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Toolholders accept 400 bar; supply 360 bar coolant pressure
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June 2007
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Iscar has tailored toolholders for very high pressure coolant applications of up to 400 bar presure supply, delivering 360 bar at the toolholder.
Since 2000 Iscar has worked with Snecma on the development of a cutting tool coolant system that will provide the aerospace industry with an effective coolant supply in extreme machining conditions. The objective has been to overcome the problems of extreme heat generation and swarf removal associated with both internal and external deep grooving and profiling operations. These problems are inherent when working on aerospace components that include titanium casings, low pressure disks and drums for jet engines.
Technical solutions for grooving were initially developed in 2000 with further innovations allowing Iscar to develop a solution for ISO inserts capable of using very high coolant pressure (up to 400 bar) in 2002. The use of such high pressure puts severe demands on the machine tool as conventional turret and spindle seals cannot withstand the pressure. To use the technology successfully, a high pressure pump has to be retrofitted to the machine. The coolant also has to be altered to a concentration level of 10 to 12 per cent to keep misting at a minimum.
The new Iscar tool holders have been specially tailored, so the adapters for left or right cutting can be mounted on one base module. The module consists of four coolant holes; two have high pressure (one left and one right) and two emergency supply holes, should the high pressure supply fail.
In addition, the system employs technology that resolves the issue of potential damage to the machine seals should a blockage occur on the outlet of the system. This new innovation ensures the machine seals avoid damage that can be extremely expensive to correct. The base guarantees maximum rigidity by providing support elements close to the working area. The flexibility of the Iscar system allows numerous tool profile variations to be applied, making it possible to conduct very complex operations.
For Iscar, having 400 bar of pressure at the rear of the tool was an impressive achievement, however the cutting tool innovator beleived it was not enough. Iscar set itself a new goal, to provide a pressure close to the machine supply pressure. To achieve this, Iscar has now developed tools that release 360 bar of pressure. The new system has been adapted to high pressure machining and it guarantees the cutting fluid arrives in a liquid state and not as a form of fog.
The development of these tools has been carried out by Iscar engineers in France with tool production taking place at Iscar Métaldur in Switzerland. For small radii machining below 3 mm, Iscar replaces circular ‘button’ inserts with special forms to suit the grooves to be machined.
High pressure lubrication enables the cutting speed in TA6V titanium discs to be tripled, achieving 140 m/min with a feed rate range from 0.1 to 0.2 mm/rev. The new Iscar machining process is more reliable with less tool breakages, improved tool life and productivity with manufacturing costs significantly reduced.
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Author
Andrew Allcock
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