JP2013176817A - Drill made of diamond-coated cemented carbide having excellent wear resistance - Google Patents
Drill made of diamond-coated cemented carbide having excellent wear resistance Download PDFInfo
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この発明は、ＣＦＲＰとＡｌの重ね合わせ穿孔などにおいて、耐チッピング性に優れるばかりか、長期の使用に亘ってすぐれた耐摩耗性を発揮するダイヤモンド被覆超硬合金製ドリルに関する。 The present invention relates to a diamond-coated cemented carbide drill that not only has excellent chipping resistance, but also exhibits excellent wear resistance over a long period of use, such as in the overlap drilling of CFRP and Al.
従来、炭化タングステン基（ＷＣ基）超硬合金からなる基体に、ダイヤモンド膜を被覆したダイヤモンド被覆超硬合金製ドリルが知られているが、従来のダイヤモンド被覆超硬合金製ドリルにおいては、耐溶着性、耐摩耗性が十分でないため、これを改善するために種々の提案がなされている。 Conventionally, a diamond-coated cemented carbide drill in which a diamond film is coated on a base made of a tungsten carbide group (WC-based) cemented carbide is known. Since the property and wear resistance are not sufficient, various proposals have been made to improve this.
例えば、特許文献１に示すように、ダイヤモンド被覆切削工具において、切れ刃部の逃げ面におけるダイヤモンド層の平均層厚を、すくい面のダイヤモンド層のそれよりも厚くすることによって、工具寿命を延ばすとともに、難削材に対する加工品位を高めることが提案されている。 For example, as shown in Patent Document 1, in a diamond-coated cutting tool, by increasing the average layer thickness of the diamond layer on the flank face of the cutting edge portion than that of the diamond layer on the rake face, the tool life is extended. It has been proposed to improve the processing quality for difficult-to-cut materials.
また、例えば、特許文献２に示すように、人工ダイヤモンド被覆超硬合金製スローアウエイ切削チップにおいて、ダイヤモンド被覆層の厚さを、切刃のすくい面における角部を標準厚さとし、少なくとも切粉当接部分を含む他の部分を標準厚さより相対的に肉厚とすることによって、人工ダイヤモンド被覆層の剥離を抑制し、工具の長寿命化を図ることが提案されている。 In addition, for example, as shown in Patent Document 2, in a throwaway cutting tip made of an artificial diamond-coated cemented carbide, the thickness of the diamond coating layer is the standard thickness at the corner of the rake face of the cutting blade, and at least the chip application It has been proposed to increase the life of the tool by suppressing the peeling of the artificial diamond coating layer by making the other parts including the contact part relatively thicker than the standard thickness.
近年の切削加工の技術分野における省力化および省エネ化、さらに低コスト化に対する要求は強く、また、切削ドリルの汎用性も求められてきているが、従来のダイヤモンド被覆超硬合金製ドリル（以下、単にダイヤモンド被覆ドリルという）を、ＣＦＲＰ単体、あるいは、ＣＦＲＰとＡｌ合金の複合材等の難削材のドリル加工に供した場合には、摩耗進行が早く、また、チゼルエッジ部での溶着発生等により、穴精度の劣化や切れ刃が欠損する、などの問題が生じていた。
また、例えば、上記特許文献1に示されるダイヤモンド被覆ドリルにおいては、逃げ面側のダイヤモンド被覆厚を厚くし、すくい面側の被覆厚を薄くしているため、エッジの鋭利さの確保という点での利点はあるものの、チゼルエッジ部の層厚が厚いために、その部分において溶着を発生し、穴精度確保が不十分であり、これが問題となっていた。
そこで、この発明は、エッジ部の鋭利さを保ち、溶着の発生を抑制し、穴精度確保や切れ刃の耐欠損性に優れたダイヤモンド被覆ドリルを提供することを目的とする。
In recent years, there has been a strong demand for labor saving and energy saving in the technical field of cutting work, and further cost reduction, and the versatility of cutting drills has also been demanded. When a diamond-coated drill is used for drilling difficult-to-cut materials such as CFRP alone or a composite material of CFRP and Al alloy, the wear progresses quickly, and welding occurs at the chisel edge. There have been problems such as deterioration of hole accuracy and missing cutting edges.
