The document summarizes the development of wire insulation technologies for aerospace applications. Early materials like Kapton and ETFE had performance issues. Composite constructions introduced in the 1990s addressed these issues but Seamless PTFE technology provides further improvements. Seamless wire has advantages over other materials in properties like arc resistance, flexibility, weight reduction, and easier installation. It has become the preferred wire insulation solution in aircraft.

1. Airframe Wire Development

2. Engineering Driven Change
As aerospace engineers have responded to the performance
requirements of their customers, whether commercial or
military, innovation in the design and manufacture of
high temperature, high performance insulation systems
have been challenged to keep pace.
Improvements in space and weight savings without
sacrificing the thermal and mechanical performance of the
wire has been one of the key challenges.
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3. Advances in Wire Technology
• PVDF (1966)
• Peek (1970’s)
• ETFE (1970’s)
• Polyimide (1972)
• XL-ETFE (1978)
• Composites (1993)
• M22759/80A-/92A (1999)
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4. Engineering Issues Leading to Composite
Development
Prior to the introduction of earlier versions of the composite
constructions in use now, most aircraft were wired with
either a Polyimide (Kapton) or XLETFE insulation.
It was recognised that both of these insulation systems had
shortcomings and two separate development programmes
running concurrently led to the creation of the type of
composite construction used extensively today.
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5. Composite Development
• Two Development Programmes
– US Air Force CRAD – Wright Patterson AFB (1989-1991)
• Replacement for MIL-W-81381
• Comparative Study of 14 Candidates
– SPI – McDonnell Douglas (1996-1999)
• Hydrolytic Stability, Arc Propagation, UV Markability, Termination
Issues
• Acceptance by US Navy, Air Force, Army
• F/A-18EF, F-15, C-17, AH-64D
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6. Engineering Issues Leading to Composite
Development
• ARC Resistance (performance)
• Hydrolytic Stability (performance)
• Flexibility (shop handling)
• Notch Propagation (performance)
• Smoke Generation (performance)
• Insulation Weight and size (performance)
• Mechanical Toughness (performance + shop handling)
• Laser Marking (performance + shop handling)
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7. Performance Comparison
1974 1986 1999
M81381 M22759 M22759
Characteristic "Kapton" "XL-ETFE" "Composite"
Arc Resistance R G G
Hydrolytic Stability R G G
Flexibility R G G
Notch Propagation R Y G
Temperature Performance G Y G
Smoke Generation G R G
Insulation Weight G Y G
Mechanical Toughness G Y G
Laser Markability R G G
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8. MIL-W-22759 “Composite”
Abbreviations
Tape 1, applied with FP = Fluorocarbon Polymer
51-54% overlap PI = Aromatic Polyimide
PTFE = Polytetraflouroethylene
Tape 2, applied
with
51-54% overlap
Advantages
Thin Wall Insulation (Hook-Up)
Tape 1 .45 mil FP / .65 mil PI / .1mil FP Temperature Performance (260C)
Tape 2 2 mil Unsintered PTFE Mechanical Toughness
Total Nominal Thickness 5.8 mil Hydrolytic Stability
Arc Resistance
Smoke Generation
Normal Wall Insulation (Airframe) Flexibility
Tape 1 .5 mil FP / 1 mil PI / .5mil FP Low Weight
Tape 2 2 mil Unsintered PTFE Laser Markable
Total Nominal Thickness 7.6 mil
Disadvantages
Minor - Unique Blades
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9. SEAMLESS
First choice for Airframe Wire today!
“The look of extrusion with toughness of tape wrap all rolled into one.”
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10. Remember these?
• ARC Resistance (performance)
• Hydrolytic Stability (performance)
• Flexibility (shop handling)
• Notch Propagation (performance)
• Smoke Generation (performance)
• Insulation Weight and Size (performance)
• Mechanical Toughness (performance + shop handling)
• Laser Marking (performance + shop handling)
Lets see how SEAMLESS has raised the stakes!
