also recalls further studies on simultaneous multiple response optimization.

scholarly journals Burr edge occupancy: edge finishing index for milling machined parts

2019 ◽  
Vol 43 (2) ◽  
pp. 248-255 ◽  
Author(s):  
Seyed Ali Niknam ◽  
Azziz Tiabi ◽  
Victor Songmene
Keyword(s):  
Aluminium Alloys ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Machining Time ◽  
Slot Milling ◽  
Burr Size ◽  
Machined Parts ◽  
Edge Finishing ◽  
Selection Of

Machining burrs are formed at all machined workpiece edges. One useful solution to decrease machining time and cost, in particular for milling parts, is to generate machined parts edges with minimum burr. This article proposes burr edge occupancy ηs as an index to evaluate deburring difficulty and, consequently, adequate selection of suitable deburring methods. Initially the sensitivity of ηs to cutting parameters must be evaluated. We investigated the main governing factors on ηs when slot milling two types of aluminium alloys (from different families) that are used in the automotive and aerospace industries. The cutting parameters that led to edges with minimum ηs are presented. It was found that, unlike most burr size attributes, ηs is sensitive to variation of the cutting parameters used: cutting speed, family of material, and cutting tools. Lower ηs means less time and effort for deburring and edge finishing of machined parts. Furthermore, ηs measurement is more convenient than the procedures used to measure other burr size attributes, including burr height (bh) and burr thickness (bt).

scholarly journals FEM and Analytical Modeling of the Incipient Chip Formation for the Generation of Micro-Features

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3789
Author(s):  
Michele Lanzetta ◽  
Marco Picchi Picchi Scardaoni ◽  
Armin Gharibi ◽  
Claudia Vivaldi
Keyword(s):  
Material Properties ◽  
Analytical Modeling ◽  
Cutting Tool ◽  
Sustainable Manufacturing ◽  
Cutting Parameters ◽  
Micro Machining ◽  
Machining Processes ◽  
Steel Alloys ◽  
Diamond Blade ◽  
Micro Features

This paper explores the modeling of incipient cutting by Abaqus, LS-Dyna, and Ansys Finite Element Methods (FEMs), by comparing also experimentally the results on different material classes, including common aluminum and steel alloys and an acetal polymer. The target application is the sustainable manufacturing of gecko adhesives by micromachining a durable mold for injection molding. The challenges posed by the mold shape include undercuts and sharp tips, which can be machined by a special diamond blade, which enters the material, forms a chip, and exits. An analytical model to predict the shape of the incipient chip and of the formed grove as a function of the material properties and of the cutting parameters is provided. The main scientific merit of the current work is to approach theoretically, numerically, and experimentally the very early phase of the cutting tool penetration for new sustainable machining and micro-machining processes.

Analysis of the effect of tool posture on stability considering the nonlinear dynamic cutting force coefficient

2021 ◽  
pp. 1-19
Author(s):  
Zepeng Li ◽  
Rong Yan ◽  
Xiaowei Tang ◽  
Fang Yu Peng ◽  
Shihao Xin ◽  
...  
Keyword(s):  
Cutting Force ◽  
Nonlinear Dynamic ◽  
Chip Thickness ◽  
Cutting Depth ◽  
Force Coefficient ◽  
Critical Cutting Depth ◽  
Dynamic Cutting Force ◽  
Cutting Force Coefficient ◽  
Tool Posture ◽  
Instantaneous Uncut Chip Thickness

Abstract In aviation and navigation, complicated parts are milled with high-speed low-feed-per-tooth milling to decrease tool vibration for high quality. Because the nonlinearity of the cutting force coefficient (CFC) is more evident with the relatively smaller instantaneous uncut chip thickness, the stable critical cutting depth and its distribution against different tool postures are affected. Considering the nonlinearity, a nonlinear dynamic CFC model that reveals the effect of the dynamic instantaneous uncut chip thickness on the dynamic cutting force is derived based on the Taylor expansion. A five-axis bull-nose end milling dynamics model is established with the nonlinear dynamic CFC model. The stable critical cutting depth distribution with respect to tool posture is analyzed. The stability results predicted with the dynamic CFC model are compared with those from the static CFC model and the constant CFC model. The effects of tool posture and feed per tooth on stable critical cutting depth were also analyzed, and the proposed model was validated by cutting experiments. The maximal stable critical cutting depths that can be achieved under different tool postures by feed per tooth adjustment were calculated, and corresponding distribution diagrams are proposed for milling parameter optimization.

scholarly journals Prediction of Nonlinear Micro-Milling Force with a Novel Minimum Uncut Chip Thickness Model

