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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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How does crimping work?
The obvious answer is that you bend the metal of the connector so that
it holds the wire in place. This doesn't seem very satisfactory. Metal always retains some flexibility, even when bent beyond its yield point. No matter how hard you squeeze, there'll be some rebound when you release the pressure, which should result in a loose joint. After having had a bad experience trying to crip a lug some years ago, I recently faced the need to do this again. So I bought a moderately expensive ratchet based crimping tool. And, rather to my surprise, it actually works. But that doesn't answer the question of how. Sylvia. |
#2
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How does crimping work?
Sylvia Else wrote:
The obvious answer is that you bend the metal of the connector so that it holds the wire in place. This doesn't seem very satisfactory. Metal always retains some flexibility, even when bent beyond its yield point. No matter how hard you squeeze, there'll be some rebound when you release the pressure, which should result in a loose joint. After having had a bad experience trying to crip a lug some years ago, I recently faced the need to do this again. So I bought a moderately expensive ratchet based crimping tool. And, rather to my surprise, it actually works. But that doesn't answer the question of how. Sylvia. Usually the conductor is the same metal as the lug, it will have the same memory so if it is all squished it should stay there.Expanding and contracting in use at the same rate. (maybe) |
#3
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How does crimping work?
In article ,
F Murtz wrote: Usually the conductor is the same metal as the lug, it will have the same memory so if it is all squished it should stay there.Expanding and contracting in use at the same rate. (maybe) Most connectors are brass - to give more strength. Cable usually copper. -- *Why are a wise man and a wise guy opposites? Dave Plowman London SW To e-mail, change noise into sound. |
#4
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How does crimping work?
Dave Plowman (News) wrote:
In , F wrote: Usually the conductor is the same metal as the lug, it will have the same memory so if it is all squished it should stay there.Expanding and contracting in use at the same rate. (maybe) Most connectors are brass - to give more strength. Cable usually copper. crimp lugs are usually copper for copper wire |
#5
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How does crimping work?
In article ,
F Murtz wrote: Dave Plowman (News) wrote: In , F wrote: Usually the conductor is the same metal as the lug, it will have the same memory so if it is all squished it should stay there.Expanding and contracting in use at the same rate. (maybe) Most connectors are brass - to give more strength. Cable usually copper. crimp lugs are usually copper for copper wire Perhaps lug means some special terminal in the US? But most of the crimped terminals you come across - like say in a car or computer - are brass, but sometimes plated. -- *If you're not part of the solution, you're part of the precipitate * Dave Plowman London SW To e-mail, change noise into sound. |
#6
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How does crimping work?
On Mon, 30 Nov 2009 17:56:29 +0000 (GMT), "Dave Plowman (News)"
wrote: In article , F Murtz wrote: Dave Plowman (News) wrote: In , F wrote: Usually the conductor is the same metal as the lug, it will have the same memory so if it is all squished it should stay there.Expanding and contracting in use at the same rate. (maybe) Most connectors are brass - to give more strength. Cable usually copper. crimp lugs are usually copper for copper wire Perhaps lug means some special terminal in the US? But most of the crimped terminals you come across - like say in a car or computer - are brass, but sometimes plated. Cite a reference. |
#7
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How does crimping work?
"Dave Plowman (News)" wrote in message ... In article , F Murtz wrote: Usually the conductor is the same metal as the lug, it will have the same memory so if it is all squished it should stay there.Expanding and contracting in use at the same rate. (maybe) Most connectors are brass - to give more strength. Cable usually copper. **Only cheap, crappy crimps are brass. For copper wire, crimps should be copper. -- Trevor Wilson www.rageaudio.com.au |
#8
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How does crimping work?
In article ,
Trevor Wilson wrote: Most connectors are brass - to give more strength. Cable usually copper. **Only cheap, crappy crimps are brass. For copper wire, crimps should be copper. Depends on the use. I'd say the most common crimp terminals are in some form of spring loaded contact. And those tend to be made of brass because it is stronger than copper, so gives a better contact. -- *How do you tell when you run out of invisible ink? * Dave Plowman London SW To e-mail, change noise into sound. |
#9
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How does crimping work?
Dave Plowman (News) wrote:
In article , Trevor Wilson wrote: Most connectors are brass - to give more strength. Cable usually copper. **Only cheap, crappy crimps are brass. For copper wire, crimps should be copper. Depends on the use. I'd say the most common crimp terminals are in some form of spring loaded contact. **We're discussing CRIMP terminals. Like this: http://www.ami.ac.uk/courses/topics/...rmp/index.html Copper is the material, not brass. -- Trevor Wilson www.rageaudio.com.au |
#10
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How does crimping work?
