KR100574798B1 - Ballnose Endmill for Roughing - Google Patents

Abstract

The present invention relates to a ball nose end mill for roughing, and improves the structure of the cutting insert and the main body to more firmly and easily fix the cutting insert to the main body, thereby increasing cutting force and reducing wear and cracking of the cutting insert and the main body. It is for.

To this end, the present invention is a screw hole formed in the center; An inclined surface that is inclined downward at an angle toward one edge of the circumferential portion of the upper or lower surface; A cutting edge formed by the intersection of the inclined surface and the side clearance surface; A chip former formed at the front end of the inclined surface; A first mounting surface vertically downwardly formed from an upper surface on an opposite side of the side clearance surface; A second mounting surface formed at a constant inclination downward from an upper surface at a rear side of the side free surface; A cutting insert comprising: a pocket inserting portion formed at an angle of α including the first mounting surface, the second mounting surface, and the lower surface thereof;

A seating plane on which the cutting insert is seated; An undercut formed inside the seating plane and accommodating the pocket inserting portion; A mounting inner wall perpendicular to the seating plane; It provides a rough ball-nose end mill, characterized in that consisting of a main body including: a pocket formed with a curved chip guide wall for guiding the chip to the top of the mounting inner wall.

Cutting inserts, chip formers, cutting surfaces, pockets

Description

Ballnose Endmill for Roughing

1 is an exploded perspective view showing a ball nose end mill according to a conventional embodiment

Figure 2 is an exploded perspective view showing a ball nose end mill according to another conventional embodiment

Figure 3 is a perspective view of the roughing ball nose end mill according to an embodiment of the present invention

Figure 4 is a plan view of a rough ball nose end mill according to an embodiment of the present invention

5 is an exploded perspective view of a roughing ball nose end mill according to an embodiment of the present invention;

Figure 6 is a perspective view of the cutting insert of the roughing ball nose end mill according to an embodiment of the present invention

7 is a perspective view of the cutting insert of FIG. 6 viewed from another side;

FIG. 8 is a cross-sectional view of the pocket A to which the cutting insert is mounted as the cross section A of FIG.

FIG. 9 is a cross-sectional view B of FIG. 5 showing an angular relationship between a side cross section of the cutting insert and a screw;

FIG. 10 is a cross-sectional view of the main body chip former for smooth chip flow as shown in FIG.

[Detailed Description of Symbols for Main Parts of Drawings]

101. Body 101a. Undercut

101b. Seating plane 101c. Mounting inner wall

101d. Chip guide wall

102. Insert 102a. Top

102b. Cutting edge 102c. Side margin

102d. First mounting surface 102e. Chip former

102f. Slope 102g. Screw hole

102h. Second mounting surface 102i. Insertion angle

The present invention relates to a roughing ball nose end mill used in mold processing, and more particularly, to improve the cutting insert and the structure of the main body to more firmly and easily fix the cutting insert to the main body to increase the cutting force and cutting To reduce wear and cracks on the insert and body.

In general, end mills are widely used in milling and machining centers, and the demand for end mill machining precision is becoming more and more stringent with the high precision and high performance of equipment.

Ballnose end mills using cutting inserts consist of a steel body and a cutting insert made of cemented carbide and the cemented carbide cutting insert is designed to be firmly coupled to the body by screws.

The end mill is provided with one or more pockets on the outer circumferential surface of the main body, a carbide cutting insert that can be replaced with the pocket, and grooves formed at the rear of each pocket are spaces where chips can be discharged.

The cutting inserts mounted on the pockets each include a top inclined surface, a side margin surface, and a cutting surface formed by the intersection of the inclined surface and the clearance surface and are fixed to the pocket of the pocket by a fixing screw.

Hereinafter, a ball nose end mill for roughing according to one embodiment or another embodiment will be described in more detail.

1 is an exploded perspective view showing an embodiment of a conventional type ball nose end mill, the shaft generated when the cutting insert 12 is mounted in the pocket portion 1a of the main body 1 in the above-described configuration. It is a structure for maintaining the cutting insert 12 in a fixed position by bearing the directional cutting component force, and forming a seating surface bottom projection 1b at the bottom of the pocket portion 1a of the main body 1 and cutting cutting ( The lower end of the 12) is provided with a mounting groove (2a) corresponding to the mounting surface bottom projection (1b).

However, the ball nose end mill of this structure takes an additional step to form the bottom projection 1b on the bottom surface of the pocket portion 1a of the main body 1, and the cutting insert 12 also cuts the seating groove 2a at the bottom. The additional grinding process is required for precise machining, which not only increases the manufacturing cost but also the cutting vibration or the cutting force in the state where the two combinations, i.e., the protrusion 1b and the concave groove 2a, are combined. There is a disadvantage of increased fatigue and breakage because of concentration.

