One-hit turn-milling halves cycle time and eliminates inter-machine handling
Looking at the cuboid aluminium components produced for medical diagnostic equipment by subcontractor AES Precision Engineering, one would think they were milled, drilled and tapped on a machining centre rather than a lathe; indeed they used to be, from sawn billet in two separate operations on a pair of 3-axis vertical-spindle machines in a total cycle time of 12 minutes.
Since April this year, they have been machined complete from round bar in one operation in an Italian-built Biglia B565-YS 6-axis turn-mill centre supplied by UK agent Whitehouse Machine Tools. Program run time has more than halved to 5.5 minutes, accuracy is improved and there is no handling between machines or work-in-progress on the shop floor, significantly reducing the cost of production. Only two turning tools are in the 12-station turret for facing the bar end and for parting off, the remainder being axial and radial driven tools.
Mark Wilson, a director of the family-run subcontracting firm commented, “We have been making these parts for years, during which time the volume has gradually increased to 1,000 per month.
“So we needed to find a more efficient way of machining them. From visits to trade shows we were aware of the powerful prismatic machining capabilities of the latest CNC turning centres.
“We asked four potential suppliers to offer a turnkey package based on production of the aluminium medical part. Whitehouse demonstrated the best process in terms of quality, capability and cost on a Biglia lathe at its Kenilworth technical centre.”
Key attributes of the twin-spindle, single-turret machine that secured the purchase are a full (rather than indexed) C-axis on the counter-spindle, essential for this particular job; and a genuine Y-axis, so there is no need for time-consuming and less accurate interpolation of the X and C axes to achieve the prismatic shape of the component.
Mark also made the observation that there are no bad machine tools these days, albeit some are more accurate and reliable than others, and that what really makes the difference is the level of service back-up from the supplier. In this respect, Whitehouse Machine Tools is judged to be exemplary based on its handling of the enquiry, applications engineering input to date and feedback from other users of machines it has supplied.
Production engineer Trevor Orman added, “The quality of the Italian lathe is high for this class of machine, costing under £200,000 with tooling.
“Although tolerances on the medical part are fairly open at 0.1 mm, the Biglia repeats to within microns, which means we no longer have to chase tolerance all day as the temperature varies on the shop floor.
“The machine’s accuracy will also be invaluable for production of more tightly toleranced components and its rigidity means that tool wear is noticeably lower than on our other lathes.”
The existence of the turn-mill machine has already brought in a new contract for the manufacture of 316 stainless steel automotive components that AES Precision Engineering could not have quoted for previously.
The subcontractor intends to transfer jobs from other lathes to the Biglia to enable more economical production. It is also looking for further bar auto work to a maximum of 70 mm diameter by up to 560 mm long, preferably involving runs above 1,000-off, to fill the machine’s capacity.
Founded in 1987 initially to manufacture components for the medical industry, AES Precision Engineering has since expanded into the automotive, leisure, marine, cosmetics and defence sectors, including the production of complex parts for drones and reverse-engineering of replacement parts for production lines. In 2004 it moved to the present, larger premises on the New Street Farm estate in Ashford, Kent and has invested heavily over the years in a range of new machining centres, including 5-axis models, and multi-axis CNC lathes.