Electronics > Manufacturing & Assembly
Low volume industrial cable assembly
tooki:
--- Quote from: coppercone2 on July 17, 2024, 11:19:26 am ---yeah IDK why the crimp tool is so hard to get in pneumatic if you tried to get a sheet metal guy to use a manual nibbler they would be like WTF
That part of the industry lagged. Of course, the problem is if someone just wants to do repairs, then you need manual or small electric tools. But for prototyping places.. its like under equipped without a benchtop crimper TBH
Like its kinda within the budget of even the smallest company. For the amount of BS it gets rid of , its cheap. Like lol they have a 3k expresso machine but its being crimped by archemedes with a cheater bar
There is something to be said about a pneumatic stripper too. I have the most expensive of the hand tools in my toolbox but their not fool proof. Its still made of plastic and if you switch wire insulation around (like you should during prototyping) you will run into some thickness or material that does not quite work well with the tool. The problem with that one, is that damaged strands and torn insulation get covered up EXTREMELY well by the work force so people don't know whats really going on there. Dead eyed liar saying the wire is "fine' after being mangled by a 20 year old harbor freight deal. Ok, maybe its fine for the code inspector on the job site you got your training on, but its not ok on the 30 awg teflon wire in a telemetry adapter box.
So basically I noticed, with the hand strippers, I can do a good job, but its way slower. You need to frequently readjust the tool with test wire. Within only 3 months I noticed none of the settings I had are working anymore. If you care enough to look at your wire under a microscope, you will desire the nice stable pneumatic stripper (one of the things I miss from a factory). Something about the momentum makes it tear off the wire insulation nice and clean without having to get too deep in the insulation. The hand tool is more likely to do damage IMO.. I get a little worried doing multi conductor cables that are fine with it. If you only got 7 strands, and its thin gauge, I can't accept a nicked strand there in something I deem reliable.... its bearly strong enough if its made perfectly... but thats a thing you run into with signals that have to be compact IMO. The little matchbox strippers are also just as problematic as the self adjusting ones if you expect it to have a long tool life. seems like a false economy in some senses.. you can get by of course, but its a bit of a pain
I thought I could have people do some of the labor like distribute it, but with the hand stripper, its like.. your just gonna end up nicking one of the wires unless your good because the tooling seems to drift. so i stopped trying to make that part into a team activity. With the pneumatic one you could get the desk jockys to help out if its set right ;D
--- End quote ---
I feel like you're a bit hung up on pneumatic specifically, when the real goals are a) hand tools that are easy to use, and b) automatic tools (regardless of technology).
Crimp tools vary widely, even for a specific type of contact. For example, at work I have two different Knipex hand crimpers for insulated terminals. They use identical dies. But one is the slightly cheaper, more compact handle design, the other is larger and slightly more expensive. I far prefer using the latter, because its longer handles and different lever arrangement result in it requiring significantly less hand force to operate. (And its jaw action is closer to parallel.)
Or how Molex has made many, many, many different hand tools for the Mini-Fit Jr. contacts over the years, at various price points. The current "PremumGrade" ones (= the non-budget hand tools that cost around $400), with parallel-action jaws, made by Pressmaster, need far less hand force than more traditional tools.
This huge range of performance is all with purely mechanical hand tools.
Then there are the partly automatic hand crimping tools that use reeled contacts, eliminating the need to insert individual contacts in the tool. These tools are designed for medium volumes that are too tedious and unergonomic for the simpler tools.
Then you get to benchtop crimpers that are still operated by humans (i.e. you insert the wire manually). And finally, fully-automatic machines that feed, cut, strip, and crimp the wire without human intervention.
Similarly, with wire strippers there are many different types, from the cheapest manual strippers, to automatic manual strippers, to benchtop machines, to fully automatic unattended ones.
At work, a different department (where I used to work) has two benchtop strippers, one using V-cut blades (good for most kinds of "ordinary" insulation and some more challenging ones), and one rotary coaxial stripper, which uses flat blades spinning at high speed. It's primarily intended for step-stripping coaxial cables (i.e. you program in the various cut depths and strip lengths, then you insert the wire, press the pedal, and it does it all in one go), but it's also great for challenging insulation like Kapton.
