Trends in modern industry show a tendency towards demassovization of production as a response to the customers＇ specific needs for unique and personalized products. This provokes significant changes in the processes ...Trends in modern industry show a tendency towards demassovization of production as a response to the customers＇ specific needs for unique and personalized products. This provokes significant changes in the processes of manufacturing, assembly, and testing The cost of such a type of production can be reduced by employing highly productive reconfigurable equipment with proper software to enable optimization. This paper presents a decision support extension for directing of hydraulic cylinders to assembly-testing lines using fuzzy logic in the Enterprise Resource Planning system of a small size production in a factory in Bulgaria. Different assembly-testing lines are flexibly assigned to the specific cylinder＇s parameters by the developed fuzzy system on the basis of the overlapping of parameters in the hydraulic cylinders classification. The final decision on the line assigned in case of alternatives is made through accounting for the minimal cylinder delay time. The effectiveness of the approach is assessed by simulation. It leads to an increase of the efficiency of the assembly-testing flow lines, a reduction of the time needed for hydraulic cylinders assembling and testing and balanced loading of the modules.展开更多
The running-in of cylinder liner-piston rings(CLPRs)is the most important process that must be performed before a marine diesel engine can be operated.The quality of running-in directly affects the reliability of a CL...The running-in of cylinder liner-piston rings(CLPRs)is the most important process that must be performed before a marine diesel engine can be operated.The quality of running-in directly affects the reliability of a CLPR.The surface texture of a CLPR has been proven to significantly affect its lubrication performance.In this study,the tribological behavior of a CLPR during running-in is investigated.Three types of surface textures are generated on the CLPR via laser processing:dimple texture on piston rings,groove texture on cylinder liners,and co-texture on both sides.Subsequently,a series of tests are performed on a slice tester.A load of 300 N(1.64 MPa) is applied,and two speeds(50 and 100 rpm)are adopted.The CLPR running-in quality is characterized based on three parameters,i.e.,the friction coefficient,contact resistance,and wear topography.Experimental results show that,compared with a non-textured surface,the three types of surface textures mentioned above improved the friction performance during running-in.The lubricant supply capacity of the dimple texture on the piston ring,as a mobile oil reservoir,is stronger than that of the groove texture on the cylinder liner serving as a static oil reservoir.By contrast,the wear resistance of the dimple texture,as a movable debris trap on the piston ring,is weaker than that of the groove texture on the cylinder liner,which serves as a static debris trap.It is demonstrated that the co-texture combines the advantages of dimples and groove textures.Compared with non-textured surfaces,the friction coefficient decreased the most at 100 rpm(44.5%),and the contact resistance improved the most at 50 rpm(352.9%).The coupling effect provides the surface with improved running-in quality by optimizing the tribological performance,particularly at the dead center.This study provides guidance for the tribological design and manufacturing of CLPR in marine diesel engines.展开更多
文摘Trends in modern industry show a tendency towards demassovization of production as a response to the customers＇ specific needs for unique and personalized products. This provokes significant changes in the processes of manufacturing, assembly, and testing The cost of such a type of production can be reduced by employing highly productive reconfigurable equipment with proper software to enable optimization. This paper presents a decision support extension for directing of hydraulic cylinders to assembly-testing lines using fuzzy logic in the Enterprise Resource Planning system of a small size production in a factory in Bulgaria. Different assembly-testing lines are flexibly assigned to the specific cylinder＇s parameters by the developed fuzzy system on the basis of the overlapping of parameters in the hydraulic cylinders classification. The final decision on the line assigned in case of alternatives is made through accounting for the minimal cylinder delay time. The effectiveness of the approach is assessed by simulation. It leads to an increase of the efficiency of the assembly-testing flow lines, a reduction of the time needed for hydraulic cylinders assembling and testing and balanced loading of the modules.
文摘The running-in of cylinder liner-piston rings(CLPRs)is the most important process that must be performed before a marine diesel engine can be operated.The quality of running-in directly affects the reliability of a CLPR.The surface texture of a CLPR has been proven to significantly affect its lubrication performance.In this study,the tribological behavior of a CLPR during running-in is investigated.Three types of surface textures are generated on the CLPR via laser processing:dimple texture on piston rings,groove texture on cylinder liners,and co-texture on both sides.Subsequently,a series of tests are performed on a slice tester.A load of 300 N(1.64 MPa) is applied,and two speeds(50 and 100 rpm)are adopted.The CLPR running-in quality is characterized based on three parameters,i.e.,the friction coefficient,contact resistance,and wear topography.Experimental results show that,compared with a non-textured surface,the three types of surface textures mentioned above improved the friction performance during running-in.The lubricant supply capacity of the dimple texture on the piston ring,as a mobile oil reservoir,is stronger than that of the groove texture on the cylinder liner serving as a static oil reservoir.By contrast,the wear resistance of the dimple texture,as a movable debris trap on the piston ring,is weaker than that of the groove texture on the cylinder liner,which serves as a static debris trap.It is demonstrated that the co-texture combines the advantages of dimples and groove textures.Compared with non-textured surfaces,the friction coefficient decreased the most at 100 rpm(44.5%),and the contact resistance improved the most at 50 rpm(352.9%).The coupling effect provides the surface with improved running-in quality by optimizing the tribological performance,particularly at the dead center.This study provides guidance for the tribological design and manufacturing of CLPR in marine diesel engines.
