DETERMINATION OF THE FORCE REQUIRED TO BEND FILM 180 DEGREES OVER DIFFERENT RADII OF CURVATURE

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B04747A002800030001-8
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 20
• Document Creation Date: December 28, 2016
• Document Release Date: December 8, 1999
• Sequence Number: 1
• Publication Date: February 1, 1965
• Content Type: REPORT

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DETERMINATION OF THE FORCE REQUIRED
TO BEND FILM 180 DEGREES
OVER DIFFERENT RADII OF CURVATURE
February 1965
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submits this
report in compliance with Item 4.2 of the Development
Objectives of Contract 974. This report should be
read in conjunction with Report 974-000 of which it
forms a part.
Approved:
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This report presents the results of investigations
conducted to determine the force required to bend film
180 degrees over different radii of curvature. The tests
were carried out as part of a series necessary to estab-
lich design criteria essential to the development of the
liquid/air bearing concept of film processing.
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FIGURE
PAGE
1
SO-1188
9-1/2-Inch Thin-Base Film
3
2
SO-1188
5-Inch Thin-Base Film
4
3
SO-1188
70MM Thin-Base Film
5
4
SO-1188
35MM Thin-Base Film
6
5
Type 8430
9-1/2-Inch Medium-Base Film
7
6
Type 8430
5-Inch Medium-Base Film
8
7
Type 8430
70MM Medium-Base Film
9
8
Type 8430
35MM Medium-Base Film
10
9
Leader
9-1/2-Inch Heavy-Base
11
10
Leader
5-Inch Heavy-Base
12
11
Leader
70MM Heavy-Base
13
12
Leader
35MM Heavy-Base
14
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In a liquid/air bearing type of film processor, the objective
is to transport the film from the load end to the takeup end without
mechanical contact between the film and the machine. This objec-
tive is attained by providing stationary sleeves in place of rollers
in and between the tanks. Air, or the fluid in the tanks, is pumped
into the sleeves and ejected at sufficient velocity and pressure to
form a continuous cushion between the film and the bearing. The
film is transported over this continuous cushion free of mechanical
handling and with low tension on the film. Two main criteria are
necessary to determine the cushion loads and capstan torque require-
ments: (1), the coefficient of friction of the film (film drag load)
and (2), the additional tension required to bend the film around the
bearings. This report determines the values of the latter parameter.
SECTION 2 - TECHNICAL DISCUSSION
To obtain the values of the loads, a framework was con-
structed in which rollers were mounted as required. The diameters
of the rollers used were 1/2, 1, 2, 3, and 5 inches. These diameters
were selected as those giving a sufficient number of points for the
plotting of a curve for each film thickness, A 15-inch length of each
film sample was hung over each diameter of roller and weights were
added until the film touched the roller over an angle of 180 degrees.
New, dry, unprocessed film was used. The film tested was in
35mm, 70mm, 5-inch, and 9-1/2 inch widths, with base thicknesses
of 0.00257, 0.0056, and 0.0085 inch.
The results obtained show that each test yielded a real half
of a hyperbola, and that the break in the curves occurred for a diameter
of 5 inches or greater.
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SECTION 3 - CONCLUSIONS
Based on the dry film values obtained, it is concluded that
capstans and bearings should be designed with a minimum diameter
of 5 inches to minimize total film tension and maximum bearing and
capstan loads. Where circumstances permit, bearings of even larger
diameter should be used.
To give a design example, a processor using thirty-seven
1-inch diameter bearings (assuming use of 2.57 mil thin-base film,
Figure 2-1) would require a total force of 153.6 grams x 37, or
12.5 pounds. Selection, in the same machine, of 5-inch diameter
bearings would result in a total force of 17.5 grams x 37, or 1.43
pounds. This produces a significant reduction in film tension,
bearing cushion loads, and drive capstan torque.
2
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Q II
0
S.O. 1188 9-I/211X I511 THIN-BASE FILM
2.57 MILS - THICKNESS OF MATERIAL
UNPROCESSED
NOTE'
WEIGHT OF MATERIAL NOT INCLUDED
207 7g
IN THE 1800 PULL DOWN WEIGHT
10.9 g =WEIGHT OF MATERIAL
153.68
i
I
i
fI
98 0g
71.78
17.5g
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LQ
153.9g
NOTE -
WEIGHTOFMATERIAL NOT INCLUDED
IN THE 180? PULL DOWN WEIGHT
5. 6 g = WEIGHT OF MATERIAL
80.0g
4
0 59.Og
26.6 g
ZOg
S.O. 1 188 5" X 15" THIN-BASE FILM
2.57 MILS - THICKNESS OF MATERIAL
UN PROCESSED
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NOTE:
WEIGHT OF MATERIAL NOT INCLUDED
DOWN WEIGHT
?
