200900183 九、發明說明 【發明所屬之技術領域】 本發明係關於鑽孔工具。 【先前技術】 一般印刷配線板（PCB )用的鑽孔鑽頭’例如第1圖 所示，以既定的扭轉角/5，設置一對切屑排出槽2 1、2 2 ’ 在該切屑排出槽21、2 2和第一離隙面2 3、2 4的交叉稜線 部25、26，形成具有既定的前端角Τ’之刀刃。圖中，符 號2 8、2 9代表第二離隙面。 因此，第1圖的工具合計有4個前端面’藉由對各前 端面（離隙面）賦予既定的角度，以在工具前端中央附近 形成鑿尖（chisel edge) 27。第1 (a)圖爲俯視圖，第1 (b )圖爲前視圖，第1 ( c )圖爲右側視圖。 然而，隨著近年來電子機器的高集成化、高密度化， 變得必須對P C B實施極小徑加工，因此鑽頭也有更加小 徑化的必要。 例如甚至可能會有使用工具徑0 · 0 5 m m程度之極小徑 鑽頭的情形，由於工具的剛性極小，發生折損的可能性變 高’必須頻繁地更換工具，或在重疊PCB時必須減少同 時加工的片數等。 又在前端形狀的外觀檢查方面，是測定左右的平衝（ 刀刃的偏位及鏊尖的偏心）來判定是否合格，若鑽頭徑變 小’除加工以外，該檢查作業也變得相當麻煩。 -5- 200900183 於是，例如專利文獻1揭示出，即使是小徑的工具仍 能確保剛性之單刃鑽頭的構造，但尙無法獲得充分的折損 壽命。又其前端面有複數個，和以往同樣的其合格判定檢 查作業相當麻煩。 [專利文獻1]日本特開2003-311522號公報 【發明內容】 本發明是有鑑於上述現狀而構成者，其目的是提供一 種實用性極優異的鑽孔工具，就算做成極小徑的鑽孔工具 仍不容易折損’不須進行頻繁地更換，形狀簡單而容易進 行製造及檢查。 參照附圖來說明本發明的要旨。 一種鑽孔工具’係具備一或複數個螺旋狀的切屑排出 槽1' 2之鑽孔工具，其特徵在於：在前端部設置不存在 與工具中心軸交叉的稜線之平坦的前端面5。 在請求項1記載的鑽孔工具，前述前端面5，相對於 工具中心軸以既定的傾斜角度α傾斜。 又在請求項1記載的鑽孔工具，工具徑爲〇.2mm以 下。 又在請求項2記載的鑽孔工具，工具徑爲〇. 2mm以 下。 又在請求項1〜4中任一項記載的鑽孔工具，在複數 個前述切屑排出槽1、2之間設置島部3、4，在前述切屑 排出槽1、2和前述前端面5所形成之複數個交叉稜線部 -6- 200900183 6、7中’在較長的交叉稜線部6上具有最前端點，以讓 前述交叉稜線部6發揮切削作用。 又在請求項1〜4中任一項記載的鑽孔工具，在複數 個前述切屑排出槽1、2之間設置島部3、4，在該島部3 、4和前述前端面5所形成之複數個交叉稜線部8、9中 ，在較長的交叉稜線部8上具有最前端點，以讓前述交叉 稜線部8發揮切削作用。 又在請求項5記載的鑽孔工具，將前述前端面5對工 具中心軸的傾斜角度α設定在0°〜（90°-扭轉角）的範圍 〇 又在請求項6記載的鑽孔工具，將前述前端面5對工 具中心軸的傾斜角度α設定在0°〜（90°-扭轉角）的範圍 〇 又在請求項7記載的鑽孔工具，將前述傾斜角度α設 定在10°〜30°的範圍。 又在請求項8記載的鑽孔工具’將前述傾斜角度α設 定在1 0°〜3 0°的範圍。 本發明由於具備上述構成，可提供一種實用性極優異 的鑽孔工具，就算做成極小徑的鑽孔工具仍不容易折損， 不須進行頻繁地更換，形狀簡單而容易進行製造及檢查。 【實施方式】 根據圖式簡單說明本發明的較佳實施形態及其作用。 本實施形態的構成’是在工具前端設置1個不存在棱 200900183 線之平坦的前端面5，不同於一般的鑽頭（例如在工 端中央附近具有鑿尖，連續於該鑿尖而設置形成既定 角之刀刃），由於孔加工中之切削阻力幾乎都是在推 向承受，而能減輕工具軸直角方向的外力（孔加工中 削阻力）所產生之彎曲應力，因此不容易發生折損。 再者，是在前端面5最突出的部分（和島部或切 出槽所形成的交叉稜線部）抵接於工件加工面下逐漸 切削，而不同於上述一般的鑽頭，由於不容易咬入加 ，在切削初期工具會稍搖動，而邊將入口側的孔徑適 擴大邊進行鑽孔，因此加工孔的孔徑變成越靠入口側 ，如此工具的基端側不容易接觸加工孔內壁，而能抑 工具基端側接觸加工孔內壁所造成的折損。 又其形狀簡單，只要將形成有切屑排出槽之工具 前端部在適當的位置用適當的角度除去即可，因此容 成具有期望的截面形狀及期望的傾斜角度α之前端面 又，由於前端面5只有1個，不會像具有複數個 面的工具那樣發生各前端面的左右不平衡，因此不須 左右的平衡檢查。又由於未形成複數個離隙面（前端 ’不須進行離隙面寬度的檢查，可簡化檢查並提昇良 [實施例] 根據第2圖〜第6圖來說明本發明的具體實施例 本實施例之鑽孔工具’如第2圖所示，係設有螺 的第一切屑排出槽1及螺旋狀的第二切屑排出槽2， I—t ^ /. 具則 前端 力方 的切 屑排 進行 工面 度的 越大 制因 材的 易形 5。 前端 進行 面） 率。 旋狀 而在 -8 - 200900183 切屑排出槽1、2彼此間形成島部3、4，其在前端 1個不存在與工具中心軸交叉的稜線之平坦的前端 在圖中’符號6、7代表切屑排出槽1、2和前端面 成的交叉稜線部，符號8、9代表島部3、4和前端 形成的交叉稜線部。 具體而言，本實施例係將本發明適用於工具徑 的最大外徑）〇. 〇 5 mm極小徑的雙槽鑽頭。但並不 槽鑽頭，也能適用於單槽鑽頭等其他的鑽頭。又並 極小工具，也能適用於工具徑超過〇.2mm之一般 〇 接著具體說明各部位。 前端面5相對於工具中心軸以既定的傾斜角度 。該傾斜角度α較佳爲設定成，在與工具軸直角方 的角度以上（0°以上）〜90。-切屑排出槽的扭轉角 角度。在比90°-扭轉角（本實施例爲45° )更大的 亦即比90°-45° = 45°更大的角度的情形，工具前端 尖而容易發生缺口，會因前端缺口而造成切削能力 導致折損壽命變短。具體而言，本實施例的前端面 角度α設定成20。。 本實施例的前端面5，係在工具材形成有切屑 1、2的狀態下，將該工具材的前端部在既定位置 的角度除去，藉此形成期望的前端面形狀及期望的 度α，前端面5的形狀大致分成以下2個形狀。 第1個構造，如第3圖所示’是在切屑排出平 部設有 面5。 5所形 面5所 (刃部 限於雙 不限於 的工具 α傾斜 向平行 以下的 角度， 變得過 變差， 之傾斜 排出槽 用既定 傾斜角 I 1、2 -9- 200900183 和前端面5所形成之複數個交叉稜線部6、7中， 的交叉稜線部6上具有最前端點（最初接觸工件的 以讓前述交叉稜線部6發揮切削作用。第2個構造 4圖所示，是在島部3、4和前端面5所形成之複 叉稜線部8、9中，在較長的交叉稜線部8上具有 點，以讓前述交叉稜線部8發揮切削作用。又第： 中，將傾斜角度α設定成3 0 °。 在第2圖的本實施例，是採用第1個構造，這 於最前端點不在島部3、4(外周）上，不容易受 軸直角方向的外力，能謀求穩定的長壽命化。又在 構造，由於最前端點在島部3、4(外周）上，可 削能力，而獲得良好的孔品質（孔位置精度，孔內 度）。 本實施例由於具備上述構成，雖然不存在前端 (鑿尖）或是一般具有前端角的刀刃等之外力集中 ，故較難咬住，但不容易受到工具軸直角方向的外 此前端面5和切屑排出槽的傾斜面（rake face )所 交叉稜線部可逐漸進行加工面之加工’故不容易發 前端的損傷。 再者，是在前端面5最突出的部分和切屑排出 形成的交叉稜線部6抵接於加工面下逐漸進行切削 如上述般不容易咬入加工面，工具會稍搖動而邊將 的孔徑適度的擴大邊進行鑽孔’因此加工孔的孔徑 靠入口側越大，如此工具的基端側不容易接觸加工 在較長 點）， ，如第 數個交 最前端 i、4圖 時，由 到工具 第2個 提昇切 壁面粗 尖銳部 的部分 力，因 形成的 生工具 槽1所 ，由於 入口側 變成越 孔內壁 -10- 200900183 ，而能抑制因工具基端側接觸加工孔內壁所造成的折損。 