JPH04159009A - Ball end mill - Google Patents
Ball end millInfo
- Publication number
- JPH04159009A JPH04159009A JP2280109A JP28010990A JPH04159009A JP H04159009 A JPH04159009 A JP H04159009A JP 2280109 A JP2280109 A JP 2280109A JP 28010990 A JP28010990 A JP 28010990A JP H04159009 A JPH04159009 A JP H04159009A
- Authority
- JP
- Japan
- Prior art keywords
- tool
- tip
- blade
- main blade
- angle
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 244000145845 chattering Species 0.000 abstract description 3
- 230000000694 effects Effects 0.000 description 10
- 230000006866 deterioration Effects 0.000 description 5
- 230000007423 decrease Effects 0.000 description 4
- 230000002411 adverse Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23C—MILLING
- B23C5/00—Milling-cutters
- B23C5/02—Milling-cutters characterised by the shape of the cutter
- B23C5/10—Shank-type cutters, i.e. with an integral shaft
- B23C5/1009—Ball nose end mills
- B23C5/1027—Ball nose end mills with one or more removable cutting inserts
- B23C5/1045—Ball nose end mills with one or more removable cutting inserts having a cutting insert, the cutting edge of which subtends substantially 90 degrees
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23C—MILLING
- B23C5/00—Milling-cutters
- B23C5/02—Milling-cutters characterised by the shape of the cutter
- B23C5/10—Shank-type cutters, i.e. with an integral shaft
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Milling Processes (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
この発明は、工具本体の先端部に略円弧状の切刃が形成
されたボールエンドミルに係り、詳しくは工具の切れ味
を過度に劣化させることなく十分な工具剛性を確保して
びびり振動を抑制できるボールエンドミルに関する。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a ball end mill in which a substantially arc-shaped cutting edge is formed at the tip of a tool body, and more specifically, the present invention relates to a ball end mill that has a substantially arcuate cutting edge formed at the tip of a tool body, and specifically relates to a ball end mill that prevents excessive deterioration of the sharpness of the tool. This invention relates to a ball end mill that can suppress chatter vibration by ensuring sufficient tool rigidity.
［従来の技術］
従来、この種のボールエンドミルとしては、例えば第１
３図及び第１４図に示すように、軸状をなす工具本体１
の先端半球部１ａに２つのポケット２、３が形成され、
これらボケ・ノト２、３の回転方向を向く壁面２ａ，３
ａに形成されたチップ取付座４、５にそれぞれ一枚づつ
合計二枚のスローアウェイチップ（以下、チ・ノブと略
称する。）６、７がボルト１５で着脱自在に装着されて
なるいわゆるスローアウェイ式ボールエンドミルが知ら
れている。[Prior Art] Conventionally, as this type of ball end mill, for example, the first
As shown in Fig. 3 and Fig. 14, the tool body 1 has a shaft shape.
Two pockets 2 and 3 are formed in the tip hemispherical part 1a,
Wall surfaces 2a, 3 facing the rotation direction of these blur notes 2, 3
A so-called throw is made up of a total of two indexable tips (hereinafter referred to as chi knobs) 6 and 7, which are removably attached with bolts 15 to tip mounting seats 4 and 5 formed in a. Away type ball end mills are known.
ここで、上記チップ６．７は、いずれも超硬合金を厚さ
一定の平板状に形成してなるもので、−方の主チップ６
のすくい面６ａと側面６ｂとの稜線部には略１／４円弧
状の円弧刃８とこの円弧刃８の後端に連続する直線刃９
とからなる主刃１０がチップ中心に対して対称に形成さ
れている。さらに、上記主チップ６の円弧刃８の先端部
には着座面６ｃに向かって凸曲線を描きつつ延びる湾曲
部８ａが形成されている。一方、副チップ７は、そのす
くい面７ａと側面７ｂとの稜線部に略１／４円弧状の円
弧刃１１とこの円弧刃１１の後端に連続する直線刃１２
とからなる副刃１３が形成される点で上記主チンプロと
ほぼ同様の構成を有するものの、円弧刃１１の先端側に
直線刃１２と直交する方向に延びる切欠面１４が形成さ
れる点で主チップ６と異なっている。Here, the chips 6 and 7 are each made of cemented carbide formed into a flat plate shape with a constant thickness, and the main chip 6 on the negative side
At the ridgeline between the rake face 6a and the side surface 6b, there is a circular arc blade 8 having a substantially 1/4 arc shape and a straight blade 9 continuous to the rear end of the circular arc blade 8.
A main blade 10 consisting of is formed symmetrically with respect to the center of the chip. Furthermore, a curved portion 8a extending in a convex curve toward the seating surface 6c is formed at the tip of the arcuate blade 8 of the main tip 6. On the other hand, the sub-chip 7 has an approximately 1/4 arc-shaped arcuate blade 11 on the ridgeline between the rake face 7a and the side surface 7b, and a straight-line blade 12 continuous to the rear end of the arcuate blade 11.
Although it has almost the same configuration as the main chimpano in that a secondary blade 13 consisting of It is different from chip 6.
