1. San Jose State University Department of Mechanical Engineering
Large Optics Diamond Turning Machine
Presented by
Vu Dao
Gilbert Wong
March 20, 2003
ME 250 Precision Machine Design

2. ME 250 Precision Machine Design
Agenda
Introduction
Advantages
Precision
Design
Summary
Q&A
March 20, 2003
ME 250 Precision Machine Design

3. ME 250 Precision Machine Design
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.
March 20, 2003
ME 250 Precision Machine Design

4. ME 250 Precision Machine Design
March 20, 2003
ME 250 Precision Machine Design

5. ME 250 Precision Machine Design
Advantages of LODTM
Produce complex geometries
Achieve high accuracy and repeatability
Produce mirror finish surface
March 20, 2003
ME 250 Precision Machine Design

6. ME 250 Precision Machine Design
Radial
28 nm (280Å)
Surface finish
4.3 nm (42Å)
Analogy
280Å is ~ 3500 times smaller than
diameter of human hair
March 20, 2003
ME 250 Precision Machine Design

7. ME 250 Precision Machine Design
Metrology System
Metrology frame
Kinematically mounted to LODTM frame by three blade flexures
Super Invar
Very low CTE, 0.63*10-6/°C
Liquid Cooling
Double-walled panels surrounding the metrology frame
Uniform temperature of 0.001°F
March 20, 2003
ME 250 Precision Machine Design

8. ME 250 Precision Machine Design
Motion Control
Interferometer
Resolution .618nm
Closed loop
Relative measurement
Baird, 1999
March 20, 2003
ME 250 Precision Machine Design

9. ME 250 Precision Machine Design
Motion Control
Baird, 1999
March 20, 2003
ME 250 Precision Machine Design

10. ME 250 Precision Machine Design
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
March 20, 2003
ME 250 Precision Machine Design

11. ME 250 Precision Machine Design
Cutting Motion
Donaldson, 1983
March 20, 2003
ME 250 Precision Machine Design

12. Environmental Control
Four pneumatic isolators
Acoustic vibration isolation
Air Flow (External)
Uniform temperature of 0.01°F
Patterson, 1987
March 20, 2003
ME 250 Precision Machine Design

13. ME 250 Precision Machine Design
Summary
Highest accuracy turning machine
Strict temperature control
Primarily used to produce precision lens
March 20, 2003
ME 250 Precision Machine Design

14. ME 250 Precision Machine Design
References
Baird, E.D., Patterson, S.R, Donaldson, R.R., “The Laser Interferometer System for the Large Optics Diamond Turning Machine,” UCRL-ID , 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 , Lawrence Livermore National Laboratory, 2002.
March 20, 2003
ME 250 Precision Machine Design