JP2000015512A - Coating twist drill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the chipping and break of a cutting edge by the biting and winding in of a chip by providing the tip of a margin in the specific % escape surface side of a drill edge diameter and making the process amount of a rake surface side to 1/2 or less of the escape surface side process amount. SOLUTION: By making the process amount of an escape surface side to 0.1-2% of a drill diameter, at less than 0.1% of the drill diameter, the processed amount is too small not to reduce the chipping and break of a cutting edge. At the retreating time beyond 2% of the drill diameter, as the strength is dropped instead of not taking a sufficient thickness on the rearside of a margin, it is made to 0.1-2% of the drill diameter. It is desiable that the process amount (a) of a rake surface side is 1/2 or less of the esacape surface side process amount (b) and when it is beyond 1/2, as there is such defect that the cutting edge itself is too big, such other problem that the cutting resistance is increased is generated. An arc shape is picked up as its connection way.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【産業上の利用分野】本願発明は、ツイストドリルの刃
先、特に先端刃と外周刃の交差する部分の切れ刃の改良
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a cutting edge of a twist drill, and more particularly to an improvement of a cutting edge at a crossing point between a tip blade and an outer peripheral blade.

【０００２】[0002]

【従来の技術】高速度工具鋼、超硬合金製ツイストドリ
ルにおける最大の課題は寿命の不安定さにある。ドリル
加工では様々な要因が挙げられているが、狭いスペース
を切り屑が移動し、排出される過程では多様な要因が考
えられる。切り屑に起因するものとしては噛み込みや巻
き込み等による切れ刃の損傷・欠損があり、また、切削
諸元からは、高速加工や高送り加工のような切り屑生成
が多い場合には振動等に起因する損傷、特に膜の損傷と
して剥離、脱落等がある。超硬合金製ツイストドリルで
は刃先、特に先端刃と外周刃の交叉する部分及び外周刃
の刃先は、シャープなエッジを有するため、その先端部
にネガホーニングや丸ホーニングが施されている。超硬
合金製では、特に切刃が高速度鋼製に比して脆いためホ
ーニングが行われ、例えば、特許２５０８５３９号では
先端刃のホーニングを中心側で狭く、外周側で広くする
ことが記載されている。また、マージン部は通常、ドリ
ル刃径と同じ円状に設けられるが、マージン部でも同様
なホーニングが行われているが、更に、マージン部で
は、マージン部の幅を先端側で狭くしたり（例えば、実
用新案第１８６４４６０号）、擦れを防止するため軸線
に対し直角方向に溝を設ける（例えば、特開平５−５０
３１３号）等の例がある。2. Description of the Related Art The biggest problem in twist drills made of high-speed tool steel and cemented carbide is instability of life. Various factors are mentioned in drilling, but various factors can be considered in a process in which chips move in a narrow space and are discharged. Chips are caused by damage or chipping of the cutting edge due to biting or entanglement, etc. In addition, from the cutting specifications, if there is a lot of chip generation such as high-speed machining or high feed machining, vibration etc. The peeling, falling off, etc. are the damages caused by the above, especially the damages of the film. In the twist drill made of cemented carbide, the edge of the cutting edge, in particular, the intersection between the tip blade and the outer peripheral edge and the edge of the outer peripheral edge have sharp edges, and thus the distal end is subjected to negative honing or round honing. In cemented carbide, honing is performed because the cutting edge is particularly brittle compared to high-speed steel.For example, in Japanese Patent No. 2,508,539, it is described that the honing of the tip blade is narrower at the center and wider at the outer periphery. ing. In addition, the margin portion is usually provided in the same circular shape as the drill bit diameter, but the same honing is performed in the margin portion. Further, in the margin portion, the width of the margin portion is narrowed on the distal end side ( For example, Japanese Utility Model No. 1864460), a groove is provided in a direction perpendicular to the axis to prevent rubbing (for example, see Japanese Patent Application Laid-Open No. H5-50).
No. 313).

