JPH03239411A - Helical tooth end mill and manufacture thereof - Google Patents

Abstract

PURPOSE:To manufacture a helical tooth end mill composed of continuous high hardness materials, by fixing the bow-shape high hardness tip that the powders of the high hardness material such as a diamond is sintered with its compression so as to wind on the core material of an end mill. CONSTITUTION:A bow-shape high hardness tip 8 is formed in a bow-shape by using a wire electric discharging machine, etc., from the substrate on which a plate like high hardness material layer is laminated, or both of the high hardness material layer and the substrate of the lower layer are about uniform in the thickness and a plane is made, and the bow-shape high hardness tip 8 whose shape is made a bow-shape is mass-produced by a sinter method. The bow-shape high hardness tip 8 is brazed to a core material 9, after the inside being finished so as to just fit to the core material 9 of an end mill 1. A transferal groove like the bow-shape high hardness tip 8 being just fit is formed on the core material 9 and after brazing the edging grinding run along a helical cutting edge is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a long-life twisted-blade end mill having a highly hard cutting edge capable of cutting with high precision and high efficiency, and a method for manufacturing the same.

[Conventional techniques] Among the conventionally used tool materials, diamond and cubic boron nitride (Cubic Baron N
1tride (hereinafter referred to as CBN) has high hardness,
For example, as shown in FIG. 4, a high hardness tip 5 is provided on a part of the helical cutting edge 4 of an end mill 1 to extend the life of the tool. Diamond-based tool materials are used when cutting non-ferrous materials, and CBN-based tool materials are used to prevent tool deterioration due to carbonization when cutting ferrous materials, resulting in high precision. It is well known that highly efficient cutting can be performed.

However, it is extremely difficult to manufacture the entire helical cutting edge 4 of the end mill l using a high hardness material such as diamond or CBN. The tip 5 was embedded and fixed in the core material 3 of the end mill 1, and this was ground on a grinder with synchronized rotation and feed to produce a twisted-blade end mill. In the twisted-edge end mill manufactured in this way, the twisted cutting edge 4 is composed of a high-hardness tip 5 with discontinuous hardness, so cutting using this causes uneven tool wear and deterioration of machining accuracy. There was the problem of inviting.

On the other hand, because it is difficult to make a helical cutting edge from a high-hardness material such as diamond or CBN, as shown in Fig. Straight-edge end mills are also manufactured that are made by joining the core material of 1, but using this type of tool results in intermittent cutting, which causes minute vibrations due to large fluctuations in cutting force, so it is not possible to achieve high precision and high precision. There was a problem that efficient cutting was difficult.

[Problems to be Solved by the Invention] As mentioned above, when cutting is performed using a conventional twisted blade end mill in which small high-hardness chips with discontinuous hardness are embedded in the conventional twisted cutting blade, the twisted cutting blade becomes There was a problem in that the tool wear was uneven in some parts, resulting in deterioration of machining accuracy. Furthermore, in a straight-edge end mill in which a straight-edge, high-hardness tip is bonded, there is a problem in that the cutting is intermittent, causing minute vibrations, making it impossible to perform cutting with high precision and high efficiency.

An object of the present invention is to solve the problems in the above-mentioned prior art and provide a twisted blade end mill having a twisted cutting edge made of a continuous high-hardness material, and a method for manufacturing the same.
The objective is to realize a twisted-blade end mill that can process grooves with high precision and efficiency, and can be expected to have a long tool life.

[Means for Solving the Problems] In order to achieve the above object of the present invention, 1. a twisted blade-like height having an ideal shape having a high hardness material on the twisted surface, as shown in FIG. 3; It is extremely difficult to make hard chips, so diamond or cubic boron nitride (CBN) is used.
A twisted blade-like high-hardness tip made of a material with a thickness of approximately one birch and the shape of a bow is made, and this is bonded and fixed so as to be wrapped around the core material of the end mill, and the twisted cutting edge is It is something that will be completed.

The twisted-blade end mill of the present invention compresses and sinters powder made of a high-hardness material containing diamond or cubic boron nitride into a flat plate-shaped sintered body having a substantially constant thickness. It is obtained by shaping the body into a bow shape to form a high-hardness chip, bonding and fixing the high-hardness chip so as to wrap it around the core material of an end mill, and finishing the twisted cutting blade.

In addition, the twisted-blade end mill of the present invention compresses and sinteres powder made of a high-hardness material containing diamond or cubic boron nitride to form a bow-shaped high-hardness tip with a substantially constant thickness. However, it can also be produced by winding the high-hardness tip around the core material of an end mill, joining and fixing it, and finishing it into a twisted cutting edge.

In the method for manufacturing a twisted-blade end mill of the present invention, as a typical example, a twisted groove for fitting a high-hardness tip is formed in advance in the core material of the end mill, and the high-hardness tip is brazed into the twisted groove. After joining by
A twisted blade end mill can be manufactured by performing a step of finishing the twisted cutting blade.