そして、第１５図ないし第１７図に示すように上記各チ
ップ６．７は、主チップ６の主刃１０の先端が工具軸線
方向からの底面視において工具回転中心Ｐ０に一致し、
他方、副チｙブ７の副刃１３の先端が回転中心Ｐ０から
後退するようにそれぞれ位置決めされ、ボルト１５で締
め付けられて工具本体１に着脱自在に装着される。この
際、各月１０．１３の７キシヤルレーキ角γいはいずれ
も正角に設定され、このため第１７図に示すように、主
刃１０および副刃１３はともに工具軸線方向からの底面
視においてチップ着座面６Ｃ１７Ｃ側に中心Ｐ１、Ｐ、
を有する円弧を描くこととなる。As shown in FIGS. 15 to 17, in each of the chips 6.7, the tip of the main blade 10 of the main chip 6 coincides with the tool rotation center P0 when viewed from the bottom from the tool axis direction,
On the other hand, the tips of the auxiliary blades 13 of the auxiliary tube 7 are positioned so as to retreat from the center of rotation P0, and are tightened with bolts 15 and detachably attached to the tool body 1. At this time, the 7-axis rake angle γ of each month 10.13 is set to a right angle, and therefore, as shown in FIG. 17, both the main blade 10 and the secondary blade 13 are Centers P1, P, on the chip seating surface 6C17C side.
This will draw an arc with .
［発明が解決しようとする課題］
ところで、上述した従来のボールエンドミルにオイテは
、主刃１０及び副刃１３のアキシャルレーキ角γいをい
ずれも正角に設定しているので、チップポケット２．３
の回転方向を向く壁面２ａ、３ａやチップ取付座４．５
の底面４ａ、５ａを工具後端側に向かうほど漸次工具回
転方向と反対側へ傾斜する傾斜面状に形成する必要があ
る。このためチ・ノブポケット２．３の背後の工具本体
１の肉厚ｔ （第１５図参照）が工具後端側に向かうに
従って徐々に減少し、これに伴って工具剛性が劣化して
びびり振動を招く等の弊害が生じ、時として、特に切削
荷重が大きい主刃１０の側で工具折損が生じることさえ
あった。[Problems to be Solved by the Invention] By the way, in the conventional ball end mill described above, the axial rake angles γ of the main blade 10 and the secondary blade 13 are both set to a right angle, so that the chip pocket 2. 3
Wall surfaces 2a and 3a facing the rotation direction of the chip mounting seat 4.5
It is necessary to form the bottom surfaces 4a and 5a in the shape of an inclined surface that gradually slopes toward the opposite side of the tool rotation direction toward the rear end of the tool. For this reason, the wall thickness t (see Fig. 15) of the tool body 1 behind the chi-knob pocket 2.3 gradually decreases toward the rear end of the tool, and as a result, the tool rigidity deteriorates and chatter vibration occurs. In some cases, the tool may even break on the side of the main blade 10 where the cutting load is particularly large.
このような欠点を解消するには、主刃１０及び副刃１３
のアキシャルレーキ角γ、をともに負角としてチップポ
ケット２．３の背後の肉厚ｔを増加させれば良いが、か
かる場合には主刃１０及び副刃１３に加わる切削抵抗が
共に増大して工具の切れ味が劣化し、切削時の所要動力
の増加や切刃欠損の発生頻度の増加等の弊害を招くこと
となる。In order to eliminate such defects, the main blade 10 and the secondary blade 13
The wall thickness t behind the chip pocket 2.3 can be increased by setting the axial rake angle γ of The sharpness of the tool deteriorates, leading to adverse effects such as an increase in the power required during cutting and an increase in the frequency of occurrence of cutting edge breakage.
この発明は、このような背景の下になされたもので、工
具の切れ味を過度に劣化させることなく、一定の工具剛
性を確保して工具のびびり振動を効果的に抑制できるボ
ールエンドミルを提供することを目的とする。This invention was made against this background, and provides a ball end mill that can ensure a certain level of tool rigidity and effectively suppress tool chatter vibration without excessively deteriorating the sharpness of the tool. The purpose is to
［課題を解決するための手段］
上記課題を解決するためにこの発明のボールエンドミル
は、主刃のアキシャルレーキ角を負角に、上記副刃のア
キシャルレーキ角を正角に設定したものである。[Means for Solving the Problems] In order to solve the above problems, the ball end mill of the present invention is such that the axial rake angle of the main blade is set to a negative angle, and the axial rake angle of the secondary blade is set to a positive angle. .
この場合、主刃の切れ味を一層向上させるには主刃のす
くい面にブレーカ溝を形成することが好ましく、さらに
はブレーカ溝の溝幅あるいは溝深さを主刃の先端から後
端側へ向かうに従って漸次増大させ、あるいは溝幅及び
溝深さをともに主刃先端側から後端側へ向かうに従って
増大させることが好適である。In this case, in order to further improve the sharpness of the main blade, it is preferable to form a breaker groove on the rake face of the main blade, and furthermore, the groove width or groove depth of the breaker groove should be adjusted from the tip of the main blade toward the rear end. It is preferable that the groove width and the groove depth are both increased gradually from the leading end of the main blade toward the rear end.
［作用〕
上記構成によれば、切削時により大きな切削荷重が加わ
る主刃のアキシャルレーキ角が負角に設定されているの
で、これに応じて主刃側のチップポケットが工具軸方向
後端側へ向かうに従って漸次工具回転方向側へ傾斜する
こととなる。従って、特に剛性を必要とする主刃用のチ
シブポケソト背後の肉厚が工具後端側で増大して十分な
剛性が確保される。この場合、アキシャルレーキ角を負
角に設定したことによって主刃の切削抵抗が多少増加す
るものの、工具剛性の増加の程度がこれを上回るので、
びびり振動がかえって増加する等の弊害が生じるおそれ
はない。[Function] According to the above configuration, the axial rake angle of the main blade to which a larger cutting load is applied during cutting is set to a negative angle, so the chip pocket on the main blade side is moved toward the rear end in the tool axis direction accordingly. As it goes toward the direction of the tool, it gradually becomes inclined toward the tool rotation direction. Therefore, the wall thickness behind the main cutting edge, which requires particularly rigidity, increases on the rear end side of the tool, thereby ensuring sufficient rigidity. In this case, although the cutting resistance of the main blade increases somewhat by setting the axial rake angle to a negative angle, the degree of increase in tool rigidity exceeds this, so
There is no risk of adverse effects such as an increase in chatter vibration.
