Robotic automation in apparel manufacturing is reviewed and investigated. Gripper design for separation and de-stacking of batch cut fabric components is identified as an important factor in implementing such automation and a study of existing gripper mechanisms is presented. New de-stacking gripper designs and processes are described together with experimental results. Single fabric component handling, alignment and registration techniques are investigated. Some of these techniques are integrated within a demonstrator robotic garment assembly cell automating the common edge binding process. Performance results are reported.

This Thesis addresses Factory Layout Problems, and reviews and evaluates the available layout techniques. Manufacturing as a system has been studied and reclassified for factory layout: space demands and spatial relationships have been considered as main principles of Factory Layout Planning. This forms a basis for the introduction of a new, more efficient Factory Layout Planning Methodology, denoted as SPACE MANAGEMENT. A new COMPUTER AIDED FACTORY LAYOUT PLANNING system is formulated as a tool for: - preparing 3-D templates of Work Station Modules and Equipment Modules; - drawing a requested interior of an industrial hall/bay in 3-D; - positioning any 'objects1 (spaces), via manual interactive programs i n 3-D; - automatic positioning of work stations and equipment in the bay, in 'technological' order (in 3-D), using an automatic positioning program, with a facility for: collision course finding(with objects within the bay), manual override for corrections, and finding an optimum size (width) of the bay. The resulting layout scene can be observed from any required Position and distance. The system includes a set of auxiliary programs for Manual Feeding of lines of work stations in 'technological' order and for basic capacity calculations. CAFLAP also opens a new way of economic evaluation of Projects and alternatives. CAFLAP is implemented in FORTRAN 77 and uses the Computer Graphics System PICASO.

No description available.

This is the thesis which explains the progress made in the analysis, simulation and testing of plastics forming. This progress can be applied to injection and compression mould design. Three activities of plastics forming have been investigated, namely filling analysis, cooling analysis and ejecting analysis. The filling section of plastics forming has been analysed and calculated by using MOLDFLOW and FILLCALC V. software. A comparing of high speed compression moulding and injection moulding has been made. The cooling section of plastics forming has been analysed by using MOLDFLOW software and a finite difference computer program. The latter program can be used as a sample program to calculate the feasibility of cooling different materials to required target temperatures under controlled cooling conditions. The application of thermal imaging has been also introduced to determine the actual process temperatures. Thermal imaging can be used as a powerful tool to analyse mould surface temperatures and to verify the mathematical model. A buckling problem for ejecting section has been modelled and calculated by PATRAN/ABAQUS finite element analysis software and tested. These calculations and analysis are applied to the special case but can be use as an example for general analysis and calculation in the ejection section of plastics forming.

Water models using perspex have been built to study the fluid flow and recirculation patterns developed in the sump of a steel continuous casting machine and the influences these have on the behaviour of inclusions. An experimental method has been devised to simulate the behaviour of inclusions in the sump and to study the apportionment of the input flux of inclusions between the molten mould powder layer and the strand. The method entails the uses of finely dispersed coloured paraffin oil in the inlet stream together with a floating colourless paraffin layer on the top of the water in the model mould to simulate the molten powder layer on top of the molten steel. A theoretical model has been formulated which relates the inclusion separation in the sump to the fluid flow there. The inclusion removal ratio in the sump for a given continuous casting machine can be predicted using this theoretical model. The model, using the properties of liquid steel and practicable casting speeds, demonstrates that the removal of inclusions of small size (< 40 um) from the mould sump is less than 5% efficient. Inclusion agglomeration plays an important role in inclusion removal. It has been shown that deep submersion of the SEN enhances the agglomeration of inclusion particle. Under certain conditions, for example, the average particle diameter in the meniscus region has been found to be as much as three times its value at the SEN nozzle. The use of fine alumina flakes or small air bubbles, together with a plane light source, has been found to be very successful in studying the fluid flow patterns developed in three-dimensional models. Employing this method, the fluid flow patterns developed on different planes within the model mould have been viewed and recorded photographically. The photographs so obtained have helped to explain the results obtained for the removal of inclusions. The fluid flow patterns developed when small outside diameter nozzles with deep SEN submerged depths are used have been found to be of benefit to the removal of inclusions. Increasing the SEN submerged depth promotes inclusion agglomeration and hence increases the inclusion removal ratio. Reducing the nozzle outside diameter and the casting speed increases the inclusion removal ratio in the sump. But the infleunces of these latter changes are not very strong, so that inclusion removal consideration need not influence the design strategies used for the casting speed and nozzle outside diameter. The SEN port angle has a little effect on the inclusion removal when using deep SEN submerged depth. Although argon stream introduced into the tundish nozzle stream can protect the nozzle blockage, it is not beneficial to the inclusion removal in the sump.

