Special "Ventus" machine plays integral role in production of diamond drill bits for offshore use
Special "Ventus" machine plays integral role in production of diamond drill bits for offshore use
Keywords: Cutting, Drilling
A specially adapted, semi-automatic "Ventus 125P" abrasive blasting machine designed and manufactured by USF Vacu-Blast International, forms an integral part of a high-tech production line for diamond drill bits at Reed-Hycalog, Stonehouse, near Gloucester.
Part of the global Schiumberger group, a world leader in oil and gas exploration and associated equipment, Reed-Hycalog is an established specialist in the technology and production of diamond drilling bits. The company has developed special "mixes" of industrial diamonds in a matrix of tungsten, which have been designed to increase rates of penetration of drill bits and, at the same time, ensure a long operating life. The mixes take the form of 19mm or 13mm diameter circular cutting tools which are used as inserts in various multiples and patterns – depending on the particular application– to make up the actual full sized drill bit (see Plate 3).
These circular cutters are manufactured by a highly sophisticated, patented,computer-controlled process involving the "bonding" of the diamond powder under immense pressure (around one million pounds per square inch) and at very high temperature – simulating the way diamonds are produced naturally. During this process, the mix is retained in a soft refractory metal "can",which is subsequently machined off.
Plate 3 The mixes take the form of 19mm or 13mm diameter circular cutting tools
Following this process, it is necessary to condition the polycrystalline diamond surface to achieve the surface profile necessary for efficient cutting. The first stage of this crucial operation is carried out in the Ventus abrasive blasting machine, which uniformly etches the surface in line with specified parameters. The cutters are processed two at time in the machine, retained in purpose-designed rotating jigs, and each is blasted individually with black silicon carbide media by a twin pressure-fed blast nozzle array. The process is automatic, apart from loading and unloading the machine, and the cycle time is 3.5 minutes. Both component rotation speed and cycle time can be varied to suit the diameter of the cutter (13mm or 19mm). A further control measure is a special media valve that starts and stops the blasting action instantly so that under- or over-blasting cannot occur.
Although the machine has built-in COSHH-compliant dust filtration, it is housed in a special enclosure which incorporates additional HEPA filtration to totally eliminate the risk of dust emission.
After blasting, the cutters undergo final lapping and machining operations before being assembled onto the drill bits.
Reed-Hycalog produces some tens of thousands of these circular cutters a year which are well proven in offshore drilling operations throughout the world.
The USF Vacu-Blast "Ventus 125P" machine has a 1,250mm x 1,000mm x 950mm high processing enclosure, and is one of a range of "Ventus"cabinet blasting machines covering enclosure sizes up to 2,000mm x 2,000mm x 2,000mm. Each features an integral blast media recovery system which automatically recycles reusable media back to the blast nozzle, and includes a COSHH-compliant reverse-jet dust collector with a quick-release filter cartridge.
For more information contact: USF Vacu-Blast International, Woodson House,Ajax Avenue, Slough, Berkshire SL1 4DJ, UK. Tel: +44 (0) 1753 526511; Fax: +44(0) 1753 538093; E-mail: MAILTO:info@vacu-blast.co.uk
