JP2006035377A - Ball end mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems that (1) it is difficult to control the revolving speed and feed speed in curved surface processing, in which "erected walls" and "flat portions" are mixed, in accordance with the state of cutting process using an end mill and (2) it is also difficult to keep a cutting point constant when carrying out cutting process while maintaining the relative angle between the cutting surface and the tool so as not to change the cutting points (circumferential speed), because priority is given to averting mutual interference of the tool and work. <P>SOLUTION: The ball end mill 1 is provided with a tip portion 10, equipped with effective blades, and a side end portion 11, formed sequentially to the tip portion 10 and also equipped with effective blades. The number of blades on the tip portion 10 is made larger than that of blades on the side end portion 11. Effective blades are composed of principal blades 2 and subordinate blades 3 having a diameter smaller than that of principal blades 2, and the number of principal blades 2 installed on the tip portion 10 is made larger than that of principal blades 2 on the side end portion 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a configuration of an end mill used for cutting. More specifically, the present invention relates to an end mill shape for suppressing chattering in cutting using an end mill and performing cutting efficiently.

The ball end mill is often used when it is desired to create in a short time in three-dimensional curved surface processing such as mold making, and the demand for high-speed cutting using a ball end mill is particularly strong. The ball end mill has an advantage that an arc radius with high accuracy can be provided by grinding the arc radius of the ball blade with a nose as a base point.
And in order to implement | achieve highly efficient process, increasing the number of blades and making it multi-blade and making a chip small are performed. In addition, various cutting edge attempts have been made, and the cutting edge has been devised with regard to dischargeability and the twist amount has been devised in order to solve the reduction in chip pockets associated with the increase in the number of cutting edges.

In the structure of a multi-blade ball end mill, there is known a structure composed of a plurality of outer peripheral blades having a twist and a ball blade and comprising a master blade that reaches the nose and a slave blade that does not reach the nose (for example, Patent Document 1). ).
Further, a soft material cutting tool is also known in which a spiral outer peripheral blade is formed on the outer periphery of the body portion of the tool body, and a tip shape having a number of cutting blades provided at the distal end portion (for example, Patent Document 2).
Japanese Patent Laid-Open No. 10-80816 Japanese Utility Model Publication No. 6-50719

In the conventional multi-blade tool, chatter vibration is likely to occur during machining with a long protruding amount. “Standing wall” machining, in which machining is performed near the end on the tool side, is liable to generate chatter, and in order to suppress this chatter vibration, it is necessary to control the rotation speed of the tool to lower the tool rotation speed. Particularly in the processing of the corner-shaped portion, it is necessary to control the amount of feed per blade in accordance with this in order to reduce the tool rotation speed. For this reason, the feed rate of the tool cannot be increased, and the time required for cutting increases.
On the other hand, in the “flat portion” machining in which machining is performed in a portion close to the tool tip, the peripheral speed of the tool is extremely small compared to the side edge (the peripheral speed is 0 at the rotation center of the tip). It becomes close to drag processing. For this reason, the processing which raises the number of rotations as much as possible, actively creates chips and reduces the cutting load is desired.
However, in curved surface shape machining where “standing wall” and “flat part” coexist, it is necessary to control the rotation speed and feed speed according to the machining situation, and complicated control of the tool rotation speed and feed amount is required. It will be required, and it is difficult to perform the cutting work. In order to perform “simultaneous 5-axis machining” that maintains the relative angle between the cutting surface and the tool so that the cutting point (peripheral speed) does not change, priority is given to avoiding interference between the tool and the workpiece, and the cutting point is kept constant. It is very difficult to keep it at a high level.

In the technique disclosed in Patent Document 1, the number of blades at the tip and the number of blades at the side are the same, and it is difficult to balance the load on the tip and the load on the side. Depending on the situation, complicated adjustment of the rotation speed and feed rate is required.
And in the technique shown by patent document 2, the cutting object is a soft material, and one helical peripheral blade is provided in a side part, and when using about a metal material, it is not suitable. .

  In order to solve the above problems, in the present invention, a ball end mill having a small number of blades at the tool side end portion where the peripheral speed of the rotary cutting tool is large and a large number of blades at the tool tip portion where the peripheral speed is small is provided. It constitutes. This enables processing with reduced chatter vibration in deep drilling with a tool having a long protrusion.

  That is, as described in claim 1, a ball end mill that includes a plurality of blades at a tip portion and a side end portion provided following the tip portion, wherein a part of the blade is configured to be small at the side end portion. The number of blades at the tip is made larger than the number of blades at the side edge.

