MEETING TO RESOLVE MLT-1540-4 REJECTION

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B05171A000400030063-1
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 3
• Document Creation Date: December 28, 2016
• Document Release Date: June 7, 2005
• Sequence Number: 63
• Publication Date: April 26, 1971
• Content Type: MEMO

26 April 1971
U. S. Government
STAT
0
STAT
MEMORANDUM OF UNDERSTANDING
Meeting to resolve MLT-1540-4 rejection
Prior to the start of the meeting, an MLT 1540-4 (S/N 002) was adjusted per
instructions from manufacturing. This unit and a E:::::? M-4 table were at hand
? during the meeting for first-hand evaluation of the characteristics under consideration.
Morgan B's letter was reviewed and briefly discussed. The most important
points under item 1 were interrelated and unique to the macroscope mensuration procedure.
An instrument was installed on the MLT and a sample film threaded to demonstrate the
operation and to clarify the areas of difficulty.
Play in the bridge-locking mechanism was cited as a major problem in alignment
of the target and reticle cross hair. Measurements of both tables were made to arrive at
a quantitative means of evaluation. Tests were performed with four and ten pound forces
applied to each bridge in t "X" and "Y."
STA
STAT
STA
4ff
1
~0
4# 10#
x .020 .
032 inches of
movement .022 .066 inches of movement
Y .029 .
077 inches of
movement .021 .055 inches of movement
Declass review by NGA/DoD
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Little significant difference was noted in the slack in each of the bridges. It
STAT was noted that the bridge was easier to move manually in the unlocked
condition requiring about 1 to 1-1/2 pounds of force to move. ThelMLT 1540 bridge STAT
movement, specified at 2 to 4 pounds, was measured to require 2 to 2-1/2 pounds in
the X direction and 3-1/2 to 6-1/2 pounds in the Y direction. High readings in the Y
movement were found due to an excessively tight drive chain. When this was readjusted
the Y movement required from 2-1/2 to 4 pounds and was considered to be in spec.
Another area of difficulty in operation was attributed to the X-Y bridge motor
drive. Whereas the MIM-4 has only manual positioning knobs for the bridge, the MLT
? 1540 is motorized to work in a speed range of 0 to 0.5 inches/sec. The total range of
speeds had been considered completely adequate for alI other applications since mostly
the upper speed Iimit was of concern in traversing. However, it was demonstrated that
even at the slowest speed (measured as 0.003 inches/sec.) it was difficult to position the
reticle cross hair precisely on a target. The total speed range, exceeding 150 to 1, was
not sufficient for this application.
Part of this is due to the nature of the measurement method being used. Commonly,
traversing measurements are made without an absolute zero reference position. Two
micrometer dial readings must be taken and the difference between them is the desired
value. To avoid arithmetic errors in subtraction, an alternative method is used. The
? micrometer is "zeroed" and the cross hair positioned precisely over one edge of the image
to be measured. The micrometer then gives a direct reading of the measured distance
when the traverse is completed. Successfully positioning the cross hair at the initial
point is obviously a critical part of obtaining accurate measurements.
In order to derive meaningful, quantititive parameters it was agreed to readjust
five additional MLT 1540-4 units and have the operators evaluate the performance of this
operation. Morgan B. agreed to furnish additional data to
bridge drive-speed limits and mechanical play tolerances in the locking system.
Alternatives such as a manual drive with or without motor assist or an overall reduction in
bridge drive speed, perhaps using a dual range system were also discussed.
engineering is to be contacted for possible other approaches to facilitate pLrecise positioning
of the bridge carriage for this application.
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STAT
The remaining items in Morgan B's letter were also examined on the unit with
the following agreements reached. Item 2 relates to screw heads and the Mode switch
protruding above the rear panel of the table surface. The knobs are currently being
replaced on all units by
at no cost to the customer. The screw heads were examined
as a possible source of damage to microscope objective lenses. In each instance, the
optics were recessed well beyond the screw head height so that no damage could result.
No changes are contemplated in this area. ,
Item 3 concerns the human engineering shape factor of the tilt and elevation
control switch handles. Initial production used a "bat" handle and a "paddle" handle for
? distinct differentiation. Later units were equipped with a truncated bat handle with
a skirt instead of the paddle handles. A distinguishable difference in feel was retained
STAT (in opinion). Whereas a sharp comer on the paddle switch which was a "knee
banger" had been eliminated Morgan B. expressed a strong preference for the paddle
switch with rounded corners. "I want my paddle switches" was Morgan's last statement on
the subject.
Item 4 was an overall criticism of_quality control. It was conceded
by everyone that considerdhle improvements over initial production were evident.
STAT Efforts on the part of _o achieve and maintain high quality standards were described
in a general discussion of the subject.
? Item 5 related to possible scratching of wide films with bad edge curl caused
by the 70 mm film guides. It was pointed out that the guides can be raised an additional
3j/16 of an inch to avoid any interference. greed to implement this change.
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