201134582 六、發明說明： 【發明所屬之技術領域】 本發明是關於旋轉切削工具。 【先前技術】 印刷電路板加工等所使用的切型刀或金屬材料等加工 所使用的端銑刀等之旋轉切削工具，例如專利文獻1所示 ，已知有在工具的徑向後隙面設有可使外圍切削刃分離之 斷屑刃的旋轉切削工具。 [先行技術文獻] [專利文獻] [專利文獻1]日本特開2008- 1 1 43 08號公報 【發明內容】 [發明欲解決之課題] 然而，上述斷屑刃，爲了提昇切屑排出功能而設置， 但先前的旋轉切削工具說不上是獲得充分的切屑排出功能 ，因此現狀需求是要更加提昇切屑排出功能。 本發明是有鑑於上述所示的現狀，經發明者等進行了 各種檢討的結果，發現斷屑刃和鄰接在斷屑刃之工具旋轉 方向後方側的外圔切削刃之位置關係是會大幅左右斷屑刃 的切屑排出功能的提昇效果’終於完成本發明，提供一種 能夠極大提昇斷屑刃之切屑排出功能效果且實用性優越的 旋轉切削工具。 -5- 201134582 [用以解決課題之手段] 以下，參照附圖對本發明的主旨進行說明。 本發明相關的旋轉切削工具，係一種於工具本體1的 外圍從工具前端朝基端側形成有螺旋狀的複數切削排出溝 槽2，於該切削排出溝槽2的傾斜面和上述工具本體1的外 圍面或形成在上述工具本體1外圍的徑向後隙面的交叉稜 線部形成有外圍切削刃3，設有可使該外圍切削刃3分離的 複數斷屑刃4在上述工具本體1的上述外圍面或上述徑向後 隙面的旋轉切削工具，其特徵爲，在上述斷屑刃4的旋轉 軌跡一部份，構成爲重疊有40%以上比率之鄰接在該斷屑 刃4的工具旋轉方向後方側之上述外圍切削刃3的旋轉軌跡 此外，本發明相關的旋轉切削工具，係於申請專利範 圍第1項記載的旋轉切削工具中，其特徵爲，上述斷屑刃4 的旋轉軌跡和上述外圍切削刃3的旋轉軌跡之重疊比率是 指針對工具旋轉方向之上述斷屑刃4的長度，重疊在該斷 屑刃4旋轉軌跡之上述外圍切削刃3長度所佔的比率。 另外，本發明相關的旋轉切削工具，係於申請專利範 圍第2項記載的旋轉切削工具中，其特徵爲，上述斷屑刃4 的旋轉軌跡和上述外圍切削刃3的旋轉軌跡重疊的比率是 設定成40%以上且90%以下。 此外，本發明相關的旋轉切削工具，係於申請專利範 圍第2項記載的旋轉切削工具中，其特徵爲，上述斷屑刃4 201134582 的旋轉軌跡和上述外圍切削刃3的旋轉軌跡之重 設定成5 0 %以上且9 0 %以下。 另外，本發明相關的旋轉切削工具，係於申 圍第3項記載的旋轉切削工具中，其特徵爲，外 的長度是設定成上述斷屑刃4的長度的40%以上 下。 此外，本發明相關的旋轉切削工具，係於申 圍第4項記載的旋轉切削工具中，其特徵爲，外| 的長度是設定成上述斷屑刃4的長度的40%以上 下。 另外，本發明相關的旋轉切削工具，係於申 圍第3項記載的旋轉切削工具中，其特徵爲，外| 的長度是設定成上述斷屑刃4的長度的50%以上 下。 此外，本發明相關的旋轉切削工具，係於申 圍第4項記載的旋轉切削工具中，其特徵爲，外丨 的長度是設定成上述斷屑刀4的長度的50%以上 下。 另外，本發明相關的旋轉切削工具，係於申 圍第1項至第8項任一項記載的旋轉切削工具中， ，上述外圍切削刃3的旋轉軌跡是構成爲重疊在 刃4旋轉軌跡的工具基端側部份。 此外，本發明相關的旋轉切削工具，係於申 圍第1項至第8項任一項記載的旋轉切削工具中， 疊比率是 請專利範 圍切削刃3 且120%以 請專利範 1切削刃3 且120%以 請專利範 g切削刃3 且120%以 請專利範 園切削刃3 且120%以 請專利範 其特徵爲 上述斷屑 請專利範 其特徵爲 201134582 ，該工具是直徑爲1 .5mm以下。 另外’本發明相關的旋轉切削工具，係於申請專利範 圍第9項記載的旋轉切削工具中，其特徵爲，該工具是直 徑爲1 . 5 m m以下。 [發明效果] 由於本發明是構成爲如上述，因此就可成爲能夠極大 提昇斷屑刃之切屑排出功能效果且實用性優越的旋轉切削 工具。 【實施方式】 [發明之最佳實施形態] 接著，是根據圖面揭示本發明的作用對發明之最佳實 施形態進行簡單說明。當以旋轉的工具本體1的外圍切削 刃3接觸被切削物對該被切削物進行切削時，切屑，是會 從切屑排出溝槽2往指定方向（上方或下方）移動的同時 ，其一部份會經由斷屑刃4往工具旋轉方向後方側之鄰接 的切屑排出溝槽2移動。 此時，在斷屑刃4的旋轉軌跡一部份，若重疊有40 %以 上比率之鄰接在該斷屑刃4工具旋轉方向後方側的外圍切 削刃3的旋轉軌跡時，如第1圖所示通過斷屑刃4的切屑就 容易接觸（碰撞）該外圍切削刃3 (的傾斜面），藉由與 該外圍切屑刃3的接觸也可使切屑強制性往指定方向移動 -8 - 201134582 因此，切屑，不只是單純沿著切屑排出溝槽2移動而 已，藉由與鄰接在斷屑刃4之工具旋轉方向後側方側的外 圍切削刃3之接觸也能夠邊承受上方或下方的力邊強制性 受到引導往指定方向移動。 基於此，是可使切屑排出功能大幅改善，相對地耐折 損性、徑減量、刃塌量也就變良好。即，切屑的良好排出 ，是能夠抑制切屑黏附在被切削物或工具的傾斜面，能夠 防止切屑黏附造成的切削阻止增加及放熱性降低（切削溫 度上昇）所伴隨之工具的早期折損，此外，還能夠抑制徑 減量、刃塌量。 [實施例] 其次，是根據圖面對本發明的具體性實施例進行說明 〇 本實施例的旋轉切削工具，是於工具本體1的外圍從 工具前端朝基端側形成有螺旋狀的複數切削排出溝槽2， 於該切削排出溝槽2的傾斜面和上述工具本體1的外圍面或 形成在上述工具本體1外圔的徑向後隙面的交叉稜線部形 成有外圍切削刃3，設有可使該外圍切削刃3朝該外圍切削 刃3延設方向分離的複數斷屑刃4在上述工具本體1的上述 外圍面或上述徑向後隙面，如第1圖、第2圖所示，構成爲 是在上述斷屑刃4的旋轉軌跡一部份，重疊有4 0 %以上比率 之鄰接在該斷屑刃4工具旋轉方向後方側的外圍切削刃3的 旋轉軌跡。 -9- 201134582 具體而言，本實施例，是將本發明應用在前端部具有 底刃的同時基端部具有要和印刷電路板用外形加工機的工 具安裝部形成連結的刀柄部’安裝在印刷電路板用外形加 工機對印刷電路板等施以長孔加工或外形加工等切削加工 的切型刀，構成爲可使工具本體1邊朝右旋方向旋轉的同 時邊朝下方或主要往橫向（旋轉軸直角方向）移動進行被 切削物的切削，從工具上方（基端側）排出切屑。 此外，對於各部的詳細構成’是和一般廣泛使用之切 型刀的基本構成相同。即，是設有4個外圍切削刃3所謂4 片刃以上的構成（本實施例是6片刃的構成）各外圍切削 刃3分別設定成右螺旋’此外’各外圍切削刃3是等分割在 圓周方向，斷屑刃4沿著外圍切削刃3形成等距配設。另外 ，外圍切削刃3的螺旋角最好是設定在20°〜40°範圍。本實 施例中各外圍切削刃3的螺旋角是設定爲3 0 °。其理由是外 圍切削刃3的螺旋角若未滿20°則切屑排出功能會變差’若 超過40°則容易產生毛刺，導致折損壽命縮短。 此外，本實施例（下述實施例丨）中’斷屑刃4是設置 2條，沿著左螺旋方向形成排列設置’各螺旋角是設定成 64。。其他的實施例及比較例中’上述斷屑刃4的螺旋角是 根據重疊在該斷屑刃4旋轉軌跡之外圍切削刃3的長度進行 適當設定。該斷屑刃4的螺旋方向（排列設置方向）或剖 面形狀並無特別限定，可採用各種構成。 另，本實施例是針對本發明應用在切型刀的例子進行 說明，但並不限於應用在切型刀’也可應用在端銑刀等其 -10- 201134582 他的旋轉切削工具。此外，也可構成爲工具本體1朝左旋 方向旋轉進行切削，或從工具下方排出切屑等之構成等其 他的構成。 此外，構成爲在斷屑刃4的旋轉軌跡一部份，重疊有 鄰接在該斷屑刃4工具旋轉方向後方側的外圍切削刃3的旋 轉軌跡時，外圍切削刃3的旋轉軌跡，是也可如第2圖所示 構成爲重疊在斷屑刃4旋轉軌跡的工具基端側部份，也可 如第3圖所示構成爲重疊在斷屑刃4旋轉軌跡的工具前端側 部份。 本實施例中，如第2圖所示，外圍切削刃3的旋轉軌跡 ，是構成爲重疊在斷屑刃4旋轉軌跡的工具基端側部份。 其理由是，切屑排出溝槽2爲又螺旋時，當將向下的工具 本體1邊朝右旋方向旋轉邊進行加工時，切屑容易向上（ 工具基端側方向）排出，因此爲了讓更多的切屑接觸（碰 撞）工具的傾斜面，傾斜面位於工具基端側（上側）比較 能夠達到效果。 