Geometry and Associated Tolerances
Terminals are designed to perform to specification only when the final crimp form is within a narrow range of
dimensions. Controlling critical crimp dimensions is influenced by many factors including:
• Wire size and material variation
• Terminal size and material variation
• Equipment condition
The final quality and consistency of a crimp can never be any better than the
quality and consistency of the tooling that is used. If other variations could
be eliminated, tooling can and should be able to produce crimp forms that
are well within specified tolerances. In addition, variation from one tooling
s
et to another should be held to a minimum. Crimp tooling features that are
well controlled and exhibit excellent consistency from tooling set to tooling
set can result in shorter setup time as well as more consistent production re-
sults.
Some critical crimp characteristics are directly defined by the tooling form
and are obvious. These include:
• Crimp width
• Crimp length
Other critical crimp characteristics can be related to several tooling form fea-
tures and/or other system factors. These may
be less obvious and include:
• Flash
• Roll, twist, and side-to-side bend
• Up/down bend
• Crimp symmetry
• Bellmouth
The following discussion focuses on two characteristics, crimp width and flash, as examples of how tooling can
affect crimp form. Similar arguments can be applied to the others.
Crimp Width
Crimp width is a good example of a feature that should be consistent and in control between different
crimpers of the same part number. The reason for this is quite straightforward. For a given terminal and wire
combination, it is necessary to achieve an area index, AI, which is determined by the terminal designer for op-
timal mechanical and electrical performance. Crimp height, CH, and crimp width, CW, directly affect achieving
proper AI. Area index, AI(as a percentage), is defined as:
where At is the total area of the wire and barrel after crimping. A
W
and A
B
are, respectively, the initial cross-
sectional areas of the wire and barrel before crimping.
Cross Section Defining Crimp Width,
Crimp Height, and Flash
