Feasibility of machine sewing wire reinforced asbestos and silica cloth plies of flexible heat shield curtain assembl

Dexter, J. N.

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SPACE DlViSlON LAUNCi i  CYSTEMS 3 BRANCH 
https://ntrs.nasa.gov/search.jsp?R=19670018179 2020-03-12T11:39:16+00:00Z
AERO-SP ACE biv isro~ 
LAUNCH SYSTEMS BRANCH 
DOCUMENT NO. T5-6556-10 b 
VOLUME -OF,-, 
TITLE EVALUATION OF MACHINE SEWN JOINTS FOR THE FLEXIBLE HEAT 
SHIELD CURTAIN 
I 
MODEL NO. A$T.URN V i  S-'eONTRACT NO., NAS8- 5608 4 
ISSUE NO. .m-/a. ISSUED, TO 
PREPAREDBY 
SUPERVISED B 
APPROVEDBY 
APPROVED BY 
APPROVEDBY 
/ REV. SYM. 
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a . a a . i n  s n a v  7 a4 
BOE I N G  
E. L. Clark 
DISTRIBUTION 
5- 7996 LS- 92 
J. N. Dexter 5- 7996 LS- 92 
P. E.’ Oster 5- 7354 LT- 49 
NASA -
F. McDaniel R- P&VE-VNR 
F. Uptagrafft R . P&VE-ME 
Scientific and Technical Information Facility 
Marshall Space Flight Center 
Huntsville, Alabama (Attn: MS-1P) 
Scientific and Technical Information Facility 
College Park, ’Maryland 20740 
rJ.0. BOX 33 
U M I . I W  NO. T 5 ~ 6 5 5 6 -  10 BoE/No I ?AGE .( i -  
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ABSTRACT i 
NO. T5-6556-10 
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J o i n t s  i n  the  wire  re inforced asbes tos  and s i l i c a  c l o t h  p l i e s  
of the  60B20508 f l e x i b l e  flame c u r t a i n  assembly are c u r r e n t l y  being 
mode by hand sewing. This i nves t iga t ion  covers r e s u l t s  of at tempts  
t o  machine sew these j o i n t s .  Resul ts  i nd ica t e  elkt  scceptab le  j o i n t s  
can be machine sewn i n  the s i l i c a  c l o t h  ply.  Machine sewlng was 
unsuccessful f o r  the  asbestos ply.  
KEY WORDS 
Asbestos Sewing 
F lex ib l e  Flame Curtain 
Machine Sewing 
Sewing 
Siiica Cloth Sewing 
REV.  SYM. - 
s - ~ o ~ - ~ E - z o  ORIO. 4/6B 
TABLE OF CONTENTS 
Distribution 
Change Record Page 
Revis ions Page 
Abstract and Key Words 
Table of Contents 
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5 .O 
Object 
Background 
Conc 1 us ions 
Recommendat ions 
Procedures and Results 
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5.1 
OBJECT 
The ob jec t  of t h i s  inves t iga t ion  was t o  determine the  
f e a s i b i l i t y  of  machine sewing t h e  w i r e  re inforced  asbestos  
and s i l i c a  c lo th  p l i e s  of t he  f l e x i b l e  hea t  s h i e l d  c u r t a i n  
assembly. 
BACKGROUND 
The j o i n t s  i n  the  wire-reinforced asbes tos  and the  s i l i c a  c l o t h  
p l i e s  of the  60B20508 base hea t  s h i e l d  c u r t a i n  assembly are 
cu r ren t ly  being sewn by hand. This t es t  was conducted a t  the 
request  of t he  In t e r s t age  and Heat Shield Group t o  determine 
the  f e a s i b i l i t y  of  machine sewing these  j o i n t s .  
sewing prove t o  be  f e a s i b l e  it could r e s u l t  i n  reducing manu- 
f ac tu r ing  c o s t s  with 8 r e s u l t i n g  c o s t  savinge. to  Boeing. 
Should machine 
CONCLUSIONS 
The results of  t h i s  i nves t iga t ion  ind ica t e  t h a t  i t  is f e a s i b l e  
t o  machine s e w  the  jo in t s  i n  t h e  s i l i c a  c lo th  using type 12 
Astroquartz  sewing thread which meet t h e  60B20508 drawing and 
the  60B32053 acceptance s p e c i f i c a t i o n  requirements.  The r e s u l t s  
a l s o  show t h a t  i t  i s  no t  f e a s i b l e  t o  machine sew the  j o i n t s  
in  the  wire  re inforced asbes tos  p ly  using the  metall ic f i lament  
th read ,  s ince  none of the j o i n t s  made during t h i s  i n v e s t i g a t i o n  
m e t  t he  requirements of 60B32053. 
