KR100320127B1 - Milling cutting insert having convex and concave cutting edges - Google Patents

Abstract

By designing the shape of the main cutting part using at least three uneven curvature radii, it minimizes the thermal impact generated during cutting and minimizes the cutting resistance applied to the main cutting part, and configures the inclined surface of the main cutting part in the uneven shape. In addition, there is disclosed a milling cutting insert which not only minimizes the transfer of cutting heat to the tool but also minimizes the frictional resistance between the inclined surface and the discharge chip, thereby improving the wear resistance and the cutting edge strength. The milling cutting insert according to the present invention has at least one major cutout, a subcutaneous part, a bottom part, and a first edge cutout and a second corner cutout, respectively provided at two corners of the upper surface so as to be symmetric in a diagonal direction. . The major cutout extends between the first edge cutout and the second corner cutout to have at least three uneven curvature radii at a boundary position between the top surface and the main cutout side. The inclined surface of the main cutting portion is formed to extend from the main cutting portion to the center of the upper surface while forming the uneven surface.

Description

Milling cutting inserts with concave and cut off {Milling cutting insert having convex and concave cutting edges}

The present invention relates to a cutting tool for cutting a workpiece into a desired shape by mounting it on a rotary milling cutter during milling, and more particularly, by designing the shape of the main cut portion using at least three uneven curvature radius, In addition to minimizing the thermal shocks generated, it also minimizes the cutting resistance applied to the main cutting edges, and by forming the inclined surface of the main cutting edges in an uneven shape, it minimizes the transfer of cutting heat to the tool, The present invention relates to a milling cutting insert which minimizes frictional resistance and improves abrasion resistance and edge strength of a principal cutting edge.

In general, a cutting tool is mainly used for cutting ferrous, nonferrous metals, and nonmetallic materials, and is a tool that is usually mounted on a machine tool to perform cutting to process a workpiece into a desired shape. Typically, such a cutting tool consists of a cutting insert having a cutting edge and a body for holding the cutting insert.

On the other hand, there are two ways to cut the metal using a cutting tool, firstly the cutting is performed by contacting the pickled portion of the cutting tool fixed to the rotating metal workpiece. Secondly, the tool with the cutting edge, i.e. the cutting insert, is fixed to the machine tool using the tool holder, and then the workpiece is processed into the desired shape by contacting the fixed workpiece while rotating the cutting tool under such conditions. It is.

Milling is one of the second methods of the metal cutting method, using a milling cutter to perform a planar, side, square, grooving, hole processing and the like. When the depth of machining is increased in the right angle and side processing, the length of the cutting edge which contributes to the cutting becomes longer and accordingly the resistance that the cutting edge receives as a whole becomes larger. Various efforts have been made to improve tool life in high speed cutting, high feed cutting and high cutting cutting.

For example, WO 94/16847 discloses cutting that reinforces the edge strength according to the change of the cutting depth by changing the inclination angle of the cutting insert edge located at the beginning of the cutting depth and the end of the deepest cutting. Inserts have been disclosed. By the way, the cutting insert reinforces the pickling strength by reducing the inclination angle at the beginning of the pickling and increasing the inclination angle at the pickling end. However, in the concept of cutting, the cutting resistance increases as much as the depth of cut is increased. Because of the catch, better machinability is required. If this is not done, normal processing may not be performed due to the nonuniformity of the cutting resistance received by the pickled portion.

Next, EP 416901 discloses a cutting insert in which the clearance angle of the clearance surface is kept uniform at the cutting edge start and cutting edge end. In this cutting insert, however, the clearance angle is the same at the beginning of the pickling and at the end of the pickling, so that the resistance of the picking start is relatively increased than the picking end. As a result, there was a problem in that the resistance received by the entire cutout portion was inappropriate when the machining was performed with the maximum cutting amount.

