Cable splice moulding - Page 1
Forum section: electronics / projects

author: sigteq
author_rank: Newbie
timestamp: August 28, 2017, 04:28:34 pm
content: HiAnybody have experience of joining 2 cables into one using a moulding at the joint as in the attached photo. Im trying to source a kit or jig to run off 100 cables of various lengths with a neat finish, shrink wrap won't do, unless there's a 2 into 1 product, 4.5mm diameter cable in and two by 3.5mm out.Any help would be much appreciated.RegardsLarry

author: ajb
author_rank: Super Contributor
timestamp: August 28, 2017, 04:56:05 pm
content: There are heatshrink splitters, but maybe not at the size you need, and they're not cheap. This one hits your split side but not you large side requirements:https://www.mcmaster.com/#73575k61Henkel's Technomelt system might be what you want. I think a rep once told me it would cost around $10k to get started, including the first mold set, but don't quote me on that. Susbequent runs should be less expensive once you already have the equipment.If that kind of investment isn't worthwhile for you, then I would talk to a company likeSmooth-On. I'm not sure if they distribute in the EU, but they have a wide range of casting and molding products and would certainly be able to point you in the right direction. 100 pieces is enough that you probably don't want to be mixing individual batches of casting plastic, but if you could setup a gang mold to do 5-10 at a time that wouldn't be so bad.

author: tooki
author_rank: Super Contributor
timestamp: August 29, 2017, 03:01:09 am
content: Take a look at these:http://www.ebay.com/itm/HiFi-Carbon-Fiber-Pants-Boot-Y-Splitter-1-To-2-Speaker-RCA-Cable-Audio-3Colors-/282156747359?var=&hash=item41b1da4a5f:m:mw_DEarO_JbOCLwujFxttuA

author: jbb
author_rank: Super Contributor
timestamp: August 29, 2017, 08:40:12 am
content: Oh no... you're entering the world of custom cables. Abandon all hope all ye who enter here... the damn things are addictiveIf you need it fast, find some glue-filled heat shrink with a high shrink ratio (3:1, 4:1 or more). The results will be sufficiently ugly that people won't keep asking you for moreIf you want it nice, this looks like a job for an overmould (or overmold). There may well be someone within reasonable distance who can do it for you. You could try looking for contract electronics manufacturers within your country.Over moulding is, as the name implies, moulding a polymer over something. It's like a cheap version of plastic injection moulding. (Lower pressures required mean the machines are much much cheaper.)To do an overmould, you'll need a tool designed and made. This could quite possibly be a two-piece aluminium tool, and not super expensive (compared to tool steel for plastic injection moulding with moving sliders and ejector pins). I expect that you should be looking at less than EUR2000 to get started (but I've never priced one in Europe).If you can't design and manufacture the tool, the people who run the machine may be able to help with that.

author: dmills
author_rank: Super Contributor
timestamp: August 29, 2017, 08:59:03 am
content: Back when I was in the sonar transducer game, we used to do this in house quite routinely.Mould tools were often plastic (yes, the pressures involved are that negligible), with a PU fill and (low) vacuum degas.The trick however is in surface prep to get the PU to properly wet the cables, depending on the cable jacket, here be magic.There are a mix of mechanical abrasive and chemical surface treatments that are sometimes something of a case of experimentation to get right, but it is not actually that difficult. Expect to be using MEK and other such solvents together with some nastier things if trying to do this for PTFE wires (Pain in the arse).One nice trap is that water can get down between the outer sheaf and the individual insulated cores if the jacket gets damaged, to stop this at the moulding you must make sure that both the outer and the individual cores wet out fully, testing this at 2km pressure depth sometimes got exciting when things failed.Regards, Dan.

author: sigteq
author_rank: Newbie
timestamp: August 29, 2017, 01:37:04 pm
content: OKSome extremely useful responses, thanks all, the carbon fibre "pants" might do what I need for now, but as it's beginning to become a bit of an obsession, im going to run-up a 3d print of an "overmould" to see how that turns out, I'll use SolidWorks to create an stl, if its a success, the next step may be to invert the design and have an attempt at a mould, I see simple hand operated plastic injection moulding tools on-line for 300 - 400 Euro.may be back with an update.Regards