另外’本實施例中，斷屑刃4的旋轉軌跡和外圍切削 刃3的旋轉軌跡重疊的比率是設定成4 0 %以上且9 0 %以下’ 特別是以設定成5 0 %以上且9 0 %以下爲最佳。其理由是’ 未滿5 0 %時，切屑接觸的區域會變小，相對地切屑往工具 基端側的排出量或排出力會降低，此外，超過9〇%時’切 屑接觸的區域會變太大，相對地切屑容易黏附導致切削阻 力增加。 另’本實施例中，斷肩刃4的旋轉軌跡和外圍切削刃3 -11 - 201134582 的旋轉軌跡之重疊比率，是指工具旋轉方向之上述斷屑刃 4的長度和重疊在該斷屑刃4旋轉軌跡之外圍切削刃3的長 度比率。具體而言，如第4圖所示，是指斷屑刃4和外圍切 削刃3之重疊部份的長度[外圍切削刃3的長度B減掉切削刃 彼此重疊部份的長度P之後獲得的値（B-P)]除以斷屑刃的長 度C之後獲得的値（即（B-P)/C)。第4圖中，圖號A是外圍 切削刃3的節距。 此外，外圍切削刃3長度是設定成斷屑刃4長度的40% 以上且120%以下，特別是以50%以上且120%以下爲最佳。 其理由是，未滿50%時，切屑接觸的區域會變小，相對地 切屑往工具基端側的排出量或排出力會降低，此外，超過 12 0%時，外圍切削刃3彼此重疊的比率會太大導致切削阻 力增加。又，斷屑刃4的長度變太短以致切屑難以從切屑 排出溝槽2排出。 另外，工具直徑是設定成1.5 mm以下。工具直徑爲 1.5mm以下，特別是0.8mm以下的工具，是使用在非常高 的切削速度（周速），因此上述構成造成的切屑排出功能 提昇效果就極爲顯著。 由於本實施例是構成爲上述，因此當以旋轉的工具本 體1的外圍切削刃3接觸被切削物對該被切削物進行切削時 ，切屑，是會從切屑排出溝槽2往上方移動的同時，其一 部份會經由斷屑刃4往工具旋轉方向後方側之鄰接的切屑 排出溝槽2移動。 此時，在斷屑刃4的旋轉軌跡一部份，若重疊有4 0 %以 -12- 201134582 上且90%以下比率之鄰接在該斷屑刃4工具旋轉方向後方側 的外圍切削刃3的旋轉軌跡時’如第1圖所示通過斷屑刃4 的切屑就容易接觸（碰撞）該外圍切削刃3 (的傾斜面） ，藉由與該外圍切屑刃3的接觸就可使切屑強制性往上方 移動，重覆著切屑往鄰接之切屑排出溝槽2的移動和與外 圍切削刃3的接觸，如第1圖所示’就可使切屑成階梯狀向 上排出。 因此，切屑，不只是單純沿著切屑排出溝槽2移動而 已，藉由與鄰接在斷屑刃4之工具旋轉方向後側方側的外 圍切削刃3之接觸也能夠邊承受上方或下方的力邊強制性 受到引導往指定方向移動。 關於這點，例如鄰接在斷屑刃4’之工具旋轉方向後方 側的工具本體1 ’之外圍切削刃3 ’的旋轉軌跡未滿4〇%之第5 圖所示的工具，切屑往鄰接的切屑排出溝槽2 ’移動後，與 外圍切削刃3 ’不會產生接觸，如第5圖的箭頭符號所示， 只是單純通過斷屑刃4’，因此就不會產生藉由與外圍切削 刃3 ’接觸造成之強制性往上方的移動作用。 基於此，本實施例的上述構成是可使切屑排出功能大 幅改善，相對地耐折損性、徑減量、刃塌量也就變良好。 即’切屑的良好排出，是能夠抑制切屑黏附在被切削物或 工具的傾斜面，能夠防止切屑黏附造成的切削阻止增加及 放熱性降低（切削溫度上昇）所伴隨之工具的早期折損， 此外，還能夠抑制徑減量、刃塌量。 根據以上所述，本實施例，是可成爲能夠極大提昇斷 -13- 201134582 屑刃之切屑排出功能效果且實用性優越的旋轉切削工具。 接著，是對可驗證本實施例效果的實驗例進行說明。 第6圖，是表示對外圍切削刃的節距A、外圍切削刃的 長度B、斷屑刃的長度C、切削刃彼此重疊部份的長度p進 行各種改變後藉此評價工具切屑排出壽命的實驗條件及實 驗結果表。 根據第6圖，是可確認出相較於斷屑刃的旋轉軌跡和 外圍切削刃的旋轉軌跡之重疊比率（B-P)/C未滿40%或超過 9 0%時，外圍切削刃的長度爲斷屑刃長度的比率B/C未滿 40%或超過120%時的比較例1〜5，滿足上述本實施例條件 的實施例1〜3，其切屑排出壽命變良好。 具體而言，切屑排出壽命，是針對印刷電路板，在同 一條件（指定的旋轉數、指定的進刀速度）下重覆進行如 第9圖所示長度0.1 5m之切槽的切槽加工，對切屑堵塞率達 到第7圖、第8圖所示的50%爲止的加工距離（直到出現切 槽長度的50%堵塞有切屑時的切槽爲止的加工距離、切屑 排出壽命）進行了比較。另，第9 ( a )圖爲使用實施例1 ，第9 ( b )圖爲使用比較例3相關的工具進行力□工後的電 路板。 例如：根據第7圖，是可確認出比較例1、2、3的切屑 排出壽命分別爲8.15m、5.43m、3.58m，相對於此’實施 例1的切屑排出壽命飛躍性增長爲1 1 ·1 7 m。同樣地，根據 第8圖，是可確認出比較例4、5的切屑排出壽命分別爲 24.00m、4.63m，相對於此，實施例7的切屑排出壽命飛躍 -14- 201134582 性增長爲3 1 . 8 5 m。 根據以上所述，可確認斷屑刃的旋轉軌跡和外圍刃的 旋轉軌跡之重疊比率（B-P)/C爲40%以上且90%以下，外圍 切削刀長度爲斷屑刃長度的比率B/C爲40%以上且120%以 下，是能夠使斷屑刃和鄰接在斷屑刃之工具旋轉方向後方 側的外圍切削刃之位置關係爲最佳化，能夠大幅改善切屑 排出功能，進而能夠使切屑排出壽命長期化。 【圖式簡單說明】 第1圖爲本實施例的要部槪略說明側面圖。 第2圖爲本實施例的要部槪略說明圖。 第3圖爲本實施例的要部槪略說明圖。 第4圖爲本實施例的要部放大槪略說明圖。 第5圖爲先前例的要部槪略說明側面圖。 桌6圖爲表不實施例的實驗條件及實驗結果表。 第7圖爲實施例及比較例的切屑排出壽命比較圖。 第8圖爲實施例及比較例的切屑排出壽命比較圖。 第9圖爲實施例及比較例的加工結果比較照片。 【主要元件符號說明】 1 :工具本體 2 :切屑排出溝槽 3 :外圍切削刃 4 :斷屑刃 -15-201134582 VI. Description of the Invention: TECHNICAL FIELD OF THE INVENTION The present invention relates to a rotary cutting tool. [Prior Art] A rotary cutting tool such as an end mill or a metal material used for processing such as a printed circuit board processing, for example, as disclosed in Patent Document 1, is known to have a radial flank surface of the tool. A rotary cutting tool with a chip breaker that separates the peripheral cutting edges. [PRIOR ART DOCUMENT] [Patent Document 1] [Patent Document 1] JP-A-2008- 1 1 43 08 SUMMARY OF INVENTION [Problem to be Solved by the Invention] However, the chip breaker is provided to enhance the chip discharge function. However, the previous rotary cutting tool does not provide sufficient chip discharge function, so the current demand is to further improve the chip discharge function. In view of the above-described state of the art, the inventors have