JP2005297107A - Radius end mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radius end mill capable of setting a round working range angle of a round corner blade to 90° or more without generating a step height of a connecting part between a round corner blade flank and an outer peripheral flank, in the radius end mill for performing precision processing of a die. <P>SOLUTION: This radius end mill has a twisted outer peripheral blade 3 formed of the outer peripheral flank 4, and the round corner blade flank 2 for forming a circular arc-shaped round corner blade 1. A circular arc blade is formed by setting the round working range angle of the round corner blade 1 to 100° (preferable at 90° or more), by eliminating the step height of the connecting part 5 between the round corner blade flank 2 and the outer peripheral flank 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an improvement in a radius end mill having a torsional outer peripheral blade formed by an outer peripheral flank and a round corner blade flank forming an arcuate round corner blade that performs precision machining in mold processing.

Conventionally, a ball end mill is generally used for three-dimensional processing of a mold or the like. However, with a conventional ball end mill, uniform cutting performance cannot be obtained over the entire circumference of the ball, and in particular, the cutting speed is 0 (zero) at the center of the rotation, and the processing site may be peeled off. Or by reducing the depth of cut. On the other hand, in place of the ball end mill, there is a large demand for shortening the machining time in recent years. Radius end mills have been widely used. Unlike ball end mills, radius end mills with round corner edges can be easily drilled and tilted, and the removal volume is large in areas close to a flat surface, enabling high-efficiency machining. In addition, since the cutting speed is 0 to MAX in the ball end mill, the machining surface accuracy varies, but in the radius end mill, the cutting speed difference in the radial direction of the round corner blade is small, so a stable machining surface is obtained compared to the ball end mill. Therefore, the use in the mold field is increasing as a processing method replacing the ball end mill. In particular, when a 5-axis machine is used, the effect is said to be great. For example, Patent Document 1 discloses a radius end mill in which at least one of the bottom blades is a medium to low cutting edge reaching the rotation center and the bottom angle of the bottom blade is 5 degrees or more in order to increase the cutting edge strength. .
JP-A-11-216609

  However, as shown in FIG. 6, the radius end mill of Patent Document 1 is formed by a round corner blade 11 formed by a round corner blade flank, an outer peripheral blade 13 formed by an outer flank and a bottom blade flank. The bottom blades 16 are all manufactured in a separate process, and a step is generated in each connecting portion 15. Also, in order to avoid biting of the grindstone into the outer peripheral edge 13 and the bottom edge 16, even if the design cutting edge angle of the round corner edge 11 is 96 °, in order to avoid these joints during actual mold processing, The corner blade construction range angle is 70-80 °, and more generally, the tolerance of the distance between the edge shape of the round corner blade 11 and the round corner radius R (round corner blade R accuracy) is ± 10μm accuracy. . Therefore, a step is generated in the connecting portion 15 between the round corner blade flank and the outer peripheral flank, and uncut or overcutting occurs on the machining side or bottom. For this reason, since the round corner edge R accuracy deviates from the ideal, ie, design, round corner edge shape, the machined surface is overcut (overcut) or sharpened against the ideal, ie, design, finished surface. Leftover occurs. If overcutting, the product becomes NG, and for uncut parts, the incision is changed and the cutting is performed again. Since it takes a long time, the processing cost increases.

  The object of the present invention is to solve the problems of the prior art, in a radius end mill that performs precision machining in die machining, so as not to cause a step in the joint between the round corner blade flank and the outer flank, The object of the present invention is to provide a radius end mill that allows the round construction angle of the round corner blade to be 90 ° or more.

  Therefore, according to the present invention, in a radius end mill having a torsional outer peripheral blade formed by 2 to 10 outer peripheral flank surfaces and a round corner blade flank surface forming an arcuate round corner blade, The above-described problems of the present invention have been solved by a radius end mill characterized in that the step angle of the connecting portion between the round corner blade flank is eliminated and the R construction range angle of the round corner blade is 90 ° or more.

  In the present invention, the R construction range angle of the round corner blade is set to 90 ° or more by eliminating the step at the connecting portion between the round corner blade flank and the outer peripheral flank. There is no need for overcutting (overcutting) or uncutting on the finished surface above, changing the incision, recutting, or spending a lot of time on the polishing process and increasing the processing cost. There was no radius end mill provided.

  The best mode for carrying out the present invention will be described with reference to FIG. FIG. 1 shows the best mode for carrying out the present invention, a twisted outer peripheral blade 3 formed by four (or 2 to 10) outer peripheral flank surfaces having an outer diameter D = φ10 mm, and R2 mm. The side view of the carbide | carbonized_material carbide end radius mill which has the round corner blade flank 2 which forms the circular arc-shaped round corner blade 1 is shown. A step of the connecting portion 5 between the round corner blade flank 2 and the outer peripheral flank 4 and a step of the connecting portion 5 between the round corner blade flank 2 and the bottom blade flank 7 forming the bottom blade 6; Is a carbide and carbide coated radius end mill in which the R construction range angle 9 of the round corner blade 1 is 100 ° (may be 90 ° or more). Even if there is a step in the connecting portion 5 between the round corner blade flank 2 and the bottom blade flank 7 forming the bottom blade 6, the R construction range angle 9 of the round corner blade 1 is 90 ° or more. I just need it.