又其形狀簡單，只要將形成有切屑排出槽之工具材的 前端部在適當的位置用適當的角度除去即可，因此容易進 行製造。 又，由於前端面5只有1個，不會像具有複數個前端 面的工具那樣發生各前端面的左右不平衡，因此不須進行 左右的平衡檢查。又由於未形成複數個離隙面（前端面） ，不須進行離隙面寬度的檢查，可簡化檢查並提昇良率。 又，在工具徑爲〇.2mm以下的工具的情形，能顯著 的發揮上述效果。亦即，在工具爲小徑的情形，在切削初 期該工具前端容易發生損傷，本實施例的構造可儘量減低 此削初期的外力，故相當有用。 因此，在本實施例可提供一種實用性極優異的鑽孔工 具，就算做成極小徑的鑽孔工具仍不容易折損，不須進行 頻繁地更換，形狀簡單而容易進行製造及檢查。 接著說明用來佐證上述效果的實驗例。 如第5圖所示，對於設有1個不存在稜線的平坦前端 面之工具（實施例）和第1圖所示的工具（習知例）的兩 者的工具壽命，以對PCB的鑽擊（hit )數進行比較的結 果，若採用前端面不存在稜線之唯一的平坦面，比起習知 之具有多數個前端面（前端離隙面）的構造，其工具壽命 變長約2倍左右。 又如第6圖所示，使不存在棱線之平坦前端面的傾斜 角度在〇° (第5圖的實施例）〜45°變化，對PCB的鑽擊 -11 - 200900183 數比較工具壽命的結果’確認出在〇°〜45°的範圍其折損 壽命比習知例更長’而在1〇。〜30°的範圍折損壽命特別長 【圖式簡單說明】 第1圖係習知例的槪略說明圖。 第2圖係本實施例的槪略說明圖。 第3圖係用來說明前端形狀之槪略說明圖。 第4圖係用來說明前端形狀之槪略說明圖。 第5圖係用來比較本實施例和習知例的工具壽命之表 〇 第6圖係前端面的不同傾斜角度的工具壽命之比較圖 【主要元件符號說明】 1、2 :切屑排出槽 3、4 :島部 5 :前端面 6 ' 7 ：(切屑排出槽和前端面所形成的）交叉稜線部 8、9 :(島部和前端面所形成的）交叉稜線部 α :傾斜角度 -12-200900183 IX. Description of the Invention [Technical Field of the Invention] The present invention relates to a drilling tool. [Prior Art] A drill bit for a general printed wiring board (PCB) is provided with a pair of chip discharge grooves 2 1 and 2 2 ' at a predetermined discharge angle /5 as shown in Fig. 1, in which the chip discharge groove 21 is provided. The intersecting ridge portions 25, 26 of the second and second relief faces 2 3, 2 4 form a blade having a predetermined front end angle Τ'. In the figure, symbols 2 8 and 2 9 represent the second relief surface. Therefore, the tool of Fig. 1 has a total of four front end faces, and a chisel edge 27 is formed near the center of the front end of the tool by giving a predetermined angle to each of the front end faces (the relief faces). Figure 1 (a) is a top view, Figure 1 (b) is a front view, and Figure 1 (c) is a right side view. However, with the recent increase in the integration and density of electronic devices, it has become necessary to perform extremely small diameter machining on P C B, and therefore, it is necessary to reduce the diameter of the drill. For example, there may even be cases where a very small diameter drill with a tool diameter of 0 · 0 5 mm is used. Since the rigidity of the tool is extremely small, the possibility of breakage becomes high. 'The tool must be frequently changed, or the simultaneous processing must be reduced when overlapping the PCB. The number of pieces, etc. In the inspection of the appearance of the front end shape, it is determined whether the left and right flat punches (the offset of the blade edge and the eccentricity of the tip end) are judged to be acceptable, and if the drill diameter is small, the inspection work becomes quite troublesome except for the machining. -5- 200900183 Thus, for example, Patent Document 1 discloses that even a small-diameter tool can secure a structure of a rigid single-blade drill, but a sufficient breakage life cannot be obtained. Further, there are a plurality of front end faces, and the same qualification check operation as in the past is quite troublesome. [Patent Document 1] JP-A-2003-311522 SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a drilling tool which is excellent in practical use even if