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11. Wet Arc Resistance
• Reduces collateral
damage and PTFE
erosion
SEAMLESS
Standard composite Standard composite
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12. Hydrolysis Resistance
ELONGATION TO BREAK TREND PLOT FOR AGED DUPONT POLYIMIDE FILMS
AGING PARAMETERS 200 DEGREES CELSIUS, 100 % RH - PARR BOMB
DUPONT HIGH PERFORMANCE MATERIALS
JIM HEACOCK - PHIL LACOURT
FEBRUARY 2002
100
90
80
70
ELONGATION TO BREAK
60
(%)
50
40
30
20
100HN
10 65T
100T
0
0 5 10 15 20 25 30 35 40 45 50 55 60
AGING TIME
(DAYS)
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13. Flexibility
Flexibility (Stiffness & Springback)
CW SPI MDC97P0053
2.5
Stiffness (Ounces)
2
1.5 XL-ETFE
1 Composite
0.5
0
/44-22 vs /82-22 /33-26 vs /82-26
Material Tested
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14. Notch Propagation
Notch Propagation Results
(Wright Laboratory Report "WL-TR-91-4066")
(66% Notch Depth)
100
Cycles to Failure
80
60 XL-ETFE
40 Composite
20
0
/43-22 /43-22 /44-22 /44-22 /33-26 /33-26
/86-22 /86-22 /92-22 /92-22 /82-26 /82-26
NEW AGED NEW AGED NEW AGED
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15. Temperature Rating
• Composites 260oC over NPC conductor
M22759/80-92 require a Thermal Index
test at rated temperature for 10,000 hours
as a qualification test
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16. Smoke Generation
Optical Smoke Density (After 20 Minutes)
(Wright Laboratory Report "WL-TR-91-4066")
170.3
Optical Smoke Density (Ds)
150
109.7
100 XL-ETFE
Composite
50
1.7 1.3
0
/43-22 vs /86-22 /44-22 vs /92-22
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17. SEAMLESS Advantage: Weight
Seamless T Weight Reduction Light Weight Seamless T Weight Reduction
(Compared to Tefzel) (Compared to Polyalkene)
12.0% 7.0%
10.0% 6.0%
8.0% 5.0%
Percent
Percent
6.0% 4.0%
3.0%
4.0%
2.0%
2.0% 1.0%
0.0% 0.0%
6 8 10 12 14 16 18 20 22 24 10 12 14 16 18 20 22 24
Wire Gage Wire Gage
THE TAKE AWAY:
SEAMLESS weighs between 2 and 10% less than ETFE and 2
to 6% less than polyalkene insulated wires. With a
customer BOM an exact weight savings can be calculated.
Note: Comparison of Typical Maximum Weights
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18. SEAMLESS Advantage: Size
THE TAKE AWAY:
Cross linked ETFE SEAMLESS SEAMLESS requires 15-20%
less cross sectional area than
Cross Sectional Area Reduction an equivalent ETFE wire bundle;
SEAMLESS Composite v. X-Linked ETFE economizing space and increasing
25.0% routing density.
20.0%
Looking at a 22 AWG example,
15.0%
24 seamless wires can be routed
10.0%
in the same space as an equivalent
5.0%
0.0%
20 wire ETFE bundle.
26 24 22 20 18 16 14 12 10 8 6 4
AWG Size
Note: Comparison of Typical Maximum OD
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19. Mechanical Toughness
Dynamic Cut Through Results (Thin Wall)
(Wright Laboratory Report "WL-TR-91-4066")
60.0
Cut Through (Pounds)
50.0 M22759/44-22
40.0 (NEW)
30.0 M22759/44-22
(AGED)
20.0
M22759/92-22
10.0 (NEW)
0.0 M22759/92-22
23 70 150 200 (AGED)
Temperature (Celsius)
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20. Mechanical Toughness
Dynamic Cut Through Results (Normal Wall)
(Wright Laboratory Report "WL-TR-91-4066")
Cut Through (Pounds)
70.0
60.0 M22759/43-22
50.0 (NEW)
40.0 M22759/43-22
30.0 (AGED)
20.0 M22759/86-22
10.0 (NEW)
0.0
M22759/86-22
23 70 150 200 (AGED)
Temperature (Celsius)
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21. UV Laser Marking
66% Average contrast on white wire
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22. SEAMLESS in use
The introduction of the Thermax SEAMLESS
insulation system has clear advantages over
other wire types but what about it’s use on
the shop floor?
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23. SEAMLESS Assembly
No Edge
No Edge No edge lessens the
likelihood of catching
•Faster installation and the robust, tough
•Less Rework surface is les likely to
•Less Scrap get
scraped, scratched, or
damaged
THE TAKE AWAY:
SEAMLESS pulls easily and seamed ridges do not catch
during installation.
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24. SEAMLESS Advantage: Assembly
Standard Composite Technology
THE TAKE AWAY:
SEAMLESSTechnology SEAMLESS strips cleanly
minimizing assembly time
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25. SEAMLESS Advantage: Construction
THERMAX SEAMLESS Competitive Product
THE TAKE AWAY:
Layer –to-layer adhesion eliminates delamination and further
improves abrasion resistance.
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26. Conclusions
• Composite Construction Solved many
Technical Issues
• Seamless PTFE Technology showed further
improvements
– Reduces Handling and Installation Damage
– Improves UV markability/contrast.
– Improves Resistance to Wet Arc Propagation
Making SEAMLESS the first choice for Airframe wire
today!
22 Nov 2011