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When quality management systems (QMS) or manufacturing execution systems (MES) in electronics manufacturing are discussed today, a new buzz word keeps flying around: interoperability. There is good reason for the excitement in cost and quality ROI. Bruce Isbell and Jay Gorajia, Valor Computerized Systems Ltd., provide real-world examples.
Year after year, the same two market pressures drive factories to improve and expand production and quality management: customer satisfaction, and reducing the cost of quality. The degree to which these pressures are addressed significantly affects competitive advantage, for the vertically integrated OEM and the EMS provider. New software advances are enabling a higher level of business intelligence via low-cost real-time interoperability between ERP, CAM, QMS, and MES applications, linking highly useful information across the value chain. Well-designed applications can deliver instant information of extreme value to the electronics manufacturing operation, all because of interoperability. Cross-linking applications such as CAM, design for manufacturing (DfM), planning, execution, traceability, and quality connect these often separate silos of data. The result is the immediate visibility of better information building actionable intelligence for troubleshooting process issues and tracking operational performance (Figure 1).
Figure 1. Cross-linking data.
Consider a common function of MES tools: component traceability. In a common scenario, multiple approved vendors supply the equivalent internal part number (IPN) for a component used at specific reference designator locations on one of the PCBs being produced. Many MES applications exist that can capture the trace data for the component, such as lot code or date code, manufacturer name and manufacturer’s part number (MPN), and track this trace data to the production work order on the shop floor, or even to the PCB serial number.. It gets interesting when several vendors are thrown into the mix for the same component being placed on multiple SMT lines, but good traceability software can easily keep track of the manufacturing details and preserve the data chain for accurate traceability reporting.
Now, what happens when inspection or in-circuit test (ICT) data reveals a yield loss due to failures occurring at that specific reference designator being supplied by multiple vendors and being placed on multiple SMT machines? At this point the realm of MES needs to intersect with QMS to provide real answers.
A common function of QMS tools is to collect all the data from inspections, whether automated or manual; and from testers, whether ICT, flying probe or functional. Failure data can be instantly analyzed in real-time to spot trends or trigger a line stop if the same defects repeat themselves consecutively or reach a control limit. In our sample scenario, the QMS application has raised a red flag because too many failures are occurring at our specific reference designator location. The repeating, though sporadic, failure mode is an open solder joint due to a misplaced part caused by poor alignment to the solder pads. Since there are many factors that influence placement accuracy, the quality manager needs to know which solder stencils and SMT machines were involved in the specific failed PCBs and which feeders were used to convey the parts in each case to the offending references designators. This is where interoperability brings value, linking the realm of MES manufacturing data with QMS quality data.
Figure 2. Connecting test results to supply chain.In an actual troubleshooting process exactly like our example, the assemblers were able to correlate, with a lot of hard work, each failed PCB back to each line and to the specific SMT machine where the offending reference designator was populated. They checked the stencils, machine programs, machine set up, nozzles, and specific feeder IDs for any evidence that could explain why some boards failed and others passed. After several hours of digging, they could not determine a root cause. While the troubleshooting team searched for answers, the production line was stopped at an incredible cost to the factory. Finally, they noticed that one particular vendor’s part was a slightly different color than the other vendor’s part. One SMT machine on the offending line had a much older camera for its machine vision than those on the other lines. Whenever there was a combination of the off-color vendor component being run on the SMT line with the older camera, the part was often misplaced and out of alignment beyond what the solder reflow process could correct. Otherwise, everything ran fine. The real-time business intelligence brought by interoperability drastically reduces troubleshooting time to find a process solution to complex problems (Figure 2). Isolating root cause of test failures by connecting QMS data with manufacturing data, trace data, and the supply chain can quickly determine if supplier quality is impacting the cost of quality in a negative or positive way.
Business intelligence brought by interoperability that instantly cross links component trace data with production and quality data from test and inspection can give immediate visibility to issues that correlate to the supply chain. In many types of production, especially high-volume consumer products such as cell phones, there is fierce competition among component suppliers to get “designed in” or at least added to the approved vendor list (AVL). Component suppliers face immense pressure from OEMs and EMS companies to cut costs. Systemized interoperability can instantly alert management when quality data on the shop floor, including back-end systems-level testing, correlates to a particular component supplier. Objective data, instantly available and highly visible, is the best way to keep the supply chain accountable for their contribution to the expected quality of the final product, or not, as in the case above. When re-negotiating supply contracts, there is no replacement for real-time objective evidence that links the supplier to episodes that have the potential to harm the OEM brand or raise the cost of manufacturing.
Cross linking data can also hugely benefit intelligent materials management. Typically, stock room supply and kitting solutions are driven by ERP or ERP add-ons. These tools seldom have real-time access to material status, locations, usage, or spoilage on the shop floor. New technology provides low-cost interoperability between classical ERP functions and MES by leveraging critical information between systems. MES solutions may have all the details about material consumption, dry storage inventory, machine set ups, moisture sensitive device (MSD) expiration times, or excess inventory onboard an SMT machine, but how can this real-time information be used to support intelligent, lean kitting operations? Most ERP solutions have limited if any connection to real-time shop floor processes in which materials are consumed, moved, lost, or scrapped. Passing real-time MES part number quantities by individual feeders, shop floor inventory locations, and also tracking production rates for each line every 30 minutes or so back to a stock room kitting application can result in kits being moved to the shop floor in a just-in-time fashion. The value of interoperability in this regard is matching the material flow to the real production needs, so that excess materials are not needed as buffers against the infamous black hole caused by a disconnect between ERP and the shop floor.
One of the main enablers to business intelligence is interoperability. One of the reasons that low-cost interoperability has seldom, if ever, been achieved is the absence of robust application programmer interfaces (APIs) designed into products being brought to market. Well-designed API greatly simplify the process of interconnecting data flows between systems, breaking down the information silos in the value chain. The alternative has been the much more expensive process of making or buying highly customized software solutions. Manufacturers looking for the high value of instant business intelligence should explore the interoperability between CAM, ERP, MES, and QMS solutions found in today’s lean software constructed with powerful APIs. Transforming data-driven environments into cooperative information-driven environments is the key.
Bruce Isbell, senior strategic marketing manager, Valor, may be contacted at (512) 931-1090; firstname.lastname@example.org. Jay Gorajia, VP of support and professional services, may be contacted at (949) 586-5969; email@example.com; www.valor.com.