Quote:
Originally Posted by Guru
We know that PWM cables break easily, but why? What makes them so fragile? And is there a way to just buy new heads instead of entire cables if a cable 'breaks'? We've been through 3 'broken' PWM cables, 2 of which were working properly.
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This is what I bought to do custom cable construction and appear to be identical to the connectors IFI uses on their cables.
FCI Bergcon series connector:
65039-034, 3 pin housing
47715-000LF, female pin (there are quite a variety available, this one is for 22-26AWG, tin-lead contact, high force. Gold contacts also available.
48116-000, male pin, 22-26AWG.
Mouser has stock and good pricing.
Note that the IFI supplied ables appear to use gold plated contacts, and while I'd normally recommend that, the tin pins can work well enough for the short life that the robot will see that you can shave a few bucks on your budget by going with the cheap pins.
While the $1000 crimp tool would work well, you may find another crimp tool that will also work. I have an old Waldom tool that is designed to fold over the crimp pins in a double "U" shape that works well on the contact crimp, but not so well on the strain relief crimp. Its a bit tedious but I do trust the resulting connection.
Out of the four IFI supplied cables I tried to use this year, I have found two cables that were bad. I didn't bother to see which wire or end was bad. One was a hard fail, the other intermittent.
The likely problem is with a poor crimp rather than a broken wire, but I have yet to put them under a microscope to QA them. This sometimes occurs if the wire isn't properly stripped and the crimp gets a bit of insulation rather than copper.
The pins release from the housing quite easily by gently lifting the little plastic side latch and then pulling the wire out. If it doesn't slide out easily, the latch isn't up far enough. Use the tip of an X-Acto knife or jewler's screwdriver.
Repair may be possible with a small (i.e. 15W) soldering iron and a tiny bit of solder to bond the copper to the contact. I recommend a Metcal iron with a small tip and some 0.015" dia. solder, and using a microscope to inspect your work. My point here is that this is deft work and it takes a light touch... a little solder will go a very, very long way... don't over do it.