Analysis and redesign of a glass fiber reinforced polyamide clutch pedal for additive manufacturing

Abstract

The engineering design process has always had limiting factors materializing ideas from its conception down to the physical world through manufacturing techniques. Each manufacturing technique, as injection moulding, has always added constraints and limiting factors to the creativity of the engineer design during the design phase. In the recent years, the rising of a new manufacturing technique with notorious design freedom, additive manufacturing (AM), has been in everyone’s lips. Since this technique has been progressively jumping into different kind of materials, the expectations have increased into its maximum exponent. Therefore, blind jumping into this technique is not a smart approach. This new design freedom does not cost for free. Until recent years, the achievable mechanical properties of parts made by AM have been quite poor in comparison to its similar classical fabrication approaches. Furthermore, it would not be in another way in the science of short fiber reinforced polymer composites. The rise of this disruptive technology is promising, but the long way ahead until the process is mastered and equalled in mechanical properties to other techniques cannot be denied. In any case, the new potential possibilities are really interesting, being AM the viable physical solution for topology optimization algorithms. The necessity of mastering the AM process, has arisen new simulations and FEM techniques in order to simulate and predict the best possible way the manufacturing process output. Some of these parameters are FEM model initial stresses and warpage, the fiber orientation, and non-isotropic material properties among others. After the simulation and structural analysis of a current part, a clutch pedal, made of SFRP composite and manufactured for injection moulding, has gone into a redesign for AM. This work deals with some of the previous commented parameters inherent to the AM process. These are the nozzle toolpath, the material micro-model and the printing initial stresses. Throughout new software capabilities, these features have been computed and added into structural FEA models. A final comparison between the different models for each technology has been conducted. Some discussions about its interpretation have been finally written down, defining a set of tips for further works such as the printing of the part itself. Ultimately, a great effort has been made not only in the technical aspects of the mechanical design for additive manufacturing, but also in its influence in the engineering design process and the new design methodologies that can arise thanks to this technology.