BACK to
Implemenation
Guidelines

Overview

Product Instance

Product Instance Identification

Breakdown Structure

Usage History

The Product Instance Schema

The Product Instance Schema centers on the following:

• Product Instance;

• Product Instance Identification;

• Product Instance Breakdown Structure;

• Product Instance Usage History.

The data structures collected under the Entity product_instance_definition are dedicated to the management of the AS-BUILT/AS-USED view of the product.

A product_instance_definition is optionally related to exactly one product_concept and to exactly one product_design_definition. It may be associated with a person and/or organization with a specific role (e.g. owner, custodian, user, driver, pilot, etc. ) through the entity product_instance_organization_association.  Additional information about the association is the date  when the association was established and the date when it was ended. History of product instance ownership, for example, may be derived by screening the start_date and the end_date attributes. The current ownership is identified by the entity instance whose end_date attribute is empty. A product_instance may be associated with a location.

The subtypes of the Entity product_instance_definition are related to the three different types of identification of a product instance. In particular, a product_instance may be identified by: (1) a serial number; (2) a lot number; or (3), for some types of material, just by a name.  A globally unique identifier consisting of the organization code and the serial number/lot number must be used. 

Figure 6.1 Identification of Product Instances

• A serial number is an identifier consisting of alphanumeric characters which is assigned sequentially in the order of manufacture or final test which, in conjunction, with the manufacturer's identification (e.g id_owner), uniquely identifies a single item within a group of similar items manufactured from the same design.
• A lot number is an identifier consisting of either a date or a string of alphanumeric characters which, in conjunction with the manufacturer's identification, uniquely identify a group of units of the same item which are manufactured or assembled by one producer under uniform conditions and which are expected to function in a uniform manner.
• The term 'material' applies to bulk items that are liquid, powder, or some other form, such that a unit of measure, other than 'each', is necessary to describe any quantity of them. Materials should be identified by an appropriate name according to industry practices. Instances of material are identified by an internal unique identifier.

During the in-service phase, the user may need to issue additional identifiers to product instance (Tail, Plate numbers) in order to manage them within the user management system. In this case, the Entity alias_identification shall be used to link the user defined identifiers with the unique product instance identifier as defined above.

 

A product instance breakdown structure is handled using the Entity product_instance_physical_decomposition.

Figure 6.2 Product Instance Breakdown

This entity captures the fact that one part (or rather a product_instance_definition identified by a serial number) is used as a component in an assembly (or rather another product_instance_definition also identified by a serial number). The entity product_instance_substitution together with the attributes date_installed and date_removed may be used to maintain a record of the product instance configuration history.

 

An important parameter to manage and support a product instance is the usage history.

 

Figure 6.3 Product Instance Usage History

The basic entities in this diagram are product_instance_definition and usage_metrics_parameter. The latter collects all the different parameters and the detection method needed to assess the current usage status of the product instance.

The intersection table between the two entities is used to capture detection dates and the detected values.