Laboratory Comparison of SMART*CUT Picks With WC Picks

Application of polycrystalline diamond compact (PDC) based cutting tools for hard rock excavation in mining and construction industries has increased significantly in recent years due to their super hardness, superb thermal conductivity and long life durability. Super Material Abrasive Resistant Tool (SMART*CUT) technology has been developed by CSIRO (Commonwealth Scientific and Industrial Research Organisation) in the last 15 years, which includes the replacement of tungsten carbide (WC) tips of the conventional picks with thermally stable diamond composite (TSDC) tips, attachment of the TSDC tips to steel tool bodies with CSIRO’s worldwide patented bonding technology. The wear characteristics of TSDC cutting elements have been investigated previously. In this paper, the preliminary results of cutter forces and resultant angle of SMART*CUT picks were compared with that of traditional WC picks. A tri-axial force dynamometer and a data acquisition system were used to measure the cutter forces. Besides, the cutting area temperature during cutting process was continuously measured by a FLIR SC7600M thermal infrared camera and the recorded data were processed by Altair Software.

Linear Rock Cutting with SMART*CUT Picks

The short life due to heavy wear is a bottleneck that limits the usage of mechanical excavators for hard rock cutting. Thermally stable diamond composite (TSDC) tipped cutting tools have the main advantages of good thermal stability, high wear resistance and ability to mine harder deposit compared to the conventional tungsten carbide (WC) tipped cutting tools. Super Material Abrasive Resistant Tool (SMART*CUT) based on TSDC tip has been developed by CSIRO to improve the effectiveness of cutting tools when dealing with hard deposit in mining and civil industries. In this study, the effects of attack angle and depth of cut on the cutting performance of SMART*CUT picks in different cutting orientations were investigated. A tri-axial dynamometer and a data acquisition system were used to measure the cutter forces. Normal force, cutting force and resultant angle were correlated with depth of cut and attack angle. Cutting performances were compared in different cutting orientations. The results would be beneficial to the selection of mechanical excavator motor and the optimization of cutting drum design to some extent.

Simulation of Disc Cutter Loads Based on ANSYS/LS-DYNA

In order to solve serious damage of pick on part-face tunnel machine during hard rock cutting, explore the applicability of disc cutter on the machine, the structure of disc cutter was designed, a model of dist cutter was built with Pro/E software, finite element model was established in ANSYS/LS-DYNA, the vertical force and rolling force of a disc cutter were obtained by simulation of cutter cutting. Analysis shows that the disc cutter can cut granite whose hardness is 106.2MPa, so the disc cutter can cut hard rock. The vertical force and rolling force agreed with common prediction formula of disc cutter forces which showed that modeling method is correct and feasible, this paper lays the foundation for the design and development of a cutting head of hard rock roadheader.

Laboratory Comparison of Mini-Discs with Point-Attack Picks

The selection of the cutter type is of crucial importance to maximise the advantages of mechanical rock excavation systems. Specific energy (SE), cutter forces, and rock properties are used to decide what type of cutter is most suitable for economical excavation of the rock based on laboratory rock cutting tests. This study is concerned with the preliminary results of an ongoing rock cutting program in which a mini-disc has been compared with a point-attack pick in laboratory linear cutting tests simulating a cutterhead on a Helidon sandstone block. Analysis of the preliminary results has shown that the mini-disc experienced lower mean cutting forces and was seven times more efficient than the pick in first layer cuts. However, the mini-disc had mean normal forces 1.5 times higher than the pick. Additionally, first layer cuts taken on the trimmed surfaces required more forces and SE than completely relieved cuts in pick cutting.

Energy balance of a drill-bit seismic source, part 2: Drill-bit versus conventional seismic sources

The radiation properties of a downhole drill-bit seismic source are related to the amplitude and frequency of the forces exerted by the working bit. The main vibration modes of roller-cone and polycrystalline diamond compact (PDC) bits are investigated under different drilling conditions. The analysis includes vibrations produced by teeth indention, multilobed patterns, bouncing with periodic and random effects, single-cutter forces, stick-slip and whirling effects, mud-pressure modulation forces, and bit wear. Drill-bit radiation properties are calculated using the results obtained in part 1 of this paper and are numerically compared to the radiation of conventional vertical seismic profiling (VSP) sources.