Making a detailed drawing of a complex harness?
Making a detailed drawing of a complex harness?
(OP)
Greetings,
This is more of a drafting question I suppose, but it fits the electrical bill.
Has anyone seen, know, or have any examples of a detail drawing of a complex electrical harness. In particular one with multiple layers of heat-shrink (or similair) sealing various soldered connections layered over one another?
Just curious as to how others have handled the situation on a drawing. Where you have individual splices that are heat-shrinked, that are then bundled into groups that are heat-shrinked over the top of that, which is then heatshrinked into bigger bundles, that is then all heatshrinked together (in that particular area) and is then covered with a braided loom (in that particular area)....
If that makes any sense...
Not really looking to get into why one would do such a thing, or alternative to heat-shrinking all that, but merely how to sufficiently detail the situation on a drawing when it is encountered.
As of right now, it seems easiest to do it with more of a work instruction, nevertheless there will need to be an end-result [detail] drawing of what is produced.
Thanks,
VS
This is more of a drafting question I suppose, but it fits the electrical bill.
Has anyone seen, know, or have any examples of a detail drawing of a complex electrical harness. In particular one with multiple layers of heat-shrink (or similair) sealing various soldered connections layered over one another?
Just curious as to how others have handled the situation on a drawing. Where you have individual splices that are heat-shrinked, that are then bundled into groups that are heat-shrinked over the top of that, which is then heatshrinked into bigger bundles, that is then all heatshrinked together (in that particular area) and is then covered with a braided loom (in that particular area)....
If that makes any sense...
Not really looking to get into why one would do such a thing, or alternative to heat-shrinking all that, but merely how to sufficiently detail the situation on a drawing when it is encountered.
As of right now, it seems easiest to do it with more of a work instruction, nevertheless there will need to be an end-result [detail] drawing of what is produced.
Thanks,
VS





RE: Making a detailed drawing of a complex harness?
There is no specific standard for the exact situation you posted that I'm aware of and most of that is "detail it for what works at your company"
This might include a step by step work instruction or multiview drawing,etc...
RE: Making a detailed drawing of a complex harness?
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RE: Making a detailed drawing of a complex harness?
The blueprint comes from the first article harness, which is built on the end product, then laid out on a big table and traced onto vellum.
Subsequent harnesses are built on the harness board, using precut and preterminated and premarked wires and precut lengths of sleeving, split loom, heatshrink, whatever.
There is usually a separate schematic,
and a separate wire list with wire lengths, terminations, and markings, for each and every wire.
I think modern CAD systems claim some ability to help in the process of generating a harness board drawing, but so far I haven't worked for an outfit that would cough up the money for a module like that.
Mike Halloran
Pembroke Pines, FL, USA
RE: Making a detailed drawing of a complex harness?
A multi-view regular 2d autocad drawing showing the harness at the various levels of its assembly process and sketching in the shrink tube is exactly how I would handle the OP's situation. And possibly a few notes on the drawing calling out any specific details that for some reason might not be able to be shown or grasped visually.
RE: Making a detailed drawing of a complex harness?
The SSP approach can fall apart when combined with outsourcing, unless carefully managed.
RE: Making a detailed drawing of a complex harness?
The shop doesn't need it.
The 3D graphics department only wants a fancy 3D image to put in the advertising
The final assembly dwg or final 3D assembly image 9for interference or routing purposes doesn't need it.
The BOM doesn't need it.
RE: Making a detailed drawing of a complex harness?
If you're making more than a few, then you need considerable detail. The harnesses may be made in a different facility than the end product, so quick fit checks against the end product are not possible. Harnesses may also be sold as service parts to end users, in which case you also have to generate shipping documents and installation instructions.
I've never seen a harness drawing in advertising; they're just too damn ugly, and harnesses are typically omitted from images for advertising, I'm guessing at least because their visual complexity might intimidate a potential customer.
Mike Halloran
Pembroke Pines, FL, USA
RE: Making a detailed drawing of a complex harness?
But, I'm reading between the lines.
RE: Making a detailed drawing of a complex harness?
Calculate the cable lengths of each major cable and cable bundle for weight control and CG location.
Maintain the minimum bend ratio of the individual power cables and the final cable bundles, while allowing room for expansion loops behind the consoles so the different individual consoles could still be pulled out of the frames,
Generate the 3D interference zones behind, above, and below each console so other stuff (piping and structure and other bundles) never hit the bundles already laid; and so new bundles could "fold and unfold" themselves without getting entangled in already-laid bundles or already-designed pipes.
And - finally - when changes were made, go back and do it all over again. 8<)
So, "routing" individual cables and cable bundles makes a lot of sense in certain circumstances, but modelling tie-wraps and shrink wrap inside tie-wraps and shrink wrap????
RE: Making a detailed drawing of a complex harness?
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RE: Making a detailed drawing of a complex harness?
But Modeling each shrink wrap? Doesn't seem warranted in my experience doing similar work.
RE: Making a detailed drawing of a complex harness?
And just how do you suppose the factory is going to know how to make it? And when someone bundles the wrong wires and causes problems with assembly, or leaves 1 or more layers of heat-shrink off, or does not get them overlapping correctly and it fills with water & cant drain, do I just argue with them about what I "think" it was supposed to be vs how they "think" it used to be?
Its a small mfg company (20 employees or so)... Its all hand-made, no automation. And unfortunately no peg-boards (whatever the harness fixtures are typically called). We make about 2x runs of 30 - 40 harnesses per year give-or-take.
I'm surprised by comments saying it doesn't need documented...? If it doesn't need documented, then it is not important, and if its not important then why do it? Get rid of it and same time and material...?
We have no requirements (govt, military or otherwise) that requires the documentation. It is the factory that requires information about what exactly they are supposed to produce. How else could expect it to be produced as intended?
Thanks,
VS
RE: Making a detailed drawing of a complex harness?
Various of our cable drawings detail the number of twists per foot for differential signals, how the shields are terminated, etc.
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RE: Making a detailed drawing of a complex harness?
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RE: Making a detailed drawing of a complex harness?
Make a couple views showing each main assembly step..
In autocad its simple as you don't have 3d models that you need to fudge/modify/work around.. Just lines/arcs.
RE: Making a detailed drawing of a complex harness?
We're not ISO, but I have created our own ISO type of standards. I'm in a company that had none of it and all the problems that go along with not having it... and I've been fighting the uphill battle the whole way. Been making good progress with it, but its a little too slow for my liking.
Would you happen to have any examples you could share?
At this point, I'm essentially creating a work instruction, not a drawing.
See the attachment for what I released. (note: half the info has been removed, tolerances, BOM, titleblock.etc)
Thanks,
VS
RE: Making a detailed drawing of a complex harness?
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