FIG. 2 is an exploded perspective view showing another embodiment of a conventional ball nose end mill, in which the shaft generated when the cutting insert 12 is mounted on the pocket portion 1a of the main body 1 and cut. In order to bear the directional cutting component, the side mounting surface and the side free surface of the cutting insert 12 directly contact the main body, and the seating side wall 11b of the main body 11 is formed into a rounded inward curved surface and is cut therein. The side clearance face 12a of the insert 12 is the structure which abuts.

However, since the side wall of the main body pocket portion 11a that is in contact with the side free surface 12a of the cutting insert 11 is also a curved surface, the machining is difficult and the position of the contact points is different even if there is some error in each surface. There is a problem with the precision of the tool.

The roughing ball nose end mill of the conventional structure exemplified above can accurately match the side free surface 12a of the cutting insert with the seating surface of the main body pocket by machining due to the manufacturing tolerances of the cutting insert 12 and the pocket. Since it is very difficult, it is difficult to obtain roundness of the machining surface after cutting with such a tool, and mounting is unstable, which causes vibration, loosening of screws, and the like during cutting.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and improves the cutting insert and the structure of the main body to more firmly and easily fix the cutting insert to the main body, thereby increasing the cutting force and the wear of the cutting insert and the main body. The object is to provide a rough ballnose end mill that reduces cracking.

The present invention for achieving the above object is a screw hole formed in the center; An inclined surface that is inclined downward at an angle toward one edge of the circumferential portion of the upper or lower surface; A cutting edge formed by the intersection of the inclined surface and the side clearance surface; A chip former formed at the front end of the inclined surface; A first mounting surface vertically downwardly formed from an upper surface on an opposite side of the side clearance surface; A second mounting surface formed at a constant inclination downward from an upper surface at a rear side of the side free surface; A cutting insert comprising: a pocket inserting portion formed at an angle of α including the first mounting surface, the second mounting surface, and the lower surface thereof;

A seating plane on which the cutting insert is seated; An undercut formed inside the seating plane and accommodating the pocket inserting portion; A mounting inner wall perpendicular to the seating plane; It provides a rough ball-nose end mill, characterized in that consisting of a main body including: a pocket formed with a curved chip guide wall for guiding the chip to the top of the mounting inner wall.

Hereinafter, the present invention will be described in more detail with reference to FIGS. 3 to 10.

3 is a perspective view of a roughing ball nose end mill according to an embodiment of the present invention, the pocket is formed on the outer peripheral surface of the end portion of the main body 101, the cutting insert 102 replaceable to the pocket is mounted, The groove 104 is formed so that the chip discharged to the front surface of the cutting insert 102 is pulled out backward.

In the drawing, the cutting insert 102 is inserted into the pocket of the main body and the screw 103 is fixed, wherein the insertion angle α of the pocket insert 102i of the cutting insert 102 is greater than 40 ° and equal to 90 °. Or a smaller range, the angle corresponding to the receiving angle of the undercut 101a into which the cutting insert 102 is inserted, that is, the insertion angle α of the cutting insert insert 102i, is also approximately the insertion of the cutting insert pocket insert. The angle 102i has a range of α.

FIG. 4 is a plan view of a state where clamping is completed in a position where the cutting insert is mounted on the main body, and shows cut portions of cross sections shown in the following figures. FIG.

5 is an exploded perspective view of a roughing ball nose end mill according to an embodiment of the present invention, the main body 101 shown in the drawing is a seating plane 101b on which the cutting insert 102 is seated, and the seating plane 101b. The inner cut 101a formed inwardly to accommodate the pocket insert 102i of the cutting insert and the mounting inner wall 101c perpendicular to the seating plane 101b, and guide the chip to the upper end of the mounting inner wall 101c. And a pocket formed with a curved chip guide wall 101d.

6 and 7 are perspective views showing the front and rear of the cutting insert 102 according to an embodiment of the present invention, the cutting insert 102 is a screw hole (102g) formed in the center and the top or bottom An inclined surface 102f formed at an angle toward the edge of the circumferential portion downward, and a cutting edge 102b formed by the intersection of the inclined surface 102f and the side free surface 102c, and the inclined surface 102f. The chip former 102e formed at the front end portion, the first mounting surface 102d vertically formed downward from the upper surface on the opposite side of the side free surface 102c, and the predetermined slope downward from the upper surface on the rear side of the side free surface 102c. And a pocket inserting portion 102i formed at an internal angle of α including the formed second mounting surface 102h, the first mounting surface 102d, the second mounting surface 102h, and the lower surface.