On Nov 30, 3:26*pm, "Dave Plowman (News)"
wrote: In article , * *Trevor Wilson wrote: Most connectors are brass - to give more strength. Cable usually copper. **Only cheap, crappy crimps are brass. For copper wire, crimps should be copper. Depends on the use. I'd say the most common crimp terminals are in some form of spring loaded contact. And those tend to be made of brass Phosphor bronze or beryllium copper are the springy metals in common use (it may LOOK like brass...). A well-made crimp requires lots of thought about materials. Commonly, copper stranded cable works, a copper stranded cable with a couple of SS strands works, a copper solid cable of the same gage doesn't work... and don't even TRY to crimp to a SS cable with 'electronic' tools and lugs. Even the professionals get it wrong sometimes (Al wire is just fine with the right electrode paste and crimp lugs, but has a bad reputation). When amateurs get 'kits' and pliers at the dollar store, the result isn't pretty. |
#11
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How does crimping work?
On Mon, 30 Nov 2009 23:54:12 +1100, Sylvia Else
wrote: The obvious answer is that you bend the metal of the connector so that it holds the wire in place. This doesn't seem very satisfactory. Metal always retains some flexibility, even when bent beyond its yield point. No matter how hard you squeeze, there'll be some rebound when you release the pressure, which should result in a loose joint. After having had a bad experience trying to crip a lug some years ago, I recently faced the need to do this again. So I bought a moderately expensive ratchet based crimping tool. And, rather to my surprise, it actually works. But that doesn't answer the question of how. Because the wire bundle inside the crimp also rebounds? Interesting NASA paper that may shed some light: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20080013394_2008012901.pdf -- Rich Webb Norfolk, VA |
#12
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How does crimping work?
Rich Webb a écrit :
On Mon, 30 Nov 2009 23:54:12 +1100, Sylvia Else wrote: The obvious answer is that you bend the metal of the connector so that it holds the wire in place. This doesn't seem very satisfactory. Metal always retains some flexibility, even when bent beyond its yield point. No matter how hard you squeeze, there'll be some rebound when you release the pressure, which should result in a loose joint. After having had a bad experience trying to crip a lug some years ago, I recently faced the need to do this again. So I bought a moderately expensive ratchet based crimping tool. And, rather to my surprise, it actually works. But that doesn't answer the question of how. Because the wire bundle inside the crimp also rebounds? Interesting NASA paper that may shed some light: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20080013394_2008012901.pdf Interesting. And the FEM simulation vs measurement paragraph is somewhat impressive. -- Thanks, Fred. |
#13
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How does crimping work?
Rich Webb wrote:
On Mon, 30 Nov 2009 23:54:12 +1100, Sylvia Else wrote: The obvious answer is that you bend the metal of the connector so that it holds the wire in place. This doesn't seem very satisfactory. Metal always retains some flexibility, even when bent beyond its yield point. No matter how hard you squeeze, there'll be some rebound when you release the pressure, which should result in a loose joint. After having had a bad experience trying to crip a lug some years ago, I recently faced the need to do this again. So I bought a moderately expensive ratchet based crimping tool. And, rather to my surprise, it actually works. But that doesn't answer the question of how. Because the wire bundle inside the crimp also rebounds? It probably does, but the wide bundle is being subject to compression, whereas the connector is subject to both compression and bending. I'd expect a certain degree of unbending when the compression is released. Sylvia. |
#14
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How does crimping work?
"Sylvia Else" wrote in message ... Rich Webb wrote: On Mon, 30 Nov 2009 23:54:12 +1100, Sylvia Else wrote: The obvious answer is that you bend the metal of the connector so that it holds the wire in place. This doesn't seem very satisfactory. Metal always retains some flexibility, even when bent beyond its yield point. No matter how hard you squeeze, there'll be some rebound when you release the pressure, which should result in a loose joint. After having had a bad experience trying to crip a lug some years ago, I recently faced the need to do this again. So I bought a moderately expensive ratchet based crimping tool. And, rather to my surprise, it actually works. But that doesn't answer the question of how. Because the wire bundle inside the crimp also rebounds? It probably does, but the wide bundle is being subject to compression, whereas the connector is subject to both compression and bending. I'd expect a certain degree of unbending when the compression is released. Sylvia. There may be some expansion on release of the crimping pressure but the interior of the crimp junction is still under pressure. Regards ........ Rheilly P |
#15
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How does crimping work?