一方、副刃側のアキシャルレーキ角は従来通り正角に設
定されているので切削抵抗が小さ（、この結果、工具の
切れ味の低下も最小限度に止どめられる。さらに、副刃
側に加わる切削荷重は主刃側に比較して遥かに小さいの
で、副刃のアキシャルレーキ角を正角としても工具剛性
が不足することはない。On the other hand, since the axial rake angle on the secondary edge side is set to a regular angle as before, the cutting resistance is small (as a result, the deterioration of the tool's sharpness is kept to a minimum. Since the cutting load is much smaller than that on the main cutting edge side, tool rigidity will not be insufficient even if the axial rake angle of the secondary cutting edge is set to a regular angle.
さらに、主刃のアキシャルレーキ角が負角となるため、
主刃の工具軸線方向からの底面視においては主刃の後端
側が先端側よりも工具回転方向側へ突出し、これにより
主刃はその後端側から漸次被削材に切り込まれる。他方
、副刃はアキシャルレーキ角が正角であるために、上記
底面視において副刃はその後端側か先端側よりも工具回
転方向と反対側へ後退し、これにより副刃はその先端側
から漸次被削材に切り込まれる。このため、主刃及び副
刃から伝達される振動が互いに打ち消し合う方向に作用
し、びびり振動の成長が阻止される。Furthermore, since the axial rake angle of the main blade is a negative angle,
When viewed from the bottom of the main blade in the tool axis direction, the rear end side of the main blade protrudes more toward the tool rotation direction than the tip side, so that the main blade gradually cuts into the workpiece from the rear end side. On the other hand, since the axial rake angle of the secondary blade is a positive angle, the secondary blade retreats toward the opposite side of the tool rotation direction from the rear end side or the tip side in the above bottom view. Gradually cuts into the work material. Therefore, the vibrations transmitted from the main blade and the secondary blade act in a direction that cancels each other out, and the growth of chatter vibration is prevented.
また、主刃のすくい面にブレーカ溝を形成した場合には
、主刃の法線方向の断面視におけるすくい角が正角方向
へ変化するので、その分切れ味が向上する。Further, when a breaker groove is formed on the rake face of the main blade, the rake angle in a cross-sectional view in the normal direction of the main blade changes in the positive direction, so that the cutting quality is improved accordingly.
加えて、円弧状をなす主刃から生成される切屑は主刃の
先端側で薄く後端側で厚く変化するため、ブレーカ溝の
溝幅や溝深さを変化させた場合には切屑の厚さに応じて
必要最小限のブレーカ溝を確保でき、工具剛性の低下を
最小限に止どめつつ主刃の切れ味や切屑排出性を向上さ
せることができる。In addition, the chips generated from the arc-shaped main blade are thinner at the leading edge and thicker at the rear end, so if you change the groove width or depth of the breaker groove, the chip thickness The required minimum breaker groove can be secured according to the cutting conditions, and the sharpness of the main blade and chip evacuation can be improved while minimizing the decrease in tool rigidity.
［実施例］
以下、第１図ないし第５図を参照して、本発明の一実施
例を説明する。[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.
本実施例のボールエンドミルは主刃のアキシャルレーキ
角にその特徴を有するものであるが、その説明に先立っ
て第２図ないし第４図を参照してポールエンドミルの全
体構成を説明する。なお、上述した従来例と同一の構成
要素には同一符号を付し、その説明を省略する。The ball end mill of this embodiment is characterized by the axial rake angle of the main blade, but prior to explaining this, the overall structure of the pole end mill will be explained with reference to FIGS. 2 to 4. Note that the same components as those in the conventional example described above are given the same reference numerals, and their explanations will be omitted.
第２図及び第３図において符号２０は工具本体である。In FIGS. 2 and 3, reference numeral 20 indicates a tool body.
この工具本体２０の先端部には略半球状をなす球状部２
１が形成され、この球状部２１には、当該球状部２１の
外周をほぼ１７４周切り欠いてなる２つのチップポケッ
ト２２．２３が形成されている。そして、これらチップ
ポケット２２．２３の回転方向を向く壁面にはチップ取
付座２４．２５が形成され、これらチップ取付座２４．
２５に主チップ６、副チップ７が載置されてボルト１５
で着脱自在に取り付けられている。A spherical portion 2 having a substantially hemispherical shape is provided at the tip of the tool body 20.
1 is formed, and two chip pockets 22 and 23 are formed in this spherical portion 21 by cutting approximately 174 times around the outer circumference of the spherical portion 21. Chip mounting seats 24.25 are formed on the wall surfaces of these chip pockets 22.23 facing the rotational direction.
The main chip 6 and the sub chip 7 are placed on the bolt 15.
It is attached removably.
ここで、第３図及び第４図に示すように、上記チップ６
．７のうち、主チップ６は、その主刃１０の先端が工具
軸線方向からの底面視において工具回転中心Ｐ０と一致
するように位置決めされており、他方、副チップ７は、
その副刃１３の先端が回転中心Ｐ０から工具外周側へ後
退するように位置決めされている。Here, as shown in FIGS. 3 and 4, the chip 6
．． 7, the main tip 6 is positioned so that the tip of its main blade 10 coincides with the tool rotation center P0 when viewed from the bottom from the tool axis direction, while the sub-tip 7 is
The tip of the auxiliary blade 13 is positioned so as to retreat toward the outer circumferential side of the tool from the rotation center P0.
