Fret saw including a cutting wire provided with fixed abrasive grains each including a core coated with a hard film

1. A fret saw including:

a cutting wire; and

fixed abrasive grains provided on the cutting wire by electroplating and each made with a core and a hard film coated on the core,

wherein the core is 1 to 60 micrometers in diameter and made of a material selected from the group consisting of a Ti metal and a Ti alloy,

wherein the hard film is 1 to 40 micrometers thick and covers about 30% to 90% of the surface of the core.

2. The cutting wire according to claim 1 ,

wherein there is TiC formed between the core and the hard film,

wherein the TiC is 0.05 to 0.5 micrometer thick.

3. The cutting wire according to claim 1 ,

wherein the Ti metal is selected from the group consisting of Si, Ta, Mo, W, Cr, V, Cu, Al and Fe.

4. The cutting wire according to claim 1 ,

wherein the Ti alloy is a combination of at least two materials elected from the group consisting of Si, Ta, Mo, W, Cr, V, Cu, Al and Fe.

5. The cutting wire according to claim 1 ,

wherein the core is in a shape selected from the group consisting of a sphere, a pyramid, a tetrahedron, a hexahedron and an octahedron.

6. The cutting wire according to claim 1 ,

wherein the hard film is made of a material selected from the group consisting of diamond, boron nitride and aluminum oxide.

7. The cutting wire according to claim 1 ,

wherein the core includes a rough surface.

8. The cutting wire according to claim 1 ,

wherein the core includes a porous surface.

9. The cutting wire according to claim 1 ,

wherein the cutting wire is made of steel and made with a diameter of 1.6 mm.