Second Workstation Means Medical Specialists Can Double Output On Bumotec s181 Turn-Mill Centre

The s181 nine-axis turn-mill centre from Starrag Group company, Bumotec, is a compact and cost-effective multi-function machine targeted at medical and surgical instruments.

Importantly, the machine features a second, live tool workstation enabling up to 40,000 revs/min milling to complement the 90-position automatic tool-changer that serves the 11 kW, 6,000 revs/min main HSK-40 spindle.

This additional station effectively increases productivity by up to 40 per cent by enabling up to five driven tools to work on the rear side of one part while the main tool spindle works on another component. Integrated tool breakage monitoring also ensures optimum productivity levels are maintained.

In one instance, the production of a stainless steel surgical instrument is being produced in just four minutes compared with almost seven minutes on a single-station machine. Other examples include:

• The production of femoral balls in a single set-up – machining the cobalt chrome units from bar to a surface roughness of Ra 0.04 micron and a sphericity of 0.002 mm;
• Machining intervertebral implants in one piece from implantable peek with no burrs – including inserting x-ray marker pins without manual intervention – reducing cycle time by 22 per cent compared to a sliding head machine and producing the finished unit in 9.38 min compared to 12 min (without pin insertion);
• Producing modular hip joints from titanium (TiAl6V4 Grade 5) and turning and milling the cone to two and four microns, respectively, in the same set-up compared to the previous process of using separate turning and milling machines; and
• Machining hip stem rasps from 48 mm diameter stainless steel bar in a cycle time of 1.4 hours compared to 2.30 hours on a standard vertical machining centre.

Derived from the Bumotec s191 linear CNC turn-mill centre, a proven solution that utilises linear drives and boasts high-level thermal stabilisation to achieve 2.5 microns machining accuracies in the six-sided, complete machining of workpieces, the s181 is multi-functional turn-mill centre designed for the single-set-up, complete machining of complex and high-precision workpieces. With water-cooled axes, the machine has a 90-tool magazine, including grinding discs up to 80 mm diameter, which accommodates all machining eventualities.

With a footprint of just 3.5 m2, the machine can handle bar of 32 mm diameter and, being of modular design, can be equipped with a range of productivity-gaining options including auto part loading to complement the choice of parallel jaw vices, tailstock, collet system or multiple workholding units.

The s181’s development was focused on the efficient production of medical, orthopaedic and dental components, as well as surgical instruments, but the machine is equally at home in all micro-mechanic industry sectors including watchmaking and jewellery.