Unstable milling processes produce chatter, vibration and runout that can destroy tools and ruin workpieces. In the quest for higher metal removal rates and increased part production, shops look for ways to elevate machining performance and eliminate any parameters that can introduce negative effects. The right choice of end mills can propel that quest for productivity into profitability – and tool design holds the key to taking full advantage of today's powerful milling machines without performance problems that curtail output.
On the list of troublesome milling issues, chatter ranks high, but identifying its source can require careful detective work. Overall, chatter can cause many woes, including the inability to achieve good surface finishes and work at high cutting speeds. The vibrations that cause chatter can stem from setup problems, including improper toolholding and poor-quality toolholding systems.
In some cases, however, the harmonics produced by the tools themselves can lead to chatter and pose a dramatic challenge to material removal. Most end-mill designs use symmetrical flutes with helix, rake and relief that match from flute to flute. This more-nearly conventional approach presents drawbacks because the highly regular impact of its cutting edges can lead to chatter.
Geometry that varies from flute to flute can go a long way toward promoting cutting stability, even at heavy depths, by squelching the resonant vibrations that stem from harmonic cycles. For example, our first-generation Niagara Cutter™ Stabilizer™ end mill varies tool geometry so each flute varies from the others.
To take the advantages of variable geometry to its fullest potential, however, would require production capabilities that tool manufacturers lacked – until recently. Today's production equipment and special programming approaches enable the creation of end mills with patented fully variable designs, including continuously variable rake, relief and helix for each flute. At the same time, new carbide compound formulas make the tool material itself more stable and less prone to deflection and runout, even when the tool is fully engaged.
The combination of continuously varying asymmetrical flute geometry and newly re-engineered flute shapes produces the edge strength and long tool life of Stabilizer™ 2.0, with twice the MRR, chip load capacity, feed rates and productivity of the product's first generation, even in heavy roughing cuts on 50-taper milling machines. The special new flute design, with individualized flute cavities for each tool and each size, squelches chatter because it eliminates the vibrations that produce it while simultaneously improving chip evacuation.
Stabilizer™ 2.0 targets aerospace, power generation, automotive and general engineering applications including slot milling, side-mill roughing and finishing, face milling, high-performance optimized roughing, pocketing and ramping, with two tool series, each created to work with specific materials. The ST430.2 series focuses on steels, alloy steels, copper alloys and cast iron, while the ST440.2 HT series takes on stainless steels, steels with hardness values up to 42Rc, titanium and Inconel®. This universal end mill eliminates the need for shops to invest in an ever-increasing tool inventory to complete projects in wide-ranging materials and with traditional and advanced machining methods.