it is drilled with a very small diameter. The tool is still not easily damaged. It does not need to be replaced frequently, and the shape is simple and easy to manufacture and inspect. The gist of the present invention will be described with reference to the accompanying drawings. A drilling tool is a drilling tool having one or a plurality of spiral chip discharge grooves 1' 2, characterized in that a flat front end face 5 having no ridge line intersecting the tool center axis is provided at the front end portion. In the drilling tool according to claim 1, the front end surface 5 is inclined at a predetermined inclination angle α with respect to the tool center axis. Further, in the drilling tool described in claim 1, the tool diameter is 〇.2 mm or less. Further, in the drilling tool described in claim 2, the tool diameter is 〇. 2 mm or less. Further, in the drilling tool according to any one of claims 1 to 4, the island portions 3 and 4 are provided between the plurality of chip discharge grooves 1 and 2, and the chip discharge grooves 1 and 2 and the front end surface 5 are provided. The plurality of intersecting ridge portions 6-200900183 6 and 7 are formed to have a foremost point on the long intersecting ridge portion 6, so that the intersecting ridge portion 6 exerts a cutting action. Further, in the drilling tool according to any one of claims 1 to 4, the island portions 3 and 4 are provided between the plurality of chip discharge grooves 1 and 2, and the island portions 3 and 4 and the front end surface 5 are formed. Among the plurality of intersecting ridge portions 8 and 9, the longest intersecting ridge portion 8 has a foremost point so that the intersecting ridge portion 8 exerts a cutting action. Further, in the drilling tool according to the fifth aspect of the invention, the inclination angle α of the distal end surface 5 to the tool center axis is set to a range of 0° to (90° to the torsion angle), and the drilling tool described in claim 6 is further provided. The inclination angle α of the distal end surface 5 to the tool center axis is set to a range of 0° to (90°-torsion angle). In the drilling tool described in claim 7, the inclination angle α is set to 10° to 30°. The range of °. Further, in the drilling tool described in claim 8, the inclination angle α is set in the range of 10° to 30°. According to the present invention, it is possible to provide a drilling tool which is excellent in practical use, and it is not easy to be broken even if it is a drilling tool having a very small diameter, and it is not necessary to perform frequent replacement, and the shape is simple and easy to manufacture and inspect. [Embodiment] A preferred embodiment of the present invention and its effects will be briefly described based on the drawings. The configuration of the present embodiment is such that a flat front end surface 5 having no ridge 200900183 line is provided at the tip end of the tool, and is different from a general drill (for example, a chisel tip is provided near the center of the work end, and is formed continuously in accordance with the chisel tip). Since the cutting resistance in the hole machining is almost always pushed, the bending stress