Terry D: I first encountered a mass production problem of small holes on steel oil spray bars that were fitted onto car engines and sprayed oil onto cams and followers of valve gear. When drilled, there would be drill breakage devices on the machines to identify the parts and automatically scrap them - maybe 1 /1000? (Typically 16 holes drilled simultaneously in the bars!). When a drill broke, all 16 drill bits were changed, with consequential high cost of manufacture. Also, any burr on the inside of the drilled hole that had not been cleared away would trap organic sludge "stuff" formed in the oil, which eventually would lead to a blob of goo that blocked the hole = another warranty failure.
Of course, there were those that slipped the controls and got on cars... with subsequent warranty failures of short-life of the affected cam/follower.
So I found a supplier who could laser drill the holes. No drill material or swarf to block holes, as the laser simply vaporised the metal to form holes. Scrap went to zero, Warranty was zero, for this blocked hole or inadequate hole from drill breakage. The laser "drilled" a series holes in a circle, partly overlapping, to give the correct oil feed area, after a bit of simple tuning. I think it used a beam about 0.004" diameter?
But I can't afford a laser drill for my garage...
K2
How can they be manufactured ( 0.002") that remains a mystery. (at least to me)
