Since its unveiling at AMB 2018, the High Dynamic Turning (HDT) process, which has received numerous innovation awards, has made waves all over the world of machining. By using the milling spindle in turn-mill centres, the cutting angle of the dynamic FreeTurn tool can be adjusted 360° for optimal use in every position of the workpiece. This creates several opportunities. First, flexible machining of almost any workpiece contour is possible. Also, chip breaking is optimal. And it is even possible to achieve higher feed rates and tool life with maximum stability in addition.

Dr Thomas Ledermann, production manager for special tools at the Ceratizit tool manufacturing location in Besigheim, explaions: "Here in Besigheim we produce tools of the highest quality and use highly optimised processes for this. The possibilities offered by High Dynamic Turning and FreeTurn really appealed to us. Therefore, we decided to implement the turning process to test whether it really does what it claims.”


Read Machinery's June 2019 article about Ceratizit's HDT and FreeTurn tools

The possibility of tooling reduction was a particular benefit, as a single FreeTurn indexable insert can be used for various turning applications. For Ledermann, this fact alone is a good argument for switching to HDT, as it saves considerable tool costs.

“The most obvious advantage of HDT and FreeTurn are the tool cost savings. Where we conventionally needed several tools for roughing, finishing, contour, face and longitudinal turning, we now only need one dynamic FreeTurn tool,” says Paul Höckberg, product manager for turning at Ceratizit, who assisted the changeover at Besigheim. However, it was quickly realised that this is not the only advantage. In terms of process speed and energy efficiency, too, the dynamic turning process was ahead of conventional machining.

Höckberg again: “The initial machining at Besigheim was conducted on a DMG Mori CTX beta 1250 TC as it fulfills all the requirements for turning in a highly dynamic manner. This machining centre is widespread on the market and HDT ready, confirming that many manufacturing companies are able to use our FreeTurn technology.

The component chosen, a base body of an indexable insert drill, was then optimised and programmed using the Siemens Sinumerik 840d controller and a 5-axis simultaneous cycle software from Open Mind – the results proved to be astonishing.

Says Ledermann: “As expected, we were able to reduce the number of tools required. Instead of three different tools, we now only manufactured the component with one FreeTurn tool. We processed the component with a cutting speed of VC 220 m/min, a feed rate of f0.48 mm/rev and an infeed depth of ap 4 mm. For finishing cuts, the surface speed increased to 400 m/min. FreeTurn proved itself to be a far superior alternative to our conventional tools.”

Höckberg was also amazed by this result: “We knew FreeTurn was good. However, we would never have thought it possible to drive such enormous cutting speeds in mild steel (X40CrMoV51).”

And in another comparison to the previous conventional processing clearly shows that the switch to HDT and FreeTurn has paid off. "We were able to save 2.25 minutes of production time, €3.53 production costs and 0.42 kWh of energy per component.”

Due to this positive result, High Dynamic Turning and FreeTurn will be more broadly applied at Besigheim. Programming is carried out using the Siemens NX CADCAM software, which is also ideal for HDT. “We are already looking forward to gradually converting our production to High Dynamic Turning and FreeTurn," concludes Ledermann. “This way we can secure a significant competitive advantage.”