JP2009050950A - End mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an end mill which eliminates clogging with cutting chips, by enlarging a chip pocket formed in a rake face of a long blade having no nick on a bottom blade and by improving its chip discharging performance even if a workpiece is made of a rolled material, and smoothly shifts its operation from hole machining to groove machining without breakage of a short blade having a nick formed at a location that is moved through 120° counterclockwise from the long blade, or without breakage of the end mill itself at the time of shifting its operation from the hole machining to the groove machining. <P>SOLUTION: The end mill has the two bottom blades of the long blade 4 for machining from a periphery 2 to a central portion 3, and the short blade 5 which is located at a location moved through 240° counterclockwise from the long blade 4 and machines only a peripheral portion in the range of 1/3 or more of the radius of the end mill. According to the structure of the end mill, the bottom blade is cut out at a location that is moved through 120° counterclockwise from the long blade 4, and therefore only a peripheral blade 7 that omits the short blade is formed at the location. Thus, the end mill has the two bottom blades, the long blade 4 of which has the enlarged chip pocket formed in the rake face, and three side blades. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an end mill capable of drilling a material having high ductility and difficult to cut chips, and capable of shifting to grooving.

Patent Document 1 describes an end mill in which an axial nick is provided on one or more bottom blades. As a result, the chips are cut, and the breakage due to chipping of the corner portions and chipping is eliminated.
JP 2005-219176 A

  However, in Patent Document 1, in drilling a material having high ductility and difficult to cut chips, there are more chips of long blades that do not have bottom blade nicks than short blades that have bottom blade nicks. Chips were generated on the rake face of the long blade, and the short blade provided with the nick provided at a position moved 120 ° counterclockwise from the long blade could be damaged. Further, even if the short blade is not damaged, there is a problem that if the grooving is performed with the chips clogged on the rake face of the long blade, the end mill breaks when the grooving is performed.

  The object of the present invention is to improve the bottom blade of an end mill having an axial nick on one or more of the bottom blades of Patent Document 1, and to increase the chip pocket on the rake face of the long blade that does not have the bottom blade nick. Short blade with a nick provided at a position 120 ° counterclockwise from the long blade to improve chip discharge and prevent chipping or clogging even when drilling a material that is difficult to divide. It is an object to provide an end mill capable of performing grooving from hole drilling without breakage of the end mill or breakage of the end mill when shifted to grooving.

  For this reason, the present invention is based on a high-speed tool steel, a powder high-speed tool steel, cemented carbide, ultrafine cemented carbide, or ultrafine particulate cemented carbide containing 6 to 14% cobalt, respectively. In the single-blade coated end mill, the bottom blade is a long blade that processes from the outer periphery to the center, and only the outer periphery that is more than 1/3 the radius of the end mill is moved to a position that is 240 ° counterclockwise from the long blade. Two outer blades having two bottom blades of a short blade, a chip pocket on the rake face of the long blade, and a torsion angle of the groove groove following the two bottom blades on the outer periphery of the end mill; At the position moved 120 ° from the long blade, there are two bottom blades and three outer blades provided with one outer blade having a blade groove torsion angle in which the bottom blade is cut and the short blade is eliminated. By providing an end mill characterized in that It solved the problem.

  With this configuration, the bottom blade is a long blade that processes from the outer periphery to the center, and a short blade that processes only the outer periphery within the range of 1/3 or more of the radius of the end mill at a position 240 ° counterclockwise from the long blade. There are two bottom blades, and the bottom blade is cut by an arc line close to a straight line passing through the center of rotation of the bottom blade at a position moved 120 ° counterclockwise from the long blade, eliminating the short blade. Only the outer peripheral blade is provided, the tip pocket of the rake face of the long blade is enlarged, and the outer periphery of the end mill has a groove groove twist angle following the two bottom blades. Has two bottom blades and three outer peripheral blades with one peripheral blade having a groove groove helix angle where the bottom blade is cut to eliminate the short blade, so the chip pocket on the rake face of the long blade Even when drilling holes in materials that are highly ductile and difficult to break up chips, In other words, there is no breakage, and there is no breakage of the short blade provided with the nick provided at the position moved 120 ° counterclockwise from the long blade, or breakage when moving to grooving. From this, an end mill capable of performing grooving was provided.

