Methods for 100% test coverage at the assembly level.
While Lean manufacturing strategy is discussed in relation to test strategy, it often focuses on defect mitigation strategies such as integrating program, pack and test activities to minimize variation and transport. However, a Lean manufacturing philosophy can provide even better guidance as companies navigate test strategy options. There is one hurdle to overcome. Google the question, “Is test a value-added activity?” You will see answers in Lean manufacturing forums that range from “if the process is in control you don’t need to test” to “yes, if the customer is willing to pay for it.”
When commercial AOIs were not up to the task, a little internal ingenuity saved the day.
While there is great debate in the quality community as to who first made the observation that visual inspection by humans is not 100% effective (both W. Edwards Deming and Dr. Joseph M. Juran have been given credit) and even some debate about the true effectiveness rate (is it 75%? 80%? 85%?), all agree it is inefficient and error-prone. Yet, automated optical inspection is often deemed not cost-effective for relatively simple processes in many factories.
One area that is often problematic for electronics manufacturing services providers is odd-form part through-hole insertion. Through-hole odd-form parts continue to be used when a part’s weight or need for a more robust solder joint makes that level of interconnection more reliable. Transformers, large capacitors, diodes, relays, connectors and pressure sensors are few examples of parts that are often still packaged as through-hole. Manual assembly, like manual inspection, is prone to variation and associated defects, particularly issues such as misaligned parts, missing parts or wrong parts. Odd-form parts are typically of a size or shape that makes automated insertion methods impractical.
Is there a single approach to harmonizing MES and traceability procedures?
The electronics manufacturing services industry is a form of controlled chaos. Each factory supports multiple customers in multiple industries with a variety of regulatory, industry-specific and company-specific data collection requirements. Demand among programs also varies. Some programs may be high volume and very predictable, while others have varying demand or high product mix. Not surprisingly, most EMS companies address these challenges with a combination of third-party and internally developed systems that automate data collection and analysis. This effort to address a wide range of evolving customer requirements can drive system redundancies over time, however, particularly when an EMS company has multiple facilities.
From a Lean perspective, a streamlined approach with standardized equipment and processes both inter- and intra-facility is desirable because standardization minimizes the non-value-added work driven by variation and can increase available capacity in automated processes. The challenge when standardizing internally developed software among multiple EMS facilities is that often the needs of a particular group of customers influence internally developed system design at each facility. Consequently, focus on system standardization among facilities often requires focus on process standardization as well.
Cutting time-to-market and shipping errors using Lean principles.
OEMs “new to outsourcing” represent a special challenge for electronics manufacturing services providers because often their systems and processes are not as defined and documented as those of companies that regularly work with EMS partners. Nevertheless, such OEMs also represent the segment of EMS customers able to leverage the most value from a successful outsourcing partnership, provided the EMS company properly sets expectations. Lean manufacturing philosophy’s focus on process improvement and elimination of non-valued-added activity provides an excellent roadmap in this expectation-setting process.
The seven wastes provide ample guidelines for areas of improvement in transitioning new-to-outsourcing projects:
Simple fixes are often the best solution for small variances.
In a perfect world, manufacturing process setup should eliminate the potential for mistakes. In practice, however, process complexity and the impact of system variation makes that impossible. Consequently, organizations committed to the efficiencies of Lean manufacturing often use a range of tools to identify and eliminate defect opportunities from their process.
SigmaTron International’s Tijuana, Mexico, facility uses a number of these tools in this process. During project launch, advanced product quality planning (APQP) failure mode and effects analysis (FMEA) is used to set up the most efficient, defect-free process. The product part approval process (PPAP) is used on automotive projects to validate the process, while customer-specific validation processes are used for projects in other industries. Once production is ongoing, statistical process control (SPC) and other forms of quality data collection and monitoring are utilized to monitor processes and track defects. When defects occur, a kaizen event is scheduled, and tools such as 8D problem-solving, Six Sigma’s Define-Measure-Analyze-Improve-Control (DMAIC) and poka yoke are applied to analyze and correct the root cause.