I TOTALLY understand your frustration with people who don't "see" quality, and think crap is "fine". Especially the ones who don't see flaws even once told what to look for. I think this is why military and aerospace have such strict requirements not only on workmanship standards, but on which tooling is allowed, and how it must be maintained. It has to be made idiot-proof, especially against what I consider to be "willful idiots" who dismiss what they are taught.
coppercone2:
yeah idk the ones I like are pneumatic they really have some momentum for stripping wire and punching stuff, if you can get them its great
I think the parts are under a different 'regime' with the high speed air powered blade and grabbers / hammers
theoretically slower is better for crimping, but I think faster is better for stripping because it like tears the insulation beautifully. It does not seem to elongate the wire insulation because its so fast... but even with the crimp, there might be a benefit to that really fast point deformation, perhaps the rest of the structure that is not designed to bend, bends less and it stays geometrically better. Old papers on crimp research showed that metal held under pressure does behave a bit differently if you "hold" the crimp longer.. but proving anything there would take ALOT of money and work.
That stupid little... turtle neck.... can form on wire that is stripped sometimes. I feel like I never saw it with the air strip. Like the very thin 0.5mm tall deformed pulled insulation thing. I thought that the machine is so blazing fast that even if its not set 100%, it seems to like tear that bit off, instead of letting it stretch out. It won't happen with silicone insulation but it can happen to PVC and PTFE and probobly ETFE. Its kind of like pulling whipped cream, the little "santa hat".
tooki:
Maybe you need to share exactly what model of pneumatic stripper you mean. (Because a whole lot of wire stripping machines, using disparate methods for doing the stripping, use compressed air for some part of the machine’s operation.)
“Slower is better” may be true for crimping, but without doubt, modern crimp contacts are designed for very quick termination. In volume, crimping machines just whack down the jaws with full force. Proper contact positioners and die geometry ensure that the contact is not deformed or bent during crimping.
Turtleneck: are you referring to edge flash? Refer to sections 1.01 and 1.02 of the NASA inspection standards here: https://workmanship.nasa.gov/lib/insp/2%20books/frameset.html
(Sorry, there’s no way to link to a section while also maintaining the navigation pane.)
Speaking of stripping, I’ve got a few PUR (polyurethane) power cables to terminate next week. What a goddamn PITA they are… I did a few this week, super annoying because the cable in question has PUR-insulated conductors as well, and those use two layers, one of softer PUR, and a thin layer of harder PUR in direct contact with the copper. None of my wire strippers can reliably strip the conductors, they mostly remove the soft PUR but leave the thin layer of hard PUR, which adheres quite tightly. :/
In contrast, yesterday I had to make an RG-196* BNC cable using the automatic rotary coax stripping machine at the other department at work. What a glorious doodad: after programming the strip depths and lengths, you insert the cable, press the pedal, and a few seconds later the cable is perfectly stripped with sub-mm accuracy, with jacket, shield braid, and dielectric all cut back to precise dimensions for the plug.
*RG-196 is essentially a variant of RG-178 with a PTFE jacket instead of FEP.
coppercone2:
Yeah Edge flash. I don't know the name of the machine it was a while ago, but it had a micrometer adjustment for the blade and basically a little pressure switch that when you poked a lever with the wire it would actuate the stripping mechanism, and it just ran on a air hose at some modest pressure (50psi +)
that is a really nice website compared to the PDF versions
price around $5k
Edge flash is absolutely annoying and if you get a very thin one, it can get into the crimp and probobly wreck havok. Even now for lab cables I write in my procedures that you need to do a 360 degree inspection after trimming to wire to verify the insulation is cut OK.. and with the hand tools and general process quality I see now, I would be generally disappointed if someone followed my procedures and did not inspect the stripping. I think the high end hand tools are pretty good at not nicking the wires, but they can do edge flash. So people are like "oh it wont nick with this" but they don't think if you will get a curl of insulation into the crimp area!
And usually we get some one that is good at wire nuts and IDC type crimps, so they have zero concern for insulation, since those processes will shred/ignore it.... so you really need to be careful with wording and expectations of quality.
The other problem is that people seem to watch to reach for a exacto to clean it off. I think the only good way is to use very flush cutters . I don't wanna see knives near the insulation of fine cable.
For PUR, I don't know. I imagine its very gummy. For coaxial cable insulation, especially fep film, the machine is basically essential if you don't want to clown around. I have RG405? FEP insulated cables and the best tool I found for that is the cheap coaxial stripper, the one piece with a plastic flex hinge with a razor blade embedded in the plastic. Expect to ruin a few feet by nicking the braid before you find the exact position that it works. I would be embarrassed to show this 'method' at work, its basically guess work. Its thin and the cable is never strait. I think the cable stripper machine pulls it a bit so its taught and then it can cut, but if you do it by hand... your basically always cutting on a elbow piece. :-- . Thermal would be the only budget way to get at this cable 'professionally' without looking like your widdling sculptures on the front porch of the cabin in the rocking chair with a double barrel and a xxx jug.
and to add insult to your injury, I suspect PUR insulation would make a lumpy mess if you try to thermal strip it lol
Navigation
[0] Message Index
[*] Previous page
Go to full version