An automation shift shows how smarter processes reduce inspection and boost value-added work.
Advances in technology offer many ways to improve efficiency and reduce costs without impacting quality through automated inspection tools. The full potential of these tools cannot be fully leveraged without rethinking organization and processes, however. This month, we look at ways SigmaTron International’s facility in Chihuahua, Mexico, is evolving its inspection approach after validating the effectiveness of the automation it has been investing in over the past three years.
The facility serves customers in a variety of industries with projects ranging from low-volume, complex box-builds under 100 per day to printed circuit board assemblies in volumes of 40,000 per day. The bulk of production is in the thousands-per-day range. Consequently, there is a mix of dedicated production lines run continuously and shared production lines with multiple changeovers per day.
Over the past three years, barcode scanning capability has been added to manual inspection, automated optical inspection, in-circuit test, programming, functional test and final inspection, enabling the manufacturing execution system (MES) to implement enforced routing and automate quality data collection and trends analysis. As automation improved quality, the inspector base was reduced to 20 inspectors from 30.
The current state model had 20 inspectors/process auditors in two shifts engaged in a variety of activities, including doing process audits on SMT, automated inspections and final assembly, as well as testing PCBAs per AQL tables and documenting release model changes. They also audited material stored at the point of use in secondary assembly lines. Trend analysis suggested further realignment was necessary, however.
Analysis of the past two years of quality data showed zero defects in finished goods audits. There has been no wrong-component defect in the past three years. Auditing activity has also changed. Previously, process audits had included verifying setups. The majority of the SMT lines had been upgraded to smart feeder setups, where the feeders automatically validated that the correct reel was loaded. Auditors may still do audits on release parts for new product introduction or feeder carts loaded offline when there is a need for fast changeovers. However, 100% verification has been eliminated from SMT lines using smart feeders.
The future state model reduced the number of inspectors to 10 positions and redeployed the other 10 into other needed positions. Finished goods inspectors have been eliminated as a job position. The data highlight that automation and its associated tighter process control reduce the need for manual quality control activities, while highlighting the benefits of preventative quality assurance activities associated with new product introduction (NPI) validation, customer-driven engineering changes and processes with fewer automated controls.
In this example, quality trend data drove the realignment strategy by demonstrating where automation eliminated the need for manual inspection. The electronics manufacturing services (EMS) environment has inherent quality challenges, driven by the number of customers and the variety of projects each facility must manage. Enforced routing and automated inspection technologies ensure consistent controls that are not impacted by changes in product mix are in place.
There has long been debate on quality assurance versus quality control. Because quality assurance focuses on preventing defect opportunities, Lean philosophy treats it as a value-added activity. Quality control, which uses inspection to prevent defects from escaping the factory, is considered a necessary, but non-value-added, activity. Both are necessary in today’s manufacturing environments because smaller product footprints, narrow process windows, and high-mix production environments pose higher risks of defects. Investing in automation that eliminates the need for headcount associated with non-value-added inspection activities enables personnel to focus on the value-added side of quality activities while systems focus on identifying any defects that do slip through. It reduces the cost of quality over time and improves efficiency and throughput.
Alvaro Grado is general manager at SigmaTron International’s (Chihuahua, Mexico) facility (sigmatronintl.com).