  3. A ball end mill comprising an effective blade as a leading end portion and a side end portion provided following the leading end portion according to claim 2, wherein the effective blade is a main blade and a secondary blade having a smaller diameter than the main blade. And the number of main blades provided at the tip end portion is larger than the number of main blades provided at the side end portions.

  As described in claim 3, a portion from the tip of the effective blade to a certain distance in the axial direction is defined as a tip portion, and a portion subsequent to the tip portion of the effective blade is defined as a side end portion.

  As described in claim 4, in the effective blade, a portion where the peripheral speed of the blade is equal to or less than a predetermined value is defined as a tip portion, and a portion where the peripheral speed of the blade is faster than the predetermined value is defined as a side end portion.

  As described in claim 5, in a side view of the effective blade, a portion where the angle formed between the axis and the blade tangent is a predetermined value or more is a tip portion, and the angle formed between the axis and the blade tangent is smaller than the fixed value. Let the part be the side edge.

  7. A ball end mill in which the effective blade is constituted by a tip portion and a side end portion provided subsequent to the tip portion as in claim 6, wherein the effective blade is constituted by a main blade and a sub blade, and the tip portion The difference between the diameter of the main blade and the diameter of the sub blade is larger than the difference between the diameter of the main blade and the diameter of the sub blade.

A ball end mill comprising a plurality of blades as a tip portion and a side end portion provided subsequent to the tip portion, wherein a part of the blade is configured to be small at the side end portion. Since the number of blades at the part is larger than the number of blades at the side edge,
In the ball end mill, the number of blades simultaneously hitting the cutting surface can be reduced, and chatter of the ball end mill can be suppressed. Thereby, the processing accuracy using a ball end mill can be improved. In addition, even during the “standing wall” processing, it is not necessary to drastically reduce the feed rate and the rotation speed, and the time required for processing can be reduced. In the “flat portion” processing by the tip portion, chattering of the end mill hardly occurs even if the rotational speed is increased, and the rotational speed of the ball end mill can be easily set.

3. A ball end mill comprising an effective blade as a leading end portion and a side end portion provided following the leading end portion according to claim 2, wherein the effective blade is a main blade and a secondary blade having a smaller diameter than the main blade. Since the number of main blades provided at the tip end portion is larger than the number of main blades provided at the side end portions,
In the ball end mill, the number of blades simultaneously hitting the cutting surface can be reduced, and chatter of the ball end mill can be suppressed. Thereby, the processing accuracy using a ball end mill can be improved. In addition, even during the “standing wall” processing, it is not necessary to drastically reduce the feed rate and the rotation speed, and the time required for processing can be reduced. In the “flat portion” processing by the tip portion, chattering of the end mill hardly occurs even if the rotational speed is increased, and the rotational speed of the ball end mill can be easily set.

As described in claim 3, since the tip portion is a certain distance in the axial direction from the tip of the effective blade, and the portion after the tip portion of the effective blade is a side end portion,
In the ball end mill, the number of blades simultaneously hitting the cutting surface can be reduced, and chatter of the ball end mill can be suppressed. Thereby, the processing accuracy using a ball end mill can be improved. In addition, even during the “standing wall” processing, it is not necessary to drastically reduce the feed rate and the rotation speed, and the time required for processing can be reduced. In the “flat portion” processing by the tip portion, chattering of the end mill hardly occurs even if the rotational speed is increased, and the rotational speed of the ball end mill can be easily set.

As described in claim 4, in the effective blade, a portion where the peripheral speed of the blade is a constant value or less is a tip portion, and a portion where the peripheral speed of the blade is faster than the constant value is a side end portion.
In the ball end mill, the number of blades simultaneously hitting the cutting surface can be reduced, and chatter of the ball end mill can be suppressed. Thereby, the processing accuracy using a ball end mill can be improved. In addition, even during the “standing wall” processing, it is not necessary to drastically reduce the feed rate and the rotation speed, and the time required for processing can be reduced. In the “flat portion” processing by the tip portion, chattering of the end mill hardly occurs even if the rotational speed is increased, and the rotational speed of the ball end mill can be easily set.

As described in claim 5, in a side view of the effective blade, a portion where the angle formed between the axis and the blade tangent is a predetermined value or more is a tip portion, and the angle formed between the axis and the blade tangent is smaller than the fixed value. Because the part is the side edge,
In the ball end mill, the number of blades simultaneously hitting the cutting surface can be reduced, and chatter of the ball end mill can be suppressed. Thereby, the processing accuracy using a ball end mill can be improved. In addition, even during the “standing wall” processing, it is not necessary to drastically reduce the feed rate and the rotation speed, and the time required for processing can be reduced. In the “flat portion” processing by the tip portion, chattering of the end mill hardly occurs even if the rotational speed is increased, and the rotational speed of the ball end mill can be easily set.

