Two Forms of Experimental Simulation Analysis for Multiaxial Drilling Efforts in the Time Domain Model

Abstract

This study proposes an analysis of the machining efforts based on experimental strains results, in the time domain. We have developed the design and construction of two prototypes: a DP (Dynamic prototype) and a SP (Static prototype), which were submitted simultaneously to the same conditions of efforts produced during a full drilling operation with twist drill. Machining tools and electric resistive SGs (Strain gauges) were adapted in the tepped rotary shaft DP. In order to form electrical contacts in a dynamic way, a set of SR (Slip rings) was designed. A SP (Second prototype), developed for fixing the specimen, had a static shaft, without geometric variation, allowing a straightforward electrical connection with the SGs. The prototypes were adjusted to the center line of a radial drilling machine. The differentiated ways that SGs were arranged and interconnected to the WB (Wheatstone bridge) have established the condition, so that the DP only strains produced by twisting. In SP, on the other way, the SGs were adjusted in order to assimilate all the influence efforts influences produced during a machining process. The acquired analogic signal reproduced strains in both shafts, in a consistent way, with multi-axial loading patterns, which are satisfactorily related to the analytical results.