CBN-tipped cutting inserts unveiled

The 315 system from Horn for internal and external grooving has gained a new range of single-edged, CBN-tipped inserts suitable for hard machining applications. Inserts are available for producing grooves from 1 to 3 mm wide and up to 5 mm deep.

A large contact area on the insert seats directs the cutting pressure efficiently into the holder, while the central clamping screw enables maximum tightening of the insert for vibration-free, accurate machining. These properties make the system suitable for counteracting the high forces generated during hard turning. The holder range is available in monoblock design and as a cartridge system for HSK-T and PSC connections.
In other product news from Horn Cutting Tools, the company says that Boehlerit’s new turning tool holders with connections for internal coolant supply are now available in the UK. The holders are available from stock with toggle clamp (ISO-P) and screw clamp (ISO-S) systems, allowing manufacturers to benefit from the productivity advantages of cooling directly at the cutting edge.
The P variety is suitable for all ISO indexable inserts. There are no loose components and only a few spares are required, making them easy to handle. According to Horn, inserts can be clamped quickly and securely, and released easily, while chip flow is smooth as there are no obstructions.
S-type tool holders also enable the insert to be secured simply and safely, in this case using a cone-shaped positioning screw. Here too, chip flow is not compromised and a maximum of three spare parts is needed.
For both types of holder, the coolant is supplied at the back of the shank end as standard, or from below the head as an option.
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High-productivity hard turning

A new solution for higher productivity hard turning at higher speed and feed rates is based on more economic use of a specific design of octagon insert incorporating special wiper geometry that enhances surface finish.

The Sumitomo Electric Hardmetal High Feed Turning (HFT) system leverages the company’s experience in CBN insert technology.
HFT hard-turning trials have resulted in 12 to 16 times faster processing times over existing methods, while enabling existing component surface finish and tolerances to be maintained. However, adding to the success of the trials, insert life was doubled, aided by the availability of eight cutting edges on CBN insert.
HFT tool holders feature a specially developed insert location for speedy and accurate exchange, while the monoblock design caters for turning, boring and facing with machine interface couplings available in HSK, VDI, ISO-PSC and DIN shanks. The double clamp insert system ensures higher stability of the insert with a direction-defined coolant/air supply through the holder.
In recent hard-turning trials, HFT CBN inserts were run at 150 m/min and 1.2 mm/rev to achieve over 1200 parts per insert. Previous methods at slower cutting speeds only achieved 100 components per insert.
Similarly, for finishing cuts, previous tool life was 100 parts per insert. However, HFT enabled this rate to be increased to 1600 components, with speed increases to 150 m/min from
120 m/min.
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Mastering the challenges of hard turning

The Kennametal KBH10 is a new uncoated PcBN turning insert that is claimed to offer high wear resistance and very low cutting forces.

As a result, Kennametal says that many customers are now enjoying double the tool life together with improved part quality.
KBH10 PcBN hard-turning inserts are designed to turn hardened metals up to 65 HRc, especially where very high surface finishes are required. Typical parts set to benefit include bearing journals, rings and pistons, and gear hubs, where dimensional tolerances of <4 μm or less are increasingly common, along with surface requirements better than Ra <0.4 μm. In one example, a well-known automotive manufacturer was able to more than double tool life, from 150 to 350 pieces per edge during an internal facing operation on a 140 mm diameter 5115 alloy steel bearing hub that was previously heat-treated to 62 HRc. A drive-shaft producer achieved similar results, increasing tool life from 250 to 450 pieces per edge when turning 58 HRc UC1 (similar to S53) steel on its vertical turret lathes, consistently maintaining a surface finish of 6 Rz while doing so. In each instance, a cutting speed of 180 m/min was used, with depths of cut averaging 0.15 mm and feed rates ranging from 0.22 to 0.32 mm per rev. Also, in each case the customer saved thousands of dollars annually in insert costs compared with its existing solution, while substantially reducing downtime due to tool changeovers, says Kennametal. For further information

Even better groove milling

Trouble-free precision groove milling in an easy-to-use format is what Sandvik Coromant says manufacturers are set to enjoy with the latest CoroMill 331 indexable-insert cutter.

New features include internal coolant and light cutting geometries for stable and secure machining.
The addition of internal coolant helps to regulate heat in the cutting zone for long and predictable insert life. This factor is especially beneficial in ISO M and ISO S materials (stainless steel and heat-resistant alloys), which exhibit poor thermal conductivity. Additionally, internal coolant aids chip evacuation, a key factor for groove quality and process security.
Trouble-free machining is further supported through the introduction of light cutting geometries. For ISO M and ISO S materials, L30 and L50 geometries replace the company’s existing assortment for good conditions/light applications and tougher conditions/heavy applications respectively. For ISO P (steel) and ISO K (cast iron) materials, M30 geometry now complements the existing assortment. M30 is designed for the delivery of secure machining where weak set ups and long overhangs are present.
Another factor underpinning process security is enhanced cutter rigidity. In applications where long overhang or elevated levels of vibration are likely, CoroMill 331 can be deployed with Silent Tools damped adaptors. Here, the shorter body of CoroMill 331 brings the cutting edge closer to the Silent Tools damping mechanism, providing yet more tool stability.
Sandvik Coromant says that typical parts to benefit include hour-glass valve bodies, aerospace brackets, flap tracks and steering knuckles, to list but a few. CoroMill 331 also offers high levels of versatility that render it suitable not just for groove milling, but parting, double half-side machining, shoulder milling, face milling, back-face milling, gang milling and circular interpolation.
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End mills aimed at tool makers

Pitched at the tool-making industry, Rainford Precision has introduced the series of HSB-S Unimax ball-nose end mills from Union Tool.

The range of small, two-flute, short-shank end mills are ground to an H4 tolerance of 0/-0.004 mm.
Designed for application with precision tool holders such as shrink-fit types, the HSB-S is offered with an overall length from 35 to 40 mm to minimise tool protrusion and maximise rigidity. Importantly, a key feature of the range is the ±0.003 mm tolerance of the ball-nose radius, which is intended to improve surface finish.
The HSB-S Unimax can be offered with a ball-nose radius of 0.1, 0.15, 0.2, 0.3, 0.4, 0.5, 0.75, 1, 1.5 or 2 mm, and a length of cut from 0.2 to 4 mm. Designated as a series for machining materials of 40 HRc and above, the tools feature HardMax coating technology and negative rake-angle geometry to provide a balance of tool hardness, heat-resistance and durability. The negative rake reduces as the radius transitions to the periphery, which is said to minimise tool deflection and generate mirror-finish surfaces.
HSB-S end mills can be applied to materials such as carbon, alloy, pre-hardened and hardened steels up to 70 HRc. Additionally, the HardMax coating enables the HSB-S to process copper, cast iron, titanium alloys and heat-resistant alloys.
For manufacturers seeking a long-necked version for reaching difficult-to-access surfaces, Rainford Precision offers the HSLB-S series. Available with a ball-nose radius from 0.1 to 3 mm, the HSLB-S range has a maximum clearance length of 20 mm with an overall length from 35 to 50 mm, depending upon the selected tool diameter.
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