• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.7
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• pp.685-692
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• 2016

A cutting head is an attachment on the front of an excavator that cuts or grinds rocks. Cutting tools, called pick cutters, are arranged on the surface of the cutting head. The exact arrangement and configuration of pick cutters is one of the most important factors in determining grinding efficiency. This study focuses on the problem of automation for pick arrangement design, in order to make the design process more efficient and convenient. Design automation was carried out using RecurDyn/ProcessNet, and it was composed of three parts: 'Drum set', 'Pick load', and 'Pick arrangement' sections. The presented method helps to decrease costs attributed to designing cutting heads and can be used to generate a wide range of attachment mechanisms.

• Magazine of korean Tunnelling and Underground Space Association
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• v.17 no.1
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• pp.44-51
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• 2015

• Tunnel and Underground Space
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• v.25 no.6
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• pp.496-504
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• 2015

Roadheader that excavates ground using pick cutters installed on the cutting head is one of the partial-face machines. A conical cutter among pick cutters is excavation tool decreasing the loss of cutter using tungsten carbide insert at the tip of the cutter and it has been widely used in the roadheaders. In this study, durability performance for three kinds of conical cutters was evaluated in copper mines composed of Manto and conglomerate. After field test, the visual inspection as well as the weight loss measurement of pick cutters was carried out to investigate the damage of pick cutters. In addition, CT scan and SEM were performed to check whether or not crack and apertures in pick cutters. As results, the conical cutter with hardfacing was evaluated as having the best durability performance and it was unable to find cracks in all cutters investigated.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.5
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• pp.535-540
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• 2011

It is well known that abrasive waterjet (AWJ) was developed as a kind of high-density energy processing technologies. AWJ is used to obtain cutting quality of various materials such as metal, ceramics, glass and composite materials within a short manufacturing time because of the characteristics of heatless and noncontact processing. However, surface roughness and dimension error like round, burr, taper vary severely according to the processing conditions such as pressure, cutting speed, orifice diameter, stand off distance and abrasive flow rate. In this paper, the effect of the shape of mixing chamber on surface quality is studied. Three types of mixing chamber - round, parabolic, elliptical - are suggested and each performance is compared to that of cylindrical mixing chamber experimentally. From the result, is proved to be the optimal mixing chamber in the aspect of surface quality the parabolic one.

• 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.

• Tunnel and Underground Space
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• v.23 no.5
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• pp.428-441
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• 2013

Nowadays, a roadheader as a mechanical excavator is in high demand, especially for mines under various conditions and tunnels where TBMs are inapplicable. However, the records of roadheaders in Korea are seldom reported. Moreover, the number of countries with their intrinsic design and manufacturing technologies of roadheaders is very limited. Therefore, this study aimed to analyse the excavation principles of roadheader as well as its key design parameters for its optimized selection and design. In addition, the database with 143 world-widely collected roadheader design data was built, and a few statistical correlations were derived from it. A schematic procedure for roadheader design based on the database was also proposed.

• 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.