Endmill Cutters Overcome Surface-Finish Issues
The DHC (Different Helix Cutter) Inox series of solid-carbide four-fluted endmill cutters have been developed to overcome problems associated with vibration and poor surface finish. These problems are mainly caused from the build-up of harmonic oscillation when circumferentially milling materials such as titanium, nickel-based alloys, stainless steels and short-chipping aluminium. The cutter is ground with different helix angles applied to consecutive flutes of the tool, reducing vibration under heavy cutting by creating the effect of a continuously modified pitch to the cutting edge.
Due to the geometry created in the DHC Inox endmill, the same tool can be used for both rough and finishing passes at very high rates of feed per tooth. By creating an uneven pattern of helix angles set at 41 and 44deg on sequential cutting edges of the tool, cutting forces are also reduced as any chips produced will have different cross-sectional areas. The DHC Inox range of tools are available between 4 and 20mm diameter, and have internal coolant feed that outlets through radial ports. This feature makes the cutters suitable for plunge milling, production of extremely thin, dimensionally stable webs, as well as deep slots in a ratio up to double the diameter of the tool.
Each tool is produced from micro-grain carbide with a wear-resistant and temperature-stable PVD coating. The rake angle is large, which also helps to reduce cutting forces and, by optimising the chip void, evacuation of material from the cutting zone is well catered for. A short version of the cutter range is also available that, due to its increased rigidity, allows up to a 40 per cent increase in the applied feed rate. On a recent machining trial carried out on stainless steel, a DHC 1550C slot endmill 12mm diameter was run at 90m/min with 18mm depth of cut at a feed rate of 290mm/min using through-the-tool coolant supply to create a deep, very thin-walled slot.
Due to the geometry created in the DHC Inox endmill, the same tool can be used for both rough and finishing passes at very high rates of feed per tooth. By creating an uneven pattern of helix angles set at 41 and 44deg on sequential cutting edges of the tool, cutting forces are also reduced as any chips produced will have different cross-sectional areas. The DHC Inox range of tools are available between 4 and 20mm diameter, and have internal coolant feed that outlets through radial ports. This feature makes the cutters suitable for plunge milling, production of extremely thin, dimensionally stable webs, as well as deep slots in a ratio up to double the diameter of the tool.
Each tool is produced from micro-grain carbide with a wear-resistant and temperature-stable PVD coating. The rake angle is large, which also helps to reduce cutting forces and, by optimising the chip void, evacuation of material from the cutting zone is well catered for. A short version of the cutter range is also available that, due to its increased rigidity, allows up to a 40 per cent increase in the applied feed rate. On a recent machining trial carried out on stainless steel, a DHC 1550C slot endmill 12mm diameter was run at 90m/min with 18mm depth of cut at a feed rate of 290mm/min using through-the-tool coolant supply to create a deep, very thin-walled slot.
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