A room temperature water model of a tundish was design, constructed and operated. The model was equipped with a steam heating system that simulates that simulates the tundish plasma heating systems operated by some of the more modem continuous casting plants. Similarity between steam heating in the water model and plasma heating in the tundish has been established. A dimensionless criterion was developed to validate the simulation experiments and its represented by the plasma heating number. Using this similarity criterion plasma heating can be simulated by steam heating in an appropriately designed water model. A theoretical dispersion model has been formulated for the flow through the tundish and the parameters in this model determined from the results obtained from residence time distribution measurements. A conductivity method was used, a highly conducting species being injected at the inlet point and changes in conductivity monitored at the exit. Measurements were also made of the changes in temperature at the exit resulting both from changes in temperature of the inlet stream and from the use of steam heater system. A stable inverse heat conduction method has been developed in which the measured and estimated temperature are analysed in terms of a steady components of short duration. A finite difference method has been used to predict the effect on a thermocouple temperature of the deviatory components of the liquid steel temperature. The incorporation of these predictions into look-up tables has allowed an algorithm to be developed thet can deduce the current deviatory component of the steel temperature from the thermocouple response.

A detailed investigation is carried out for a novel process of die-less strip drawing, in which conventional reduction dies have been replaced by a die-less reduction unit having a rectangular hole of stepped configuration. The smallest hole dimensions are larger than those of the incoming strip, thus eliminating direct metal to metal contact and hence the problem of die-friction and consequential die wear. The strip is plastically deformed by means of the combined effect of the hydrodynamic pressure and drag force generated in the unit due to the motion of the strip through a polymer melt. An extensive experimental study has been undertaken, which showed that higher reductions were achieved at slower drawing speeds with gradual decrease in reduction at higher drawing speeds. The maximum reduction in area of the strip noted was, about 12%. Various parameters were changed to examine their effects on the performance of the process. Theoretical analyses have been developed considering Newtonian and non-Newtonian characteristics of the pressure medium. These analyses enable the predictions to be made of the pressure distribution , within the reduction unit, on-set of plastic yielding of the strip marerial, shear and axial stresses, and the percentage reduction in strip size. The analyses incorporate critical shear stress limit of the polymer melt, the strain hardening and the strain rate sensitivity of the strip material. The predicted results for the percentage reduction in strip size appear to under-estimate the experimental values at the slow drawing speed and over-estimate them at the higher drawing speed.

The present work has arisen from a continuing need to improve the performance of round-steel lifting (hoist) and mining chains, and the hypothesis that this might be done by modification of the link geometry. The finite element (FE) method has been used to analyse the stresses in the chain links. The effects of link length and the bend radius in the crown were considered. The effect of maintaining link length constant and departing from the conventional straight sided (standard) geometry by changing the link shape from eight shape (pinched), through straight sided, to elliptical has been examined. Mining chains made from non-circular section rod have also been investigated. The finite element work has been supported by practical investigations using through-yield strain gauges.