Further, for example, in the diamond-coated drill shown in Patent Document 1, the diamond coating thickness on the flank side is increased and the coating thickness on the rake surface side is reduced, so that the sharpness of the edge is ensured. However, since the thickness of the chisel edge portion is thick, welding occurs at that portion, and the hole accuracy is not sufficiently secured, which is a problem.
Therefore, an object of the present invention is to provide a diamond-coated drill that maintains the sharpness of the edge portion, suppresses the occurrence of welding, and ensures excellent hole accuracy and chipping resistance of the cutting edge.
本発明者らは、ＣＦＲＰ単体、あるいは、ＣＦＲＰとＡｌ合金の複合材等の難削材のドリル加工において、切れ刃の欠損やドリルの折損を生じにくくするとともに、長期の使用に亘って、すぐれた耐摩耗性を発揮するダイヤモンド被覆工具を提供すべく鋭意検討を重ねたところ、次のような知見を得た。 In the drilling of difficult-to-cut materials such as CFRP alone or a composite material of CFRP and Al alloy, the present inventors make it difficult to cause breakage of the cutting edge and breakage of the drill, and excellent for long-term use. As a result of intensive studies to provide a diamond-coated tool that exhibits excellent wear resistance, the following findings were obtained.
即ち、熱フィラメントＣＶＤ装置内でダイヤモンドを成膜するにあたって、熱フィラメントをドリル外周刃に出来るだけ近づけ、ドリル本体はシャンク部を冷却することで、ドリル基体（ＷＣ超硬合金）には温度差が生じ、ダイヤモンド成膜のための活性種（メチルラジカル、原子状水素）の供給量の差を大きくすることができる。
それにより、チゼルエッジ部と切刃外周部とのダイヤモンド膜の膜厚差を大きくすることができ、さらに、成膜されるダイヤモンドの膜質差を大きくすることができる。
本発明者らは、上記の方法でダイヤモンドを成膜することによって、チゼルエッジ部ではダイヤモンドの膜厚を薄くするとともに、ダイヤモンドの結晶性を低下せしめることによって、被削材との溶着発生を抑制し得るとともに、チゼルエッジ部の鋭利さを保つことができるため、アルミ合金の切削においても食いつきよく加工することが可能であることを見出した。
一方、切刃外周部においては、ダイヤモンドの膜厚を厚くし、しかも、結晶性を高くすることができるから、耐摩耗性を向上し得ることを見出したのである。
つまり、チゼルエッジ部と切刃外周部のダイヤモンド膜の膜厚、結晶性を異ならしめることによって、穴位置精度を確保すると同時に、長期の使用に亘ってすぐれた耐摩耗性を発揮するダイヤモンド被覆ドリルを得られることを見出したのである。
That is, when forming a diamond film in a hot filament CVD apparatus, the thermal filament is brought as close as possible to the outer peripheral edge of the drill, the drill body cools the shank portion, and the temperature difference between the drill base (WC cemented carbide) As a result, the difference in supply amount of active species (methyl radicals, atomic hydrogen) for diamond film formation can be increased.
Thereby, the difference in film thickness of the diamond film between the chisel edge part and the outer peripheral part of the cutting edge can be increased, and further, the difference in film quality of the diamond film to be formed can be increased.
The inventors reduced the film thickness of the diamond at the chisel edge by reducing the film thickness of the diamond by reducing the crystallinity of the diamond by depositing the diamond by the above method. In addition, it has been found that the sharpness of the chisel edge portion can be maintained, so that it can be processed with great bite even when cutting an aluminum alloy.
On the other hand, in the outer peripheral portion of the cutting edge, it has been found that the wear resistance can be improved because the film thickness of diamond can be increased and the crystallinity can be increased.
In other words, by changing the film thickness and crystallinity of the diamond film on the chisel edge and the outer periphery of the cutting edge, a diamond-coated drill that ensures excellent hole position accuracy and at the same time exhibits excellent wear resistance over a long period of use. I found out that I could get it.
