Digital Thread

White Paper by Bernhard Rumpe, NN, Software Engineering, RWTH Aachen, Release-Date

Digital Thread is a term often used in the context of Digital Twins. Some people think that the digital thread is the accompanying approach to the digital twin and both together are the main ingredients for the digital transformation.

Indeed both are highly relevant. In this essay, we define our view of what a digital thread should be, how it elated to digital twins and how both can be used successfully in industry and business.

There are various interesting but also conflicting definitions, such as

  • “Digital thread is a communication framework that connects traditionally siloed elements in manufacturing processes and provides an integrated view of an asset throughout the manufacturing lifecycle.” (by Diann Daniel, techtarget). This is a rather technical definition obviously concentrating on the communication framework, but disregarding the interplay of the assets and services needed above pure communication. It also focuses on production elements only and disregards development.

  • “Simply stated the digital twin is the current representation of a product or system, mimicking a company’s machines, controls, workflows, and systems. The digital thread meanwhile is a record of a product or systems lifetime, from its creation to its removal.” (by Carlos Miskinis, Challenge Advisory LLP) The digital thread thus would be a portion of the digital twin’ models and the digital shadow that collects data of a system. Again the development models about the system are neglected.

  • “A digital thread creates a closed loop between digital and physical worlds to optimize products, people, processes, and places. With the technologies available today, a holistic digital thread spans the entire product lifecycle that takes place within a company and extends outward to suppliers, customers, and products and people in the field.” (from PTC). This definition is rather focused on business, and not exactly a formal definition but a very good explanation of what a digital thread is good for. With its explicit focus on closing the loop between product and digital twin of it it enforces a holistic viewpoint. The entire product lifecycle can can be spawned very wide including development and all its development artefacts.

  • “The digital thread is a critical capability in model-based systems engineering (MBSE) and the foundation for a digital twin.” (from Wikipedia). While the definition refers to MBSE, which is indeed a critical part of digital twins, the definition as such is relatively high-level and probably also inaccurate, because it ignores production data.

  • “Digital thread is defined as the use of digital tools and representations for design, evaluation, and life cycle management.” (from Wikipedia). This is a relatively weak definition, because it only refers to usage of tools. Thread as an activity?

Conclusion?

There are of course plenty of more definitions, but we no concentrate on our own conclusions.

When looking at our definition of a Digital Twin, we identify that it includes data about the system in operation (the digital shadows), but also all kind of relevant information that is created maintained and evolved during the development of the physical system (the models of various forms). It does not yet add explicitly mention the data about the production of the physical entity, which is a connection between the development models on the one hand and the operational digital shadow on the other hand.

TODO Frage: Would it make sense to explicitly extend the DT definition to make this kind of data (Structural production data?) visible (below is the old definition)

Definition of Digital Thread

Definition: Digital Thread

A digital thread of a system is that subpart of the Digital Twin that concentrated on the development, evolution, production, maintenance, installation and similar activities of a system.

It thus contains

  • a set of models of the system and
  • provides a set of services to use both purposefully with respect to the original system (under development).

The digital thread is mainly used during production of individual entities of the physical system, but reaches back to development.

It may also be noted that that digital thread contains a collection of data about the produced products from the organizational viewpoints of the products. From the viewpoint of the production engine this is just part of the data lakes.

All further discussions on Digital Twins can be found at our above mentioned Definition of Digital Twins.