Lots of companies are familiar with lean manufacturing concepts and have successfully used these techniques to improve manufacturing processes. Lean techniques, while most often used in printed circuit fabrication and assembly operations, can also be applied to nonmanufacturing processes. One such process is new part number introduction (NPIP). The main thrust of lean manufacturing is to reduce or eliminate waste. There are typically seven wastes (mudas), as defined by Toyota executive Taiicho Ohno, when he developed Toyota’s Production System (TPS) [1] (” Muda” is a Japanese word meaning uselessness, idleness or other synonyms of waste.) The seven mudas are: – Transport
– Inventory
– Motion
– Waiting
– Over-processing
– Over-production
– Defects
The common part number startup for flexible PCB often can suffer from a number of those wastages. Particular waste items are specific to a part number (customer out of office, conflicts in documentation, iterative design discussions, etc.) or be implanted as accepted gaps in a supplier’s product launch system. As part of a continuous enhancement mentality, wastes should be identified for reduction through a documented and tracked part number introduction procedure.
Some of the more common waste elements are:
Transport: In a new part number introduction process (NPIP), transport is the movement of documentation (electronic or paper) from one department to another requiring successive reviews and sign-offs. Excess transport is a symptom of a departmentalized approach to part number start-up rather than a process flow approach. A cross-functional design review team with one leader can help and remove departmental barriers assure that reviews and inputs are done in parallel rather than serially. Transport can also include sending info requests and approvals to clients and providers. These demands need to be challenged regarding their usefulness and necessity.
Waiting: New part number start-up requires information flow. When someone is waiting for information, oftentimes the process becomes stalled at various steps. This can happen from within the company, the customer, or the supplier. A good NPIP system includes checklists so the needed documentation is quickly identified and missing parts can be requested immediately. Team members are focused on rapid communication so that there is as little waiting time as possible. Customers, inner team members, and suppliers all need to be intimately involved to foster good communication. Again, parallel processing is an important notification. Sometimes a decision followed by a course adjustment, is a faster journey to the destination than waiting for all the information to become available.
Over-processing: In the design and launch startup system, the matching of over-processing is over-specification. Because designers believe it gives them a larger safety margin, it is tempting to specify a tighter tolerance than required. While this is sometimes the case, other times a tighter tolerance will push a supplier to make compromise that reduce producing yields, require additional tooling, and add time to the processing sequence. When permission criteria are defined in absolute terms, additional delays occur. Criteria specifying “no stains” or “no foreign material” can create an inspection struggle until a meeting of the minds occurs between the customer and supplier. Having a well-documented layout and design guide, as well as having knowledgeable manufacturing technicians on the startup team, will assist guarantee that a new part number launches with reasonable production yields and meets the customer’s requirements.
Over-production: The matching of overproduction in a part number start-up system is over-design. As in the case described in overprocessing, designing in “safety margins” might be desirable, but it can also backfire. An instance in the world of versatile circuitry might be specifying thicker copper to allow higher amperage capability, but thicker copper can also degrade flexibility. Over-design might also add cost, so one needs to comprehend if the added cost truly yields a more reliable product.
Defects: The outcome of a poorly executed part number introduction may result in low production yields causing high scrap rates, late deliveries and possibly malfunctioning product delivered to the customer. A startup process should certainly be rigorous enough to avoid pitfalls seen on previous part numbers. It’s not possible to get everyone review each part number prior to product launch, but utilizing multiple subject matter professionals to preview design layouts is a good first step. Capturing the cooperative wisdom of the organization is the goal as this can guide identify “gotchas” that can be avoided. This review should be considered a proactive step but in the world of custom made flex PCB and heaters even the best plans may result in surprises. A team focused on quick reaction is critical when this happens. When the demons inevitably are revealed, the best NPIP system is a combination of pre-launch proactive review and a reactive team ready to respond quickly.
It is a continuous enhancement effort plan to supply intensified customer support during initial part number design and delivery. It is an approach tailored to an organization that provides custom crafted products. Similar methods and practices can help reduce the mudas encountered during part number startup.