SAE ARP6673

The purpose of this ARP is to provide information on splices, and the definition of the preferred methods of splicing single core wires and multi-conductor cables supplied on reels by vendors, to facilitate their processing on automated wire processing systems to allow continued uninterrupted machine operation without requiring operator intervention. Suppliers of aerospace electrical wire typically supply wire and cable on reels. However, due to manufacturing limitations, it is extremely difficult to manufacture the required lengths ordered by the end user as a single piece without any faults. It is therefore the norm to supply wire and cable as multiple segment lengths on the reel to make up the required overall length for an order. Consequently, the wire or cable is either left with the unjoined ends of each segment protruding from the side of the reel, “ends out,” or with the wire segments spliced together. It is an aerospace industry requirement that splices in wiring shall never pass through the harness manufacturing process and into the aircraft or vehicle. To help ensure this does not happen, it is typical to use a knot and splice detector on wire processing equipment, such as the laser wire markers used in the initial stages of wire harness preparation. This will automatically detect any splices and stop the wire processing machine. On an attended machine, the operator can then check the fault and, if it is a splice, manually remove this and restart the machine. As more automated machines are introduced, there is a need for splices to be not only automatically detected but automatically managed and rejected by the machine. This will require the splices to be of a size and form that can easily pass through the machine without operator intervention. In this way, the machine can detect a splice, reject the wire in process, and restart production to remanufacture the faulty wire, and then continue in operation without the need for manual assistance. This feature is critical to automatic systems where there may not be an operator immediately on hand and particularly for “lights out” operation on an unattended overnight shift. Where wire is spliced, there are no standards applied and no guidance on how to join the wire ends. Wire manufacturers and distributors therefore use a range of in-house methods for splicing the wire they supply. This can often result in unacceptable, bulky splices that can be too large to pass freely through a typical wire processing machine. Such unacceptable splices are a distraction to manufacturing that cause unplanned downtime. Dependent on machine design, improper splices could cause wire jams that require maintenance intervention. As a result, wire waste multiplies, production comes to a halt, and costs increase. While an operator can manually remove the splice on an attended machine, this becomes an impediment to automated wire processing machines. It is therefore necessary to define the methods and the physical forms for splicing wires to facilitate the automated processing of splices on an automatic wire processing machine, such that it can continue operation without requiring operator intervention to resolve the problem of a splice once detected. This SAE Aerospace Recommended Practice (ARP) aims to set out acceptable means and forms of splices that will generally support the use of automated wire processing equipment. Discussion of splice techniques in this ARP are focused on their suitability for automated wire processing equipment and are not intended to represent all manufacturing or user needs for splices, splice design, or splice quality.