Model-based Definition Research Articles

Promoting Model-based Definition to Establish a Complete Product Definition.

The manufacturing industry is evolving and starting to use 3D models as the central knowledge artifact for product data and product definition, or what is known as Model-based Definition (MBD). The Model-based Enterprise (MBE) uses MBD as a way to transition away from using traditional paper-based drawings and documentation. As MBD grows in popularity, it is imperative to understand what information is needed in the transition from drawings to models so that models represent all the relevant information needed for processes to continue efficiently. Finding this information can help define what data is common amongst different models in different stages of the lifecycle, which could help establish a Common Information Model. The Common Information Model is a source that contains common information from domain specific elements amongst different aspects of the lifecycle. To help establish this Common Information Model, information about how models are used in industry within different workflows needs to be understood. To retrieve this information, a survey mechanism was administered to industry professionals from various sectors. Based on the results of the survey a Common Information Model could not be established. However, the results gave great insight that will help in further investigation of the Common Information Model.

Integrating modeling mechanism for three-dimensional casting process model based on MBD

The objective of this research is to propose an integrating modeling mechanism for three-dimensional casting process model (TDCPM) based on model-based definition (MBD). Firstly, the structure of the three-dimensional casting process model is put forward, and the TDCPM is comprised of three components: (1) process geometry model, (2) process information, and (3) process dimension information, building the relationship between the three components and give the planning procedure. Secondly, research the construction process of the casting part, gating system, and risering system; provide data structure, analysis method, and rebuilding mechanism of process dimension information; and introduce the casting process parameter and process planning history mechanism for TDCPM. Finally, a casting process planning system prototype is developed based on the proposed modeling mechanism.

Robust Improper Maximum Likelihood: Tuning, Computation, and a Comparison With Other Methods for Robust Gaussian Clustering

ABSTRACTThe two main topics of this article are the introduction of the “optimally tuned robust improper maximum likelihood estimator” (OTRIMLE) for robust clustering based on the multivariate Gaussian model for clusters, and a comprehensive simulation study comparing the OTRIMLE to maximum likelihood in Gaussian mixtures with and without noise component, mixtures of t-distributions, and the TCLUST approach for trimmed clustering. The OTRIMLE uses an improper constant density for modeling outliers and noise. This can be chosen optimally so that the nonnoise part of the data looks as close to a Gaussian mixture as possible. Some deviation from Gaussianity can be traded in for lowering the estimated noise proportion. Covariance matrix constraints and computation of the OTRIMLE are also treated. In the simulation study, all methods are confronted with setups in which their model assumptions are not exactly fulfilled, and to evaluate the experiments in a standardized way by misclassification rates, a new model-based definition of “true clusters” is introduced that deviates from the usual identification of mixture components with clusters. In the study, every method turns out to be superior for one or more setups, but the OTRIMLE achieves the most satisfactory overall performance. The methods are also applied to two real datasets, one without and one with known “true” clusters. Supplementary materials for this article are available online.

Gaps Analysis of Integrating Product Design, Manufacturing, and Quality Data in The Supply Chain Using Model-Based Definition.

Advances in information technology triggered a digital revolution that holds promise of reduced costs, improved productivity, and higher quality. To ride this wave of innovation, manufacturing enterprises are changing how product definitions are communicated - from paper to models. To achieve industry's vision of the Model-Based Enterprise (MBE), the MBE strategy must include model-based data interoperability from design to manufacturing and quality in the supply chain. The Model-Based Definition (MBD) is created by the original equipment manufacturer (OEM) using Computer-Aided Design (CAD) tools. This information is then shared with the supplier so that they can manufacture and inspect the physical parts. Today, suppliers predominantly use Computer-Aided Manufacturing (CAM) and Coordinate Measuring Machine (CMM) models for these tasks. Traditionally, the OEM has provided design data to the supplier in the form of two-dimensional (2D) drawings, but may also include a three-dimensional (3D)-shape-geometry model, often in a standards-based format such as ISO 10303-203:2011 (STEP AP203). The supplier then creates the respective CAM and CMM models and machine programs to produce and inspect the parts. In the MBE vision for model-based data exchange, the CAD model must include product-and-manufacturing information (PMI) in addition to the shape geometry. Today's CAD tools can generate models with embedded PMI. And, with the emergence of STEP AP242, a standards-based model with embedded PMI can now be shared downstream. The on-going research detailed in this paper seeks to investigate three concepts. First, that the ability to utilize a STEP AP242 model with embedded PMI for CAD-to-CAM and CAD-to-CMM data exchange is possible and valuable to the overall goal of a more efficient process. Second, the research identifies gaps in tools, standards, and processes that inhibit industry's ability to cost-effectively achieve model-based-data interoperability in the pursuit of the MBE vision. Finally, it also seeks to explore the interaction between CAD and CMM processes and determine if the concept of feedback from CAM and CMM back to CAD is feasible. The main goal of our study is to test the hypothesis that model-based-data interoperability from CAD-to-CAM and CAD-to-CMM is feasible through standards-based integration. This paper presents several barriers to model-based-data interoperability. Overall, the project team demonstrated the exchange of product definition data between CAD, CAM, and CMM systems using standards-based methods. While gaps in standards coverage were identified, the gaps should not stop industry's progress toward MBE. The results of our study provide evidence in support of an open-standards method to model-based-data interoperability, which would provide maximum value and impact to industry.

