Quality Of Incoming Materials Research Articles

Z-NUMBERS BASED MODELING OF GROUP DECISION MAKING FOR SUPPLIER SELECTION IN MANUFACTURING SYSTEMS

The health of the supply chain, the company's performance, and the quality of the production as well as the success of the entire enterprise, directly depends on the reliability of the company's existing suppliers. Processing enterprises that depend on suppliers are trying to find the best option that will satisfy all customer requirements. With high-quality and inexpensive raw materials, the products produced by the enterprise will largely determine its economic indicators such as revenue, profit, and profitability. Therefore, this enterprise is especially faced with the issue of choosing the most appropriate supplier of resources. Basically, for processing enterprises it is very important to consider the parameters such as quality of incoming materials, terms of supply of raw materials, price of received raw materials, terms of contracts. The challenge in determining of supplier is how to choose reliable suppliers that can maintain supply chain continuity in an environment of ever-increasing instability and uncertainty. For this purpose, a methodology for selecting suppliers using Z-numbers was proposed. Using fuzzy Z numbers in supplier selection, decision-makers can assign values to various criteria in a way that reflects both the uncertainty and the confidence associated with those values. This can lead to more nuanced and robust supplier selection processes, considering a wider range of factors and uncertainties.

A Review of SiC Wafers In-Line Detection Method in Power Device Fabrication

Silicon carbide (SiC) has outstanding advantages such as wide band gap, high electron saturation drift speed, high thermal conductivity, high voltage and high temperature resistance. It is particularly suitable for making high-power devices. The in-line detection of wafers in the manufacturing process of SiC devices can reflect the quality of incoming materials and process quality. It is a very important part of the manufacturing process. SiC wafer’s in-line inspections involves characterization of the epilayer thickness, surface defects and contamination, wafer warping, dielectric and metal film thickness, etching morphology, etc. Various test methods are compared and discussed in this paper and suggestions are given on detection method selection.

A Comprehensive Methodology to Evaluate Losses and Process Variations in Silicon Solar Cell Manufacturing

Novel, high-throughput metrology methods are used in this paper for detailed performance loss analysis of approximately 400 industrial crystalline silicon solar cells, all coming from the same production line. The characterization sequence combines traditional global cell measurements (e.g., current–voltage, Suns- ${V}_{\text{OC}}$ ) with camera-based cell imaging of voltage distribution and power dissipation from photoluminescence and lock-in thermography, respectively. Spatial variations in current collection are visualized using a high-speed external quantum efficiency and reflectance measurement technique. A nondestructive transfer length method (TLM) measurement technique is also implemented, featuring circular TLM structures hidden within the busbars of the cells. The variance of individual loss parameters and their impact on cell performance are quantified for this large group of cells. Based on correlations performed across parameters, recombination losses in the bulk and rear surface of the cell are shown to be the primary limiting factor for the cell efficiency. The nature of these distributions and correlations provide important insights about loss mechanisms in industrial solar cells, helping to prioritize efforts for optimizing the performance of the production line. Additionally, many of the parameters extracted from these techniques can be tied back to incoming material quality issues (e.g., poor bulk carrier lifetime, nonuniform wafer doping) and to individual unit processes (e.g., texturing, phosphorus diffusion, silicon nitride deposition, metallization), allowing the data to be used directly for process control in manufacturing. All of the datasets are made available for download.

Performance analysis of vehicle assembly line using discrete event simulation modelling

The purpose of this paper is to utilise simulation as a decision making tool in a complex manufacturing setup. A vehicle assembly line at an automobile company in India is modelled and analysed to help managers to identify the criticality of different parameters. Conveyor speed, operator fatigue and incoming material quality were selected from a pool of parameters which affect the line output. On the basis of design of experiments (DOE), experiments were carried out to capture the effect of input parameters on the line output. The results from these were further analysed using response surface methodology (RSM) and analysis of variance (ANOVA). The line output was found to be most sensitive to operator fatigue followed by incoming material quality and conveyor speed. This paper provides a structured approach to analyse the vehicle assembly line in an automobile company and provides a suitable tool to the management to analyse the complex functioning of a manufacturing system.

Performance analysis of vehicle assembly line using discrete event simulation modelling

The purpose of this paper is to utilise simulation as a decision making tool in a complex manufacturing setup. A vehicle assembly line at an automobile company in India is modelled and analysed to help managers to identify the criticality of different parameters. Conveyor speed, operator fatigue and incoming material quality were selected from a pool of parameters which affect the line output. On the basis of design of experiments (DOE), experiments were carried out to capture the effect of input parameters on the line output. The results from these were further analysed using response surface methodology (RSM) and analysis of variance (ANOVA). The line output was found to be most sensitive to operator fatigue followed by incoming material quality and conveyor speed. This paper provides a structured approach to analyse the vehicle assembly line in an automobile company and provides a suitable tool to the management to analyse the complex functioning of a manufacturing system.

Low Temperature Fusion Wafer Bonding Quality Investigation for Failure Mode Analysis

In this paper, a brief summary of potential defect formation and failure characteristics for low temperature plasma-assisted Si wafer bonding in correlation to different influencing factors is given. In terms of a failure catalogue classification, these defects are related to incoming material quality variation, wafer bonding equipment and bonding tools issues, or to the choice of inappropriate post-bonding process parameters. To attribute experimentally detected bond defects to its specific root cause requires applying appropriate failure analysis methods, such as e.g. atomic force microscopy, scanning acoustic microscopy, transmission electron microscopy and surface analysis but also strength testing. Practical failure analysis application examples together with new and upcoming methodical developments are presented briefly that support process and technology optimization for future wafer bonded 3D integrated electronic systems.