conducted various reviews, and found that the positional relationship between the chip breaker and the outer cutting edge adjacent to the tool rotating direction of the chip breaker is greatly changed. The lifting effect of the chip discharge function of the chip breaker is finally completed. The present invention provides a rotary cutting tool which can greatly improve the chip discharge function of the chip breaker and is excellent in practicability. -5-201134582 [Means for Solving the Problems] Hereinafter, the gist of the present invention will be described with reference to the drawings. The rotary cutting tool according to the present invention is a spiral-shaped plurality of cutting discharge grooves 2 formed on the periphery of the tool body 1 from the tool front end toward the base end side, the inclined surface of the cutting discharge groove 2 and the tool body 1 The peripheral surface or the intersecting ridge portion formed on the radial flank surface of the periphery of the tool body 1 is formed with a peripheral cutting edge 3 provided with a plurality of chip breaking edges 4 for separating the peripheral cutting edges 3 at the above-mentioned periphery of the tool body 1 The rotary cutting tool of the surface or the radial flank surface is characterized in that a portion of the rotation path of the chip breaker 4 is overlapped by a ratio of 40% or more adjacent to the tool rotation direction of the chip breaker 4 Further, the rotary cutting tool according to the first aspect of the invention is characterized in that the rotary cutting tool according to the first aspect of the invention is characterized in that the rotation path of the chip breaker 4 and the periphery are The overlapping ratio of the rotational trajectories of the cutting edge 3 is the length of the above-described chip breaking edge 4 in the direction of rotation of the tool, and the peripheral cutting edge 3 overlapping the rotational path of the chip breaking edge 4 The ratio of the length. Further, the rotary cutting tool according to the second aspect of the invention is characterized in that the ratio of the rotation locus of the chip breaker 4 to the rotation locus of the peripheral cutting edge 3 is It is set to 40% or more and 90% or less. Further, the rotary cutting tool according to the second aspect of the invention is characterized in that the rotary cutting path of the chip breaker 4 201134582 and the rotation path of the peripheral cutting edge 3 are set. It is more than 50% and less than 90%. Further, the rotary cutting tool according to the third aspect of the present invention is characterized in that the outer length is set to be 40% or more of the length of the chip breaker 4. Further, the rotary cutting tool according to the fourth aspect of the invention is characterized in that the length of the outer portion is set to be 40% or more of the length of the chip breaker 4. Further, the rotary cutting tool according to the third aspect of the present invention is characterized in that the length of the outer portion is set to be 50% or more of the length of the chip breaker 4. Further, the rotary cutting tool according to the fourth aspect of the invention is characterized in that the length of the outer casing is set to be 50% or more of the length of the chip breaker 4. Further, in the rotary cutting tool according to any one of the items 1 to 8, the rotary cutting tool of