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Cyberspace odyssey (CSO) is a novel serious game supporting computer networking education by engaging students in a race to successfully perform various cybersecurity tasks in order to collect clues and solve a puzzle in virtual near-Earth three-dimensional space. Each team interacts with the game server through a dedicated client presenting a multimodal interface, using a game controller for navigation and various desktop computer networking tools of the trade for cybersecurity tasks on the game's physical network. Specifically, teams connect to wireless access points, use packet monitors to intercept network traffic, decrypt and reverse engineer that traffic, craft well-formed and meaningful responses, and transmit those responses. Successful completion of these physical network actions to solve a sequence of increasingly complex problems is necessary to progress through the virtual story-driven adventure. Use of the networking tools reinforces networking theory and offers hands-on practical training requisite for today's cyber operators. This article presents the learning outcomes targeted by a classroom intervention based on CSO, the design and implementation of the game, a pedagogical overview of the overall intervention, and four years of quantitative and qualitative data assessing its effectiveness.

Changes in the geopolitical landscape and increasing technological complexity have prompted the U.S. Military to coin the terms Multi-Domain Operations (MDO) and Joint All-Domain Command and Control (JADC2) as over-arching strategy to frame the complexity of warfare across both traditional and emerging warfighting domains. Teaching new concepts associated with these terms requires both innovation as well as distinct education and training tools in order to realize the cultural change advocated by senior military leaders. Battlespace NextTM (BSN) is a serious game designed to teach concepts integral to MDO and initiate discussion on military strategy while conserving time, money, and manpower. BSN, a Collectable Card Game (CCG), is engineered to provide an engaging learning tool that educates on capabilities in a multi-domain conflict. This paper proposes an extensible game framework for modeling and reasoning about MDO concepts and presents our empirical feedback from over 120 military play testers evaluating a moderate to difficult version of the game. Results reveal the game teaches MDO concepts and delivers an engaging, hands-on learning experience. Specifically, we provide evidence it improved military readiness in seven areas of MDO in at least 62% of participants and 76% of respondents reported they enjoyed playing the game.

Mold components for producing a cycling helmet are one of the most complex parts encountered in 5-axis NC machining. One important factor namely machining direction is used not only for checking collision, but also for reducing machine setup and shaping surface with low curvature variations. This paper focuses on how to minimize the total number of machining direction in 5-axis NC machining of cycling helmet’s mold components. In the proposed method, the machining direction candidates are generated using a regular placement method. V-maps are also used to select the machining direction through cascade filter of V-maps. Genetic algorithm is also used in order to identify the initial machining direction. Moreover, blockage solver and agglomeration method are applied in sequence to update the machining direction results. Additionally, to evaluate the performance of the proposed method, a CAD model for the cycling helmet mold components is created and used as a model of implementation. The computational result shows that the CAD model can be machined using the minimum number of machining directions. A 5-axis NC machine is also used to really produce the mold components.

This paper addresses the problem of scalable location-aware distributed indexing to enable the leveraging of collaborative effort for the construction and maintenance of world-scale maps and models. These maps and models support numerous activities including navigation, visual localization, persistent surveillance, and hazard or disaster detection. We approach a solution through the creation of PeerAppear, a location-aware framework for peer-to-peer indexing, search and retrieval. Due to the dynamic nature of the world, the problem of constructing and maintaining relevant world-scale models generally requires significant effort to be spent on mapping. PeerAppear offers a decentralized solution which enables the leveraging of collaborative effort through the implementation of a peer-to-peer middleware framework which automates the indexing and sharing of sensed geospatial information captured and stored in the local repositories of participants. The PeerAppear network achieves scale through a Kademlia-like overlay network which indexes data based on location by adapting Google’s S2 hierarchical geographic segmentation scheme to a globally addressable distributed geographic table. Our communications primitives allow search queries to be formed and executed, enabling the discovery of information published in a specified geographic area. An evaluation of the framework is presented demonstrating excellent retrievability of published data, logarithmic efficiency and global scalability.