そして、第１図に示すように、主チップ６が装着される
第１のチップ取付座２４の底面２４ａは工具軸方向先端
側から後端側へ向かうほど漸次工具回転方向側へ傾斜す
る傾斜面に形成され、これにより主刃１０の７キシヤル
レーキ角γ□は負角に設定されている。このため、第４
図に示すように、工具軸線方向からの底面視における主
刃１０は、円弧刃８の湾曲部８ａが工具回転中心Ｐ０か
ら工具外周側へ離間するに従って工具回転方向側べ突出
する円弧を描くものの、円弧刃８の残る部分から直線刃
９の後端にかけての部分がチップ６のすくい面６ａ側に
中心Ｐ、を有する円弧を描いて直線刃９の後端が最も工
具回転方向へ突出し、チップ着座面６ｃ側に中心Ｐ、を
有する円弧を描（従来例（第１７図参照）と著しく異な
っている。As shown in FIG. 1, the bottom surface 24a of the first tip mounting seat 24, on which the main tip 6 is attached, is an inclined surface that gradually slopes in the tool rotation direction as it goes from the tip side in the tool axis direction to the rear end side. As a result, the 7-axis rake angle γ□ of the main blade 10 is set to a negative angle. For this reason, the fourth
As shown in the figure, the main blade 10 when viewed from the bottom from the tool axis direction draws a circular arc that protrudes from the side in the tool rotation direction as the curved portion 8a of the arc blade 8 moves away from the tool rotation center P0 toward the tool outer circumference. , the part from the remaining part of the arcuate blade 8 to the rear end of the straight blade 9 draws an arc having a center P on the rake surface 6a side of the chip 6, and the rear end of the straight blade 9 protrudes the most in the tool rotation direction, and the chip A circular arc having a center P is drawn on the side of the seating surface 6c (this is significantly different from the conventional example (see FIG. 17)).
一方、第５図に示すように、副チップ７が装着される第
２のチップ取付座２５の底面２５ａは工具軸方向先端側
から後端側へ向かうほど漸次工具回転方向と反対側へ傾
斜する傾斜面に形成され、これにより副刃１３のアキシ
ャルレーキ角γ。は従来通り正角に設定されている。従
って、工具軸線方向からの底面視における副刃１３は、
従来と同様にチップ着座面７ｃ側に中心Ｐ、を有する円
弧を描いている。On the other hand, as shown in FIG. 5, the bottom surface 25a of the second tip mounting seat 25, on which the sub-tip 7 is attached, gradually slopes in the direction opposite to the tool rotation direction as it goes from the leading end to the rear end in the tool axis direction. The axial rake angle γ of the secondary cutting edge 13 is formed on an inclined surface. is set to a regular angle as before. Therefore, the sub-edge 13 in the bottom view from the tool axis direction is
As in the conventional case, a circular arc having a center P is drawn on the chip seating surface 7c side.
ここで、上記各月１０．１３のアキシャルレーキ角γ、
１、γ。は工具径や被削材の材質等に応じて適宜変更さ
れるものであるが、なるべくは、主刃１０のアキシャル
レーキ角γＡｌを一５°〜−１゜の範囲に、副刃１３の
７キシヤルレーキ角γ。を１°〜１０°に設定すること
が好ましい。主刃１０のアキシャルレーキ角γえ、が−
１″より正角側に偏った場合、又は副刃１３の７キシヤ
ルレーキ角γ□が１°に満たない場合には、これらアキ
シャルレーキ角γＡ１、γ。を正負で変化させることを
特徴とする本願発明の効果を十分に発揮できないおそれ
があり、また、主刃１０のアキシャルレーキ角γ４．が
一５°よりも負角側に偏った場合には切削抵抗の増加の
程度が大きくなって工具の切れ味が著しく劣化するおそ
れがあり、さらに副刃１３のアキシャルレーキ角γ□が
１０°を越えた場合には、副刃用チップポケット２３の
背後の肉厚ｔ、が過度に減少して工具剛性が不足するお
それが生じるからである。ちなみに、図示の例では工ｊ
Ｌ 径２５ ｓ＋ｍに対して主刃１０のアキンヤルレー
キ角γ６．が一２″、副刃１３のアキシャルレーキ角γ
□が５°に設定されている。Here, the axial rake angle γ of 10.13 for each month above,
1, γ. Although it is possible to change the axial rake angle γAl of the main cutting edge 10 in the range of -5° to -1°, it is preferable to set the axial rake angle γAl of the main cutting edge 10 in the range of -1° to 7° of the secondary cutting edge 13. Axial rake angle γ. is preferably set to 1° to 10°. The axial rake angle γ of the main blade 10 is -
If the axial rake angle γ□ of the sub-cutting blade 13 is less than 1°, the axial rake angles γA1, γ are changed between positive and negative. There is a risk that the effects of the invention may not be fully exerted, and if the axial rake angle γ4 of the main blade 10 is biased toward the negative angle side from 15 degrees, the degree of increase in cutting force will be large and the tool will become damaged. There is a risk that the sharpness will deteriorate significantly, and if the axial rake angle γ□ of the sub-edge 13 exceeds 10°, the wall thickness t behind the sub-edge chip pocket 23 will be excessively reduced, resulting in poor tool rigidity. This is because there is a risk that there will be a shortage of
Achinyal rake angle γ6 of main blade 10 for L diameter 25 s+m. 12", the axial rake angle γ of the sub-edge 13
□ is set to 5°.
