Ensuring supply chain quality

SigmaTron International’s
corporate director of quality and compliance,
Allen Abell

SigmaTron International’s corporate director of quality and compliance, Allen Abell, explains how EMS companies are gatekeepers of quality between OEMs and part suppliers.

The benefit of outsourcing to an electronics manufacturing services (EMS) provider goes beyond its manufacturing capabilities and expertise. Outsourcing leads to the EMS provider supporting management of the component supply chain. This translates to reduced transaction and administrative cost for many purchasing organizations. That said, it may also change the dynamics by which part suppliers are measured. Consequently, it is as important to review an EMS provider’s processes for maintaining quality within the supply chain as it is to audit their processes for ensuring manufacturing quality within their own operations.

SigmaTron International takes supply chain quality seriously. Many of its customers require zero to 50ppm failure rates for finished products and that means even small issues in supply chain quality can impact overall quality scores.

As a result and as circumstances warrant, fabricated component suppliers are asked to complete a self-audit and provide applicable documents such as a copy of the development manual, control plan, PFMEA, internal and external PPM data, quality reliability and test equipment list and other documentation as needed. If subsequent scores indicate a need for improvement, this EMS provider, often in coordination with the customer, assigns a supplier quality engineer (SQE) who works with the supplier to meet the improvement goals.

In cases where the results of the self-audit or quality issues drive the need for additional scrutiny, a virtual or onsite audit may be conducted by the EMS provider. At SigmaTron, audits for North American suppliers are conducted by a local team and audits for Asian suppliers are conducted by a team from its International Purchasing Office in Taiwan.

In the OEM world, poorly performing suppliers are often eliminated or designed out in favor of alternates meeting quality criteria over time. In the EMS world, customer preference may dictate that a poorly performing supplier must stay on the approved materials list (AML) due to excessive requalification costs or a need to use a legacy part with no alternate choices.

While the responsibility for those supplier choices remains with the OEM, the unnecessary cost impact of poor supplier quality is felt by both the OEM and EMS provider. This EMS provider’s SQEs use continuous improvement methodologies such as the Five Whys process and Eight Disciplines (8D) to identify root causes and drive continuous improvement at suppliers who are not meeting quality criteria. For example, when an electronic membrane switch supplier was not meeting quality requirements, the assigned SQE evaluated its processes and had the supplier modify its assembly and test process to improve overall process control and ensure 100 per cent test of critical to quality (CTQ) requirements.

When an OEM outsources manufacturing to an EMS provider, they are also outsourcing their brand since end customers only see a product that works flawlessly or fails. An EMS provider’s ability to set high standards for its supply base and/or drive improvements in customer-required suppliers is one element in ensuring that brand integrity is maintained. The outsourcing relationship and overall quality is further enhanced when OEMs listen to their EMS providers’ recommendations on alternatives to poorly performing suppliers on their AML.