Serious games provide a method for teaching students in an engaging, non-threatening way. To be useful educational tools, these games need to be designed with the lesson objectives in mind. This paper uses the Game Design Matrix to design a game from learning objectives. The lesson objectives focus on software development, security and operations (DevSecOps). DevSecOps requires judging the cost and risk trade offs between secure and unsecured software aspects including code, data and usability; devising a strategy to produce a system under threat; comprehending that partial security may equate to no security; and identifying examples of insecure code and methods of mitigating it. These lesson objectives combined with the teaching environment drive design decisions that produce a game that fits well into a graduate level course in secure software design and development. We evaluate the game in a graduate course on secure software design and development. Learner surveys confirm that DevSecOps conveys the learning objectives in an engaging way.

Determination of pull directions for a freeform surface is a challenging problem because the number of normal vectors is unlimited for such type of surfaces. Consequently, researchers generally convert a freeform surface into planar faces to limit the number of normal vectors. This paper presents an approach using cascade filters of visibility maps to determine feasible pull directions for freeform surfaces such that the required accuracy is retained. Pull direction candidates are first generated using a modified regular placement method. Normal vectors are then extracted by a sampling box, and the number of normal vectors is optimized through a numerical approach. Significant normal vectors are then selected by a modified Barycentric method. A cascade filter of the visibility map is built using these vectors and used for the selection of feasible pull directions. A minimum number of sliders and cavities in molding are finally achieved using a clustering algorithm based on maximum intersections of visibility maps. A real-life part is created using commercial CAD software for performance evaluation of the proposed algorithm.

As society becomes more dependent upon computer systems to perform increasingly critical tasks, ensuring that those systems do not fail becomes increasingly important. Many organizations depend heavily on desktop computers for day-to-day operations. Unfortunately, the software that runs on these computers is written by humans and, as such, is still subject to human error and consequent failure. A natural solution is to use statistical machine learning to predict failure. However, since failure is still a relatively rare event, obtaining labelled training data to train these models is not a trivial task. This work presents new simulated fault-inducing loads that extend the focus of traditional fault injection techniques to predict failure in the Microsoft enterprise authentication service and Apache web server. These new fault loads were successful in creating failure conditions that were identifiable using statistical learning methods, with fewer irrelevant faults being created.

In computer-aided design for moldings, automatic generation of parting curves is a crucial design task that has an influence on the entire mold structure. This article proposes a hybrid approach for determining the parting curves of free-form computer-aided design models. Based on the analysis of the geometric properties of specific entities and mathematical conditions, different sets of moldable surfaces for two-half molds and side cores are identified. All surfaces that do not contribute to the parting curves can be subtracted from these surface sets. The proposed parting curve is generated based on the combination of both the outermost boundary edges and the visible silhouette segments of the relevant surfaces. By the techniques of silhouette detecting, edge projecting, and ray testing, the proposed algorithm overcomes the problems found in conventional research that cannot guarantee that the outermost curves generated are the actual silhouette of a free-form surface. In addition, by eliminating all irrelevant surfaces and without using the surface approximation method, the proposed approach achieves the goals of obtaining high accuracy coupled with high performance. Two examples of industrial models are used to demonstrate the performance and robustness of the proposed algorithm. The approach is generic in nature, which allows it to be applied to any complex geometry in three-dimensional mold design.

A new slicing algorithm that uses multiple sets of cutting planes to automatically determine parting curves for three-dimensional parts is proposed. In this algorithm, one set of cutting planes is used to generate the slicing profiles, and two others are used to determine the intersection points with the inner and outer loops of the parting curves. The algorithm provides a highly effective solution for handling complicated models that contain free-form surfaces. The features of the algorithm are highlighted in three case studies using tessellated geometry in STL file format as the input. The resultant parting curves overcome many problems inherent in the current methods and can be used by various downstream computer-aided design systems for three-dimensional mold design.