【０００３】しかし、最近の被覆の改善により、特に耐
摩耗性に優れた皮膜、潤滑性に優れた皮膜をほどこした
ツイストドリル刃先の損傷状態を解析すると、チッビン
グ等を生じていない正常摩耗では、逃げ面側の摩耗によ
り寿命にいたり、すくい面側の摩耗は未だ皮膜が残存し
た状態である。特に、逃げ面側では、基体そのものが露
出し急速に摩耗が進行してしまう。また、チッピング、
欠損及び皮膜の剥離等の損傷を生じた場合では、チッピ
ングと同時に皮膜も取られてしまうため、正常摩耗時の
終期摩耗に相当する摩耗形態となり、チッピング部分が
急速に摩耗してしまうため短寿命なものとなってしまっ
ている。特に先端刃と外周刃の交叉する最も損傷する部
位では、偶発的にチッピング、欠損等を生じやすくより
大きなホーニングを施さなければならなかった。[0003] However, the analysis of the damage state of the cutting edge of a twist drill provided with a coating excellent in wear resistance and a coating excellent in lubrication due to recent improvement of the coating shows that in the case of normal wear in which no chipping or the like occurs, The service life has been reached due to the wear on the flank side, and the wear on the rake face side is a state in which the film still remains. In particular, on the flank side, the base itself is exposed and the wear proceeds rapidly. Also, chipping,
In the event of damage such as chipping or peeling of the coating, the coating is also removed at the same time as chipping, resulting in a wear form equivalent to the final wear during normal wear, and the chipping part wears quickly, resulting in a short life. It has become something. In particular, at the most damaged portion where the tip blade and the outer peripheral blade intersect, it is easy to accidentally cause chipping, breakage, and the like, and a larger honing must be performed.

【０００４】[0004]

【発明が解決しようとする課題】本願発明では、超硬合
金製ツイストドリルのみならず高速度鋼製ツイストドリ
ルにおいても、これらチッピング、欠損及び皮膜の剥離
等を生じにくい形状を検討した結果、切れ刃そのものを
後退させることにより、刃先に加わる切削荷重を刃の先
端部ではなく、やや下がった位置にシフトさせることに
より切れ刃の強度を高めた形状としたものである。According to the invention of the present application, not only in the twist drill made of cemented carbide but also in the twist drill made of high-speed steel, as a result of examining the shape which does not easily cause such chipping, chipping and peeling of the film, it was found that By retreating the blade itself, the cutting load applied to the blade tip is shifted to a slightly lowered position instead of the tip of the blade, thereby increasing the strength of the cutting blade.

【０００５】[0005]

【本発明の目的】従って、本願発明ではツイストドリル
の寿命をばらつかせるチッピング、欠損及び皮膜の剥離
等を改善するため切れ刃の強度を高めた形状とすること
により、安定したツイストドリルを提供することを目的
とする。SUMMARY OF THE INVENTION Accordingly, the present invention provides a stable twist drill by increasing the strength of the cutting edge in order to improve chipping, chipping, and peeling of the film, etc., which vary the life of the twist drill. The purpose is to do.

【０００６】[0006]

【課題を解決するための手段】そのため、高速度工具
鋼、超硬合金等の硬質材料からなる被覆を施したツイス
トドリルにおいて、マージン部の先端をドリル刃径の
０．１〜２％逃げ面側に設け、かつ、すくい面側の処理
量は逃げ面側処理量の１／２以下であることを特徴とす
るものである。また、被覆は硬質皮膜としてはＴｉＮ、
ＴｉＣＮ、ＴｉＡｌＮの膜やそれらの多層膜、潤滑性皮
膜は、ＭｏＳ等の潤滑性に優れた皮膜を前記硬質膜と多
層化したり、部分的に用いるものである。Therefore, in a twist drill coated with a hard material such as a high-speed tool steel or a cemented carbide, a tip of a margin portion has a flank of 0.1 to 2% of a diameter of a drill bit. And the amount of processing on the rake face is less than half the amount of processing on the flank side. The coating is TiN as a hard coating,
The TiCN and TiAlN films, their multilayer films, and the lubricating film are formed by multiplying or partially using a film having excellent lubricity such as MoS with the hard film.

【０００７】[0007]

【作用】具体的に従来例を図１に、本願発明の例を図２
を用いて説明する。図１より、刃先の強度の向上させる
には、従来の技術でも説明したように刃先処理として丸
ホーニングが行われている。丸ホーニングは刃の先端部
に丸味を設ける程度であり、その大きさはドリル径にも
よるが数ミクロン程度である。それに対して、図２よ
り、切れ刃となる稜線を更に後退させた位置にシフトさ
せたもので、そのため、すくい面側の処理量とマージン
（逃げ面）側処理量では、マージン（逃げ面）側処理量
が数倍処理することとなる。このマージン（逃げ面）側
処理量を大きく設けることにより、切れ刃そのものが処
理して、チッピング、欠損等の偶発的に生じる作用に対
して効果をそうする。FIG. 1 shows a conventional example, and FIG. 2 shows an example of the present invention.
This will be described with reference to FIG. As shown in FIG. 1, in order to improve the strength of the cutting edge, round honing is performed as a cutting edge treatment as described in the related art. The round honing is to provide a rounded edge at the tip of the blade, and its size is about several microns depending on the drill diameter. On the other hand, from FIG. 2, the ridge line serving as the cutting edge is shifted to a position further retracted. Therefore, in the processing amount on the rake face side and the processing amount on the margin (flank face) side, the margin (flank face) The side processing amount is processed several times. By providing a large amount of processing on the margin (flank surface) side, the cutting edge itself is processed, and the effect on accidental operations such as chipping and chipping is achieved.