本発明は、上記知見に基づいてなされたものであって、
「（１） 炭化タングステンとコバルトを主成分とし、かつ、３〜１５質量％のコバルトを含有する炭化タングステン基超硬合金をドリル基体とし、該ドリル基体の先端の外周部上に平均膜厚５〜３０μｍのダイヤモンド膜を被覆形成したダイヤモンド被覆超硬合金製ドリルにおいて、
上記ドリルの切刃外周部の膜厚をｈ１とし、チゼルエッジ部の膜厚をｈ２とした時に、ｈ１／ｈ２の値が１．２以上２．０以下であることを特徴とするダイヤモンド被覆超硬合金製ドリル。
（２） 上記ドリルの切刃外周部とチゼルエッジ部をラマン分光測定した場合、ダイヤモンド由来の１３３３ｃｍ−１を中心とするピークの半価幅を、それぞれｗ１、ｗ２とした時に、ｗ２の値が１５ｃｍ-１〜２５ｃｍ−１であり、かつｗ１／ｗ２の値が０．５以上０．９以下であることを特徴とする前記（１）に記載のダイヤモンド被覆超硬合金製ドリル。
（３） 上記ドリルの切刃外周部とチゼルエッジ部の圧縮残留応力の値を、それぞれσ１、σ２とした時に、σ２の値が１．８ＧＰａ以下であり、かつσ２／σ１の値が０．６以上０．９以下であることを特徴とする前記（１）または（２）に記載のダイヤモンド被覆超硬合金製ドリル。」
を特徴とするものである。
The present invention has been made based on the above findings,
“(1) Tungsten carbide-based cemented carbide containing tungsten carbide and cobalt as main components and containing 3 to 15% by mass of cobalt is used as a drill base, and an average film thickness of 5 is formed on the outer periphery of the tip of the drill base. In a diamond-coated cemented carbide drill coated with a diamond film of ˜30 μm,
Diamond coated carbide characterized in that the value of h1 / h2 is 1.2 or more and 2.0 or less when the film thickness of the outer peripheral part of the cutting edge of the drill is h1 and the film thickness of the chisel edge part is h2. Alloy drill.
(2) In the case of Raman spectroscopic measurement of the outer peripheral part and chisel edge part of the above-mentioned drill, the value of w2 is 15 cm when the half-value width of the peak centered at 1333 cm −1 derived from diamond is w1 and w2, respectively. The diamond-coated cemented carbide drill according to (1), wherein the drill is made of −1 to 25 cm −1 and w1 / w2 is 0.5 or more and 0.9 or less.
(3) When the values of the compressive residual stress at the outer peripheral portion of the cutting edge and the chisel edge portion of the drill are σ1 and σ2, respectively, the value of σ2 is 1.8 GPa or less and the value of σ2 / σ1 is 0.6. The drill made of a diamond-coated cemented carbide according to the above (1) or (2), wherein the drill is 0.9 or less. "
It is characterized by.
以下、本発明について詳細に説明する。 Hereinafter, the present invention will be described in detail.
本発明のダイヤモンド被覆ドリルのドリル基体としては、硬質相成分としての炭化タングステン（ＷＣで示す）と結合相成分としてのＣｏを少なくとも含有し、かつ、Ｃｏ含有量は３〜１５質量％であるＷＣ基超硬合金を使用する。
Ｃｏ成分には、結合相を形成して基体の強度および靭性を向上させる作用があるが、ＷＣ基超硬合金中のＣｏ含有量が３質量％未満では、特に靭性の向上が望めず、一方、Ｃｏ含有量が１５質量％を越えると、塑性変形が起り易くなって、偏摩耗の進行が促進されるようになることから、ＷＣ基超硬合金中のＣｏ含有量は３〜１５質量％と定める。
As a drill base of the diamond-coated drill of the present invention, WC having at least tungsten carbide (indicated by WC) as a hard phase component and Co as a binder phase component, and having a Co content of 3 to 15% by mass. Use base cemented carbide.
The Co component has an effect of improving the strength and toughness of the substrate by forming a binder phase. However, when the Co content in the WC-based cemented carbide is less than 3% by mass, no improvement in toughness can be expected. When the Co content exceeds 15% by mass, plastic deformation easily occurs and the progress of uneven wear is promoted. Therefore, the Co content in the WC-based cemented carbide is 3 to 15% by mass. It is determined.
また、基体表面に被覆するダイヤモンド膜は、その厚さが５μｍ未満では、長期の使用に亘って十分な耐摩耗性を発揮することができず、一方、ダイヤモンド膜厚が３０μｍを超えると、チッピング、欠損、剥離が発生しやすくなることから、ダイヤモンド膜の膜厚は、５〜３０μｍと定めた。 Further, if the thickness of the diamond film coated on the substrate surface is less than 5 μm, sufficient wear resistance cannot be exhibited over a long period of use, whereas if the diamond film thickness exceeds 30 μm, chipping is performed. Therefore, the film thickness of the diamond film was determined to be 5 to 30 μm.