Multi-piece molding technology is an important tool in producing complex-shaped parts that cannot be made by traditional two-piece molds. However, designing multi-piece molds is also a time-consuming task. This paper proposes an approach for automatic recognition of mold-piece regions and parting curves for free-form CAD models. Based on the geometric properties of objects and mathematical conditions of moldability, a collection of feasible parting directions is formed from which the sets of visible-moldable surfaces are identified for each parting direction. Moldable surfaces that are partially visible to a particular parting direction are recognized and divided into fragments by silhouette detection and edge extrusion. A set of criteria is proposed to arrange tentative fragments, which can be simultaneously visible to several parting directions, into appropriate regions for mold pieces. Finally, the parting curves for mold pieces are extracted from the corresponding mold-piece regions. The proposed algorithm overcomes the problems found in previous multi-piece molds and at the same time achieves high accuracy and high performance. Examples of industrially complex models are used to demonstrate the performance and robustness of the proposed algorithm. The approach is generic in nature, allowing its application to be extended to any complex geometry in 3-D mold design.

The Internet of Things (IoT) era envisions billions of interconnected devices capable of providing new interactions between the physical and digital worlds, offering new range of content and services. At the fundamental level, IoT nodes are physical devices that exist in the real world, consisting of networking, sensor, and processing components. Some application examples include mobile and pervasive computing or sensor nets, and require distributed device deployment that feed information into databases for exploitation. While the data can be centralized, there are advantages, such as system resiliency and security to adopting a decentralized architecture that pushes the computation and storage to the network edge and onto IoT devices. However, these devices tend to be much more limited in computation power than traditional racked servers. This research explores using the Cassandra distributed database on IoT-representative device specifications. Experiments conducted on both virtual machines and Raspberry Pi's to simulate IoT devices, examined latency issues with network compression, processing workloads, and various memory and node configurations in laboratory settings. We demonstrate that distributed databases are feasible on Raspberry Pi's as IoT representative devices and show findings that may help in application design.

US Air Force satellite ground stations require significant manpower to operate. To improve operating efficiencies, the Air Force seeks to incorporate more automation into routine satellite operations. Interaction with autonomous systems includes not only daily operations, but also the development, maintainability, and the extensibility of such systems. This paper presents challenges to Air Force satellite automation: 1) existing architecture of legacy systems, 2) space segment diversity, and 3) unclear definition and scoping of the term “automation.” Using a qualitative case study approach, we survey comparable non-satellite operation domains (Industrial Control Automation and Software Testing) that have successfully integrated automation, and other satellite operation enterprises (NASA Goddard, Naval Research Laboratory, European Ground Station National Institute for Space Research in Brazil) to identify common themes and best practices. From this insight, we recommend that future satellite operation ground stations encourage the use of layered architectures, abstract satellite operation processes, and integrate simulators in future systems as concrete implementations of this common operating platform.

This paper provides a design technique of support for being applied in fast fabrication on plastic prototype, the plastic part developed through the computer aided design (CAD) can be rapidly fabricated by a CNC machining center without needs of any specific jigs or fixtures, the function provided is similar to a rapid prototyping (RP) machine used for fabricating the sampling part. By the testing result, the provided design technique of support can not only be applied in the part required for a dual-surface (or multiple-surface) processing, but also applicable for fabricating the part having thin housing. As such, this paper provides another economical and efficient option besides the RP.

Parting curve selection and evaluation plays an important role in mold design. Multiple criteria decision-making (MCDM) is an effective tool for evaluating and ranking problems involving multiple criteria. In order to select suitable parting curve, several criteria need to be taken into account. Therefore, this paper proposes an extension of fuzzy MCDM approach to solve parting curve selection problem. In the proposed model, the ratings of alternatives and importance weights of criteria for parting curve selection are expressed in linguistic terms. The membership functions of the final fuzzy evaluation value in the proposed model are developed based on the linguistic expressions. To make the procedure easier and more practical, the normalized weighted ratings are defuzzified into crisp values by using a new maximizing set and minimizing set ranking approach to determine the ranking order of alternatives. An example of parting curve evaluation and selection is given. The results show that the proposed approach is very effective in selecting the optimal parting curve for the molded part. Finally, this paper compares the proposed approach with another fuzzy MCDM approach to demonstrate its advantages and applicability.

Improper tool orientation planning often causes four typical types of inappropriate four-axis tool paths. They are included: 1. Severe changes of tool orientations occur, 2. Reversions of tool orientations exist, 3. Discontinuous tool paths occur, 4. Gouging. After explore the common methods of the present four-axis machining and their restrictions, the research proposes a hybrid tool orientation planning (HTOP) method to improve the above shortcomings and to get smoother rotary tool paths. An example is done in the last to verify its feasibility.

