Research Papers

Effect of Process Parameters on Burrs Produced in Micromilling of a Thin Nitinol Foil

[+] Author and Article Information
George K. Mathai

e-mail: georgekm@gatech.edu

Shreyes N. Melkote

e-mail: shreyes.melkote@me.gatech.edu

David W. Rosen

e-mail: david.rosen@me.gatech.edu
The George W. Woodruff School
of Mechanical Engineering,
Georgia Institute of Technology,
Atlanta, GA 30332

Contributed by the Manufacturing Engineering Division of ASME for publication in the JOURNAL OF MICRO- AND NANO-MANUFACTURING. Manuscript received October 21, 2012; final manuscript received March 18, 2013; published online May 2, 2013. Assoc. Editor: Stefan Dimov.

J. Micro Nano-Manuf 1(2), 021005 (May 02, 2013) (10 pages) Paper No: JMNM-12-1070; doi: 10.1115/1.4024099 History: Received October 21, 2012; Revised March 18, 2013

This paper examines the formation of burrs in micromilling of a thin nickel–titanium alloy (nitinol) foil used in implantable biomedical device applications. The paper analyzes the effects of key micromilling process parameters such as spindle speed, feed, tool wear, backing material, and adhesive used to attach the foil to the backing material on the burr height. It is found that burr height is larger on the downmilling side for grooves cut with a worn tool at high feeds, low spindle speeds with a softer backing material, and a weaker adhesive bond. Some important interaction effects of these factors are also studied. The study also shows that the mechanics of burr formation in such thin materials depends on whether the mode of cutting is dominated by tearing or chip formation, which is a function of the feed rate. A kinematic model to predict burr widths is developed and verified through experiments.

Copyright © 2013 by ASME
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Microlution, “Case Studies,” Accessed Nov. 15, 2012, microlution-inc.com/solutions/casestudies.php
Kathuria, Y. P., 2005, “Laser Microprocessing of Metallic Stent for Medical Therapy,” J. Mater. Process. Tech., 170(3), pp. 545–550. [CrossRef]
Takahata, K., and Gianchandani, Y., 2004, “A Planar Approach for Manufacturing Cardiac Stents: Design, Fabrication, and Mechanical Evaluation,” J. Microelec. Syst., 13(6), pp. 933–939. [CrossRef]
Cassidy, V., 2008, “Ultrafast Track: The buzz about ultrafast-pulse lasers gets louder,” MICROmanufacturing, 1(2), www.micromanufacturing.com
Schaffer, C. B., Brodeur, A., and Mazur, E., 2001, “Laser-Induced Breakdown and Damage in Bulk Transparent Materials Induced by Tightly Focused Femtosecond Laser Pulses,” Meas. Sci. Tech., 12(11), pp. 1784–1794. [CrossRef]
Gillespie, L. K., Neal, B. J., and Albright, R. K., 1976, “Burrs Produced by End Milling,” Bendix Corp., Kansas, Technical Report No. BDX-613-1503.
Lee, K., and Dornfeld, D., 2005, “Micro-Burr Formation and Minimization through Process Control,” Precision Eng., 29(2), pp. 246–252. [CrossRef]
Chern, G., Wu, Y., Cheng, J., and Yao, J., 2007, “Study on Burr Formation in Micro-Machining Using Micro-Tools Fabricated by Micro-Edm,” Precision Eng., 31(2), pp. 122–129. [CrossRef]
Olvera, O., and Barrow, G., 1998, “Influence of Exit Angle and Tool Nose Geometry on Burr Formation in Face Milling Operations,” I. Mech. Eng. B J. Eng. Manf., 212(1), pp. 59–72. [CrossRef]
Dornfeld, D. A., and Min, S., 2009, “A Review of Burr Formation in Machining,” Proceedings of the CIRP International Conference on Burrs, Kaiserslautern, Germany, 1, pp. 3–11.
Stein, J. M., and Dornfeld, D. A., 1997, “Burr Formation in Drilling Miniature Holes,” CIRP Ann. Manf. Tech., 46(1), pp. 63–66. [CrossRef]
Lee, K., and Dornfeld, D., 2002, “An Experimental Study on Burr Formation in Micro Milling Aluminum and Copper,” Trans. NAMRI/SME, 30, pp. 255–262.
Liu, X., Devor, R. E., and Kapoor, S. G., 2004, “The Mechanics of Machining at the Microscale: Assessment of the Current State of the Science,” J. Manf. Sci. Eng., 126(4), pp. 666–678. [CrossRef]
Cambron, S., Keynton, R., and Franco, J., 2003, “Design and Fabrication of Microtacks for Retinal Implant Applications,” International Mechanical Engineering Congress and Exposition (IMECE2003), Washington, DC, pp. 247–249.
Melkote, S. N., Newton, T. R., Hellstern, C., Morehouse, J. B., and Turner, S., 2010, “Interfacial Burr Formation in Drilling of Stacked Aerospace Materials,” Proceedings of the CIRP International Conference on Burrs, Kaiserslautern, Germany, 1, pp. 89–98.
Guo, Y. B., and Dornfeld, D., 1998, “Finite Element Analysis of Drilling Burr Minimization with a Backup Material,” Trans. NAMRI/SME, 26, pp. 207–212.
Marusich, T. D., Usui, S., Ma, J., Stephenson, D. A., and Shih, A., 2007, “Finite Element Modeling of Drilling Process With Solid and Indexable Tooling in Metal and Stack-Ups,” 10th CIRP International Workshop on Modeling of Machining Operations, Reggio Calabria, Italy, pp. 51–57.
Zheng, L., Wang, C., Yang, L., Song, Y., and Fu, L., 2012, “Characteristics of Chip Formation in the Micro-Drilling of Multi-Material Sheets,” Int. J. Mach. Tool Man., 52(1), pp. 40–49. [CrossRef]
ASTM, 2010, “Standard Test Method for Peel or Stripping Strength on Adhesive Bonds,” D903-98, ASTM International, West Conshohocken, PA, pp. 1–3.
Filiz, S., Conley, C., Wasserman, M., and Ozdoganlar, O., 2007, “An Experimental Investigation of Micro-Machinability of Copper 101 Using Tungsten Carbide Micro-Endmills,” Int. J. Mach. Tool Man., 47(8), pp. 1088–1100. [CrossRef]
Aramcharoen, A., and Mativenga, P. T., 2009, “Size Effect and Tool Geometry in Micromilling of Tool Steel,” Precision Eng., 33(4), pp. 402–407. [CrossRef]
Pelton, A. R., Dicello, J., and Miyazaki, S., 2000, “Optimisation of Processing and Properties of Medical Grade Nitinol Wire,” Proceedings of the International Conference on Shape Memory and Superelastic Technologies, Pacific Grove, CA, pp. 361–374.
Buehler, W. J., and Wang, F. E., 1968, “A Summary of Recent Research on the Nitinol Alloys and Their Potential Application in Ocean Engineering,” Ocean Eng., 1(1), pp. 105–120. [CrossRef]


