Papers by Keyword: Step

Abstract: Physical vapor deposition (PVD) has been an important method to synthesize metallic nanorods during the past two decades. Based on the main physical process of crystal growth, this letter made a growth model of metallic nanorods with kinetic lattice Monte Carlo (KLMC) method and studied the effects of three-dimensional (3D) Ehrlich–Schwoebel (ES) barrier during the metallic nanorods growth. According to the simulation results, a large 3D ES barrier affects the surface morphology apparently. With analyze the simulation results, 3D ES barrier promotes the step formation and increases the step height greatly, and it is the main factor of metallic nanorods formation.

Abstract: ISO 14649 standard, commonly recognized as STEP-NC is a data model interface for computer numerical controllers. STEP-NC goes much further that G codes and has a more comprehensive data model that overcomes the lack of process information in ISO 6983 files (G codes programming). The STEP compliant approach brings the possibility to integrate the machine controller to the overall enterprise information network, with the intention of having bi-directional data flow. This will provide the novel capability for upstream feedback of information from the numerical controller to the design and process areas in the process planning and manufacturing. This paper presents the key concepts of the proposed STEP Convertor of the STEP-CNC Mapping System. The objective of the main system is to take a generic STEP file as the input to drive a CNC machine tool. The main system is broken down into two main sub-systems, STEP Convertor and STEP-NC Translator. This paper will focus solely on the information structure and conceptualization of the STEP Convertor.

Abstract: The aims of this research is to build CAIP systems on OMM operation which have an ability to measure workpiece automatically based on drawing data from design division at a machine. The flow of information between each part becomes important as the design of the drawing data from design division to production division or quality control. CAIP system (Computer Aided Inspection Planning) is expected to ensure the flow of drawing information to quality control without any changed even though the amount of data that a lot. CAIP system use early drawing data from the design division. The type of drawing data which is used by each CAD software is STEP drawing data. STEP data consists of products information such as surface geometry, line, point, and direction of the vector surface. The information that can be used to build a CAIP system is a feature. Therefore, a feature reconstruction process is necessary based on the data STEP geometry information. Feature types which is used in this study are a type of box primitive feature. A Probe, a measuring instrument, can be operated in CMM (Coordinate Measurement Machine) and CNC machine. A product measuring on CNC machine during or after machining process called OMM (On Machine Measurement) operation. As a result, measuring can be performed without moving the product from the machine. In this research, 5 Axis CNC machine with Heidenhain DMU150 iTNC530 controller is used.

Abstract: In future technology in the field of advanced manufacturing, an open architecture controller in CNC system is studied. In this paper, the LabVIEW software platform is chosen and software realization methodology for the CNC system is determined for this application. This research project aims to meet the requirement of open architecture to create a CNC system based on new ISO standards of ISO 14649 and ISO 10303. As a result, open 3-Axis Mill CNC system based on component software reuse technology successfully developed. Two case studies of ISO 14649 (example 1 and example 2) were carried out through this developed system.

Abstract: Component model information share is the premise of virtual assembly, but tranditional Component 3D model is not the suitable data format used on Intenet. Realization the transformation from tranditional 3D data to Web-enable data base on STEP standard is feasible. In this paper, we discuss and resolve several problems, such as: Mapping between the EXPRESS data model and the RDBMS, Lexical analysis of STEP file, the tansformation form STEP file to data-base file.

Abstract: This paper demonstrates methods to recognize 3D designed features for virtual environments and apply them to Virtual assembly. STEP is a standard of Product data Exchange for interfacing different design systems, but it cannot be used as input for virtual environments. In order to use feature data in virtual assembly environments, main data source from a STEP file should be recognized and features should be re-built. First, Attributed Adjacency Graph (AAG) is used to analyze and express the boundary representation; second, a feature-tree of a part is constructed; third, using the AAG and feature-tree as inputs, we analyze and extract of features with a feature recognition algorithm; finally, various levels of detail of object geometric shapes is built and expressed in XML for virtual assembly applications.

Abstract: A two-dimensional model is presented in this article to study the transient radiative transfer phenomena involved in a participating medium subjected to short pulse collimation. The model assumes the medium bounded by diffusely emitting and reflecting boundaries, one of the boundaries is irradiated with a short pulse collimated beam. The finite volume method is applied to solve the transient radiative transfer equation governing the physical phenomena. The fully implicit scheme is used to discretize the transient term. In the proposed approach, intensity can directly be evaluated by solving the governing transient radiative transfer equation. The effects of scattering albedo and emissivity on the transmitted and reflected flux are studied. The performance of two different spatial schemes: STEP and CLAM are also been tested. It is seen that the CLAM scheme gives results to a greater accuracy and hence, correctly predict the speed of photon whereas STEP scheme over predicts the same.

Abstract: Based on the Donnell’s approximations of the thin shell theory, this paper presents solutions for the problem of free non-axisymmetric vibration of stepped circular cylindrical shells with cracks. The shell under consideration is sub-divided into multiple segments separated by the locations of thickness variations. It is assumed that at the jth step there exists a circumferential surface crack with uniform depth c_j . The influence of circular cracks with constant depth on the vibration of the shell is prescribed with the aid of a matrix of local flexibility. The latter is related to the coefficient of the stress intensity known in the linear fracture mechanics. Numerical results are obtained for cylindrical shells of stepped thickness containing cracks at re-entrant corners of steps. Shells with various combinations of boundary conditions can be analyzed by the proposed method. Furthermore, the influences of the shell thicknesses, locations of step-wise variations of the thickness and other parameters on the natural frequencies are examined. The results can be used for the approximate evaluation of dynamic parameters of cylindrical shells with cracks and flaws.

Abstract: The Integrated Evaluation Platform for SiC wafers and epitaxial films is established and provide TDDB reliability data such as Q_bd. Accumulated numerous Q_bd data derived from the platform shows three discrete universal distributions (D1>D2>D3) mainly affected by step bunching. On the fairly flat surface, locally spreading step-bunching area formation is caused by the scratches on the CMP surface. The step-bunching area contains large number of step-bunching lines, which correspond to trapezoid-shape defects, stretching in a low along the scratches. Only the downstream bases of the trapezoid-shape defects degrade the Q_bd into D2 from D1 on the flat surface without step bunching.

Abstract: This research explored ISO 14649 together with ISO 6983 and utilize STEP-NC in overcoming the problems of G & M code and at the same time take advantage of the current advances in computing and controllers. A new STEP-NC Code Generator called Milling STEP Coder, which focuses on the milling process that are able to generate STEP-NC codes based on ISO 14649 Part 11 was developed. This system also has the capabilities to visualize the STEP-NC codes generated in a parent to child relationship tree-view structure, as well as give an image visualization of how the end machining will appears. The developed Milling STEP Coder uses Software Prototyping Model as its software development methodology, instead of the normal waterfall model, as prototype is a valuable mechanism for gaining better understanding of the system requirements. A small-scale mock up of the system was developed following an iterative modification process. The advantages of the proposed Milling STEP Coder program was verified and evaluated. The Milling STEP Coder can generates STEP-NC codes through a STEP-NC compliant interface and will give industries and academician more in-depth understanding and confidence to make the switch from G & M code to STEP-NC.