JPS60127912A - Rotary cutting tool of small diameter - Google Patents

Abstract

PURPOSE:To enable a compact tool in small diameter to be manufactured, by inserting a thin plate, formed by longitudinally cutting a compact blank made of diamond or CBN, to be brazed into a split provided in a shank and forming an edge on the thin plate protruded from the shank. CONSTITUTION:A shank 21 made of cemented carbide alloy forms its diameter a little smaller than the nominal size of a drill, providing in the end part of the shank 21 a split 22 into which a compact thin plate 23 is inserted. The thin plate 23, equalizing its lateral width to the nominal size of the drill, forms two surface 25, 26, having a slope defined by a point angle alpha and a clearance angle beta of the drill, in a sintered diamond part 24 in the point end of the thin plate and forms an edge point of the drill with a ridgeline 27, formed by said two surfaces, as a chisel edge. While a sintered alloy part 28 is deeply sunk to be brazed in a groove 22 of the shank 21. Further a base part 29 of the shank 21 is formed in a large size so as to be suitably held. In this way, a compact tool in small diameter, conventionally unable to be manufactured, in the nominal size of 3mm. or less can be presented.

Description

[Detailed Description of the Invention] Diamond compact or OBN compact (hereinafter collectively referred to simply as compact), which is made by sintering fine powder of diamond or OBN (cubic nitride), is used as a material for tools, especially cutting tools. Awarded. Compared to carbide tools, they cut better and generate less heat, so there is no risk of deterioration of the material to be cut, and burrs are less likely to occur. Because built-up edges are rarely created, the cutting finish has a high surface roughness.

Furthermore, due to high wear resistance, tool life is long, and re-sharpening St.
- Usable time until required is >/l1liTfL(r)
The compact is supplied as a blank 1 with a layer 2 of sintered diamond or OBN and a backing 3 of cemented carbide as shown in FIG. The cemented carbide part 3 reinforces the sintered layer 2 and also allows the compact to be attached to the shank by brazing. This is because compacts are generally used only in the cutting section, which is attached to a steel or cemented carbide shank to form the tool.

Typical blank dimensions are sintered Ill 2 thickness 0.5
Dragon, lining 3 is thicker than this, total thickness of blank is 1
．． 5 to 3 mm, and the diameter is 8 to 1311III. In addition to the circular shape shown in FIG. 1, there are various shapes on the market that are useful for cutting tool blades, such as semicircular shapes, fan shapes, and rectangular shapes.

To make a cutting tool, the sintered part 20 Table 1/] i4 t-+H
Generally, the blank has a double-sided surface, and the blank shape described above takes into consideration the type of use of the blank. This configuration method is also adopted for rotary cutting tools A such as drills, end mills, and reamers. Figure 2 is a cross-sectional view showing an example of a two-flute rotary tool.
1 is compact, and the entire blade part is made up of its surface 4 as a scooping surface. 5 is a shank. It is clear from the figure that this structure can be obtained if the thickness T of the compact is larger than the nominal diameter of the tool, and if T is close to 9AK, the shank part 6 is thin and the cutting resistance can be reduced. The receiving strength is insufficient, and the area 7 for brazing is also insufficient.

For this reason, it is desirable that the thickness T of the compact be less than or equal to the nominal diameter A, and that the thickness D be at least four times T.As mentioned above, the thickness of the thinnest blank is 1.5n.
Dust, as long as this is used in one history, the nominal diameter p will be 6 or more and 7. Although it is possible to make the thickness T more γ1.1 by cutting the cemented carbide part of the part, there is a limit to this, and it is impossible to reduce the nominal diameter to less than 3 mm.

1- In general, the smaller the diameter of a rotary tool, the more likely it will wear out (“
Again, depending on the target workpiece material, even carbide tools can have a very short life. It is precisely for this type of tool that a highly wear-resistant compact tool should be used, and there has been a high demand for small-diameter compact rotary tools with a nominal diameter of 3n or less.

The present invention meets this demand by creating a small diameter connosed tool with a nominal diameter of 3 mm or less, which was previously impossible to produce. This is what we provide.

The reason why it was not possible to produce compacts like Higa's is that the thickness T of compacts like Higa's is large, and this restriction cannot be avoided as long as the surface of a commercially available blank is used as the scooping surface. Generally speaking, the scooping surface has a large area among the treads that form the cutting edge of a tool. - million sintered diamond (or OBN)
) becomes more difficult as the area increases, so in order to minimize the polishing process, it is best to use the surface of the blank as the scooping surface, and the shape of the commercially available blank σ] mentioned above is based on this.

