Crimping molex connectors

Hi all,

I have built Generation 7 electronics for use with my Prusa mendel - and it's working out ok so far. The Generation 7 electronics (like most of the electronics solutions I guess) uses Molex connectors for the stepper motors, heaters, and thermistor connections. Because the crimping tools for Molex connections are quite expensive (circa 40 euro), however, I used a needle-nose pliers instead . It more or less worked, but the connections aren't as robust as they should be and I'm not entirely happy with the result.

What do you use to make these Molex connections? Did you invest in one of these specialised crimping tools?

I did buy a cheap crimp tool .. and got a cheap retrofit of a cheap chinese import crimper. Looks like they DIYed themselves some jaws that are almost but not quite right, and then failed to bolt them into the tool. The tool itself is OK but without the jaws its useless.

Still, you can get good results with needle nose pliers and practice. Takes time and they don't look as nice, but they do work. A lot of people solder them to reinforce the crimp, but be careful about stiffening the wire, solder infiltrated wire is prone to breaking when flexed.

This is a low cost (i.e. $40) general purpose Molex crimp tool. While not as easy to use as the higher grade crimp tools it gets the job done when used properly.

Molex part number 63811-1000...
http://www.molex.com/webdocs/datasheets/pdf/en-us/0638111000_APPLICATION_TOOLIN.pdf

The Molex datasheet above lists the variety of crimp part numbers (series) that it supports. Check to see if it will do the job for you.

From Digikey...
http://search.digikey.com/scripts/DkSearch/dksus.dll?x=0&y=0〈=en&site=us&KeyWords=wm9999-nd

I'm sure you can find this many other places. I just happened to have the DigiKey part number / link available so that you could see the price.

TC

Quote
Andrew Smith
Still, you can get good results with needle nose pliers and practice. Takes time and they don't look as nice, but they do work.

Good to know I'm not the only person who has resorted to this. My primary concern is that - even if I manage to make robust connections - it's probably a lot slower than with using a crimper (even with practice). Anyway, it's not an issue unless I decide to build another reprap.

Quote
TC
This is a low cost (i.e. $40) general purpose Molex crimp tool. While not as easy to use as the higher grade crimp tools it gets the job done when used properly.

Molex part number 63811-1000...
[www.molex.com]

Thanks TC. Will look into this.

I have a Sanguinololu board with the 0.1" pitch connectors and have soldered all the motor plugs and so on. I generally give a light squeeze with a pair of pliers so that the back end of the connector grips on to the insulation of the wire. I agree with the comment that it can stiffen the wire and make it more likely to break but I plan to tie in the cables so that any movement of the cable is not felt at the connector. Same is true of end-stop switches, where I have soldered on wires but will provide strain relief wherever the switches move.

Unless you plan to keep unplugging your cables it could be a problem but mine is set up and then zip tied in place permanently

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Experimenting in 3D in New Zealand

My feeling is that the molex is not needed, or even unwanted.
A better solution would be an RS232..
Still thinking about what would be an even better solution, as in cheaper.
Unplugging would be mandatory if one expects to fiddle around with cnc/engraving, as well as other options

dslc Wrote:
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> What do you use to make these Molex connections?
> Did you invest in one of these specialised
> crimping tools?

I dodged the issue by buying a set of ready-made cables with the same connectors in each end and spliced these into the motor cables. Each cable gives me two connectors and enough wire so I don't have to lengthen the leads (the Alltronics' motors had pretty short leads).

If I need to often plug and unplug something that needs more than an amp, I'll use Anderson PowerPole connectors. Those are pretty awesome.

Making your own molex connections is an expensive proposition. The crimpers are expensive (engineer pa-21), the ends are expensive and the terminals are expensive.

However, if you love things to be clean and neat then they can't be beat! Their little brother the pa-09 is extremely useful as well...

- akhlut

Edited 1 time(s). Last edit at 04/05/2012 04:41PM by akhlut.

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- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]

Have you watched nophead's video?
I wish I had seen this before I wired my Huxley. I ended up leaving some of the the wires too long and then soldered them as well with the result that the pins wouldn't go right to of the end of the socket.
I made the Mendel90 after watching this video and all the crimps went smoothly, much stronger than before and no need for soldering at all.

I have one of these, works well:

http://www.ebay.co.uk/itm/Crimping-Tool-Molex-0-1-and-0-156-Terminals-HT-225D-/170752067857?pt=UK_AudioElectronicsVideo_Video_TelevisionSetTopBoxes&hash=item27c19dc911

richgain Wrote:
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> Have you watched nophead's video?
> I wish I had seen this before I wired my Huxley. I
> ended up leaving some of the the wires too long
> and then soldered them as well with the result
> that the pins wouldn't go right to of the end of
> the socket.
> I made the Mendel90 after watching this video and
> all the crimps went smoothly, much stronger than
> before and no need for soldering at all.
I followed this video as well. Works perfectly, although you do need some small needle nose pliers and patiences.

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My Reprap blog

jds-reprap.blogspot.com

I use a universal crimp tool, which does about 100 different crimp types (I can't justify having a one trick pony that will only crimp one crimp pin type in my toolbox). You have to crimp the core then the insulator (so two separate presses), but unless you are doing a production run, this small time overhead is more than offset by the tools flexibility/adapatibility...

[www.precisionhandtools.co.uk]