Individual Dissertation

Using research relating to consumer products, the difference in sound quality could clearly be heard between the metal comb used in the traditional products and a custom PLA comb designed in a 3D Printed Music Box. A fully 3D printed design would lack the authenticity of sound required to appeal to a wider audience therefore a metal comb was used which had 30 notes ranging from F3 to A6.

Initially, a rachet winding mechanism was investigated however due to the specifications of materials required, it had never been achieved using FDM 3D printing. Significant amounts of research and testing was conducted into this however it was not feasible within the time frame therefore, a manually hand-wound mechanism was created which used a series of 3 gears in a reduction ratio.

The barrel for the music box had a number of possible solutions however the pins had to be specifically considered as they are a weak point of this feature. Utilising the flexibility of FDM 3D prints, the music sheet could be printed flat to the bed and curved into the barrel using a series of guides and a threaded cap to hold it in place securely. Finite Element Analysis was carried out on the pins to ensure they were strong enough to withstand forces by the metal comb.

The software program was created using MATLAB and has a number of functions that aid usability. The user uploads, specifies start time and exports to convert their MIDI song into an STL file. This process uses a MATLAB Midi converter, an Excel spreadsheet to convert the notes into CAD data, and OpenSCAD to create a printable STL with minimal user input. This provided a 100% accurate conversion of song and was a very efficient way of solving the problem.