Estudo da vida de ferramentas de corte em processos de usinagem através de modelos de confiabilidade

Abstract

The life of cutting tool has influence on the final costs of the product machined in the process of machining. Thus, it is fundamental to have criteria to define the survival of the tool so that it can be replaced or re-fired before it fails. influence the quality of the part. There are several statistical models that are used in the time until failure occurs. Therefore, for the analysis of tool life it was compared the maximum likelihood method in relation to the most used method that is Ordinary Least Squares, in order to show the advantages and disadvantages of disadvantages when using each method. After the process analyzes, the combination of factors that maximize the TTF of the tool are: for feed (f) = 0.38, for rotation (rpm) = 235 and square geometry, the two methods came to the same conclusion. The Maximum Method Likelihood has presented advantages with greater relevance, since it is able to obtain information for tool life analysis. In the present study, estimated the reliability of the tool for a survival of 1000 mm and was estimated to survival rates for 5% and 50% reliabilities, for all combinations between levels of advancement, rotation and geometry.