Since different types of 5-axis milling machines have their own unique rotation mechanisms, the solutions developed to generate numerical control (NC) data are traditionally targeted toward specific mechanisms and are obtained via specific methods, normally resulting in complex algorithms. In order to resolve this problem, this paper proposes an instinctive method to convert cutter location (CL) data to NC data for non-orthogonal table-type 5 axis machines. The rotational angles of the two rotational axes can be easily derived from the tool-orientation vector, and the coordinates of the three linear axes in the NC data can be easily derived from the rotational angles and coordinates of tool position. Even more, this method enables the development of a generic algorithm for the rotation mechanism of any 5-axis CNC milling machine.

In computer-aided design for moldings, automatic generation of side-cores is a crucial design task that has an influence on the entire mold structure and manufacturing cost. This paper proposes a synthetic approach for creating the side-cores of free-form NURBS surface models. Based on the geometric properties of entities, surfaces of undercut features which are molded for side-cores are identified. After determining the withdrawal directions for each group of undercut’s surface features, the number of side-cores is optimized. The heads and the bodies of side-cores are finally obtained through the combination of the Boolean operation and 3D oriented extrusion. The algorithm is efficiently for both protruded and indented portions of undercut features. A complex industrial part is used to demonstrate the performance and robustness of the proposed algorithm. Since the approach is generic in nature, it is easy to be applied to any complex geometry in 3D mold design.

When operating a 5-axis linear cutting command G01, the controller automatically inserts point data between two NC blocks in a linear distribution fashion, and then drives the cutter along these inserted points. If a simultaneous 5-axis machining is initiated, and CL data is directly transformed one-to-one into NC data, and then cutting is performed directly without having the 5-axis controller inserting any points between NC blocks, its processing path will deviate from the original plotted path. In fact, the processing path is no longer a straight line, but a curve line. This study proposes a method to increase CL interpolation points to automatically rectify the path deviation. The extent of research of this study comprises: (1) Transforming CL data into NC data (2) Programming tool orientations (3) Obtaining all CL interpolation points and their tool orientations (4) Generating NC data.

Combining Taguchi experimental design and fuzzy theory, this research aims to develop a multi-objective algorithm to determine the optimal design parameters for the driving springs in a slide cover hinge. The goal is to determine parameters that will meet the two basic requirements of the spring that would generate adequate reaction force but minimize maximum stress. This research applies finite element method to calculate the reaction force and maximum stress of a deformed spring. Meanwhile, the Taguchi method, which could dramatically reduce the number of experiments, is used to determine the optimal design parameters for the spring. Experimental results suggest that if the maximum stress is minimized, the reaction force will decrease, resulting in the autonomous release of the slide cover hinge; if adequate reaction force is achieved, the maximum stress would exceed the design standard. Therefore, this research employs fuzzy theory to achieve multi-objective as “minimization of maximum stress” ...

The determination of side-core for plastic moldings plays an important part in design process. Numerous studies have been investigated for side-cores recognition in literature. However, most of the existing methods have been developed based on the side-core surfaces of one region are known. In fact, it is difficult to identify relevant surfaces of one region. This study proposes a new algorithm of relevant surface attribution (RSA) based on topological relationship and V-map to automatically identify relevant surfaces of a side-core region. Then, the proposed approach defines the shape of side-core region as bounding surfaces and side-core direction. Finally, case studies are used demonstrating the applicability and usage of proposed approach.

This paper aims to study the use of the superimposition scheme to quickly plan the bending sequence in a progressive die design for a sheet metal part which contains bending and shearing features, and to determine the best among multiple feasible solutions. The biggest problem in applying superimposition is that the possible solutions form an excessive solution space when multiple punches are used. In order to solve this problem, this paper introduces three steps: strip preparation, punch layout, and layout evaluation. The punch layout uses clustering rules to classify punches into five groups: prior use (the punches must be used first), posterior use (must be used last), simultaneous use (must be used together), sequential use (certain punches must precede others), and exclusive use (must not be used together). It then derives the compatible sets for each punch, followed by an expansion of the number of punches and punch layout, in order to obtain every feasible solution. The layout evaluation adopts a m...

