Education

Research Description

Dr. Dow's long-term goal is to improve how we make and measure devices that require tolerances of 1 part in 105 of the feature size to operate correctly. This means for a telescope measuring 1.5 meters (like the Hubbel Telescope), the shape tolerance is 15 micrometers.

Publications

Optics of balloon experimental twin telescope for infrared interferometry (BETTII): delay lines and alignment

Dhabal, A., Rinehart, S. A., Rizzo, M. J., Mundy, L., Fixsen, D., Sampler, H., Mentzell, E., Veach, T., Silverberg, R. F., Furst, S., Dow, T., Ade, P., & Tucker, C. (2016), In Optical and infrared interferometry and imaging v. (Proceedings of SPIE-the International Society for Optical Engineering, 9907).

Design and validation of the mounting structure for BETTII balloon-based telescope with thin-walled optics

Furst, S., Dow, T., Garrard, K., Sohn, A., Fixsen, D., Rinehart, S., Mentzell, E., Veach, T., Rizzo, M., & Dhabal, A. (2016), Journal of Astronomical Telescopes Instruments and Systems, 2(2).

Design of elliptically-vibrating ultrasonic actuator for nanocoining

Dow, T. A., Nowak, J., & Kessing, J. R. (2016), Precision Engineering, 45, 301-310.

Nanostructure fabrication on germanium and silicon by nanocoining imprint technique

Zdanowicz, E., Dow, T. A., Scattergood, R. O., & Youssef, K. (2013), Precision Engineering, 37(4), 871-879.

Thermo-chemical wear model and worn tool shapes for single-crystal diamond tools cutting steel

Lane, B. M., Dow, T. A., & Scattergood, R. (2013), Wear, 300(1-2), 216-224.

Rapid fabrication of nanostructured surfaces using nanocoining

Zdanowicz, E., Dow, T. A., & Scattergood, R. O. (2012), Nanotechnology, 23(41).

Design, modeling, fabrication, and evaluation of the air amplifier for improved detection of biomolecules by electrospray ionization mass spectrometry

Robichaud, G., Dixon, R. B., Potturi, A. S., Cassidy, D., Edwards, J. R., Sohn, A., Dow, T. A., & Muddiman, D. C. (2011), International Journal of Mass Spectrometry, 300(2-3), 99-107.

Diamond tool wear measurement by electron-beam-induced deposition

Shi, M., Lane, B., Mooney, C. B., Dow, T. A., & Scattergood, R. O. (2010), Precision Engineering, 34(4), 718-721.

Diamond tool wear when machining Al6061 and 1215 steel

Lane, B. M., Shi, M., Dow, T. A., & Scattergood, R. (2010), Wear, 268(11-12), 1434-1441.

Automated part centering with impulse actuation

Furst, S. J., Dow, T. A., Garrard, K., & Sohn, A. (2010), Journal of Manufacturing Science and Engineering, 132(1).

View all publications via NC State Libraries

Grants

Multi-Lens Array, PEC Enhancement Project

Oculus(3/01/17 - 12/31/18)

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Multi-Lens Array, PEC Enhancement Project

Sponsor: Oculus

Start Date: 3/01/17

End Date: 12/31/18

Abstract

The purpose of this work is study concepts needed to rapidly create molds for multi-lens arrays of small plastic optics. This project will build on previous work in the PEC sponsored by PEC Affiliates and NSF that led to a NCSU/PEC patent on Nano-coining of sub wave-length plastic features. Because the size of the features for this proposal are 100x larger than in the previous work, the concepts will need to be refined to achieve the larger size. In addition, the details of the shape of the individual lenses may need to be modified to create the desired geometry in the replicated lenses.

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Precision Metrology, PEC Core Project 2

PE CONSORTIUM(3/01/17 - 4/01/18)

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Precision Metrology, PEC Core Project 2

Sponsor: PE CONSORTIUM

Start Date: 3/01/17

End Date: 4/01/18

Abstract

The metrology of opto-mechanical systems has been an ongoing research task at the PEC for many years. This is required both to support the precision fabrication projects and to meet the needs of sponsors. For example, the production of freeform optical surfaces (NASA) and inertial confinement fusion targets (LANL) could not be performed without adequate tools for surface characterization. New technology is needed for metrology of contact lens molds and small transparent optics (J&J Vision Care) and for co-registration of multiple optical surfaces and their locating datums (Oculus) will require innovative solutions that are not commercially available. The activities in 2017 will involve improved methods for metrology of contact lenses using the Polaris 3D non-contacting profilometer and developing new SEM or AFM techniques to measure lens arrays created by the advanced NanoCoining process developed at the PEC.

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Precision Fabrication , PEC Core Project 1

PE CONSORTIUM(3/01/17 - 4/01/18)

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Precision Fabrication , PEC Core Project 1

Sponsor: PE CONSORTIUM

Start Date: 3/01/17

End Date: 4/01/18

Abstract

At the heart of Precision Engineering is the creation of surfaces that have features defined by the function of that surface. For example, a reflective mirror must have fine scale roughness that will not scatter the incident radiation of interest. The acceptable surface finish for visible wavelength optics is much smaller than for longer wavelength infrared mirrors. Therefore, the fabrication techniques of interest should be fast and accurate while controlling the shape and finish that provides the performance needed.

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Precision Actuation and Control, PEC Core Project 3

PE CONSORTIUM(3/01/17 - 4/01/18)

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Precision Actuation and Control, PEC Core Project 3

Sponsor: PE CONSORTIUM

Start Date: 3/01/17

End Date: 4/01/18

Abstract

The three foundations of precision engineering are fabrication, metrology and control. The first is the creation of a surface or mechanism, the second measuring its shape or motion and the third is finding a way to improve the result with feedback control. This third foundation has been applied to all of the systems utilized in the PEC and most, if not all, of the industrial systems in this area. The projects discussed above will all need a component of control to produce useful results. This task will involve all of the faculty, students and staff.

