General Competition (July 1995)

Non-Contact Optical Metrology of Complex Surface Forms for Precision Industrial Manufacturing

Sponsor: Corning Tropel Corporation (formerly Tropel Corporation)

• Project Performance Period: 8/1/1995 - 3/31/1998
• Total project (est.): $2,038,789.00
• Requested ATP funds: $924,179.00

Precision measurement systems are not only the heart but often the bottleneck of precision manufacturing. When parts must be made to exacting tolerances--high-performance engine components are an example--the manufacturer has only a few real options. Laser interferometry can be done rapidly and with extraordinary accuracy, but has always been limited to very simple surfaces: flats and spheres. More complex shapes must be measured by physical contact, generally using a coordinate measuring machine (CMM). The CMM moves a tiny contact probe around the surface, touching here and there to build up a set of measurement points that can be used to assure that the object is within tolerances. This process is slow and painstaking, and can't be used for real-time process control. TROPEL proposes to develop a unique optical measurement technology to apply the multiplexing and non-contact advantages of laser interferometry to more complex shapes: interior and exterior surfaces of industrially relevant cylinders and cones to begin with. Common optical components cannot generate the complex optical wavefronts needed to apply laser interferometry to surfaces more complex than a simple plane or sphere. TROPEL plans to use diffractive optics, produced using the lithography techniques used in the semiconductor industry for processing silicon wafers, to produce the required complex wavefronts to realize this technology. If successful the project will enable the development of laser interferometry measuring systems for complex shapes that are 10 to 100 times faster and 5 to 10 times more accurate than the mechanical measurement systems they replace. In addition to putting the United States at the forefront of the precision metrology industry, the new technology would be of significant importance to U.S. manufacturers of precision parts, potentially enabling extremely accurate, in-line measurement of parts as they are being machined.

For project information:

Louis Denes, (716) 388-3469
ld@tropel.com

ATP Project Manager

Thomas Lettieri, (301) 975-3496
thomas.lettieri@nist.gov