Packaging considerations for Small Form Factor boards
Demanding environments require stalwart packaging even for the most rugged of boards.
Electronic equipment requires effective packaging solutions to prevent critical electronic components from overheating and to ensure consistent performance in demanding industrial environments. Therefore, design engineers must consider many diverse factors when choosing a packaging solution.
As the electronics industry increasingly focuses on flexibility, performance expectations, and design considerations, we are seeing several market trends:
Virtually every industry, not least of all electronics, is seeing components getting smaller. To use a healthcare example, a patient may have had to go to a specific room for a procedure. Now, however, with the shrinking of machinery and components, a mobile or handheld device may be used in the patient’s own room, thereby providing a more efficient outcome.
In the electronics industry, many manufacturers are transitioning from larger 19-inch systems to Small Form Factor (SFF), single-board computing. This shift requires a flexible packaging solution that can accommodate SFF printed electronics, including Single Board Computers (SBCs), Computers-On-Module (COMs), nanoETXexpress, Mini-ITX, and Nano-ITX.
Suppliers are introducing innovative electronic solutions with advanced capabilities at a rapid pace. As lifecycles for electronics continue to shrink, engineers must design efficiently to maximize the return on total-cost-of-design and cost-of-ownership investments. For instance, only a few years ago, an electronic communications system would be deployed in the field for an average of five or more years before it was replaced with an upgraded model. Now, however, with increasing technological advancements, an updated (next-generation) solution with the latest and greatest technology and features is typically released each year, dramatically shortening the lifecycle of a product. Thus, in this case, there are two options: Either deploy “future-proof” systems that may be updated as technology and application trends change, or replace with entirely new equipment.
Lifecycle reduction also forces the customer to consider the Total Cost of Ownership (TCO) of a product, which includes the initial cost to deploy, maintenance during the operational lifespan, and how long the solution will last. A key component to ensuring a cost-effective, future-proof, electronic solution includes the enclosure. For example, consider two enclosures that are priced competitively: Enclosure A is initially a low-cost solution but requires a complex and lengthy assembly time and significant investments in engineering and modification costs throughout the lifecycle. Enclosure B is offered at a slightly higher initial cost, but is based on a configurable platform that may be modified or reconfigured in accordance with changing requirements during the lifecycle at a minimal cost, and is assembled in two quick steps to help reduce assembly time and costs. Even if Enclosure B has a higher initial cost, the design engineer and assembly team save significantly in product lifecycle and labor costs, which may ultimately result in a better ROI.
Industrial OEMs are seeking ways to accomplish greater productivity by minimizing the quantity or excess of resources. By employing a cost-effective solution that offers multiple functionalities, such as electromagnetic shielding, thermal management, interconnectivity, and the like, design engineers can save significantly because they don’t have to purchase multiple pieces of equipment or components.
The electronics industry is also moving toward a trend of not having to worry about the details of the mechanics of a solution; it should work well and accommodate diverse application requirements. Design engineers expect manufacturers to stay on top of trends and technology, and to continually incorporate these advancements in their products. Additionally, OEMs expect a product to fit their application needs. While a product may have similar features and functionality year over year, it should also have some differentiation and flexibility to fit a user’s exact need.
When selecting an enclosure or case for sensitive electronic components, the following factors should be considered:
Easy and fast assembly and disassembly of an enclosure or case is important, as it directly impacts productivity. If an enclosure takes a significant amount of time to put together, this can result in a halt in operations, which in turn affects a company’s bottom line (Figure 1).
The enclosure or case should also provide quick access to the Printed Circuit Board (PCB), allowing for fast equipment service and maintenance, upgrades, solution of technical issues, and/or component replacement. Easy and quick access to the PCB is also critical to the product’s lifecycle. For example, in medical applications, equipment may need to be tested for proper calibration and performance. If the enclosure or case does not provide immediate access, this will slow testing procedures and may result in a delay of operations.
With today’s equipment running at higher frequency and generating increased power, the need to shield components from Electromagnetic Interference (EMI) is critical. Design engineers need components that do not interfere with other electronics, in addition to ensuring that the enclosure itself does not radiate interference.
To address these needs, enclosures with built-in Electromagnetic Compatibility (EMC) shielding save time and ensure continuous operation. While gasket solutions can also be used, these require additional assembly, separate ordering, and the risk of lost or misplaced components, as gaskets are very small. Employing an enclosure with built-in EMC shielding offers more convenience and minimizes the purchasing decision (Figure 2).
Enclosures with multiple equipment components residing inside will naturally generate increased heat, which means that effective cooling solutions must be implemented. Tests should be performed to identify the EMC shielding and cooling capabilities required for optimal performance.
The location of the heat source and the size of the enclosure greatly affects the EMC shielding and cooling requirements. For example, if an enclosure measures 1U high and 19 inches wide and is populated with equipment, it may be able to achieve as much as 26 Cubic Feet per Minute (CFM) with a standard fan bank running on high in a push-cooling configuration. Cooling requirements vary significantly from application to application, making it important to test separately for each one.
In addition to testing for EMC shielding and cooling capabilities, design engineers should consider enclosure accessories to help reduce integration time. These accessories may include:
- Board fixing, such as a mounting plate, flexible rail system, studs, self-adhesive support pads
- Mounting feet, including plastic feet, feet with tip-up function, and stacking feet
- Snap-on fan fixings or fan mounts for heat dissipation
- Enclosure mounting
- Digital assets, such as test reports, STEP 3D files, and user manuals
Depending on the application, enclosure or case customization may be required to either accommodate a corporate identity or fit a specific application need. For example, instead of having perforations on the side, top-to-bottom cooling may be better suited for a particular project. Custom accessories can include sizing, solid or perforated side panels, PCB mounting, ventilation, and mounting feet (Figure 3).
Applying the technology
Flexible packaging for electronic modems
While flexible enclosure solutions can be applied in virtually any industry, manufacturers of sensitive electronics especially appreciate flexibility. For example, critical electronics – such as two-way satellite time and frequency transfer modems – need an enclosure solution to effectively protect and cool the components to ensure continuous operation. However, the electronic components may differ in size and shape, requiring a flexible protection solution.
To satisfy this challenge, the manufacturer can employ a flexible enclosure with varying standard sizes that can be modified to specific application requirements. To provide the necessary cooling capabilities, the enclosure should also offer built-in EMC protection, eliminating the risk of interference without added effort or cost.
Customized packaging for audio/video cases
Audio/video cases require extensive customization due to the high quantity of cutouts and flexible design. For instance, when considering a specific case, the case may require multiple customization options, including:
- Design: The front of the case has a large cutout for a specific plug-in module, which will be covered by an additional panel screwed onto the case.
- Height: Since the case will be mounted on gliding channels, the height of the case must be adjusted to accommodate the additional size.
- Cutouts: The back panel will be used for cutouts and printing, which the taps will interfere with. Instead of a standard four-part version, a three-part version will be used where the back panel is slightly redesigned. The taps will be screwed on the top of the case in place of the back panel, ensuring the flexibility of the removable back panel and a stable and fixed front panel.
- Perforation: The side of the case has a special perforation for the cooling fan.
- Studs: To accommodate cost-effective, large production runs, the inside of the case will house various studs.
As described, this type of enclosure is significantly different from a standard case, providing a completely modular platform solution.
With industry trends constantly changing, it is critical that enclosures accommodate market expectations and diverse application requirements. By employing an enclosure with versatile sizing and accessories and increased modification options, design engineers can effectively protect their critical electronics with a highly versatile enclosure solution.
Pentair Electronics Protection Schroff