If the prior art is analyzed rigorously, the change of the depth of cut may cause unreasonable characteristics, resulting in lower cutting edge strength or increased cutting resistance, resulting in reduced tool life and chipping or breakage. It can be seen that.

The present invention has been made to solve the above-described problems, the object of the present invention is to design the main cutting portion using at least three uneven curvature radius, the axial inclination angle received by the cutting edge in accordance with the change of the cutting amount , By effectively changing the radial inclination angle, and when the infeed is maximized, the effect given by the convex curvature radius of the center part, the concave curvature radius between the center part and the pickling start, and the concave curvature radius between the center part and the pickled end The present invention provides a milling cutting insert which reduces the frictional resistance and improves the strength of the cutting edge by effectively arranging the resistance of the cutting edge at the cutting moment.

It is another object of the present invention to provide a milling cutting insert having a small inductance of the cutting heat contained in the cutting chip and a small frictional resistance between the cutting chip and the inclined surface by forming the inclined surface shape of the major cutting portion into the uneven curved surface. It is.

1 is a perspective view of a milling cutting insert according to a preferred embodiment of the present invention,

FIG. 2 is a view of the milling cutting insert shown in FIG. 1 viewed from the “X” direction; FIG.

3 is a cross-sectional view taken along line III-III of FIG. 2;

4 is a plan view of the milling cutting insert shown in FIG.

5 is a bottom view of the milling cutting insert shown in FIG. 1, FIG.

6 is a cross-sectional view taken along the line A-A of FIG.

7 is a cross-sectional view taken along the line B-B of FIG.

8 is a cross-sectional view taken along the line C-C of FIG. 1, and

9 is a cross-sectional view taken along the line D-D of FIG. 1.

<Explanation of symbols for main parts of drawing>

100: milling cutting insert 101: circular opening

110: upper surface 112: floor

114: Goal 120,122,130: Slope

124: upper face 140: the main cut

141: Land surface of the first week 141a: First surface of the land

142: land surface which is the second main temple 142a: second surface which is the second main temple

143: Land surface of the third week 143a: Third surface of the third temple

144: Land surface of the fourth festival 144a: Fourth temple of the land

145: Land surface which is the fifth festival 145a: Land festival which is the fifth festival

150: main cutting edge side 151: first side compartment

152: second side compartment 153: third side compartment

154: side of the female part 155: side of the lower part

156: first corner side 157: second corner side

160: mosquito 162: moss land

164: subcutaneous 170: first corner pickled

170a: first edge pickled 170b: first edge pickled land surface

172: second corner pickle 172a: second corner pickle

172b: second side pickled land surface 180: low part

182: Land Land 184: Land

In order to achieve the above object, the present invention,

In the milling cutting insert comprising an upper surface, a lower surface, and a circular opening formed through the center, and used for mounting to a milling cutter,

At least one major cutout, a minor cutout, a lower cutout, and a first edge cutout and a second corner cutout, each provided at two corners of the upper surface to be symmetrical in a diagonal direction, wherein the major cutout is in the upper surface; And extending between the first and second corner cutouts to have at least three uneven curvature radii at a boundary position of the side of the main cutout and the inclined surface of the main cutout forming an uneven surface from the main cutout. It provides a milling cutting insert, characterized in that formed to extend toward the center of the upper surface.

The main cutout includes main cutouts and main cutout surfaces having different curvatures, and among the main cutouts, the first main cutout and the fifth main cutout are straight main cutouts, and the second main cutout and the fourth main cutout. Is the concave main temple, and the third is the convex main temple.

In this case, the second main cut and the fourth main cut has a radius of curvature of 10 to 50 mm. The central position of the third main cutout lies between 1/4 to 3/4 of the entire length of the main cutout, and the third main cutout has a radius of curvature of 10 to 60 mm.

The major land surfaces have a width of 0.01 to 0.5 mm and a land angle of -25 to +30 degrees.

