Modelling, Simulation and Experimental validation of Burr size in Drilling of Aluminium 6061 alloy

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Procedia Manufacturing 00 (2017) 000–000 Procedia Manufacturing 20 (2018) 458–463 Procedia Manufacturing 00 (2017) 000–000 Procedia Manufacturing 00 (2017) 000–000

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

2nd International Conference on Materials Manufacturing and Design Engineering

Modelling, Simulation andonExperimental validation ofEngineering Burr size in 2nd International Conference Materials Manufacturing and Design Manufacturing Engineering Society International Conference 2017, MESIC 2017, 28-30 June Drilling ofVigo Aluminium (Pontevedra),6061 Spain alloy Modelling, Simulation2017, and Experimental validation of Burr size in 1 2 *Reddy Sreenivasulu , Chalamalasetti Drilling of Aluminium 6061 alloy 4.0: Trade-off Costing models for capacity optimization inSrinivasaRao Industry , R.V.R. & J.C.College of Engineering (Autonomous) Guntur, Andhra Pradesh, India between used capacity and, Chowdavaram, operational efficiency *Reddy Sreenivasulu1, Chalamalasetti SrinivasaRao 2 1

2

University College of Engineering, (Autonomous), Andhra University, Visakhapatnam, Andhra Pradesh, India 1

Abstract

A. Santanaa, P. Afonsoa,*, A. Zaninb, R. Wernkeb

, R.V.R. & J.C.College of Engineering (Autonomous) , Chowdavaram, Guntur, Andhra Pradesh, India 2 a University College of Engineering, (Autonomous), Andhra University, Andhra Pradesh, India University of Minho, 4800-058 Guimarães,Visakhapatnam, Portugal b

Unochapecó, 89809-000 Chapecó, SC, Brazil

Precision manufacturing gained much importance in manufacturing industries in the recent past. Drilling process takes place in all manufacturing processes and influences the acceptability of the products, as the drilling is at the most final processing stage in Abstract the production line. The burr, which is a plastically deformed material, generated during drilling is an unnecessary output and The modelindustries works through energy balance equation often lowers the surface quality, reduces the product Precision manufacturing gained much importance in life. manufacturing in thean recent past. Drilling processwhich takesfinds placethe in Abstract point at which theprocesses downward forcethe of acceptability the drill is equivalent to theasforce requiredis to plastically deform the remaining all manufacturing andcutting influences of the products, the drilling at the most final processing stage in material underneath the drill into a burr. Eliminationdeformed of burrs during drilling is a trivial task however, proper selection of the production line. The which is a plastically material, generated during is an with unnecessary output and Under the concept of burr, "Industry 4.0", production processes will be pushed todrilling be increasingly interconnected, process parameters, it can be minimized. The present work aims atworks developing a an mathematical model for burr formation in The model through energy balance equation which finds the often lowers the surface quality, reduces the product life. information basedThereby on a real time basis and, necessarily, much more efficient. In this different context, process capacityparameters. optimization drilling operation. validating these models, experiments are conducted by varying The point at which the downward cutting force of the drill is equivalent to the force required to plastically deform the remaining TM goes beyond thefrom traditional aimaofburr. capacity maximization, contributing also and value. -3D. profitability values obtained experimentation are compared with results developed inorganization’s Deform material underneath the drill into Elimination of simulated burrs during drilling is a for trivial task however, with proper selection of Indeed, lean management and continuous improvement approaches suggest capacity optimization instead of process parameters, it can be minimized. The present work aims at developing a mathematical model for burr formation in © 2018 The Authors. Published by Elsevier B.V. TM Keywords: BurrThe formation, force, Taguchi Method, experiments FEA, -3D software maximization. studyThrust of capacity optimization andDeform costing models is an research topicparameters. that deserves drilling operation. Thereby validating these models, conducted by important varyingondifferent process The Peer-review under responsibility of the scientific committee of the 2ndare International Conference Materials Manufacturing and _____________________________________________________________________________________________ values obtained from both experimentation areand compared with simulated resultsThis developed DeformTM contributions from the practical theoretical perspectives. paper in presents and-3D. discusses a mathematical Design Engineering.

