Cable Machine Research Articles

A two-stage traveling salesman procedure for the single machine sequence-dependent scheduling problem

A scheduling method for a single machine scheduling problem with sequence dependent setup times is presented where similar products produced on the machine can be partitioned into families. A two-stage traveling salesman heuristic procedure is developed. In the first stage an n × n symmetric setup time matrix is generated for n products and the products are classified into families (groups) using either a hierarchical cluster analysis procedure or the users internal groupings. A Traveling Salesman Problem (TSP) is then solved to obtain an efficient sequence for each family. In the second stage, a special purpose traveling salesman heuristic is developed to combine the already sequenced families in an efficient way. The results of the computational study show that the Two-Stage Traveling Salesman procedure is approximately two to four times faster than the well known TSP heuristic by Lin and Kernighan, while the solution quality is comparable to Lin and Kernighan's heuristic. The paper also illustrates an industrial application of the procedure for an automated cable assembly machine.

An Automated Cable Assembly Machine

A hand-built cable purchased from an outside vendor, and used in large quantities at the Denver Works to assemble AT&T private branch exchange (PBX) systems, did not meet quality, shipping, and cost expectations. Therefore, Denver engineers began in-house automated production of this cable, using robotics and custom-designed automation. This paper describes the configuration and operation of an automated cable assembly machine composed of six major workstations that, when operating simultaneously and sequentially, completes one cable assembly every 30 seconds. Restocking the machine with piece parts is the only manual intervention required.

Resolutions to difficulties experienced in SSC cable fabrication during the initial scale-up period

A prototype high-speed cable machine for the Superconducting Super Collider (SSC) has produced the majority of the cable needed for the SSC Dipole Program. However, several cabling difficulties were experienced that were not seen previously. These difficulties were due to new techniques and equipment relating to the high-speed production of cable meeting SSC specifications. These difficulties included mandrel alignment, Turk's-head roller alignment, and Turk's-head drive equipment. The solution to these problems is discussed. By modifying the Turk's head, it is possible to manufacture SSC cable to the current specifications without defects.

A Study of the Behavior of a Uniaxially Oriented Polyethymene Tape/Oil Insulating System Subjected to Electrical and Thermal Stresses

The occurrence of discharges in an insulation system consisting of lapped uniaxially oriented polyethylene tapes impregnated with dodecylbenzene oil and the behavior of air bubbles injected into the structure have been investigated. This insulation system should be suitable for use in power transmission cables because the tape is generally compatible with the oil and has suitable mechanical properties for cable manufacture in a conventional cable taping machine. The behavior of bubbles in the systems was monitored with a transparent electrode and a video system. An electronic protection system was used to remove the applied voltage just before breakdown so that the damage done by discharges to the tape structure could be measured. The discharge inception voltage was found to decrease with increasing butt gap depth and with increasing temperature. Bubbles were found to divide repeatedly and eventually to disperse at stresses above discharge inception. The rate of dispersal increased with increasing applied stress and temperature. Examination of the damage done to tapes showed a high level of correlation between the total energy of discharges in the insulation structure and the total surface area of visible damage. Measurement of the total discharge energy appears to be a promising diagnostic tool.

Optical Fiber Cable Installation Techniques

When installing junction optical fiber cable, which essentially must be longer than conventional metallic-conductor cable to effectively reduce splice loss, the applied tensile load must be within tolerable limits to prevent an increase in loss and a decrease in lifetime. It has recently become possible to meet this requirement through the development of a new cable installation system which makes use of a modified cable pulling truck and a new intermediate cable pulling machine. Furthermore, this new installation system, capable of achieving a 1.0-1.5 km installation length for all types of cable accommodations, has already been put into practice. In addition, this paper presents three new cable installation techniques for facilitating subscriber optical fiber cable installations under various environmental conditions: a tension-controlled pulling technique, a cable pulling eye attachment technique, and a cost-effective damage-free cable installation technique in older buildings.

Performance of field-installed 13-μm band single-mode optical cable

This paper describes the performances of 1.3-μm-band single-mode optical cables, of a single-mode fiber splicing apparatus, and of a cable installation machine. It also discusses optical loss characteristics in a 20-km long repeater section of a 400-Mbit/sec optical transmission system. An average cable loss of 0.48 dB/km and an average splice loss of 0.11 dB were achieved at 1.3 μm in the field. Optical loss distribution in the 20-km long repeater section was investigated experimentally. Optical losses between 10.2 and 13.9 dB were attained for the 20-km section at 1.3 μm.

The Reduction of Capstan Effectiveness by Cable Bending Resistance

The simple exponential capstan equation relating output tension to back tension is valid for most cable applications. However, when the capstan is small and the back tension is low, the bending resistance of the cable reduces its conformity to the capstan, and thereby reduces the effectiveness of the capstan. The conditions under which a cable will not conform to a capstan are worked out. These conditions can be expressed as a minimum back tension required for the capstan to work. Two applications are considered. For a typical coaxial cable on the ship cable machine at a back tension of 5000N (1124 lbf), the effect of bending resistance is negligible. For a different cable on a captain-pair at a back tension of 100N (22.5 lbf), the effect is important. The equations used here are also applicable to other cases where a cable is pulled and bent.

Portable Cable Winch for Hillside Forests

ABSTRACT SMALL lightweight equipment, usable and trans-portable by handcrews on steep slopes, was identified by field managers as necessary to increase the efficiency of handling forest residues generated by logging opera-tions. Three small cable winch machines have been developed and the preproduction models were evaluated in the field by the Forest Service. A single-drum, direct gear-drive design was tested extensively and met all the design objectives except cost.