Cold Root Rolling on a FAT HACO lathe
In industrial production, we distinguish various types of machining of raw materials from which appropriate tools and components are produced. This is also the case with the production of downhole drill tools, which is a key process for the oil & gas industry. Drill tools are used to drill holes in the ground or rocks, which can be used in the search for natural resources, oil drilling, geotechnics, construction or drilling deep wells.
The downhole drill tool production process may include machining, turning and thread forming. Shafts and pipes, including drill tools, are common components used to transmit power and transport fluids. Thread forming is used to process the ends of shafts connecting rods and to ensure adequate durability of the threads.
Burnishing the thread profile (Cold Root Rolling) - A hardened roll, similar in profile to the thread being manufactured, is placed in contact with the root radius of the tapered thread, and pressure is applied to force the roller to penetrate into the cut surface of the root radius, displacing and cold-forming the thread material. Cold Root Rolling displaces the material, compacting the previously cut and displaced grains, resulting in a harder, compact surface. This is plastic processing that kneads material that has previously been machined.
This process is common practice in thread finishing and is popular throughout the drilling industry due to its numerous benefits: including increased fatigue resistance, increased torque capacity, improved performance, minimized cracking and longer thread life.
This process requires high feed force. TUR MN series lathes with a spindle bore up to 450 mm have a sufficiently high feed force in the X axis (25 kN) to properly perform thread forming. For example the TUR SMN 800 with a 220 mm spindle bore has also good feed force (20 kN) of X axis. Another advantage of FAT HACO machines is the monolithic bed. The one-piece construction ensures excellent structural integrity, resulting in better material-forming properties.
We use CJ Winter tools on FAT HACO lathes. It is an error-resistant, stand-alone tool system equipped with a hardened wheel and a clear pressure gauge display that does not require external power supply. The tooling is mounted on the tool head and can be used with a boring bar for internal burnishing or with a square shank for external burnishing . The instrumentation can be easily adapted to Siemens numerical control cycles, and in combination with a CNC lathe from FAT HACO, it becomes an excellent solution for production processes in the oil & gas industry.
CJ WINTER tools for Cold Root Rolling