model for capacity management based on different costing models (ABC and TDABC). A generic model has been TM Keywords: Burritformation, force, Taguchi Method, FEA, Deform software towards the maximization of organization’s 1. Introduction developed and was usedThrust to analyze idle capacity and to design-3D strategies _____________________________________________________________________________________________ value. The trade-off capacityofmaximization vs operational efficiency is highlighted and[1]. it is shown capacity Nowadays, 3D modelling the metal cutting processes is a more popular technique The main that advantage of optimization might hide operational inefficiency. this technique is reduction in cost and time to predict parameters such as stresses, strain rates, thrust and temperature 1.2017 Introduction © The Authors. Published by Elsevier B.V. Peer-review under of the committee of the Manufacturing Engineering Society Conferenceof Nomenclature Nowadays, 3Dresponsibility modelling of thescientific metal cutting processes is a more popular technique [1].International The main advantage 2017. this technique is reduction in cost and time to predict parameters such as stresses, strain rates, thrust and temperature

Fthrust

Drill thrust force

Keywords: Cost Nomenclature BurrModels; heightABC; TDABC; Capacity Management; Idle Capacity; Operational Efficiency B h

Cutting force of the drill FZ F Drill υ thrust Rakethrust angle force Introduction B1. Burr height h __________ F Cutting force of the drill Z *Reddy Sreenivasulu, Tel:+91 9441069440 cost of idle capacity is a fundamental information for companies and their management of extreme importance υE-The Rake angle Mail: [email protected] in modern production systems. In general, it is defined as unused capacity or production potential and can be measured __________ in several ways: tons of production, available hours of manufacturing, etc. The management of the idle capacity 2351-9789© 2017 TheTel:+91 Authors.9441069440 Published by Elsevier B.V. *Reddy Sreenivasulu, * Paulo Afonso. Tel.: +351 253 510of 761; +351 253 604 741 of the 2nd International Conference on Materials Manufacturing and Peer-review under responsibility thefax: scientific committee E- Mail: [email protected] E-mail address: [email protected] Design Engineering.

2351-9789© 2017 The Authors. Published by Elsevier B.V. 2351-9789 © 2017 The Authors. Published by Elsevier B.V. Peer-reviewunder under responsibility ofscientific the scientific committee of the 2nd International Conference on Materials Manufacturing and Peer-review of the the Manufacturing Engineering Society International Conference 2017. 2351-9789 © 2018responsibility The Authors. Published bycommittee Elsevier of B.V. Design Engineering. Peer-review under responsibility of the scientific committee of the 2nd International Conference on Materials Manufacturing and Design Engineering. 10.1016/j.promfg.2018.02.067

2

δ β μ φ y1

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Helix angle Half of the point angle drill friction angle Shear plane angle initiation height

were very difficult to found experimentally[2,3]. Especially, 3D finite element analysis show a significant advantage compared to other approaches to predict burr geometry [4] during metal cutting process. Present work carried out to accentuate the importance of 3D modelling of the drilling processes and to demonstrate its advantages. [5, 6] presented an overview of a two dimensional FEM code used by DEFORM to study orthogonal cutting. They detail many of the topics discussed in this paper but applied in two dimensions. His analysis is also applied toward orthogonal cutting as opposed to three dimensional drilling. Klocke et al. detail much of the basic FEM theory and machining theory embedded in DEFORM‘s code. One key advantage of then Lagrangian mesh in simulating drilling processes is the ability to know the entire time history of the key variables at every point during the simulation. That means, if a simulation crashes for any reason, a new simulation can start where the crashed simulation stopped. This is particularly useful because nearly every simulation has some sort of problem during the run. This is possible because the Lagrangian mesh is reformulated at nearly every time step, in order to manage the deformation of the material. One of the biggest strengths of DEFORM is its ability to mesh complex geometries. Significant deformation occurs in machining simulations and this has been historically problematic for the Lagrangian mesh. However, if the geometry is remeshed after each time step, the Lagrangian mesh is a reasonable choice to show burr formation. DEFORM is a leader in creating adaptive meshes and remeshing complex geometry and this makes it a desirable code for drilling analysis. One of the biggest strengths of DEFORM is its ability to mesh complex geometries. Significant deformation occurs in machining simulations and this has been historically problematic for the Lagrangian mesh. However, if the geometry is remeshed after each time step, the Lagrangian mesh is a reasonable choice to show burr formation. DEFORM [7] is a leader in creating adaptive meshes and remeshing complex geometry and this makes it a desirable code for drilling analysis. 2. Modeling and Simulation 2.1 Analytical Modeling Burr formation model (Fig.1) originally depends on the stress and strain rate of the material flow at the end of the cut has to be analyzed in the finite element method. The finite element analysis (FEA) is effective to understand the material behavior in the process [8, 9, 10]. However, it has not yet been applied to the design of the drill geometry and takes a long time for the simulations. Other analytical models, therefore, is required to optimize the geometry in the drilling operation. An analytical model is developed by integrating by John-Cook coupled and Sofrona‘s model to predict the thrust force and burr height in drilling process. From dimensions of geometry of twist drill ‗q‘ value obtained, after that using metal cutting principles and theory of plasticity derived the following equations and found normal rake angle, drill friction amgle.

