This paper introduces a new type machine for polyblends with excellent mixing capabilities of internal mixer and continuous molding character of extruder.The machine includes two functions - mixing and extrusion moldi...This paper introduces a new type machine for polyblends with excellent mixing capabilities of internal mixer and continuous molding character of extruder.The machine includes two functions - mixing and extrusion molding that have been composed together by rational design,so a tandem production mode - "batch + continuous" are opened up.The mathematical model of continuous mixing molding was established and verified availably by experimental research.The main physical mechanical property of vulcanizate,which had met national waterproof material standard,verified the machine practicability.The essential difference from other similar type machines is that this machine is not only suitable in producing granular and powder rubbers but also lumpish rubbers.展开更多
Powder mixed electric discharge machining(PMEDM)is one of the modern developments in electric discharge machining(EDM)process.In the present work,finite element modeling has been carried out considering randomly orien...Powder mixed electric discharge machining(PMEDM)is one of the modern developments in electric discharge machining(EDM)process.In the present work,finite element modeling has been carried out considering randomly oriented multiple sparks during PMEDM.Transient thermal analysis is done to obtain temperature distribution,volume removal,and proportion of volume removed by melting and evaporation at different current,pulse on time and fraction of heat that enters to work piece.Gradually growing spark behavior and Gaussian distribution of heat source is used to simulate multiple craters.Temperature distribution along radial direction shows peak temperature at center of spark and thereafter a gradual decrease with increase in radial distance.Along depth direction temperature sharply decreases that forms wider craters with shallow depth in PMEDM.Peak temperature and volume removal increases with current more rapidly.Volume removal by melting is much higher than evaporation at lower current settings and with higher current almost equal amount of material is removed by melting and evaporation thus reducing the re-solidification of melted material.Current plays a significant role behind the contribution of material removal by evaporation followed by fraction of heat.Increase in pulse on duration increases the total volume of material removal however does not significantly increase the proportion of volume removal by vaporization.展开更多
基金National Natural Science Foundation of China(No.50375075)
文摘This paper introduces a new type machine for polyblends with excellent mixing capabilities of internal mixer and continuous molding character of extruder.The machine includes two functions - mixing and extrusion molding that have been composed together by rational design,so a tandem production mode - "batch + continuous" are opened up.The mathematical model of continuous mixing molding was established and verified availably by experimental research.The main physical mechanical property of vulcanizate,which had met national waterproof material standard,verified the machine practicability.The essential difference from other similar type machines is that this machine is not only suitable in producing granular and powder rubbers but also lumpish rubbers.
文摘Powder mixed electric discharge machining(PMEDM)is one of the modern developments in electric discharge machining(EDM)process.In the present work,finite element modeling has been carried out considering randomly oriented multiple sparks during PMEDM.Transient thermal analysis is done to obtain temperature distribution,volume removal,and proportion of volume removed by melting and evaporation at different current,pulse on time and fraction of heat that enters to work piece.Gradually growing spark behavior and Gaussian distribution of heat source is used to simulate multiple craters.Temperature distribution along radial direction shows peak temperature at center of spark and thereafter a gradual decrease with increase in radial distance.Along depth direction temperature sharply decreases that forms wider craters with shallow depth in PMEDM.Peak temperature and volume removal increases with current more rapidly.Volume removal by melting is much higher than evaporation at lower current settings and with higher current almost equal amount of material is removed by melting and evaporation thus reducing the re-solidification of melted material.Current plays a significant role behind the contribution of material removal by evaporation followed by fraction of heat.Increase in pulse on duration increases the total volume of material removal however does not significantly increase the proportion of volume removal by vaporization.