In article ,
Sylvia Else wrote: After having had a bad experience trying to crip a lug some years ago, I recently faced the need to do this again. So I bought a moderately expensive ratchet based crimping tool. And, rather to my surprise, it actually works. Having the correct crimp tool is essential for good results. -- Dave Plowman London SW To e-mail, change noise into sound. |
#16
Posted to aus.electronics,sci.electronics.repair
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How does crimping work?
Sylvia Else wrote:
The obvious answer is that you bend the metal of the connector so that it holds the wire in place. This doesn't seem very satisfactory. Metal always retains some flexibility, even when bent beyond its yield point. No matter how hard you squeeze, there'll be some rebound when you release the pressure, which should result in a loose joint. After having had a bad experience trying to crip a lug some years ago, I recently faced the need to do this again. So I bought a moderately expensive ratchet based crimping tool. And, rather to my surprise, it actually works. But that doesn't answer the question of how. Sylvia. The crimp wire squishes the corners of the pin so intensely, that a gas-tight connection forms, 4 for each winding. That makes a very reliable connection. But only if you do the wrap correctly. |
#17
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How does crimping work?
Sjouke Burry wrote:
Sylvia Else wrote: The obvious answer is that you bend the metal of the connector so that it holds the wire in place. This doesn't seem very satisfactory. Metal always retains some flexibility, even when bent beyond its yield point. No matter how hard you squeeze, there'll be some rebound when you release the pressure, which should result in a loose joint. After having had a bad experience trying to crip a lug some years ago, I recently faced the need to do this again. So I bought a moderately expensive ratchet based crimping tool. And, rather to my surprise, it actually works. But that doesn't answer the question of how. Sylvia. The crimp wire squishes the corners of the pin so intensely, that a gas-tight connection forms, 4 for each winding. I think you're referring to wire wrapping, which is something else. Sylvia. |
#18
Posted to aus.electronics,sci.electronics.repair
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How does crimping work?
In article ,
Sylvia Else wrote: The crimp wire squishes the corners of the pin so intensely, that a gas-tight connection forms, 4 for each winding. I think you're referring to wire wrapping, which is something else. It's the case too with a properly made crimp. Which very few are outside of the factory. There's no such thing as a universal crimp tool - each connector and cable requires a special for the very best results. -- *Time flies like an arrow. Fruit flies like a banana.* Dave Plowman London SW To e-mail, change noise into sound. |
#19
Posted to aus.electronics,sci.electronics.repair
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How does crimping work?
"Sylvia Else" wrote in message ... The obvious answer is that you bend the metal of the connector so that it holds the wire in place. This doesn't seem very satisfactory. Metal always retains some flexibility, even when bent beyond its yield point. No matter how hard you squeeze, there'll be some rebound when you release the pressure, which should result in a loose joint. After having had a bad experience trying to crip a lug some years ago, I recently faced the need to do this again. So I bought a moderately expensive ratchet based crimping tool. And, rather to my surprise, it actually works. But that doesn't answer the question of how. **A properly sized crimp (to the wire size), used with a quality crimp tool, used correctly, will ensure an excellent, gas tight connection. Better, in fact, than a soldered joint. -- Trevor Wilson www.rageaudio.com.au |
#20
Posted to aus.electronics,sci.electronics.repair
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How does crimping work?
Sylvia Else wrote:
The obvious answer is that you bend the metal of the connector so that it holds the wire in place. This doesn't seem very satisfactory. Metal always retains some flexibility, even when bent beyond its yield point. No matter how hard you squeeze, there'll be some rebound when you release the pressure, which should result in a loose joint. After having had a bad experience trying to crip a lug some years ago, I recently faced the need to do this again. So I bought a moderately expensive ratchet based crimping tool. And, rather to my surprise, it actually works. But that doesn't answer the question of how. Sylvia. BTW, I'm seeing huge variation between lug types (same colour - different brand). I bought some fully insulated ones - and could pull them all off with no difficulty. The ones I had in my stock from way back either failed by tearing the conductor - or had a strength exceeding mine, and didn't fail. At least there was some consistency - lugs out of the same box performed the same as each other. The crimping tool has a 'pressure' setting, but comes with no guidance on how to decide which pressure to use. Sylvia. |
#21
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How does crimping work?
