This paper presents a comparison of surface roughness between both ceramic cutting tools namely, TiN coated mixed ceramic CC6050 and uncoated mixed ceramic CC650 when machining hardened hot work steel X38CrMoV5-1 [AISI H11] treated at 50 HRC. A mathematical model, relating surface roughness criteria and main factors such as cutting radius, cutting speed, feed rate, and depth of cut, was developed using response surface methodology (RSM) and its adequacy was checked by regression analysis. The effect of cutting parameters on surface roughness is evaluated and the optimum cutting conditions to minimize the surface roughness are determined. A multiple linear models have been established between the cutting parameters and the surface roughness using response surface methodology. The experimental results reveal that the most significant machining parameter for surface roughness is the feed followed by cutting radius. Also the determined optimal conditions really reduce the surface roughness on the machining of AISI H11 steels within the ranges of parameters studied. In addition, excellent surface roughness was obtained in hard turning using CC650 tools. The coated ceramic tools had no advantage over CC650 from the point of view of surface roughness. Keywords Hard turning . AISI H11 steel . Ceramic . Surface roughness . ANOVA . RSM Nomenclature Vc Cutting speed (m/min) HRC Rockwell hardness f Feed rate (mm/rev) ANOVA Analysis of variance ap Depth of cut (mm) RSM Response surface methodology r Cutting radius (mm) DF Degrees of freedom Ra Arithmetic mean roughness (μm) Seq SS Sequential sum of squares Rt Total roughness (μm) Adj MS Adjusted mean squares Fc Tangential force (N) Cont. % Contribution ratio (%) HT Hard turning R² Coefficient of determination (%).
This study investigated the cutting performance of coated CC6050 and uncoated CC650 mixed ceramics in hard turning of hardened steel. The cutting performance was mainly evaluated by cutting force components and tool wear. The planning of experiments was based on Taguchi's L 36 orthogonal array. The response surface methodology and analysis of variance were used to check the validity of multiple linear regression models and to determine the significant parameter affecting the cutting force components. Tool wear progressions and, hence, tool life, different tool wear forms and wear mechanisms observed for tools coated with TiN and uncoated mixed ceramics are presented along with the images captured by digital and electron microscope. Experimental observations indicate higher tool life with uncoated ceramic tools, which shows encouraging potential of these tools to hard turning of AISI H11 (50 HRC). Finally, tool performance indices are based on units which characterise machined cutting force components and wear when hard turning.
Motorcycle drivers are considered among the most vulnerable road users, as attested by the number of crashes increasing every year. The significant part of the fatalities relates to “single vehicle” loss of control in bends. During this investigation, a system based on an instrumented multi-sensor platform and an algorithmic study was developed to accurately reconstruct motorcycle trajectories achieved when negotiating bends. This system is used by the French Gendarmerie in order to objectively evaluate and to examine the way riders take their bends in order to better train riders to adopt a safe trajectory and to improve road safety. Data required for the reconstruction are acquired using a motorcycle that has been fully instrumented (in VIROLO++ Project) with several redundant sensors (reference sensors and low-cost sensors) which measure the rider actions (roll, steering) and the motorcycle behavior (position, velocity, acceleration, odometry, heading, and attitude). The proposed solution allowed the reconstruction of motorcycle trajectories in bends with a high accuracy (equal to that of fixed point positioning). The developed algorithm will be used by the French Gendarmerie in order to objectively evaluate and examine the way riders negotiate bends. It will also be used for initial training and retraining in order to better train riders to learn and estimate a safe trajectory and to increase the safety, efficiency and comfort of motorcycle riders.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.