Research Papers

A Porous-Restricted Aerostatic Lead Screw Actuator for High Performance Microscale Machine Tools

[+] Author and Article Information
James Zhu

Graduate Research Assistant

Shiv G. Kapoor

Grayce Wicall Gauthier Chair in Mechanical Science and Engineering
e-mail: sgkapoor@illinois.edu

Richard E. DeVor

College of Engineering Distinguished Professor of Manufacturing
Department of Mechanical Science and Engineering,
University of Illinois,
Urbana-Champaign, Urbana, IL 61801

Jong-Kweon Park

Department of Ultra Precision
Machines and Systems,
Korea Institute of Machinery & Materials,
Daejeon 305-343, Korea

Contributed by the Manufacturing Engineering Division of ASME for publication in the JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING. Manuscript received February 27, 2012; final manuscript received July 3, 2012; published online January 7, 2013. Assoc. Editor: Tony Schmitz.

J. Manuf. Sci. Eng 135(1), 011002 (Jan 07, 2013) (8 pages) Paper No: MANU-12-1065; doi: 10.1115/1.4023111 History: Received February 27, 2012; Revised July 03, 2012

The design and manufacturing process for a porous-restricted aerostatic lead screw actuator (ALSA) is presented. The ALSA provides near-frictionless motion with submicron positioning accuracy, high stiffness at low inlet air pressures (<827 kPa), and a travel length of 50 mm. Porous graphite disk inserts are held in a helical pattern in an aerostatic nut housing against a lead screw thread to create multiple simultaneous air bearing surfaces. A wave spring flexure is inserted behind each graphite disk to provide a preload and ensure full contact between the porous graphite disk surface and the lead screw flank. When the wave spring flexures and graphite disks are potted in combination with a slow-curing epoxy, this creates a self-aligning method to consistently match all graphite disk insert surfaces to the helical profile of the lead screw thread. Experimental trials were performed to evaluate the performance of the manufactured ALSA. It was found that a stable nut with a per-thread stiffness of 9.7 N/μm was achievable with a 3.5 μm air gap and an overall permeability of 5.4 × 10−15 m2. Applications requiring higher stiffness may couple two or more single-threaded nuts to achieve the desired actuator stiffness.

Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
Fig. 1

Porous-restricted air bearing concept

Grahic Jump Location
Fig. 2

Aerostatic nut housing

Grahic Jump Location
Fig. 3

Effect of inlet pressure on (a) lift-off force and (b) stiffness for a single porous graphite disk at a constant permeability of 6.6 × 10−15 m2

Grahic Jump Location
Fig. 4

Effect of permeability on (a) lift-off force and (b) stiffness for a single porous graphite disk at a constant pressure of 827 kPa

Grahic Jump Location
Fig. 5

Stiffness for a pair of air bearing disks with increasing thread count

Grahic Jump Location
Fig. 6

Wave spring flexure configuration

Grahic Jump Location
Fig. 7

Velocity vectors shaded by static pressure (Pascal)

Grahic Jump Location
Fig. 8

Nut housing and enclosure

Grahic Jump Location
Fig. 9

Modified trapezoidal thread profile (mm)

Grahic Jump Location
Fig. 10

ALSA with precision lapping system

Grahic Jump Location
Fig. 11

Key elements of the precision lapping system

Grahic Jump Location
Fig. 12

ALSA platform for manufacturing and testing purposes

Grahic Jump Location
Fig. 13

Graphite disk after rough lap

Grahic Jump Location
Fig. 14

Aerostatic nut during permanent potting

Grahic Jump Location
Fig. 15

Surface restriction layer process

Grahic Jump Location
Fig. 16

Air gap calculation

Grahic Jump Location
Fig. 17

Stiffness measurement on ALSA




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