/t 
RECOMMENDATIONS 
It i s  recommended tha t  t he  j o i n t s  i n  the  s i l i c a  c l o t h  ply of 
the  60B20508 cur ta in  assembly be machine sewn iisfng type 12 
Astroquar tz  sewing thread.  
It should be borne i n  mind t h a t  s i l i c a  c l o t h  has poor abras ion  
r e s i s t a n c e ,  therefore  provis ions  must be made t o  in su re  aga ins t  
abrasion o r  scuff ing damage t o  the  s i l i c a  c lo th  during machine 
sewing. 
PROCEDURES AND RESULTS 
The w i r e  re inforced asbes tos  and s i l i c a  c l o t h  p l i e s  of  t h e  
60B20508 f l e x i b l e  heat sh i e ld  c u r t a i n  assembly are  c u r r e n t l y  
befng made u s i n g  hand sewing W,hile t h i s  does produce c u r t a i n s  
of acceptable  qua l i ty ,  it i s  r e l a t i v e l y  expensive.  This 
program was performed a t  the  reques t  of the  I n t e r s t a g e  and 
Heat Shield Group to determine t h e  f e a s i b i l i t y  of  machine 
sewing the  j o i n t s  in these  p l i e s  i n  o r d e r i t o  e f f e c t  a c o s t  
savings i n  t h e  manufacture of the c u r t a i n s .  The request  f o r  
t h i s  i nves t iga t ion  spec i f i ed  t h a t  type 12 . b t r o q u a r t z  sewing 
thread (J .  P, Stevens and CO.) be used f o r  machine sewing the 
j o i n t s  i n  the  s i l i c a  c l o t h  and t h a t  types MF A 1  12/300/7Z and 
MF-B1 25/270/2Z meta l l ic  f i lament  threads (Groton Labora tor ies )  
be used t o  s e w  the  j o i n t s  i n  t h e  w i r e  re inforced  asbes tos .  
REV.  SYM. - 
s-40e-e5-n ORIO. 4/00 
fl'HZtN# I NO. T5-6556- 10 
PAGE 1 
5.2 
I 
5.3 
5.3.1 
The conclusions which can be made from the  r e s u l t s  of t h i s  
i nves t iga t ion  a r e  as follows: 
1. Machine sewing the j o i n t s  i n  t h e  w i r e  re inforced  
asbes tos  with t h e  m e t a l l i c  f i lament threads is  unacceptable 
because those j o i n t s  made per 60B20508 using t h e  MF-A1-12/ 
300/7Z thread did not  meet t h e  s t r eng th  requirements of 
60B32053. A l s o ,  i t  w a s  impossible t o  machine s e w  wi th  t h e  
MF'-B1-25/270/22 thread  because i t s  diameter w a s  too l a r g e  
t o  permit it t o  be fed through the sewing machine. 
2 .  Machine sewing the  s i l i c a  c l o t h  wi th  type 12 a s t r o q u a r t z  
sewing thread w i l l  produce j o i n t s  which meet t h e  60B20508 
drawing requirements and the  s t r eng th  requirements of t h e  
60B32053 acceptance s p e c i f i c a t i o n .  
Samples of wire reinforced asbes tos  c lo th  w & r e  cu t  so t h a t  
j o i n t s  could be made i n  which the w a r p  threads were p a r a l l e l  
f o r  some of the j o i n t s  and a t  45' f o r  t he  remainder t o  see i f  
f a b r i c  thread o r i e n t a t i o n  would have any e f f e c t  dur ing  machine 
sewing of the j o i n t s .  The f i r s t  a t t e m p t s  a t  machine sewing 
these  j o i n t s  wi th  the m e t a l l i c  f i lament th reads  were unsuccess- I 
f u l  because the diameter of t he  MF-B1-25/270/22 thread  w a s  too 
l a rge  and because of excess ive  breakage of t he  MF-A1- 12/300/72 
thread.  The thread breakage problem was solved by modifying 
t h e  Pfaff sewing machine by rep lac ing  i t s  725 rpm 0.4 horse- 
power motor with a 500 r p m  0.5 horse power motor. A l l  a t tempts  
a t  modifying the  sewing machine t o  feed the l a r g e  diameter 
fi lament thread were unsacessfu l .  
