Product Engineering

Program Manager: Ram Sriram
Total FTE: 9

Program Goal:

Establish a semantically-based, validated, product representation scheme as a standard that supports the seamless interoperability among current and next generation computer-aided design systems (CAD) and between CAD systems and other systems that generate and use product data, thus helping the manufacturing industry achieve a 10 % reduction in interoperability costs and a tenfold improvement in design exploration capability.

Customer Needs:

According to a Daratech report, currently CAD/computer aided manufacturing (CAM)/computer aided engineering (CAE) constitute an approximately a $6.5 billion per year industry. With new emerging areas, such as immersive CAD and knowledge-based CAD, this is likely to increase considerably in the next decade. One major problem with the emergence of various heterogeneous CAD systems is the lack of interoperability among these systems. A 1999 study by RTI International (http://www.rti.org) estimated that imperfect interoperability imposes costs of at least $1 billion per year on the U.S. automotive supply chain alone; other industries may have similar costs associated with lack of interoperability among CAD/CAE/CAM applications. This has significant implications for the costs at all design stages, and has an enormous impact on the overall product cost, as decisions made during the design stage determine 70 % of the product's cost over its life.

To assess the importance of various CAD/CAE technologies to industry, as well as to identify specific interoperability needs, several workshops have been sponsored by NIST: Standard for the Exchange of Product Model data (STEP)-based Solid Interchange Format Workshop (November 1996): NIST Design Repository Workshop (November, 1996): Network-Centric CAD: A Research Planning Workshop (December, 1996): Tools and Technologies for Distributed and Collaborative Design (August, 1997): Assembly Level Tolerancing: Standards and Implementation Issues Workshop (April 1997): Knowledge-based Systems Interoperability Workshop (November, 1997): Intelligent and Distributed CAD Workshop (July, 1998): Design Manufacturing Integration Workshop (November 1998): and Virtual Assembly Technology Meeting (March 1999). Each of these workshops was attended by dozens of practitioners and researchers from large and small businesses, government, and academia, representing the country's leading engineering organizations, software vendors, and academic institutions. These workshops clearly underscored the need for interoperability standards and knowledge representation schemes, as articulated by the Product Engineering Program.

In addition to the above workshops, a number of other supporting documents have been researched that identify critical industry needs in this area. These include: Manufacturing Infrastructure: Enabling the Nation's Manufacturing Capacity (Committee on Technological Innovation, National Science and Technology Council): Collaborative Virtual Prototyping Sector Study (study sponsored by the U.S. Navy, study performed by the North American Technology and Industrial Base Organization): Integrated Manufacturing Technology Roadmap (government-funded technology roadmap): Information Technology for Manufacturing: A Research Agenda (from the Committee to Study Information Technology and Manufacturing, National Research Council, National Academy Press, 1995): General Electric (GE) Pilot Project Case Study Report (GE case study sponsored by Defense Advanced Research Projects Agency (DARPA)): Visionary Manufacturing Challenges for 2020 (Committee on Visionary Manufacturing Challenges, National Research Council, National Academy Press, 1998): Advanced Engineering Environments (Committee on Advanced Engineering Environments, Aeronautics and Space Engineering Board, National Research Council, National Academy Press 1999, 2000), and others.

Technical Approach:

The Product Engineering program focuses on the key issues that are emerging from the new collaborative product development paradigm. Specifically, the primary needs for the next generation of CAD/CAM/CAE software systems are interoperability among software tools, collaboration among distributed designers and design teams, integration of data and knowledge across the product development cycle (from design to analysis to manufacturing and beyond), as well as knowledge capture, exchange and reuse. This program’s activities and efforts range from specification and standards development to technology development and prototype implementation. The program is intended to provide the foundation that will support the creation of next-generation product development tools, thereby increasing the efficiency, effectiveness, capability and productivity of U. S. industry.

STEP (ISO 10303, informally known as STandard for the Exchange of Product model data) is capable of successfully transferring product shape models in terms of their geometry and topology. However, modern CAD systems generate models containing additional information concerned with parametric representation, constraints and features. This permits a shape model to be edited or optimized according to the designer's original notions. It is highly desirable that STEP be extended to capture and transmit this additional information, to make it easier to edit models following a transfer. The Parametrics project is currently working towards this goal, with the aim of saving the time currently spent in trying to regenerate information that was present in the transmitted model but lost in translation into the STEP format. The result will be improved efficiency in the product development cycle.

