• Title/Summary/Keyword: 코니컬커터

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Performance estimation depending on the insert size of conical picks by linear cutting test (선형절삭시험에 의한 코니컬커터의 삽입재 크기에 따른 절삭성능 평가)

  • Choi, Soon-Wook;Kang, Tae-Ho;Chang, Soo-Ho;Lee, Cheol-Ho;Lee, Gyu-Phil;Kim, Chang-Yong
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.18 no.2
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    • pp.221-233
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    • 2016
  • In order to estimate the performance of a conical cutter depending on the insert size, this study measured forces acting on conical cutters with different cutter spacings, penetration depths and skew angles using slim and heavy conical cutters. When cutter spacings ranged from 12 to 27 mm, the deviations of mean cutter forces with cutter depths appeared smaller compared to other cutter spacings. When skew angle is $0^{\circ}$, the optimal S/d ratio was obtained in the range of 4 to 4.5 for which specific energy of cutting was minimized. It were usually found in the range of 1 to 5. However, when skew angle is $6^{\circ}$, the optimal S/d ratio was obtained in the range of 1 to 3. The simple comparison results shows that the performance of slim cutter was superior to that of heavy cutter, but the use of heavy cutter can be effective, considering the cutter consumption and cutter damage when the strength of the ground is high enough.

Performance estimation of conical picks with slim design by the linear cutting test (I): depending on attack angle variation (선형절삭시험에 의한 슬림 코니컬커터의 절삭성능 평가(I): Attack Angle 변화에 의한 결과)

  • Choi, Soon-Wook;Chang, Soo-Ho;Park, Young-Taek;Lee, Gyu-Phil
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.16 no.6
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    • pp.573-584
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    • 2014
  • In this study, the variations of cutter acting forces depending on cutting conditions were examined to obtain basic data for roadheader cutting head design. The linear cutting tests were performed in the condition of different attack angles, penetration depths, cutter spacings by using a slim conical pick for the light cutting condition. Cutter acting forces were measured by 3-directional load cell under different test conditions, and the analysis for cutting performance were carried out after calculating average values of the measured results. It is confirmed that the optimal cutting condition for the mortar specimen is the 50 degree attack angle, the cutter spacing of 12 mm, the cutting depth of 9 mm which are obtained from the analysis results. In addition, 50 degree attack angle is more effective than 45 degree attack angle to design optimal specifications of cutting head.

Durability evaluation depending on the insert size of conical Picks by the field test (삽입재 크기에 따른 코니컬 커터의 현장 내구성 평가 연구)

  • Choi, Soon-Wook
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.21 no.1
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    • pp.49-59
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    • 2019
  • In this study, the durability of conical pick cutter was compared and analyzed by pre- and post-test visual inspection, measurement of weight loss and wear volume through field test on two types of conical pick cutters applied to rotary drum cutter. In the visual inspection, it was found that only 9 inserts were lost in the slim type conical pick cutter. This result show that the thickness of the head cover surrounding a insert was important to maintain the insert during excavation. The weight loss and wear volume of the heavy type conical pick cutter were less than half that of the slim type. From these results, it can be confirmed that heavy type is more useful than slim type in hard rock. It should be noted that, when determining the wear loss of the conical pick cutter, the mutual comparison of the weight measurement and the wear volume measurement results may be different due to the unit weight of the material and the spalling caused by excavation.

Performance estimation of conical picks with slim design by the linear cutting test (II): depending on skew angle variation (선형절삭시험에 의한 슬림 코니컬커터의 절삭성능 평가(II): Skew Angle 변화에 의한 결과)

  • Choi, Soon-Wook;Chang, Soo-Ho;Lee, Gyu-Phil;Park, Young-Taek
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.16 no.6
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    • pp.585-597
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    • 2014
  • In this study, the cutter acting forces were measured by 3-directional load cell at two different skew angles and various S/d ratios during a series of linear cutting tests using a slim conical pick. The analysis for cutting performance were carried out after calculating average values of the measured results. The increase of penetration depth results in the decrease of specific energy. And the variations of the cutter acting forces depending on penetration depth in the case of 6 degree skew angle were smaller than in the case of 0 degree skew angle. From this results, 6 degree skew angle is more effective than 0 degree skew angle in designing optimal specifications of cutting head. In addition, $F_c/F_n$ under the setting of 6 degree skew angle was smaller than under the setting of 0 degree skew angle. However, it should be considered that the increase of cutter acting force in the cutting direction accompanied the increase of driving force in the case of the setting for 6 degree skew angle.