Electronics > Projects, Designs, and Technical Stuff
Insulated crimp terminal diameter issue, KNIPEX / Molex / TE / AMP
mzzj:
--- Quote from: Benta on February 18, 2020, 09:02:33 pm ---
--- Quote from: mzzj on February 18, 2020, 08:42:51 pm ---
Bollocks. Proper combination has higher strenght than the cable itself.
Been there, measured on pull-out force tester..
--- End quote ---
Watch your language.
Apart from that, I've yet to see professionals using those "DIY-Supermarket" insulated connectors.
Automotive? Nope.
Industrial? Nope.
Consumer? Nope.
...
Please tell me in which professional equipment they're to be found.
--- End quote ---
Military? Aerospace? Does that count as professional?
Fold tab(F-crimp) connectors are for LOW COST mass production.
iroc86:
--- Quote from: Benta on February 18, 2020, 08:10:43 pm ---Functioning crimp connections use the "4-tab fold-in" design...
--- End quote ---
I would tend to agree. I haven’t had the best luck with the “4-tab” terminals (probably wrong crimper), but I’ve historically used the non-insulated F-crimp Molex Krimptite terminal with separate heat shrinking. Partly because I have a strange attachment to my ancient Molex/ETC crimper :), and partly because the joints are really reliable.
I haven’t started using the insulated terminals until relatively recently (see last paragraph below).
--- Quote from: mzzj on February 18, 2020, 08:42:51 pm ---Proper combination has higher strenght than the cable itself.
Been there, measured on pull-out force tester..
--- End quote ---
--- Quote from: Yansi on February 18, 2020, 08:46:28 pm ---And you can rest assured you are not going to pull the wire out of the crimp when properly crimped.
--- End quote ---
I also agree. Though hardly a scientific test, I tried pulling off each of those terminals in my original post. The smaller QD terminal slid right off, but I could absolutely not get the ring terminal to budge using pliers and pulling as hard as I could. Per Molex, the Insulkrimp terminals are rated for 50 pounds tensile strength with 14 AWG wire—it’s likely much greater in practice. I’ve gotta think that makes a secure electrical connection.
--- Quote from: Monkeh on February 18, 2020, 09:07:10 pm ---IME they're mostly seen in retrofit and small volume...
--- End quote ---
--- Quote from: mzzj on February 18, 2020, 09:23:43 pm ---Military? Aerospace? Does that count as professional?
--- End quote ---
This is just one data point, but I work for a “you definitely know them” research institution and my group often builds custom electromechanical systems for data collection and measurement. Everything has to be approved by our electrical safety officers prior to leaving the R&D lab. We almost exclusively use insulated crimp terminals on these one-off projects, and I’ve never seen one rig rejected due to the type of crimp terminal.
Considering that insulated terminals are widely used in our specialized applications at work, I decided to give them another try with a proper controlled-force crimp tool. The tricky part seems to matching the terminal to the correct crimper—not all are created equal, even though they look awfully similar.
WattsThat:
Measured a bunch of vintage Amp and T&B blue terminals, QD, ring and spades. All were 0.220 to 0.225.
The Amp terminals had matte blue bodies like the photo in reply #3, the T&B’s somewhat translucent blue, probably nylon.
All my red terminals measured all about 0.190.
Based on those diameters, I’d be crimping your blue QD’s in the red die.
Of course YMMV.
Benta:
--- Quote from: mzzj on February 18, 2020, 09:23:43 pm ---
Fold tab(F-crimp) connectors are for LOW COST mass production.
--- End quote ---
Allow me to correct your statement:
Fold tab(F-crimp) connectors are for LOW COST, RELIABLE mass production (eg, think 40-year old cars).
mikerj:
--- Quote from: Benta on February 18, 2020, 08:10:43 pm ---I tried those connectors out 25 years ago. They were useless then and they're useless now, no matter which brand or crimp tool you use.
The idea/design is faulty from the start and no serious engineer would ever use them.
Functioning crimp connections use the "4-tab fold-in" design, like these:
Insulation is done with tailored sleeves or heat-shrink tubing.
--- End quote ---
There are millions of these terminations in track side railway signalling equipment all over the world. I spent several years working for a company building these racks, and sectioned test crimps and wire pull tests were performed daily for each tool used.
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