7. A ball end mill in which the effective blade is constituted by a tip portion and a side end portion provided subsequent to the tip portion as in claim 6, wherein the effective blade is constituted by a main blade and a sub blade, and the tip portion Because the difference between the diameter of the main blade and the diameter of the sub blade at the side end is larger than the difference between the diameter of the main blade and the diameter of the sub blade at
In the ball end mill, the number of blades simultaneously hitting the cutting surface can be reduced, and chatter of the ball end mill can be suppressed. Thereby, the processing accuracy using a ball end mill can be improved. In addition, even during the “standing wall” processing, it is not necessary to drastically reduce the feed rate and the rotation speed, and the time required for processing can be reduced. In the “flat portion” processing by the tip portion, chattering of the end mill hardly occurs even if the rotational speed is increased, and the rotational speed of the ball end mill can be easily set.

  In the ball end mill, the effective edge of the ball end mill is composed of a tip end portion and a side end portion provided subsequent to the tip end portion, thereby improving the cutting efficiency of the ball end mill and reducing the cutting resistance at the tip end portion. However, chatter of the ball end mill is suppressed at the side end.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a front view of the ball end mill, and FIG. 2 is a side view of the same.
The ball end mill 1 is provided with a cutting blade from the tip of a columnar body having a hemispherical tip, and a shank is formed on the rear end side. In the blade configured in the ball end mill 1, a portion used for cutting is an effective blade.
The effective blade of the ball end mill 1 is constituted by cutting blades provided at the tip portion 10 and the side end portion 11, the ball blade 4 at the tip portion 10, and the main blade 3 and the auxiliary blade 3 at the side end portion 11. Is provided.
The ball blade 4 is constituted by a hemispherical tip, and extends from the tip of the ball end mill 1 to the outer peripheral surface while twisting in a certain direction. In this embodiment, the ball blade 4 is provided with four ball blades 4, 4. The ball blades 4, 4... Are connected to the blades formed on the side end portions 11, and are continuously connected to the main blade 2 or the sub blade 3.

The main blade 2 and the auxiliary blade 3 are formed in a spiral shape at the side of the ball end mill 1. In the side end portion 11, the main blade 2 and the sub blade 3 are alternately arranged, and the main blade 2 is located at a position opposed to the main blade 2 around the axis in a front view. Is provided with a secondary blade 3. And the diameter of the subblade 3 is comprised smaller than the diameter of the main blade 2, and the main blade 2 is comprised in the position away from the shaft center rather than the subblade 3. FIG. Since the main blade 2 is located outside the sub blade 3 and the ball end mill 1 moves while rotating, cutting is performed by the main blade 2 and the sub blade 3. In the cutting by the side end portion 11, the main blade 2 mainly performs cutting, and the sub-blade 3 has a diameter that is ineffective as a cutting blade. Thereby, chattering suppression of the ball end mill can be performed.
That is, a plurality of cutting blades are configured on the side portion of the ball end mill 1 and a diameter of a part of the cutting blades formed on the side portion is configured to be smaller than the diameters of the other cutting blades. This suppresses the occurrence of chatter at the side end portion 11. In the side end portion 11, the number of cutting blades reaching the diameter of the ball end mill is configured to be smaller than the number of blades at the tip end portion, thereby suppressing chattering at the side end portion 11.

In this way, by configuring the ball end mill 1, the number of blades at the tip end portion is made larger than the number of blades at the side end portion. By configuring the number of blades for cutting the workpiece to be larger at the tip than at the side end, the occurrence of chatter at the side end 11 can be suppressed while maintaining the machinability at the tip 10. . Thereby, chattering of the ball end mill 1 can be suppressed, and curved surface shape processing in which “standing wall” and “flat portion” are mixed can be easily performed.
The cutting performance is maintained by reducing the number of blades at the side portion where a plurality of blades easily hit the workpiece, and reducing the number of blades at the end portion where the peripheral speed is reduced. Thereby, chattering at the time of “standing wall” processing is suppressed, and efficient processing in “flat portion” processing can be performed.

