Integrated Grinding And Polishing Means A Fine Finish With The Bumotec Turn-Mill Centre

The ability to finish-machine a chrome cobalt femoral head in a single set-up – including grinding of the spherical shape to a sphericity of 2.5 microns and precision polishing to Ra 0.05 – is making the Bumotec s191 seven-axis turn-mill centre a machine of choice for medical manufacturing.

Higher productivity/lower cycle time advantages are gained by producing such complex shapes in a single cycle on the s191 compared to traditional multiple set-ups across a number of machines due to, for example, the quick change over between the different sequences, less inter-process part handling and reduced floorspace requirements.

Starting with a plain bar, the s191 performs the sequence of six-sided operations on the femoral heads, beginning with turning and milling, then grinding and polishing, to complete the components in a single set-up thanks to the machine’s innovative dynamic correction capabilities, the effectiveness of its Fanuc linear motor and the use of Renishaw contactless part probing techniques.

The components are efficiently machined in both high-mix small batches as well as large-volume serial production.

The capabilities of the s191, from Starrag Group company Bumotec SA, are set to be showcased next year (from February) at the Advanced Manufacturing Research Centre with Boeing in Sheffield. Here, the machine – which is available in bar capacities of 32 mm, 50 mm and 65 mm - will be demonstrating its ability to benefit the machining of a range of ‘micro parts’ in a variety of materials for industry sectors including micro-mechanics, aerospace and luxury goods, as well as medical manufacturing.