In article ,
Sylvia Else wrote: BTW, I'm seeing huge variation between lug types (same colour - different brand). I bought some fully insulated ones - and could pull them all off with no difficulty. The ones I had in my stock from way back either failed by tearing the conductor - or had a strength exceeding mine, and didn't fail. If by fully insulated you mean the red blue and yellow types available in a variety of configurations - the colour determining the cable sizes catered for - they vary wildly in quality by maker, as do the crimp tools. Some seem to be made out of 'silver' foil. But even with the best, it's interesting to cut off the insulation after crimping and examine the quality of the crimp, especially at the bottom end of the range catered for. To me, the only really satisfactory crimp is the type that forms a heart shaped cross section after crimping - and those don't. At least there was some consistency - lugs out of the same box performed the same as each other. The crimping tool has a 'pressure' setting, but comes with no guidance on how to decide which pressure to use. -- *Ah, I see the f**k-up fairy has visited us again Dave Plowman London SW To e-mail, change noise into sound. |
#22
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How does crimping work?
Dave Plowman (News) wrote:
In article , Sylvia Else wrote: BTW, I'm seeing huge variation between lug types (same colour - different brand). I bought some fully insulated ones - and could pull them all off with no difficulty. The ones I had in my stock from way back either failed by tearing the conductor - or had a strength exceeding mine, and didn't fail. If by fully insulated you mean the red blue and yellow types available in a variety of configurations - the colour determining the cable sizes catered for - they vary wildly in quality by maker, as do the crimp tools. http://www.jaycar.com.au/productView.asp?ID=PT4525 The particular application is connecting to the terminals of an SLA, so these connectors have the advantage of minimising the scope for extraneous contact when they're in place. Shame they perform so badly on the pull test. Sylvia. |
#23
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How does crimping work?
In article ,
Sylvia Else wrote: If by fully insulated you mean the red blue and yellow types available in a variety of configurations - the colour determining the cable sizes catered for - they vary wildly in quality by maker, as do the crimp tools. http://www.jaycar.com.au/productView.asp?ID=PT4525 The particular application is connecting to the terminals of an SLA, so these connectors have the advantage of minimising the scope for extraneous contact when they're in place. Shame they perform so badly on the pull test. I too have seen these red terminals pull off a cable within their stated range. I prefer non insulated 1/4 in spade connectors that have a separate insulating cover. They have a better cable clamp too. This sort:- http://www.vehicle-wiring-products.e...ninsblades.php Made of brass, strangely. ;-) -- *What are the pink bits in my tyres? Cyclists & Joggers* Dave Plowman London SW To e-mail, change noise into sound. |
#24
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How does crimping work?
Dave Plowman (News) wrote:
In article , Sylvia Else wrote: If by fully insulated you mean the red blue and yellow types available in a variety of configurations - the colour determining the cable sizes catered for - they vary wildly in quality by maker, as do the crimp tools. http://www.jaycar.com.au/productView.asp?ID=PT4525 The particular application is connecting to the terminals of an SLA, so these connectors have the advantage of minimising the scope for extraneous contact when they're in place. Shame they perform so badly on the pull test. I too have seen these red terminals pull off a cable within their stated range. I prefer non insulated 1/4 in spade connectors that have a separate insulating cover. They have a better cable clamp too. This sort:- http://www.vehicle-wiring-products.e...ninsblades.php Made of brass, strangely. ;-) I've noticed what is probably a significant difference between the failed lugs, and the other type that seem OK. It lies in the length of the metal that gets crimped. The tool I'm using is one of these: http://www.dse.com.au/cgi-bin/dse.st...uct/View/T3535 It seems designed to crimp equally* two locations spaced apart. But the metal on the failed lugs is too short, and one side of the tool is just crimping plastic. [*] I emphasis "equally". Lest anyone think I've misunderstood, this is not a tool designed to crimp the conductor and insulator in one go. Sylvia. |
#25
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How does crimping work?
