Design of an innovative flush hinge mechanism for cosmetic compact cases

Abstract

The cosmetic makeup industry considers aesthetics of their packaging of utmost importance as this forms part of the overall product they deliver to the end customer. With this in mind, Toly (Malta) Ltd, expressed the need to develop an innovative hinge mechanism for cosmetic packaging, since current compact cases all convey a disruptive look at the back of the compact and leaves much to be desired in terms of aesthetics. Therefore, the scope of this project was to design an innovative hinge mechanism that provides a clean flush look at the back of the compact via the application of engineering principles. The solution for the innovative flush hinge mechanism had to ensure a clean and premium look for the compact or palette, whilst any brought-in components such as pins or metal springs were eliminated to reduce costs and increase sustainability. Initially, a total of fourteen patents and existing hinge mechanisms were critically reviewed to gain scientific knowledge on the subject, which also helped to generate innovative flush hinge concepts. Following the Pahl and Beitz design process model, the task was first clarified and the main problems with the current hinge mechanisms for a disruptive look at the back of the compact, were outlined. The Avignon compact case produced by Toly was used as a Case study for this project. Four innovative hinge concepts were then devised via engineering methods such as SCAMPER and a morphological chart. The most promising flush hinge concept was then chosen via a decision matrix, to be later developed into a series of four prototypes in the embodiment stage. This stage involved a corrective process which carried out analysis, synthesis, simulation, and evaluation of each of the 3D printed prototypes, until a preliminary design was deemed to meet all product requirements. The final stage, the detailed design stage, first included the FMEA, from which a number of potential failure modes were observed which were then addressed in the material selection stage. The DFMA exercise was carried out and after following Boothroyd’s design guidelines to improve manufacturability and assembly times, it was estimated that the tooling costs increased, however, compensated by savings in material and assembly costs. Simulation analysis such as FEA and Moldflow were also carried out for a detailed analysis on the final design solution. Finally, the proposed solution was explained in detail and further work was suggested. The solution for an innovative FHM was successfully developed on the Avignon compact which meets all project aims and objectives.