Such a ball end mill can be easily manufactured using a conventional ball end mill. FIG. 3 is a view showing the manufacturing configuration of the ball end mill, FIG. 3 (a) is a front view showing the manufacturing configuration of the ball end mill, and FIG. 3 (b) is a side view of the same.
The ball end mill shown in the embodiment can be manufactured by reducing some of the blades from among the plurality of blades formed at the side end in the conventional ball end mill. As shown in FIG. 3, in the ball end mill, the blade at the tip portion 10 is left and two opposing blades are machined smaller than the other blades by cutting or the like among the four blades formed at the side edge portion. It is. That is, the secondary blade 3 can be configured by cutting the portion indicated by the black arrow in FIG. 3 and reducing the diameter, and the remaining blade becomes the main blade 2.
As a result, a ball end mill can be easily configured that has fewer blades at the side ends than the number of blades at the tip than the conventional ball end mill. Since the structure can be easily manufactured from the conventional ball end mill, the manufacturing cost can be reduced, and the conventional ball end mill can be manufactured as needed.

Next, the division between the front end and the side end will be described with reference to the drawings.
FIG. 4 is a diagram illustrating an example in which the tip portion is divided from the side end portion along the extending direction.

First, the structure which divides a front-end | tip part and a side end part along an axial center direction is demonstrated. In this configuration, as shown in FIG. 4, the section “a” from the tip is the tip, and the section “b” continuing to the base end side (right side in FIG. 4) after the tip is the side end. Make adjustments. It can be said that the section b is a portion of the effective blade excluding the section a.
The number of blades provided in the section b is less than the number of blades provided in the section a. As a configuration for reducing the number of blades in the section b, the number of blades acting as cutting blades in the section b is made smaller than the number of blades acting as cutting blades in the section a, and the remaining blades act as cutting blades. It is smaller than the blade.
In the connection part between the section a and the section b, a part of the blade provided in the section a can be stepped and the diameter can be rapidly reduced, or the blade diameter can be gradually reduced. It is.
In addition, the division | segmentation of a front-end | tip part and a side end part is suitably set in consideration of the material to process, speed, finishing quality, etc., In this Example, the area a is determined.
By configuring the ball end mill in this way, the number of blades that simultaneously strike the cutting surface at the side end of the ball end mill can be reduced, and chattering of the ball end mill can be suppressed. Thereby, the processing accuracy using a ball end mill can be improved. In addition, it is not necessary to extremely reduce the feed rate and the number of rotations even during “standing wall” processing, and the time required for processing can be reduced. In the “flat portion” processing by the tip portion, chattering of the end mill hardly occurs even if the rotational speed is increased, and the rotational speed of the ball end mill can be easily set.

Next, the number of blades is adjusted by dividing the tip portion from the side end portion by the peripheral speed of the blade.
FIG. 5 is a diagram showing an example of dividing the tip portion from the side end portion by the peripheral speed, and FIG. 5A is a diagram showing an example of dividing the tip portion from the side end portion by the peripheral speed, FIG. 5B is a diagram illustrating a configuration in which a step is provided in the section, and FIG. 5C is a diagram illustrating a configuration in which the auxiliary blade is gradually made smaller than the section.
The number of cutting blades is adjusted according to the peripheral side of the cutting tool blade. A portion below a certain peripheral speed is defined as a tip portion, a portion having a larger peripheral speed is defined as a side end portion, and the number of blades at the tip portion is made larger than the number of blades at the side end portion.
As shown in FIG. 5, the end mill has a configuration in which a cylindrical portion is connected to a substantially hemispherical portion, and the diameter increases toward the rear end side from the tip in the hemispherical portion, and the diameter is constant in the cylindrical portion. Become. For this reason, the peripheral speed at the time of rotation increases as it goes to the rear end side in the hemispherical part, and the peripheral speed becomes constant in the cylindrical part.
When the tip portion and the side end portion are divided by the peripheral speed, the boundary between the tip portion and the side end portion is divided into a hemispherical portion in the middle as shown by a two-dot chain line in FIG. Become.
That is, in the effective blade configured in the end mill, a portion where the peripheral speed Va is smaller than the peripheral peripheral speed Vc is a tip portion, and a portion where the peripheral speed Vb is higher than the peripheral speed Vc is a side end portion. .

As shown in FIG. 5 (b), a blade that is configured only at the tip is provided as a configuration for reducing the number of blades after the section. It is something that will not continue. Thereby, after a division, there is no sub blade, it becomes only a main blade, and chatter in a standing wall can be controlled.
Further, as shown in FIG. 5 (c), it is possible to gradually reduce some of the blades formed on the side end after the section. When the blade whose size is maintained is the main blade 2 and the small blade is the sub blade 3, the sub blade 3 is configured to be gradually smaller than the main blade 2 after the section. Thereby, the blade effective for cutting can be gradually changed in the vicinity of the section. Further, the processing accuracy using the ball end mill can be improved, and the time required for processing can be reduced without having to extremely reduce the feed rate and the rotational speed even during the “standing wall” processing. In the “flat portion” processing by the tip portion, chattering of the end mill hardly occurs even if the rotational speed is increased, and the rotational speed of the ball end mill can be easily set.