One of the gaps in current CAD tools is a lack of standardized representations for some types of assembly data, such as inter-part relationships, mating features, and others. Such representations will enable more efficient and cost-effective integration of assembly analysis tools, and more accurate translations of data. It is expected that work on assembly modeling and representation will provide input to the incorporation of assembly information content into STEP. Proceeding in conjunction with this work is an effort on the development of methods and best practices for tolerance analysis and synthesis. The aim of this work is to advance the use of tolerancing information to the earliest possible stages of design, in contrast to the traditional approach of performing tolerance synthesis after design. This, in turn, requires effective representation of tolerancing information during various stages of design such as during assembly modeling.

One of the serious current interoperability gaps is between CAD design tools and CAE analysis tools. The design-analysis integration project has pragmatic and conceptual components. On the pragmatic side, we are collaborating with the TIDE (Technology Insertion Demonstration Experiment) program of the Software Engineering Institute (SEI) at Carnegie Mellon University in improving CAD-CAE interoperability for small defense contractors. Our task is to provide guidance in the implementation of a pilot technology program and to extract generalizations from the TIDE results. On the conceptual side, we are defining a data architecture consisting of a common master model and a number of discipline-specific aspect models, treating the spatial (CAD) model as just another aspect model in parallel with discipline-specific analysis models (e.g., those supporting strength, thermal, and flow analysis). A number of organizing principles for the master model and implementation principles for a potential system are being investigated.

Layered Manufacturing (LM), also known as solid freeform fabrication (SFF) or rapid prototyping (RP), is an additive manufacturing process in which the objects are constructed layer by layer. Considerable progress has been made in the last decade and it is now possible to produce multi-material objects, with functionally graded material, in LM machines. Where as the LM technology is progressing ahead, the mechanism of transferring the data from a CAD system to LM system has remained unchanged. The de-facto industry standard, Stereolithography (STL) file format, whose format consists of a mesh of connected three-dimensional triangles that represent the part shape. One of the major deficiencies in the STL format is the inability to represent heterogeneous material. In this research we propose to work towards the development of a representation scheme that would address this and other deficiencies in STL and enable advanced capabilities from next-generation manufacturing systems. Our approach would build upon several primitives available in STEP ISO 10303. In addition, we will strive toward the development of a theoretical framework for dealing with the representation of heterogeneous material.

In the area of knowledge representation for next generation CAD, one project is working toward the development of an information modeling framework to support the creation of design repositories, the next generation of design databases that would facilitate knowledge-aided e-commerce. This project is driven by industry needs for technology to support the increasing role of knowledge-based design, including the representation, capture, sharing, and reuse of corporate design knowledge. A second project deals with the development of a core product representation---called the Core Product Model (CPM)---and semantic foundations that support the long term objective of self integrating systems.

Program Objectives and Technical Outputs:

Objective 1: By FY2003, develop STEP resource on parameterization and geometric constraints to Draft International Standard (DIS) level. (Parametrics Exchange)

Technical Output
FY 2003: Parametrics Exchange: DIS version of ISO 10303 Part 108 document.

Objective 2: By FY2003, develop case studies to demonstrate the proposed assembly and tolerance information model, with specific focus on tolerance analysis and synthesis. (Assembly and Tolerance Representation)

Technical Output
FY 2003: Assembly and Tolerance Representation: Proposed model included in proposed ISO 10303 Part 44 and Part 109.

Objective 3: By FY2003, develop and publish an information-modeling framework based on a semantically rich master product model for the support of all design and analysis activities throughout the design lifecycle of an artifact. (Design-Analysis Integration)

Technical Output
FY 2003: Design-Analysis Integration: Report describing information modeling framework with potential organizing and implementation principles.

Objective 4: By FY 2003, perform computational experiments to study feasibility of the material-solid modeling using distance fields in common engineering situations. (Heterogeneous Material Representation)

Technical Output
FY 2003: Report detailing the ingredients of the proposed representation scheme and analysis of how these maybe incorporated within ISO standards.