Post-implant annealing of InP and GaInAs is usually accomplished using thermal cycles of 10-30 minutes duration; this thesis reports the results of a systematic study of an alternative technique, 'rapid thermal annealing' (RTA), in which the implanted material is held at elevated temperatures for less than 180 seconds. Results were obtained using Hall-effect measurements, Rutherford backscattering (RBS), secondary ion mass spectrometry (SIMS), and photoluminescence (PL), amongst other methods. Iron-doped InP, implanted with magnesium, zinc or mercury was subjected to RTA and five different methods of protecting the InP surface were compared: the use of an indium-tin pseudobinary leads to tin incorporation and n-type surface layer formation above 700&deg;C; encapsulating layers of phosphosilicate glass, SiO2, Si3N4 or a novel 'dual' layer of Si3N4/AlK may lead to p-type, semi-insulating or n-type behaviour. This is shown to be due to the indiffusion of silicon from these encapsulants into the implanted substrate; this indiffusion is enhanced by implantation damage. RTA in a phosphine ambient gives the best surface protection at elevated temperatures, but leads to substantial outdiffusion and loss of the implanted dopant. Electrically active p-type layers were successfully obtained from both zinc and mercury implants. GaInAs was implanted with beryllium, magnesium, zinc and mercury and electrically active p-type layers obtained following magnesium implantation; electrical results were, however, dominated by the quality of the starting material and not reproducible. 'Proximity' annealing under a GaAsP or GaAs cover piece gave adequate surface protection for GaInAs at annealing temperatures up to 800&deg;C. The presence of an amorphous layer In InP and GalnAs is shown to be detrimental and the maximum amorphous thickness which can be fully regrown is found to be about 250 nm at 750 &deg;C. It is suggested that solid phase epitaxy of thicker amorphous layers is inhibited by the local nucleation of microcrystallites within the remaining amorphous material and a model describing the regrowth of III-V compounds is presented. Substantial redistribution of the implanted dopant occurs during RTA of InP and GalnAs, the shape of dopant profiles is modified by both the residual damage present within the material and the form of surface protection employed. Several models of acceptor diffusion in iron-doped InP are compared and discussed.

In recent years demand from production industry for high performance cutting tools, aero and automobile engine parts has prompted research into both existing and novel methods of laying down hard, low friction coatings . A key process for the production of such coatings has been Physical Vapour Deposition (PVD) which has proved to be a consistent and reliable tool for industry. For this technique to continue to be improved and more advanced coatings to be produced, research at the fundamental level is required. This thesis describes research investigating the behaviour of the steered arc cathode spot and methods of improving existing steered arc coating technology. The majority of existing steered arc systems use either permanent magnets or a combination of permanent and electromagnets to steer the arc. Described here is a novel system which employs a pair of electromagnetic coils of cylindrical geometry which enable the arc to be positioned on a circular orbit through a range of continuously variable radii. In addition to this the coils are capable of controlling the transverse and normal magnetic field profiles independently of the steering radius selected. This enables the behaviour of the arc spot to be investigated under a range of magnetic field conditions thus allowing the comparison of measured arc behaviour with a new model of arc motion. Care has described the motion of the arc spot as a biased random walk and has derived an analytical solution to describe the time dependent, probability density function for the arc position in two dimensions. Two distributions are proposed (one in each dimension); the first describes the probability density for the arc position in the direction of driven motion, the second the probability density in the direction of arc confinement. The shape of these distributions is dependent upon the transverse and normal components of the applied magnetic field. A series of experiments are described here that measure the shape of these distributions as a function of either magnetic field, cathode material or both. In the case of the distribution of the arc position in the direction of confinement the width of the distribution is measured as a function of normal and transverse field components. In the direction of steered motion, distributions of arc orbital transit times are measured for a number of cathode materials: analysis of these distributions allow the determination of a mean macroscopic spot velocity and the spot diffusion coefficient. In both cases comparison with Care's model reveals good agreement between experiment and theory to the limits of the experimental apparatus. A further experiment was also conducted to test the prediction that the diffusion coefficient (measured in the direction of steered motion) is independent of the applied field. In this case results are inconclusive and further work is recommended. The mean spot velocity and diffusion coefficients for four materials were measured; titanium, zirconium, aluminium and 316 stainless steel. The results for aluminium and stainless steel compared favourably with some measurements performed by other workers, whilst those for titanium and zirconium are new results with no data available for comparison.