Effect of thermal treatment on the swelling and surface roughness of common alder and wych elm wood

Wood heat treatment has increased signifi- cantly in recent years and is still growing as an industrial process to improve some wood properties. We studied the change of swellingand surface roughness of common alder （Alnus glutinosa （L.） Gaertn. ssp.glutinosa） and wych elm （Ulmus glabra Huds.） woods after heat treatment at two different temperatures and durations. The temperatures were 180 and 200 ℃ and the durations were 2 and 4 h. A stylus method was employed to evaluate the surface char- acteristics of the samples. Roughness measurements by the stylus method were made in the direction perpendicular to the fiber on the wood surface. Four main roughness parameters, mean arithmetic deviation of profile （Ra）, mean peak-to-valley height （Rz）, root mean square roughness （Rq）, and maximum roughness （Ry） were used to evaluate the effect of heat treatment on the surface characteristics of the specimens. Swelling and surface roughness parameters （Ra, Rz, Ry, and Rq） differed significantly for two temper- atures and two durations of heat treatment. Swelling and surface roughness values decreased with increasing treat- ment temperature and treatment times.

Experimental investigation of cutting parameters in machining of 100Cr6 with tangential turn-milling method

The turn-milling methods for machining oper- ation have been developed to increase efficiency of con- ventional machines recently. These methods are used especially by coupling some apparatuses on the computer numerical control （CNC） machine to decrease the pro- duction time and machine costs, ensure the maximum production and increase the quality of machining. In this study, 100Cr6 bearing steel extensively used in industry has been machined by tangential turn-milling method. This paper presents an approach for optimization of the effects of the cutting parameters including cutter speed, workpiece speed, axial feed rate, and depth of cut on the surface roughness in the machining of 100Cr6 steel with tangential turn-milling method by using genetic algorithm （GA）. Tangential turning-milling method has been determined to have optimum effects of cutting parameters on the machining of 100Cr6 steel. The experimental results show that the surface roughness quality is close to that of grinding process.

Surface Roughness Simulation During Rotational-Magnetorheological Finishing of Poppet Valve Profiles

Surface finishing is essential for various applications in the aerospace industry.One of the applications is the poppet valve,which is used for leak-proof sealing of high-pressure gases in aerospace gas propulsion engines.The combustion engine also typically employs a poppet valve as an intake and exhaust valve.Nano-finishing a poppet valve is difficult because of its complex narrow profile.The precise nano-finished poppet valve perfectly fits on its seat and reduces hydrocarbon emissions.The rotational-magnetorheological fluid-based finishing process can be used effectively for these complicated surfaces.The polishing agent in this process is magnetorheological fluid,and rheological properties are controlled by a permanent magnet.This article presents the uniform finishing of the poppet valve's narrow ridge profile,which is analyzed through finite element analysis(FEA),wherein the outcomes are uniform shear stress,normal stress,and magnetic flux density distributions along the poppet ridge profile.The study of forces exerting on abrasive grains and surface roughness simulation is also conducted using FEA findings.The experiment is subsequently performed to verify the simulation results for poppet profile polishing.The obtained experimental and simulated surface roughness values are comparable.After the finishing process,the maximum percentage improvement of surface roughness is obtained as 93.71%.The rotational-magnetorheological fluid-based finishing process has high accuracy and reliability for specific applications.