Objective 5: By FY2003, develop formal computer interpretable representations for archiving and retrieving information flow in design. (Knowledge Representation for Next Generation CAD)

Technical Output
FY 2003: Document describing an object-based representation that can define the intended behavior of devices.

Objective 6: By FY2004, work toward standardization of the UML models for assembly and tolerance representation with ISO 10303 SC4/WG12 and work with ASME Y14.5.M-200X on proposed Revision of ASME Y14.5M-1994 (R 1999) to include assembly level tolerance standards. (Assembly and Tolerance Representation)

Technical Output
FY2004: Report describing the use of the proposed assembly and tolerance representation in the harmonization of ASME and ISO efforts.

Objective 7: By FY2004, develop and publish an elaborated version of an information modeling framework based on further research, feedback from industry and standardization organizations. (Design-Analysis Integration)

Technical Output
FY2004: Report and technical presentations of elaborated framework.

Objective 8: By FY2004, propose specific data structures and algorithms for incorporating the new technology within existing CAD systems. (Heterogeneous Material Representation)

Technical Output
FY2004: Prototype system demonstrating the developed capabilities and a report summarizing the developed techniques and algorithms.

Objective 9: By FY2004, develop a logic-based representation scheme that can be used for verifying intended behaviors. (Knowledge Representation for Next Generation CAD)

Technical Output
FY2004: Report describing the logic-based approach and a prototype demonstrating the proposed approach.

Objective 10: By FY2005, formalize the proposed assembly and tolerance representations into an ontologoical framework to achieve semantic interoperability. (Assembly and Tolerance Representation)

Technical Output
FY2005: Publications describing the ontological framework and appropriate ISO/ASME documents.

Objective 11: By FY2005, demonstrate non-trivial applications of the new proposed representation and technology in the context of design and/or manufacturing applications, including engineering analysis and/or planning. (Heterogeneous Material Representation)

Technical Output
FY2005: Report summarizing capabilities of the developed technology, future directions, and open issues.

Objective 12: By FY2005, diffuse the proposed knowledge representation scheme to the industry and various standards organizations, including demonstration of knowledge-level interoperability. (Knowledge Representation for Next Generation CAD)

Technical Output
FY2005: Prototype demonstrating knowledge-level interoperability between two CAD systems and associated publications.

Objective 13: By FY2005, develop a five-year plan for future work in the Product Engineering Program. Roadmap Document

Technical Output
FY2005: A document describing the roadmap for Product Engineering Research.

Anticipated Impacts:

The ultimate technical benefits of the Product Engineering Program are improved infrastructures for using and exchanging design knowledge, and for the seamless integration of design and production information across time, space and engineering domains. These benefits will translate to broad-based economic benefits through accelerated product development, reduced direct design costs, and improved product quality. For example:

1. Enhanced knowledge-aided electronic commerce for supporting intelligent and distributed design. Access to distributed design databases and seamless interoperability among CAD systems would result in an efficient electronic commerce framework.
2. Increased competitiveness of U.S. industry by reducing design and production costs as well as product development time. Specific targets include: reduction in direct design costs of 10 % to 30 %, reduction of time-to-market of 25 % to 75 %, and reduction of defect rates and engineering change requests of 23 % to 70 %. The range in values reflects the variances from one industry to another on the realistic degree of improvement.
3. Increased capture and linkage of design information across various stages of the product life cycle. Benefits will include improved reuse of design information across product families, and more rapid redesign efforts. In addition to reducing development time, improved feedback of knowledge into subsequent design processes will increase quality and reduce warranty and repair costs later on.
4. Better interoperability through use of formal semantics. Traditionally, interoperability is done without explicit exchange of semantic information by agreeing on semantics prior to definitions of standards and exchange mechanisms. The addition of ontological information-to-information exchange, enabling semantic interoperability, is a key stage along the path toward self-describing and ultimately self-integrating systems.

Accomplishments of the Past Year:

New resource, so far unnumbered (Procedural and hybrid representation) – submitted for a joint New Work Item proposal and CD ballot. This resource will provide basic mechanisms for construction history modeling.

Assembly and Tolerance Representation
A draft version of an assembly/tolerance model using UML was completed.

ISO’s proposed assembly representation (ISO Part 109) and NIST assembly model were thoroughly discussed at a recent ISO meeting and subsequently at Nihon Unisys Headquarters with the Japanese National Committee.