Where,

and

From John-Cook material flow, Ernst and Merchant equation, shear flow angle calculated as ; f =feed, mm/rev, y1 = Initiation height of the burr

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Shaw and Oxford [11, 12] in their work derived the .relation for cutting force of the drill bit (F z) in terms of shear strength of the material and burr initiation height in excellent manner, which is considered by the researchers in the field of burr formation in drilling to derive mathematical modeling. In Sofronas and Williams [2,13] work cutting force and drill thrust and burr initiation height relations given for uniform burr without drill cap, which is considered in the present modeling and found good results to estimate the burr height.

Fig. 1 Schematic burr formation model

; Where ; ; Finally burr height, Burr height is obtained from math lab@2010 software, by generating the code for above model, then by substituting the feeding input values. 2.2 Simulation using Deform TM – 3D Deform, short for Design Environment for Forming, is a product of Scientific Forming Technologies Company (SFTC) and is a commercially available FEM solver that can be applied to several manufacturing processes. The results obtained from FEM solver is compared for exp.10 because it is not possible to show all the images, but values are tabulated in for comparison finally. 3. Experiments by Taguchi Methodology The orthogonal array forms the basis for the experimental analysis in the Taguchi method [14,15]. The selection of orthogonal array is concerned with the total degree of freedom of process parameters. There by, a L27 orthogonal array having degree of freedom equal to (27-1) 26 has been considered, which is used to optimize the drilling parameters for thrust force. Thereby burr height is found for optimum solution of drill thrust by taguchi technique. A mathematical model for thrust force and burr formation in drilling operation is developed. Thereby validating these models, experiments are conducted by varying different process parameters, which are depicted in table.1. The

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values obtained from experimentation are compared with simulated results developed in Deform TM -3D (Shown in fig.2).

Fig.2 Images generated from Simulation by DeformTM -3D results for experiment.10 Table.1 Levels and Factors as per Taguchi Method LEVELS

1

FACTORS CUTTING SPEED (rpm) A

FEED RATE (mm/min) B

DRILL DIAMETER (mm) C

POINT ANGLE ( 0 ) D

CLEARANCE ANGLE(o) E

465

18

8

1000

40

0

60 80

2

695

20

10

110

3

795

26

12

1180

Fig.3 Flow chart for present study

Fig.4 Radial drilling machine

Reddy Sreenivasulu et al. Manufacturing00 / Procedia Manufacturing 20 (2018) 458–463 Author name / Procedia (2017) 000–000

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3.1 Schematic Machining In the present work, the experiments were carried out on a Radial drilling machine (Make: Siddapura Machine Tools, Gujarat, INDIA) to perform different size of holes on Al 6061 alloy ( 300x50x10mm size) by alter the point and clearance angles on standard HSS twist drill bits and maintain constant helix angle of 30 degrees (Fig.3&4). Furthermore the speed (rpm), feed rate (mm/rev) and drill diameter (mm) are varied. Thrust force is measured by kistler dynamometer type 9272 (Kistler Instrumente AG, CH8408, Winterthur, Switzerland), Multichannel signal amplifier (kistler type 5070) while drilling.

4. Results Discussions Table.2 Results of thrust force from modeling, simulation and experiment Trial No.

1

2

3

4

5

6

7

8

9

10

11

12

13

EXP.

238

249

297

259

223

241

328

297

315

281

231

146

208

Deform-3D

247

224

203

294

227

205

238

335

333

219

234

184

201

Analytical

244

207

286

268

234

262

296

314

306

248

207

169

184

Trial No.

14

15

16

17

18

19

20

21

22

23

24

25

26

27

EXP.