PULL
IN THE 180
3 1 g = WEIGHT OF MATERIAL
90 29
65.6 g
49.3 9
5
20 7g
5.8g
5
DIAMETER OF ROLLERS
S.O. 1 188 70 MM X 15" THIN -BASE. FILM
2.57 MILS -THICKNESS OF MATERIAL
UNPROCESSED
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5
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5
3"
DIAMETER OF ROLLERS
S.O. 1188 35 MM X I51' THIN - BASE FILM
2.57 MILS - THICKNESS OF MATERIAL
UNPROCESSED
53.9g
NOTE
WEIGHT OFMATERIAL NOT INCLUDED
IN THE 180? PULL DOWN WEIGHT
1.5g = WEIGHT OF MATERIAL
II
41.6 g
187g
9.4 g
46g
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756.6g
NOTE:
WEIGHT OF MATERIAL NOT INCLUDED
IN THE 180? PULL DOWN WEIGHT
17.9 g: WEIGHT OF MATERIAL
292.68
4
1214
148.98
77.88
0
400
TYPE 8430 9 - 1/ 2" X 15" MED -BASE FILM
5.6 MILS - THICKNESS OF MATERIAL (BASE ONLY)
UNPROCESSED
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NOTEI
WEIGHT OF MATERIAL NOT INCLUDED
IN THE 180?PULLDOWN WEIGHT
9 5 g =WEIGHT OF MATERIAL
TYPE 8430 5" X 15" MED-BASE FILM
5.6 MILS-THICKNESS OF MATERIAL
UNPROCESSED
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252 6g
NOTE
WEIGHT OF MATERIAL NOT INCLUDED
IN THE I BO?PULL DOWN WEIGHT
7.0 g WEIGHT OF MATERIAL
140.4 g
I
I
97.8g
65.29
-- -
15.3 g
TYPE 8430 70M M X 1511 MED -BASE FILM
5.6 MILS -THICKNESS OF MATERIAL
UNPROCESSED
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 amomw mumm wm. - anow rr sommaw ano - Orr wwi ctrl i- bond um~ -
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45
DIAMETER OF ROLLERS
TYPE 8430 35 M M X 1 511 MED - BASE FILM
5.6 MILS-THICKNESS OF MATERIAL
UN PROCESSED
161.9g
NOTE.
WEIGHT OF MATERIAL NOT INCLUDED
IN THE 1800 PULL DOWN WEIGHT
2.6 g = WEIGHT OF MATERIAL
III 2 g
72.09 41
55.79
1229
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0
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NOTE '
WEIGHT OF MATERIAL NOT INCLUDED
I N THE 180 0 PULL DOWN WEIGHT
24.7g = WEIGHTOF MATERIAL
LEADER 9-1/211 X 15" HEAVY-BASE FILM
08.5 MILS -THICKNESS OF MATERIAL
UNPROCESSED
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NOTE: I
WEIGHT OF MATERIAL NOT INCLUDED
IN THE 180? PULL DOWN WEIGHT
13.0 g = WEIGHT OF MATERIAL
DIAMETER OF ROLLERS
LEADER 5" X 15" HEAVY-BASE FILM
08.5 MILS -THICKNESS OF MATERIAL
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0 1/2"
NOTE.
WEIGHT OF MATERIAL NOT INCLUDED
IN THE 1800 PULL DOWN WEIGHT
10.0 g = WEIGHT OF MATERIAL
CD LEADER 70MM X 15" HEAVY-BASE FILM
08.5 MILS -THICKNESS OF MATERIAL
UNPROCESSED
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NOTE:
WE,GHTOF MATERIAL NOT INCLUDED
IN THE 1800 PULL DOWN WEIGHT
3.6 g = WEIGHTOF MATERIAL
381.59
215,9g
J
0
131.99
IOOg
0
67.98
0
0
LEADER 35MM X 15" HEAVY-BASE FILM
08.5 MILS - THICKNESS OF MATERIAL
UNPROCESSED
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