Westwind
Westwind Air Bearings has been supplying high-speed air bearing spindles to the printed circuit board (PCB) manufacturing and the precision machining industries for over 50 years. Spindle speeds have steadily increased in this time, from 80,000 rpm in the 1960’s to nearly 300,000 rpm in recent years, due to the continuing requirements for smaller tool diameters and improved productivity. Drill diameters as small as 75 microns are already used in cutting edge PCB manufacturing facilities, with 50 micron drills under evaluation for next generation electronic products. Due to the low vibration and smoothness of rotation, together with minimal bearing friction, air bearings are ideally suited to these application areas.
However, for these really small drill diameters even 300,000 rpm is not fast enough to achieve the correct peripheral cutting speed for soft materials. In response to this requirement, Westwind has been developing a brand new ultra high speed spindle with a maximum speed of between 330,000 and 350,000 rpm, dependant on application. As part of the FP7 European funded IntegMicro micro machining project, Westwind has used advanced non-ferrous shaft materials together with the latest permanent magnet DC motor technology, to produce a robust spindle that has an enormous speed range, being capable of running right down to 15,000 rpm for the larger diameter tools. Special 2 mm and 3 mm diameter tool-gripping collets have been designed capable of withstanding the enormous rotational forces induced at full speed, whilst still producing tool tip dynamic runout of less than 5 microns.
Typical materials that can be machined include brass, aluminium alloy and copper, as well as PCB composites. With diamond tooling, surface roughness well below 10 nanometers is achievable (using aluminium alloy) and prototype spindles are already on test at Cranfield University in the UK, on their new 6-axis ultra compact micro-machining centre. Testing is also in progress with two precision machine tool companies in Europe.
Likely micro machining application areas for this spindle include the precision optic, medical and watch making industries where high productivity and excellent surface finish are of paramount importance.
Westwind Air Bearings
Holton Road, Holton Heath, Poole, Dorset
BH16 6LN, United Kingdom
Tel: +44 1202 627200
Fax: +44 1202 627202
Email: wwinfo@gsig.com
Web: www.westwind-airbearings.com