At the time, one component in particular was being manually honed in four operations. Company director Richard Pollard comments: "It is never easy to change a process that has been in use for over 20 years and when cost per part needs to be kept down, you cannot throw money at problems to find solutions. Investment in new production machines has to be at the right price."
Pollard took its need for a cost -effective solution to Delapena's technical services manager Paul Lane who helped the subcontractor to configure a repeatable cell for achieving the required quality, based on horizontal honing rather than the more expensive vertical process.
Pollard's best solution was to complete all the roughing on its three Delapena E1000s, using the machine's short stroke facility and controlled encoder and ballscrew expansion. The ability to expand the tool in increments as small as 0.0001 mm/sec, when required, gives a level of control usually associated with lapping.
The challenging component, which has a 24 mm diameter by 100 mm long blind hole with several rings of small cross-holes along its length, had to be honed to within 8 micron on geometry. However, simple fixtures make it easy to switch to machining other components and, with a modified standard tool, the consumable element of the manufacturing cost per part is minimised.
Image: Delapena met the challenge at Pollard Engieneering
Controlled short stroking keeps the blind end parallel while a ratio of long strokes keeps the whole bore within tolerance over the entire batch. Using CBN superabrasive, stock removal of 75 to 100 micron is efficient and with minimum abrasive wear.
Pollard Engineering supplies high precision machined components primarily to the mining, oil drilling and aerospace industries. Batch sizes range from 1 off to 10,000 off. Beryllium-copper, ToughMet, titanium, Inconel and Duplex steels are some of the exotic materials processed by the ISO 9001:2000-accredited company. It employs 52 people on day and night shift in its 14,500 ft2 factory in Tewkesbury.
First published online