193

163

204

238

226

225

257

224

192

202

138

147

116

233

Deform-3D

161

193

206

237

255

267

287

258

164

197

143

154

134

247

Analytical

174

172

197

236

217

223

243

246

175

219

117

119

109

264

Fig.5 Comparison of the thrust forces obtained from the experimental and numerical studies

The variations of the thrust force obtained at the end of the experimental, analytical and simulation studies are given in table.2 and in fig.5, it is found that there is a good agreement between the experimental and numerical results. The maximum deviation between the experimental and numerical results is obtained in experiment.3 and 7

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from the drilling processes under drilling conditions rotational speed = 465 rpm, feed rate = 18mm/min, point angle =1000, drill diameter = 8mm and clearance angle = 80 and under drilling conditions rotational speed = 465 rpm, feed rate = 26mm/min, point angle =1180, drill diameter = 12mm and clearance angle = 4 0 with the 2-flute HSS drill twist drill. Despite of these deviations, there is up to 80% agreement between the thrust force values in the drilling processes under these drilling conditions. Finally, burr height (B h) evaluated from analytical model equations with thrust forces in above studies and also measured the same with optical microscope after completion of every experiment and compared these readings. 5. Conclusions The following are the conclusions drawn after comparing the experimental values with developed analytical as well as simulated results . The results shows good agreement with developed model. 

From lower spindle speed the thrust forces not agreed (70%) with Deform-3D, because lower the speed and feed more resistance from material surface to indentation /penetration of drill in to work piece. But, it is observed that analytical results are good agreement with experimental values in both the experiment.3 &7.



The reason is complexity in the design of drill bit in CATIA model, changing of clearance angle in the model not so easy in 3 dimensional planes. But, it is easy to change the clearance angles on drill bit conventionally on tool &cutter grinder. So that experimental values and analytical model values are agreed together with 95%.

References [1]. Gillespie, L.K., ―Burrs Produced by Drilling‖, Bendix Corporation, Unclassified Topical Report BDX-6131248, December 1975. [2]. Sofranos S.A.1975, the formation and controlling of drilling burrs, PhD Thesis, University of Detroit. [3].P. J. Arrazola, T. Özel, D. Umbrello, M. Davies and I. S. Jawahir, Recent advances in modelling of metal machining processes, CIRP Annals-Manufacturing Technology, 62 (2) (2013) 695-718. [4]. ISO 13715:2000 Geometrical Product Specifications (GPS), International Organization for Standardization, Geneve, Switzerland. [5]. T. Thepsonthi and T. Özel, 3-D finite element process simulation of micro-end milling Ti-6Al-4V titanium alloy: Experimental validations on chip flow and tool wear, Journal of Materials Processing Technology, 221 (2015) 128-145. [6]. Klocke, F., Raedt, H., Hoppe, S. (2001), ―2D FEM Simulation of the Orthogonal High Speed Cutting Process―, ASME Transactions, Machining Science and Technology, Vol. 5, No. 3, pp. 323-340. [7]. Deform 3D-V6.1 User‘s Manual. [8]. Aurich, J. C., at al. Burrs Analysis, Control and Removal, CIRP Annals manufacturing Technology, Vol. 58, pp.519-542. (2009). [9]. L.K.Lauderbaugh, Analysis of the effects of process parameters on exit burrs in drilling using a combined simulation and experimental approach. Journal of Material Processing Technology, Volume 209, 1909-1919, 2009 [10]. J S Strenkowski, C Hsieh, A J Shih An analytical finite element technique for predicting thrust force and torque in drilling. International journal of machine tools & manufacture, volume 44,413-1421, 2004 [11]. M.C. Shaw, Metal Cutting Principles, third ed., M.I.T., Cambridge, Mass., 1954 [12]. M.C. Shaw, C.J. Oxford, on the drilling of metals II—the torque and thrust of drilling, Transactions of ASME Volume 79, 139–148, 1957 [13] R.A. Williams, A study of the basic mechanics of the chisel edge of a twist drill, International Journal of Production Research 8 (1970) 325–343 [14] Reddy Sreenivasulu, Chalamalasetti SrinivasaRao, Effect of drilling parameters on Thrust force and Torque during Drilling of Aluminium 6061 Alloy, Journal of Mechanical Engineering, Vol. ME 46, December 2016 Transaction of the Mechanical Engineering Division, The Institution of Engineers, Bangladesh. [15] D.C. Montgomery ―Design and analysis of experiments‖, John Wiley and Sons, New York, 2001.