Influência da geometria e textura da ferramenta de aço rápido no microtorneamento do alumínio AA1100

Abstract

Due to demands by miniaturized products, the micro-turning is of great value to the manufacture of parts and the study in any branch of this area is always very welcome. The present study approaches the micro-turning of commercially pure aluminum with high speed steel tools. This work aims at a better preparation of the cutting edge of high-speed steel tool applying electrochemical machining after grinding. The advantages lie in the removal of burrs, texturing of the tools and the rounding of the cutting edges of the tools. The cutting parameters chosen for the micro-turning were the cutting speed of 270 m/min, 0.2 mm depth of cut, and feed of 0.05 mm/rev. For the electrochemical machining, the input parameters are: a current of 2 A, a direct continuous voltage of 20 V and attack time of 15 s for 40 g/l concentration of aqueous NaCl and attack time 25 s for 20 g/l concentration of NaCl in aqueous electrolyte. The output parameters analyzed were: roughness of the tool and the specimen, MEV of the surface of the tools, characterization of chemical elements by means of MEV-EDS, tool wear and chip thickness ratio. As a result it was observed that the tools that were submitted to electrochemical machining obtained worse results of surface finish on the specimen compared to the tools that were only sharpened by grinding. The electrolyte of 40 g/l aqueous NaCl with attack time of 15 s produced lower values of surface roughness that the tools processed with concentration of 20 g/l NaCl and attack time of 25 s. Among the ground tools, the tool with minor 𝛾𝑜 (10°) generated the best values of roughness on the specimen. In all the tested conditions, the wandering of continuous ribbon chips around the specimen, cutting tool, and mini-machine tool disturbed the roughness of the specimens. The tools presented adhesion of aluminum on the flank surfaces and rake surfaces in all passes.