Testing the Digital Thread in Support of Model-Based Manufacturing and Inspection.

A number of manufacturing companies have reported anecdotal evidence describing the benefits of Model-Based Enterprise (MBE). Based on this evidence, major players in industry have embraced a vision to deploy MBE. In our view, the best chance of realizing this vision is the creation of a single "digital thread." Under MBE, there exists a Model-Based Definition (MBD), created by the Engineering function, that downstream functions reuse to complete Model-Based Manufacturing and Model-Based Inspection activities. The ensemble of data that enables the combination of model-based definition, manufacturing, and inspection defines this digital thread. Such a digital thread would enable real-time design and analysis, collaborative process-flow development, automated artifact creation, and full-process traceability in a seamless real-time collaborative development among project participants. This paper documents the strengths and weaknesses in the current, industry strategies for implementing MBE. It also identifies gaps in the transition and/or exchange of data between various manufacturing processes. Lastly, this paper presents measured results from a study of model-based processes compared to drawing-based processes and provides evidence to support the anecdotal evidence and vision made by industry.

Implementations of Model Based Definition and Product Lifecycle Management Technologies: a Case Study in Chinese Aeronautical Industry

The paper describes and analyzes the Model Based Definition (MBD) and Product Lifecycle Management (PLM) technologies and their related Computer-Aided X applications in order to enable the implementation of an integrated design and manufacturing system in Chinese aeronautical industry. Using the full three-dimensional technology allows the MBD specification of geometry, features and attributes for mechanical parts. It also supports an integrated design method for specifying MBD models of these parts. Considering the manufacturing specifications based on MBD, the feature machining and Coordinate Measuring Machine (CMM) control technologies are used for intelligent manufacturing of parts. Machining and quality inspection programs are automatically generated including the associated MBD process and quality models. Finally, the integrated design and manufacturing system based on MBD and PLM technologies is applied on the case study of an engine fan blade in order to assess the proposed method.

A Publishing Method of Lightweight Three-Dimensional Assembly Instruction for Complex Products

In order to accurately guide on-site workers to quickly accomplish the assembly job of complex products, and reduce the deployment cost of assembly instruction, we propose a publishing method of lightweight 3D assembly instruction for complex products. In this paper, the key frames of assembly motion and the 3D technical annotations in the lightweight model are mapped to the time-based assembly process. Then, the annotated lightweight model and assembly process information are integrated and published into a single 3D assembly instruction document. An assembly instruction publishing example of satellite antenna feed component shows that the lightweight 3D assembly instruction is well instructive and affordable because it provides the interactive simulation of assembly process and time-based display of assembly technical annotations without using expensive computer-aided design (CAD) systems, graphics workstations, or virtual reality equipments. This method gives a full play to the advantages of model-based definition technology and lightweight model, and fills the gap between the process planning and the instruction publishing in the 3D virtual manufacturing environment.

An effective subpart retrieval approach of 3D CAD models for manufacturing process reuse

As a vast number of 3D CAD models associated with manufacturing processes are generated each year, retrieval of 3D CAD models for achieving manufacturing process reuse is becoming an effective strategy for engineers to generate the process plan with less time and lower cost. However, there has been little research on how to find the similar subparts for manufacturing process reuse. In this paper, a novel subpart retrieval approach of 3D CAD models for manufacturing process reuse is presented. First, coupled machining feature cluster (CMFC) is introduced to represent the 3D CAD model into structured MBD (model-based definition) model taking machining features as the carrier of manufacturing semantics. Then, part layer code and CMFC content code for accelerating subpart retrieval are given to filter out unmatched subparts efficiently. Moreover, a multilevel feature descriptor capturing different levels of information for manufacturing process planning is designed to establish the machining feature similarity assessment model. Finally, the machining feature coupled graph (MFCG) based subpart matching algorithm is presented to calculate the similarity between matched subparts. A prototype system has been developed to verify the effectiveness of the proposed approach.

