Microcasting is one of the significant technologies for the production of metallic micro parts with high aspect ratio(ratio of flow length to diameter).A micro precision casting technology based on investment casting ...Microcasting is one of the significant technologies for the production of metallic micro parts with high aspect ratio(ratio of flow length to diameter).A micro precision casting technology based on investment casting using centrifugal method was investigated.The micro parts of Zn-4%Al alloy with an aspect ratio up to 200 was produced at the centrifugal speed of 1 500 r/min and the mold temperature of 270℃.The investigations on the relationship between flow length and rotational speed were carried out. For microcasting,the flow length is not only dependent on the centrifugal speed under the constant centrifugal radius,but also on the preheating temperature of mold.The flow length increases as the rotational speed and the mold temperature increase,and is much higher at a mold temperature of 270 ℃thanat other mold temperatures.展开更多
The effects of sintering temperature on the surface roughness of gypsum bonded investments were investigated to find the appropriate sintering temperature applied for micro-investment casting.The surface roughness tes...The effects of sintering temperature on the surface roughness of gypsum bonded investments were investigated to find the appropriate sintering temperature applied for micro-investment casting.The surface roughness tests were carried out at sintering temperatures ranging from room temperature to 1,000 ℃ for investment compounds mixed from calcium sulphate α-hemihydrate and quartz powder (wt.%, 6:4; 5:5, 4:6, 3:7).In this experiment, each investment compound was prepared by pouring the investment materials into a plastic bottle with the good surface roughness (Ra～0.2 μm).DTA-TG curves were measured using a thermal analyzer to investigate the difference of surface roughness at different temperatures.The results show that the surface roughness of gypsum bonded investment is temperature sensitive.The preheating temperature of the mold should be up to 600 ℃, but not over 700 ℃, and the investment compound with 60 % plaster and 40 % quartz powder is applicable for preparing the micro-structures.The micro-structures with 100 μm diameter were produced in the present studies.The results show that the surface roughness of the casting is only Ra～0.51 μm, slightly rougher than that of the investment mold.展开更多
文摘Microcasting is one of the significant technologies for the production of metallic micro parts with high aspect ratio(ratio of flow length to diameter).A micro precision casting technology based on investment casting using centrifugal method was investigated.The micro parts of Zn-4%Al alloy with an aspect ratio up to 200 was produced at the centrifugal speed of 1 500 r/min and the mold temperature of 270℃.The investigations on the relationship between flow length and rotational speed were carried out. For microcasting,the flow length is not only dependent on the centrifugal speed under the constant centrifugal radius,but also on the preheating temperature of mold.The flow length increases as the rotational speed and the mold temperature increase,and is much higher at a mold temperature of 270 ℃thanat other mold temperatures.
基金supported by the National Natural Sicience Foundation of China (No.50475028)the Natural Science Foundation of Heilongjiang Province of China (No.ZJG04-01)
文摘The effects of sintering temperature on the surface roughness of gypsum bonded investments were investigated to find the appropriate sintering temperature applied for micro-investment casting.The surface roughness tests were carried out at sintering temperatures ranging from room temperature to 1,000 ℃ for investment compounds mixed from calcium sulphate α-hemihydrate and quartz powder (wt.%, 6:4; 5:5, 4:6, 3:7).In this experiment, each investment compound was prepared by pouring the investment materials into a plastic bottle with the good surface roughness (Ra～0.2 μm).DTA-TG curves were measured using a thermal analyzer to investigate the difference of surface roughness at different temperatures.The results show that the surface roughness of gypsum bonded investment is temperature sensitive.The preheating temperature of the mold should be up to 600 ℃, but not over 700 ℃, and the investment compound with 60 % plaster and 40 % quartz powder is applicable for preparing the micro-structures.The micro-structures with 100 μm diameter were produced in the present studies.The results show that the surface roughness of the casting is only Ra～0.51 μm, slightly rougher than that of the investment mold.
