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Digital Thread for Manufacturing


The Digital Thread for Manufacturing project will deliver methods, protocols, and tools for developing, conformance testing, increasing user-awareness, and industrial adoption of product definition standards necessary for the digital transformation of manufacturing enterprises.  Smart manufacturing research at NIST has promoted a vision of fully-integrated, collaborative, manufacturing systems that respond in real time to meet changing demands and conditions in the factory, in the supply network, and in customer needs.  This vision is increasingly achievable by small-to-medium sized enterprises due to development of increasingly capable standards for conveying industrial data. 

Recent NIST pilot projects and proof-of-concept studies demonstrated that deployment of emerging model-based product definition standards reduces design-to-manufacturing cycle time and improves final part quality.  Further, much progress has been made at NIST since 2014 in advancing a suite of product-definition standards (i.e., STEP (ISO 10303), QIF (ISO 23953) and MTConnect) that enable the model-based enterprise.  However, there remain capability gaps in standards and tools that support the digital enterprise.  Standards gaps include hybrid geometry, globally-unique identifiers (GUIDs), semantic product and manufacturing information (PMI), and composite structures data representation alignment with composite structures practice standards.  Additionally, standards development cycles are too long to meet the changing industrial requirements.  There is a constant need to update reference data and reference software implementations that enable understanding, implementation, and adoption of standards.  Enterprises require tools for securing and building trust in data assets.  NIST has a proven track record of standards leadership and delivery of impactful research results.  This project will build on this success. 


Purpose and Goals

This project will provide research advances in product-definition standardization, conformance testing, and cybersecurity of data assets.

Digital thread standards capabilities and infrastructure - Smart connected manufacturing requires the effective communication of the product designs, through well-structured 3D product models, to the manufacturing and quality activities; the communication of manufacturing and quality considerations back to the design engineers; and the use of the 3D product models to specify form, fit, and function in the inspection systems and in-process measurement systems associated and communicate inspection and measurement results back to the design engineers. This is the goal of current industry efforts focused on actualizing 'digital twins', in which the heterogeneous data separated across engineering silos is resolved in a model-based paradigm. Achieving this level of integration requires resolving geometric and topological representational differences at the core of models created in all the different applications, by using technologies such as hybrid modeling, where critical PMI associativity relies on formalizing relationships between disparate solid modeling components. 

Digital thread standards implementation and testing - Conformance testing of manufacturing information against relevant standards remains a challenge due to time consuming manual processes for verification and validation.  EXPRESS-based STEP instance files can be automatically checked for syntax and structure conformance and XML-based QIF files can be checked that they are well-formed. However, information encoded semantically in those files is documented only in text- and diagram-based documents. The semantic information in instance files also needs to be checked for conformance. 

Development of correct implementations of STEP product and manufacturing information (PMI) has been enabled through publicly available reference NIST Test Case Models and corresponding STEP files annotated with PMI conforming to ASME Y14.5 and Y14.41. NIST Test Case Models were released in 2012 and again in 2014. These models are now in need of updating.  STEP AP242 edition 2 added new semantic PMI, translators were updated, and new versions of the native CAD systems were released. Additionally, changes to the test cases themselves are needed to reflect industry best practice.

Securing the digital thread - Proper curation of digital assets is critical to daily operations and requires permanent access and maintenance of trustworthy data. Corruption of that data can have catastrophic consequences on product development and affect viability of an enterprise. There is a need to protect the product data and its owner(s) by providing authorization, authentication, and traceability of trustworthy product data through the product lifecycle. Currently, knowing who can use data, how the data can be used, and who did what to the data is mainly captured in contracts and manual paper-based tracking methods. Industry needs a faster, more secure, and sustainable way to record, embed, or link authentication, authorization, and traceability information to the product data

Technical Approach

Digital thread standards capabilities and infrastructure - NIST will continue its support of key leadership roles in ISO TC 184/SC 4 Industrial Data: including a standards project manager and editor, the STEP Product Modeling and Resources Working Group Convener, and the Geometric and Topological Representation Team Lead. NIST will support an integrated development environment to automate the publication of STEP resource parts. Development of the fourth edition of ISO 10303-242 (AP242e4) started in FY22. NIST will serve on the AP242e4 Steering Committee, support research to underpin new methods and models for the use of GUIDs, hybrid geometric modeling and overall coherence of ISO 10303-42 Geometry and Topology, models for new semantic PMI, and harmonization of the ISO 10303 composite structures data representations with the ASME composite structures practice standards.

  • Standards leadership 
  • STEP Resource Library publication system 
  • New capabilities for AP242 edition 4
    • GUIDs 
    • Hybrid geometric modeling 
    • PMI 
    • Composite structures harmonization 

Digital thread standards implementation and testing - Research related to conformance testing is rooted in the NIST PMI Validation and Conformance Testing Project and will focus on semantic representations of product and manufacturing information (PMI) in product definitions standards for smart manufacturing and how they are tested. PMI is used to communicate the allowable tolerances to manufacturing and inspection systems.  NIST will add capabilities to the NIST STEP File Analyzer and Viewer software to support new PMI as it is tested by the CAx Interoperability Forum and build support for viewing assemblies and bills of material. 

  • Develop enhancements to the STEP File Analyzer and Viewer based on user requirements, implementor forum input, and new features of the standards.
  • Develop new set of NIST PMI test case models
  • Co-lead interoperability forum to test software implementations of STEP.  

Securing the digital threadData tampering—either intentional (i.e., cyberattacks) or unintentional (e.g., human or system error)—can lead to serious consequences in the physical world, such as structurally weaker or functionally different parts. The complexity of today’s goods and the distributed nature of supply chains involves a significant number of heterogeneous information systems operating on both business and engineering data. These systems are integrated to consume data from each other in a high-volume and fast-paced environment where tampered data can be quickly propagated across many systems and organizations. This project will explore leveraging open standards and model-based integration specifications to quickly investigate and isolate infected systems.

  • Implement a web-based solution for investigating and evaluating data tampering
  • Develop cybersecurity metrics, aligned with with NIST SP 800-series cybersecurity guidance, to evaluate the risk of exposure to data tampering

This project will also replace the Digital Manufacturing Certificate Toolkit with a web app that simplifies the process of building digital trust using proven security standards. 

  • Develop the NIST EasyTrust platform, including a configuration manager, a web server, and a client web application
  • Validate the platform by identifying new stakeholders, managing their use cases, and meeting their technical constraints


PMI Test Cases

Assess and revise existing, and/or create new NIST Test Cases for ISO 10303 (aka STEP), incorporating new geometric dimensioning and tolerancing (GD&T) capabilities. Ensure compliance with ASME Y14 standards for GD&T. The NIST Test Case Models (2012, 2014) were a key factor in the correct implementation of STEP in commercial software systems (continues into FY23).

Assemblies in SFA

Implement support for assembly structure in the NIST STEP File Analyzer and Viewer (FY22).

Data Traceability Web Framework

Develop a web-based application for investigating and evaluating data tampering using open standards and model-based integration specifications that are aligned with NIST SP 800-series cybersecurity guidance. (FY22).


Develop methods and models that correlate globally unique identifiers with product characteristics in globally unique identifiers with product characteristics in CAD models and derived ISO 10303-242 files to enable tracing of related manufacturing requirements back to the originating system (FY22).

Created April 19, 2022, Updated June 16, 2022