抄録
Cutting force and surface roughness are decreased by a thin coating of dilute carboxylic acid whose number of carbon is more than 7. It is presumed that these phenomena are caused by the chemisorption of organic polarity substance molecules to Al atoms near by the dislocation. In this experiment, the coating materials are liquid paraffin containing 0.2mass% carboxylic acid (C 8H 16O 2, C 10H 20O 2 and C 14H28O 2) or various kinds of 0.2mass% organic polarity substances whose number of carbon is 18. Cutting surface temperature Tis controlled between 15 to 60°C by Peltier thermo module elements. Cutting speed and depth are 1.67mm/s and 0.05mm, respectively. The following results were obtained. 1) Cutting force (F T max and F N max) and surface roughness Ry are decreased by the coating of carboxylic acid at the cutting surface temperature under the acid's melting point. 2) From the relation between ln(Frmax) and 1/T, activation energy is calculated at 120 to 200kJ/mol at the effective surface temperature for each acid. These values correspond to the formation energy of chemisorption between carboxylic acid molecules and Al atoms. 3)In the case of organic polarity substances except for carboxylic acid, these coating effects are not observed at the substance's melting point.