the peripheral cutting edge 3 is configured to overlap the rotation locus of the blade 4. The base side of the tool. Further, the rotary cutting tool according to the present invention is the rotary cutting tool according to any one of items 1 to 8, wherein the stacking ratio is the patent range cutting edge 3 and 120% to request the patent vane 1 cutting edge. 3 and 120% of the patents are required to cut the edge 3 and 120% to request the patent cutting edge 3 and 120% to request the patent. The characteristics of the patent are the above-mentioned chip breaking patent. The characteristic is 201134582, the tool is 1 in diameter. .5mm or less. Further, the rotary cutting tool according to the invention is the rotary cutting tool according to the ninth aspect of the invention, wherein the tool has a diameter of 1.5 m or less. [Effect of the Invention] Since the present invention is configured as described above, it is possible to provide a rotary cutting tool which is capable of greatly improving the chip discharge function of the chip breaker and which is excellent in practicability. [Embodiment] BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a best mode for carrying out the invention will be briefly described by showing the effects of the present invention. When the peripheral cutting edge 3 of the rotating tool body 1 contacts the workpiece to cut the workpiece, the chip moves from the chip discharge groove 2 in a predetermined direction (upper or lower), and a part thereof The portion moves through the chip breaker 4 to the adjacent chip discharge groove 2 on the rear side in the tool rotation direction. At this time, if a rotation trajectory of the peripheral cutting edge 3 adjacent to the tool rotating direction of the chip breaking edge 4 is overlapped by a portion of the rotation path of the chip breaking edge 4, as shown in FIG. It is shown that the chips passing through the chip breaker 4 easily contact (collide) the (inclined surface) of the peripheral cutting edge 3, and the contact with the peripheral chip edge 3 can also force the chips to move in a specified direction - 201134582 , the chip, not only simply moves along the chip discharge groove 2, but also can withstand the force of the upper or lower side by contact with the peripheral cutting edge 3 on the side of the rear side of the tool rotating direction of the chip breaking edge 4. Mandatory to be guided to move in the specified direction. Based on this, the chip discharge function can be greatly improved, and the relative resistance to breakage, the amount of diameter reduction, and the amount of blade collapse are also improved. In other words, the good discharge of the chips can prevent the chips from adhering to the inclined surface of the workpiece or the tool, and can prevent the increase in the cutting prevention due to the adhesion of the chips and the early breakage of the tool due to the decrease in the heat release property (the cutting temperature rises). It is also possible to suppress the amount of diameter reduction and the amount of blade collapse. [Embodiment] Next, a specific embodiment of the present invention will be described with reference to the drawings. The rotary cutting tool of the present embodiment is formed with a spiral plurality of cutting discharges from the front end side of the tool toward the base end side at the periphery of the tool body 1. The groove 2 is