しかして、以上のように構成されたボールエンドミルに
おいては、主刃１０のアキシャルレーキ角γ。を負角に
設定しているので、主刃用チップポケット２２の回転方
向を向く壁面２２ａや第１のチップ取付座２４の底面２
４ａがいずれも工具後端側へ向かうに従って漸次工具回
転方向側へ傾斜する。従って、チップポケット２２の背
後の肉厚ｔ、が従来に比して大幅に増大し、この結果工
具剛性が向上してびびり振動や工具折損の発生が抑制さ
れる。この場合、主刃１０のアキシャルレーキ角γ□が
負角となるために主刃１０に加わる切削荷重が増加して
かえってびびり振動を招来することも考えられなくはな
いが、実際には工具剛性の増加の程度が切削荷重の増加
の程度を遥かに上回るので、びびり振動の増大等を招く
おそれはない。Therefore, in the ball end mill configured as described above, the axial rake angle γ of the main blade 10. is set to a negative angle, so that the wall surface 22a facing the rotation direction of the main blade chip pocket 22 and the bottom surface 2 of the first chip mounting seat 24
4a are all gradually inclined toward the tool rotation direction as they move toward the rear end of the tool. Therefore, the wall thickness t behind the chip pocket 22 is significantly increased compared to the conventional case, and as a result, tool rigidity is improved and occurrence of chatter vibration and tool breakage is suppressed. In this case, since the axial rake angle γ□ of the main blade 10 becomes a negative angle, it is possible that the cutting load applied to the main blade 10 increases and causes chatter vibration, but in reality, the tool rigidity Since the degree of increase in is far greater than the degree of increase in cutting load, there is no risk of an increase in chatter vibration or the like.
他方、副刃１３のアキンヤルレーキ角γい、は従来通り
正角に設定されているので、副刃１３のアキシャルレー
キ角γ□をも負角に設定した場合に比して工具全体の切
れ味は遥かに良好に保たれる。On the other hand, since the axial rake angle γ of the sub-edge 13 is set to a positive angle as before, the sharpness of the entire tool is much greater than when the axial rake angle γ□ of the sub-edge 13 is also set to a negative angle. kept in good condition.
また、副刃用チップポケット２３の背後の肉厚ｔ。Also, the wall thickness t behind the sub-blade chip pocket 23.
が工具後端側へ向かうほど減少するものの、副刃１３に
加わる切削荷重は主刃１０に比して遥かに小さいので工
具剛性に与える影響は小さく、従って工具全体としては
十分な剛性が確保される。Although the cutting load decreases toward the rear end of the tool, the cutting load applied to the secondary edge 13 is much smaller than that to the main edge 10, so the effect on tool rigidity is small, and therefore sufficient rigidity is ensured for the tool as a whole. Ru.
また、本実施例のボールエンドミルにおいては、主刃１
０及び副刃１３が被削材（図示せず）に切り込まれる際
において、主刃１０はその皐線刃９の後端側が円弧刃８
の先端側よりも工具回転方向に突出していることから直
線刃９側から円弧刃８の先端側へ向かって徐々に切り込
まれてゆき、他方、副刃１３は直線刃１２側が工具回転
方向ζ反対側へ後退するので逆に円弧刃１１側から直線
刃１２の後端側へと徐々に切り込まれてゆく。従９て、
主刃ｌＯ及び副刃１３から入力される振動が互いに打ち
消し合う方向に作用し、この結果、びびり振動の成長が
抑制されるという効果も得られる。ちなみに、従来例で
は主刃ｌＯ及び副刃１３が共に円弧刃８．１１から直線
刃９．１２側へと切り込まれてゆくため、各月１０．１
３から伝達される振動の方向が一致し易く、その分びび
り振動も大きく成長することになる。In addition, in the ball end mill of this embodiment, the main blade 1
0 and the sub-edge 13 cut into the workpiece (not shown), the main edge 10 has its creased edge 9 on its rear end side as the arc edge 8.
Because it protrudes in the tool rotation direction beyond the tip side of the blade, the cut is gradually made from the straight edge 9 side toward the tip side of the circular arc blade 8. On the other hand, the auxiliary edge 13 has its straight edge 12 side protruded in the tool rotation direction ζ. Since it retreats to the opposite side, it gradually cuts from the arcuate blade 11 side to the rear end side of the straight blade 12. 9th,
The vibrations input from the main blade 1O and the secondary blade 13 act in a direction that cancels each other out, and as a result, the effect of suppressing the growth of chatter vibration is also obtained. By the way, in the conventional example, both the main blade lO and the secondary blade 13 are cut from the circular blade 8.11 to the straight blade 9.12 side, so each month 10.1
The directions of the vibrations transmitted from 3 are likely to match, and the chatter vibration will grow accordingly.
なお、上記実施例では特にチップ６．７のすくい面６ａ
、７ａがいずれも平面状に形成されている場合について
説明したが、本発明はこれにｌｌａルものでなく、例え
ば第６図ないし第８図に示すように、主チップ６のすく
い面６ａに、主刃１０に沿って微小間隔（以下、ランド
幅と称する。）ｄを保ちつつ延びる溝幅Ｗのブレーカ溝
３０を形成しても良い。この場合には、ブレーカ溝３０
によって主刃１０の一法線方向の断面視におけるすくい
角（以下、チップすくい角と称する。）γ３が正角とな
るまため、主刃１０の切れ味が向上するとともに切屑排
出性が向上して切削抵抗が一層減少するという効果があ
る。なお上記ランド幅ｄについては工具径等に応じて適
宜変更して良いが、０，０１〜０．５−一の範囲が好適
に用いられる。In addition, in the above embodiment, in particular, the rake face 6a of the chip 6.7
, 7a are all formed in a planar shape, but the present invention is not limited to this. For example, as shown in FIGS. 6 to 8, the rake face 6a of the main chip 6 is , a breaker groove 30 having a groove width W may be formed extending along the main blade 10 while maintaining a minute interval (hereinafter referred to as land width) d. In this case, the breaker groove 30
Therefore, the rake angle (hereinafter referred to as the chip rake angle) γ3 in a cross-sectional view in one normal direction of the main blade 10 becomes a regular angle, so that the sharpness of the main blade 10 is improved and the chip evacuation performance is improved. This has the effect of further reducing cutting resistance. Note that the land width d may be changed as appropriate depending on the tool diameter, etc., but a range of 0.01 to 0.5-1 is preferably used.