This paper proposes a new slicing approach that uses multiple sets of cutting planes to automatic determine parting lines and boundaries of undercuts of complex CAD parts for the multi-piece molds design. In this algorithm, the group of feasible parting directions is first collected and three sets of cutting planes are then formed based on the primary parting direction. One set of cutting planes is used to generate slicing profiles, and two others are used to extract intersection points passed through by parting loops and boundaries of undercuts. The result shows that the proposed parting lines are suitable to obtain parting surfaces and construct the entire mold-pieces. The algorithm provides a highly effective solution for handling many complex industrial parts.

This paper aims to study the methodology of building the knowledge of planning adequate punches in order to complete the task of strip layout for shearing processes, using progressive dies. The usage of superimposition of punches for planning strip layout is widely accepted among progressive die designers; however the huge number of combinations of punches may turn this easy-to-understand process into a nightmare. The proposed methodology uses die design rules and characteristics of different types of punches to classify them into five groups: prior use (the punches must be used first), posterior use (must be used last), compatible use (may be used together), sequential use (certain punches must precede some others), and simultaneous use (must be used together). With these five groups of punches, the searching space of feasible designs will be greatly reduced, and superimposition becomes a more effective method of punch layout. The superimposition scheme may generate many feasible solutions. Although none...

This research proposes the methodology of using the 3D CAD model of a slide-hinge spring as the basis to analyse the stresses and reaction forces, and implementing Taguchi method to find the optimal parameters of the spring. Firstly, 3D meshes are generated out of the 3D CAD model. In accordance to the mechanism characteristics of the slide hinge, primary data for engineering analysis are determined, including mesh properties, material properties, boundary conditions, contact definitions, and iterative procedure. MARC, a well-known CAE software, is then used to find von Mises stresses and reaction forces of the spring during its movement in a slide hinge. In order to prevent plastic deformation and damage of the spring, the Taguchi method is adopted in this paper to reduce the maximum stress during spring movement. All details of optimizing the dimensional parameters of the spring will be discussed in the paper, including the determination of control factors and their levels, setup of orthogonal a...

Artificial hip replacement arthroplasty has been developed and practiced in orthopedic surgery for many years. The conventional method is total hip replacement system consisting of a femoral stem and head and acetabular socket. However the high stress between the femoral head and the acetabular socket often causes stress shielding effect to occur and consequently results in the failure of the artificial hip replacement surgery. This study aims to provide an alternative solution to the aforementioned problem with hip resurfacing surgery. The CAD model concept for the design of resurfacing hip joint system is to eliminate stress shielding effect caused by conventional stemmed hip joint system. In this study, finite element analysis is employed to compare resurfacing hip joint system, stemmed hip joint system, and natural hip joint with regard to medial and lateral femur stress, and strain distribution on the femur in order to discuss the applicative characteristics of the two different surgical proc...

This paper proposes a two-step process which uses the knowledge gathered in sheet-metal manufacturing practice as the basis to find proper layouts of strip in progressive dies. In the first step, manufacturing knowledge is used to formulate various rules to cluster the punches into five categories for reducing the searching space of feasible layouts. Evaluation functions are then applied to find the better ones from the feasible layouts. This two-step process provides a new approach to solving the problem of “explosive combinations” in strip layout design

Nowadays in many cases of product shape modification where no original design drawing is available, equipments like coordinate measuring machine and rapid prototyping machine are very often employed, together with modification software, to attain integrated technology for product shape modification in a relatively short period of time. This study conducts the measurement of the outer shape of existing complex model and puts it through different steps such as data points acquisition, surface filling, and surface fitting. As the collision testing of physical object is not available, CAE software ANSYS Workbench is therefore used for contact analysis to determine the area of stress concentration after the collision for consequent modification of the shape. Contact analyses before and after the modification are then compared. In the last step, the modified geometric shape is used by the rapid prototyping machine to produce a product prototype for the manufacturer to display. This modification procedure can be widely applied in car manufacturing industry, mobile phone industry, product form design related industry, and so on.