The major cutting edge side has a clearance angle of 30 degrees or less with respect to the main cutting edge. The major cut-out side includes a first side section that is a reference side, a second side section that is a side of concave curvature, and a third side section that is faced with a constant slope.

As mentioned above, according to the present invention, the shape of the major cutting edge of the milling cutting insert is designed using at least three uneven curvature radii, and the inclined surface of the major cutting edge is formed into the uneven shape so that the heat generated during cutting is transferred to the tool. Minimizing the transmission and minimizing the cutting force applied to the main cut. In addition, the frictional resistance between the inclined surface and the discharge chip is minimized to greatly improve the wear resistance of the cutting insert and improve the edge strength of the main cutting edge.

Hereinafter, a milling cutting insert according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view of a milling cutting insert according to a preferred embodiment of the present invention.

As shown in FIG. 1, the milling cutting insert 100 according to the present invention is mainly manufactured by using a process such as mold pressure, sintering, grinding, etc. of a cemented carbide material. The milling cutting insert 100 uses only the upper surface 110 in the cutting of ferrous or nonferrous metals. To this end, only the upper surface 110 is provided with a chip breaker (chip breaker).

In the center of the milling cutting insert 100, a circular opening 101 is vertically penetrated, and in the circular opening 101, a boss for fixing the milling cutting insert 100 to a holder for a milling tool (not shown). 102 is installed.

The milling cutting insert 100 has a rotational symmetry of 180 degrees with respect to the center of the circular opening 101. Accordingly, the milling cutting insert 100 has a first edge cutout 170 and a second edge cutout 172 respectively provided at two corners of the upper surface 110 so as to be symmetrical in the diagonal direction.

The first edge pickled portion 170 is composed of a first edge pickled 170a and a first edge pickled land surface 170b, and the second corner pickled portion 172 has a second edge pickled 172a and a second edge. It is comprised by the pickled land surface 172b. The first edge pickle 170a mainly used in milling has a radius of curvature of 0.1 to 7.0 mm, while the second edge pickle 172a used for laying down a tool has a radius of curvature of 0.1 to 3.0 mm. Have

Between the first corner cutout 170 and the second corner cutout 172, a main cutout 140 is formed to extend, and the first corner cutout 170 and another second corner cutout 172 are formed. Between the cut portion 160 and the bottom portion 180 is formed to extend. The chamfer 160 is for improving the surface roughness of the processed workpiece bottom surface, and is composed of a chamfering land surface 162 and chamfer 164. The low phosphorus 180 is composed of a low phosphorus land surface 182 and a low phosphorus 184.

The main cutting portion 140 contributes to cutting while primarily contacting the workpiece during cutting, and is formed at a boundary position between the upper surface 110 and the main cutting edge side 150. The main cutting portion 140 may increase or decrease the number of curvatures according to the length thereof, and typically, the main cutting segments 140 having three to five kinds of curvatures meet each other while forming a natural curved surface.

FIG. 2 is a view of the milling cutting insert shown in FIG. 1 viewed from the “X” direction. FIG.

Referring to FIGS. 1 and 2, the main cutouts 140 may include main cutouts 141a, 142a, 143a, 144a and 145a having different curvatures, and land surfaces 141, 142, 143, 144 and 145 having different curvatures. Among the main temples 141a, 142a, 143a, 144a, and 145a, the first main temple 141a and the fifth main temple 145a are straight main temples, and the second main temples 142a and the fourth main temples 144a. ) Is a concave major cutout having curvature radii Ra and Rb of 10 to 50 mm. The third major cutout 143a is a convex main cutout having a radius of curvature Rc of 10 to 60 mm, preferably 30 to 40 mm. The center position of the third major cutout 143a is between a point that is 1/4 to 3/4 of the entire length of the main cutout 140.

3 is a cross-sectional view taken along line III-III of FIG. 2.

