Digital thread

The digital thread is one linked record of a product from its first design through its making and every repair, so that each stage can read what the other stages know. The word "thread" is used because the record runs through the whole life of the product, joining design, manufacturing, testing, service and sometimes recycling.

Here is how it works in general. In most companies each stage keeps its own files, in its own software. The design team keeps drawings, the factory keeps process settings and the service team keeps repair notes. With a digital thread, every record carries the product's identity, such as a part number and a serial number. So a service engineer who opens one serial number can see the design version it was made to, the machine settings used on that day and every repair since.

The thread usually breaks at the joins between departments. The design team may call a part by one number, the factory by another and the service team by a third. Without one shared identity, an engineer searches by hand through three systems, and a fault takes longer to find. A working thread keeps one part number and one serial number across all of them. Quality teams, service teams and regulators use it. Aviation regulators, for example, can ask for the full history of a part. The maker pays for it, to lower the cost of recalls and rework.

Take, for example, an aircraft engine. If a part cracks in service, the maker can look up the exact material batch and machining record of that part and find other engines with the same batch. Consider a car maker that changes the design of a bracket. The change reaches the factory instructions and the spare-parts catalogue automatically, instead of being copied by hand. For instance, a medicine plant keeps one thread that links a recipe to every batch made from it.

Such linked records are built with product lifecycle management (PLM) tools, manufacturing execution systems and service software. Together they make a digital twin possible.

How is it different from track and trace? Track and trace follows physical items through the supply chain. The digital thread links all the information about the product, including its design, its changes and its service history.