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Diamond Tool Wear and Surface Finish when Machining Plastic Optics, PEC Enhancement Project

Oculus(3/01/17 - 12/31/18)

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Diamond Tool Wear and Surface Finish when Machining Plastic Optics, PEC Enhancement Project

Sponsor: Oculus

Start Date: 3/01/17

End Date: 12/31/18

Abstract

The five plastic materials to be studied have a range of optical, material and mechanical properties that will influence the design, manufacturing process and longevity of the optical system. The proposed project will address the manufacturing part of the puzzle; specifically study the use of diamond tools in a precision lathe to produce an accurate shape with the optical finish needed for specular surfaces. The main objective is to find the relationship between the machining conditions (tool geometry/wear, surface speed, depth of cut) and the surface finish for the plastic materials to be studied. The work will address two different issues: 1) What are the best conditions to produce optical finishes (Ra < 5 nm) and 2) What is the magnitude and geometry of the wear and BuE (pickup) that occurs on the tool.

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Membership in PE Consortium, Full Member

Los Alamos National Laboratory(1/01/17 - 12/31/17)

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Membership in PE Consortium, Full Member

Sponsor: Los Alamos National Laboratory

Start Date: 1/01/17

End Date: 12/31/17

Abstract

This Agreement is made by and between North Carolina State University at Raleigh, North Carolina and Los Alamos National Laboratories. The parties to this Agreement intend to join together in a cooperative effort to support a University/Industry Precision Engineering Center at UNIVERSITY such that the UNIVERSITY environment can be used to develop a better understanding of Precision Engineering, stimulate industrial innovation; and provide UNIVERSITY with strengthened educational capability in these fields, and MEMBER with the latest advances in technology.

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Membership in PE Consortium, Full Member

Oculus(1/01/17 - 12/31/18)

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Membership in PE Consortium, Full Member

Sponsor: Oculus

Start Date: 1/01/17

End Date: 12/31/18

Abstract

This Agreement is made by and between North Carolina State University at Raleigh, North Carolina and Oculus. The parties to this Agreement intend to join together in a cooperative effort to support a University/Industry Precision Engineering Center at UNIVERSITY such that the UNIVERSITY environment can be used to develop a better understanding of Precision Engineering, stimulate industrial innovation; and provide UNIVERSITY with strengthened educational capability in these fields, and MEMBER with the latest advances in technology.

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Development of DAQ System for Grit Testing Machine

Saint-Gobain Abrasives, Inc.(11/01/16 - 8/31/17)

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Development of DAQ System for Grit Testing Machine

Sponsor: Saint-Gobain Abrasives, Inc.

Start Date: 11/01/16

End Date: 8/31/17

Abstract

The purpose of this work is to design and fabricate a data acquisition (DAQ) system for the grit testing platform being developed by Precitech for St. Gobain. The DAQ system must be capable of recording axis and force data during experiment and measurement modes, as well as generating trigger signals to coordinate the Precitech UPX controller, DAQ system, and the hi-speed camera. The collected data will be saved to a hard disk, and this proposal also includes development of basic post-process analysis tools to correlate the force data with surface height measurements, plot results, and calculate useful metrics like the ratio of force to groove area. The proposed tasks are: Task 1. Create DAQ System Design and Requirements Task 2. Sensor Signal Integration and Testing at the PEC Task 3. User Interface Design and Programming Task 4. Creation of Analysis Tools Task 5. Integrate System at St. Gobain Facility

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PEC Double Membership - Full Member

Los Alamos National Laboratory(1/01/16 - 12/31/16)

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PEC Double Membership - Full Member

Sponsor: Los Alamos National Laboratory

Start Date: 1/01/16

End Date: 12/31/16

Abstract

This Agreement is made by and between North Carolina State University at Raleigh, North Carolina and Los Alamos National Laboratories. The parties to this Agreement intend to join together in a cooperative effort to support a University/Industry Precision Engineering Center at UNIVERSITY such that the UNIVERSITY environment can be used to develop a better understanding of Precision Engineering, stimulate industrial innovation; and provide UNIVERSITY with strengthened educational capability in these fields, and MEMBER with the latest advances in technology.

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Design, Develop and Fabricate Primary and Siderostat Mirrors for BETTII Telescope

National Aeronautics & Space Administration (NASA)(6/04/15 - 5/31/16)

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Design, Develop and Fabricate Primary and Siderostat Mirrors for BETTII Telescope

Sponsor: National Aeronautics & Space Administration (NASA)

Start Date: 6/04/15

End Date: 5/31/16

Abstract

This proposal describes the research and development efforts needed to create high quality mirror surfaces on the rough machined and heat treated parabolic primary mirrors that are to be delivered to the PEC in May and assist in the design and fabrication of the two flat siderostat mirrors on the main frame of the telescope. a. The two primary mirrors are off-axis conic surfaces and to machine them on-axis is a complex process requiring the tool to follow a non-rotationally symmetric path to create the desired shape. The unique facilities at the PEC were designed for this type of fabrication. The cost of this phase of the proposed project will cost $61,535. b. The second phase of this proposal is to assist in the design and fabrication of the large flat siderostat mirrors used to direct the star(s) of interest onto the primary telescope mirrors. The details of machining the Siderostats is being proposed by the PEC. An estimate of the cost to modify the design and final machine the 2 Siderostats is $47,583. The total cost of the project is $109,118.

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