[TriEmbed] Improvement over Molex crimp connectors?

[Shane Trent]

Rick,

Sorry for the delay, I wanted to have the crimpers in front of me to verify
the model number (63819-0900). I knew they were Molex branded but Molex has
hundreds of chassis and die combinations. The application is 12V lights/USB
on a bicycle and the current measured just under an amp on Friday but that
was lights only, no load on the USB socket.

Crimpers
http://www.molex.com/molex/products/datasheet.jsp?part=active/0638190900_APPLICATION_TOOLIN.xml&channel=Products&Lang=en-US

Terminals
http://www.molex.com/molex/products/datasheet.jsp?part=active/0039000038_CRIMP_TERMINALS.xml&channel=Products&Lang=en-US

18 ga wire has insulation listed at 0.010", measured diameter 1.72 mm

20 ga wire has insulation listed at 1/32", measured diameter 2.50 mm

So the 18 ga and 20 ga both fall within the Molex spec for maximum diameter
(3.10 mm) of the insulation (max cable diameter). But switching from the 20
ga to the 18 ga provided a big improvement in the reliability measured via
pull test. The terminals also much less fussy when crimping with the
smaller diameter 18 ga cable.

Other Resources I found when looking for specs on Molex crimping.

Molex Crimper Specification Sheet
http://www.molex.com/pdm_docs/ats/ATS-638190900.pdf

Molex Quality Crimping Handbook
http://www.molex.com/pdm_docs/ats/TM-638000029.pdf

Molex Industrial Crimp Quality Handbook
http://www.molex.com/pdm_docs/ats/TM-640160065.pdf


Thank you to everyone who send suggestions on or off the list!

Shane


On Fri, Oct 16, 2015 at 4:37 PM, Rick via TriEmbed <triembed at triembed.org>
wrote:

> Good afternoon Shane,
>
> Please pass along the crimp terminal part number(s), as well as the tool
> part number, and I'll see what I can dig up.
>
> Usually, the insulation is captured by the rear tabs, and the bare
> conductor by the shorter front tabs (with the contact mating surface
> considered the front).
>
> I've used the generic crimping tool as shown below:
>
>
>
> Please note this tool costs about $60.00 from Newark (you may find the
> price vary about 20% ... this is NOT the $8.95 tool).
>
> If you look at the crimp openings, one end is a concave "tooth" the other
> is an arc with a point in the middle ... or a double arc if you wish. The
> tabs on the crimp terminal go into the double arc, this forces the tabs
> around the wire and produce the double rounded top crimp. You must use the
> appropriately sized opening (marked in mm on the tool) for your crimp
> terminal; too large, and the wire will slide out of the crimped terminal,
> too small and you will deform the terminal (if you see shiny copper, or
> tightly folded tinned copper, you are using an opening that is too small.
>
> You can look at the data sheet for the individual crimp terminal, and it
> should tell you what size to crimp both the bare wire portion, and the
> insulation-holding portion (they can be different).
>
> You need to use firm pressure and ensure the tool closes completely (look
> below the hinge rivet and ensure the gap is closed the same as when there
> is not terminal in the tool.
>
> A proper crimp requires rather precise die, terminal, and wire dimensions;
> you are cold-forming the terminal and wire to exclude oxygen (called a
> gas-free connection) ... no oxygen, no oxidizing!
>
> If you still can't make sense of things, feel free to e-mail or call
> Molex; their applications engineering group is more than happy to help you
> select the correct terminals, housings, crimp tool and tool die size to
> use. I've been using my crimper for 15 years and have not had any issues,
> once I identify the proper die size and make sure I'm using the proper
> terminal for the wire size.
>
>
> Hope this helps.
>
> Regards,
>
> Rick
>
> - There are no shortcuts, just delays until you do the job correctly -
>
>
>
> On 10/15/2015 10:14 PM, Shane Trent via TriEmbed wrote:
>
> Hey TriEmbed!
>
> I have a client who is having reliability issues with their hand-crimped
> Molex connectors. They are using what appear to be genuine Molex crimpers
> and the proper wire for the terminal size (by wire gauge anyway, 20 ga))
> but are still having problems getting reliable connections. The wire seems
> to have larger insulation than I expect to see. Their 20 ga with insulation
> has a larger OD than my "house brand" 18 ga.
>
> Does anyone have a brand or type of connector that they like for
> hand-crimping in the 2 to 6 circuit sizes? These are low current circuits,
> expected to carry 4 amps or less. I am happy to treat for coffee if anyone
> has wisdom to share!
>
> Thanks,
> Shane
>
> --
> A blog about some of my projects.  http://fettricks.blogspot.com/
>
>
> _______________________________________________
> Triangle, NC Embedded Computing mailing listTriEmbed at triembed.orghttp://mail.triembed.org/mailman/listinfo/triembed_triembed.org
> TriEmbed web site: http://TriEmbed.org
>
>
>
> _______________________________________________
> Triangle, NC Embedded Computing mailing list
> TriEmbed at triembed.org
> http://mail.triembed.org/mailman/listinfo/triembed_triembed.org
> TriEmbed web site: http://TriEmbed.org
>
>


-- 
A blog about some of my projects.  http://fettricks.blogspot.com/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.triembed.org/pipermail/triembed_triembed.org/attachments/20151019/f3e8c953/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: adiffeci.png
Type: image/png
Size: 67286 bytes
Desc: not available
URL: <http://mail.triembed.org/pipermail/triembed_triembed.org/attachments/20151019/f3e8c953/attachment.png>