ここで、上記実施竺のボールエンドミルのように円弧状
の主刃１０を有するものにおいては、主刃】０の被削材
（図示略）に対する径方向の切込量が、円弧刃８の先端
側で小さく、後端側すなわち直線刃９に連なる側で大き
くなることから、主刃ＸＯから生成される切屑も主刃ｌ
Ｏの先端で薄く、後端側で厚くなる。従って、上記のよ
うにブレーカ溝３０を形成する場合、溝幅Ｗや溝深さｈ
を一定とすれば、主刃１０の後端側から生成される切屑
の厚さに応じて溝幅Ｗや溝深さｄを決定しなければなら
ないため、主刃１０の先端側では生成される切屑に比し
てブレーカ溝３０が大き過ぎて工具剛性を無駄に劣化さ
せるという不都合が生じる。Here, in a ball end mill having an arc-shaped main blade 10 such as the ball end mill of the above-mentioned example, the radial cutting amount into the workpiece (not shown) of the main blade 0 is the tip of the arc blade 8. Chips generated from the main blade
It is thinner at the tip of the O and thicker at the rear end. Therefore, when forming the breaker groove 30 as described above, the groove width W and the groove depth h
Assuming that is constant, the groove width W and the groove depth d must be determined according to the thickness of chips generated from the rear end side of the main blade 10. The problem arises that the breaker groove 30 is too large compared to the chips, which unnecessarily deteriorates tool rigidity.
そこで、このような場合には、第９図ないし第１２図に
示すように溝幅Ｗを刃１０の先端側から後端側へ向かう
に従って漸次増大させるとともに、溝深さｈをその底部
が工具側面視において一定の傾斜角αで傾斜するように
漸次増大させ、あるいはこれら溝幅Ｗや溝深さｈのいず
れか一方のみを上記の通り変化させることにより、ブレ
ーカ溝３０をその先端から後端に至るまで切屑に見合っ
た大きさに形成し、これにより工具剛性が過度に劣化す
るのを防止しつつ切屑排出性や切れ味の向上を図ること
ができる。Therefore, in such a case, as shown in FIGS. 9 to 12, the groove width W is gradually increased from the tip side to the rear end side of the blade 10, and the groove depth h is adjusted so that the bottom part is the tool. By gradually increasing the inclination so that it is inclined at a constant inclination angle α when viewed from the side, or by changing only either the groove width W or the groove depth h as described above, the breaker groove 30 can be moved from its tip to its rear end. By forming the tool to a size commensurate with the size of the chips, it is possible to prevent excessive deterioration of tool rigidity while improving chip evacuation and sharpness.
以上の実施例では特にチップを２枚用いるボールエンド
ミルを例に挙げて説明したが、本発明はこれに限るもの
ではなく、副チップ７を２枚あるいはそれ以上設けたも
のであっても当然に適用し得るものである。また、特に
スローアウェイ式のボールエンドミルでなくても、工具
本体１０の先端側にチップをろう付は接合した構成や工
具全体を一体に成形するソリッド式の構成であっても主
刃側のチップボケｙト背後の肉厚を増大させて工具剛性
を確保するという効果が得られる。In the above embodiments, a ball end mill that uses two chips has been specifically explained as an example, but the present invention is not limited to this, and it is of course possible to use a ball end mill that uses two or more auxiliary chips 7. It is applicable. In addition, even if it is not a throw-away type ball end mill, even if it has a configuration in which the tip is brazed or joined to the tip side of the tool body 10 or a solid type configuration in which the entire tool is integrally molded, the tip blurring on the main blade side may occur. The effect of increasing the wall thickness behind the y-toe and ensuring tool rigidity can be obtained.
（実験例）
本発明の効果を明らかにすべ（、第９図ないし第１２図
に示すボールエンドミルを実際に製造して切削試験を行
った。このとき、切削所要動力を測定して切削抵抗の大
小すなわち切れ味の良否を確認するとともに、生成され
る切屑を監視して切削排出性を判断し、さらにはびびり
振動の大小を確認すべ（切削音を監視するとともに、工
具剛性の高低をも測定した。これらの結果を表１に示す
。(Experimental example) In order to clarify the effects of the present invention, the ball end mill shown in Figs. 9 to 12 was actually manufactured and a cutting test was conducted. At this time, the required cutting power was measured and the cutting resistance was In addition to checking the size, that is, the quality of the cutting quality, it is necessary to monitor the generated chips to determine the cutting evacuation property, and also check the size of chatter vibration (in addition to monitoring the cutting noise, it is also necessary to measure the height of the tool rigidity). .These results are shown in Table 1.
なお、比較例として主刃及び副刃のアキシャルレーーキ
角を両方とも正角に設定した従来のボールエンドミルで
切削を行ったときの結果を併記する。As a comparative example, the results obtained when cutting was performed using a conventional ball end mill in which the axial rake angles of the main blade and the secondary blade were both set to a regular angle are also shown.
また、切削条件や各部の寸法は下記の通りである。Furthermore, the cutting conditions and dimensions of each part are as follows.
■切削条件
・被削材・・・・・Ｓ ＣＭ ４４０ （Ｈｍ ２２０
）・切削速度・・ １２０賞／臘ｉｎ。■Cutting conditions/work material...S CM 440 (Hm 220
)・Cutting speed... 120 awards/臘in.
