SITIS Archives - Topic Details
Program:  SBIR
Topic Num:  AF071-117 (AirForce)
Title:  In-Process Cure Monitoring of Specialty Material Coatings
Research & Technical Areas:  Air Platform, Materials/Processes

  STATEMENT OF INTENT: Process Improvement
  Objective:  Design and develop a sensor for measuring complex dielectric properties of specialty material coatings. Develop a methodology using the sensor for in-process cure monitoring of applied materials.
  Description:  Certain specialty material coatings are applied to aircraft through a paint spray process. This process involves multiple passes with a portion of the overall coating thickness applied during each pass, with time between to allow each layer to partially cure. The final performance of the coating is dependent on various factors, including overall coating thickness and material dielectric property, as measured post-cure. If the material is found to have the wrong electrical material performance characteristics following final cure of the material, it is a very burdensome process to remove the material from the aircraft. Having the ability to determine post-cure electrical performance before final cure would be advantageous by identifying bad material or incorrect application and allowing correction or immediate removal. The objective of this effort is to identify and develop a sensor and a non-contact sensor and process to monitor the material electrical properties during application and cure. The ideal sensor would be integrated with existing microwave inspection systems used by aircraft maintainers. The goal of the effort would be to provide a capability to identify incorrect, bad, or improperly cured material immediately after spray or during cure to facilitate corrective action or material removal. It is desired that the technology reach a Technology Readiness Level of 6 at the end of the Phase II effort (prototype demonstrated in a relevant environment).

  PHASE I: Identify an existing sensor design, develop a new sensor, integrate with existing microwave inspection systems, allow measurement of dielectric material properties. Design a method to correlate pre-cure to post-cure electrical performance. Demonstrate feasibility of design concept and methodology
  
  PHASE II: Fully develop and fabricate sensor and methodology, as demonstrated in Phase I, to inspect performance of applied specialty material coatings during the cure process. The prototype system is desired to be delivered to the Air Force at the end of the effort for further testing. This would also include a technical manual, a user manual, and all necessary hardware and software.

  DUAL USE COMMERCIALIZATION: Military application: This topic holds the greatest potential for meeting the technical needs of our warfighters for measuring complex dielectric properties of specialty material coatings. Commercial application: Tools and methods to measure and evaluate the cure processes applicable to structural applications, i.e., the monitoring of the cure of concrete support structures in bridges, and composite materials.

  References:  1. Survivability/Vulnerability Information Analysis Center website at: www.bahdayton.com/surviac 2. www.admc.aeat.co.uk/Background/Manufacturing/Manufacturing%20Issues%20MF/NDT_issues.shtml

Keywords:  aircraft maintainability, RF material systems, point inspection tool, cure monitoring, advanced sensor, dielectric properties evaluation

Questions and Answers:
Q: Is the coating applicaion process robotic or manual?
A: The bulk of the application process is robotic but some detailed areas are manually applied.
Q: Is the coating applicaion process robotic or manual?
A: The bulk of the application process is robotic but some detailed areas are manually applied.
Q: Does the proprietary microwave system monitor the coating or the substrate?
A: The coating.
Q: Please provide detailed information about:
1. The coating material, coating thickness of each layer, number of layers, substrate material and thickness;
2. Existing microwave inspection system
A: 1a. The coating material: polyurethane similar to MIL-C-85285C
1b. Coating thickness of each layer: approx 2-4 mils wet
1c. Number of layers: various
1d. Substrate material and thickness: composite and/or aluminum, thickness varies

2. Existing microwave inspection system: proprietary
Q: 1. Are you looking for an entirely noninvasive sensing method (beam backscatter, etc) or may the sensor be at least partially embedded in the coating? This would include an embedded sensor or a surface sensor which uses metal backing as groundplane (stripline, microstrip, etc).

2. What range of microwave frequencies are you considering?
A: 1. Noninvasive only.

2. Any portion of the electromagnetic spectrum is acceptable to determine cure and thickness.
Q: Does the proprietary microwave system monitor the coating or the substrate?
A: The coating.
Q: Please provide detailed information about:
1. The coating material, coating thickness of each layer, number of layers, substrate material and thickness;
2. Existing microwave inspection system
A: 1a. The coating material: polyurethane similar to MIL-C-85285C
1b. Coating thickness of each layer: approx 2-4 mils wet
1c. Number of layers: various
1d. Substrate material and thickness: composite and/or aluminum, thickness varies

2. Existing microwave inspection system: proprietary
Q: 1. Are you looking for an entirely noninvasive sensing method (beam backscatter, etc) or may the sensor be at least partially embedded in the coating? This would include an embedded sensor or a surface sensor which uses metal backing as groundplane (stripline, microstrip, etc).

2. What range of microwave frequencies are you considering?
A: 1. Noninvasive only.

2. Any portion of the electromagnetic spectrum is acceptable to determine cure and thickness.

Record: of