Let there be Light!

;

Overview

Client profile –  Design Agency working with multinational global clients.

Description of the advance in science or technology that was being sought

We sought to manufacture a PCB Prototype and develop procedures and techniques to produce a low cost solar lighting product. We had to produce a product design which had a very limited form factor (space constraints) with the inclusion of added functionality in conjunction with a Li ion battery pack, powered by a small fragile solar cell powering specialised LEDs. We needed to identify areas on the PCB Design which could be improved to reduce the subsequent volume manufacture cost, build times and ensure product manufacture viability.

List of the scientific or technological uncertainties faced

Specific functionality requirements were required to help differentiate the product from what was currently available in the market. These needed to be incorporated into the design that added significant complexity to the build and therefore cost.  This was unacceptable for a low- cost model  for 3rd World countries (designated markets) so we were required to find the best combination of components to provide the lowest cost at the best functionality.
  • Could we identify suitable alternative components that were functionally compatible with the prototypes, and therefore reduce the cost?
  • How could we identity the areas of the PCB that we needed to improve upon to reduce built time?
  • Could we develop manufacturing and subsequent box assembly techniques efficiently to keep costs down?
  • Could we complete the complex sandwich build with tight tolerance mechanical constraints for the box assembly?
  • How could we eliminate components with mismatching footprints?
  • Could we overcome the reflow issues with certain semiconductors causing intermittent operation or failure?
  • Could we determine why and how to prevent reoccurrence of the units exploding?

Description of work carried out in order to resolve the uncertainties

Having manufactured some initial protypes which we subsequently tested for performance, we embarked on a cost reduction and efficiency program to reduce the cost of manufacture and improve yields.

Various alternative components were sourced, including a variety of capacitors and lower cost alternative connectors and assembled and tested. These were checked for electrical performance mechanical fit and suitability for the pre designed enclosure that they had to fit in.

Special handling techniques were developed for handling the solar panels during modification (these were fragile off the shelf units which had to be made suitable for the project . We found that standard handling methods resulted in pads and tracks being torn off the flimsy crystalline solar panel base material.

Procedures and techniques were developed to facilitate streamlined low-cost volume manufacture. These included the handling methods for the solar panels, hybrid manufacture of the electronics to include partial hand placement of some surface mount components where a much higher degree of accuracy was required than by the allowable tolerances of machine placement.