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Fig. 2

Experimental setup

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Fig. 3

Tool wear: (a) new tool, (b) used tool, (c) used tool (portion that contacts foil), (d) worn tool, and (e) detail view of worn tool

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Fig. 4

Measurement of peel strength: (a) test setup, (b) comparison of peel strength, pc = PMMA backing material with cyanoacrylate adhesive, pe = PMMA backing material with epoxy adhesive, ac = aluminum backing material with cyanoacrylate adhesive, ae = aluminum backing material with epoxy adhesive

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Fig. 5

High speed video stills of burr formation: (a) stage 1: foil pushed up, (b) stage 2: foil tearing, (c) stage 3: foil tearing closer to upmilling side, (d) burr fracture (before), (e) burr fracture (after), (f) foil machining by chip formation, and (g) burr formation with slow feed viewed from upmilling side

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Fig. 6

Chip formation: (a) PMMA chip, foil interaction, (b) large, continuous PMMA chip, (c) large continuous aluminum chip, and (d) epoxy chip and machined foil

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Fig. 7

Burr shapes: (a) rollover type, (b) feathery type, (c) wall type, (d) small, evenly spaced rollover type, 10 μm/tooth, and (e) small, evenly spaced rollover type, 1 μm/tooth

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Fig. 8

Schematic of burr formation: (a) rollover type, (b) wall type, (c) wall type with low feed

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Fig. 9

Histogram of burr height for grooves milled with PMMA backing, cyanoacrylate adhesive and a new tool (N = spindle speed: − = 30,000 rpm, + = 60,000 rpm, fz = feed: − = 1 μm/tooth, + = 10 μm/tooth, m = milling side: − = downmilling, + = upmilling)

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Fig. 10

Boxplot of burr height for grooves milled with PMMA backing, cyanoacrylate adhesive and a new tool

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Fig. 11

Mean effects plot (A = adhesive: − = cyanoacrylate, + = epoxy, M: backing material: − = PMMA, + = aluminum, W = tool wear: − = new tool, + = worn tool, N = spindle speed: − = 30,000 rpm, + = 60,000 rpm, fz = feed: − = 1 μm/tooth, + = 10 μm/tooth, m = milling side: − = downmilling, + = upmilling)

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Fig. 12

Interaction effects plot (A = adhesive: − = cyanoacrylate, + = epoxy, M: backing material: − = PMMA, += aluminum, W= tool wear: − = new tool, + = worn tool, N = spindle speed: − = 30,000 rpm, + = 60,000 rpm, fz = feed: − = 1 μm/tooth, + = 10 μm/tooth, m= milling side: − =downmilling, + = upmilling)

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Fig. 13

Effect of feed on burr height: (a) upmilling side, (b) downmilling side, (c) 1 μm/tooth, (d) 2.5 μm/tooth, (e) 5 μm/tooth, (f) 7.5 μm/tooth, (g) 10 μm/tooth, (h) 25 μm/tooth, (i) 50 μm/tooth, and (j) 100 μm/tooth. Images oriented with upmilling side towards the top.

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Fig. 14

Burr formation model: (a) schematic of tooth engaging with foil, (b) enlarged view of tooth before penetration into foil, (c) kinematics of foil at tooth tip, (d) force balance in foil, (e) undeformed length and strained length at failure when εt  < εf, and (f) foil failure at initial penetration when εt  > εf

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Fig. 15

Predicted versus experimental burr width




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