A positive counterbalance for mitigating inflation.

Ideally, design for excellence (DFx) should optimize and standardize every product and associated manufacturing processes to achieve high throughput and eliminate defect opportunities. While Lean original equipment manufacturers (OEMs) may reach those lofty goals in their facilities, electronics manufacturing services (EMS) environments rarely achieve them. In these environments, OEMs control their designs and much, if not all, of their approved material list (AML).

While some customers are partners with their EMS providers in DFx endeavors at the design phase, others have completed costly validation processes that limit their ability to make changes. Lean Six Sigma gives EMS continuous improvement teams the tools to identify and address inefficiencies, even when there is limited ability to modify the design. Here are a few examples of ways Lean Six Sigma core tools can be applied to improve throughput and quality.

Thorough problem identification. The DMAIC (define, measure, analyze, improve and control) process enables teams to go through a series of focused steps that identify an issue, utilize standardized tools to measure the process under study, test improvement assumptions and implement a validated solution to eliminate the issue or improve overall efficiency. This approach particularly benefits the EMS environment because it generates documentation that helps customers’ teams easily understand identified issues, the proposed tooling or process changes and the validation processes used to test the recommendations.

Mistake-proofing. Poka-yoke, the Japanese term for mistake-proofing, was introduced by Shigeo Shingo as part of the Toyota Production System (TPS). When applied, the resulting process improvement eliminates a specific defect. Its focus on simplicity is its strength because simple fixes are often the best solution for small variances in the manufacturing process. Simple fixes are also easy to implement quickly and encourage production operator involvement in the pursuit of product perfection.

In the EMS environment, poka-yokes are beneficial because they improve throughput or mitigate defect opportunities without product design or process changes.

Poka-yoke focuses on three types of solutions:

• Contact type – eliminate defects caused by variation by making variation impossible.
• Constant number/visual management type – an error signal is triggered if a specific number of movements or steps are not completed.
• Performance sequence/failsafe – if steps are not completed in a specific order, the operator is locked out.

The contact type of poka-yoke is most commonly used to address throughput or design-driven quality issues. For example, at SigmaTron, 3-D-printed fixturing is often used to help operators place odd-form parts faster and more accurately or measure dimensions to ensure correct height or alignment. This can be particularly important with legacy products with designs that limit automated production options. The other two types of poka-yokes are normally found in the manufacturing execution system (MES), which supports enforced routing protocols.

A culture focused on continuous improvement. Lean Six Sigma educates employees on the “why” behind continuous improvement. Employees trained to recognize the seven wastes or maintain a 7S workplace are thinking about the impact of inefficiency or lack of organization every day. They work smarter and exercise discipline in organizing their workspaces and maintaining the equipment they use. In multigenerational workplaces, where younger employees want to make an impact, a Lean Six Sigma environment provides a path to make measurable contributions through improvement ideas.

Improvements stick. The benefit of a focused approach to continuous improvement is that as issues are identified and addressed, the need for corrective action is reduced. For example, in 2024 the team at SigmaTron’s Tijuana, Mexico, facility cut the number of kaizen events needed for its highest-volume automotive customer by 50% because the previous year’s projects stabilized manufacturing processes through automation or fixturing, reducing variation.

Lean Six Sigma benefits EMS customers in other ways. Quality and throughput improvements can enhance response to increases in demand. Continuous improvement efforts also help eliminate unnecessary costs, which can be particularly beneficial in inflationary environments. Reviewing kaizen events associated with specific products can also help design teams improve manufacturability or testability of future product generations.

Incorporating Lean Six Sigma with Industry 4.0-capable equipment can improve equipment maintenance practices and overall yield by identifying tooling wear or process-related issues earlier than an operator alone would. In short, the problem-solving tools and disciplines utilized by production personnel in Lean Six Sigma environments drive improvements relevant to the EMS-OEM relationship in various ways.

Filemon Sagrero is the Continuous Improvement Engineer and a Six Sigma Black Belt at SigmaTron International’s facility in Tijuana, Mexico.