JPS59219111A - Endmill - Google Patents

Abstract

PURPOSE:To obtain a sharp cutting action in cutting particularly stainless steel, Ti alloys, or heat resisting steel, while giving a longer life to the endmill, by combining functionally and reasonably a base material of cemented carbide, twisted blades and covering layers. CONSTITUTION:The tool body 1 consists of cemented carbide covered with PVD, and provided with three twisted blades 2. These blades are twisted by 35-60 degrees, and their cutting edges 3 are honed by 0.01-0.05mm.. The covering layer consists of one of more of Ti carbide, nitride and oxide with thickness less than 5mu, and the tool body has a structure of micrograin tungsten carbide.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an end mill, which is particularly suitable for machining stainless steel, Ti alloys, heat-resistant alloys, and the like.

Conventionally, there is no dedicated carbide end mill for end milling of stainless steel, Ti alloys, heat-resistant alloys, etc., and high-speed steel end mills with oxidized tool surfaces are commercially available, but they are not necessarily good. It was something.

Therefore, as demand for stainless steel, Ti alloys, and heat-resistant alloys increases, there is a need to develop end mills suitable for this type of cutting.

The present invention has been made in view of the above-mentioned points, and includes an end dome 7 made of cemented carbide having a coating layer in which a twisted edge is formed in the axial direction of the tool body. The present invention provides an end mill suitable for machining stainless steel and the like by functionally and rationally combining base materials of 1 and cemented carbide.

An embodiment of the end mill of the present invention will be described below with reference to the drawings.

In Figures 1 to 3, (1) is a tool body made of cemented carbide, and on the outer periphery of its tip are three twisted blades (2
) is formed, and on the end face side one of the end face blades (3) forms a central blade leading to the center of rotation.

The cemented carbide forming the tool body (1) is, for example, 1
A cemented carbide with ultrafine WC of 8 m or less is selected. This is because rigid materials such as stainless steel ports have high tensile strength and high cutting resistance during machining, so it is desirable to use cemented carbide with excellent breakage resistance. . This is also due to the cutting speed in the low speed range due to the diameter of the tool tip.

The twisting blade has three blades, and its twisting angle is 35″ to 60″.
It is preferably set within the range of 40° to 50°. Since this falls within the range of strong torsion, firstly, the cutting resistance that the tool receives from the machined wall surface becomes smaller, and this improves the finished surface roughness, improves the precision of the machined shape, and eliminates χ.
This improves the Y-shaped chatter vibration generation limit, and secondly, the impact force when the cutting edge bites into the workpiece material is alleviated. This method was adopted because it has the advantage of being able to reduce the degree of hardening and the thickness of the hardened layer for workpiece materials that have hardenability, as well as raising the limit on the occurrence of chatter vibrations caused by repeated impact. It is something.

On the other hand, the reason why we adopted a three-flute design was to compensate for the decrease in tool strength due to the highly twisted twisted blade, and to
An appropriate angle is within the range of 60°, preferably within the range of 40° to 50°. In other words, due to the strong twist, firstly, if the tool has two flutes, the torsion groove will taper and the tool strength will decrease; secondly, the strength of the cutting edge will also decrease; and thirdly, the strength of the cutting edge will decrease. Disadvantages such as the tendency to occur, the cutting back force increases, and the tool becomes easier to pull out, and fourth, when the cutting width is wide such as in groove machining, chip evacuation is poor and chip clogging is likely to occur. Therefore, these disadvantages were compensated for by making it a three-blade blade.

In addition, the cutting edge of these twisted blades (2) has a thickness of 0.01 to 0.
．． 05mm honing is applied. This is for processing work-hardened layers such as stainless steel. That is, the sharper the cutting edge of an end mill, the less cutting resistance and the better the sharpness, but this is because it is necessary to increase the strength of the cutting edge when processing the work-hardened layer. Considering the balance between the two, the appropriate honing amount is 0.01.
~0.05mm.

For this honing, commonly seen angular or round honing is applied.

The end mill of the present invention has a coating layer formed not only to improve wear resistance but also to prevent damage caused by crimping and separation on the rake face of the tool, which is often seen in stainless steel machining and the like. Since this coating layer is cut intermittently, it is desirable that its thickness be 5 μm or less.

The coating layer is made of Ti carbide, nitride, and oxide.
In other words, T iC+ T iN +T
ie, T1CN, and TiCN0, and a CVD method or a PVD method is appropriately selected as the method. However, the most suitable coating method is a PVD method such as ion blasting or sputtering. This is because there is little decrease in toughness of the cemented carbide base material, and since the processing temperature is low, there is no need to worry about a decrease in tool accuracy.

In this example, the diameter of the cutting edge is 6 mm, and the twist angle θ is 4.
0'', and TiC was selected as the coating layer.

As a result of wet-cutting stainless steel fi (SUS304) using the end mill of the present invention configured as described above, continuous cutting was possible even after cutting 24.4 m. The cutting conditions at this time are cutting speed V = 41.5 m/r
rXi n , feed f = 0.02 rp, m, /tooth, which is approximately 1 hour 30 when converted to cutting time.
It's a minute.

As explained above, the present invention is a functional and rational combination of a cemented carbide base material, a twisted edge, and a coating layer, so it has excellent sharpness especially when cutting stainless steel, Ti alloy, heat-resistant steel, etc. It has the advantage of good performance and long life.

[Brief explanation of drawings]

Figure 1 is a front view showing one embodiment of the end mill of the present invention, Figure 2 is an enlarged view, and Figure 3 is a partial top view of Figure 2. (1)...Tool body (2)・River・
・Twisted blade (3)...End face blade

Claims (2)

[Claims] (1) In the axial direction of the tool body, in an end mill made of cemented carbide having a coating layer in which a twisted edge is formed, the twisted edge has three blades, and the twist angle is 35″~
within the range of 60°, preferably within the range of 40° to 5σ, and the cutting edge is honed to a depth of 0.01 to 0.05 am, and the coating layer has a thickness of 5 μm or less. 47. An end mill comprising: la or two or more of carbides, nitrides, and oxides of Ti, and further characterized in that the tool body is made of a cemented carbide having an ultrafine WC structure. (2) The end mill according to claim 1, wherein the coating layer is coated by PVD.