Waterjet method cuts complex shapes in very hard materials

The subtractive manufacturing technique is particularly useful for very hard materials such as ceramics and is being used for aerospace applications and medical prosthetics.

While waterjets have been used for decades to slice clean through sheet materials, the ability to mill shapes with jets is relatively new.

The key to enabling this is the ability to control the depth of penetration of the jet into the part being milled.

‘It depends how much time we’re exposing the part to the jet — so we’re moving with different speeds,’ project lead Prof Dragos Axinte of Nottingham University explained.

‘We developed some models and we know how the part will erode at particular feed speeds; that’s the key element behind the work we are doing.’

The team uses water laced with abrasive garnet particles, which is forced out under pressure as a jet 1mm in diameter travelling at around two to three times the speed of sound.