Otimização do Pino-Fusível de um Equipamento de Quick-Stop para Torneamento

Abstract

The machining process consists of removing material from a workpiece to achieve the desired shape, dimensions, and/or surface finish. With the advancement of technologies and the creation of more efficient machines, the manufacture of more precise parts and components requires greater technology in machining and the study of each part that constitutes this process. One of the problems faced in this process is the difficulty of obtaining the chip in the same conditions as it presents when it is being removed from the workpiece, which impairs obtaining precise data and improving the process. To solve this problem, the Quick-Stop mechanism is used. This mechanism enables a shortening of the time between the cutting process stop and the chip removal, an abrupt stop, so that the removed chip remains in very close conditions to the chip during cutting, without altering the structure and other parameters. The Quick-Stop mechanism uses an actuator, which can be of various types, such as the explosive action of a detonator arranged in a firearm, pneumatic, and impact hammer. The fuse pin is used to ensure that the Quick-Stop is carried out correctly. The conditions imposed on the fuse pin must be close to ideal to ensure that the Quick-Stop is carried out correctly. The pin must be strong enough to withstand the forces of the cutting process but fragile enough to break upon impact with the Quick-Stop tool, and the stress concentration generated by its geometry is a problem to be solved. Therefore, the study of material, diameter, length, hardness, heat treatment and other parameters must converge to achieve perfect conditions. This work evaluated specific chamfer size conditions for the pins in search of the most suitable geometry for the process that generates sufficient stress concentration to withstand the cutting forces and break upon tool impact, in addition to the influence of heat treatment on the same. SOLIDWORKS® software was used to create the model of the Quick-Stop equipment together with ANSYS® software to carry out a computer simulation of the working conditions for each case evaluated. The optimized pin condition was a 1mm deep chamfer and it was determined that quenching with water cooling improved the process.