DVD-60C The Seven Sins of Wire Harness Assembly - IPC Training ...

DVD-60C Script
Once the machine is running and doing its job, it’s easy to let your mind wander and be thinking
of other things. But it’s important to monitor the machine and periodically check to make sure
that the wire strips are done properly.
If there are nicks or cut strands on the conductor, it usually means the cutting depth is too deep
and you should adjust the machine accordingly. Your company will let you know the maximum
allowable strand damage for the type of wire you are stripping. There can also be unacceptable
insulation damage from stripping. When the insulation is compressed, it usually indicates that the
rollers are too tight. Compressed insulation can possibly damage the conductor underneath and
affect the proper operation of the wire. Frayed insulation usually means that the cutting blades
are probably dull. If this is the case, blades should be changed.
Now let’s take a look at manual wire stripping. The biggest cause of conductor and insulation
damage occurs when using an inappropriate tool.
One of the safest manual wire stripping methods is the thermal stripper – which melts or softens
the insulation. Use your fingers to twist the insulation slug off in the direction of the wire lay.
Do not use the stripper to pull off the insulation slug as it can potentially damage the wire.
Mechanical strippers can also be used to safely strip the insulation from wires. The wire is
placed in the correct diameter hole for the correct strip length. The handles of the tool are then
closed. As the wire and tool are pulled apart, the insulation is stripped off.
Sin number 2 – Improper Harness Layout
The proper layout of the wires is critical for correctly connecting the harness inside the chassis of
the final product. That’s because specific lengths of wires need to break out of the bundle in
different locations in the chassis.
A lot can go wrong while forming the harness. If you’re not paying close attention, it’s easy to
route a wire in an incorrect location. It’s important that the correct wire is in the right position.
For example, if you were to route a smaller AWG wire in place of the correct larger wire, and it
gets connected inside the system, there may be damage to the wire and possibly the system.
Another big problem occurs when a wire is missing. That’s why it’s essential that you follow the
exact layout specified in the assembly drawing.
For complex wire harnesses, a template or form board is usually created to make the job easier.
The form board is the physical duplication of the assembly drawing – made to the exact same
scale as the finished wire harness.
In addition to following the layout shown in the assembly drawing, it’s important to follow the
correct sequence for laying out and routing the individual wires.
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