Monday, August 21, 2017

Power/radio cables with over-moulding

I thought some folks might be interested to know how we are getting our cables fabricated, so here are some photos of the tool used for the low-pressure injection over-moulding that adds the red rubbery plastic over the connector and circuitry in the cable head.

First, here you can see a finished cable and the tool, which was designed and machined for us.  Unlike high-pressure injection moulding, where you can turn out multiple parts per minute, but the tool cost is tens of thousands of dollars, the complete tool design and manufacture cost here was only about AU$3,000 with our friends at Innovation Engineering.  The trade-off is that each part takes minutes to produce, instead of seconds. For now at least, that isn't a big problem.


Looking closer at the tool, you can see the big fat guide pins that hold it in proper alignment when assembled:

Then on the other half you can see this funny bar with the two brass pins.  This is removable, and held in with a couple of magnets.  It ensures that there are holes through the moulded body for the thumb-screws.  It needs to be removable, as you need to get the cable in and out of the tool.

Here is that same tool without it in place:

And here is the removable part itself. You can see here that it has the recess that fits snugly around the D-SUB25 connector, so that it doesn't get encased in plastic during moulding, but continues to stick out the end, as it needs to do, in order to be a useful cable:

Then finally, here it is all assembled (but without a cable inside):

As I have said before, it is so much easier to work with a company who is only a few minutes away, so that if there are problems, they can be quickly inspected and dealt with, and so that communications can be free flowing, so that everything goes well.

Now we are just waiting on the delivery of our next 45 of these cables, ready for our third trip to Vanuatu.

No comments:

Post a Comment