【０００８】逃げ面側の処理量は、ドリル直径の０．１
〜２％としたのは、ドリル径の０．１％未満では、処理
させる量が小さすぎて従来のものと同程度の作用しかな
く、またドリル径の２％を超えて後退させると、マージ
ン部の後方に十分な肉厚がとれず、かえって強度を落と
すことになるためドリル直径の０．１〜２％とした。ま
た、すくい面側の処理量は、逃げ面側処理量の１／２以
下で良く、１／２を超えると、切刃処理量そのものが大
きくなりすぎる欠点があり、切削抵抗が増大してしまう
等他の問題が生じてしまう。また、その繋ぎ方は、円弧
状、直線状及び直線状の端部を丸めたもの等が挙げられ
る。以下、実施例に基づいて本発明例を具体的に説明す
る。The throughput on the flank side is 0.1 mm of the drill diameter.
When the drill diameter is less than 0.1%, the amount to be treated is too small and has only the same effect as that of the conventional drill. A sufficient wall thickness cannot be obtained behind the portion, and the strength is rather reduced, so that the diameter is set to 0.1 to 2% of the drill diameter. Further, the processing amount on the rake face side may be 以下 or less of the processing amount on the flank side, and if it exceeds １ ／, there is a disadvantage that the processing amount of the cutting edge itself becomes too large, and the cutting resistance increases. And other problems. In addition, examples of the connection method include an arc shape, a straight shape, and a shape obtained by rounding a straight end. Hereinafter, examples of the present invention will be specifically described based on examples.

【０００９】[0009]

【実施例】通常の粉末冶金法で、超微粒子超硬合金の素
材を製作し、２枚刃、ドリル径８ｍｍのツイストドリル
を製作した。その正面図を図３に、軸直角断面図を図４
に示す。次いで、外周刃に切れ刃処理として表１に示す
ような加工を行った。逃げ面側の処理量をａ、すくい面
側の処理量をｂ、及びその比（ｂ／ａ比）を表１に示す
ように製作し、試料を製作した。尚、超微粒子超硬合金
には、Ｃｏ量８％、皮膜はＴｉＡｌＮ皮膜を被覆した。EXAMPLE A material of ultrafine-grain cemented carbide was manufactured by a usual powder metallurgy method, and a two-edged twist drill having a drill diameter of 8 mm was manufactured. FIG. 3 is a front view thereof, and FIG.
Shown in Next, processing as shown in Table 1 was performed on the outer peripheral edge as a cutting edge treatment. The amount of processing on the flank side was a, the amount of processing on the rake side was b, and the ratio (b / a ratio) was as shown in Table 1, and samples were manufactured. The ultra-fine-grain cemented carbide was coated with a Co content of 8% and coated with a TiAlN film.

【００１０】[0010]

【表１】 [Table 1]

【００１１】表１に示す本発明例と比較例のドリルを用
いて、切削諸元として、被削材ＳＣＭ４４０（焼鈍材）
を用いて、切削速度１００ｍ／ｍｉｎ、送り速度１００
０ｍｍ／ｍｉｎで、穴深さ３２ｍｍ（ドリル径の３倍）
の穴加工を水溶性切削油を用いて行った。高速、高送り
の切削諸元では、切り屑の生成が多く、排出の際に偶発
的に噛んだり、巻き込んだり等によりドリルそのものに
損傷を与えることが多く、本試験では、切り屑等の形
状、排出等を観察しつつ、５０穴加工し、その損傷状態
をチッピング、欠損、皮膜の剥離等の程度により記載し
た。その結果も表１に併記する。Using the drills of the present invention and the comparative examples shown in Table 1, the work material SCM440 (annealed material) was used as the cutting data.
Using a cutting speed of 100 m / min and a feed speed of 100
0mm / min, hole depth 32mm (3 times the drill diameter)
Was performed using a water-soluble cutting oil. In high-speed, high-feed cutting specifications, chips are often generated, and the drill itself is often damaged by accidental biting or entanglement at the time of discharge. While observing the discharge and the like, 50 holes were machined, and the damage state was described by the degree of chipping, chipping, peeling of the film, and the like. The results are also shown in Table 1.

