Browse Prior Art Database

Rotary fast tool servo component design

IP.com Disclosure Number: IPCOM000128096D
Original Publication Date: 1999-Dec-31
Included in the Prior Art Database: 2005-Sep-14
Document File: 6 page(s) / 23K

Publishing Venue

Software Patent Institute

Related People

Chargin, David Anthony: AUTHOR [+3]

Related Documents

http://theses.mit.edu:80/Dienst/UI/2.0/Describe/0018.mit.theses/1999-27: URL

Abstract

This thesis covers the design and implementation of the components of a novel rotary fast tool servo (RIFTS). The RFTS enables diamond turning of rotationally asymmetric optics, with an emphasis on eyeglass lenses. These components include the rotary arm which supports the cutting tool, a high resolution angular sensor for position feedback, and a labyrinth seal system to protect the rotary axis hearings.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 23% of the total text.

Page 1 of 6

 This record is the front matter from a document that appears on a server at MIT and is used through permission from MIT. See http://theses.mit.edu:80/Dienst/UI/2.0/Describe/0018.mit.theses/1999-27 for copyright details and for the full document in image form.

Rotary fast tool servo component design

by

David Anthony Chargin

Abstract

This thesis covers the design and implementation of the components of a novel rotary fast tool servo (RIFTS). The RFTS enables diamond turning of rotationally asymmetric optics, with an emphasis on eyeglass lenses. These components include the rotary arm which supports the cutting tool, a high resolution angular sensor for position feedback, and a labyrinth seal system to protect the rotary axis hearings.

The design of the toolarm meets several conflicting challenges, including maintaining low rotational inertia and high stiffness while providing an integrated tool height adjustment mechanism. A new, novel " double-diaphragm " actuator is developed, which provides sub- micrometer level tool height adjustment. This actuator enables the toolarm to be constructed with little additional material, meeting the low inertia goals without, compromising stiffness.

The high resolution angular feedback sensor selected for the machine is a diffractive laser design. It was successfully interfaced into the machine, both mechanically and electrically, to provide 10 nanometer resolution in cutting tool location. This was essential in enabling the RFTS to turn lenses with micrometer accuracy.

Finally, a new possibility of developing rotational damping with a labyrinth bearing seal is explored. Rotational damping is created by exploiting the shear forces developed between a viscous fluid and a labyrinth with a fine gap size. This provides excellent sealing as well as rotational damping.

Thesis Supervisor: David L. Trumper Title: Associate Professor of Mechanical Engineering

[3]

[4]

Acknowledgments

Many people have been instrumental in helping me finish this work, and I cannot, give them enough thanks. My thesis advisor, Professor David Trumper, has given isle the guidance I needed on this project. His seemingly endless knowledge of precision engineering and creative ideas put me on the right track and enriched my MIT experience beyond measure. I am proud to have worked with him. Professor Alex Siocuin also contributed his advice on the toolarm, and his enthusiasm for engineering was inspirational.

Massachusetts Institute of Technology Page 1 Dec 31, 1999

Page 2 of 6

Rotary fast tool servo component design

I have had the good fortune to work with several great students on this project. This diamond turning machine is really Stephen Ludwick's baby, not just his doctoral thesis work, and he deserves all the accolades for it. I never realized how great Pittsburgh was until I worked with Steve. David Ma and Joseph Calzaretta were always ready to lend not just their professional support, but also their friendship. Several compa...