KAT DRILLING
Engineering Architecture of High-Performance Core Drill Bits
In modern mineral exploration, geotechnical site investigation, and deep geological coring, selecting the optimal core drill bit is the single most critical factor influencing total cost per meter (CPM) and core recovery ratio. As a premier China CoreDrillBit Manufacturer & Factory, Shandong KAT Drilling Tools integrates metallurgical metallurgy, precision diamond sintering, and computational fluid dynamics (CFD) to engineer core bits capable of penetrating abrasive crystalline rock formations.
1. Impregnated Diamond Core Bits: Matrix Hardness Selection Guide
Impregnated diamond core bits utilize a sintered matrix consisting of synthetic micro-diamonds uniformly distributed within a specialized metallic alloy matrix. As the bit rotates against abrasive formations, the metallic matrix wears away at a controlled rate, continually exposing fresh, sharp diamond cutting edges. Matrix selection depends on the ground hardness and abrasiveness rated on the Mohs scale:
| Matrix Series | Rock Formation Hardness | Mohs Hardness Range | Compressive Strength (MPa) | Recommended Bit Profile |
|---|---|---|---|---|
| Soft/Medium (K-Series 1-4) | Shale, Sandstone, Soft Limestone | Mohs 2.0 - 4.5 | < 80 MPa | Flat, Multi-Waterway Discharge |
| Hard/Abrasive (K-Series 5-8) | Granite, Dolomite, Medium Quartzite | Mohs 5.0 - 7.0 | 80 - 180 MPa | Semi-Round / V-Crown Matrix |
| Ultra-Hard/Broken (K-Series 9-12) | Basalt, Taconite, Chert, Quartz | Mohs 7.5 - 9.0+ | > 200 MPa | Deep-Discharge Pie-Shaped / Turbo |
2. Polycrystalline Diamond Compact (PDC) Cutting Thermodynamics
Unlike impregnated diamond bits that grind rock via micro-chipping, PDC core bits operate through a continuous shearing mechanism. Modern PDC cutters consist of a polycrystalline diamond layer integrally cobalt-bonded to a tungsten carbide substrate under ultra-high pressure and temperature (HPHT). This delivers extraordinary impact toughness alongside extreme abrasion resistance.
In soft to medium-hard non-abrasive strata (e.g., mudstone, salt, marl, and soft shale), PDC core bits yield penetration rates up to 3 to 5 times faster than traditional surface-set diamond bits. The cutter geometry, back-rake angle (typically 15° to 20°), and side-rake angle are precisely tuned to facilitate rapid chip evacuation and minimize thermal degradation of the PDC table.
3. Hydraulic Flushing Channel Design & Core Preservation
Flushing mechanics are paramount in core drilling to prevent bit burn, bit balling, and core erosion. Shandong KAT incorporates computer-modeled fluid channels into every drill bit configuration:
- Standard Waterways: Optimized for competent rock cores where fluid flows over the matrix face directly.
- Face-Discharge Channels: Crucial for friable, highly fractured, or soft formations. Flushing fluid is directed straight to the matrix cutting face without spraying onto the internal core, preventing fragile core washing and maximizing core recovery ratios.
- Turbo / Radial Channels: Designed for high-speed wireline drilling systems, increasing fluid velocity to flush heavy slurry away from the cutting zone instantly.
