Product and component traceability: a complete traceability system will minimize the cost of product recalls and help eliminate them in the future.

Product recalls are a costly and time-consuming process. Without adequate traceability, many products will be recalled for repair or replacement, even if a large number of the units are not faulty. In the next few years, regulatory and product liability requirements will mandate product traceability that extends throughout the entire supply chain.

Today, few manufacturing enterprises implement product and component traceability systems. Often, these systems do not extend outside the manufacturing environment because of inconsistent strategies for tracking products and raw materials from various suppliers, manufacturing plants, distribution centers and transportation providers.

A defective product can be the result of a fundamental design error or a flaw in the manufacturing process. In the case of a design error, the entire product shipment must be recalled to correct the error. However, a flaw in the manufacturing process may have been a temporary condition, limited to a small batch of product. In this case, a recall of the entire delivered product is not necessary or cost-effective.

To perform a sufficient and cost-effective recall, manufacturers must have the data necessary to determine which specific products were built with the defective part or faulty process. A traceability system has two primary goals:

* Help to minimize the number of products that have to be recalled or returned when a manufacturing flaw is found, by identifying only the specific serial numbers that were built with the faulty component or the faulty process.

* Help to eliminate returns by providing reports on the machines, components, stations, shifts and operators involved in the assembly of the defective product. This goal will help managers to adjust the manufacturing process so that more defects are detected before shipment.

This article will provide an overview of the issues driving the need for improved product and component traceability and will describe the processes that can be implemented to improve product delivery and the cost of recalls.

Recall Costs

The impact of recalling millions of units of a product on an organization is tremendous. The cost of a major recall can be enormous and is influenced by many factors. Some costs are directly related to recall activities, such as investigation of the product failure, notification of the recall to customers, transportation of the recalled product, redesign and repair costs, and the value of the defective product. Other costs are indirectly associated with the product recall, including the loss of sales during the recall period due to negative publicity. Market value could also be decreased following the announcement of a recall, which is often reflected in a lower stock price of the organization. The bottom fine is that a product recall can have a dramatic effect on a company's profits.

Overall Traceability Goals

Electronics manufacturers must find ways to reduce the cost of product recall events. A system that can quickly and accurately provide information on the exact product lots to be recalled is needed. The extent of the recall may be restricted by allowing the manufacturer to recall only those products in which the defective component was used.

In addition, electronics manufacturers must continuously improve their processes, with the goal of delivering products with no defects. This goal is in line with the objective of the six sigma initiative, which strives to improve customer satisfaction by reducing defects in products. To move toward six sigma, manufacturers must have the ability to trace the manufacturing process and detect a nonconforming process during production, or at least before the product is shipped to the next link in the supply chain.

Properly implemented, a traceability system will enable manufacturers to better control the quality and performance of their manufacturing processes. The result is reduced cost and a continuously improving manufacturing process, both at the planning and execution stages, in terms of product quality, throughput and profitability.

Planning and Execution Systems

Typically, two types of systems are used in the manufacturing environment: planning systems and execution systems. Both of these systems help manufacturers achieve the goal of six sigma.

Planning systems are used to design, optimize and validate the new product introduction (NPI) processes. Assembly and test planning software enables original equipment manufacturers (OEMs) and electronics manufacturing services (EMS) providers to introduce new products to the shop floor quickly and accurately, improving the overall time-to-market and time-to-volume.

Manufacturing execution systems (MES) track products and manage work orders on the factory floor. A MES makes use of real-time data collection to allow manufacturers to analyze and manage processes across the extended enterprise. It provides drill-down capability to detailed shop-floor data, including material tracking, performance monitoring and quality management. It supports process or schedule changes by electronically dispatching updates directly to the shop floor personnel. And it provides the mechanism to continuously improve quality and to reduce costs by process enforcement and early problem detection and correction.

The Link: Traceability

Process planning and MES are the foundation for traceability. By linking the planning systems with the execution systems, electronics manufacturers can achieve product and component level traceability. Specifically, a traceability system is a combination of NPI planning, material management, performance monitoring and quality management. This system captures detailed manufacturing process information from the shop floor, compares it with the planned manufacturing process and reports or alerts the user to any gaps. It also provides detailed historical data on the production process for any given work order.

The necessary elements of an ideal traceability system are identification, tracking and process management and verification. These elements must be automated as much as possible and must be implemented in such a way as to minimize any impact on the current production process. Traceability information must also be collected from a multi-vendor environment, which is the common situation in electronics manufacturing.

