Crimp Tooling
Where Form Meets Function
Quality, cost, and throughput are key attributes for any production process. The
crimp termination process is no exception. Many variables contribute to the results.
Crimp tooling, defined here as crimpers and anvils, is one of those variables.
This paper will focus on defining key characteristics of crimp tooling and the effects
those characteristics may have on the production process.
Introduction
Quality, cost, and throughput are associated with specific measurements and linked to process variables. Crimp
height, pull test values, leads per hour, and crimp symmetry are some of the measures used to monitor production
termination processes.
Many variables affect the process such as wire and terminal quality, machine repeatability, setup parameters, and
operator skill.
Crimp tooling is a significant contributor to the overall crimp termination process. The condition of crimp tooling is
constantly monitored in production by various means. These means are often indirect measures. Crimp Quality
Monitors and crimp cross sections are methodologies that infer the condition of the crimp tooling. Visual inspec-
tion of the crimp tooling can be used
to check for gross failures such as tool breakage or tooling deformation which occurred as a result of a machine
crash. Continuous monitoring of production will help determine when
the process needs to be adjusted and the replacement of crimp tooling can be one of the adjustments that is
made.
Crimp tooling can a have positive effect on the quality, cost, and throughput of the termination process. High qual-
ity crimp tooling can produce high quality crimps with less in-process variation over a greater number of termina-
tions.
It is difficult to distinguish critical tooling attributes with visual inspection only. Some attributes cannot be in-
spected even by running crimp samples. This paper will present the reader with information that identifies key
crimp tooling attributes and the effect of those attributes on the crimping process.
Key Crimp Tooling Characteristics
There are four major categories of key characteristics for crimp tooling. These are:
Geometry and associated tolerances
Materials
Surface condition
Surface treatment
Each of these categories contributes to the overall performance of the production termination process.
tooling.te.comGeometry 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
set 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:
Cross Section Defining Crimp Width,
Crimp Height, and Flash
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 and A are, respectively, the initial cross-
W B
sectional areas of the wire and barrel before crimping.