Quality deficiencies regarding softwood in the pre-fabrication industry for single-family timber houses

The members of the pre-fabricated single-family house industry perceive problems securing the quality of incoming material. Thus the implication is that they need to carry out a quality inspection and adjust the softwood timber as it arrives at their facilities in order to fit the production. Furthermore, due to the intense competition among companies in the pre-fabrication industry, there is a focus on reducing non-value-adding activities such as deficiencies. Consequently, the purpose of this study is to propose a number of propositions regarding quality deficiencies in softwood timber for the pre-fabrication of single-family houses. This study, conducted through interviews based on the theoretical aspects of properties, quality inspection and quality deficiency formulates seven fundamental propositions regarding quality deficiencies in this industry. The main differences among the companies studied are their purchased volume and extent of information and communication technology support in production. This fundamental description of quality deficiencies regarding softwood for the pre-fabrication of single-family houses will enable companies to focus on quality issues with their raw-material suppliers and thereby increase the competitiveness of softwood timber as a construction material in the industry.

Modeling of Heat Transfer and Void Dynamics for the Thermoplastic Composite Tow-Placement Process

Thermoplastic composite tow-placement technology is a nonautoclave consolidation process that offers the potential to significantly reduce fabrication costs by using in situ consolidation as a method for manufacturing large composite components. The temperature history and resulting degree of consolidation directly control the final part quality and are directly affected by the process set points. In this work, series of integrated submodels are developed for predicting the heat transfer and void dynamics within the laminate. The final through thickness void fraction is predicted as a function of process parameters. Experiments are carried out to validate these results for a wide variety of process conditions. The model is used to quantify the relationships between variation of quality of incoming material (e.g., void content ranges 3.1 and 5.5% and final void content gradients. It was found that significant gradients in final void content exist through the thickness and is directly related to processing conditions. Recommendations for process optimization are discussed.

Impact of operations management practices on quality and time‐based performance

Recent research in manufacturing has investigated the impact of enabling operations management (OM) practices on quality and time‐based performance separately. This research investigates the concurrent impact of supply management, human resources, just‐in‐time (JIT) and cross‐functional practices on quality and time‐based performance, in a sample of firms from the automotive components industry. Relationships of 13 individual OM practices with three objective measures of quality performance and two objective measures of time‐based performance were analysed using simple and stepwise multiple regressions. Results indicate that seven of these practices, namely incoming material quality, kanban systems, set‐up time reduction, performance‐based pay and quality training to workers, cross‐functional interactions between design and quality assurance and between production and new product development, have significant synergistic relationships to both quality and time‐based performance. The research supports the argument that there is synergy between quality and time‐based performance capabilities.

Non-Destructive Optical Techniques for Characterizing Semiconductor Materials and Devices

In the information age, communications technology depends on the efficient manufacture of photonic and electronic devices. Optical testing promotes manufacturing efficiency by controlling the quality of incoming materials, providing rapid feedback for process improvements, and analyzing why a product has failed. New, non-destructive optical techniques are being used to measure key properties of semiconductor materials and devices. Optical mapping reveals defective regions in various types of wafers, as well as in semiconductor-based lasers and detectors used in AT&T's lightwave communication systems. New optical testing techniques include optical beam-induced reflectance (OBIR), whose signals are used to map silicon, and spatially resolved photoluminescence (SRPL), which performs high-resolution mapping of III-V semiconductor materials.

A Feasibility Study of JIT Purchasing Implementation in a Manufacturing Facility

The just‐in‐time (JIT) purchasing system has been demonstrated as a mechanism to reduce inventory carrying cost and improve the quality of incoming materials. One major limitation of the JIT purchasing system is that it demands a major change in people′s attitudes and work habits. While leading an organisation towards the complete implementation of a JIT system, management must have creative and innovative ideas to ensure co‐operation of all concerned. A feasibility study of implementing a JIT purchasing system conducted in a large manufacturing plant is reported.

Recent Work in the Fractography of Composite Materials

Fractographic techniques have been increasingly applied to failed specimens in attempts to define micromechanical failure mechanisms in composite materials. This effort can provide useful information relevant to all phases of studies of composite materials. For example, fractographic data obtained from laboratory control specimens can be used in material selection and optimization. Similarly, efficient structural design requires a detailed understanding of the fracture behavior of the material and the modes of failure of the component. Finally, as a production tool, microscopy can be applied to assess the quality of incoming material once key accept/reject features have been identified.

The Performance and Quality Control of Diesel Engine Components

This paper outlines methods developed to control the quality of incoming materials and finished components with emphasis on the performance that is ultimately required from them. The examples given are taken from diesel engineering but the basic ideas apply to all industries whose final products consist of an assembly of components which are complete in themselves. The quality control of materials and components fills an important role in ensuring that the technical requirements written into a specification by a designer are met by suppliers. The author outlines various techniques developed in his company to achieve this. The paper has two main sections: ( a) quality control of incoming materials, and ( b) performance control of components. The first part deals with the controls established for cast-iron components of various sizes ranging from bedplates and columns weighing about 20 tons to piston rings weighing less than one pound. Ultrasonic testing is briefly discussed as also is the material specification for white metal bearings. The second part of the paper gives examples of performance testing of a number of diesel engine components together with brief details of some of the test rigs that have been developed to carry out the tests. Some of the components discussed in this section are piston rings, crankshafts, camshafts, cams, and fuel injection equipment.