8 is a cross-sectional view showing the shape and angle relationship of the pocket to which the cutting insert is mounted, wherein the clamping angle γ of the undercut 101a of the main body pocket is smaller than the clearance angle β of the cutting insert second mounting surface 102h, but is larger than β-1 °. It has a large angular range.

9 is a cross-sectional view showing the angular relationship between the side end surface of the cutting insert and the locking screw 13, wherein the screw mounting angle δ is larger than the side clearance angle ε of the cutting insert insertion portion 101i and smaller than 90 °. It has a range.

10 is a cross-sectional view showing the shape of the main body 101 and the shape of the chip former 102e of the cutting insert 102 to facilitate the flow of the chip, and the curved chip former 102e inducing the flow of the processed chip. ) Is in the form of a curved surface suitable for the inclined surface 102f of the cutting insert 102.

Referring to these drawings, in order to more stably mount the cutting insert 102 for roughing, the cutting insert 102 has an angle of the cutting insert upper surface mounting angle α of FIG. 3, and the angle α is a cutting insert ( To facilitate the desorption of 102), it is in the range greater than 40 ° and less than 90 °.

In addition, one side of the clamping part of the cutting insert 102 has an angle range greater than or equal to 45 ° and smaller than 90 ° as shown in FIG. 8, and the second mounting surface 102h has an undercut 101a. In contact with the surface with each γ formed on one side of the strong clamping is possible.

Γ is in an angular range smaller than β but larger than β−1 °.

As shown in FIG. 9, the cross section B of the cutting insert generally has a parallelogram shape, and the mounting angle δ of the screw is greater than the side clearance angle ε of the cutting insert pocket insert 102i to be clamped and is smaller than 90 °. In the screw insert 102g, it is possible to reduce the minimum depth t of the screw head seating portion of the screw hole 102g formed in the cutting insert 102 so that the head of the screw is not exposed to the upper portion of the screw hole 102g. This is to maintain the strength of the cutting insert itself by minimizing the hole processing area.

In FIG. 10, the chip former 102e (chip former) formed at one side of the inclined surface of the cutting insert generates a shape of the chip generated during plunge or drilling, and guides the flow of the chip by guiding the flow of the chip. It is formed to reduce the wear of the body by.

Roughing ball nose end mill that satisfies the above structure can not only clamp the high cutting resistance generated during cutting with a single clamp screw but also maintain a very stable clamping state, thereby preventing cutting vibration. Not only can the tool life be increased, but it is easy to manufacture, it can be expected to reduce the manufacturing cost of roughing ball nose end mill.

Therefore, the cutting insert according to the present invention has the stability of mounting and the convenience of manufacturing the cutting insert pocket, making it easy to manufacture a ball nose end mill, preventing vibration due to prolonging the life of the cutting insert and stable mounting, increasing durability of the main body, and the like. Has the effect of.

In addition, the milling ball nose end mill according to the present invention can be precisely set so that the degree of runout is predominant when the cutting insert is set, and the machining precision and surface roughness of the workpiece are improved during cutting, and the clamping speed is high. High feed and high depth of cut can be used to reduce the working time.

In addition, the life of the cutting insert is improved and stable cutting is more effective when applied to an unmanned machining or automation system.

Since it is possible to manufacture the pickling that is actually performed in the cutting process, it is possible to provide a user with a cheap and high-quality product through the reduction of the manufacturing cost, thereby improving the user's cost and productivity.

Claims (4)

A screw hole formed in the center portion; An inclined surface that is inclined downward at an angle toward one edge of the circumferential portion of the upper or lower surface; A cutting edge formed by the intersection of the inclined surface and the side clearance surface; A chip former formed at the front end of the inclined surface; A first mounting surface vertically downwardly formed from an upper surface on an opposite side of the side clearance surface; A second mounting surface formed at a constant inclination downward from an upper surface at a rear side of the side free surface; A cutting insert comprising: a pocket inserting portion formed at an angle of α including the first mounting surface, the second mounting surface, and the lower surface thereof; A seating plane on which the cutting insert is seated; An undercut formed inside the seating plane and accommodating the pocket inserting portion; A mounting inner wall perpendicular to the seating plane; The ball nose end mill for roughing, characterized in that consisting of a main body including: a pocket formed with a curved chip guide wall for guiding the chip to the top of the mounting inner wall. The method of claim 1, Ball-nose end mill for roughing, characterized in that the insertion angle of the pocket insert portion α of the cutting insert is greater than 40 ° and equal to or less than 90 °. The method of claim 1, Clamping angle γ of the main body pocket is in the angular range of less than the cutting insert mounting surface clearance angle β but larger than β-1 °. The method of claim 1, The mounting angle δ of the screw roughing ball nose end mill, characterized in that in the angular range larger than the side marginal angle ε of the insert of the cutting insert less than 90 °.

Images