San Jose State University Department of Mechanical Engineering

1
San Jose State University Department of
Mechanical Engineering

• Large Optics Diamond Turning Machine
• Presented by
• Vu Dao
• Gilbert Wong

2
Agenda

• Introduction
• Advantages
• Precision
• Design
• Summary
• QA

3
Introduction

• LODTM
• Large Optics Diamond Turning Machine
• High precision two axis vertical lathe
• Diamond cutting tool
• 64 in diameter, 20 in height, 3000lb
• Most precise vertical axis lathe currently
  available.

4
(No Transcript)
5
Advantages of LODTM

• Produce complex geometries
• Achieve high accuracy and repeatability
• Produce mirror finish surface

6
Precision

• Radial
• 28 nm (280Å)
• Surface finish
• 4.3 nm (42Å)
• Analogy
• 280Å is 3500 times smaller than
• diameter of human hair

7
Metrology System

• Metrology frame
• Kinematically mounted to LODTM frame by three
  blade flexures
• Super Invar
• Very low CTE, 0.6310-6/C
• Liquid Cooling
• Double-walled panels surrounding the metrology
  frame
• Uniform temperature of 0.001F

8
Motion Control

• Interferometer
• Resolution .618nm
• Closed loop
• Relative measurement

Baird, 1999
9
Motion Control
Baird, 1999
10
Motion Control

• Bearings
• Fluid-film for smooth friction free motion
• Radial, Thrust
• Water cooled to prevent heat generation
• Analog Servos
• One for X and Z axis
• 25.4 mm/sec machining speed
• Fast Tool Servo

11
Cutting Motion
Donaldson, 1983
12
Environmental Control

• Four pneumatic isolators
• Acoustic vibration isolation
• Air Flow (External)
• Uniform temperature of 0.01F

Patterson, 1987
13
Summary

• Highest accuracy turning machine
• Strict temperature control
• Primarily used to produce precision lens

14
References

• Baird, E.D., Patterson, S.R, Donaldson, R.R.,
  The Laser Interferometer System for the Large
  Optics Diamond Turning Machine, UCRL-ID-134693,
  Lawrence Livermore National Laboratory, 1999.
• Donaldson, R.R., Patterson, S., Design and
  Construction of A Large Vertical Axis Diamond
  Turning Machine, UCRL-89738, Lawrence Livermore
  National Laboratory, 1983.
• McCue, H., The Motion Control System for the
  Large Optics Diamond Turning Machine,
  UCRL-86438, Lawrence Livermore National
  Laboratory, 1981.
• Patterson, S., Inspection of the Large Optics
  Diamond Turning Machine, UCRL-97696, Lawrence
  Livermore National Laboratory, 1987.
• Hamilton, Jim., Large Optics Diamond Turning
  Machine, UCRL-TB-147593, Lawrence Livermore
  National Laboratory, 2002.