QFD and CE as Methodologies for a Quality Assurance in Product Development

Quality Function Deployment — QFD combined with Concurrent Engineering — CE as a support tool for the competitive strategy on product development is devised. In this study, beyond the proposed method, it is intended to develop relations with innovational models, arrangements of innovation and technology transfer, learning in organizations, and how the diffusion of knowledge occurs. QFD can also be one those main tools of CE as this identifies the customer’s main requirements translating into the features required for products. The field survey of exploratory and descriptive type, using the questionnaire as data collection technique, was carried out in the manufacturing companies in the fast growing sectors of automobile industries in the State of Parana located in the Southern of Brazil. The selection of sample companies was made intentionally to guarantee of return of answer through the accessibility criteria. The reasons for this fact that can be pointed out are: the use of “home made” methodology to fulfill customer’s requirements, unknowing of the methodology, and the lack of adequate training to use QFD. It is expected that the results of findings, if disseminated adequately among local companies, will help to enhance the competitiveness performance beyond the local market scenario.

Methodological Proposal to Evaluate Industrial Logistics Through Formalization

In the global world reality the success of large companies depends on a permanent logistics evaluation. But to measure the stage of logistics level, a methodology, models and references are required. The national and international performance measurement in logistics activities references was used. This was carried out in order to develop a field survey, using a methodology, model and references described in this paper. Also, survey results on the use of formalization in logistics are analyzed, i.e. how the logistics organization influences the whole structure to improve the supply chain management.

Study of Liquid Injection on Pressure Drop of Refrigerant Mixtures Inside Enhanced Surface Tubing

Two phase flow pressure drop characteristics observed under liquid injection during boiling of refrigerant mixtures R-404A, R407C and R507 as well as R-410A are presented in this paper. Experiments showed that liquid injection tends to decrease the pressure drop during boiling which will have positive impact in increasing the boiling heat transfer rate, heat flux and system efficiency. However, condensation data demonstrated that liquid injection increases the pressure drop. In addition, the data also reveals that the refrigerant under investigation exhibit the same behaviour at higher Reynolds numbers or mass flow rates.

Numerical Study of the Pusher-Type Billet Reheating Furnace

In the present work, a commercial CFD software package, FLUENT, was used to develop a three-dimensional model of pusher-type billet reheating furnace for the second high speed wire rod plant of XiangTan Iron and steel Co. Ltd. The purpose of the study was to gain a better understanding of the gas flow and velocity and pressure distribution in the furnace. The results show that the numerical results are in agreement with the practice and the characteristics of the furnace configuration. The CFD model can be used to improve the performance and structure by analyzing and studying the behavior of the reheating furnace.

Modelling Processing of Unfilled and Long-Glass Fibre Reinforced Thermoplastics in a Screw-Barrel Unit

In injection moulding, long glass fibre reinforced thermoplastics (LGFT) are an attractive way to produce large parts at low cost. The strength of the part depends chiefly on the average fibre length, fibres which are subjected to considerable attrition during processing in conventional three stage screws. First of all, in this study we have coupled a melting analysis in a conventional screw to a model of fibre breakage whereby a fibre anchored at one end in the solid bed is submitted, at its other end, to the intense shear stress of the molten polymer flowing in the film close to the barrel. As the melting of the solid bed progresses, more fibres are unlayered and submitted to bending which intensity is depending on both the fibre length and orientation. When the bending is too high, the fibre breaks. Bimodal fibre length distribution are obtained and compared to existing data. The sensibility of the model to main processing parameters such as screw rotation, initial fibre length, viscosity, barrel temperature and screw geometry are also investigated. Next, we present a new analytical solution for flow of a viscous fluid in a single screw channel that takes into account the torsion and curvature of the channel. Contrary to common knowledge in polymer processing based on the Parallel Plate Model, we found that, in the case of cross-sections with large aspect ratio, torsion effects can be significant. The implication of the model on velocity field, residence time and mixing efficiency is investigated and compared to the predictions of the classical Parallel Plate Model, to finite elements calculations, and to 3D experimental measurements. Indeed, an innovating device has been developed in our laboratory to visualize the flow of a viscous fluid in the channel of a screw. It consists of a transparent barrel and of a rotating screw, pumping a transparent viscous fluid at room temperature. A particle plunged in the flow is constantly monitored by four video-cameras placed around the barrel and recording its position in a frame. The 3D path lines are then computed.

