• Title/Summary/Keyword: Grinding Efficiency

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A Study on the Internal Grinding to Improving the Grinding Efficiency (내면연삭(內面硏削)의 가공능률향상(加工能率向上)에 관한 연구)

  • Kim, G.H.;Kang, J.H.;An, S.O.;Park, J.K.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.2 no.6
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    • pp.87-93
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    • 1994
  • This paper describes on the establishment of an optimal internal grinding conditions for the purpose of improving the grinding efficiency against to the high-speed grinding. Through the fundamental grinding tests for the brittle and hardened material, we are concluded that high-speed internal grinding is effective to improve the grinding accuracy as well as the grinding efficiency. The obtained results are as follows: (1) Under the speed ratio $(V_w/V_g)$ is constant, it is possible to increase the grinding efficiency with satifying the constraint conditions. (2) Increasing the wheel velocity, surface roughness and out-roundness are improved. (3) Under the wheel depth of cut is constant and increasing the speed ratio, workpiece residual stress is decreased. The described method, in this paper, is capable of determining the optimum internal grinding conditions taking into account some constraint conditions, and practical algorithm for optimum internal grinding conditions are presented.

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Wet Fine Grinding of Rice Husk Ash using a Stirred Ball Mill (교반 볼밀을 이용한 왕겨재의 습식 미세분쇄에 관한 연구)

  • Park, S.J.;Kim, M.H.;Choi, Y.K.
    • Journal of Biosystems Engineering
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    • v.31 no.1 s.114
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    • pp.33-38
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    • 2006
  • This work was conducted to find the operating characteristics of an efficient wet grinding system designed to obtain fine rice husk ash powder. Once the rice husk was combusted and the thermal energy was recovered from the furnace, the ash was fed and pulverized in the grinding system resulting a fine powder to be used as a supplementary adding material to the portland cement. Grinding time (15, 30, 45 min), impeller speed (250, 500, 750 rpm), and mixed ratio (6.7, 8.4, 11.l, 20.9) were three operating factors examined for the performance of a wet-type stirred ball mill grinding system. For the operating conditions employed, mean diameter of fine ash powder, specific energy input, and grinding energy efficiency were in the range of $2.83{\sim}9.58{\mu}m,\;0.5{\sim}6.73kWh/kg,\;and\;0.51{\sim}3.27m^2/Wh$, respectively. With the wet-type stirred ball mill grinding system used in this study, the grinding energy efficiency decreased with the increase in total grinding time, impeller speed, and mixed ratio. The difference in specific surface area of powder linearly increased with logarithm in total number of impeller revolution and the grinding energy efficiency linearly decreased. Grinding time of 45 min, impeller speed of 500 rpm, and mixed ratio of 6.7 were chosen as the best operating condition. At this condition, mean particle diameter of the fine ash, grinding energy efficiency, grinding throughput, and specific energy input were $2.84{\mu}m,\;2.28m^2/Wh,\;0.17kg/h$, and 2.03kWh/kg, respectively. Wet fine grinding which generates no fly dust causing pollution and makes continuous operation easy, is appeared to be a promising solution to the automatization of rice husk ash grinding process.

Dry Fine Grinding of Rice Husk Ash using a Stirred Ball Mill (교반 볼밀을 이용한 왕겨재의 건식 미세분쇄에 관한 연구)

  • 박승제;최연규;김명호;이종호
    • Journal of Biosystems Engineering
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    • v.25 no.1
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    • pp.39-46
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    • 2000
  • This work was conducted to study the operating characteristics of a grinding system designed to obtain fine rice husk ash powder. To find better utilizing of rice husk, a valuable by-product from rice production, once the rice husk was incinerated and the thermal energy was recovered from the furnace, the ash was fed and pulverized in the grinding system resulting a fine powder to be used as a supplementary adding material to the portland cement manufacturing . The rice husk ash grinding system consisted of a high speed centrifugal fan for the preliminary coarse milling and a dry-type stirred ball mill for the subsequent fine grinding . Total grinding time 9 5, 15, 30, 45 min), impeller speed (250, 500, 750 rpm) , and mixed ratio (4.8, 7.9, 14.9) were three operating factors examined for the performance of a stirred ball mill used for the fine grinding of ash. With the stirred ball mill used in this study, the minimum attianable mean diameter of rice husk ash powder appeared to be 2 ${\mu}{\textrm}{m}$. During the find grinding, the difference in specific surface area of powder showed an increase and the grinding energy efficiency decreased with the increase in total grinding time, impeller speed ,and mixed ratio. For the operating conditions employed , the resulting mean diameter of fine ash powder, specific energy input, and grinding energy efficiency were in the range of 1.79 --16.04${\mu}{\textrm}{m}$, 0.072-5.226kWh/kg, an d1.11-12.15$m^2$/Wh, respectively. Grinding time of 30 min , impeller speed of 750 rpm, and mixed ratio of 4.8 were chosen as the best operating conditions of the stirred ball mill for fine grinding . At these conditions, mean particle diameter of the fine ash, grinding energy efficiency, grinding throughtput, and specific energy input were 2.73${\mu}{\textrm}{m}$, 3.95$m^2$/Wh, 0.25kg/h, and 1.22kWh/kg, respectively.

