Procedure

VN

Overview

This document provides data regarding the technical background and describes a procurement guidance, engineering procedures and guidelines to assist organizations reworking/repairing aerospace, defence and high performance electronic systems, whether they were assembled or previously reworked/repaired using traditional alloys such as SnPb or lead-free alloys, or a combination of SnPb and lead-free solders and surface finishes. This document contains an overview of known impacts and issues, processes for rework/repair, and provides technical rules to allow the repair technicians to execute their task. This document focuses on the removal and replacement of components. For the purposes of this document, the term "rework/repair" is used as applicable. This document can be used for high-performance and high-reliability systems by other industries at their discretion. The global transition to lead-free electronics affects the aerospace, defence and high performance (ADHP) industry and other industries for high reliability applications. This document is intended to facilitate the development of methods and processes for rework/repair of aerospace, defence and high performance (ADHP) electronics systems. It contains sufficient information to support the processing of equipment/appliances that incorporate either SnPb- or lead-free solder alloys, SnPb- or lead-free components and printed circuit board finishes, or a combination of leaded and lead-free materials. This document is intended to be used by original equipment manufacturers (OEMs), contract manufacturers (CMs) and commercial depots. This document can also be used by personnel performing rework/repair at the Maintenance Level "O" (Organizational Level), Workshop Maintenance Level "I" (Intermediate Level) and Maintenance Level "D" (Depot Level). Directives and Legislations issued by countries around the world enacted the stop of use of lead and other hazardous material usage in sectors of the electronics industry by 2006. In electronics, lead (Pb) has been a primary component in tin-lead (SnPb) solders used for the attachment of components and in printed circuit boards finishes for over 50 years, and more recently in the solder spheres for the attachment of ball grid array (BGA) packages. Since there is no "drop-in" replacement for SnPb solder alloys, numerous lead-free replacement alloys have emerged in the manufacturing industry. These diverse replacement alloys are used in printed circuit boards finishes, component termination finishes and as solder alloys, leaving the rework/repair technician with literally hundreds of possible metallic compounds during repair. The majority of the lead-free alloys that come into question have melting temperatures which are 34 °C to 44 °C higher than those of SnPb eutectic solder. With lead-free alloys, these higher processing temperatures require significant changes of convective rework/repair procedures and minor adjustments of conductive hand soldering procedures to ensure that quality products will be produced. The responsible committee is DKE/K 684 "Process Management for Avionics" of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.

Responsible national committee

DKE/K 682 - Aufbau- und Verbindungstechnik für elektronische Baugruppen