formed with a peripheral cutting edge 3 at an inclined surface of the cutting discharge groove 2 and a peripheral surface of the tool body 1 or a cross ridge portion formed on a radial flank surface of the outer periphery of the tool body 1 The plurality of chip breakers 4 that separate the peripheral cutting edge 3 in the direction in which the peripheral cutting edge 3 is extended are formed on the outer peripheral surface or the radial flank surface of the tool body 1 as shown in FIGS. 1 and 2 In order to be part of the rotation locus of the chip breaker 4, a rotational trajectory of the peripheral cutting edge 3 adjacent to the rear side of the cutter blade 4 in the tool rotation direction is superimposed with a ratio of 40% or more. -9- 201134582 Specifically, in the present embodiment, the present invention is applied to a shank portion in which the base end portion has a bottom edge and the tool end portion to be connected to the tool mounting portion of the outer shape processing machine for a printed circuit board. A cutting blade that applies a long hole machining or a shape machining to a printed circuit board or the like by a profile processing machine for a printed circuit board, and is configured such that the tool body 1 can be rotated in the right-hand direction while facing downward or mainly toward The lateral direction (rotational axis direction) moves to cut the workpiece, and the chips are discharged from the upper side (base end side) of the tool. Further, the detailed configuration of each part is the same as the basic configuration of a generally used cutting blade. In other words, it is a configuration in which four peripheral cutting edges 3 are provided with four or more blades (in the present embodiment, six blades are formed), and each of the peripheral cutting edges 3 is set to a right spiral 'further'. Each of the peripheral cutting edges 3 is equally divided in the circumference. In the direction, the chip breaking edge 4 is formed equidistantly along the peripheral cutting edge 3. Further, the helix angle of the peripheral cutting edge 3 is preferably set in the range of 20 to 40. In the present embodiment, the helix angle of each of the peripheral cutting edges 3 is set to 30 °. The reason is that if the helix angle of the outer peripheral cutting edge 3 is less than 20°, the chip discharge function is deteriorated. If it exceeds 40°, burrs are likely to occur, and the breakage life is shortened. Further, in the present embodiment (the following embodiment 丨), "the chip breaking blades 4 are provided in two pieces, and are arranged in the left spiral direction." The respective helix angles are set to 64. . In the other embodiments and comparative examples, the helix angle of the chip breaker 4 is appropriately set in accordance with the length of the peripheral cutting edge 3 which is superimposed on the rotation locus of the chip breaker 4. The spiral direction (arrangement direction) or the cross-sectional shape of the chip breaker 4 is not particularly limited, and various configurations can be employed. Further, the present embodiment is described with respect to the example in which the present invention is applied to a cutting blade, but it is not limited to the application of the cutting blade', and can be applied to an end cutting tool or the like. Further, other configurations such as a configuration in which the tool body 1 is rotated