Next, the tip portion is divided from the side end portion according to the angle formed by the tangent line with the rotation axis, and the number of blades is adjusted.
FIG. 6 is a diagram illustrating an example in which the tip portion is divided from the side end portion by an angle formed between the tangent and the axis.
As shown in FIG. 6, the portion where the angle formed between the rotation axis and the tangent is larger than the constant angle α is the tip, and the portion where the angle formed between the rotation axis and the tangent is an angle β smaller than α is the side end. It is. Then, the number of blades at the front end is configured to be larger than the number of blades at the side end.
Since the number of blades is adjusted by dividing the tip end and the side end by the angle formed between the rotation axis and the tangent, the processing accuracy using a ball end mill can be improved. In addition, even during the “standing wall” processing, it is not necessary to drastically reduce the feed rate and the rotation speed, and the time required for processing can be reduced. In the “flat portion” processing by the tip portion, chattering of the end mill hardly occurs even if the rotational speed is increased, and the rotational speed of the ball end mill can be easily set.

  Also in this embodiment, as described above, a blade configured only at the tip is provided as a configuration for reducing the number of blades after the section, and this blade is provided with a step at the section and connected to the side end. It is also possible to take a method of avoiding or a method of gradually reducing some blades formed on the side end portions after the section.

Next, by gradually increasing the difference between the diameter of the main blade 2 and the diameter of the sub-blade 3 from the tip, the number of blades effective for cutting at the side edge is less than the number of blades effective for cutting at the tip. (The blade portion that works effectively can be reduced).
FIG. 7 is a schematic diagram showing a configuration in which the auxiliary blade is gradually made smaller than the tip.
The main blade 2 and the sub blade 3 are constituted by a tip P of the end mill. And the main blade 2 and the subblade 3 were comprised so that the difference of the diameter of the main blade 2 and the diameter of the subblade 3 might become large as it went to the rear end side from the front-end | tip P. As shown in FIG.
As shown in FIG. 7, the auxiliary blade 3 is configured to be smaller than the main blade 2 as it reaches the rear end position. As a result, the number of blades effective for cutting decreases from the front end P toward the rear end side, the number of effective blades for cutting is increased at the front end portion, and the number of blades effective for cutting is reduced at the side end portion. It can be done.
In this way, by configuring the end mill, cutting resistance can be reduced at the end portion of the end mill, and chattering can be suppressed at the side end portion.

The front view of a ball end mill. Similarly side view. The figure which shows the manufacture structure of a ball end mill. The figure which shows the example which divides a front-end | tip part from a side edge part along the extension direction. The figure which shows the example which divides a front-end | tip part from a side edge part by peripheral speed. The figure which shows the example which divides a front-end | tip part into a side-end part by the angle which a tangent and an axial center make. The schematic diagram which shows the structure which makes a sub blade small gradually from the front-end | tip.

Explanation of symbols

1 Ball End Mill 2 Main Blade 3 Sub Blade 4 Ball Blade 10 Tip 11 Side End

Claims (6)

  A ball end mill comprising a plurality of blades as a tip portion and a side end portion provided following the tip portion, wherein a part of the blade is configured to be small at the side end portion, and the number of blades at the tip portion is set to the side end portion. The ball end mill is characterized by having more than the number of blades. A ball end mill comprising an effective blade as a tip and a side end provided following the tip, wherein the effective blade is composed of a main blade and a sub blade having a smaller diameter than the main blade;
A ball end mill characterized in that the number of main blades provided at the tip end portion is larger than the number of main blades provided at the side end portions.   The ball end mill according to claim 1 or 2, wherein a portion from the tip of the effective blade to a certain distance in the axial center direction is a tip portion, and a portion after the tip portion of the effective blade is a side end portion.   3. The ball according to claim 1, wherein in the effective blade, a portion where the peripheral speed of the blade is equal to or less than a predetermined value is a tip portion, and a portion where the peripheral speed of the blade is faster than the predetermined value is a side end portion. End mill.   In the side view of the effective blade, the portion where the angle between the axis and the blade tangent is a certain value or more is the tip, and the portion where the angle between the axis and the blade tangent is less than the certain value is the side edge. The ball end mill according to claim 1 or 2. A ball end mill comprising an effective blade by a tip and a side end provided following the tip, wherein the effective blade is constituted by a main blade and a sub blade, and the diameter of the main blade at the tip and the sub blade A ball end mill characterized in that the difference between the diameter of the main blade and the diameter of the sub-blade at the side end portion is larger than the difference between the diameter and the diameter of the blade.

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