However, in a small-diameter rotary tool, the cutting edge is extremely small, and the scooping surface, which is the biggest factor, is also very small, so polishing sintered diamond (or OBN) is not difficult. Therefore, there is no need to use the surface of the blank as a scooping surface, and material can be taken freely. In the present invention, first, a blank is cut as shown in FIG. 1 8 and 8' to obtain the thin plate shown in FIG. 3.

There is no difficulty in cutting if wire-radiation F''lL machining or the like is used.

Thickness 0.2 III! It is easy to make a thin plate of about 100 ml, and it is also possible to make it even thinner by roughly polishing the cut surface. Sintered diamond (or OB
This is because the width U of the portion 12 (N) is only 0.5 mm, so there is no difficulty in polishing the cut surface. Since the upper surface 14 has a smaller area, it is easy to polish and there is no difficulty in machining it into the shape of a blade. The cemented carbide section 13 is brazed to the shank and has a sufficient area to hold the blade. This will be explained in detail below using examples.

Is Fig. 4 an embodiment of the present invention? 2 in the diagram with the small diameter drill shown.
Reference numeral 1 denotes a shank made of cemented carbide, the diameter of which is slightly smaller than the nominal diameter of the drill, and 22 slots are provided from the tip into which a compact thin plate 23 is inserted. 11. v The width of the temporary hole is equal to the nominal diameter of the drill, and the tip of the sintered diamond (or OBN) 424 has an inclination defined by the drill tip angle α and clearance angle β. Take it out and make the ridge angle 27fJ-Chisel Ella, Nshifumk” II
Get the first phantom kill. Compact cemented carbide 1'128
is deeply recessed into the groove 22 of the shank and is brazed. The base 29 of the shank is thickened to suit gripping.

Figures 5 to 7 are examples of a small-diameter end mill in which a slotted 32vc compact thin plate 33 of a cemented carbide shank 31 is inserted.

However, the slot 32 is eccentric to the shank 31 so that its -1000 wall passes through the axis of the shank. The base is thick and the tip 35 has the above-mentioned slot 32 on the shank 31 whose diameter is slightly smaller than the nominal diameter of the end mill.
Cut it to make surface 3g, 40. Compact thin plate 33
is the sintered diamond part 41, the side surface 39 of the shank,
40, and polish a side flank surface 42 with a clearance angle δ. The edge angle 44 between the thin plates 330 and 43 and the side surface 42 forms a complete cross-cutting blade. Note that 11111 and 42 can also be processed into two stages to provide a second flank. The upper end 45 of the thin plate 33 is defined by the sub-cutting angle r and the front relief angle ε. JF) Polish the surface. Alternatively, the tip surfaces of the shank may also be made to have the same inclination and be polished to the same surface as the tip 45 of the compact thin plate 33.

In the above two embodiments, a small diameter drill or one
Equipped with all the features required of a Hirakata end mill, the sintered diamond (or OBN) cutting blade provides excellent cutting action. In addition, during production, it is relatively easy to create the shape of the blade and polish the blade. This feature is due to the use of the compact thin plate shown in Fig. 3 as a secondary material, and this is the basic purpose of the present invention, and it is not applicable to various small-diameter rotary cutting tools other than the two examples listed above. Needless to say.

By fully dividing the shank Kj, inserting the compact thin plate, and brazing the cemented carbide part, the blade part is firmly supported and a well-balanced and stable rotating single-cutting tool is formed. When assembling, the position of the compact thin plate is determined by inserting it into the slot, so brazing is easier than installing it in the conventional configuration, where it is placed at a predetermined position on the entire shank of the chip. It is. The compact thin plate may be attached to the shank after forming and attaching the blade, or the compact plate may be polished to complete the blade after being attached to the shank.

The rotary tool of the present invention is suitable for small diameter tools with a nominal diameter of 3 blades or less,
This made possible a field that was impossible despite high demand from the elderly. A small-diameter rotary tool with a nominal diameter of 1 mmq is easily manufactured, and if micromachining capabilities permit, a rotary tool with a diameter smaller than 1 mm is also possible.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the Diamond Compact, Figure 2 is 2
A cross-sectional view shown at -LfIlJ' of a single-blade rotary cutting tool,
Figure 3 is a perspective view of the thin plate cut by the compactor in Figure 1;
FIG. 4 is a perspective view showing an embodiment of a small-diameter rotary cutting tool according to the present invention, FIG. 5 is a perspective view showing an embodiment of a pond, FIG. 6 is a thousand-sided view, and FIG. This is a perspective view. 21.31~Shayank, 22.32~Suriwari, O, 3
3 ~ Compact thin plate Fig. 1, 4 Fig. 3 Fig. 4 Fig. 4

Claims (1)

[Claims] A small-diameter rotary cutting tool in which a plate obtained by vertically slicing a diamond compact or OBN compact blank is inserted into a slot provided in the shank and fixed by brazing, and a blade is formed on the thin plate protruding from the shank.