【００１２】表１より、刃先を後退させた本発明例で
は、切れ刃そのものが十分に後退しているため、切れ刃
の強度が高く、また、皮膜の剥離も生ずることなく５０
穴の加工が行えた。更に、切り屑排出性では、本発明例
１〜３のツイストドリルでは、切り屑形態も遷移折断型
で、排出もスムーズであった。また、本発明例４、５の
様に逃げ面側の処理量に比してすくい面側を小さな処理
量としたものは、最も安定した切削で、送り速度１００
０ｍｍ／ｍｉｎの本試験では切り屑排出にも問題なく行
うことができた。また、更に本発明例６〜８の様に逃げ
面側の処理量を大きくした例では、やや切削抵抗は増え
るものの屑排出にも問題なく行うことができた。次に、
従来例の比較例９では、処理量が小さいため、加工初期
にチッピングが生じ、５０穴加工では欠損を生じてい
た。また、やや大きくした比較例１０ではすくい、逃げ
面とも大きな処理量としたため、やや切削抵抗は増える
ものの、高送りの本試験ではやや振動が生じてチッピン
グした。比較例１１、１２ではすくい面側の処理量が大
きいため、切削抵抗は小さいが、偶発的に生じる噛み込
みや切り屑の巻き込み等による微小なチッピングを多数
生じていた。According to Table 1, in the example of the present invention in which the cutting edge is retracted, the cutting edge itself is sufficiently retracted, so that the strength of the cutting edge is high, and there is no peeling of the film.
The hole was processed. Further, with respect to the chip dischargeability, in the twist drills of Examples 1 to 3 of the present invention, the chip form was also a transition breaking type and the discharge was smooth. Also, as in the present invention examples 4 and 5, the rake face having a smaller processing amount than the flank processing amount was the most stable cutting, and the feed rate was 100%.
In this test at 0 mm / min, chips could be discharged without any problem. Further, in the example in which the processing amount on the flank side was increased as in Examples 6 to 8 of the present invention, although the cutting resistance was slightly increased, it was possible to discharge the debris without any problem. next,
In Comparative Example 9 of the conventional example, since the processing amount was small, chipping occurred in the initial stage of processing, and loss occurred in 50-hole processing. Further, in Comparative Example 10 where the size was slightly increased, since the processing amount was large for both the rake face and the flank, the cutting resistance was slightly increased, but in the high feed test, slight vibration occurred and chipping occurred. In Comparative Examples 11 and 12, since the processing amount on the rake face side was large, the cutting resistance was small, but a large number of minute chippings occurred due to accidental biting or chip entrapment.

【００１３】[0013]

【発明の効果】本願発明のツイストドリルでは、逃げ面
側に刃先を移動させることにより、ツイストドリルにあ
りがちな寿命のバラツキの主な原因である切り屑等の噛
み込みや巻き込みによる切れ刃のチッピング、欠け等を
低減させることができ、高速・高送り等の切り屑を大量
に生成・排出する切削において安定した性能を示す。According to the twist drill of the present invention, by moving the cutting edge to the flank side, chipping of the cutting edge due to biting or entanglement of chips or the like, which is a main cause of the variation in the life that is common in twist drills. , Chipping, etc., can be reduced, and shows stable performance in cutting that generates and discharges a large amount of chips at high speed and high feed rate.

【図面の簡単な説明】[Brief description of the drawings]

【図１】図１は、従来の刃先の拡大した断面図を示す。FIG. 1 is an enlarged sectional view of a conventional cutting edge.

【図２】図２は、本発明例の刃先の拡大した断面図を示
す。FIG. 2 is an enlarged cross-sectional view of a cutting edge according to an example of the present invention.

【図３】図３は、本発明例の正面図を示す。FIG. 3 shows a front view of an example of the present invention.

【図４】図４は、図３の断面図を示す。FIG. 4 shows a cross-sectional view of FIG.

【符号の簡単な説明】[Brief description of reference numerals]

１ ツイストドリル本体 ２ 溝幅 ａ 逃げ面側処理量 ｂ すくい面側処理量 1 twist drill body 2 groove width a flank side processing amount b rake surface side processing amount

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】 高速度工具鋼、超硬合金等の硬質材料か
らなる被覆を施したツイストドリルにおいて、マージン
部の先端をドリル刃径の０．１〜２％逃げ面側に設け、
かつ、すくい面側の処理量は逃げ面側処理量の１／２以
下であることを特徴とするコーティングツイストドリ
ル。In a twist drill coated with a hard material such as high-speed tool steel or cemented carbide, a tip of a margin part is provided on a flank side of 0.1 to 2% of a drill blade diameter.
A coating twist drill characterized in that the processing amount on the rake face side is not more than half of the processing amount on the flank side. 【請求項２】 請求項１記載のコーティングツイストド
リルにおいて、前記被覆が硬質皮膜及び／又は潤滑製皮
膜からなることを特徴とするコーティングツイストドリ
ル。2. The coating twist drill according to claim 1, wherein the coating comprises a hard coating and / or a lubricating coating.