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Three test platforms for long-term continuous loading are adopted to test the actuator prototypes of the 500-meter aperture spherical radio telescope (FAST). However, the wire ropes that are the key components of these platforms often break during testing. The purpose of this paper is to present an effective dimension design method for these wire ropes. This method is based on fatigue reliability theory.

Three types of stresses are introduced into the total stress model of the wire rope according to the complicated stress conditions. The fatigue strength of the ropes is also discussed in this paper. Then, the total stress model and the results of fatigue strength analysis are applied to set the optimization function for these wire ropes. Subsequently, this optimization function is used to calculate the reliability of previously developed wire ropes in relation to the actuator test platform.

The wire rope is unreliable, which is a finding that corresponds to those of previous tests. Upon drawing the optimal curve from the optimization function (whose optimal objective is the wire diameter), a wire rope is optimized for the FAST actuator test platforms. Finally, this optimized rope is used on the new actuator test platform. No fracture phenomenon has been detected in tests conducted over the past six months.

The fatigue reliability theory-based optimization function for wire ropes can be adopted for the universal dimension design of other wire ropes.

A study was undertaken to evaluate the thermosonic gold‐wire bonding capability to Ti‐Pd‐Cu‐Ni‐Au thin film metallisation on newly developed polymer hybrid integrated circuits (POLYHICs). (The POLYHIC technology incorporates alternating layers of polymer and metal added to conventional Hybrid Integrated Circuits which provide for increased interconnection density.) Destructive wire‐pull strengths were measured as a function of varying wire‐bonding machine operating parameters of wedge bond force, wedge bond time, temperature, and ultrasonic energy. All data were evaluated and compared with wire bonding under similar conditions to thin film circuits on Al2O3 ceramic. The results for wedge‐bond associated failures indicated that machine operating parameters of wedge bond force, time and ultrasonic energy similarly affected the average wire‐pull strength for both the ceramic and POLYHIC circuits. Pull strengths for equivalent metallisation schemes and bonding parameters were generally slightly higher and more tightly distributed for bonds made to metal films on ceramic. A strong correlation was found to exist between wire‐pull strengths and surface topography (as measured by a profilometer technique) of the thin film metallisation for the POLYHICs which had both smooth and rough metallisation surfaces for metal films on top of the polymer. The results indicated that rough metallisation bonded more easily and yielded much higher wire‐pull strengths. Also, rougher films were shown to effectively increase the parameter‐operating windows for producing reliable wire bonds. A semi‐quantitative analysis was developed to help explain this correlation. Surface topography effects were also found to be a key factor when evaluating wire bondability as a function of substrate bonding temperature. Wedge‐bond strength was essentially independent of temperature for bonds made to rougher metallisation while a strong temperature dependency was found when wire bonds were made to smoother films.

The influence of process heat, with regard to wire‐ and substrate‐materials, on the adhesion of wire‐bonds was investigated. Temperature increases up to 200°C were measured on the interface between surface and wire. This temperature is the basis for demonstrating the important influence of dissipated process heat on the cold welding process of wire‐bonding. Complementary calculations to evaluate the equation of thermal conductivity were carried out using the finite element (FE) method. Bonding tests were able to verify the calculations. These thermodynamical considerations give us a new method to optimize the construction and the choice of materials within the wire‐bond process.

At present, over 95 percent of the manufactured packages are still being wire bonded. Owing to the ongoing trend of miniaturization, material changes, and cost reduction, wire bond‐related failures are becoming increasingly important. This paper aims to understand these kinds of failures.

Different finite element (FE) techniques are explored to their ability to describe the thermo‐mechanical behavior of the wire embedded in the electronic package. The developed nonlinear and parametric FE models are able to predict the strong nonlinear behavior of wire failures and multi‐failure mode interaction accurately and efficiently.

It is found that both processing and testing environments as well as the occurrence of delamination strongly increase the risk for wire failures. The results indicate that processing and testing influences are much less than those of the delamination.

Package designers should focus on limiting the occurrence of delamination around wire bond and/or stitch areas.

Combining the strengths of predictive modeling with simulation‐based optimization methods, the optimal wire shape is obtained.

