JPH04146015A - Throw-away tip and end mill - Google Patents

Abstract

PURPOSE:To display excellent effect for finish cutting and contribute to improvement of work efficiency by forming right and left blades of one piece of tip into circular cutting blades which exceed 90 deg. in the direction of an axial line from the center of rotation in a throw-away tip of a ball end mill. CONSTITUTION:In a throw-away tip constituting a ball end mill with two pieces of bottom blades per one, the shape of the cutting blades viewed from the top end in the axial line X direction of a tool is set so that a circular arc is formed to exceed 90 deg. in the axial line X direction from the center of rotation of the end mill. Materials in use can be selected from high speed tool steel, super hard steel, cermet, ceramics, etc., in accordance with using conditions of the tool. In this way, as there are the cutting blades forming circular arcs which exceed 90 deg. in the axial line direction viewed from the side surface, the process of work is realized in such a way as catching a material to be cut radially in the end mill from the extreme outer periphery of the tool, and pulling the end mill upward from such position.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an indexable tip formed with an arcuate cutting edge that is replaceably inserted into the end face of an end mill body, and a ball end mill constructed using the same. It is related to.

[Conventional technology]

2. Description of the Related Art A ball end mill is known that is equipped with an indexable tip that is replaceably inserted into the end face of an end mill body and has two axially symmetric left and right blades.

This type of tool is advantageous in that it has less influence on installation accuracy than a tool made of two or more indexable inserts, and it is easier to obtain the shape accuracy of the bottom edge, which is important in ball end mills.

However, as shown in Fig. 2, the indexable insert conventionally used in this type of tool has an outer circumferential cutting edge that rotates in a cylindrical shape around a rotating shaft, and a ball cutting edge has two
The cutting edge was provided in a substantially straight line when viewed from the tip in the axial direction of the tool, similar to those used in tools consisting of more than one indexable insert.

[Problem that the invention seeks to solve]

As a result of the above, the biting of the cutting edge to the workpiece is better than that of a rectangular shape with a convex curve in the direction of tool rotation, such as those found in high-speed tool steel end mills. Possible problems include inferior life and cut surface roughness.

In connection with the above, it has been generally recognized that indexable tools are not suitable for finishing in milling. In addition, with conventional indexable inserts of this type, there is no machining method in which the rigid material is bited into the end mill radially from the outermost periphery of the tool diameter of the arcuate cutting edge, and the end mill is pulled upward from that position. , it was impossible because it did not have a cutting edge to perform that kind of processing. When cutting a cavity or slope with a conventional indexable ball end mill, the depth of cut is made at the top position, three-dimensional cutting is performed, and when the end mill returns to the top position, the next depth of cut is made in the lateral direction when cutting the bottom surface. This is because if a cutting depth is applied to the cutting edge, the entire surface of the peripheral edge will be involved in cutting, which will sometimes impede cutting performance.

[Object of the present invention]

The present invention aims to eliminate the following drawbacks, realize a new machining method and higher precision cutting using an indexable ball end mill, and provide an indexable tip that can be used for finishing cutting. That is.

[Means to solve the problem]

In order to achieve the above object, the present invention provides an indexable insert constituting a ball end mill having two bottom cutting edges. The cutting edge is set so as to form a convex curve toward the end mill, and to form an arc extending more than 90° in the axial direction from the rotation center of the end mill.

The materials used are high-speed tool steel,
Carbide, cermet, ceramics, etc. can be selected, and by coating these materials, the tool life can be expected to be further extended.

Also, if you are concerned about chipping of the cutting edge.

Honing the cutting edge and notching the edge of the cutting edge near the shaft center to improve chip evacuation are also effective.

[Function J] In the present invention, the indexable tip is inserted into the slit of the tip clamp section, the clamp screw is inserted through the tip clamp section and the indexable tip, and the indexable tip is screwed into one side of the tip. This relates to a throw-away tip used in an end mill body that is fixed to two side surfaces of the tip clamp part, and the semicircular arcuate cutting edge ridge is axially
With the formation of a helical groove of 0° to 45°, the indexable tip exhibits a convex curve when viewed from the front.

The present invention, in combination with the above-mentioned end mill main body,
The indexable insert is stably supported in an accurate position, and the convex curve of the cutting edge reduces cutting resistance, extending tool life and improving the roughness of the cut surface. This has the effect of enabling finish cutting with an indexable tool.

Furthermore, since the end mill has a cutting edge that forms an arc of more than 90" in the axial direction from the tip of the nose when viewed from the side, the workpiece can be bited into the end mill from the outermost circumference of the tool diameter, and the end mill can be cut from that position. It has the effect of realizing a processing method in which the material is pulled upward.

Embodiment C] FIG. 11 shows an embodiment of the present invention. Here, a case is shown in which it is used in clockwise rotation. The thickness of the tip will match the size of the slit in the end mill body used.

The present invention is clear when compared with an example of the conventional product shown in FIG. 2, but the semicircular arcuate cutting edge ridge 11 is different from the one shown in FIG. 3. Since the twisted groove of 20° to 45° is formed in the axial direction, it has a convex curve when viewed from the front.

Further, an arc-shaped cutting edge is provided to the right of the Y-axis in FIG. 1(B), that is, from the tip of the nose of the end mill to a direction exceeding 90° in the axial direction when viewed from the side.

〔Effect of the invention〕

As described above, according to the present invention, the biting of the cutting edge into the work material is improved, the cutting resistance is reduced, and the attachment of the indexable insert is achieved by a synergistic effect with the highly accurate end mill body. It also shows excellent cutting effects.

Furthermore, in side cutting, etc., it becomes possible to cut upwardly by making a cut in the radial direction near the bottom surface. In other words, it can contribute to improving work efficiency.

[Brief explanation of drawings]

Figures 1A and 1B show an embodiment of the product of the present invention, with Figure A being a front view and Figure B being a side view. In FIG. 2, A and B show an example of a conventional indexable tip, with A being a front view and B being a side view. FIGS. 3A and 3B show an example of how the product of the present invention is attached to a throwaway body, and FIG. 3A is a front view thereof, and FIG. 3B is a side view thereof. 1... Indexable tip 2... End mill body 11... Cutting edge ridge line 12... Tip installation is 621... Support bin 22 ...Chip clamp part t...Plate thickness

Claims (3)

[Claims] (1) In the throw-away tip that is used together with the end mill body to form a ball end mill, one tip has two blades on the left and right that include the center of rotation, and the two blades on the left and right each rotate 90 degrees in the axial direction from the center of rotation. A throw-away insert for ball end mills that is characterized by a cutting edge that has a circular arc shape that extends over the entire length. (2) The throw-away insert according to claim 1, wherein the cutting edge has a shape of a convex curve in the tool rotation direction when viewed from the tip in the axial direction. (3) An end mill characterized in that the indexable tip according to claim 1 or/and 2 is used.