In-Situ direct observation was used to observe the liquation in an Inconel 617. High-Temperature Confocal Laser Scanning Microscopy (HT-CLSM) was used to observe the phenomena. Experiment was perform at 1330°C wi...
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The manufacturing industry is facing many new challenges including redefined customer expectations in the E-Commerce era. The consumer is now better informed, more demanding and has higher expectations in terms of pro...
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This paper addresses the problem of process plan generation and optimization for dual-spindle/dual-turret CNC mill-turn centers (commonly referred to as four-axis turning centers) that are capable of both parallel and...
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Sapphire wafers are widely used as the substrates for fabricating GaN light-emitting diodes (LEDs). The quality of LEDs depends directly on the quality of the sapphire wafers. A series of machining processes is requir...
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Sapphire wafers are widely used as the substrates for fabricating GaN light-emitting diodes (LEDs). The quality of LEDs depends directly on the quality of the sapphire wafers. A series of machining processes is required to turn sapphire barstock into wafers with the desired geometry and surface quality. This paper reviews the literature on various machining processes for sapphire wafers: slicing (including outer diameter cut-off grinding, inner diameter cut-off grinding, loose abrasive multi-wire sawing, fixed abrasive slicing, and fixed abrasive multi-wire sawing), flattening (including lapping and grinding), and surface finishing (including mechanical polishing and chemical mechanical polishing). New machining technologies are also introduced.
To remain competitive in the global marketplace, manufacturing companies are transforming their organizational structure and operational philosophy from one based on vertical-integration to one based on core competenc...
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With the integration of multiaxis layered manufacturing and material removal (machining) processes, a hybrid system has more capability and flexibility to build complicated geometry with a single setup. Process planni...
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With the integration of multiaxis layered manufacturing and material removal (machining) processes, a hybrid system has more capability and flexibility to build complicated geometry with a single setup. Process planning to integrate the two different processes is a key issue. In this paper, an algorithm of adaptive slicing for a five-axis Laser Aided manufacturing Process (LAMP) is summarized that can generate uniform and non-uniform thickness slices. A method to build a non-uniform (thickness) layer that utilizes two processes is presented, and an overall algorithm for integration is described. The newly developed algorithm implemented in the process planning helps the hybrid system build parts more efficiently.
A special neural network topology has been developed that compensates for friction in precision, position controlled mechanisms. A major contribution is that knowledge of the friction's form is used to determine t...
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A special neural network topology has been developed that compensates for friction in precision, position controlled mechanisms. A major contribution is that knowledge of the friction's form is used to determine the neural network's structure. This unique approach solves network sizing and weight initializing problems. The friction model is used for feedforward decoupling of friction-induced torque. The neural network also explicitly incorporates inertia compensation and linear feedback control. Another contribution is a demonstration of the trajectory dependence of static friction compensation with a discrete time controller. The authors include both the theoretical formulation and practical implementation results for the control of a commercial DC motor having a significant amount of static friction.< >
Proper design of castings is essential to avoid casting defects that cannot be eliminated by design of tooling and process parameters. Shrinkage porosity is one of the defects which usually occur at casting junctions ...
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ISBN:
(纸本)9781618390578
Proper design of castings is essential to avoid casting defects that cannot be eliminated by design of tooling and process parameters. Shrinkage porosity is one of the defects which usually occur at casting junctions and cannot be easily eliminated. Currently, designers use rules that were established based on experience and intuition and are not supported by proper experimentation. In this paper an approach to design and optimize design of casting junctions using a database of mathematical models is presented. The mathematical models give relationships between porosity and the junctions' dimensional features. To illustrate this approach, a mathematical model for a V-junction has been developed using Design of Experiments (DoE) and regression analysis techniques. The experimental runs for the study are established using a D-optimality criterion and conducted using MAGMASoft, comprehensive software for casting simulation, for measuring porosity in casting junctions. The simulations carried out in MAGMASoft are validated by comparing its results with experimental results from previous studies. The mathematical model is then developed by applying regression analysis. The results of the model have been validated and found to agree with both the experimental and the validation simulation experiments.
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