An original equipment manufacturer (OEM) called the EMPF Helpline, asking for assistance with electronics manufacturing services (EMS) provider qualification for their advanced digital signal processing (DSP) product line for critical DoD applications.


Increasingly, OEMs are recognizing the benefits of concentrating their in-house skills and resources on product design and marketing, while simultaneously subcontracting their manufacturing requirements. The reasons are varied, ranging from the massive capital expenditure required to process the latest electronics packaging technologies, to the rising tide of issues surrounding RoHS (Restriction of Hazardous Substances directive) and REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) legislation.

However, OEM purchasing departments know that choosing the right manufacturing partner is potentially the single most important sourcing decision the company will make. With OEMs increasingly relying on manufacturing partners for their future production capacity, it is vital for customers to be able to differentiate between suppliers.

This OEM recognized the importance of having the right skills available to qualify their EMS provider. They requested that the EMPF provide the technical auditors that would team with their quality personnel to survey and audit the targeted EMS providers.

The customer needed experts in IPC-A-610 Class 3 (Acceptability of Electronic Assemblies), mechanical design and manufacturing, component derating, thermal analysis, functional and performance testing, and environmental testing. They did not expect that any one vendor would be able to provide all the manufacturing functions, so specialty vendors were targeted to be surveyed. Additionally, the customer preferred vendors located in their region.

Approach
The EMPF has extensive expertise in high reliability electronics manufacturing. We conduct training and certification on all levels of IPC standards. Additionally, the EMPF has been involved in the development of risk mitigation and training of lead free electronics manufacturing for a number of years.

The EMPF recommended that an additional area to audit should be included: the EMS provider’s Lead Free Control Plan in accordance with GEIA-STD-00005-1 requirements. Among the many concerns relative to electronic assembly, is the mixing of RoHS-compliant and non-RoHS compliant components on the same printed wiring assemblies due to the availability of components. Such mixing is becoming a practical necessity for many high reliability electronic assemblies used in military and aerospace. Formerly, these critical assemblies were assembled exclusively using the familiar tin-lead solders, component finishes, and board finishes. However, as the majority of commercial electronic applications switch to the European-mandated lead-free requirements (RoHS-compliant), mixed SnPb/Pb-free components are inevitable.

The major risks confronting products which introduce Pb-free electronics into their bills of material may be divided into two categories: product reliability and product sustainment. Product reliability encompasses those risks which impact the reliability of the product required to operate as desired in a defined environmental applications for its contractual service life. The primary product reliability risks related to Pb-free electronics are the premature failure of the solder joint interface and functional failures caused by tin whiskers. Both reliability risks are addressed in detail in this document. Product sustainment includes those risks which impact the projected lifetime of the product to include its availability and total ownership costs. These general risks may be further subdivided into the risk factors shown in Table 2-1.

The structure of the site surveys were organized by function. The functional categories were Lead Free Control Plan, component derating, thermal analysis, board manufacture, board assembly, functional testing, environmental testing, and final performance testing. The EMPF coordinated with the customer’s Quality Auditor to prioritize and schedule the site surveys. Results and recommendations were provided at the conclusion of the surveys. The EMPF utilized a grading system based on predetermined criteria so that the team was not comparing vendors to vendors, but vendors to an established standard.

Result
The customer was pleased to find that there was an EMS provider in their region that met all of their criteria. When they received their contract they were able to engage their qualified supplier with confidence.

Contact the EMPF Helpline at 610.362.1320 for more information.