generated by the external force in the direction perpendicular to the tool axis (the machining resistance in the hole machining) can be reduced, so that the breakage is less likely to occur. Further, the most prominent portion of the front end face 5 (and the intersecting ridge portion formed by the island portion or the cut-out groove) is gradually cut under the workpiece working surface, and is different from the above-described general drill bit because it is not easy to bite. At the beginning of the cutting, the tool will be slightly shaken, and the hole on the inlet side is enlarged while drilling, so that the hole diameter of the machined hole becomes closer to the inlet side, so that the base end side of the tool does not easily contact the inner wall of the machined hole. It can suppress the damage caused by the base end side of the tool contacting the inner wall of the machined hole. Further, the shape is simple, as long as the tip end portion of the tool in which the chip discharge groove is formed is removed at an appropriate position at an appropriate position, so that the desired cross-sectional shape and the desired inclination angle α are formed before the end face, again, due to the front end face 5 There is only one, and the left and right imbalances of the front end faces do not occur as with a tool having a plurality of faces, so that it is not necessary to check the balance of the left and right. Further, since a plurality of relief surfaces are not formed (the front end does not need to be checked for the width of the relief surface, the inspection can be simplified and improved. [Embodiment] The embodiment of the present invention will be described based on FIGS. 2 to 6 As shown in Fig. 2, the example of the drilling tool is provided with a first chip discharge groove 1 and a spiral second chip discharge groove 2, I-t ^ /. The greater the working degree, the easier the shape of the material is. Rotating and forming the island portions 3, 4 between the chip discharge grooves 1 and 2 at -8 - 200900183, the flat front end of the ridge line where there is no ridge line intersecting the center axis of the tool at the front end is represented by the symbols 6 and 7 The chip discharge grooves 1, 2 and the intersecting ridge portions formed on the front end surface, and the symbols 8 and 9 represent the intersection portions formed by the island portions 3, 4 and the front end. Specifically, the present embodiment applies the present invention to the maximum outer diameter of the tool diameter. 双. 〇 5 mm double-diameter drill with a very small diameter. However, it is not suitable for slot drills and can be applied to other drills such as single-slot drills. Also, it can be applied to tools with a tool diameter exceeding 〇.2mm. 