Corner cutter Mastering 90-degree milling

Shoulders, slots, edges, pockets, and cavities: Where right angles are involved, corner cutters are usually not far behind—at least in machining. But as is often the case, the devil is in the details. That's why Iscar offers specialized solutions for 90-degree machining.

Corner milling cutters are perhaps the most commonly used milling tools. They are used by operators to create shoulders, slots, edges, pockets, and cavities. The choice of a suitable model is essential, as the properties of each variant are as diverse as their fields of application. Cutter type, cutting geometry, and specific tool configuration are just three of the adjustments manufacturers use to tailor their tools to a particular application area.

The right configuration depends on the material, removal behavior, desired precision, required surface quality, and the individual characteristics of the machine being operated. For instance, solid carbide (VHM) cutters offer very high machining accuracy, while indexable insert concepts (WSP) excel when working under high loads and in terms of cost-effectiveness. However, the geometry of the WSP also has a decisive influence on the overall performance of the tool.

To meet the demands of the industry, Iscar has been continuously refining its portfolio for more than 30 years, pursuing various approaches in the process.

Since its introduction in the early 1990s, the tool manufacturer has continuously developed its Helimill series. A special feature of the product family: helical positive indexable inserts. The rake face and helical flank (relief) form a highly positive cutting edge in Helimill. This results in significantly reduced energy consumption and a very smooth cut. With the Helimill concept, Iscar further emphasized the design of WSP in its development work.

Rectangular or square WSP differ greatly in their properties from rhombic or triangular counterparts. Their shape determines, for example, the number of usable cutting edges. Additionally, square or triangular WSP are wider than rhombic forms and provide enough space for a larger central hole—and thus larger clamping screws. This allows the insert to be securely attached to the tool body, but this configuration also limits the minimum diameter of the cutter, which in turn can reduce the stability of the tool.

Rhombic inserts, on the other hand, offer a harmonious combination of cutting edge length, different corner radii, approach possibilities, and insert strength. The only drawback: the shape allows only two cutting edges. A double-sided design of the WSP partially compensates for this disadvantage but also brings limitations. The two-sided configuration influences the clearance angle and increases the axial rake angle of the cutter in which the insert is mounted.

Successful tool concepts are precisely tailored to the requirements of the application areas for which they were developed. Accordingly, Iscar's product portfolio is broad.

Three cases, three specialists

With the Neo-Logiq campaign, Iscar responded to the growing demand for fast and productive solutions for the challenges of the machining industry.

For roughing, semi-finishing, face, and corner milling of steel and cast iron, Iscar introduced the Neodo-S890 series. The shape and stability of the robust and double-sided WSP are achieved through a special sintering process. The square profile provides the user with a total of eight helical cutting edges—four on each side. The combination of a positive radial and negative axial rake angle promises a consistent cut with low energy consumption—especially in applications with interrupted cuts or varying machining conditions. Thanks to its wiper, Neodo produces very high surface finishes. The dovetail clamping securely connects the WSP to the shank. This makes Neodo an effective and economical solution for face milling on shoulders, for example, and wherever access and space are limited by clamping devices.

For users aiming for maximum productivity, Iscar developed the 90-degree Helido Trigon tools. These tools have a double-positive cutting geometry: meaning two positive rake angles—both axial and radial. Although the cutter with its triangular WSP has only six cutting edges, the specific configuration offers a higher number of teeth than comparable tools. This allows for very high feed rates and great productivity.

The tool is suitable for roughing on machines with low torque and high speed. Typical application areas include shoulder and slot milling, side grooves, and bevels.

With the triangular indexable inserts of the Heli3Mill cutters, Iscar completes its range for 90-degree machining. The product group features particularly sharp cutting edges and polished rake faces, making it designed for the machining of aluminum alloys and other non-ferrous materials. The special chip formers ensure very good chip control and enable high surface finishes.