Dave Plowman (News) wrote:
In article , Sylvia Else wrote: If by fully insulated you mean the red blue and yellow types available in a variety of configurations - the colour determining the cable sizes catered for - they vary wildly in quality by maker, as do the crimp tools. http://www.jaycar.com.au/productView.asp?ID=PT4525 The particular application is connecting to the terminals of an SLA, so these connectors have the advantage of minimising the scope for extraneous contact when they're in place. Shame they perform so badly on the pull test. I too have seen these red terminals pull off a cable within their stated range. I prefer non insulated 1/4 in spade connectors that have a separate insulating cover. They have a better cable clamp too. This sort:- http://www.vehicle-wiring-products.e...ninsblades.php Made of brass, strangely. ;-) I've noticed what is probably a significant difference between the failed lugs, and the other type that seem OK. It lies in the length of the metal that gets crimped. The tool I'm using is one of these: http://www.dse.com.au/cgi-bin/dse.st...uct/View/T3535 It seems designed to crimp equally* two locations spaced apart. But the metal on the failed lugs is too short, and one side of the tool is just crimping plastic. [*] I emphasis "equally". Lest anyone think I've misunderstood, this is not a tool designed to crimp the conductor and insulator in one go. Sylvia. |
#26
Posted to aus.electronics,sci.electronics.repair
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How does crimping work?
In article ,
Sylvia Else wrote: If by fully insulated you mean the red blue and yellow types available in a variety of configurations - the colour determining the cable sizes catered for - they vary wildly in quality by maker, as do the crimp tools. http://www.jaycar.com.au/productView.asp?ID=PT4525 The particular application is connecting to the terminals of an SLA, so these connectors have the advantage of minimising the scope for extraneous contact when they're in place. Shame they perform so badly on the pull test. I too have seen these red terminals pull off a cable within their stated range. I prefer non insulated 1/4 in spade connectors that have a separate insulating cover. They have a better cable clamp too. This sort:- http://www.vehicle-wiring-products.e...ninsblades.php Made of brass, strangely. ;-) -- *What are the pink bits in my tyres? Cyclists & Joggers* Dave Plowman London SW To e-mail, change noise into sound. |
#27
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How does crimping work?
Dave Plowman (News) wrote:
In article , Sylvia Else wrote: BTW, I'm seeing huge variation between lug types (same colour - different brand). I bought some fully insulated ones - and could pull them all off with no difficulty. The ones I had in my stock from way back either failed by tearing the conductor - or had a strength exceeding mine, and didn't fail. If by fully insulated you mean the red blue and yellow types available in a variety of configurations - the colour determining the cable sizes catered for - they vary wildly in quality by maker, as do the crimp tools. http://www.jaycar.com.au/productView.asp?ID=PT4525 The particular application is connecting to the terminals of an SLA, so these connectors have the advantage of minimising the scope for extraneous contact when they're in place. Shame they perform so badly on the pull test. Sylvia. |
#28
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How does crimping work?
On Nov 30, 10:54 pm, Sylvia Else wrote:
The obvious answer is that you bend the metal of the connector so that it holds the wire in place. This doesn't seem very satisfactory. Metal always retains some flexibility, even when bent beyond its yield point. No matter how hard you squeeze, there'll be some rebound when you release the pressure, which should result in a loose joint. After having had a bad experience trying to crip a lug some years ago, I recently faced the need to do this again. So I bought a moderately expensive ratchet based crimping tool. And, rather to my surprise, it actually works. But that doesn't answer the question of how. Sylvia. The ratchet tool provides substantial mechanical advantage compared to many of the cheap tools, and therefore enormous pressure on the joint. With the right tool, the joint is squashed down by the exact amount, whereas cheap hand tools are more "hit and miss" as to whether you have applied the right pressure to them. the "die" is also a lot better on ones that I have seen, and probably designed to put the pressure in the exact right places at the right time during the crimp. (ie, more efficient use of the energy you apply with your hands) As the metal parts of the surface being crimped are squashed really hard by the tool, they probably heat up (compression causes heat, and metals expand with heat,), and then shrink as they cool, tightening on the wire ?. |
#29
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How does crimping work?
Another paper here of relevance
http://www.eee.metu.edu.tr/~ssedele/.../GOKCEN/45.pdf -- Regards Blue Remove ZX from email address to reply directly. |
#30
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How does crimping work?
And what's the view on the comparative effectiveness of swage
impact crimpers and hydraulic crimpers over ratchet crimpers? I find them both useful for automotive battery and similar large cabling but too cumbersome for smaller gauge wiring or close quarters as they need space and at least two free hands; indeed with the hydraulic I often need someone hold the cable and connector while I use two hands to crimp. And the swage impact crimper is a out of the car bench only tool. eg http://www.skygeek.com/ats-bs104.html for an impact swage crimper and http://www.skygeek.com/ats-bs104.html for a hydraulic crimper. I find with the right sized die they do seem to good job on even small terminals but if the size is even slightly wrong they tend to crush the terminal so its unusable. -- Regards Blue Remove ZX from email address to reply directly. |
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