in the left-hand direction to cut, or a chip or the like is discharged from the lower side of the tool may be employed. Further, when a rotation locus of the peripheral cutting edge 3 adjacent to the tool rotation direction of the chip breaker 4 is superimposed on a part of the rotation locus of the chip breaker 4, the rotation locus of the peripheral cutting edge 3 is also As shown in Fig. 2, the tool base end portion which is superposed on the rotation path of the chip breaker 4 may be formed so as to overlap the tool tip end portion of the chip breaking blade 4 as shown in Fig. 3. In the present embodiment, as shown in Fig. 2, the rotational locus of the peripheral cutting edge 3 is a portion on the proximal end side of the tool which is superposed on the rotation locus of the chip breaker 4. The reason is that when the chip discharge groove 2 is spiraled again, when the downward direction of the tool body 1 is rotated in the right-hand direction, the chips are easily discharged upward (in the direction of the tool base end side), so in order to make more The sloping surface of the chip contact (collision) tool, the inclined surface is located on the tool base end side (upper side). Further, in the present embodiment, the ratio of the rotation locus of the chip breaker 4 and the rotation locus of the peripheral cutting edge 3 is set to be 40% or more and 90% or less 'in particular, it is set to 50% or more and 9 0 % below is the best. The reason is that when the temperature is less than 50%, the area where the chips contact will become smaller, and the discharge amount or discharge force of the chips toward the base end side of the tool will decrease. In addition, when the amount exceeds 9〇%, the area where the chip contacts will change. Too large, relatively easy to adhere to the chips, resulting in increased cutting resistance. In the present embodiment, the overlapping ratio of the rotational trajectory of the shoulder blade 4 and the rotational trajectory of the peripheral cutting edge 3 -11 - 201134582 refers to the length of the chip breaking edge 4 in the direction of rotation of the tool and overlaps the chip breaking edge. 4 The ratio of the length of the peripheral cutting edge 3 of the rotation track. Specifically, as shown in Fig. 4, it means the length of the overlapping portion of the chip breaker 4 and the peripheral cutting edge 3 [the length B of the peripheral cutting edge 3 minus the length P of the overlapping portion of the cutting edges)値(BP)] is divided by the length C of the chip breaker (ie (BP)/C). In Fig. 4, the reference number A is the pitch of the peripheral cutting edges 3. Further, the length of the peripheral cutting edge 3 is set to be 40% or more and 120% or less of the length of the chip breaker 4, and particularly preferably 50% or more and 120% or less. The reason is that when the temperature is less than 50%, the area where the chips contact is reduced, and the discharge amount or the discharge force of the chips toward the base end side of the tool is lowered, and when the temperature exceeds 120%, the peripheral cutting edges 3 overlap each other. The ratio will be too large and the cutting resistance will increase. Further, the length of the chip breaker 4 becomes too short so that the chips are hard to be discharged from the chip discharge groove 2. In addition, the tool diameter is set to 1.5 mm or less. The tool having a diameter