Electronics Protection - Spring 2015 - (Page 14)

Feature Identifying the Ideal Mechanical PCB Hardware for Electronic Systems Marc Caiola, Platform & Marketing Leader, North America Schroff, Pentair Mechanical Printed Circuit Board (PCB) hardware and retainers are an important component in any electronic subassembly or system, as they provide the required clamping force and placement to board module assemblies, electronic subracks or system chassis'. These essential mechanical components ensure complete PCB protection. To ensure optimal performance of the electronic system, the PCB must be supported and placed in correct alignment. If a board does not have a secure clamp, the board may not only fall out of alignment, but it may also start to flex, which can result in system failure or accidental ejection of the board. In addition to board protection and placement, retainers are ideal for thermal management with sensitive electronics. Retainers prevent wear and failure by transferring heat away from electronic components, while delivering higher retention force on the board. PCB handles, code keys, injectors and ejectors can provide a failsafe solution for ensuring proper board placement, insertion and extraction. With today's diverse electronic systems applications, a variety of PCB hardware and retainer solutions may be deployed to address a broad range of unique protection requirements. This article introduces different types of PCB hardware solutions and their applications. These range from general electronic systems requiring basic board retention and placement to complex high-tension, clamping force applications found in high shock and vibration environments, such as industrial and transportation applications. Types of Mechanical PCB Hardware With multiple styles available, correctly specified PCB hardware can provide a reliable protection solution for diverse applications. Examples include: injectors and ejectors, nylon and metallic card guides, PCB tainers, Card-Lok and Wedge-Lok board retainers, code keys and conduction-cooled assemblies. Injectors and Ejectors PCB injectors and ejectors are generally used in both sheet metal and cold wall applications to facilitate the installation and removal of standard PCBs with high-density backplane interconnects. Available in metal and plastic design, in addition to various lever styles and finishes, injectors and ejectors can be installed and removed in diverse applications. These components are levers, which are fitted to the PCB and are retained in front of the selected PCB guide. Injectors and ejectors are designed to ensure simple insertion and extraction of the PCB from a subrack, case or system chassis. Nylon and Metallic Card Guides Nylon and metallic card guides provide an economical and quick solution to effectively align and mount PCBs. With easy card insertion, these card guides firmly support and protect the board. Card guides are available with tough, electrically insulating nylon or metallic material. PCB-Tainers PCB-Tainers feature a spring-action card retention design and provide a low-cost board alignment and retention solution for sheet metal applications. PCB-Tainers are optimal for providing 14 Spring 2015 * www.ElectronicsProtectionMagazine.com protection against basic shock, vibration and unique grounding characteristics, often found in harsher environments. Card-Loks and Wedge-Loks Card-Lok and Wedge-Lok retainers are designed to secure PCBs to the cold wall in cold plate-heat exchanger Card-Lok and Wedge-Lok retainers applications. They are typiare designed to secure PCBs to the cally mounted to the board cold wall in cold plate-heat exchangor subrack. Providing retener applications. tion to the card guide, the Card-Lok retainer clamps to the board edge to ensure secure clamping at the connector side, top and bottom edges and backplane side. Advanced Card-Lok and Wedge-Lok retainers employ a screwactuated wedge action that locks the PCB in place with the use of a standard hex wrench, establishing the secure hold required for military two-level maintenance systems. Eliminating the need for a torque wrench, this design applies no insertion and extraction force on the PCB, removing the risk of over tightening to prevent damage to the board and Card-Lok during installation. Card-Lok retainers are available in various lengths, individual wedge dimensions, mounting configurations and finishes to satisfy diverse application requirements. Conduction Cooled Assemblies and Code Keys Conduction-cooled assemblies (CCAs) are generally used when passive free air convection or Metal card guides provide an economical active forced air cooling and quick solution to effectively align is not possible, such as and mount PCBs. in space applications, or where creating airflow with moving parts might affect the reliability of the system. Featuring a robust, lightweight aluminum design, CCAs deliver high thermal conductivity, while ensuring sufficient structural support. CCAs consist of a conduction-cooled frame, backing plate, extractors and wedge clamps. They are designed for PCBs requiring cooling in severe environments where convection cooling is not practical. CCAs are available in numerous configuration sizes and finishes to provide structural support in extremely high shock and vibration applications. CCAs may be configured for various platform and application requirements including but not limited to 3U or 6U VME, VPX, IEEE 1101.2 and VITA 30.1 applications. Code keys are attached to the PCB or CCA to mitigate the risk of inadvertent PCB insertion into an incorrect slot within the electronic assembly. Mechanical PCB Hardware and Retainer Applications Multiple retainer types are available to meet the unique needs of every application. Industrial Machinery In many industrial settings, continuous vibration poses a unique challenge to PCBs. Retainers are used to keep circuit boards in complete alignment and firmly positioned in their card slot. In ad- http://www.ElectronicsProtectionMagazine.com

Table of Contents for the Digital Edition of Electronics Protection - Spring 2015

Editor's Choice
Predictive Modeling: The Next Frontier in Data Center Condition Maintenance
Don't Forget the Batteries
Military Aircraft Power
Pumped Two Phase Cooling Solutions for Challenging Thermal Management Applications
Identifying the Ideal Mechanical PCB Hardware for Electronic Systems
Bridging the Technology Gap: The Importance of Cyber and Physical Security within the Data Center
Waterproof Mobile Device Protection without Compromising Acoustic Quality
Enclosures
Thermal
EMI/EMC/RFI
Power
Hardware
Contamination
Industry News

Electronics Protection - Spring 2015