〇 Then specify the parts. The front end face 5 is at a predetermined angle of inclination with respect to the tool center axis. The inclination angle α is preferably set to be equal to or higher than the angle of the tool axis at a right angle (0° or more) to 90°. - The torsion angle of the chip discharge groove. In the case of a larger angle than 90°-torsion angle (45° in this embodiment), that is, an angle larger than 90°-45°=45°, the tip of the tool tip is prone to a gap, which may be caused by the front end notch. The cutting ability results in a shortened life. Specifically, the front end face angle α of the present embodiment is set to 20. . In the front end surface 5 of the present embodiment, the tip end portion of the tool material is removed at an angle of a predetermined position in a state in which the cutter material is formed with the chips 1, 2, thereby forming a desired front end surface shape and a desired degree α. The shape of the front end surface 5 is roughly divided into the following two shapes. The first structure, as shown in Fig. 3, is a surface 5 provided on the chip discharge flat. 5 of the five shapes (the blade is limited to the angle that the tool α is not limited to the angle of the parallel direction, and becomes too poor. The inclined discharge groove is defined by the predetermined inclination angles I 1 , 2 -9 - 200900183 and the front end face 5 Among the plurality of intersecting ridge portions 6 and 7 formed, the intersecting ridge portion 6 has a foremost end point (the first contact with the workpiece causes the intersecting ridge portion 6 to exert a cutting action. The second structure 4 shows the island. Among the complex fork ridge portions 8 and 9 formed by the portions 3 and 4 and the front end surface 5, a point is formed on the long intersecting ridge portion 8 so that the intersecting ridge portion 8 exerts a cutting action. The angle α is set to 30°. In the present embodiment of Fig. 2, the first structure is adopted, and the front end point is not on the island portions 3 and 4 (outer circumference), and it is not easy to receive an external force in the direction perpendicular to the axis. In order to achieve a long life, it is stable in construction. Since the foremost point is on the islands 3 and 4 (outer circumference), the ability to cut is obtained, and good hole quality (hole position accuracy, hole internality) is obtained. With the above configuration, although there is no front end (chisel tip) or general If the blade having the leading end angle is concentrated, it is difficult to bite, but it is not easy to be subjected to the processing of the outer anterior end surface 5 in the direction perpendicular to the tool axis and the rake face of the chip discharge groove. In the case of the processing, it is not easy to cause damage to the front end. Further, the portion which is the most prominent portion of the front end surface 5 and the intersecting ridge portion 6 formed by the discharge of the chips abut against the processing surface, and the cutting is not easy to bite into the processing surface as described above. The tool will be slightly shaken while drilling the hole with a moderately enlarged diameter. Therefore, the hole diameter of the machined hole is larger on the inlet side, so the base end side of the tool is not easily contacted and processed at a longer point, such as the first intersection. At the front end of the first and fourth figures, the part of the force that lifts the thick and sharp portion of the cut wall surface by the second tool is formed by the green tool groove 1. Since the inlet side becomes the inner