German cutting tool and insert manufacturer Paul Horn, which offers 25 000 standard products and more than 150 000 special tooling solutions has unveiled a new boring bar with adjustable damping, which will be shown carrying a grooving insert. A long overhang can cause a turning tool to oscillate when boring internal geometries. In addition to causing chatter marks on the surface of the machined component, the vibrations can lead to a significant reduction in tool life. For unfavourable length-to-diameter ratios, even damped boring bars may vibrate under certain conditions.

To address this problem, Horn has developed a boring bar that can be set to match the oscillation amplitude during machining. Precise adjustment enables vibration-free turning, resulting in better surface quality and a significant increase in insert life.

The damping element, a carbide rod supported in O-rings, is adjusted from the outside by turning a screw to fine-tune the pre-tension of the rings. This allows the boring bar to be set accurately to minimise the vibration that is predicted to occur during a machining cycle.

As standard, Horn offers the boring bars from stock in length-to-diameter ratios of 5:1 and 8:1. Higher ratios are available as special tools. In the case of grooving, Horn offers the S224 double-edged system. The manufacturer’s BK 224 cassette system ensures a stable interface between the boring bar and grooving insert. To increase process reliability further, the tools have an internal coolant supply.

For further details visit www.phorn.de