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78 SMT Magazine • September 2016 data are captured automatically by way of inte- gration or interfacing with operational and sup- porting systems, ensuring no data are lost or de- layed. The use of level 4 traceability data, there- fore, is compatible with updates and mainte- nance of live dashboards showing various key performance indicators (KPIs). Figure 3 provides recommendations for mapping IPC-1782 levels of traceability to the IPC Product Classification System. The classifi- cation and the final choice of traceability levels shall be AABUS. Hierarchy of Traceability Data The adoption of a hierarchy allows a com- plete tree of traceability data to be constructed, linking together different "cells" of data that de- scribe different elements of the traceability data. The uppermost head of the traceability data is likely to the completed shipped product. This product will contain sub-assemblies and com- ponent materials, each of which may have their own tree of traceability data cells linked. In this way, critical components can be traced all the way back to the fundamental manufacturing processes where the need exists. Figure 4 pro- vides a visual representation for the cell struc- tures belonging to a defined assembly, showing how sub-assemblies are related, each of which is the head of another traceability cell structure. Traceability Data Cells The tree is made up of different cells of data, each type of which are populated according to the designated level of traceability, either ma- terial or process. Cells link together so as avoid unnecessary duplication of data. For example, a reel of materials may be used on an SMT place- ment machine where many PCBs are populated. The traceability record for each PCB will con- tain the ID of the material used, which refers to another cell that holds the actual traceability data of the reel. All PCBs made using that reel can therefore link to the same instance of trace- ability data, rather than containing duplicate copies. This very much ensures that the trace- ability data is consistent and concise. While this paper seeks to summarize the defined content, the full detail can be found in the draft working document of the IPC-1782 standard. The cells currently defined are as follows: Assembly Cell: • The Assembly Cell is the head of the traceability structure. For a complete product, the Assembly Cell refers to the final product, by serial number if it exists. • The Assembly cell also represents sub- assemblies which themselves have a tree of traceability cells linked to them. • The associated data within the Assembly Cell is as follows: • Production Bill of Materials (BOM): Components and sub-assemblies – Where possible, components should be referenced using an individual unique reference designator. – Components without a unique specific reference designators should be called with a standard descriptive name (such as screws, M3, 5mm) IPC-1782 STANDARD FOR TRACEABILITY SUPPORTING COUNTERFEIT COMPONENT DETECTION Figure 3: Traceability level to product classification system matrix.