With the advance of science and medicine, life expectancy of human beings becomes increasingly higher. Never the less, human bones and joints very often could be impaired and cause pain due to degeneration, osteoporosis, and long-term use. With the advance in science and medical engineering, artificial joint replacement can greatly relieve pain and improve the functionality of the joint in cases of severe joint diseases. X-ray Computed Tomography (abbreviated CT) is a medical imaging test that employs x-ray to penetrate human body and x-ray sensors positioned at the opposite side of the body to receive the x-ray. The x-ray images are then processed by computer to create tomography, but errors in measuring accuracy none the less could cause distortion to the computed tomography. Previous concept of designing artificial joint component has been existent in simulated situation, and there are many insurmountable technical difficulties in the practice of reconstruction which results in design flaw in the geometric shape of artificial joint body and increases the risk of failure. This study uses empirical method to determine the shape and size that is closest to human bone, and aims to achieve accuracy error compensation by means of correction mode and consequently improve the accuracy of reconstructed artificial joint and lower the risk of failure in artificial joint arthroplasty.

Consumer electronics are ever more sophisticated in terms of esthetics and design. Due to mass production, the required sampling quantity for quality inspection of products has surged considerably. As such, learning how to utilize the appropriate device and methodology to accomplish free-form surface measuring in an efficient, precise, and timely way has become a very important topic for quality control of the design of consumer electronics. Focusing on the overlap interference problem of fan blades produced in the axial fan blades, this research proposes a geometric calculation algorithm and calculates the suitable measuring orientation, which can be used to evade the interference area of the surface of each fan blade, so as to achieve the objective of automatic measuring. Meanwhile, this research develops a visual software system to simulate the actual optical scanning orientation of non-contact measuring, intending to let users observe the optical scanning orientation of fan blades and estimate the measuring results through the simulated images. Finally, by the way of real measuring, this paper proves the feasibility and convenience of this research.

This research paper presents an analysis of the undercut interference and inclination interference caused by complicated 3D workpiece during measurement. The objective of this research is to propose a solution to the collision between measuring probe and workpiece for the purpose of automation and interference-free measurement. The fundamental procedure is based on the 3D CAD model of workpiece and five-axis coordinate measuring machine (CMM) measuring facility to generate an interference-free stylus orientation through three phases—adjustment of inclination angle under linear contour, adjustment of inclination angle under non-linear contour, and definition of rotation-free angle. Such manner not only solves the interference problems but also incorporates the minimization of counts of measuring probe rotation. In terms of methodology, the research adopts projection of cutting plane to determine the interference status of the measuring point, and based on the measuring inclination angle on the proposition of self-intersected contour and cross-intersected contour concepts, the range of safe rotation range can be determined by sweeping operation. Following the presented methods and procedures, the five-axis CMM simulation system for automated measurement is finally developed to validate the feasibility of proposed solution.

As living standards have improved, the requirements of appearance modeling variables have also increased. Although several CAD systems can design and modeling needed products with complicated geometric, but the questions of measuring methods and workpiece error-detection are also growing. For the contact measuring method, besides measuring collision and probe orientation, the sampling points and their distributed locations are the important factors that influence measuring time as well as precision. In this paper, the sampling statistics technique was used to calculate the minimum number of sampling points, which will tally the contour tolerance requirements of the measured surface. Next, the suitable locations for sampling points will be carried out using the one-half sampling distribution method. Finally, the 2D space picture of measuring characteristic of five-axis CMM (CMM-space) was developed for measuring probe’s orientation in the measuring process. As a result, an algorithm of measuring characteristic matrix of five-axis CMM (CMM-matrix) and the minimum times of the measuring probe’s placement was derived to reduce the measuring time and improve the measuring efficiency.

Turbine blades are widely used in turbo-engines and generators. The complex geometry of turbine blades and the limited space between two adjacent blades cause difficulties in both machining and inspection. This paper is focused on the use of a 3-axis coordinate measurement machine (CMM), together with a dividing head with two rotational axes, to undertake the task of precision inspection of turbine blades that surround the periphery of an axial wheel. Based on the geometrical relationship between the probe stylus and the turbine blades, a methodology is proposed to find the angle of rotation of the axial wheel when a collision is likely to occur between them. Other issues related to system implementation are also discussed in this paper, including: (1) Data transformation from the turbine blade’s geometric model to the CMM control codes, (2) Planning of the traveling paths of the stylus, and (3) Analysis of the measured data.

