Product Design Scotland, Edinburgh: Shore Design

Hay Systems Ltd (HSL), an independent mobile network operator, infrastructure vendor and provider of global mobile services was developing their own 2.75G Femtocell device for both residential and office environments. However during the development they were faced with a number of challenging issues due to the design of their plastics enclosure. The main issues were:

• Thermally unstable device which quickly overheated
• Poor quality enclosure structure
• Expensive injection mould tooling investment costs
• Poor light guide performance

To help resolve these inherent issues the team at HSL turned to Shore Design.

Development

Our initial approach was to carry out a thorough investigation into the thermal performance of the enclosure. A test rig enclosure was designed in 3D CAD then manufactured in-house using our rapid prototyping facility. The test rig was designed using our extensive experience in thermal design and gave us the flexibility to test various air vent and fan solutions and the thermal data recorded and benchmarked against the original enclosure design. From the data we were able to optimise the ideal thermal solution for the product.

Following successful resolution of the thermal issues the Shore team then turned their attention to the various enclosure design issues. A new and improved light guide arrangement was designed and developed, again using our experience in this field in conjunction with extensive use of physical models and experimentation. In parallel the Design for Assembly and Design for Manufacture aspects of the component parts were improved to maximise the value of each part.

Result

Whilst the new design was sensitive to the inherited aesthetic design intent, the entire mechanical structure was re-created by Shore from scratch. This new enclosure design delivered significantly better cooling, improved light guide performance and solid build quality.

Additionally tooling investment costs were reduced by 50%, which in itself more than covered Shore's fees. Consequently the component part costs were also greatly reduced.

Shore were also able to leave the PCB layout design unchanged as it had already gone through extensive testing which meant a major development saving for HSL. ESD performance was improved and surpassed the CE requirements whilst the UL fire enclosure rating for the device was vastly increased.