Research of the Technology and Application of Process Digital Mock-Up for Spacecraft Assembly Based on the MBD

After representing the situation of the spacecraft assembly and the concept of Model Based Definition (MBD), the paper describes the method and principle of Assembly Digital Mock-up (ADMU), which achieved the transition of Engineering Bill of Material (EBOM) to Process Bill of Material (PBOM). With reconstructing EBOM and fulfilling structured Product Attribute, the paper gains the ADMU, which is the data source of spacecraft assembly process design based on 3D models.

Multi-level structuralized model-based definition model based on machining features for manufacturing reuse of mechanical parts

Model-based definition (MBD) is a new strategy of managing engineering and business processes using 3D models as complete information sources. However, due to lack of feature-based data model representation approach, current MBD models cannot be applied well in manufacturing domain. In this paper, a new multi-level structuralized MBD model based on machining features for manufacturing reuse is presented to capture the abstract information, detailed feature interaction information, and machining semantics information involved. Firstly, the machining features are recognized from an MBD model, which are taken as the machining semantics carrier. Then, the coupled machining feature cluster is introduced to construct the greater granularity’s independent structural element than machining feature, which describes the feature interactions. Finally, the MBD model is structured based on machining features and coupled machining feature clusters in a hierarchical way. In the experiments, some aircraft structural parts are utilized to verify our approach for manufacturing reuse, and the experimental results are analyzed at length to show the application effectiveness of the multi-level structuralized MBD model.

Quality Evaluation for Model Based Definition of Aerospace Products

With the rapid development of computer aided technology, the application of model based definition (MBD) in the research and development (R&D) processes of aerospace products become more and more widespread. The quality of MBD refers to its ability to meet the requirements of the downstream processes like subsequent design, manufacture, simulation, and inspection etc. Based on MBD’s quality characteristics, such as modeling and simulation quality, design process quality, geometry and topology quality, data quality and data exchange quality, this paper constructs a quality model for aerospace digital products and proposes both qualitative and quantitative quality evaluation methods for MBD of aerospace products.

3D Machining Process Planning Based on Machining Feature Recognition Technique

In the model-based definition (MBD) scheme, activities of process planning need to be carried out in 3D environment. To realize the 3D computer-aided process planning (3D CAPP), the design solid model needs to be transferred into a representation as manufacturing features, features’ process requirement and product manufacturing information (PMI), and then the generative process planning techniques can be realized by inferring machining operations based machining feature knowledge base. A machining feature-based 3D computer-aided process planning approach is proposed for machining part. Design model is transferred into boundary representation (B-Rep). According to a machining features classification scheme, hybrid machining feature recognition technique is introduced. A part process information model is generated including machining features, feature relationship, feature’s process chain. For each recognized machining feature, a feature’s process chain is inferred from feature knowledge base, based on feature type, process requirements, dimension and tolerances, and the enterprise manufacturing resources. Process intermediate models corresponding to each process operation are generated automatically by applying geometry local modification operations. The complete process plan is generated and documented with detailed operation information and 3D process intermediate models. A 3D CAPP tool is developed on ACIS/HOOPS, with industrial cases to demonstrate the feasibility and applicability of proposed method.

A Feature-Based Automatic Dimension Marking Method for In-Process Models

To reduce the workload for marking the dimensions of in-process models, a method of dimension marking based on manufacturing features for in-process model is proposed. Firstly, the dimension information is extracted from model based definition (MBD) models; secondly, the feature dimension chains are constructed according to the feature location dimension and the process data, when the process data and design data are not coincided with each other; thirdly, the process dimension tolerances are calculated by using the increasing links and the decreasing links of the MBD. In experimental section, an example was given to illustrate the validity and effectiveness of the proposed method.

