DR reamers size blind- and through-hole diameters

Horn Cutting Tools

DR reamers

Horn Cutting Tools will introduce tool systems for reaming, grooving and high-feed milling, at Mach 2010.

In addition to exhibiting on its own 120m2 stand, the company will provide tooling in support of live demonstrations on the DMG and Mori Seiki stands.

Horn developed the DR range of high productivity and high-precision insert-based modular reamers for rapid sizing of blind- and through-hole diameters from 11.9 to 100.6mm.

The reamers are produced under licence from the Swiss-based boring and reaming specialist Urma AG.

The system combines high performance with excellent tool life.

DR provides cycle-time improvements of 10 or 11 times.

Using a single cutting grade, they deal effectively with different material types without loss of performance.

A key feature of DR reamers is the use of a narrow, high-rigidity ring-type cutting element, produced using either micrograin carbide (coated and uncoated) or cermet.

The cutting element is 4.3mm thick; most reamer wear occurs within 2mm of the leading edge, while guidance is normally satisfactory with 4mm total thickness.

The thin section also reduces friction and chip evacuation and allows tighter manufacturing tolerances to be maintained.

For applications that require additional guidance, the DR system includes holders equipped with guide pads.

A comprehensive range of holders and system adaptors is now available.

Holders for diameters from 11.9 to 35.6mm are available in two different lengths, for aspect ratios of three-to-four- and six-to-eight-times hole-diameter.

All are equipped for through-tool coolant supply.

Diameters from 35.601 to 100.6mm are catered for by a modular shank/insert holder system that offers integrated run-out adjustment capability to maximise accuracy.

Attachment of the cutting element to the tool holder involves HSK-style mating tapers for positioning repeatability within 0.004mm.

Ample face-to-face contact and multiple screw clamping ensure maximum system rigidity and the high repeatability makes for rapid insert exchange.

As well as the DR holders, adaptors allow existing proprietary exchangeable head-reaming holder systems to use the DR reamer technology.

This offers a cost-effective upgrade path as most of the performance advantages of DR are maintained.

Horn Mini with Sintered Chipbreaker is a new series of sintered inserts for the Mini system.

Application-specific chip-breaker geometries provide a significant advance in cutting performance compared with conventional plain ground inserts.

Especially on internal machining applications in 'difficult' materials, the chip-breaking capability enhances productivity, finish and tool life.

The existing Mini tool system has a proven reputation for grooving, boring, chamfering, threading and axial grooving.

These diverse applications are significantly expanded by the new range.

In comparison with a conventional ground insert, the sintered geometries produce smaller, discontinuous chips, exhibit high resistance to temperature and low coefficients of friction.

Sintered chip breakers with ground cutting edges and corner radii are available in the geometry forms .D for grooving and profiling and .R for profiling and boring.

The key feature of geometry .D is low cutting forces assisted by the continuous, uniform chipping angle.

This form also supports lower feed rates.

The geometry .R with corner radii of 0.2 and 0.4 is designed for higher feed rates with low cutting forces and exhibits good chip control.

Inserts with .D geometry for grooving are available in 11 sizes for groove depths from 1 to 8mm in entry holes of 8 to 20mm diameter.

There are six .R geometry inserts available for boring in bore holes with 7.8 to 15.5mm diameter.

Bore-hole diameters of 18 and 20mm are covered by the Type 18P inserts.

In addition to the geometry forms .D and .R, they are also available in the form .00 for machining stainless steels with full radius 0.9/1.1 and 1.5mm width.

Non-standard widths are available to special order.

The tool-holder interface for the sintered inserts features a location section brazed to a low-vibration carbide shank.

The symmetrical prism mounting of inserts with .D and .R geometries enables clockwise and anticlockwise versions to be fixed to the same holder.

Type P inserts, designed for larger groove depths, require clockwise and anticlockwise toolholders due to the asymmetrical prism mounting.

The three-point support with the defined gap dimension between carbide head and insert in each version guarantees a high-precision and secure connection.

Horn designed the milling cutters of the Horn DAH system for tool- and mould-making involving roughing with high feed rates and low cutting depths.

The sophisticated geometry of the triple-edged inserts ensures favourable distribution of the cutting forces, by directing the cutting forces in the axial direction, reducing the spindle load in shear and offering significant productivity advantages.

High-feed milling strategies generally allow suitable tooling to absorb very high loads using tooth feeds of 1mm per tooth, comparing favourably with the relatively low cutting depths of 0.5 to 0.8mm for conventional tools.

Horn DAH milling cutters provide significantly better values.

Their special cutting geometry, which combines 'soft' cutting with fast plunging, enables cutting depths up to 1.2mm, providing a clear advantage over many competing tools.

Depending on the material, feed rates up to 3mm/tooth can be achieved for a maximum cutting depth of 1.2mm.

The triple-edged milling inserts are currently available in the carbide grade SA4B.

This is distinguished by particularly high-wear resistance for milling steel and cast materials.

The titanium nitride (TiN) coated holders with internal coolant supply are available as end mills, with Weldon toolholder and as industry-standard threaded connection cutter with the MD holder design, already tried and tested in the DA system.

With cutting-edge diameters of 20, 25, 32 and 40mm, the new DAH milling system expands the product range of the Horn company for tool making and mould making in the direction of larger diameters and higher feed rates.

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