of 1.5 mm or less, particularly 0.8 mm or less, is used at a very high cutting speed (peripheral speed), so that the chip discharge function effect by the above-described configuration is extremely remarkable. Since the present embodiment is configured as described above, when the peripheral cutting edge 3 of the rotating tool body 1 contacts the workpiece to cut the workpiece, the chips move upward from the chip discharge groove 2. A part of it moves through the chip breaker 4 to the adjacent chip discharge groove 2 on the rear side in the tool rotation direction. At this time, in a part of the rotation trajectory of the chip breaking edge 4, if the overlap is 40% to -12-201134582 and the ratio of 90% or less is adjacent to the peripheral cutting edge 3 on the rear side of the tool turning direction of the chip breaker 4 When the rotation path is traversed, the chip passing through the chip breaking edge 4 as shown in Fig. 1 easily contacts (collides) the (inclined surface) of the peripheral cutting edge 3, and the chip is forced by the contact with the peripheral chip edge 3. The movement moves upward, repeating the movement of the chips to the adjacent chip discharge grooves 2 and the contact with the peripheral cutting edge 3, as shown in Fig. 1 , the chips can be discharged in a stepped manner. Therefore, the chips are not only simply moved along the chip discharge groove 2, but also can withstand the force above or below by the contact with the peripheral cutting edge 3 on the side of the rear side of the tool cutting direction of the chip breaker 4. It is mandatory to be guided to move in the specified direction. In this regard, for example, the tool shown in Fig. 5, in which the rotational path of the peripheral cutting edge 3' of the tool body 1' adjacent to the tool rotating body 1' on the rear side in the tool rotation direction of the chip breaking blade 4' is not adjacent to the tool shown in Fig. 5, the chips are adjacent to each other. After the chip discharge groove 2' is moved, it does not come into contact with the peripheral cutting edge 3'. As indicated by the arrow symbol in Fig. 5, it simply passes through the chip breaker 4', so that it does not occur with the peripheral cutting edge. 3 'The forced movement of the upper part caused by the contact. In view of the above, the above-described configuration of the present embodiment can greatly improve the chip discharge function, and the relative fracture resistance, the diameter reduction amount, and the blade collapse amount are also improved. In other words, it is possible to prevent the chips from adhering to the inclined surface of the workpiece or the tool, and to prevent the increase in the cutting prevention due to the adhesion of the chips and the early breakage of the tool due to the decrease in the heat release property (increased cutting temperature). It is also possible to suppress the amount of diameter reduction and the amount of blade collapse. According to the above description, the present embodiment is a rotary cutting tool which can greatly improve the chip discharge function of the cutting edge of the cutting edge and is practical. Next, an experimental example in which the effects of the present embodiment can be verified will be described. Fig. 6 is a view showing the evaluation of the chip discharge life of the tool by varying the pitch A of the peripheral cutting edge, the length