2 and 3, the major cutting edge side 150 has an allowable angle of 0 to 30 degrees with respect to the main cutting edge 140. The major cutout side 150 is composed of a first side compartment 151 that is a reference side, a second side compartment 152 that is a side of concave curvature, and a third side compartment 153. The first side section 151 has a flat surface and is in close contact with the tip seat side portion of the tool holder when the milling cutting insert 100 is fastened to the holder for the milling tool. The second side section 152 is a side of the concave curvature Rm provided to solve the mold fabrication problem caused by the convex curvature Rc shown in FIG. 2, and has a clearance angle greater than that of the first side section 151. small. Since the second side partition 152 is shaped in combination with the convex curvature Rc, it contributes to the improvement of pickling strength during cutting. The third side section 153 is surface-treated at a constant slope to prevent contact with the workpiece during cutting.

4 is a plan view of the milling cutting insert shown in FIG.

Referring to FIG. 4, major cut lands 141, 142, 143, 144, 145 extend from major cut side 150 (see FIGS. 1 and 2). The major land surfaces 141, 142, 143, 144 and 145 have an area of 0.01 to 0.5 mm and a land angle of -25 to +30 degrees. The land surfaces 141, 142, 143, 144, and 145, which are major cuts, are surfaces in which chips generated during cutting of ferrous, non-ferrous metals and non-metals are primarily in contact with each other. It is a surface configured to prevent the damage or defect by reinforcing the strength of.

The top surface 110 of the cutting insert 100 is left ungrind, honed, buffed or mirrored. The upper surface 110 is formed lower than the corner cutouts 170 and 172 and the main cutout 140. The upper surface 110 is formed of a free curved surface to reduce cutting resistance, similar to the land surfaces 141, 142, 143, 144, and 145, which are major cuts. To this end, at least one uneven floor 112 and a valley 114 are formed on the upper surface 110. The ridges 112 and valleys 114 extend symmetrically about the centerline L to land surfaces that are opposite major sections. The ridges 112 and valleys 114 have a radius of curvature of 0.1 to 6 mm.

5 is a bottom view of the milling cutting insert shown in FIG. 1.

Referring to FIG. 5, the bottom surface 111 of the milling cutting insert 100 is a plane as a fastening reference surface which is firmly seated and fixed to the insert fixing seat of the tool holder when the milling cutting insert 100 is fixed to the tool holder. Is done. The bottom surface 111 and the major cutout side 150, the bottom surface 111 and the corner side surfaces 156 and 157, and the bottom surface 111 and the minor cutout side 154 are 60 to 90 degrees, preferably 65 to 85 degrees. At an angle. The angle of view makes the width of the upper surface 110 larger than that of the bottom surface 111, so that the pickling of the milling cutting insert 100 is primarily in contact with the workpiece during machining, and the interference between the side portion and the workpiece is processed. This is to prevent.

FIG. 6 is a cross-sectional view taken along the line A-A of FIG. 1.

Referring to FIG. 6, it can be seen that the inclined surface 120 of the main cut portion is shaped to have concave curvatures Rd and Rf and convex curvature Re. This is one of the important features of the present invention, when discharging the cutting chip cut by the milling process, so that the cutting chip slides smoothly through the convex surface and is not in contact with the concave portion. Thereby, the cutting heat which the cutting chip has is little conducted to the cutting insert 100, and the temperature rise of the cutting insert 100 is suppressed. As a result, it is possible to obtain a result of improving the life of the cutting insert 100 in cutting conditions with severe heat generation or processing of the workpiece.

FIG. 7 is a cross-sectional view taken along line B-B of FIG. 1.

Referring to FIG. 7, it can be seen that the inclined surface 130 of the lower limb is connected to the upper surface 110 while having a radius of curvature Ri.

FIG. 8 is a cross-sectional view taken along the line C-C of FIG. 1.

Referring to FIG. 8, it can be seen that the inclined surface 122 in the center of the main cutting part 140 is smoothly connected to the circular opening 101 having the curvature radii Rg and Rh.

