The extreme hardness, wear resistance, and thermal conductivity of diamond make it an ideal cutting tool material. However, individual diamond crystals cleave quite easily when struck parallel to certain planes (the process used to facet diamond gemstones takes advantage of these relatively weak planes). As a result, individual diamond crystals do not make good cutting tools—unless they are meticulously oriented.
Diamond sintering overcomes the problem of weak planes in diamond gemstones by bonding a mass of small diamond particles onto a larger, coherent structure. Sintered diamond provides greater toughness and durability than single crystals because the individual crystals in a sintered body are randomly oriented. This prevents cracks from propagating along the weak planes where traditional diamond crystals cleave most easily. Sintered diamonds also provide more uniform wear than a single crystal, while maintaining similar thermal conductivity and hardness properties. All of these factors combine to make sintered diamond the preferred material for cutting rock.
At US Synthetic, the sintering process begins with premium saw-grade diamond crystals. These crystals are sintered together at temperatures of approximately 1400°C and pressures of around 60 kbar in the presence of a liquid metal catalyst. Typically, the diamond is bonded to a tungsten carbide substrate during the same high-temperature, high-pressure process. This sintered diamond and tungsten carbide composite is known in the industry as a polycrystalline diamond cutter (PDC).
The extreme hardness of diamonds presents obvious machining and finishing challenges. In typical machining situations, the finishing tool is harder than the work piece. With diamond inserts, this isn’t possible, since diamond is the hardest known substance. This makes machining diamond analogous to cutting through a wooden beam with a wooden saw. As a result, US Synthetic uses millions of carats of industrial diamond each year to machine and finish PDCs to their final dimensions. Over the years, we have developed specialized techniques and machines for lapping, grinding, polishing, brazing, and cutting PDC inserts. These techniques make it possible for us to finish PDCs to exacting specifications, despite the inherent challenges of machining sintered diamond.
Using diamond inserts in traditional rock bits can boost performance, increase durability, and dramatically improve drilling economics. Diamond-enhanced rock bits also make it possible to drill formations that are too difficult for traditional tungsten carbide inserts.
Since 1994, US Synthetic has been designing and manufacturing some of the most technically advanced and innovative diamond rock bit products in the industry. This includes using diamond inserts in many different strategic bit locations, from inner row use to gauge protection on the cones or bit body.
US Synthetic is able to design and manufacture bit inserts that meet virtually any size or shape requirement, including ovoids, conicals, and chisels, and is constantly searching for new shapes that make more effective use of diamond. The rock bit inserts range in size from 5mm to 25 mm in diameter and 3mm to 35mm in length.
Continuing in its missions of innovation and servicing customers with customized engineering, US Synthetic is always ready to design and manufacture rock bit inserts to match the customers’ unique specifications, including customized diameters, lengths, shapes, and chamfers.
US Synthetic uses diamond to solve important problems today, but we also realize that we’ve only begun to explore the possibilities. Because synthetic diamond has many unique properties, that makes it ideal for a wide range of uses both inside and outside the oil and gas exploration industry, and new possibilities and opportunities are continually be explored.
For new ideas or suggestions for using diamond, please contact US Synthetic business development. US Synthetic welcomes the opportunity to put synthetic diamond to work for your business.
The Unique Properties of Diamonds
- Hardest known material
- Highest thermal conductivity
- Highest wear resistance
- Excellent electrical insulator
- Extremely low thermal expansion
- Low coefficient of friction
- High sonic velocity
- Optically transparent
- Wide band-gap semiconductor
- Chemically inert
- Biologically compatible