Tool unit applied to ultrasonic machining

A tool unit applied to ultrasonic machining comprising:

• an amplitude transformer;
• a machining head, having an array structure with micron machining precision, and disposed beneath the amplitude transformer, wherein the machining head comprises a plurality of material layers comprising:
• a substrate with an upper surface and a lower surface located at two opposite sides of the substrate, wherein the material of the substrate is selected from a group consisting of a steel with thermal expansion coefficient in range from 10.70×10−6K−1 to 17.30×10-6K−1, tungsten carbide and a combination thereof;
• a diamond layer, comprising a material selected from a group consisting of a diamond material with thermal expansion coefficient in range from 1.00×10−6K−1 to 2.50×10−6K−1, a polycrystalline diamond, a diamond sinter and a combination thereof;
• and
• a connecting portion, sandwiched between the amplitude transformer and the machining head and forming a flexible interface layer so that the machining head, the amplitude transformer and the connecting portion are rigidly cemented into an integral tool unit;
• and
• wherein the machining head comprises a surface working layer, the surface working layer and the substrate are disposed at two opposite sides of the diamond layer, the material of the substrate is the steel with thermal expansion coefficient in range from 10.70×10−6K−1 to 17.30×10−6K−1;
• the diamond layer comprises a layer of plural electrophoretic deposited diamond particles with thermal expansion coefficient in range from 1.00×10−6K−1 to 2.50×10−6K−1 embedded in an electrophoretic deposited metal bed layer with thermal expansion coefficient in range from 4.80×10−6K−1 to 13.80×10−6K−1;
• and the surface working layer is a non-metal coating with thermal expansion coefficient in range from 1.00×10−6K−1 to 13.50×10−6K−1 and density thereof is greater than that of the electrophoretic deposited diamond layer.