Depending on the maturity of the planning and execution systems, different levels of traceability can be provided. Minimally, the system must track product genealogy information, meaning that it must be able to identify which specific components are assembled into which products. In this sense, component refers both to a single, discrete element, such as an integrated circuit (IC) chip on a printed circuit board, and a pre-assembled unit that is part of a larger assembly hierarchy, such as a motherboard in a personal computer (PC). In the event of a recall and the identification of a defective component, the traceability system will provide a detail of the other products, by serial number, that were built with the same lot of defective components.

The second level of traceability tracks process-related information, such as when and where a specific part was assembled, which machine or device was used, and who performed the operation. Process-related information also contains any real-time errors that occurred during the manufacture of the product, such as feeder or nozzle errors on an automatic assembly machine. In the event of a recall, this level of traceability provides additional drill-down capabilities to determine the root cause of the defect from a process perspective. In addition, a comparison between the planned and the executed manufacturing process may help to identify nonconformities prior to shipment, eliminating the need and expense of recalling the product from a customer.

Finally, integrated process management and verification functionality helps to identify and prevent any errors in production. The system has the ability to manage the execution of the process by interactively guiding the users through required tasks and preventing them from performing a nonconforming process task in real time. For example, the system identifies for the user which specific parts must be loaded onto a machine for the current order. And, when the part is loaded onto the machine, the system provides a mechanism for verifying that this is the correct part-feeder-slot combination. If an incorrect combination is detected, an error is generated, which must be corrected by the user.

Results

A large amount of data is collected by the traceability system throughout the setup and execution of the production process (Figures 1 and 2). During the setup of production, the specific part lots at each process station are recorded. During execution of the process, the specific genealogy of each product is recorded, by knowing the time that each product is assembled at each station. Also, process errors are collected in real time during production. Now, given all this data, several different analyses can be performed, including corrective action and root cause analysis.

[FIGURES 1-2 OMITTED]

The manufacturer needs to know:

* What component failed?

* Exactly what product serial numbers included this component and need to be recalled?

* Exactly what manufacturing process did products with the defective component go through?

* How can the process be improved to detect such defects in the future?

When a product has been returned by a customer, or a defective product has been identified by some other means, a failure analysis is performed to identify the defective component. Once the defective component has been identified, the traceability system produces a report with detailed information about the component, including lot number and vendor.

The next step is to determine where the defective part was used in production. A defective lot of components may have been used in several products, which are now faulty. Or, unused components from the defective lot in inventory or another storage location must be retrieved to prevent them from being used in production. Therefore, given the lot number for a specific part, the system generates an analysis of all products, product lots and product serial numbers that have been produced using that particular set of parts. Also, the location of any used material from that lot is displayed.

After analyzing all affected products, manufacturers need to determine the root cause of the problem. The manufacturer must be able to trace the defective product back through all production and inspection phases to the raw materials, specific equipment, and personnel used in the manufacturing process to apply corrective action. Given a specific component lot number, the system will provide a comprehensive list of all actions taken with that specific part and which specific operator performed those tasks.

Further drill down provides data on specific process abnormalities that may have occurred during production to cause the defective component. Examples of process abnormalities are feeder or nozzle errors or inappropriate storage of a component or assembly. Faulty products may share common conditions, such as a common process or common supplier, which can be corrected to improve product quality. Suspect material is traceable to a specific piece of equipment, supplier, operator or inspector, or shift, and production time. The correlation of error information and historical process data allows manufacturers to implement corrective action.

Conclusion

In the next few years, product and component traceability will be mandated, either by customers or regulatory requirements. One reason for this requirement is the extremely high cost of a product recall for an organization. To achieve the necessary level of traceability requires a link between the manufacturer's planning and execution systems. A complete traceability system will minimize the cost of product recalls and help to eliminate them in the future.

With information on the specific genealogy of each product, the traceability system can reduce the costs of a product recall by recalling only the product that was built with a defective component or process. In addition, the system provides the information necessary to continuously improve the manufacturing process to achieve six sigma.

Properly implemented, a traceability system enables manufacturers to better control the quality and performance of their manufacturing processes in a mixed-vendor environment. It reduces the manufacturing cost of quality. The result is improved customer satisfaction through fewer defects in delivered product and increased profits for the organization.

John Nelson is director of R&D with Tecnomatix Unicam, Inc., Portsmouth, NH; email: John.Nelson @unicam.com.

A version of this article was originally presented at APEX 2003.