9 is a cross-sectional view taken along the line D-D of FIG. 1.

Referring to FIG. 9, it can be seen that the inclined surface 120 around the major cutout has a concave curvature Rj and Rl and is connected very smoothly to the upper surface 124 having the convex curvature Rk. The convexity between the top surface 124 and the inclination between the inclined surfaces 120 serves to guide the formation of curls on the convex top surface 124 without the cutting chip proceeding to the opposite line. In addition, friction between the upper surface 124 of the convex curvature and the discharge chip is generated, and the space existing between the inclined curvature slope 120 and the cutting chip is not in contact with the discharge chip, especially when the cutting oil is used. Due to this, the cutting resistance between the milling cutting insert and the cutting chip is significantly reduced. As a result, an indirect contribution is made to the improvement of machinability, surface roughness and pickling strength, thereby improving tool life and quality.

As described above, the milling cutting insert 100 manufactured according to the present invention, unlike the conventional milling cutting insert having a straight cut portion, the shape of the cut portion 140 is at least three uneven curvature radius. By designing and using the inclined surface 120 of the main cutting portion in the concave-convex shape, it is possible to minimize the transfer of heat generated during cutting to the tool, it is possible to minimize the cutting resistance applied to the main cutting portion 140. In addition, the frictional resistance between the inclined surface 120 and the discharge chip is minimized to significantly improve the wear resistance of the cutting insert 100 and to improve the edge strength of the main cutting portion 140.

Therefore, the milling cutting insert 100 according to the present invention exhibits excellent tool life due to small cutting resistance, efficient chip ejection and excellent picking strength, etc. in the processing of low carbon steel, low carbon alloy steel having tough properties as well as general steel and alloy steel. . In addition, since it has a reasonable clearance angle and inclination angle, it exhibits remarkable performance in high speed and high feed processing of aluminum composite materials. In addition, the reduction of heat generation, which is a problem in the processing of stainless steel, hardened steel, etc., and the maintenance of pickling strength of the main cutting edge can significantly reduce the damage or chipping of the tool.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand that you can.

Claims (5)

In the milling cutting insert, which includes an upper surface and a lower surface and is used by mounting to a milling cutter, At least one major cutout, a minor cutout, a lower cutout, and a first edge cutout and a second corner cutout, each provided at two corners of the upper surface to be symmetrical in a diagonal direction, wherein the major cutout is in the upper surface; Extends between the first and second corner cutouts so as to have at least three uneven curvature radii at a boundary position between the main cutout side and an inclined surface of the main cutout part, forming an uneven surface. It is formed to extend toward the center of the surface, the uneven surface has a radius of curvature of 0.1 ~ 6mm, the major cutting portion includes the main cutting and the main land surface having different curvature, the main cutting It consists of phosphorus, the second main clause, the third main temple, the fourth main temple and the fifth main temple, wherein the first main temple and the fifth main temple And, the second and the fourth main clause of the main clause is concave in the main clause, milling cutting insert, it characterized in that the third main clause of the main clause is a convex. The milling cutting insert of claim 1, wherein the milling cutting insert further comprises a central opening formed by vertically penetrating the center of the milling cutting insert. The center cutout of claim 1, wherein the second main cutout and the fourth main cutout have a radius of curvature of 10 to 50 mm, the third main cutout has a radius of curvature of 10 to 60 mm, and a center position of the third main cutout. Milling cutting insert, characterized in that placed between the 1/4 to 3/4 of the length of the major cutout. 2. The milling cutting insert according to claim 1, wherein said major land surfaces have an area of 0.01 to 0.5 mm and a land angle of -25 to +30 degrees. According to claim 1, wherein the cutting edge side has a clearance angle of 30 degrees or less with respect to the cutting edge, the main cutting edge side is the first side partition is a reference side, the second side partition is a side of the concave curvature, and And a third side section faced at a constant slope, said first side section being planar, said second side section having a clearance angle less than said first side section.