B of the peripheral cutting edge, the length C of the chip breaker, and the length p of the portion where the cutting edges overlap each other. Experimental conditions and experimental results. According to Fig. 6, it can be confirmed that the length of the peripheral cutting edge is the ratio of the rotation trajectory of the chip breaking edge and the rotation trajectory of the peripheral cutting edge (BP)/C less than 40% or more than 90%. In Comparative Examples 1 to 5 in which the ratio B/C of the chip breaking edge length B/C was less than 40% or more than 120%, the chip discharge life of the examples 1 to 3 satisfying the conditions of the above-described examples became good. Specifically, the chip discharge life is a grooving process in which the slit of 0.15 m in length shown in Fig. 9 is repeated under the same conditions (the specified number of rotations, the specified feed rate) for the printed circuit board. The machining distance (the machining distance and the chip discharge life until the cleavage at the time of 50% of the grooving clogging) was compared with the machining squeezing rate of 50% as shown in Fig. 7 and Fig. 8 was compared. Further, the figure 9 (a) shows the use of the embodiment 1, and the figure 9 (b) shows the circuit board after the force is applied using the tool of the comparative example 3. For example, according to Fig. 7, it can be confirmed that the chip discharge life of Comparative Examples 1, 2, and 3 is 8.15 m, 5.43 m, and 3.58 m, respectively, and the chip discharge life of the first embodiment is dramatically increased to 1 1 . · 1 7 m. Similarly, according to Fig. 8, it can be confirmed that the chip discharge life of Comparative Examples 4 and 5 is 24.00 m and 4.63 m, respectively, whereas the chip discharge life of Example 7 is leap-14-201134582. The growth is 3 1 . 8 5 m. According to the above, it can be confirmed that the overlap ratio (BP)/C of the rotation locus of the chip breaker and the rotation locus of the peripheral edge is 40% or more and 90% or less, and the peripheral cutter length is the ratio of the length of the chip breaker B/C. 40% or more and 120% or less, the positional relationship between the chip breaker and the peripheral cutting edge adjacent to the tool rotating direction of the chip breaker can be optimized, and the chip discharge function can be greatly improved, and the chip can be further swarf The discharge life is long-term. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side elevational view of the essential part of the embodiment. Fig. 2 is a schematic explanatory view of essential parts of the embodiment. Fig. 3 is a schematic explanatory view of essential parts of the embodiment. Fig. 4 is an enlarged schematic explanatory view of an essential part of the embodiment. Fig. 5 is a side elevational view of the main part of the previous example. Table 6 is a table showing the experimental conditions and experimental results of the examples. Fig. 7 is a graph showing the comparison of the chip discharge life of the examples and the comparative examples. Fig. 8 is a graph showing the comparison of the chip discharge life of the examples and the comparative examples. Fig. 9 is a comparison photograph of the processing results of the examples and comparative examples. [Main component symbol description] 1 : Tool body 2 : Chip discharge groove 3 : Peripheral cutting edge 4 : Chip breaker -15-