GaAs electronic devices are becoming increasingly used in the microelectronics industry especially in solid state microwave, ultra high speed digital processing and optoelectronic applications. However, in the manufacture of the GaAs devices, problems due to the inherent brittleness of the GaAs and batch to batch variability of the bond pad metallisation have commonly been experienced. This has resulted in some difficulties in wire bonding to GaAs devices with ultrasonic and thermocompression wire bonding techniques. This paper describes a programme undertaken to investigate Au wire bonding techniques to GaAs devices. Specifically, bonding trials have been performed on a range of GaAs substrates using pulse tip and continuously heated thermocompression bonding and ultrasonic bonding. The results of this work have shown that thermocompression and ultrasonic wire bonding techniques are cabable of producing acceptable bonds to GaAs devices, although some of the advantages and limitations of each technique have been demonstrated. Thermocompression bonding with a continuously heated capillary gave the most tolerant envelope of bonding conditions and highest bond strengths. Pulse tip thermocompression bonding gave a less tolerant envelope of acceptable bonding conditions, required a longer bonding time and the wire was weakened above the ball bond. Ultrasonic bonding did not require any substrate heating to give acceptable bonds. However, the choice of equipment can be critical if damage to the device is to be avoided.

Discusses the distress of mine rope‐wires, under the diverse states of stresses and strains of physical, chemical and mechanical origin. Mine rope‐wires undergo complicated cycles of stresses and strains inside the depth of coal and metal mines. This assumes special significance during summer inside the deeper mines. Summarizes recent studies in this field and compares their results.

Wire harness fabrication is extremely labour intensive. Previous attempts to automate the process have used X‐Y tables and have only been partially successful due to limited degrees of freedom. Unimation has demonstrated the feasibility of using a robot to integrate the wire termination, insertion, routing and testing operations into a single manufacturing system.

The purpose of this paper is to present an assessment of the ability of combined finite and slab element method (FSEM) for analyzing the wire flat rolling process.

Using the FSEM, the effective strain field of flat rolled wire is predicted for different reductions in height and frictional conditions. The validity of the method is assessed by performing the Vickers microhardness measurements on the flattened wire cross section. Also, the creation of macroscopic shear bands in cross section of the flat rolled wire is investigated and confirmed by microhardness and metallographic examinations. Moreover, the lateral spread and width of contact area are predicted by the FSEM for different reductions in height and frictional conditions.

The FSEM and microhardness results show the minimum and the maximum effective strains at the round edge and center of the flattened wire, respectively. Also, the results show the bands of maximum effective strain at cross section of the flattened wire, i.e. macroscopic shear bands.

This paper can be useful in rolling industries to produce electronic parts, various springs, trolley cables, piston rings, and guide rails.

The paper shows the applicability of the FSEM for calculating the effective strain field and geometry of wire after wire flat rolling process.

The PROCESS OF MAKING WIRE by drawing operations through dies, as distinct from hammering, though believed to be several thousand years old, until the last century was performed only by man‐, horse‐ or water‐power, so that production was slow and small. These old methods could not meet the greatly increased demand that then arose for wire of all kinds, such as copper wire for electrical purposes, and consequently power‐driven multi‐die benches were developed. Drawing speeds were still limited to several hundreds of feet per minute because of the rapid wear of the chilled iron and steel dies then used; but with the introduction of tungsten carbide dies and diamond dies, speeds were again increased, and now figures of 2,000 ft. per minute for steel wire, and 5,000 ft. per minute or more for copper and aluminium, are commonplace. These advances have required improved drawing lubricants, and future increases in drawing speeds likewise largely depend on improving lubricants still further. The general problem is to provide adequate lubrication for long die life, coupled with the intensive cooling that higher drawing speeds compel.

This paper aims to analyze the effect of Au wire size and location of hook during wire pulling test to identify the variation of results obtained.

Two hook locations, namely, location A and location B were used to analyze the effect of hook location. Location A was the same as the hook location required by MIL-STD-883E standard, whereas location B was located near to the second bond. The correlation between new purposed failure modes and MIL-STD-883E standard was developed to reflect on the pull strength with the physical failure.

It was observed that fine pitch Au wire has higher variation and lower process capability of pull strength. Au wire pulled by the hook at location B provides a more representative result compared to that at location A. Fifty per cent or more of Au remnant is required to be considered as a good and reliable Au wedge bond based on the new purposed failure modes.

The evaluation of gold (Au) wedge bond requires a new proper wire pulling test method. This is due to the large variation obtained from the application of current practice of wire pulling test.