The sewn j o i n t s  made w i t h  the MF-A1-12/300/72 thread  ord t he  
p a r a l l e l  warp UUterialwere t e s t e d  f o r  breaking s t r e n g t h  a t  
room temperature and a f t e r  being subjected t o  t h e  temperature 
cyc le  shown i n  Figure I o r  Figure 11. The j o i n t s  were made wi th  
both f r e e  ends of the thread  knotted and.wfth t h e  f r e e  ends 
unknotted. The breaking s t r eng th  results a r e  shown i n  Table I. 
While the 60B32053 acceptance s p e c i f i c a t i o n  r equ i r e s  room 
temperature breaking s t r eng th  only f o r  t he  asbes tos  j o i h t s ,  
t h e  e leva ted  temperature tests were run to  determine what e f f e c t  
the e leva ted  temperatures would have upon the  i n t e g r i t y  of t h e  
me ta l l i c  f i laments .  Visual  examination of the  j o i n t s  a f t e r  t h e  
e leva ted  temperature cyc les  ind ica ted  near t o t a l  d e t e r i o r a t i o n  
of the fi laments as evidenced by a charred appearance and by 
crumbling when the  j o i n t s  were f lexed.  
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NO. T5-6556-10 
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5.3.1 (Continued) 
The room temperature breaking s t r e n g t h s  of t h e  m e t a l l i c  
f i lament th reads  were determined and a r e  shown i n  Table 11. 
The 0.010 inch diameter Inconel wi re  which is c u r r e n t l y  being 
used f o r  hand sewing the  asbes tos  j o i n t s  w a s  t e s t e d  and is 
included i n  Table I f o r  comparison purposes. 
1 
5.3.2 Machine sewn j o i n t s  were made i n  the high s i l i c a  c l o t h  using 
t h e  type 1 2  as t roquar tz  thread. The j o i n t s  were made using t h e  
s t i t c h i n g  spec i f i ed  Ln 60B20508 and t e s t e d  f o r  room temperature. 
breaking s t r e n g t h  per 60B32053. An average breaking s t r e n g t h  of 
23 Ib / in  of width was obtained f o r  t h e  t h r e e  samples t e s t e d .  
Since the ind iv idua l  values (20 l b l i n ,  24 ' l b / i n ,  and 25 l b / i n )  
a s  wel l  as the  average, were above the  minimum of 18 l b / i n  
required by 60B32053, machines sewing appears t o  be f e a s i b l e  
f o r  making the joints i n  the high s i l i c a  c l o t h .  The s i l i c a  
c l o t h  j o t n t s  were not t e s t e d  a t  e leva ted  temperature becaune t h e  
type 1 2  thread and the thread p resen t ly  being used f o r  hand 
sewLng these  joFnts a r e  made of e e s e n t i a l l y  the smne mate r i a l  
and t h e  hand dewn j o i n t s  have had no d i f f i c u l t y  in s u d n i n g  
t h e  thermal environment expected for t he  c u r t a i n  assembly. 
REV.  SYM. - 
. s-40a-a~-20  ORIO. we11 
, 
I 
TABLE I 
MACHINE SEWN WIRE REINFORCED ASBESTOS JOINTS 
MF-Al- 12/300/72 THREAD 
Minimum Acceptable Breaking Strength per  60832053- 
250 lb/ inch of width  
1 .  Both ends of  thread knotted 
Temperature 
Room Temperature 
After Figure I cyc le  
After Figure I1 c y c l e  
2 .  Both ends of  thread unknotted 
Temperature 
Room Temperature 
After Figure I cyc le  
ARfter Figure 11 cyc1.e 
Breaking Strength 
lbs/ inch of width 
194 
70 
90 
Breaking Strength 
lbs / inch o f  width 
115 
105 
86 
0 '  
-. 
TABLE I1 
SEWING THREAD ROOM TEMPERATURE BREAKING STRENGTH 
Mat e r i a  1 Breaking Strength (lbs) 
MF-A1 12/300/72 1.44 
Metallic Filament Thread 1.67 
MF-B1 25/270/2Z 4.75 
Metallic Filament Thread 5.00: 
0.010 inch Inconel wire 3.86 
4.18 
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S-408-89-29 ORIO. 4/88 
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a a /y' 


Evaluation of machine sewn joints for the flexible heat shield curtain

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