You may not be able to fit a square peg into a round hole but Cheltenham based Apperley honing can certainly polish the inside of an oval tube to a surface finish of 0.15mm Ra.
Apperley Honing’s twin-spindle honing machine, the brainchild of Apperley’s MD Charles Sanders, has been designed to allow the simultaneous honing of two components rather than just one, leading to a potential increase in productivity in the precision honing market.
Sanders explained that the new machine is based on the old single spindle chassis honing machines but that the biggest change is that it is specifically designed for the contour honing process, instead of the polishing process used on single stainless steel tubes.
‘Honing used to be based on heavy industries,’ says Sanders, ‘but now we’re designing for pharmaceutical and semiconductor applications.’
‘We understand the honing process and put together a rough “back of a fag packet” design,’ adds Sanders. ‘Then we handed it over to Wulstan Designs, who did the rest.’
The result is a honing machine that has reduced set-up time due to the addition of a docking feeder, and incorporation of a pivoting drainage cradle to help with the expulsion of honing oil at the end of the process.
The tapered docking feeder is said to help automate set-up by guiding the honing heads and drive shafts to mate with the tubes to be polished.
The first machine in the twin-spindle range is the 17 metre long ‘J8’, with a 7-metre stroke, which on each operation can accommodate two 6-metre random lengths, within the core diameter range of 50 to 120mm.
Whilst designed and developed for machining thin-wall stainless steel for the semiconductor market, the machine is said to be equally at home with traditional carbon steel and aluminium applications.
The new machines are said to make use of Apperley’s contour honing process, which employs conformable honing stones to adapt to the oval internal diameters of the tubes to be honed, allowing for a high level of precision polishing without compromising the wall thickness of the tube.
Sanders is upbeat about further developments in honing.
‘Having developed the twin-spindle we’re now looking at triple or quadruple spindle machines as long as the appropriate quality thresholds are achievable.’