This study aims to build a triangular-mesh model directly from scanned 3D data points, which then generate the stereolithography (STL) file, thus avoiding the troublesome task of producing a CAD model. Accuracy of the triangular-mesh model is achieved because the pitch between data points is generally very small. In addition, the paper proposes a multi-nozzle path algorithm to increase both spraying efficiency and part accuracy. The processing procedure includes: (1) Establishing the triangular-mesh model from scanned data points, which are retrieved by means of contact- or non-contact type measuring machines as well as developing the algorithm to add the radius of the probe automatically. (2) Equally slicing the triangular-mesh solid model and plan spraying paths. (3) Determining the amount and diameter of nozzles appropriate for each slice to generate multi-nozzle spraying paths.

Traditional rapid prototyping (RP) uses one nozzle, with a single‐diameter, to conduct spraying of a RP part. The process is usually time‐consuming and inefficient. To improve the traditional method, this research aims to develop a new approach by planning an adaptive path and applying it to the spraying process of every slice. Each accurately sprayed slice then adds one upon another to form a RP part. The processing includes four steps, which will help to produce the adaptive path file, which can be input into the RP machine to make a prototype.

This study examines the feasibility of using open regions and vector fields to determine the appropriate tool orientation in five-axis NC machining of cavity regions with undercut areas. The first step involves slicing the to-be-machined surface into thin layers and then comparing those layers to find the position of the undercut; that is, the position of open region. Two-staged checking is proposed to determine the tool orientation that prevents collision. The two stages are initial tool orientation and collision inspection. An initial tool orientation is obtained by assessing the angle of the vectors determined by data points of contours of the open region and cutter contact (CC) points. If a collision is found in the initial orientation, then the tool orientation must be revised until no obstacles are generated from the collision.

The very first step in the process of reverse engineering is to acquire data points by measuring the points on the surface of an object. The fineness and correctness of the data significantly affect the quality of the final CAD model as well as the machined workpiece. However, the point data measured with a typical coordinate measuring machine (CMM) have often been the data of the probe center rather than those of the object's surface, and this poses a great challenge in reverse engineering. This paper, thus, aims to resolve a practical problem in reverse engineering: what is the best way to compensate the measured data points with the value of probe radius? An approach to connecting corresponding points between every two adjacent measuring trajectories is proposed to formulate triangular meshes directly from the massive data points, so as to determine the normal vector of each point for probe-radius compensation. In the paper, the methodology and algorithms to implement the formulation of triangular meshes will be presented in detail with expository examples.

Rapid prototyping (RP) is an emerging, non-traditional fabrication method and has been recognized as a valid tool to shorten the lead-time from design to manufacture effectively. Most of the current RP systems adopt the triangular meshes of stereolithoraphy (STL) as a standard format for data input. Thus, the construction of triangular meshes directly affects the quality of RP parts and their subsequent processes. Traditionally, STL data are output from 3D CAD models built using commercial 3D CAD/CAM software packages. This study, however, differs from the traditional way in that it generates the STL data directly from scanned 3D data points, thus preventing various problems associated with 3D CAD modelling from a large quantity of data points. Specific tasks involved in this study include: (1) development of the methodology to convert massive data points into numerous, connected triangular meshes, (2) determination of unit normal vector for each triangular mesh facet, (3) output of triangular meshes with...

