Applying the New IPC Standard for Traceability Makes Compliance and Reporting Easier
IPC has created a new standard and specification for traceability practices across all levels of electronics manufacturing, and specifically for electronics assembly. The IPC-1782 standard defines four levels for material and process traceability. With this new standard, companies that are practicing basic levels of traceability can evolve to higher levels (Table 1). Implementing this standard means that companies will be able to clearly define the expectations of what is required for compliance and conformance to customer needs.
Traceability is often a key component of quality standards across the electronics industry. But it has been approached from various points of view, and it can be defined as any combination of material traceability, product tracking, and process recording. And even within material traceability, views can differ on what should be recorded, how detailed it is, and how accurate it needs to be. Materials traceability could mean tracking specific materials to a work order, to a specifically identified PCB within a work order, or even to a specific component placement on that PCB. It may include all types of materials or perhaps only high-value, safety-critical parts or serialized parts. It may include or exclude parts replaced at repair stations or where an alternative or substitute part has been used, and it can include many more examples where a choice in the depth and breadth of recording is needed.
Table 1: IPC-1782 summary of traceability levels.
Accuracy is another area of contention. Process operational efficiency may conflict with the accuracy with which the traceability data is collected, as for example trays are re-filled without positive poka-yoke confirmation of verification. These are just some typical variations in the level and degree of material traceability. For product tracking and process data recording, an immense number of other similar decisions have to be made.
Individual companies typically have created their own set of high-level rules for traceability data that should be collected as part of their conformance requirements. The problem with all of these different specifications, often made without an in-depth understanding of the processes involved, was that exactly what data should be recorded, from where, and how it was supposed to relate to the product and process was left undefined. This has resulted in the collection of traceability data that is unreliable, incomplete, and/or irrelevant.
Negotiations around traceability requirements between the product owner and manufacturing have become increasingly difficult because neither speaks the same language, and they have common no point of view. Spectacular and public cases of product recalls have been the result, even while electronic systems are becoming more of a critical part of our everyday lives, and counterfeiters are having a significant effect on product quality and brand trust.
Compliance to internal or external standards helps assure manufacturers that work is only placed into manufacturing centers which demonstrate the appropriate compliance certificates or approvals. Today, compliance requirements extend to all quality sensitive markets for electronic goods such as military, medical, automotive, aerospace, telecommunications, and industrial controls. Even lower-priced consumer goods, such as handsets, toys, and games, require safety and environmental compliance. Manufacturers who are not able to demonstrate this compliance simply do not win business in these markets. These trends are driving manufacturers to implement higher levels of traceability for a wider range of industry segments.
The IPC-1782 Critical Components Traceability Task Group was created to address these issues. This committee has completed the first all-encompassing traceability standard for electronics, which is designed to be applicable to every product, in every company. Traceability is seen by many as a burden to the manufacturing process, and no one wants to have to comply or conform to yet another process or standard in the office or factory. The IPC-1782 committee members who all contributed so much to the creation of the traceability standard agreed that traceability ought to be implemented based on the merit that it brings to the manufacturing operation, rather than through some compliance mandate.
The nature of electronics assembly is hierarchical. A finished product, represented by an assembly cell, is typically made up of raw materials plus subassemblies. Each of the subassemblies is, in turn, a finished product of another assembly process also made up of raw materials and potentially other subassemblies. Thus, the IPC-1782 task group thought that the structure of traceability data should align with this physical reality. Figure 1 is a simple illustration of this structure.
Figure 1: The hierarchical data structure approach adopted by the IPC-1782 standard.
The assembly cell, here identified as “724435,” contains data about the work order and process sequence, BOM, the process traceability data, which is a record of events and transactions that have taken place during the assembly process, and the materials traceability data which contains information about specific raw materials, as well as other “roots” of information about each subassembly.
A raw material is defined as any component that does not have a traceability record. Because this is a modular approach, the traceability detail of subassemblies can be combined easily at a later date, either when the subassembly is used, or even later, as long as the unique ID of the subassembly is recorded. The subassembly data can later be imported or simply referred to when stored in a connected system.
Then, specific cells of information that contain different attributes are defined for each of the materials and processes. The IPC-1782 standard lists the requirements for data capture for each of these cells, relevant to the specific level of traceability chosen: M1 through M4, and P1 through P4.
In the case of process traceability, common elements of traceability data apply to all processes and then additional requirements are dependent on the specific process type. For example, common elements are process name or ID, time in and out of each PCB, etc. Specific data by machine type would include the list of materials consumed for an SMT process as well as details of machine errors during the operation, whereas a test process would include a pass and fail result, as well as process measurement data.
For all the materials identified as being used at each process, the associated material traceability data cells are referenced. Information in these cells can include unique material IDs (as well as unique carrier IDs), supplier, date code, etc. The method of linking material traceability data through the use of unique IDs and the cellular structure of the data means that, at higher levels of traceability, data does not need to be repeated within the data structure. Any specific material, identified by an ID with associated traceability data is needed only once and may be referred to from many reference designator positions on many different assemblies, and even across many different products. This helps to reduce the storage requirement for the data by a significant amount by eliminating needless duplicate data.
In addition to product specific records, the traceability structure also includes data relating to equipment maintenance, kept separate from the assembly tree structure, because it need not be related to any specific product but is time-based data which may occur while a product is being made or between products.
To read this entire article, which appeared in the February 2017 issue of SMT Magazine, click here.