The s181 nine-axis turn-mill centre from Starrag Group company Bumotec is targeted at medical and surgical instruments.

It is available from Birmingham-based Starrag UK Ltd (www.starrag.com).

A particular feature of the machine is its second live-tool workstation (for milling at up to 40,000rev/min). Complementing the 11kW 6,000rev/min main HSK-40 spindle, this increases productivity by up to 40%, principally by enabling up to five driven tools to work on the rear side of one part while the main spindle works on another component. Integrated tool breakage monitoring is also featured.

Notable applications include the production of femoral balls in a single set-up — machining the cobalt chrome components from bar to a surface roughness of 0.04Ra and a sphericity of 0.002mm.

In another example, intervertebral implants were machined in one piece from implantable PEEK with no burrs; the process even included inserting X-ray marker pins without manual intervention. Compared with a sliding-head machine, the s181 reduced the cycle time by 22%, producing the finished unit in 9.38min.

Starrag also reports producing hip stem rasps from 48mm-diameter stainless-steel bar in a cycle time of 1.4hr, compared with 2.3hr on a standard vertical machining centre. Derived from the Bumotec s191 linear CNC turn-mill centre, the s181 features water-cooled axes and a 90-tool magazine that can also house grinding discs up to 80mm in diameter.

The machine has a footprint of 3.5m² and accommodates bar up to 32mm in diameter; and being of modular design, it can be equipped with a range of options, including automatic part loading.

While the s181’s development was focused on the production of medical, orthopaedic and dental components, as well as surgical instruments, the machine is equally at home in micro-mechanical sectors such as watch-making and jewellery.