Search results

Polymer laser powder bed fusion (PBF-LB/P) is an additive manufacturing technology that is sustainable due to the possibility of recycling the powder multiple times and allowing the fabrication of gears without the aid of support structures and subsequent assembly. However, there are constraints in the process that negatively affect its adoption compared to other additive technologies such as material extrusion to produce gears. This study aims to demonstrate that it is possible to overcome the problems due to the physics of the process to produce accurate mechanism.

Technological aspects such as orientation, wheel-shaft thicknesses and degree of powder recycling were examined. Furthermore, the evolving tooth profile was considered as a design parameter to provide a manufacturability map of gear-based mechanisms.

Results show that there are some differences in the functioning of the gear depending on the type of powder used, 100% virgin or 50% virgin and 50% recycled for five cycles. The application of a groove on a gear produced with 100% virgin powder allows the mechanism to be easily unlocked regardless of the orientation and wheel-shaft thicknesses. The application of a specific evolutionary profile independent of the diameter of the reference circle on vertically oriented gears guarantees rotation continuity while preserving the functionality of the assembled mechanism.

In the literature, there are various studies on material aging and reuse in the PBF-LB/P process, mainly focused on the powder deterioration mechanism, powder fluidity, microstructure and mechanical properties of the parts and process parameters. This study, instead, was focused on the functioning of gears, which represent one of the applications in which this technology can have great success, by analyzing the two main effects that can compromise it: recycled powder and vertical orientation during construction.

Over some 20 years, the popularity of competitive bodybuilding has increased significantly in India, along with an increase in sponsorship and professionalism in the organisation of events. Multiple competitions are now held at city/town, state, and national levels, organised by a vast range of organisations. The popularity of the sport follows the arrival of muscular bodies in Indian cinema and the attendant rapid growth of the country’s fitness industry. However, what is required for a bodybuilding competition on-stage is not necessarily the same as what actors showcase in movie scenes, specifically orchestrated to underline bodily accomplishments. Nor may it be what clients are after when they enter a gym. This chapter examines how Indian bodybuilders who often make a living as personal trainers navigate different bodily ideals. It foregrounds the notion of ‘muscular capital’ to deepen the understanding of what value a bodybuilder’s body might hold on and off stage and how it is perceived by others. Building on extensive fieldwork in Chennai, Tamil Nadu, this chapter seeks to move beyond the mere economic dimensions of bodybuilding and instead gives prominence to the sociocultural aspects of the body as they reflect an array of different (post colonial) demands and expectations.