[Function] Since the shape of the high-hardness tip used in the twisted-blade end mill of the present invention is a bow-like shape with a substantially constant thickness, it is extremely easy to form a high-hardness tip made of a high-hardness material such as diamond or CBN. becomes.

Therefore, it becomes easy to manufacture a twisted-blade end mill using the above-mentioned high-hardness tip, and it is possible to achieve high precision and even more efficient cutting.

[Example 1] An example of the present invention will be described below in more detail based on the drawings.

11th i! ! I is an external view showing the structure of a twisted-blade end mill with a high-hardness cutting edge according to the present invention. In FIG.
The core material 9 is formed in advance with a groove with a transfer shape into which the bow's shaft-shaped high-hardness tip 8 fits perfectly, just like inserting a denture. A hardness tip 8 is fitted and brazed, and then the blades along the twisted cutting edge are ground and finished.

As shown in FIG.
Then, it is shaped into a bow shape using a wire saw or a wire electrical discharge machining machine (WEDM).

When a large number of end mills of the same size and shape are required, instead of shaping with a wire saw or wire electric discharge machine as described above, the high hardness material layer 11 and the substrate material 10 of the lower layer can be formed together. The thickness is almost one layer and it is flat.
It is sufficient to mass-produce a bow-shaped high hardness tip 8 having a bow-shaped shape by a sintering method.

These high-hardness tips 8 shaped like bow seeds fit perfectly into the core material 9 of the end mill 1.

After finishing the inside of the seed-shaped high-hardness tip 8 of the bow.

Braze to the core material 9.

After that, the bow shaft-shaped high-hardness tip 8 integrated into the end mill 1 is used to correct the errors at the time of cutting and brazing, and to obtain a highly accurate helical cutting edge. is ground, and a twisted-blade end mill 1 having the desired dimensions and shape is obtained.

Here, when machining the fitting part of the bow of the core material 9 with the seed-shaped high-hardness tip 8, the conventional method of applying feed in synchronization with the rotation of the end mill requires a long distance in machining. As is clear from looking at the bow-like axial high-hardness tip 8 from the right side in FIG. 2, attention was paid to the fact that the shape of the high-hardness tip is linear.

The fitting portion of the core material 9 may be machined by feeding the tool in a straight line at an angle of inclination δ of the cutting edge with respect to the axis C of the end mill 1.

Further, in this case, unlike conventional twisted-blade end mill tools, the lead angle is not constant regardless of the position, but varies depending on the axial position of the end mill 1.

Assuming that the lead L advances by the height of the arch-shaped high-hardness tip 8, the nominal lead L is expressed by the following equation.

θ where θ: central angle of the tool cutting edge on a projection plane perpendicular to the tool axis l: length of the cutting edge δ: inclination of the cutting edge.

[Effects of the Invention] As explained in detail above, according to the present invention, a continuous process using an H-shaped high-hardness tip made of polycrystalline sintered material such as diamond or cubic boron nitride* (CBN) is possible. It is now possible to manufacture end mills with twisted cutting edges, allowing highly efficient machining of high-precision grooves in various metal materials.

[Brief explanation of drawings]

FIG. 1 is a three-dimensional diagram showing the structure of the twisted-blade end mill exemplified in the embodiment of this explanation, FIG. FIG. 3 is a three-dimensional diagram showing the ideal shape of a high-hardness tip, FIG. 4 is a three-dimensional diagram showing the structure of a conventional twisted-blade end mill, and FIG. 5 is a three-dimensional diagram showing the structure of a conventional straight-blade end mill. 1... End mill, 2... Shank, 3...
・Core material, 4... Twisted cutting blade. 5... High hardness tip, 6... Straight-edged high hardness tip, 7... Lusou-shaped high hardness tip, 8... 41-shaped high hardness tip with bow, 9... Core material, 10... Substrate material, 11... High hardness material layer.

Claims (1)

[Claims] 1. A powder made of a high hardness material containing diamond or cubic boron nitride is compressed and sintered into a flat plate-shaped sintered body having a substantially constant thickness; Twisting characterized by forming a high-hardness chip by shaping the body into a bow shape, and bonding and fixing the high-hardness chip so as to wrap it around the core material of an end mill to form a twisted cutting edge. Blade end mill. 2. Compress and sinter powder made of a high-hardness material containing diamond or cubic boron nitride to form a bow-shaped high-hardness chip with an approximately constant thickness, and insert the high-hardness chip into an end mill. A twisted blade end mill characterized by a twisted cutting blade formed by being bonded and fixed so as to be wrapped around a core material. 3. In the method for manufacturing a twisted-blade end mill as set forth in claim 1 or 2, a twisted groove is formed in advance in the core material of the end mill to fit a high-hardness tip, and the high-hardness tip is inserted into the twisted groove. A method for manufacturing a twisted-blade end mill, comprising the step of joining the two by brazing and then finishing the twisted cutting blade.