Model Reference Adaptive Control of SUT Building Energy Management System

Model Reference Adaptive Controller (MRAC) design, for Sharif University of Technology (SUT) Building Energy Management System (BEMS) is addressed in this paper. A reference model with fuzzy adaptive control rules was employed to design the controller for a system with time delay and model parameter uncertainties. Simulation study shows good performance of the closed loop system with optimum energy consumption for this system under external load disturbance.

Relationship Between Vibrations and Mechanical Seal Failures in Centrifugal Pumps

A reduction of radial vibrations in mechanical seals increases the life of the seals in centrifugal pumps. Mechanical seals consist of two smooth seal faces. One face is stationary with respect to the pump. The other rotates. Between the faces a fluid film evaporates as the fluid moves radially. Ideally, the film evaporates as it reaches the outer surface of the seal faces, thereby preventing leakage from the pump and effectively lubricating the two surfaces. Relative vibrations between the two surfaces affect the fluid film, damage the faces, and decrease the life of the seals. In a series of industrial applications, different techniques were used to minimize vibration, and the life of the seals was shown to significantly increase. The operating speed was controlled in one case, the bearing design was replaced in another case, and the stiffness of the pump was altered in still another case. The common corrective action in each case was a reduction in vibration.

A Model for Contaminant Transport, Aggregation and Deposition in Lubricated Contact of Rough Surfaces

Effective prediction of lubricated contact poses an especially challenging problem. On the one hand surfaces are non-smooth at micron-scale while, on the other hand, a lubricant contains varying degrees of impurities in form of particle contaminants. An accurate model for lubricated contact, therefore, must be able to account for the various interactions that include particle-fluid, particle-particle, fluid-rough surface, particle-rough surface and rough surface-rough surface interactions. In the current study we propose the use of Lattice Boltzmann Method (LBM) and JKR theory for elasto-adhesive contact to simulate the particle transport processes in a lubricant flow between two rough surfaces. A particle dynamics simulation method is proposed to predict the interaction of a group of particles. The particle-particle and particle-boundary interactions are modeled by an extension of the JKR theory in which viscoelastic interactions are included through the implementation of the Kelvin-Voigt stress-strain relations. The particle-fluid interaction is calculated from the LBM simulation. Time scale relations between LBM and particle dynamics are characterized. Simulation results show the effects of particle density and surface roughness on frequencies of particle-particle and particle-boundary impacts, particle deposition rate, particle cluster forming and fluid boundary pressure changes due to particle deposition. A parametric study is performed to elucidate the effect of rough surface geometry and the relative velocity of the surfaces on friction and lift. The results provide fundamental insight on the contamination effects on wear and life of lubricated surfaces.

Cost Estimation and Quality Comparison for Sound Welds

A number of new materials are being developed for advanced applications like nuclear pressure vessels, missile casing and pressurized chambers for space launching vehicles. These newly developed high strength alloys demanding high strength joining, put rigorous requirements on the manufacturers to weld smartly i.e. sound welds at competitive cost. Welding is a very complex phenomenon and the quality and cost of the weldment is a function of interaction between a number of variables, making it more difficult but still indispensable to estimate the cost effects of different welding processes for smart welds. The primary objective of this research work is to develop, apply and evaluate state of the art methodical approach to compare and select welding processes in a productive environment based on market requirements of quality and costs for aerospace and nuclear applications. A case study based on several welding processes: SMAW, GTAW, pulsed GTAW, GMAW with CO2 and Argon shielding gases and pulsed GMAW is conducted both from quality and cost aspects. For quality analysis, geometrical aspects of the weld beads and for cost analysis, welding parameters and prices of consumables are considered. In appendage to that, sensitivity analysis of the cost for different variables is also conducted to evaluate the effects of variation in the values of significant variables on the cost.

A Study of the Use of Heat Pipes in Thermal Storage for Cooling

Thermal storage is a popular method of shifting cooling loads to off-peak regions. A new method of discharge is proposed via use of a group of heat pipes inserted in a cold storage tank filled with ice, initially frozen by a separate vapor-compression system. The latent heat of the ice assures circulation in the pipes and heat exchange between warm air and the tank for several hours at a time. An experiment has been conducted by using mixtures of ice and water as phase change material inside the tank. The system is exposed to inlet air at various states of temperature, humidity and varying velocity. The system provides cooling for over 8 hours, and correlations of the system are discussed.