Wire Fencing (Part 1): Determinants of Wire Quality
Knotted wire fences are fabricated on specialised machines. The input material is typically galvanised steel wire. However, the quality of the input wire used by the Fence Producer is beyond control of the Machine Manufacturer. The problem is that wire strand breakages have been reported during fabrication and subsequent field erection. This is an issue for the Fence Producer because of the lost productivity, and the potential for reputation (brand) damage for both the Manufacturer and Producer. While existing standards do exist for wire, even wire that meets these standards is known to fail during fence fabrication. Thus there is a need to better understand how the quality of wire affects the manufacturabil- ity of fences, and to identify, or if necessary create, a test for wire quality that is able to be conducted by Fence Producers. In this research, samples were obtained from known good and failed fences and wire coils, and subjected to a variety of physical and metallurgical tests. These were then statistically examined and compared to the known fate of the fence, to determine the sensitivity of the test. Four potential tests were evaluated: Tensile strength (UTS), ductility, 3-point bend- ing, microstructural, impact energy, plus a fifth novel new test called linear torsional ductility (LTD). From these tests, it was evident that the linear torsional ductility test was the most sensitive and reliable indicator for wire quality. This paper is part of a collection, with companion papers examining material properties of wire, microstructure, impact energy for wire, knot performance, and the testing of whole fences.
Study on parameters influencing the corrosion of metallic coatings on wire exposed to marine environments
This study focuses on the influence of specific parameters on wire corrosion with special emphasis on zinc and Zn-5%Al coatings. The mode of capture of marine aerosols and the influence of wire surface roughness are discussed for large and small marine aerosol particle sizes. It is also shown that the integrity of ternary alloy coating is a critical factor influencing long-term performance of Zn-5% Al coated wire in atmospheric marine environments.
High speed servo control of multi-axis machine tools
Abstract Advances in high-speed machining technology, including those in spindle speeds and cutters, are out-pacing advances in the servo control performance of machine tools. To close this gap, new machine tools and improved controls must be developed. Improvements to machine tools under development include special-purpose machine tools, the use of advanced materials, the replacement of ball screws and ways with linear motors and roller guides, and the use of parallel link actuators. This paper focuses on the control issues that will become increasingly important as these high-speed machining and high-speed machine tool advances are realized. The main issues in high-speed servo control are feed rate planning, and servo loop control laws. A method is developed in this paper which takes advantage of the full performance envelope of each axis in an arbitrary path. This near-complete usage of the servo capabilities of a machine tool results in reduced cycle time or reduced path error. A servo loop control law is then developed that uses the axis performance envelope as well as instantaneous position, velocity, and acceleration information of the target path and machine axis to improve servo performance in the presence of disturbances.