Preferably, the cut bottom blade at a position moved by 120 ° counterclockwise from the long blade is an arc line close to a straight line passing through the rotation center of the bottom blade or a curvature equal to or greater than the radius of the end mill passing through the rotation center of the bottom blade. The bottom blade is cut by a circular arc line of radius, and the length of the outer peripheral blade cut by cutting the bottom blade is set to be within the end mill radius and less than 1/3 of the end mill radius. The chip pocket on the rake face can be secured sufficiently, chipping is not generated during drilling, and the short blade with a nick provided at a position moved 120 ° counterclockwise from the long blade is damaged. In addition, the present invention provides an end mill that does not cause breakage when shifting to grooving and can perform grooving from hole machining even with a ductile material. If the length of the cut outer peripheral blade at a position moved 120 ° from the long blade exceeds the end mill radius, the volume processed by the long blade on the side surface will increase, and the chips will scratch the work surface and the cutting balance will be poor. As a result, chattering occurs and the machined surface deteriorates. In addition, if the radius of curvature of the arc line cutting the bottom blade is less than 1/3 of the end mill radius, chip clogging occurs because the chip pocket is not large enough.
More preferably, in the above-mentioned end mill, if each cutting edge portion is coated with 0.5 to 5 μm of carbide or nitride in one layer or two layers or more, it prevents the occurrence of chip welding and further prevents the chips from clogging. Become. The present invention can be applied to an end mill having an outer diameter of 3 mm to 30 mm.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1A is a side view of an end mill according to an embodiment of the present invention, FIG. 1B is an enlarged bottom view of the end mill viewed from the bottom blade side of FIG. Side view of outer peripheral blades 7 and 7a in which the bottom blade is cut by an arc line with a large radius of curvature R1 close to the straight line shown by the broken line passing through the rotation center of the bottom blade of the end mill at a position moved 120 ° in the direction to eliminate the short blade (B) is a side view of the outer peripheral blades 7 and 7b cut by an arc line having a radius of curvature R2 of the end mill passing through the center of rotation, and (c) is a radius of curvature R3 less than 1/3 of the end mill diameter passing through the center of rotation. FIG. 3 shows side views of the outer peripheral blades 7 and 7c cut by the circular arc line of FIG. 3, and FIG. 3 shows the length of the outer peripheral blade cut by cutting the bottom blade at a position moved 120 ° counterclockwise from the long blade 4. It is a side view of the end mill which shows length W.

  As shown in FIG. 1, the end mill according to the embodiment of the present invention includes a high-speed tool steel, a powder high-speed tool steel, cemented carbide, ultrafine cemented carbide, A three-blade coated end mill 1 with a fine cemented carbide as the base material. The bottom blades 4 and 5 are 240 ° counterclockwise from the long blade 4 and the long blade 4 that machine from the outer periphery 2 to the center 3. At the moved position, there are two bottom blades, short blade 5 that processes only the outer periphery in the range of 1/3 or more of the radius of the end mill. From the long blade 4 counterclockwise as shown in Fig. 2 (a) Only the outer peripheral edge 7a in which the bottom edge is cut by an arc line close to the straight line shown by the broken line passing through the center of rotation of the bottom edge and the short edge is eliminated is provided at the position moved 120 ° in the direction. Two outsides having a larger insert pocket 42 and an outer periphery of the end mill that has a twist angle of the blade groove following the two bottom blades 4 and 5 Two bottom blades 4, 5 and three outer peripheries provided with blades 6, 6 and one outer peripheral blade 7 having a blade groove torsion angle without a bottom blade at a position moved 120 ° from the long blade. This is an end mill that has blades 6, 6, and 7, eliminates the short blade following the long blade 4 of the bottom blade, has two bottom blades and three side blades.

  As shown in FIG. 3, the end mill of the embodiment of the present invention has a length of the outer peripheral blade 7 cut by cutting the cut bottom blade at a position moved 120 ° counterclockwise from the long blade 4. W is set to a radius less than the end mill radius and more than 1/3 of the radius of the end mill, and the chip pocket 42 of the rake face 41 of the longer blade 4 can be secured sufficiently, as in the end mill of FIG. In the outer peripheral blade 7c cut by an arc line having a radius of curvature less than 1/3 of the end mill diameter passing through the rotation center indicated by the broken line, the outer peripheral blade 7c becomes an acute angle and the strength decreases. Further, if each cutting edge portion is coated with 0.5 to 5 μm of carbide or nitride in one layer or two or more layers, the occurrence of chip welding is prevented and the chips are not easily clogged. The present invention can be applied to an end mill having an outer diameter of 3 mm to 30 mm.

