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Cabling Splices


Cabling Splices

I am wondering what methods and techniques people are using for dealing
with splices in Pro/CABLING. We currently use a splice part that has 2
entry ports and is coin shaped with the same outside diameter as the
bundle the splice is in. We put the splice on a network location and
redefine the internal portions so the segment of network leaving the
splice exits the 2nd entry port. Any wires or cables going through the
original location now must go through the splice. These splices seem to
be unstable and cause no end of problems when flattening the harness. If
you revise the harness to add or remove a splice the flat harness will
fail at the splice location and will need to be re-flattened. This also
causes significant portions of the drawing fail. It's a huge loss of
time for something that should be pretty simple.

We are looking at an alternate technique where the splice part is much
smaller and is put in a "by-pass" section of network right next to the
main network. Only the spliced wires get routed to the splice and it
ends up being "hidden" by the bundle. On the flat harness the main
network is flattened and then 1 piece of network leading to the splice
is flattened so the splice can be assembled to it. This seems to allow
splices to be added/removed from the harness without causing major
failures with the flat harness and the drawing. It does seem to have
some problems with auto routing though. Even if the locations on the
splice are set to be secondary, wires unrelated to the splice sometimes
get routed through it.

I would like to know if others have tried this by-pass method and if it
has worked for them. I'm also interested in any other techniques that
people have tried.

Screw the splices!

Splices are notorious for piles of circular references and harness
flattening problems.
At the top level assembly, the circular references in our cables were
causing loops and
failures that caused the top assembly to take up to 6 hours to open.

There were many cables whose circular references were killed easily...
They had no splices.
There was one monster cable with multiple splices. It had 29 circular
references as well.
Because the cable was so difficult to flatten it became a sacred cow. No
one was ever
permitted to tweek it ever again! I started killing circular references
in the top assy,
there were over 120 of them... although there were only 67 being
reported. When I was done,
there were(any guesses?) 29 of them... all in that one cable. I created
a simplified rep
for top level assembly drawings that did not have that cable in it. Now
the top level
assembly opens in 20 minutes...

When I am routing a cable with splices, I attempt to keep the splices in
the backshells.
(good practice, they are easily checked and serviced that way)Also, I
only route to the
backshell itself. It's like magic - No splices to route ever! Some cases
do not allow
The splice to occur inside the backshell. These I fudge! Either route
different gauge wires
To the same location for purposes of calling out a splice, or just
continue routing to the
backshell if cable diameter is not an issue. If you really really really
want a visible
Splice on your drawing, you can always add a "label" feature and call it
a splice...

As long as your drawing and resulting cables are accurate, I am willing
to let my best
modelling practices slip a tad. This is especially true if you have any
concern over
maintaining your top level assembly... If you get enough splices, and
enough circular
References, your top assembly won't even open anymore, it will just loop
for an hour then crash.

Weighing risk to benefit... DEATH TO ALL SPLICES!!!

Everybody's gotta vent every once in a while...

Frederick Burke
Avionics Installations Engineer
Fire Scout VTUAV - Unmanned Systems
Northrop Grumman Corporation
858-618-7186 (FAX)

Thanks to all who replied to my Pro/CABLING splice query. The general
consensus was that splices just plain suck. I got few different ideas:

1. Make them with only 1 entry port. This allows them to be removed
from the flat harness with out it blowing up. Reflattening is still
required if you want to add one though.
3. Treat them as a regular connector component and don't use splice
functionality at all.
4. Place them on a "by-pass" section of network.

I really like #2 but I'm going to try some combination of #4 and #1
and/or #3. I don't have very high hopes though.

Anyone know why PTC hasn't bothered to address the splice issues? Seems
like it's a very basic requirement of what anyone would call a harness
modeling tool.

I wonder if this has been fixed in creo schematics 4.0?

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