ISCAR Whisper – A Quiet Revolution in Anti-Vibration Tools
Vibration is a problem machinists deal with on a daily basis.
To solve this problem, ISCAR’s R&D department has developed a wide range of anti-vibration tools that are able to reduce or even eliminate vibration across a wide range of machining disciplines. Today, ISCAR’s acknowledged expertise in the design and development of anti-vibration tools has been applied to the Boring Bar.
The boring of components is one of the most common turning applications. This is a function also known as internal turning. The most widespread tools used for this type of machining operation are boring bars. Boring bars’ shapes enable them to operate through previously drilled holes. This allows them to efficiently enlarge and accurately profile holes according to their specific requirements.
The correct application of a boring bar enables a bore’s internal profile to be machined according to specification, an accurate hole diameter to be achieved, and the required surface finish quality to be realised.
In order to cover the complete range of applications for internal turning, ISCAR has developed a comprehensive series of high-quality internal boring bars for different insert geometries, covering all machining applications from 4 x BD to 10 x BD.
ISCAR offers three types of boring bars: Solid Steel, Solid Carbide, and Anti-Vibration.
The maximum overhang for solid steel boring bars is up to 4 x BD. This limitation is due to the fact that machining with a longer length of steel shank (more than 4 x BD) can induce unwelcome vibrations due to the elasticity and characteristics of steel.
In order to limit the vibration on a higher overhang of more than 4 x BD and up to 6 x BD, the use of solid carbide boring bars is recommended. Solid carbide boring bars represent an excellent, highly-efficient option for boring applications of up to six times the tool’s machining depth. This capability is attributable to solid carbide possessing a co-efficient of elasticity that is three times higher than that of steel.
However, when the machining of high overhangs of more than 6 x BD is required, even the use of a solid carbide shank can cause vibrations. Therefore, in these cases the use of solid carbide can be somewhat limited.
Deep turning solutions for machining high depth to diameter internal applications include special anti-vibration boring bar systems with a ‘live’ vibration dampening system located inside the tool body.
A product of ISCAR’s prolific R&D department, innovative WHISPER LINE anti-vibration boring bars have been designed to significantly reduce and even totally eliminate vibrations when working with a high overhang from 7 x BD to 10 x BD.
Inside these tools is a unique damping mechanism. It consists of a heavy mass that is supported by a rubber spring element containing oil to increase the required dampening effect.
In addition, the system contains other elements which help to further reduce vibrations. The reactive damping mechanism comes into action during machining with high overhang work depths, and acts as an effective counter to vibrations.
The highly-effective, anti-vibration damper effect is applicable for large DOC and high feed rates. It ensures continuous, efficient machining. ISCAR’s WHISPERLINE anti-vibration tools considerably improve machining stability and enhance insert life. These factors enable increases in productivity to be achieved, improvements in surface quality on high overhangs to be attained, scrap levels to be reduced, and users’ profitability to be enhanced.
WHISPERLINE anti-vibration tools enable the delivery of internal coolant to be supplied directly to where it is required – the insert’s cutting edge. The efficient distribution of coolant increases the insert’s tool life by reducing temperature, and also improved chip control and chip evacuation.
The WHISPERLINE anti-vibrations turning tool line enables the fitting of a wide range of cutting heads with a range of different insert geometries. This includes all ISCAR-standard ISO turning inserts for different applications for greater flexibility.
For machinists looking for a cost-effective, modular system, WHISPERLINE promises strong results. It boasts a wide range of standard shanks with diameters of 16, 20, 25, 32, 40, 50, and 60mm. The flexible boring bars are able to carry eight different interchangeable boring heads. These include: CCMT, VCMT, TCMT, DCMT, TNMG, DNMG, SNMG, and VNMG.
Correct insert geometry is an important factor when using anti-vibration boring bars.
The most recommended insert geometry for successful anti-vibration use is a positive geometry insert with a positive rake angle. This is because this shape exerts a lower tangential cutting force when machining.
Choosing the appropriate nose radius of the insert is also a vitally important consideration. A lower nose radius is recommended as this configuration significantly reduces the cutting forces, due to the lower contact between the insert and workpiece, which helps to limit and reduce vibration. A greater nose radius creates much larger radial and tangential cutting forces that can produce unwelcome vibrations.
Inserts with the benefit of appropriate chip breakers are recommended for improved chip evacuation, as the production of long and curled chips can cause a range of problems when working with long overhang tools. In addition to increasing vibration during machining, long and curled chips are liable to spoil or damage the surface quality of the workpiece.
Highly recommended ISCAR chip breakers for anti-vibration tools are the F3P/F3M for finish machining applications using a small DOC; and the M3/M3M for medium applications. These highly-efficient chip breakers ensure excellent chip control and the creation of small chips, which can be evacuated more easily with the help of the coolant supply.
An additional, very important factor in reducing vibrations is ensuring the clamping stability of the anti-vibration boring bar. Secure clamping helps users to achieve the correct workpiece dimension, which results in excellent workpiece surface quantity and assists in avoiding vibrations. Clamping length should be 4 x BD.
ISCAR’s new, anti-vibration boring bars join the ever-growing ISCAR WHISPERLINE family of tools that are designed for anti-vibration turning and grooving applications. The all-embracing anti-vibration turning tools can be referred to as tuned or dampened tools, which provide effective solutions for the reduction and elimination of vibrations.