  Drilling is performed on a 5 mm thick S10C plate with a carbide end mill with an outer diameter of 6 mm, a blade length of 13 mm, and a length of 60 mm, which is the product of the present invention. Each of the long blades 4 shown in FIG. ° The length W of the outer peripheral blade cut by cutting the bottom blade at the moved position is 3 mm, and the radius of curvature close to a straight line with a radius length of 6 mm passing through the center of rotation as shown in FIG. Carbide end mill with outer peripheral edge cut by arc line, end carbide end mill with outer radius cut by arc line with 3mm radius of curvature passing through the center of rotation shown in Fig. 2 (b), and comparative product The damage state of each of the carbide end mills of the outer peripheral edge cut with an arc wire having a radius of curvature of less than 1/3 of the end mill diameter passing through the center of rotation shown in FIG.

  The state of damage of each carbide end mill is the product of the present invention. In the carbide end mill shown in FIGS. 2 (a) and 2 (b), there is no chipping in the chip pocket on the rake face of the long blade 4. However, in the carbide end mill shown in FIG. 2 (c), which is a comparative product, chipping occurred in the chip pocket on the rake face of the long blade 4.

  Drilling is performed on a 5 mm thick S10C plate with a carbide end mill with an outer diameter of 6 mm, a blade length of 13 mm, and a length of 60 mm, which is the product of the present invention, and 120 ° counterclockwise from the long blade 4 shown in FIG. The length W of the outer peripheral blade cut by cutting the bottom blade at the moved position is set to 0.5 mm (Comparative product 1), 1 mm, 3 mm, and 5 mm (Comparative product 2), respectively. The state of damage and the state of the machined surface of each cemented carbide end mill when cutting with an arc line having a radius of curvature of 3 mm and passing through the center of rotation as shown in 2 (b) was investigated.

  The state of damage of each carbide end mill is the rake of the long blade 4 in the carbide end mill in which the length W of the cut outer peripheral blade shown in FIG. 3 is set to 1 mm and 3 mm, respectively. Chips were not generated in the chip pocket on the surface, but in the carbide end mill (Comparative product 1) with the outer peripheral blade length W set to 0.5 mm, chips in the chip pocket on the rake face of the long blade 4 In other words, the carbide end mill (Comparative Product 2) with the outer peripheral blade length W set to 5 mm was chattered and the machined surface deteriorated.

Figure 4 shows a carbide end mill with an outer diameter of 6 mm, a blade length of 13 mm, and a 60 mm carbide end mill, and a conventional three-blade carbide blade with a bottom blade when grooving after drilling a 5 mm thick SS400 plate. The end mill (three blades) of the present invention and the length W of the outer peripheral blade cut by cutting the bottom blade at a position moved 120 ° counterclockwise from the long blade 4 shown in FIG. Carbide end mills (bottom 2 blades, outer 3 blades) cut with an arc line with a radius of curvature of 3mm and an end mill radius set to 3mm and passing through the center of rotation as shown in Fig. 2 (b). These are comparisons of the number of grooves processed when each is continuously processed. As shown in Fig. 4, the carbide end mill with two bottom blades of the present invention, which has two blades, was able to machine 100 grooves (discontinued after 100 grooves), whereas In the end mill with 3 blades at the bottom edge, chipping occurred in front of the long blade at the 15th groove and broke.
[Effect of Best Embodiment of the Present Invention]

  As described above, according to the configuration of the best embodiment of the present invention, the end mill of the present invention has a bottom blade that is moved from the outer periphery to the central portion by a long blade and the long blade is moved by 240 ° counterclockwise. It has two bottom blades, a short blade that only processes the outer periphery of the end mill radius in the range of 1/3 or more at the position, and the bottom blade is located at a position moved 120 ° counterclockwise from the long blade. Only the outer peripheral blade with the bottom blade cut by a circular arc line passing through the center of rotation to eliminate the short blade is provided, the chip pocket on the rake face of the long blade is enlarged, and the blade following the two bottom blades on the outer periphery of the end mill Two outer peripheral blades having a groove twist angle and two outer peripheral blades and two outer blades provided with one outer peripheral blade having a blade groove twist angle in which the bottom blade is cut and the short blade is eliminated at a position moved 120 ° from the long blade. Since it has a bottom blade and three outer peripheral blades, it is necessary to ensure a sufficient chip pocket on the rake face of the long blade. Even when drilling a material that is highly ductile and difficult to separate chips, no chipping occurs, and as a result, a short blade with a nick provided at a position that is moved 120 ° counterclockwise from the long blade. An end mill capable of performing grooving from drilling even with a ductile material that does not break or break when transferred to grooving is provided.

