Mechanical development - Enclosure design |
Mechanical development in an embedded project includes for example challenges like heat dissipation, EMC, shock/vibration and protection against humidity, dust and dirt according to the IP classification. It’s about enclosing and sufficiently protecting the computer board. Hectronic offers mechanical development as one of the elements in development projects of complete embedded systems. Additionally mechanical development services such as pre-studies and reviews are available to support our customers buying COTS products.
Let me share some brief examples to illustrate our experiences and competences from the area of mechanical development. |
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System to monitor and control an unmanned aircraft |
| The system was developed for Saab Aerosystems in Linköping, Sweden. One of the challenges in mechanical development was the strict requirements on EMC protection, internally as well as externally towards the surrounding environment. The system was developed according to the RTCA DO-254 aviation standard. |
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| The enclosure was milled out from a block of aluminum to ensure sufficient EMC protection. Each independent functional part of the computer board was provided with a compartment in the enclosure. A corresponding pattern of cupper strips on the board connects to the compartment walls upon assembly. The solution proves maximum protection against EMC. Additional requirements on the enclosure included robustness and water protection. Rubber gaskets were used to protect the electronics from water, dust and dirt. |
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Cost-effective plastic enclosure for easy assembly |
| The development project in this example included a full-custom embedded system. The computer board was based on an ARM processor. The enclosure needed to be low-cost and easy to assemble. Apart from that Hectronic mechanical engineers were free to make suggestions. |
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| The two halves of the plastic enclosure are held together by snap-locks. The computer board is placed between the two halves with openings to match the onboard connectors. |
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Heat spreader with air guides |
| The customer of the system development project made the design of the exterior of the enclosure. The original requirement didn’t include a fan for heat dissipation. The design was compact and slim and the processor platform power consumption was around 30W. A heat simulation indicated that passive cooling using only heat sink weren’t going to keep system temperatures low enough. |
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| The principal of heat dissipation in this case was to force the air from the inlets, past the hot spots on the board and to the outlets of the enclosure using a fan. The forced air stream may have a tendency to form a vortex inside the enclosure. To avoid a vortex keeping heat inside the enclosure the fan and heat sink were complemented with a plastic air guide. |
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