wall of the hole - 10 200900183, the cause can be suppressed. The base end side of the tool contacts the damage caused by the inner wall of the machined hole. The shape is simple, and the front end portion of the tool material on which the chip discharge groove is formed is removed at an appropriate angle at an appropriate position. Therefore, since it is easy to manufacture, since there is only one front end surface 5, the left-right imbalance of each front end surface does not generate like the tool which has a plurality of front end surfaces, and it is not necessary to carry out the balance check of the right and left. The clearance surface (front end surface) does not require the inspection of the width of the relief surface, which simplifies the inspection and improves the yield. Moreover, in the case of a tool with a tool diameter of less than 2 mm, the above effects can be significantly exerted. That is, in the case where the tool is a small diameter, the tip end of the tool is likely to be damaged at the initial stage of cutting, and the structure of the present embodiment can be used as much as possible to reduce the external force at the initial stage of the cutting. Therefore, it is useful in the present embodiment. Excellent drilling tools, even if it is made into a very small diameter drilling tool, it is not easy to break, no need to change frequently, and the shape is simple and easy to manufacture and inspect. Next, an experimental example for supporting the above effects will be described. As shown in Fig. 5, the tool life of both the tool (the embodiment) having one flat front end surface without the ridge line and the tool (the conventional example) shown in Fig. 1 is drilled on the PCB. As a result of comparing the number of hits, if the only flat surface having no ridge line on the front end surface is used, the tool life becomes about 2 times longer than the conventional structure having a plurality of front end faces (front end relief faces). . As shown in Fig. 6, the inclination angle of the flat front end surface where there is no ridge line is changed by 〇° (the embodiment of Fig. 5) to 45°, and the drilling of the PCB is compared with the tool life of -11 - 200900183 As a result, it was confirmed that the fracture life was longer than the conventional example in the range of 〇° to 45°. The range of ~30° is particularly long. [Simplified illustration of the drawing] Fig. 1 is a schematic illustration of a conventional example. Fig. 2 is a schematic explanatory view of the present embodiment. Fig. 3 is a schematic explanatory view for explaining the shape of the front end. Fig. 4 is a schematic explanatory view for explaining the shape of the front end. Fig. 5 is a comparison diagram of tool life for comparing the inclination angles of the front end faces of the front end faces of the present embodiment and the conventional example. [Main component symbol description] 1. 2: Chip discharge groove 3 4: island portion 5: front end surface 6' 7 : (formed by the chip discharge groove and the front end surface) intersecting ridge portions 8, 9: (formed by the island portion and the front end surface) intersecting ridge portion α: inclination angle -12 -