PRODUCT DESIGN CASE STUDY:

AUTOMATIC SKEW FOR SATELLITE SYSTEM

BRIEF

This project was completed for a well established global name within the leisure and touring vehicle market, specialising in products for TV and entertainment 'on the move'. The brief was to introduce automatic LNB rotation (known as Skew) to their existing fully automatic, roof mounted satellite systems. Automatic rotation of the LNB maximises satellite signal and allows customers to receive their native TV channels even further from home.

A electronics company would be responsible for the PCB development, enabling the system to look up the required skew angle, based on geographic position and desired satellite. The specific brief would therefore require a housing and mechanism which would work with the PCB to rotate the LNB. We would achieve the rotation using a pulley and belt assembly which would rotate a collar surrounding the LNB.

DESIGN & PROTOTYPING

In order to ensure product longevity and a maintenance free product life, all components were fully enclosed within a plastic enclosure. This would protect the PCB and all moving parts from the elements. Because the position of the LNB relative to the satellite dish is critical, a simplified enclosure would first be created to position the LNB and verify its position.

Internal components then went through various iterations in order to provide the necessary function. This involved several 3D printed prototypes which could be used to evaluate and further improve the design. Once these components were laid out in the assembly, further work was completed to improve the aesthetics, adding various details to improve the appearance and help the enclosure appear sleek and unobtrusive in the overall design.

Parts were designed for mass production, specifically injection moulding. This would mean that after initial tooling investment, they can be produced in large quantities. Because of the outdoor use environment, parts would be manufactured in ASA, a durable plastic material similar to ABS however exhibiting much better UV stability. Parts must be designed to suit the injection moulding process; this would be considered from an early stage in the design process to ensure part product is feasible when ready for production.

TESTING

Testing was completed throughout the design process and categorised into the following:

Performance Testing
Environmental Testing
Product Life and Wear Testing

Test procedures were put in place for each of the above along with a pass criteria. This testing would be completed in both lab conditions and in 'real life' use scenarios . At each stage of the design process testing would be repeated to ensure the design was reliable. Towards the end of the project when trial injection moulded parts were available, accelerated product life and wear tests took place to verify the product would perform correctly through its product life.

Misuse scenarios (such as close proximity jet washing the enclosure) would also be completed to learn if and how the product may fail when misused. This allowed these risks to be further mitigated before introduction to market.

MASS PRODUCTION

Prior to part sign off, they will be sent to an injection moulder who will complete a full tooling review. Assuming the parts have been designed to suit the injection moulding process, this should highlight minimal changes. Discussion with the injection moulders will agree important tooling details such as number of tool inserts,cavities, injection points, ejector pin positions, split lines and critical fit faces. All details will be added to the general arrangement drawing for each part, ensuring tool makers and machine operators are fully aware of design intent critical fits, dimensions and tolerances. Parts and drawings are now ready for sign off.

Tooling manufacture usually takes around 30-40 days; once completed parts will be trialled and reviewed. Finally, mass production can begin

Finished satellite system with full enclosed automatic skew enclosure

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