JPS6144601B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a diamond cutting tool that can finish the machined surface of a workpiece to a mirror finish.

In conventional diamond cutting tools, the rake face of the diamond chip attached to the cutting tool holder is flat, and the tip of the rake face forms a straight cutting edge with a small front clearance angle, so the feeding of the cutting tool can be finely controlled. Even when cutting, feed marks called kerf marks appeared on the cut surface, making it impossible to achieve a highly accurate mirror finish. Furthermore, the machined surface is affected by the polishing state of the tool bit, making it difficult to obtain a mirror surface, and it is also difficult to achieve parallelism of the cutting edge to the machined surface, requiring a long time for setting.

In order to eliminate such conventional drawbacks, the present invention has the following features:
At the tip of the rake face of the cutting edge of the diamond chip,
A burnishing edge formed by a cutting edge with a positive front relief angle and a burnishing surface with a negative front clearance angle is provided adjacently, and the machined surface cut by the cutting edge is effectively cut with the burnishing edge. It has a burnishing finish to easily obtain a mirror surface.

Embodiments of the present invention will be described below based on the drawings.
In FIGS. 1 to 4, reference numeral 10 denotes a diamond chip, which is fixed to the tip of the tool holder 11. This diamond chip 10 has a concave shape with a small straight portion formed at the tip. The upper surface of this diamond chip 10 is
A planar rake face 12 having a positive rake angle is formed, and a cutting edge ridge 15 having a positive front clearance angle and a burnishing ridge 16 having a negative front clearance angle are formed on the straight portion at the tip of this rake face 12. It is formed. In order to form the cutting edge 15 and the burnishing edge 16, the front flank 1 of the tip of the diamond chip 10 is
3 is a first front clearance surface 13-1 and a second front clearance surface 13- which have a positive front clearance angle α and whose intersection with the rake face 12 is bent at a minute angle γ on the rake face. It's more familiar than 2. The intersection line between one first front flank 13-1 and the rake face 12 becomes the cutting edge ridge 15, and this cutting edge 15 has a positive front edge due to the angle formed by the first front flank 13-1. It has a relief angle α. A burnishing surface 17 with a minute width b is formed at the intersection of the other second front relief surface 13-2 and the rake surface 12, and this burnishing surface 17 has a minute negative front relief angle β. There is. The line of intersection between this burnishing surface 17 and the rake surface 12 becomes the burnishing ridge 16, and this burnishing ridge 16 has a negative front relief angle β due to the angle formed by the burnishing surface 17. Therefore, the intersection line 18 between the second front flank 13-2 and the land surface 17 protrudes by a minute amount with respect to the burnishing edge 16, and the machined surface cut by the cutting edge 15 becomes The burnishing edge 16 and the burnishing surface 17 are smoothed and the burnishing finish is effectively performed. Incidentally, side flank surfaces 20, 2 located on both sides of the front flank surface 13
1 has a positive side relief angle, and this side relief surface 20,2
1 and the rake face 12, the cross-cutting edge 2
2 and 23 are formed.

In the diamond tip 10 having the illustrated cutting edge shape, the attachment angle of the diamond tip 10 to the machined surface of the workpiece W is such that the burnishing ridge 16 is almost parallel to the machined surface. The degree is not necessarily necessary, and it is sufficient to have an angle range in which the burnishing edge 16 or the cutting edge edge 15 is parallel to the machined surface, and it is not necessary to set the mounting angle strictly as in the conventional case. Moreover, the feeding direction of the diamond chip 10 is
This is the direction of the cutting edge with respect to the burnishing ridge 16, and in the case of the diamond chip 10 having the illustrated cutting edge shape, feed is given in the direction of arrow A in FIG.

When the cutting edge makes a minute cut into the machined surface and a minute feed is applied in the feeding direction, the workpiece is cut by the cutting edge 15 and the side blade 22 that come into contact with the machined surface of the workpiece. This cutting edge 15 has a positive front relief angle and is also set at an angle γ with respect to the burnishing edge 16, so that the cutting edge 15 has a good cutting quality, and when the workpiece is torn, there are no scratches on the surface. It becomes shallow. Furthermore, even if a crack is generated by tearing the workpiece at the edge portion 24 at one end of the cutting edge 15, this crack is removed by the inclined cutting edge 15, so the amount of burnishing is shallow and it is easy to obtain a good surface. do. This cutting edge 15
Since the burnishing ridge 16 following this has a negative front relief angle, the machined surface is smoothed and the burnishing finish is effectively performed. As a result, a black mirror surface without feed marks can be easily obtained.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a perspective view of the tip of a diamond cutting tool, FIG. 2 is a plan view thereof, FIG. 3 is a front view of the cutting edge, and FIG. 4 is a right side view thereof. It is. 10...Diamond chip, 12...Rake face,
13...Front flank surface, 13-1...First front flank surface, 13
-2...Second front flank, 15...Cutting edge ridge, 16...Burnishing ridge, 17...Burnishing surface.

Claims (1)

[Claims] 1. In a diamond cutting tool for mirror finishing, in which the rake face of the cutting edge of the diamond tip is flat, and the cutting edge is the intersection line of the flat rake face and the front flank face, the front flank face has a positive a first front relief surface and a second front relief surface that have a front relief angle and are angled such that a line of intersection with the rake surface is refracted by a minute angle; both front relief surfaces and the rake surface; A very narrow burnishing surface having a small negative front clearance angle is formed on one of the cutting edge edges formed at the intersection line with A diamond bite.