EuroWire November 2016

Technical article

Manufacturing of compact conductors, highlighting the benefits and potential cost reductions in the whole stranding process By Sean Harrington, Ceeco Bartell Machine Systems LLC

Introduction Ultimately, every cable manufacturer aims to make a quality product using the least amount of resources in the fastest time. To do this, they must understand the critical parameters that affect the strand they wish to make. Once this is accomplished, finding the hardware to provide them with the most flexible and effective process is relatively easy. The aim of this paper is to present a technological solution in the process of the manufacture of compact conductors, which brings cost savings from the wire drawing process through the cabling and into the extrusion process. This is the use of the roll form technology, which allows the use of a single input diameter wire to be utilised throughout the stranding process, giving significant process savings and advantages. stranded conductor requires its own drawn wire diameter. Each wire diameter typically requires a new string up in the wire drawing machine. Some conductor designs require more than one drawn wire size. Similarly, multiple set-ups in the stranding process are necessary for each size of conductor. The set-up time taken on both the drawing and stranding machines, combined with inventory levels that are Traditionally, a finished

requirements of those designs are determined that the choice of the optimum manufacturing cell can be considered. It should be noted that the concept of using a single input wire to manufacture a range of finished conductor sizes is not new; it is used within the confines of most manufacturing plants within the allowances of the current specifications. It has been used extensively in Europe where strand programmes using the single input wire diameter to cover a range of finished conductor sizes has been in existence for decades. The potential cost reductions using this process can be split into the following areas: Process Savings The obvious impact of the incorporation of roll forming into the stranding process is shown in Figure 1 . While still working within the constraints of the IEC and ASTM standards, the roll forming process allows the number of wires required to produce a range of conductors to be reduced dramatically. In this case, to cover 35mm 2 to 240mm 2 the number of wires has been reduced from eight to two. • Process savings • Material savings

necessary to manage the number of wire diameters, represent unnecessary activities that add to the conversion cost from rod to strand. The SIW mentality effectively eliminates much of this unnecessary activity associated with the traditional set-up by using the same drawn wire diameter to finish a range of stranded conductors. The result is: • Increased wire drawing output • Reduced wire drawing die inventory • Reduced scrap • Significantly lower work in process • Minimum strander payoff changes • Increased strander output • Shorter lead times • Enhanced JIT manufacturing mentality • Streamlined overall stranding process Probably more to the point is a significant reduction in the variables that the manufacturer needs to manipulate in the manufacture of any strand programme. The change in philosophy that is required to effectively use single drawn wire diameter to produce the required range of finished strand conductors is to replace the flexibility of stranding the same number of wires using different diameters with stranding different numbers of wires using the same wire diameter. In general, the benefits of the SIW mentality are independent of the strand manufacturing process used. It is only when the specific strand designs have been defined and the production

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November 2016