TM 1-1500-204-23-11
5-7. LAMINATE ORIENTATION CODE. As men-
is to select the 0 degree in the same direction as the
tioned in paragraph 5-6, to ensure the ibers in an
main load, the iber in the top ply or the dominate
advanced composite laminate perform their function
iber direction in the laminate. When a set layup is
of carrying load and providing part stiffness, it is
to be followed, system speciic technical manuals or
essential that the ibers be properly oriented. In
drawings should be consulted for setting the reference
addition, the individual plies in a laminate must be
direction.
placed in the proper stacking sequence to ensure the
required laminate mechanical properties are obtained.
c. Angles. The angle of each ply or lamina rep-
The laminate orientation code was created to simply
resents its orientation in degrees between the ibers
and clearly describe the layup of a laminate.
in that ply (lamina iber direction) and the reference
direction of the laminate.
a. Reference Plane. The reference plane is
selected as either the bottom or top ply of the
d. Ply Orientation Convention Symbol. The ply
laminate for the laminate orientation code. When the
orientation convention symbol, or "warp clock" as it
laminate is symmetrical about the midplane, selection
is often referred to, is used in drawings to indicate
of either the top or bottom ply as the reference plane
the reference, or 0 degree direction and to coordinate
will yield the same results.
the part drawing to a ply table or shorthand code
like the ones shown in igure 5-15.
b. Reference Direction. Selection of the reference
direction or 0 degree is arbitrary. Standard convention
Figure 5-15. ASTM Standard for Measuring Ply Angles
(1) The ASTM-D-6507 and CMH-17 standards
of the part drawing at the location(s) where
measure positive angles in the counterclock-
the part is to be inspected during the man-
wise direction when looking at the mold sur-
ufacturing process. Since iber directions
face, or tool. This is commonly referred to
can change, sometimes dramatically when
as the counter-clockwise (CCW) warp clock
composite materials are applied to parts with
and can be thought of as looking from the
complex geometries, it is not uncommon to
IML, or "bag side" of the part, outward as you
see drawings with numerous warp clocks
would when manufacturing a part and should
illustrated on the part.
be placed on the inside, or bag side surface
