Making use of standard solid- carbide end mills (or indexable-insert face mills) and the complex motion available from simultaneous five-axis machining centres, it is possible to produce deep cavities from solid material in a very short space of time. WNT and Open Mind have also worked together on a machining strategy known as helical drilling.
Typical cutting data for a 6mm-diameter circular-segment cutter with three flutes machining tool steel (1.2312) is 300mm/min surface speed, 16m/min feed rate, an axial depth of cut of 1.5mm, and a radial depth of cut of 0.2mm.Ĭircular-segment cutters can also machine hard-to-reach planes, such as deep pockets in an airframe - and the same cutter can be used to blend the corner radius in a pocket. With a circular-segment cutter, this step-over can increase to 1.5mm, and the surface finish can be improved to 0.46µm Ra.
With a typical ball-nose cutter, the step-over distance (or axial depth of cut) would be 0.5mm, and the surface finish would be about 1.22µm Ra. The key feature of these end mills is the large radii in the cutting area, simulating a ball-nose cutter with a cutting diameter between 12 and 3,000mm and allowing large step-over distances to be used. There are four types of cutter in WNT’s range of circular-segment cutters - barrel shape, oval form, taper form and lens shape.
The benefits resulting from this combination of CAM software and WNT tooling include: increased step-overs while generating the same theoretical scallop height improved cutting performance in difficult-to-reach areas of a component significantly greater machining efficiency reliable finishing strategies and process security and reduced thermal deformation. The HyperMill Maxx user interface simplifies these complex movements, making them easy to program, and maximises the cutter geometry to present the cutter at the optimum orientation to the workpiece at any point on the cutter path. However, the cutters have to be moved simultaneously in five axes in a sweeping pendulum-like motion over the workpiece. The large radii ground on these cutters (up to 3,000mm) allow much greater step-overs between cutter paths to deliver reduced cycle times. Open Mind’s tangent plane machining strategy was developed with circular-segment cutters in mind. The worlds of CAM and tooling have combined to deliver significant cycle-time savings across a wide range of machining applications, including mould-and-die, turbine blades, impeller blades and blisks.Ĭombining Open Mind’s ( HyperMill Maxx tangent-plane machining strategy with ‘circular-segment’ cutters (barrel milling cutters) from Sheffield-based WNT (UK) Ltd ( milling cycle times can be cut by as much as 90% when semi-finish and finish milling on five-axis simultaneous machining centres.įurther benefits include reduced loads on the machine spindle and improved surface quality.