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.
Polycrystalline Diamond (PCD) radial bearings are comprised of a series of PCD inserts assembled (usually by brazing) in carrier rings. A typical PCD radial bearing set includes a rotating and stationary bearing ring. These two rings oppose each other with the PCD surface on the inside diameter of one ring in direct contact with the PCD surface on the outside diameter of the mating ring.
US Synthetic Bearings prides itself in its ability to precisely shape polycrystalline diamond. This has allowed Bearings to provide PCD radial bearings that have accurate diameters, tight clearance tolerances, and ultra-fine surface finishes.
During operation, the PCD surfaces of the rotating and stationary rings rub against each other. This rubbing contact exhibits very low friction (typically between 0.01 and 0.05).
The ultra-high hardness and strength of PCD allows USS Bearings’ radial bearings to sustain very high loads during operation. In addition, they wear at a very low rate, resulting in the PCD bearings lasting from 1000 hours to many years, depending on the application. These PCD inserts also utilize the highest quality steel grade available.
PCD radial bearings are ideally suited for process-fluid-lubricated applications, particularly those where abrasive particles are present in the fluid. The PCD surfaces maintain their geometry and exhibit minimal wear in the presence of these abrasive-laden fluids.
US Synthetic Bearings’ radial bearings are custom designed for each application. The Bearings’ engineering team can create a specific design for your application and provide performance estimates for its bearings in that application. Contact us for more information.
Polycrystalline diamond is an extremely wear resistant material that can be used to protect drilling tool components from abrasive wear caused by contact between the exterior of the tool and the bore-hole wall.
US Synthetic wear parts made of PCD can be used on internal drilling tool components to protect critical surfaces from erosion caused by high-velocity abrasive fluids. In one case, PCD has been used as a replacement for tungsten carbide components that were subjected to accelerated erosion.
Tilting Pad Bearing
All US Synthetic PCD bearings and wear parts are custom designed for each application. We work closely with our customers to develop bearings that can be easily integrated into existing or new tools. The US Synthetic Bearings engineering teams provide design support, prototype manufacturing, and in-house laboratory testing to help our customers meet the needs of their specific applications.
Diamond Tilting pad Datasheet (PDF download)
Why Diamond Bearings Underwater?
PCD bearings are ideally suited for operation in process fluids where abrasive particles can cause accelerated wear. Pumping abrasive-laden liquids or mixed phase fluids is a tough job. That’s why, US Synthetic offers the most durable, longest-lasting bearings specifically designed for transfer pumps, Electric Submersible pumps (ESP), stationary pumps, and injection pumps.
Oil and Gas Drilling
When there’s simply no room for error or failure, US Synthetic prides itself on offering the longest-lasting diamond bearings and components on the market for down hole drilling tools.
Oil and Gas Drilling Datasheet (PDF download)
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