・軸方向切込み量・・・・・１〇−
・切削幅・・・・・・３窮謁、６−簡の２段階・テーブ
ル送り量
・・・・切削幅３ｍ−のとき４００ ｗｒｗｈ／ ｓｉ
ｎ。・Axis depth of cut: 10- ・Cutting width: 2 stages of 3-way and 6-way ・Table feed amount: 400 wrwh/si when cutting width is 3m-
n.
切削幅６ｍ−のとき６００ ｏｖａ／ ｍｉれ。600 ova/mi when cutting width is 6m.
・−刀当たり送り量
・・ 切削幅３ｍ１−のとき０ 、１３１１１１／
ｒｅｖ。・-Feed amount per knife... 0 when cutting width is 3m1-, 131111/
rev.
切削幅６悄−のとき０ 、２０ ａｍ／ ｒｅｖ。0, 20 am/rev when cutting width is 6 mm.
■寸法
１ 本発明品
・工具シャンク径・・・・・・φ３２＋ｎｍ・主刃アキ
シャルレーキ角γ□・・・・・・−２゜・副刃アキシャ
ルレーキ角γ□・・・・・ ５ａ・ランド幅ｄ −＝
−０、１＠簡
・チップすくい角γ、・・・・・・１５゜ｉｉ、比較品
・主刃及び副刃アキシャルレーキ角γ・・・・・・５゜
・その他の寸法は本発明品と同様である。■Dimensions 1 Inventive product・Tool shank diameter・・・φ32+nm・Main blade axial rake angle γ□・・・・−2°・Sub-blade axial rake angle γ□・・・・5a・Land Width d −=
-0, 1＠Simplified・Insert rake angle γ,・・・15゜ii、Comparative product・Main and sub-edge axial rake angle γ・・・・・・5゜・Other dimensions are inventive product It is similar to
以下余白
表１
表１から明らかなように、本発明に係るボールエンドミ
ルでは切削抵抗すなわち切れ味の点で従来例とほぼ同等
の性能を示し、工具本体の剛性に関しては従来例を上回
っている。また切削時のびびり音も従来例に比して十分
に低く、かつ切屑排出性も良好で、これより本発明の優
位性が明らである。Margin Table 1 below As is clear from Table 1, the ball end mill according to the present invention exhibits almost the same performance as the conventional example in terms of cutting resistance, that is, sharpness, and exceeds the conventional example in terms of the rigidity of the tool body. Furthermore, the chattering noise during cutting is sufficiently lower than that of the conventional example, and the chip evacuation property is also good, which clearly shows the superiority of the present invention.
［発明の効果］
以上説明したように、この発明は、切削時により大きな
切削荷重が加わる主刃のアキシャルレーキ角のみを負角
に設定したものであるため、特に剛性を必要とする主刃
用のチップポケット背後の肉厚が増大し、このため、十
分な工具剛性を確保してびびり振動の発生や工具折損の
発生を抑制できるとともに、工具の切れ味の低下を最小
限に止どめることができるという優れた効果を奏する。[Effects of the Invention] As explained above, in this invention, only the axial rake angle of the main blade to which a larger cutting load is applied during cutting is set to a negative angle, so it is particularly suitable for main blades that require rigidity. The wall thickness behind the chip pocket has increased, thereby ensuring sufficient tool rigidity to suppress the occurrence of chatter vibration and tool breakage, as well as minimizing deterioration in tool sharpness. It has the excellent effect of being able to
さらに、主刃及び副刃が被削材に切り込まれる位置が変
化して主刃及び副刃から伝達される振動が互いに打ち消
し合う方向に作用するので、振動の成長が阻止されてび
びり振動による加工精度の劣化が未然に回避される。Furthermore, the positions where the main and secondary blades cut into the workpiece change, and the vibrations transmitted from the main and secondary blades act in a direction that cancels each other out, preventing the growth of vibrations and preventing chatter vibrations. Deterioration of processing accuracy is avoided.
また、特に主刃のすくい面にブレーカ溝を形成した場合
には切屑排出性や切れ味を一層向上させることができ、
さらにブレーカ溝の溝幅や溝深さを主刃の先端側から後
端側に向かって変化させた場合には、主刃で生成される
切屑の厚さに応じて必要最小限のブレーカ溝を確保して
、工具剛性の低下を最小限に止どめつつ主刃の切れ味や
切屑排出性を向上させることができる。In addition, especially when a breaker groove is formed on the rake face of the main blade, chip evacuation and sharpness can be further improved.
Furthermore, when changing the groove width and groove depth of the breaker groove from the leading edge to the rear edge of the main blade, the minimum required breaker groove can be adjusted according to the thickness of chips generated by the main blade. This makes it possible to improve the sharpness of the main blade and chip evacuation while minimizing the decrease in tool rigidity.
