Welsh scientists drill world's smallest hole

Researchers at Cardiff University's Manufacturing Engineering Centre have managed to drill holes in steel as small as 22 microns (0.022 mm) in diameter using a electro-discharge machining (EDM) process, and reckon they could be the smallest ever achieved.

EDM is also known as "spark machining" and basically involves machining conductive materials using sparks discharged from an electrode. According to Space Daily, the Cardiff Uni EDM process uses a six micron diameter electrode created using the agreeably-named "wire electrode discharge grinder". The centre's marketing supremo, Frank Marsh, explained: "The holes we are now drilling in Cardiff with the electro-discharge machining process could be the smallest in the world.

"The standard rods available commercially are capable of making holes of 150 microns. Although lasers are able to make small holes, these are of poorer quality when compared to the EDM process. Lasers make holes that taper, whereas EDM makes parallel or vertical holes."

Marsh admitted that the Japanese claimed as far back as 1985 to have created a five-micron rod using a grinder similiar in principle to the Welsh machine, but no further evidence has emerged.

The ability to drill very, very small holes will, the researchers say, be of immense benefit in the production of optical and medical eqipment, as well as in the manufacture of electronic components. ®