ANALYSIS OF MULTIPLE COMPARISONS TEST ON INFLUENCE OF CARBIDE TOOLS DRILLIN COATINGS AT THE CUTTING FORCE OF DRILLING COMPACTED GRAPHITE IRON
Deibe Valgas dos Santos1; Durval Uchôas Braga2; Elifas Levi da Silva3
1 Centro Universitário UNA; 2 2Universidade Federal de São João Del Rei/MG; 3 Centro Universitário de Formiga/MG
doi:10.20906/CPS/COB-2015-1498
Resumo
A common difficulty in science and mainly in the industry is to evaluate the various ways statistical approach to determine which eventually will produce a safe result, when the results of a design of experiments leads to rejection of the null hypothesis, indicates an affirmation that all average (treatments) are equal, therefore, there is evidence that the diverge significantly average between of the levels. The multiple comparison test (contrast) permit to identify the differences between specific pairs of averages or averages of the linear combinations. This research aimed to evaluate the influence of the helical carbide drills coatings on cutting forces in drilling cast iron vermicular (ASTM A 842/2004), which is used in building components for automotive engines with thinner inside walls than of the building Diesel engine blocks of cast iron. The input variables of this study was the feed rate of 26 mm / rev. and cutting speed of 90 m / min, and three helical carbide drills of 10 mm diameter with the same geometry and TiAlN and AlCrN + x, AlCrN + y coatings and the tests were realized with shaped cutting fluid spouted and dry, used three route with the drill feed of the 10, 20 and 30 mm. The process responses were torque value, thrust force. The planning of experiments followed the full factorial statistical model, spanning two levels for cutting fluid, and three levels for the coatings of tools and three levels for the length of advance of the drill, the experiments were performed with three replicas, was used the contrast method to check for statistical difference between the average of the torque moment and the route of the drills. As possible results, we stand out the cutting fluid influences the cutting forces represented by the torque value, and also the thrust force. For torque value, type of coating showed no statistically influence, however, the thrust force the coating being presented influence AlCrN + y drill that had the highest cutting forces.
Palavras-chave: cast iron vermicular; coating; drilling; Multiple Comparison Test