0
Research Papers

On Crack Control Strategy in Near-Field Microwave Drilling of Soda Lime Glass Using Precursors

[+] Author and Article Information
Nitin Kumar Lautre

Department of Mechanical
and Industrial Engineering,
Indian Institute of Technology Roorkee,
Roorkee, Uttarakhand 247 667, India
e-mail: nfl_123@rediffmail.com

Apurbba Kumar Sharma

Department of Mechanical
and Industrial Engineering,
Indian Institute of Technology Roorkee,
Roorkee, Uttarakhand 247 667, India
e-mail: akshafme@gmail.com

Shantanu Das

Reactor Control Division,
Bhabha Atomic Research Center,
Mumbai 400 085, India
e-mail: shantanu@barc.gov.in

Pradeep Kumar

Office of the Vice Chancellor,
Delhi Technical University,
Bawana Road,
Rohini, Delhi 110 042, India
e-mail: kumarfme@gmail.com

1Corresponding author.

Contributed by the Heat Transfer Division of ASME for publication in the JOURNAL OF THERMAL SCIENCE AND ENGINEERING APPLICATIONS. Manuscript received January 9, 2015; final manuscript received April 19, 2015; published online June 2, 2015. Assoc. Editor: Bengt Sunden.

J. Thermal Sci. Eng. Appl 7(4), 041001 (Dec 01, 2015) (15 pages) Paper No: TSEA-15-1017; doi: 10.1115/1.4030478 History: Received January 09, 2015; Revised April 19, 2015; Online June 02, 2015

Processing of glass is indeed challenging owing to its chemical passivity; it is prone to cracking while processing through mechanical and thermal modes without appropriate strategies. Near-field microwave drilling is a thermal-ablation based material removal technique of generating high heat flux in the targeted area. Glasses tend to fail quite frequently during this processing owing to thermal stresses (shock). It was therefore important to develop suitable strategies to minimize cracking during this potentially pragmatic process for microdrilling. Accordingly, in the present work, an attempt was made to change the medium of the interface at the target drilling zone through application of seven different surface precursors to influence the local heat-flow characteristics. The cracking behavior of the soda lime glass during microwave drilling in a customized applicator under controlled power input (90–900 W) at 2.45 GHz was investigated. The heat was generated inside the applicator by creating a plasma sphere in the drilling zone through a metallic concentrator. The thermal shock on the glass specimen was found reduced by the combination of a good dielectric precursor and microwave concentration for hotspot formation, which in turn, reduces the cracking/crazing tendency. Trials were carried out while drilling holes on 1.2 mm thick glass plates at various duty cycles (DCs) to study the crack intensity and pattern. The near-field microwave drilling condition was also simulated to obtain the contours of the induced stresses. The results so obtained were compared with the cracking signatures of the experimental outputs; a good correlation could be obtained. It was found that both solid and liquid fluxes as precursor could be effective to control cracking during microwave drilling.

Copyright © 2015 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

A schematic of the customized setup used for microwave drilling; insets: (a) epoxy precursor and (b) engine oil precursor on x–y plane

Grahic Jump Location
Fig. 2

Plasma formation and heat generation at the drill tool tip during microwave drilling

Grahic Jump Location
Fig. 3

Meshing pattern of the tool–workpiece interaction zone: (a) without precursor and (b) with precursor

Grahic Jump Location
Fig. 4

Major heat transfer modes in microwave drilling

Grahic Jump Location
Fig. 5

An image of a microwave drilled hole and the cracks developed

Grahic Jump Location
Fig. 6

Typical simulated result of the critically stressed area in the plasma zone on the surface of glass workpiece

Grahic Jump Location
Fig. 7

Copper tool tip: (a) before, (b) after (DC = 0.20) microwave drilling with liquid precursors at low power (90 W), and (c) copper tool tip melted at DC = 1 (900 W) during microwave drilling with precursor

Grahic Jump Location
Fig. 8

Copper tool covered and trapped in microwave drilled cavity (nailing)

Grahic Jump Location
Fig. 9

Microwave cutting of hole through nailing: (a) without precursor and (b) with oil precursor

Grahic Jump Location
Fig. 10

(a) Random crack developed in glass specimen without precursor and (b) critically stressed zone as observed through simulation

Grahic Jump Location
Fig. 11

Simulation of heat distribution on glass surface during microwave drilling; inset: stress distribution in HAZ

Grahic Jump Location
Fig. 12

von Mises stress distribution on glass specimen due to the influence of the microwave plasma in: (a) top view without tool and (b) side view with tool

Grahic Jump Location
Fig. 13

Plasma ball temperature distribution

Grahic Jump Location
Fig. 14

Convergence of simulation iterations

Grahic Jump Location
Fig. 19

A hole with bromide based flux (DC = 1, 20 s)

Grahic Jump Location
Fig. 20

(a) Holes drilled with glycerin at DC = 0.20, 35 s; (b) burnt specimen at DC = 1, 40 s; (c) hole failure around the nailed region at DC = 0.20, 45 s; and (d) random cracking under nonuniform precursor distribution at DC = 0.20, 20 s

Grahic Jump Location
Fig. 21

(a) A typical hole drilled with blue perspex precursor at DC = 1, 20 s; (b) exit side image of the eroded perspex burn at DC = 1, 40 s; and (c) an SEM image of the thermally eroded zone of the perspex

Grahic Jump Location
Fig. 22

Distribution of von Mises stresses on precursor and glass specimen: (a) top view and (b) side view

Grahic Jump Location
Fig. 23

Typical temperature distribution in the interaction zone over the glass specimen

Grahic Jump Location
Fig. 18

Holes with etched surface with resin at: (a) DC = 0.20, 180 s and (b) DC = 0.25, 180 s

Grahic Jump Location
Fig. 17

Microwave hole with olive oil precursor: (a) burnt blind hole and (b) crack formation

Grahic Jump Location
Fig. 16

Microwave hole drilled with engine oil precursor at: (a) DC = 0.75, (b) DC = 1, and (c) crack developed with engine oil precursor at 600–900 W, 30 s

Grahic Jump Location
Fig. 15

Spreading of wax over glass during drilling at: (a) DC = 0.20, (b) DC = 0.50, and (c) cross crack at DC = 0.75 (600 W) with wax precursor

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In