In quarrying operations, Down-The-Hole (DTH) hammer drilling is a fundamental process for blast hole drilling, enabling efficient rock fragmentation. While traditional DTH bits typically utilize tungsten carbide buttons, the integration of Polycrystalline Diamond Compact (PDC) dome buttons represents a cutting-edge advancement, offering unique solutions for specific and challenging quarry conditions.
The primary function of a DTH drill bit is to withstand immense impact energy from the hammer while effectively crushing and shearing rock at the bottom of the hole. Conventional carbide buttons excel in fracturing a wide range of rock types through percussive force. However, in extremely hard, abrasive, and non-fracturable formations like hard quartzitic sandstone or granite, carbide wear can be rapid, leading to decreased penetration rates, frequent bit changes, and higher costs.
This is where PDC dome buttons find their strategic niche on DTH bits. By strategically placing them in critical wear zones—particularly on the bit's gage (outer diameter) and possibly on the center—drill bit manufacturers aim to combat severe abrasion. The extreme hardness and wear resistance of the PDC layer can significantly extend the operational life of the bit in these harsh environments. While the central rows of buttons still rely on robust carbide for impact-driven rock crushing, the PDC-enhanced gage maintains hole diameter and stabilizes the bit for longer periods.
The PDC button for making DTH drill bit
The PDC (Polycrystalline Diamond Compact) Spherical Button is a premium cutting teeth designed for these demanding applications. Its name derives from its specific geometry and size. This button is composed of a layer of synthetic polycrystalline diamond, the hardest known material, fused under high pressure and temperature to a tungsten carbide substrate. This combination creates a cutting element that is both incredibly hard on the surface (for abrasion resistance) and exceptionally tough in its core (to withstand heavy impact loads).
Case:
The DTH drill bit installed with PDC button, has been applied to a quarry abroad, drilling into granite formations for making blasting holes.
The DTH drill bits have a feed rate 30-40% faster than carbide drill bits, consume 20-25% less oil, and extend the lifespan of impactors by 20%. Diamond drill bits have a lifespan 3-3.5 times that of alloy drill bits. In field tests, alloy drill bits wore out too quickly, frequently causing jamming during later drilling operations, while diamond drill bits never experienced jamming.