Preferably, the cut bottom blade at a position moved by 120 ° counterclockwise from the long blade is an arc line close to a straight line passing through the rotation center of the bottom blade or a curvature equal to or greater than the radius of the end mill passing through the rotation center of the bottom blade. The bottom blade is cut by a circular arc line of radius, and the length of the outer peripheral blade cut by cutting the bottom blade is set to be within the end mill radius and less than 1/3 of the end mill radius. The chip pocket on the rake face can be secured sufficiently, chipping is not generated during drilling, and the short blade with a nick provided at a position moved 120 ° counterclockwise from the long blade is damaged. In addition, the present invention provides an end mill that does not cause breakage when shifting to grooving and can perform grooving from drilling even with a ductile material. If the length of the cut outer peripheral blade at a position moved 120 ° from the long blade exceeds the end mill radius, the volume processed by the long blade on the side surface will increase, and the chips will scratch the work surface and the cutting balance will be poor. As a result, chattering occurs and the machined surface deteriorates. If the radius is less than 1/3 of the end mill radius, chip pockets are generated because the chip pocket is not large enough.
More preferably, in the above-mentioned end mill, if each cutting edge portion is coated with 0.5 to 5 μm of carbide or nitride in one layer or two layers or more, it prevents the occurrence of chip welding and further prevents the chips from clogging. Become. The present invention can be applied to an end mill having an outer diameter of 3 mm to 30 mm.

(A) is a side view of a three-blade carbide coated end mill of the best mode for carrying out the present invention, and (b) is a bottom view showing the shape of the bottom blade of (a). (A) is a short blade in which the bottom blade is cut by an arc line close to a straight line indicated by a broken line passing through the rotation center of the bottom blade of the end mill at a position moved 120 ° counterclockwise from the long blade 4 in FIG. 1 (b). (B) is a side view of the outer peripheral blades 7 and 7b cut by an arc line having a radius of curvature of the end mill radius passing through the rotation center, and (c) is an end mill passing through the rotation center. Side views of the peripheral blades 7 and 7c cut by an arc line having a radius of curvature less than 1/3 of the diameter are shown. FIG. 5 is a side view of the end mill showing the length W of the outer peripheral blade cut by cutting the bottom blade at a position moved 120 ° counterclockwise from the long blade 4. It is a graph which shows the comparison of the number of processing grooves when carrying out continuous processing with the carbide end mill of the present invention product (bottom blade 2 blades) and the conventional product (bottom blade 3 blades) of Example 3.

Explanation of symbols

1: 3-flute carbide coated end mill, 2: outer periphery, 3: central part, 4: long blade (bottom blade)
5: Short blade (bottom blade), 6: Peripheral blade following the bottom blade, 7, 7a, 7b, 7c: Perimeter blade with the bottom blade cut
41: Rake face of long blade, 42: Tip pocket, R1, R2, R3: Radius of curvature W: Length of the outer peripheral blade cut by cutting the bottom blade

Claims (3)

  High-speed tool steel, powder high-speed tool steel, a three-blade coated end mill containing 6 to 14% cobalt, each of which is made of cemented carbide, ultrafine particle cemented carbide, or ultrafine particle cemented carbide. The bottom blade consists of two blades: a long blade that processes from the outer periphery to the center, and a short blade that processes only the outer peripheral portion within 1/3 of the radius of the end mill at a position 240 ° counterclockwise from the long blade. The outer peripheral edge of the long blade, the chip pocket of the rake face of the long blade is enlarged, and the outer periphery of the end mill has a groove groove twist angle following the two bottom blades, and 120 ° from the long blade. An end mill having two bottom blades and three outer peripheral blades provided with one outer peripheral blade having a blade groove twist angle in which the bottom blade is cut and the short blade is eliminated at the moved position .   The cut bottom blade at a position moved 120 ° counterclockwise from the long blade is an arc line close to a straight line passing through the rotation center of the bottom blade or a circle having a radius of curvature equal to or greater than the radius of the end mill passing through the rotation center of the bottom blade. The bottom blade is cut by an arc wire, and the length of the outer peripheral blade cut by cutting the bottom blade is set to be not more than the end mill radius and not less than 1/3 of the end mill radius. 1 is an end mill.   3. The end mill according to claim 1 or 2, wherein each cutting edge portion is coated with 0.5 to 5 [mu] m of carbide or nitride in one layer or two or more layers.

Images