0
Research Papers

Comparative Assessment of the Laser Induced Plasma Micromachining and the Micro-EDM Processes

[+] Author and Article Information
K. Pallav

e-mail: kumarpallav2008@u.northwestern.edu

P. Han

Department of Mechanical Engineering,
Northwestern University,
Evanston, IL 60201

J. Ramkumar

Department of Mechanical Engineering,
Indian Institute of Technology,
Kanpur, India

Nagahanumaiah

Central Mechanical Engineering
Research Institute,
Durgapur, India

K. F. Ehmann

Department of Mechanical Engineering,
Northwestern University,
Evanston, IL

1Corresponding author.

Manuscript received August 15, 2011; final manuscript received August 16, 2013; published online November 5, 2013. Editor: Y. Lawrence Yao.

J. Manuf. Sci. Eng 136(1), 011001 (Nov 05, 2013) (16 pages) Paper No: MANU-11-1275; doi: 10.1115/1.4025391 History: Received August 15, 2011; Revised August 16, 2013

Micro-electro-discharge machining (micro-EDM) is a well-established micromanufacturing process and has been at the center of research for the last few decades. However, it has its own limitations. The limitations are primarily due to the requirement of a tool and electric potential between the tool and the workpiece. The laser induced plasma micromachining (LIP-MM) is a novel tool-less multimaterial selective material removal type of micromachining process. In a manner similar to micro-EDM, it also removes material through plasma-matter interaction. However, instead of a tool and electric potential, it uses an ultra-short laser beam to generate plasma within a transparent dielectric media and thus circumvents some of the limitations associated with micro-EDM. The paper presents an experimental investigation on the comparative assessment of the capabilities of the two processes in the machining of microchannels in stainless steel. For comparative assessment of their processing capabilities, microchannels were machined by the two processes at similar pulse energy levels, while other process parameters were maintained at their optimal values for their respective process technology requirements. The comparative assessment was based on the geometric characteristics, material removal rate (MRR), effect of tool wear, and the range of machinable materials.

Copyright © 2014 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Dependence of the plasma occurrence probability on the peak power density

Grahic Jump Location
Fig. 2

Images of plasma obtained through a CCD camera at: (a) super-threshold peak power density value of 2 × 1011W/cm2 at 20 kHz, (b) near the threshold peak power density value of 1.2 × 1011W/cm2 at 20 kHz pulse repetition rate

Grahic Jump Location
Fig. 3

Process schematics of the micro-ED milling process

Grahic Jump Location
Fig. 4

Process schematics for the LIP-MM process

Grahic Jump Location
Fig. 10

Longitudinal depth profile of a typical microchannel machined by LIP-MM at pulse energy level of 4 μJ and feed-rate was 2000 μm/s, measured at the (a) center, (b) left edge, and (c) right edge

Grahic Jump Location
Fig. 8

Longitudinal depth profile of a typical microchannel made by micro-EDM at feed-rate of 30 μm/sec, pulse energy of 6 μJ, and spark gap of 5 μm, measured at the (a) center, (b) left edge, and (c) right edge

Grahic Jump Location
Fig. 9

Longitudinal depth profile of a typical microchannel made by micro-EDM at feed-rate of 10 μm/sec, pulse energy of 6 μJ, and spark gap of 5 μm, measured at the (a) center, (b) left edge, and (c) right edge

Grahic Jump Location
Fig. 5

Images of a typical microchannel made by micro-EDM (a) 3D profile, (b) transverse depth profile

Grahic Jump Location
Fig. 6

Images of a typical microchannel made by LIP-MM (a) 3D model, (b) transverse depth profile

Grahic Jump Location
Fig. 7

Transverse depth profile of a typical microchannel (a) machined by micro-EDM at 6 μJ pulse energy, 5 μm spark gap and 10 μm/s feed-rate, (b) machined by LIP-MM at 6 μJ pulse energy and 800 μm/s feed-rate

Grahic Jump Location
Fig. 12

Microscopic images of the machined surface of a typical single pass microchannel machined at 4 μJ pulse energy and 2000 μm/s feed-rate; and multipass microchannel machined at 4 μJ pulse energy, 18 μm lateral overlapping and 400 μm/s feed-rate by LIP-MM

Grahic Jump Location
Fig. 11

Microscopic image and cross-sectional depth profile measured through a white light interferometer at two different locations of a microchannel machined by micro-EDM at feed-rate of 10 μm/s, pulse energy of 6 μJ, and spark gap of 5 μm

Grahic Jump Location
Fig. 13

Transverse depth profile for single-pass and multipass microchannels shown in Fig. 12

Grahic Jump Location
Fig. 14

Effect of tool wear on the geometric accuracy of microchannels (a) transverse depth profile showing formation of unmachined zone, (b) and (c) microscopic images of the microchannels that show high surface roughness due to multiple plasma discharges and formation of unmachined zones (encircled) with micro-EDM

Grahic Jump Location
Fig. 15

Effect of tool wear on the width profile along the length of microchannels machined by micro-EDM

Grahic Jump Location
Fig. 16

Microscopic images of typical craters machined by multiple plasma discharges (100, 50, 10, and 1) in stainless steel by the LIP-MM process

Grahic Jump Location
Fig. 17

3D profile and microscopic image showing the uniform width profile along the length of a microchannel machined by LIP-MM at pulse energy of 4 μJ and feed-rate of 400 μm/s.

Grahic Jump Location
Fig. 18

Dependence of the mean cross-sectional depth for single pass microchannels on the feed-rate (a) LIP-MM process, (b) Micro-EDM process

Grahic Jump Location
Fig. 20

Microscopic images of a multipass microchannel machined in borosilicate glass by the LIP-MM process at 18 μm overlap, (a) microwedge, (b) side walls, (c) corner, and (d) machined surface

Grahic Jump Location
Fig. 21

Microscopic images of the wall in-between two adjacent multipass microchannels machined in borosilicate glass by the LIP-MM

Grahic Jump Location
Fig. 19

Transverse depth profile of a typical microchannel machined in quartz by LIP-MM

Grahic Jump Location
Fig. 22

Microscopic images of typical multiple and single pass and microchannels machined in PCBN by the LIP-MM process

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