第１図ないし第５図は本発明の一実施例を示すもので、
第１図は主刃を工具側方から見たときの側面図、第２図
は主刃をそのすくい面と直交する方向から見たときの平
面図、第３図は第２図の■方向からの矢視図、第４図は
工具底面の拡大図、第５図は第３図の■方向からの矢視
図、第６図ないし第８図は他の実施例を示す図で、第６
図は主刃をそのすくい面と直交する方向から見たときの
平面図、第７図は第６図の■方向からの矢視図、第８図
は第６図の■−■線における断面図、
第９図ないし第１２図はさらに他の実施例を示す図で、
第９図は主刃をそのすくい面と直交する方向から見たと
きの平面図、第１０図は第９図のＸ方向からの矢視図、
第１１図は第９図のＸＩ−ＸＩ線における断面図、第１
２図は第９図の■−■線における断面図、
第１３図ないし第１７図は従来例を示す図で、第１３図
は工具の平面図、第１４図は底面図、第１５図は第１４
図のＸ■力方向らの矢視図、第１６図は第１４図のＸＶ
１方向からの矢視図、第１７図は底面の拡大図である。
６ａ・・・・・・主刃のす（い面、１０・・・・・主刃
、１３・・・・・・副刃、２０・・・・・工具本体、３
０・・・・・・ブレーカ溝、
γ□・・・・・主刃のアキシャルレーキ角、γ□・・・
・・副刃のアキシャルレーキ角、Ｐｏ・・・・・・工具
回転中心。1 to 5 show an embodiment of the present invention,
Figure 1 is a side view of the main blade when viewed from the side of the tool, Figure 2 is a plan view of the main blade viewed from the direction perpendicular to the rake face, and Figure 3 is the direction shown in Figure 2. FIG. 4 is an enlarged view of the bottom of the tool, FIG. 5 is a view taken from direction ■ in FIG. 3, and FIGS. 6 to 8 are views showing other embodiments. 6
The figure is a plan view of the main blade when viewed from the direction perpendicular to the rake face, Figure 7 is a view taken from the direction ■ in Figure 6, and Figure 8 is a cross section taken along the line ■-■ in Figure 6. 9 to 12 are diagrams showing still other embodiments,
Fig. 9 is a plan view of the main blade when viewed from a direction perpendicular to the rake face, Fig. 10 is a view taken from the X direction in Fig. 9;
Figure 11 is a sectional view taken along the line XI-XI in Figure 9;
Fig. 2 is a sectional view taken along the line ■-■ in Fig. 9, Figs. 13 to 17 are views showing conventional examples, Fig. 13 is a plan view of the tool, Fig. 14 is a bottom view, and Fig. 15 is a diagram showing a conventional example. 14th
Figure 16 shows XV in Figure 14.
FIG. 17, which is a view from one direction, is an enlarged view of the bottom surface. 6a...Main blade face, 10...Main blade, 13...Secondary blade, 20...Tool body, 3
0... Breaker groove, γ□... Axial rake angle of main blade, γ□...
...Axial rake angle of sub-edge, Po... Center of tool rotation.
Claims (4)
円弧状に湾曲して工具回転中心に達する主刃が設けられ
、この主刃から周方向に離間した位置には先端が工具回
転中心から径方向外周側に後退する副刃が設けられてな
るボールエンドミルにおいて、 上記主刃のアキシャルレーキ角を負角に、上記副刃のア
キシャルレーキ角を正角に設定したことを特徴とするボ
ールエンドミル。(1) A main blade is provided on the outer periphery of the tip of the tool body, and at least the tip side is curved in a substantially arc shape and reaches the tool rotation center, and the tip is located at a position spaced apart from the main blade in the circumferential direction from the tool rotation center. A ball end mill provided with a secondary blade that retreats toward the outer circumferential side in the radial direction, characterized in that the axial rake angle of the main blade is set to a negative angle, and the axial rake angle of the secondary blade is set to a positive angle. .
るブレーカ溝を形成したことを特徴とする請求項１記載
のボールエンドミル。(2) The ball end mill according to claim 1, wherein a breaker groove extending along the main blade is formed on the rake face of the main blade.
向かうに従って漸次拡大させたことを特徴とする請求項
２記載のボールエンドミル。(3) The ball end mill according to claim 2, wherein the width of the breaker groove is gradually increased from the tip of the main blade toward the rear end.
後端側へ向かうに従って漸次増大させたことを特徴とす
る請求項２又は請求項３記載のボールエンドミル。(4) The ball end mill according to claim 2 or 3, wherein the groove depth of the breaker groove is gradually increased from the tip of the main blade toward the rear end.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2280109A JPH04159009A (en) | 1990-10-18 | 1990-10-18 | Ball end mill |
| KR1019910008435A KR960009592B1 (en) | 1990-10-18 | 1991-05-24 | Ball end mill |
| DE69102752T DE69102752T2 (en) | 1990-10-18 | 1991-10-17 | Ball end mill. |
| EP91117730A EP0482512B1 (en) | 1990-10-18 | 1991-10-17 | Ball end mill |
| US07/995,534 US5294219A (en) | 1990-10-18 | 1992-12-22 | Ball end mill |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2280109A JPH04159009A (en) | 1990-10-18 | 1990-10-18 | Ball end mill |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04159009A true JPH04159009A (en) | 1992-06-02 |
Family
ID=17620449
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2280109A Pending JPH04159009A (en) | 1990-10-18 | 1990-10-18 | Ball end mill |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPH04159009A (en) |
| KR (1) | KR960009592B1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8662800B2 (en) * | 2012-04-11 | 2014-03-04 | Sandvik Intellectual Property Ab | Cutting head with coolant channel |
| US20150043980A1 (en) * | 2012-03-29 | 2015-02-12 | Mitsubishi Materials Corporation | Ball end mill |
-
1990
- 1990-10-18 JP JP2280109A patent/JPH04159009A/en active Pending
-
1991
- 1991-05-24 KR KR1019910008435A patent/KR960009592B1/en not_active IP Right Cessation
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20150043980A1 (en) * | 2012-03-29 | 2015-02-12 | Mitsubishi Materials Corporation | Ball end mill |
| US9815127B2 (en) * | 2012-03-29 | 2017-11-14 | Mitsubishi Materials Corporation | Ball end mill |
| EP2832483B1 (en) | 2012-03-29 | 2019-08-28 | Mitsubishi Materials Corporation | Ball end mill |
| US8662800B2 (en) * | 2012-04-11 | 2014-03-04 | Sandvik Intellectual Property Ab | Cutting head with coolant channel |
Also Published As
| Publication number | Publication date |
|---|---|
| KR960009592B1 (en) | 1996-07-23 |
| KR920007725A (en) | 1992-05-27 |
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