A tool unit applied to ultrasonic machining, includes an amplitude transformer, a machining head and a connecting portion. The machining head has a micron-sized array structure. With the connecting portion, the amplitude transformer and the machining head are assembled together and the connecting portion has a change in shape. The machining head includes a substrate and at least one diamond layer. An upper surface of substrate touches the amplitude transformer or the connecting portion. And the diamond layer is disposed on an lower surface of substrate. The material of the substrate is selected from a group of a steel material with thermal expansion coefficient ranged from 10.70×10.sup.−6K.sup.−1 to 17.30×10.sup.−6K.sup.−1, tungsten carbide and combination thereof. The material of the diamond layer is selected from a group of a diamond material with thermal expansion coefficient ranged from 1.00×10.sup.−6K.sup.−1 to 2.50×10.sup.−6K.sup.−1, a polycrystalline diamond, a diamond sintered body and combination thereof.

A tool unit applied to ultrasonic machining, includes an amplitude transformer, a machining head and a connecting portion. The machining head has a micron-sized array structure. With the connecting portion, the amplitude transformer and the machining head are assembled together and the connecting portion has a change in shape. The machining head includes a substrate and at least one diamond layer. An upper surface of substrate touches the amplitude transformer or the connecting portion. And the diamond layer is disposed on an lower surface of substrate. The material of the substrate is selected from a group of a steel material with thermal expansion coefficient ranged from 10.70×10.sup.−6K.sup.−1 to 17.30×10.sup.−6K.sup.−1, tungsten carbide and combination thereof. The material of the diamond layer is selected from a group of a diamond material with thermal expansion coefficient ranged from 1.00×10.sup.−6K.sup.−1 to 2.50×10.sup.−6K.sup.−1, a polycrystalline diamond, a diamond sintered body and combination thereof.

An ultrasonic resonator support structure 10 including a holder 17 supports an ultrasonic resonator 16 at both sides such that the ultrasonic resonator 16 is rotatable to the holder 17. The ultrasonic resonator 16 includes an ultrasonic horn 13 with a machining tool 12 attached, and a first booster 14 and a second booster 15 coaxially fixed one by one to both ends in the axial directions of the ultrasonic horn 13. The holder 17 has a rolling bearing mechanism 18 that rotatably supports the first booster 14 side of the ultrasonic resonator 16 and a gas bearing mechanism 19 that rotatably supports the second booster 15 side of the ultrasonic resonator 16.

An ultrasonic resonator support structure 10 including a holder 17 supports an ultrasonic resonator 16 at both sides such that the ultrasonic resonator 16 is rotatable to the holder 17. The ultrasonic resonator 16 includes an ultrasonic horn 13 with a machining tool 12 attached, and a first booster 14 and a second booster 15 coaxially fixed one by one to both ends in the axial directions of the ultrasonic horn 13. The holder 17 has a rolling bearing mechanism 18 that rotatably supports the first booster 14 side of the ultrasonic resonator 16 and a gas bearing mechanism 19 that rotatably supports the second booster 15 side of the ultrasonic resonator 16.

A surface treatment method for metal parts includes a polishing step of supplying and discharging a cleaning liquid into and from a barrel tub while mass including a metal part and a medium is caused to flow in the barrel tub, so that a surface of the metal part is polished. The polishing step is carried out at least once. The polishing step includes a final finish polishing process in which a final finish medium which is free from abrasive grain or which consists of a synthetic resin base material and is free from abrasive grain or which is made by binding abrasive grain of not more than 10 wt % and a synthetic resin binding material together and is free from alumina is used as the medium.

A surface treatment method for metal parts includes a polishing step of supplying and discharging a cleaning liquid into and from a barrel tub while mass including a metal part and a medium is caused to flow in the barrel tub, so that a surface of the metal part is polished. The polishing step is carried out at least once. The polishing step includes a final finish polishing process in which a final finish medium which is free from abrasive grain or which consists of a synthetic resin base material and is free from abrasive grain or which is made by binding abrasive grain of not more than 10 wt % and a synthetic resin binding material together and is free from alumina is used as the medium.

A method of treatment of a cutting piece (2) is provided. This method includes a first step in which a cutting surface (5) of this cutting piece (2) is subjected to shots thrown by an ultrasonic shot peening apparatus (10) to become a cutting surface (5) with shot impacts, and a second step in which the cutting surface (5) with shot impacts is grinded over a chosen thickness to become a treated cutting surface (5).

A method of treatment of a cutting piece (2) is provided. This method includes a first step in which a cutting surface (5) of this cutting piece (2) is subjected to shots thrown by an ultrasonic shot peening apparatus (10) to become a cutting surface (5) with shot impacts, and a second step in which the cutting surface (5) with shot impacts is grinded over a chosen thickness to become a treated cutting surface (5).

The handpiece-type high-frequency vibration apparatus includes a roughly cylindrical housing 10 configuring a handpiece, a holding member 11, a tool 12, a controller 20 and an excitation device 21. In a non-contact state before the tool 12 is brought into contact with an object, the controller 20 drives the excitation device 21 so as to vibrate the tool 12 at an added frequency fp for which a predetermined frequency fs is added to a first resonance frequency fr1 of the tool 12. In a cutting state where the tool 12 is in contact with the object by a load that enables cutting of the object by the tool 12, the controller 20 controls drive of the excitation device 21 such that a third resonance frequency fr3 of the tool 12 increases and coincides with the added frequency fp, and increases a vibration frequency of the tool 12.

A medical instrument and method for producing a medical instrument with at least one instrument body part made from an instrument body part blank by forming. The at least one instrument body part has at least one deburring face formed by milling. The at least one deburring face includes one or more portions. Each portion extends perpendicularly to a machining plane. A normal to the machining plane defines a deburring longitudinal axis.