This paper proposes a new method to find the equations of transformation matrix for the rotation angles of the two rotational axes and the coordinates of the three linear axes of an orthogonal multi-axis milling machine. This approach provides intuitive physical meanings for rotation angles of multi-axis machines, which can be used to evaluate the accuracy of the conversion from CL data to NC data., {"references":["Y. Takeuchi, T. Watanabe, \"Generation of 5-Axis control collision-free\ntool path and post-processing for NC data,\" Annals of the ClRP. 41/1\n(1992) 539-542.","A. Rüegg, P. Gygax, \"A generalized kinematics model for three to five\naxis milling machines and their implementation in a NC,\" Annals of the\nClRP. 41/1 (1992) 547-550.","S. Sakamoto, I. Inasaki, \"Analysis of generating motion for five-axis\nmachining centers,\" The Japan Society of Mechanical Engineers. 59/561\n(1993) 1553-1559.","R. S. Lee and C. H. She, \"Developing a postprocessor for three types of\nfive-axis machine tools,\" International Journal of Advanced\nManufacturing Technology. 13 (1997) 658-665.","R. Md. Mahbubur, J. Heikkala, K. Lappalainen, J. A. Karjalainen,\n\"Positioning accuracy improvement in five axis milling by post\nprocessing,\" International Journal of Machine Tools and Manufacture.\n37/2 (1997) 223-236.","Y.H. Jung, D.W. Lee, J.S. Kim, H.S. Mok, \"NC post-processor for 5-axis\nmilling machine of table-rotating / tilting type,\" Journal of Materials\nProcessing Technology. 130-131 (2002) 641-646.","C. H. She, C. C. Chang, \"Development of a five-axis postprocessor\nsystem with a nutating head,\" Journal of Materials Processing\nTechnology. 187-188 (2007) 60-64.","C. H. She, Z. T. Huang, \"Postprocessor development of a five-axis\nmachine tool with nutating head and table configuration,\" International\nJournal of Advanced Manufacturing Technology. 38 (2008) 728-740.","M. Rahman, J. Heikkala, K. Lappalainen, \"Modeling, measurement and\nerror compensation of multi-axis machine tools. Part I: theory,\"\nInternational Journal of Machine Tools and Manufacture. 40 (2000)\n1535-1546.\n[10] L. M. Zheng, H. Lin, R. L. Gai, Postprocessor based on generalized\nkinematics model of five-axis machine tools,\" International Journal of\nComputer Integrated Manufacturing Systems. 16/5(2010) 1006-1011.\n[11] J. Andres, L. Gracia, J. Tornero, \"Inverse kinematics of a redundant\nmanipulator for cam integration. an industrial perspective of\nimplementation,\" Proceedings of the 2009 IEEE International\nConference on Mechatronics, Malaga, Spain, April 14-17, 2009.\n[12] F. Nagata, Y. Kusumoto and K. Watanabe, \"Intelligent machining system\nfor the artistic design of wooden paint rollers,\" Robotics and\nComputer-Integrated Manufacturing. 25 (2009) 680-688.\n[13] C. H. She, R. S. Lee, \"A postprocessor based on the kinematics model for\ngeneral five-axis machine tools,\" Journal of Manufacturing Processes.\n2/2 (2000) 131-141.\n[14] S. Ashmall, \"Post-processors for general purpose N.C. processor,\nProceedings of the Institution of Mechanical Engineers, 186/25 (1969)\n551-556.\n[15] C. H. She, C. C. Chang, \"Design of a generic five-axis postprocessor\nbased on generalized kinematics model of machine tool,\" International\nJournal of Machine Tools and Manufacture. 47 (2007) 537-545."]}

1. Use of ordered data points to fit a smooth surface. 2. Automatic selection of multiple cutting tools. 3. Generation of cutter-paths for rough machining. A cubic non-uniform B-spline (NUB) mathematical model is used for fitting measured data points into a smooth surface. For process planning based on the surface model, the selection and optimisation of cutting tools are based upon the criteria of maximum material removal and minimum tool change, while the generated NC cutter path ensures fast machining and the required surface quality.

Computer-aided process planning (CAPP), indispensable for industry automation, is credited the technical index for the aerospace industry. The objective of this research lies in developing a CAPP system to co-operate with fabrication of aircraft components, which are complicated and manifold in geometric shapes and manufacturing processes. Process charts are sheets output from a CAPP system and are typically used in the aerospace industry to assist machine operators in carrying out workshop machining tasks. Its contents include part name, part number, operation number, machining department, machining tool, machining operation, operation illustration, etc. Among these, operation illustration is the most tedious, yet important, data to make in illustrating the part machining processes. As a result, the CAPP system addressed in this paper possesses a special feature of integrating operation illustration with process database. In this paper, the development of a variant process planning system will first be addressed. The methodology for automatic generation of operation illustration, and its integration with process planning, is then discussed.