Insert accommodates low and deep cut depths

By combining two different geometries on the same insert, Walter has created the NRF indexable insert for simultaneous heavy duty rough- and finish-turning applications in the same setup.

The insert can be applied on both low- and high-alloy steels and with the same tool, effectively halving the number of geometries users may need.

In addition, because NRF features a strengthened double groove at the main cutting edge, the doubled chip compression generates short chips.

The V-shape chip-forming area at the cutting radius leads to optimum chip breaking at low depth of cut.

Available in five basic shapes - CNMM, DNMM, SNMM, TNMM and WNMM - and in a variety of Tigertec coatings, NRF inserts can accommodate machining at low (0.8mm) and deep (15mm) cut depths, and cutting forces can be reduced because the curved cutting edge generates a soft flow of swarf.

Cutting-tool PIPs pay dividends for subcontractor

Sandvik Coromant has helped a Dutch CNC turning and milling specialist to cut cycle times, create extra capacity and see-off competition from developing economies.

The growing threat from competition based in developing economies led Abrahams Metaalbewerking to consider participating in productivity improvement programmes (PIPs) around six months ago.

PIPs helped Sandvik Coromant to save its European customers more than EUR70m (GBP60.1m) in 2007.

A PIP improves profitability by increasing machining efficiency, reducing individual unit cost and eliminating unnecessary time and material waste.

Each PIP is tailored specifically to individual customer needs and encompasses many pre-defined steps: bottlenecks and areas of potential improvement are identified; extensive data is gathered and assessed on targeted jobs; potential solutions are examined; reports are run to determine possible benefits; solutions are tested on the shop floor; the customer chooses which solutions to implement; operators are trained on new tooling and processes; and follow-up visits are scheduled to ensure full realisation of savings.

Abrahams Metaalbewerking handles batch sizes as large as 10,000, manufactured from a variety of materials on its range of high-specification Okuma CNC turning, milling and turn-mill machines.

The company turns parts of between four and 250mm diameter, while milling capacity is 1000 x 500 x 400mm.

Reduced or unmanned staff at night and weekends provide 24/7 operations.

The company wanted to accelerate machining times but without buying additional machines or employing more people.

One of the biggest gains was achieved by running pre-release tests using Sandvik Coromant's new GC1125 and GC1515 light turning grades.

Sandrino Rizzo, sales engineer for Sandvik Coromant, said: 'We used GC1125 on AISI304 austenitic stainless-steel components and GC1515 on ST52 steel.

'Both gave a much more reliable process and doubled throughput of turned products.' Based on the latest developments in cemented carbide and coating technologies, the new GC1125 and GC1515 inserts are ideal where applications demand a sharp cutting edge with high edge-line integrity in light turning.

Typical applications include interrupted cuts, machining into shoulders and internal finishing.

GC1125 provides high edge sharpness for secure, burr-free machining of stainless steels and gives the toughness needed for intermittent cuts.

It also performs well in sticky materials and is a good choice for vibration-free machining.

The improved edge line strength and sharpness maintain good chip control, surface finish and tool life at lower feed rates.

GC1515 grade for steel machining combines wear-resistant coating and a tough edge.

This provides the potential to produce more components per cutting edge while maintaining close tolerances, with a minimal number of off-set corrections.

Richard Cornet, who acquired the company in January 2007, said: 'The next step was to improve machine feeds and speeds to create shorter overall lead-times.

'From the results of four PIPs implemented in a short period of time, we managed to gain an extra 600 hours of machine capacity.

'On average we now have actual machine cutting time of 130 hours per week - up from 90 hours previously - a gain of 45 per cent.'.

Corocut XS inserts from Sandvik Coromant feature a front angle increased

Corocut XS inserts from Sandvik Coromant feature a front angle increased to 20deg to improve component quality in parting operations.

The main application is in sliding head machines without a sub-spindle.

Here, customers can achieve higher productivity and better component finish as the insert edge design offers pip and burr-free surfaces.

The inserts are precision ground and available in grade GC1025 for material groups ISO P, ISO M and ISO K.

When parting with a sub-spindle it is more productive to use a straight cutting edge as this is a more stable parting method and will generate the best surface finish.

However, when parting without a sub-spindle it is recommended to use an insert with a minimum insert angle of 15deg to minimise the risk of burr and pips on the component.

Corocut XS parting geometry is designed specifically for precision-made components.

The geometry makes the chip narrower than the groove, which provides chip control.

Parting-off inserts are available in widths down to 0.7mm.

Sandvik Coromant's Corocut XS is a tangentially mounted system for precision machining using sliding head machines.

As well as parting-off, the system is available for a number of other external turning operations, including grooving.

Grooving inserts are available in 0.5, 1.0, 1.5, 2.0 and 2.5mm widths.

In terms of toolholders to accompany Corocut XS, parting and grooving sets high demands on accessibility since the inserts are often fed deep into the material.

This means narrow machining and therefore the length of the tool increases in line with the diameter.

Tools and tooling systems with high stability are therefore very important.

For best economy, Sandvik Coromant recommends its QS holding system as a productive alternative to conventional toolholders when used on sliding head machines.

In comparison with the 12 steps required when changing conventional one-piece toolholders, the QS system offers an efficient two-step set-up procedure to reduce downtime.

The single screw release design of the QS tool holder will reduce toolchange times by around 66 per cent, while the spring-loaded wedges ensure quick and safe extraction and reduce the risk of dropping the holder.