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Buy GEIA HB (R) Technical Guidelines For Aerospace And High Performance Electronic Systems Containing Lead-Free Solder And Finishes. Find the most up-to-date version of GEIA-STD at Engineering TechAmerica GEIA-HB Technical Guidelines for Aerospace and High Performance Electronic Systems Containing Lead-Free Solder.

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The plan included a list of tasks necessary to provide ADHP engineers sufficient information to minimize risks associated with Pb-free solders and finishes. Martin Wickham reviewed previous findings and gave an update on current work. Environment Impact on Assembly, Printing and Reflow. As the voice of the U. It will take a combination of high-level design strategies and an effective set of guidelines to enable the ADHP engineer to develop mission-successful products and systems.

A series of collaborative projects had been carried out at the National Physical Laboratory to evaluate conformal coating as a tin whisker mitigation strategy for printed circuit assemblies. The higher current densities tended to favour the formation of large eruptions, rather than filament whiskers. You can download and open this file to your own computer but DRM prevents opening this file on another computer, including a networked server. This standard is also available to be included in Standards Subscriptions.

The space environment presented particular challenges to electronic systems: Dr Dunn had collected data on whiskering effects over a period of 32 years, using the C-Ring test to introduce tensile and compressive stress, with different metal substrates, barrier layers and tin plating thicknesses, and the results were shortly to be published.

Tin Whisker Mitigation Methodologies: Report from SMART Group, Part 1

In summary, as the standards had evolved, they had become increasingly definitive with regard to component-to-component spacing design rules. An additional test vehicle had been designed, based on a PCB with 24 SOIC14 packages, assembled using range of techniques, to enable testing for short circuits between adjacent leads on individual component.

Other viable mitigation practices were hot-dip tinning for structural steel parts, or hot-oil fused tin plating. One observation was that failure predominantly occurred at the edges of plates, where full coating thickness was not geix around the right angle bend, and this geometry was a characteristic feature of component leads.


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He went on to discuss the detail requirements of Levels 2B, 2C and 3, with particular reference to the use of conformal coatings to form a physical barrier. Gia behalf of ESA, a working group led by Dr Dunn had produced a comprehensive set of guidelines for creating a lead-free control plan, which described the problems, requirements and methods relevant to the preparation of a plan for companies to control against the use of lead-free components and to ensure that pure tin did not find its way into the manufacturing chain.

This Standard establishes processes for documenting the mitigating steps taken hhb reduce the harmful effects of tin finishes in electronic systems. Trends for Printing Ultra Egia Chips. Standards Subscriptions from ANSI provides a money-saving, multi-user solution for accessing standards.

Pulse plating could be used as a means of manipulating the grain structure and orientation of the tin deposit, and in some instances showed reduced whisker growth compared with direct current deposits.

Since the introduction of the RoHS legislation inthe threat of tin-whisker-related short circuit failure from pure tin finished components has remained a major concern within the high-reliability electronics manufacturing industry. He showed several examples of actual failures, and other instances where whiskers had grown but not yet been detected electrically.

If the document is revised or amended, you will be notified by email. A whisker one micron in diameter could support a current of 10 mA. This paper presents a summary of efforts from document inception to document release.

In a recent SMT survey, we asked the following question: He began his presentation on problems associated with whisker growths with a remarkable time-lapse video recorded by researchers at Brown University, showing the initiation and growth of a tin whisker at a steady rate of about 1 micron per hour over a period of 40 hours.

Tin Whisker Mitigation Methodologies: Level 3 managed gea risks through complete avoidance. Engineers will need to “act like engineers” in order 0005 comprehend this information and apply it to their needs. Consequently, manufacturers of high-reliability electronics with RoHS exemption were left with no alternative but to manage tin-lead obsolescence by avoidance or mitigation.


The deposit characteristics studied were thickness, grain size, morphology, orientation, intermetallic formation and elemental diffusion effects, under varying conditions of temperature, humidity, thermal cycling and applied external stress.

It was intended to continue ageing the test vehicles and review failures after a further six months, and to visually inspect the assemblies again after twelve months, also to build control assemblies to investigate the geai of temperature during coating. Each batch of eight boards was delivered to consortium partners for coating and returned to NPL for testing. Dr Ashworth stressed that these observations related to the particular proprietary electroplating chemistry used in the study, and that other commercial formulations might demonstrate different relationships between current density, deposit geka and whisker growth.

This standard is applicable to Aerospace and High Performance electronic applications which procure equipment that may contain Pb-free tin finishes.

But how do we set about mitigating against such failure where the use of pure tin finished components is ggeia Summarizing at a high level, these challenges represent risks associated with 1 durability of the interconnection h 2 deleterious effects of tin whiskers.

A remarkable observation was that in some instances it could be several years before whiskers began to grow, depending on the substrate and stress level. Level 3, which was relevant to 005 designed to be sent into space, prohibited the use of pure tin finishes. As Pb-free technology increasingly becomes the standard for electronic interconnects and finishes, engineers must cope with the various challenges posed by this material.

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A proprietary bright tin plating process was used. But higher pulse frequencies could result in greatly accelerated whisker growth, which was believed to be favoured by fine grained columnar structures. Subscription pricing is determined by: