Based on decades of experience collaborating with customers, we frequently perform multiple reviews where the board design is overlayed into the enclosure CAD model. We do this frequently to track and validate form, fit and function. Depending upon your PC board design tools, we can accept various files you export. The import and export procedure between your board layout application may vary with SolidWorks, which we use. We begin by determining if 3D data can be acceptably translated. As a fallback, we can use a .dxf exported from your CAD package.
It is important for emissions and immunity that there be coordination between the enclosure design and connector selection and placement on the board. For instance, connector manufacturers like Tyco, Molex, FCI, etc., will provide a board layout document for holes or pads placement. Component manufacturers often define this placement with a distance to edge of board. This distance to edge of board is often incorrect for many connectors such as RJ, SFP, XFP, the list goes on. When using the “recommended” distance to edge of board, we frequently find connectors with grounding spring fingers or EMI gasketed flanges do not make proper contact with the chassis (or no contact at all). This can impact EMC and ESD compliance.
We solve this through collaboration with your PC board designer. You tell us the order in which components need to appear and we determine exact placement. Then we provide a drawing and CAD files with exact hole, pad or component placement. Later, once your board designer has placed the component and is preparing to route the board, we will have him or her feed back to us and IDF, STEP or DXF file for a double check. We import the data from your CAD tool’s export back into our enclosure design and look for issues so they may be immediately resolved. Sometimes it’s a correction to the board while other times it’s easier to change the enclosure design. As you can tell, this process provides for concurrent engineering of both PC boards and the enclosure with attention paid to thermal, safety, emissions and immunity.
Another thing we look at during this process is do we have enough space between connector, LED, switch components for placing intuitive and legible text for user identification? This will often times push connectors, LEDs, etc., to the left or right.
You may anticipate that we’ll want a conversation with your board layout designer to discuss where locations of greater heat dissipation will be. Once we understand higher watt density areas, we can turn our attention to airflow. We may ask if there is a possibility to adjust the placement of some components to minimize too much heat concentration in one area or to put components in an increased airflow path. We fully understand that these kinds of requests may not always be accommodated. Either way, we will be considering intake and exhaust and airflow volume. Next, do we need to add cooling techniques such as air compression, redirection, funneling, etc. As a side note, we might suggest placing hot component on the bottom of the board where we may use the enclosure as a heat sink and heat spreader. The bottom line is, we will consider multiple means to inexpensively cool your product before resorting to more expensive techniques such as heat pipes.