8/13/2019 Low Cost Manufacturing Large Radomes JUL11

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Low Cost Manufacturing for Very Large Format, Low Observable Radomes

S2159-A-1&2 Approved for public release; distribution is unlimited.Rev A (JUL11)

Status: Phase 1 & 2 Complete

PROBLEM / OBJECTIVE

Large and very large aperture radomes (20 200 sq ft)represent a dramatic upscaling of conventionalmanufacturing. Defect opportunities for large aperture,

multi-function, structural radomes are unprecedented.Without further advances in manufacturing technologies,the production yield, cost, and delivery schedule is at risk.

Radome acquisition cost is reduced by improvingmanufacturing reliability to near 100% yield. ThisManTech project set out to help achieve this fabricationgoal by advancing process controls, inspection, and reworktechnologies for hand lay-up autoclave cured radomes.

ACCOMPLISHMENTS / PAY-OFF

Process Improvement:An automated Large Structure Inspection (LSI) systemwas used after each cure to inspect the laminates fordefects and determine the cured laminate thickness.

This on-the-mold inspection method decreases handlingrisks while enabling defect detection earlier in the valuestream. It also provides a dense data set that is used toaccurately determine the laminate thickness. Thicknesscontrol (i.e. Frequency Selective Surface layer spacing) isinstrumental in functionality of high frequency, lowobservable radomes. The LSI method used in conjunctionwith the radome Ply Calculator demonstrated the ability toachieve incremental and final thickness control of 3/8thick lay-ups within 3 mils.

The project also demonstrated multiple rework options forsolid laminate and A-Sandwich radomes, including resininjection, scarf repairs, and laminate remove and replacetechniques. In doing so, the project overcame thesignificant challenge of reworking composite panelscontaining embedded circuit layers while maintaining tighttolerance thickness control and RF performance.

In Phase 2, a reference table of structural knockdownsassociated with various defects and repair methods was

developed that will facilitate decisions regardingreparability of radomes regardless of defect type orlocation.

Also in Phase 2, the inspection procedure was scaled upfrom use on 3 x 4 panels demonstrated in Phase 1 to 9 x

9 panels. This scale up was demonstrated on a productionEHF radome for DDG-1000.

Implementation and Technology Transfer:Improved process flow via optimized debulk routines for

frequency and time under vacuum was transferred to theIFF and CEC2 programs. Likewise, in-process thicknesscontrol findings, including laminate measurements andmicro section results, were transferred to IFF, EHF, andCEC2. Use of the LSI system for thickness control anddefect detection was proven on panels up to 9 x 9.

Cosmetic and structural repair procedures for a variety oflaminate types are now available for production use. Insome cases, use on a production part first requiresmechanical analysis to determine knockdown. Theseknockdown tables were developed in Phase II.

Expected Benefits and Warfighter Impact:Improved process control, advanced defect detection, andeffective rework procedures have increased yield rates forhigh value radomes to near 100%. This has resulted in~$1.6M in savings and is expected to save over $3M onthe three DDG-1000 ships expected to be procured, whichwill in turn reduce radome acquisition costs and preventcostly integration schedule delays. The ManTechimprovements will benefit multiple DDG ship sets, as wellas multiple future ship platforms that utilize digital arrays.

TIMELINE / FUNDING

Phase 1 $990K Phase 2 $1.1MStart Date: Jun 2007 Start Date: Jan 2009

End Date: Oct 2009 Finish Date: Dec 2010

PARTICIPANTS

US Navy (PMS 500), Office of Naval Research,Composite Manufacturing Technology Center,Raytheon Advanced Products Center, and The AppliedResearch Laboratory at The Pennsylvania State University