Participated in the VATC (Virtual Assembly Technology Consortium) meeting. VATC is an industry-university-government consortium that aims to demonstrate immersive CAD applications and to develop open standards for integrating traditional CAD and immersive CAD systems.

Sudarsan Rachuri gave the keynote address at ASPE (American Society of Precision Engineers) Summer Topical Meeting on Tolerance Modeling and Analysis (Charlotte, NC, July 15-16, 2002). He gave an invited presentation entitled “Information models for Design Tolerancing of Electro mechanical Assemblies.”

Design-Analysis Integration
Developed a hierarchical, multi-aspect information architecture, with a Master Model containing shared information and functional models acting as views on the Master Model.

Wrote several technical reports for the TIDE program of the Software Engineering Institute at Carnegie Mellon University.

Knowledge Representation for Next Generation CAD
Simon Szykman gave the Keynote Address on the NIST Design Repository Project, at an organized event on the topic of knowledge management (“Creating Value from Knowledge Assets”) sponsored by the NASA Goddard Space Flight Center's Goddard Library.

Completed the design rationale extensions to the NIST Core Product Model.

Extended distributed web-based architecture implementation.

Expanded design repository database and interfaces to allow for inclusion of catalog design data. (System was previously focused on modeling of in-house-designed artifacts and did not allow for easy inclusion of catalog components.)

Developed tools to aid in creation and population of organized component catalogs for design repositories

2002 Program Workshops:

April 2002: Role of Empirical Studies in Understanding and Supporting Engineering Design

DPG co-sponsored a workshop entitled Role of Empirical Studies in Understanding and Supporting Engineering Design that was held at NIST on April 4th and 5th. The goal of the workshop was to bring academics and industry people together to create a better understanding of industrial design practice and the design of tools to support that practice. As a nascent field, other goals of the workshop including creation of self awareness amongst participants to create a community, getting an understanding of questions, methods and tools used by the researchers and to develop a classification of their use and to propose methods to improve the appreciation of this work in academia, in the classroom and in industry. There were 23 participants including personnel from NIST, from 5 European countries and 4 US universities and 3 industrial participants from the U.S. There were totally four paper sessions and two discussion sessions. The sessions were; a) Case studies b) Three perspectives on empirical studies from Aachen, c) insight from case studies and d) reflections from case studies.

July 2002: Interagency Working Group for Engineering Design Meeting

Ram D. Sriram hosted a meeting for the Interagency Working Group for Engineering Design at NIST on July 15th and 16th. Participants from NASA, NRO, JPL, NSF, TASC, and representatives from Triodyne, Lockheed Martin, and Boeing Company attended this meeting. The industry speakers presented their work and needs for design research. This was followed by a series of presentations from NIST staff and a few presentations from participants from other agencies, including NSF, NRO, and JPL. Richard Neal from IMTI facilitated the discussions. A report detailing a roadmap for design research will be prepared shortly.

Standards Participation:

American Society of Mechanical Engineers (ASME) Y14.5 Dimensioning and Tolerancing (GD&T)
Participate in committee activities.

American Society of Mechanical Engineers (ASME) Y14.5.1 Mathematical Definition of Dimensioning and Tolerancing Principles
Participate in committee activities.

ISO TC184/SC4/WG12 Industrial Data, Common Resources
Provide leadership for the Parametrics Group, which is developing Part 108 of STEP (Parameterization and constraints for explicit geometric product models) and a new approach to product shape modeling in terms of its constructional history.

OMG Manufacturing Domain Task Force (Mfg DTF)
Participate in OMG's Manufacturing Domain Task Force. This organization is responsible for setting the overarching strategy for the working groups that comprise the task force. Current activity involves participation in the development of CAD interface specifications.

ISO TC 184/SC4 Parametrics Project and Assembly Representation
Participate and provide leadership for ISO activities related to assembly and tolerance representation. SC4 is developing standards, which provide capabilities to describe and manage product data throughout the life of the product. It is expected that the proposed work on assembly modeling and assembly representation will provide useful inputs to the development of the proposed STEP Part 109 assembly standard and will enhance the assembly information content in STEP AP 203 (Configuration controlled design).

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Date Create: December 9, 2002
Last Modified: December 9, 2002