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1495
Author(s):  
Tongshun Liu ◽  
Kedong Zhang ◽  
Gang Wang ◽  
Chengdong Wang
Keyword(s):  
Cutting Force ◽  
Chip Thickness ◽  
Micro Milling ◽  
Force Model ◽  
Force Coefficient ◽  
Uncut Chip Thickness ◽  
Milling Force ◽  
Minimum Uncut Chip Thickness ◽  
Cutting Force Coefficient ◽  
Milling Force Model

The minimum uncut chip thickness (MUCT), dividing the cutting zone into the shear region and the ploughing region, has a strong nonlinear effect on the cutting force of micro-milling. Determining the MUCT value is fundamental in order to predict the micro-milling force. In this study, based on the assumption that the normal shear force and the normal ploughing force are equivalent at the MUCT point, a novel analytical MUCT model considering the comprehensive effect of shear stress, friction angle, ploughing coefficient and cutting-edge radius is constructed to determine the MUCT. Nonlinear piecewise cutting force coefficient functions with the novel MUCT as the break point are constructed to represent the distribution of the shear/ploughing force under the effect of the minimum uncut chip thickness. By integrating the cutting force coefficient function, the nonlinear micro-milling force is predicted. Theoretical analysis shows that the nonlinear cutting force coefficient function embedded with the novel MUCT is absolutely integrable, making the micro-milling force model more stable and accurate than the conventional models. Moreover, by considering different factors in the MUCT model, the proposed micro-milling force model is more flexible than the traditional models. Micro-milling experiments under different cutting conditions have verified the efficiency and improvement of the proposed micro-milling force model.

scholarly journals Finite Element Analysis and Statistical Optimization of End-Burr in Turning AA2024

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 276 ◽  
Author(s):  
Muhammad Asad ◽  
Hassan Ijaz ◽  
Waqas Saleem ◽  
Abdullah Mahfouz ◽  
Zeshan Ahmad ◽  
...  
Keyword(s):  
Finite Element ◽  
Orthogonal Cutting ◽  
Research Work ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Shear Zones ◽  
Statistical Analyses ◽  
Burr Formation ◽  
Pivot Point ◽  
Exit Edge

This contribution presents three-dimensional turning operation simulations exploiting the capabilities of finite element (FE) based software Abaqus/Explicit. Coupled temperature-displacement simulations for orthogonal cutting on an aerospace grade aluminum alloy AA2024-T351 with the conceived numerical model have been performed. Numerically computed results of cutting forces have been substantiated with the experimental data. Research work aims to contribute in comprehension of the end-burr formation process in orthogonal cutting. Multi-physical phenomena like crack propagation, evolution of shear zones (positive and negative), pivot-point appearance, thermal softening, etc., effecting burr formation for varying cutting parameters have been highlighted. Additionally, quantitative predictions of end burr lengths with foot type chip formation on the exit edge of the machined workpiece for various cutting parameters including cutting speed, feed rate, and tool rake angles have been made. Onwards, to investigate the influence of each cutting parameter on burr lengths and to find optimum values of cutting parameters statistical analyses using Taguchi’s design of experiment (DOE) technique and response surface methodology (RSM) have been performed. Investigations show that feed has a major impact, while cutting speed has the least impact in burr formation. Furthermore, it has been found that the early appearance of the pivot-point on the exit edge of the workpiece surface results in larger end-burr lengths. Results of statistical analyses have been successfully correlated with experimental findings in published literature.

A review of mechanical drilling on fiber metal laminates

2020 ◽  
pp. 002199832095774
Author(s):  
Eduardo Pires Bonhin ◽  
Sarah David-Müzel ◽  
Manoel Cléber de Sampaio Alves ◽  
Edson Cocchieri Botelho ◽  
Marcos Valério Ribeiro
Keyword(s):  
Mechanical Properties ◽  
Cutting Parameters ◽  
Burr Formation ◽  
Drilling Process ◽  
Machining Parameters ◽  
Specific Mass ◽  
Fiber Metal Laminates ◽  
Dimensional Error ◽  
Main Method ◽  
Fiber Metal

The use of fiber metal laminates (FML) in aeronautics components has been increased in the last years, mainly due to the gain in mechanical properties combined with low specific mass. However, in the assembly of these materials on the structures to which they will be attached, mechanical screwing is still the main method used, which requires the performance of drilling processes. Something it is very complicated for these materials and can cause damage that compromises the performance. Therefore, this work aims to approach and summarize the evolution of the mechanical drilling process on FML developed in the last years. By the work, the main problems that occur during the drilling of these materials are punctually approached, such as delamination, burr formation, dimensional error, poor roughness, and tool wear. In addition, it is presented how these problems are affected by the machining parameters (cutting parameters, geometry, material/coating tool, and cutting environment), as well as suggestions for minimizing process problems. Thus, the article intends to provide as much information as possible available in the literature, seeking to help researchers gain a comprehensive view of the mechanical drilling of fiber metal laminates.

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