  In the radius end mill of FIG. 1, in order to smoothly connect the outer peripheral flank 4 and the round corner blade flank 2, the bottom blade margin angle 8 is set to 6 ° (may be 2 ° to 10 °). The R accuracy, which is the tolerance of the distance between the shape of the round corner blade 1 and the round corner radius R, is ± 3 μm, the tool material is ultra-fine cemented carbide containing 10% cobalt, and the cutting edge surface. Was coated with 3 μm of titanium nitride aluminum hard film.

  As shown in FIG. 2, the step of the joint portion 5 between the outer peripheral blade 3 and the arc-shaped round corner blade 1 and the step of the joint portion 5 between the round corner blade 1 and the bottom blade 6 are eliminated. Therefore, after the outer peripheral flank 2 is first machined, the round grinder blade flank 4 and the bottom flank flank 7 in the same NC program (not shown) are continuously processed with the same grindstone (not shown). By machining the corner blade flank 4 and the bottom blade flank 7, the steps of the connecting portions 5 were eliminated.

The carbide coated radius end mill of the present invention with the outer diameter D = φ10 mm 4-flute round corner blade R2 mm shown in FIG. 1 and the comparison product of the conventional product with an outer diameter D = φ10 mm, 4-flute round corner blade R2 mm. A machining accuracy comparison test with a carbide coated radius end mill (conventional product) was performed by scanning line machining on a vertical wall 85 ° surface as shown in FIG. 4 using a vertical MC (BT50). Cutting conditions were as follows: Pre-hardened steel NAK80 (40 HRC), cutting speed 150m / min (rotation speed 4,800min- ¹ ), table feed speed 2,200mm / min (f = 0.115mm / t), axial cutting 0.4 The scanning line was processed by dry (air blow) with a notch of 0.5 mm and a radial cut of 0.5 mm. FIG. 5 shows the machining surface accuracy at this time. In contrast to the ideal, i.e., design, machined surface of the conventional product, an uncut portion of about 8 μm is generated, whereas the product of the present invention was machined according to the ideal machined surface. FIG. 6 is an explanatory diagram for comparing the machined surface accuracy of FIG. The dotted line indicates the machined surface of the product of the present invention. In the conventional product, an uncut portion of about 8 μm is generated, whereas the product of the present invention was machined according to the ideal curved surface.

Preferably, as shown in FIGS. 4A and 5, the tolerance of the distance between the shape of the round corner blade and the center of the round corner radius R is within ± 3 μm.
More preferably, in order to smoothly connect the round corner blade flank and the bottom blade flank, it is desirable that the bottom blade watermark angle 8 is 2 ° to 10 °.

  As described above, in the best mode for carrying out the present invention, the stepped portion of the connecting portion between the round corner blade flank and the outer peripheral flank is eliminated, and the R construction range angle of the round corner blade is 90 °. Since it is above °, the machined surface does not cause overcutting (overcutting) or uncut residue on the ideal finished surface, that is, the designed finished surface. It became a radius end mill that did not require much time to increase the processing cost.

The side view of (phi) 10mm 4 blade round corner blade R2mm super hard carbide coated radius end mill of the best form for implementing this invention is shown. It is a principal part enlarged view of the round corner blade shape of the product shown in FIG. It is a perspective view which shows the workpiece processing state by the invention product shown in FIG. 1, and a conventional product. It is a comparison of machined surface accuracy between the invention product and the conventional product. It is an explanatory view of the machined surface accuracy comparison between the invention product and the conventional product. It is a principal part enlarged view of the round corner blade shape of a conventional product.

Explanation of symbols

1: Round corner blade 2: Round corner blade flank 3: Outer peripheral blade 4: Outer peripheral flank 5: Joint part 6: Bottom blade 7: Bottom blade 8: Bottom blade corner angle 9: R construction range angle of round corner blade

Claims (6)

  In a radius end mill having a twisted outer peripheral blade formed by 2 to 10 outer peripheral flank surfaces and a round corner blade flank surface forming an arcuate round corner blade, the outer peripheral flank surface and the round corner blade flank surface A radius end mill characterized in that the R construction range angle of the round corner blade is set to 90 ° or more by eliminating a step in the connecting portion.   After processing the outer peripheral flank first, the outer peripheral flank is processed by continuously processing the round corner blade flank with the same grindstone using the round corner blade flank machining program in the same NC program. The radius end mill according to claim 1, wherein a step at a joint portion between the flank and the round corner blade flank is eliminated.   In a radius end mill having a twisted outer peripheral blade formed by 2 to 10 outer peripheral flank surfaces and a round corner blade flank surface forming an arcuate round corner blade, the round corner blade flank surface and the outer peripheral flank surface The R corner of the round corner blade has an angle of 90 ° or more by eliminating the step of the joint portion and the step of the joint portion between the round corner blade clearance surface and the bottom blade clearance surface forming the bottom blade. Radius end mill characterized by that.   After machining the outer peripheral flank first, the round corner blade flank and bottom blade are continuously processed by the same grinding wheel with the machining program for the round corner blade flank and bottom blade flank within the same NC program. By machining the flank, the step of the joint between the outer peripheral flank and the round corner blade flank, and the step of the joint between the round corner blade flank and the bottom blade flank, The radius end mill according to claim 3, wherein each of them is eliminated.   The radius end mill according to any one of claims 1 to 4, wherein a tolerance of a distance between a shape of the round corner blade and a center of the round corner radius R is within ± 3 µm.   6. The bottom blade watermark angle is set to 2 ° to 10 ° in order to smoothly connect the round corner blade flank and the bottom blade flank. 6. Radius end mill.

Images