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A Study on the Internal Grinding of Tungsten Carbide Materials to Improve the Machining Performance (초경합금재의 내면연삭에서 가공능률 향상에 관한 연구)

  • Heo, Seoung Jung
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.6
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    • pp.52-58
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    • 1996
  • This paper described on the effect of residual stocks in internal grinding of tungsten carbide materials in order to improve the grinding efficiency as well as grinding accuracy. Through the fundamental investigation is carried out for tungsten carbide materials using electroplated diamond wheel, the residual stock after grinding process is effective to the grinding efficiency. The obtained results are as follows: (1) Under the depth of cut(t) is constant and decreasing the workpiece velocity(Vw), the residual stock after grinding is increased, but the difference is little less than the difference by table speed. (2) Increasing the wheel velocity, the residual stock after grinding is decreased. Therefore in order to minimize the residual stock, the wheel velocity should be increased as far as possible. (3) The surface roughness and out-of roundness increased with depth of cut and table speed, and decreased with wheel velocity, but it may as well adopt as much as possible under the dimensional tolerance which is required for high efficiency grinding. (4) In order to remove residual stock, the spark-out grinding shoule be done, and it also can be improved about 20~25% throughout spark-out grinding, and the number of optimal spark-out times were within 10 times.

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Evaluation of Pre-estimation Model to the Inprocess Surface Roughness for Grinding Operations

  • Kim, Gun-Hoi
    • International Journal of Precision Engineering and Manufacturing
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    • v.3 no.4
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    • pp.24-30
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    • 2002
  • In grinding operations, one of the most important problems is to increase efficiency of process. In order to achieve this purpose, it is necessary to administer the tool lift of grinding wheel and to optimize grinding conditions. Frequently dressing result in lowering the process efficiency remarkably and makes production cost high. On the other hand, grinding with a worn wheel causes the workpiece surface roughness to increase and often results in the occurrence of such troubles as chatter vibration and homing.

Evaluation of Pre-estimation Model to the Inprocess Surface Roughness for Grinding Operations (연삭가동용 Inprocess 표면조도 예측모델의 평가)

  • 김건희
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1998.03a
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    • pp.11-18
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    • 1998
  • In grinding operations, one of the most important problems is to increase efficiency of process. In order to achive this purpose, it is necessary to administer the tool life of grinding wheel and to optimize grinding conditions. Frequently dressing result in lowering the process efficiency remarkably and makes production cost high. On the other hand, grinding with a worn wheel causes the workpiece surface roughness to increase and often results in the occurrence of such troubles as chatter vibration and burning.

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A study on the internal high-speed grinding (고속 내면 연소에 관한 연구)

  • An, Sang-Ook;Inasaki, Ichiro
    • Journal of the Korean Society for Precision Engineering
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    • v.10 no.2
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    • pp.190-196
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    • 1993
  • Internal high speed grinding under several high grinding wheel speed condition has been performed in this study for the effects have analyzed and compared with the grinding power, grinding tangential force and accuracy of surface with the carbon tool steel(SK3). The following results have been obtained: (1) Under the workpiece speed constant condition, increasing the grinding speed, the tangential force is decreased, and on the contrary, accuracy of surface is improved. (2) Under the speed ratio (V$_{w}$/V$_{s}$) contant condition it is possible to increase the high machining efficiency constraint to tangential grinding force constant.ant.

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A study on machining of high strength ceramics for automobile engine parts (자동차 엔진 부품용 고강도 세라믹스의 기계 가공에 관한 연구)

  • 강재훈
    • Journal of the korean Society of Automotive Engineers
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    • v.12 no.5
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    • pp.60-75
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    • 1990
  • Advanced Ceramics have some excellent prosperities as the material for the mechanical component. It is, however, very difficult to grind ceramics with high efficiency because of their high strength, hardness and brittleness. In this study, various machining experiments are carried out to obtain the basic knowledge of grinding High Strength Ceramics with high efficiency and precision for the purpose of application to Automobile parts. Advanced Engineering Ceramics such as Si$_{3}$N$_{4}$, SiC, ZrO$_{2}$, $Al_{2}$O$_{3}$ are ground with diamond wheels using conventional grinding machine. Results obtained in this study provide some useful informations to attain the high efficiency grinding of Advanced Ceramics.

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Grinding Characteristic of Advanced Ceramics (파인세라믹의 연삭가공특성)

  • Jung, Yoon-Gyo;Kang, Jae-Hoon
    • Journal of the Korean Society for Precision Engineering
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    • v.7 no.2
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    • pp.105-112
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    • 1990
  • Advanced ceramics have some excellent properities as the material for the mechanical component. It is, however, very difficult to grind ceramics with high efficiency because of their high strength, hardness and brittleness. In this paper, some experiments are carried out to find the basic grinding characteristic of advanced ceramics. Representative advanced ceramics, such as AL/sub 2/ O/sub 3/, ZrO/sub 2/, SiC and Si/sub 3/N/sub 4/and ground with diamond wheels. Special attention is paid to comparison between the conventional and creep feed grinding. Results obtained in this study provide some useful informations to attain the high efficiency grinding of advanced ceramics.

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