Digital Three-Dimensional Labeling System of Product Design Information Based on MBD

MBD (Model Based Definition) technology is the development trend of digital design and manufacture. Design information includes geometric elements, annotations and process attributes. In the paper, the focus is concentrated on digital three-dimensional (3D) labeling of annotations. The 3D labeling system of product design information is seamlessly integrated with NX platform to define digital information of a 3D product model. The Key technologies of the 3D labeling system realization on NX platform mainly includes transformation of space coordinates, reference plane construction based on solid modeling and 3D dimensioning. NX internal program mode is adopted where the developed program is compiled and linked to generate the dll file whose codes are small and whose connection speed is fast. Integrated digital definition of a 3D model shortens product development cycle and improves product design and manufacturing efficiency.

An Obstacle Avoidance Algorithm for Path Planning Based on Inspection MBD Model

Aiming at measuring path planning, based on inspection MBD (Model Based Definition) models of the measured parts, size and position information of the parts features are generated. Global coordinate equations of the features are established. In measuring process, probe heads should move along the outer normal vector, and the path should be the shortest. Under these constraint condictons, the obstacle avoidance path are created between the probe head starting points and the inspected features origin points. Finally, an example is given to verify the algorithm, which offers a base for the whole path planning considering the change of the probe heads and their direction.

Revisiting the ‘Low BirthWeight paradox’ using a model-based definition

IntroductionImmigrant mothers in Spain have a lower risk of delivering Low BirthWeight (LBW) babies in comparison to Spaniards (LBW paradox). This study aimed at revisiting this finding by applying a model-based threshold as an alternative to the conventional definition of LBW. MethodsVital information data from Madrid was used (2005–2006). LBW was defined in two ways (less than 2500g and Wilcox's proposal). Logistic and linear regression models were run. ResultsAccording to common definition of LBW (less than 2500g) there is evidence to support the LBW paradox in Spain. Nevertheless, when an alternative model-based definition of LBW is used, the paradox is only clearly present in mothers from the rest of Southern America, suggesting a possible methodological bias effect. ConclusionIn the future, any examination of the existence of the LBW paradox should incorporate model-based definitions of LBW in order to avoid methodological bias.

A design method for three-dimensional maintenance, repair and overhaul job card of complex products

Aiming to improve the feasibility of maintenance, repair and overhaul (MRO) planning, the accuracy of MRO description and the clarity of on-site guidance for complex products MRO job card, a design method for complex products three-dimensional (3D) MRO job card based on product 3D model and using the model based definition (MBD) technology was proposed. This method applies position–posture calculation of initial disassembly based on assembly constraints to realize the visual disassembly planning for complex products in 3D environment, uses dynamic viewpoint navigation method to implement the display of disassembly and assembly simulation process of parts conforming to the observation habit of human, adopts multi-view 3D annotation method to implement the separation showing for technical requirements from different MRO disciplines and operation tasks, and finally, transforms the MRO order information into 3D portable job card file based on lightweight model and releases it to MRO worksite. The aircraft right wing maintenance instance shows that this method can implement the intuitive, accurate and non-ambiguous MRO process description, improve the rationality of MRO planning, and increase the efficiency and quality of complex products MRO.

Digital Design and Implementation Based on MBD

Model based definition (MBD) is the new trend of CAD technology development. Concerning with current situation of manufacturing industry of our country, the solution of model based digital design and assembling is presented and key issues of its implementation. It enhances design efficiency and product manufacturability.

Exploration of the Modeling Process of Assembly Based on MBD and Pro/ENGINEER

The 3D (three dimensional) assembly model should provide all of the product information in order to realize pure 3D modeling in PLM(Product Lifecycle Management). This paper briefly introduces the development of MBD (Model-based Definition) at first, and then the overall information needed in 2D (two dimensional) assembly drawing is presented. At last, the overall needed information (dimensions, technical requirement, BOM(Bill of Materials)) is acted upon 3D assembly model successfully through the use of functions, for example, annotation, layer and view in Pro/ENGINEER.

Exploration of Non-Revolved Parts Modeling Based on MBD and Pro/ENGINEER

A great change in mechanical industry has occurred after several successful practices using MBD (Model Based Definition) of The Boeing Company. It is an inevitable trend from two-dimensional product definition to three-dimensional product definition in mechanical industry. Several standards for MBD have emerged around the world. This paper explores the non-revolved parts modeling methods based on MBD and Pro/ENGINEER, presents several key steps about full-annotated model per MBD and then makes a conclusion. Following these methods we successfully build a typical non-revolved model which conforms to MBD standards correctly and efficiently.