本発明のダイヤモンド被覆ドリルでは、図1に示すように、ドリルの切刃外周部の膜厚をｈ１とし、チゼルエッジ部の膜厚をｈ２とした時に、ｈ１／ｈ２の値が１．２以上２．０以下となるようにダイヤモンドの被覆厚を定めたが、その理由の一つは、チゼルエッジ部の膜厚を薄くすることによって、チゼルエッジ部の鋭利さを保持するということにあり、また、切刃外周部の膜厚を相対的に厚くすることにより、耐摩耗性を維持するということにある。
即ち、後記する成膜法によって、チゼルエッジ部ではダイヤモンドの膜厚を相対的に薄く成膜することによって、チゼルエッジ部の鋭利さを保つことができるため、アルミ合金切削時の食いつきを確保することができる。
ただ、ｈ１／ｈ２の値が１．２未満の場合には、アルミ合金切削時の食いつきの確保は可能となる場合はあるが、その反面、工具寿命延長効果が小さくなり、また、ｈ１／ｈ２の値が２．０を超えると、チゼルエッジ部付近の切れ刃の摩耗量が大きくなり早期に寿命に達することから、ｈ１／ｈ２の値は、１．２以上２．０以下と定めた。
切刃外周部、チゼルエッジ部におけるダイヤモンド膜厚の測定は、切れ刃部を切断してＳＥＭ観察を行い、対象部分の膜厚の３点測定を行い、その平均値をそれぞれの膜厚とする。
なお、本発明でいう「チゼルエッジ部」とは、「ドリルの中央先端部から１００μｍの範囲内」を指し、「切刃外周部」とは、「ドリルの外周部の肩部から１００μｍの範囲内」を指す。
In the diamond-coated drill of the present invention, as shown in FIG. 1, when the thickness of the outer peripheral portion of the cutting edge of the drill is h1, and the thickness of the chisel edge portion is h2, the value of h1 / h2 is 1.2 or more and 2 The diamond coating thickness was determined to be less than or equal to 0.0. One reason for this is that the sharpness of the chisel edge is maintained by reducing the thickness of the chisel edge. The wear resistance is maintained by relatively increasing the film thickness of the blade outer peripheral portion.
In other words, the sharpness of the chisel edge portion can be maintained by forming a relatively thin diamond film at the chisel edge portion by the film forming method described later, so that the biting at the time of cutting the aluminum alloy can be ensured. it can.
However, when the value of h1 / h2 is less than 1.2, it may be possible to ensure the biting during the cutting of the aluminum alloy, but on the other hand, the effect of extending the tool life is reduced, and h1 / h2 If the value exceeds 2.0, the amount of wear of the cutting edge near the chisel edge increases and the life is reached early. Therefore, the value of h1 / h2 is determined to be 1.2 or more and 2.0 or less.
For the measurement of the diamond film thickness at the outer peripheral part of the cutting edge and the chisel edge part, the cutting edge part is cut and SEM observation is performed, the three-point measurement of the film thickness of the target part is performed, and the average value is taken as each film thickness.
In the present invention, the “chisel edge portion” refers to “within a range of 100 μm from the center tip portion of the drill”, and the “cutting blade outer peripheral portion” refers to “within a range of 100 μm from the shoulder portion of the outer peripheral portion of the drill. ".
本発明のダイヤモンド被覆ドリルでは、ドリルの切刃外周部とチゼルエッジ部をＡｒレーザーによるラマン分光測定した場合、ダイヤモンド由来の１３３３ｃｍ−１を中心とするピークの半価幅を、それぞれｗ１、ｗ２とした時に、ｗ２の値が１５ｃｍ-１以上２５ｃｍ-１以下であり、かつｗ１／ｗ２の値が０．５以上０．９以下であることが望ましい。
これは、チゼルエッジ部のダイヤモンド膜の結晶性をある程度低下させておくこととと、切刃外周部の結晶性に比して相対的に低下させておくことにより、チゼルエッジ部における被削材との溶着発生を抑制するとともに、切刃外周部においては、耐摩耗性を確保するという理由による。
即ち、ｗ２の値が１５ｃｍ-１未満の場合には、被削材との溶着発生抑制効果が少なくなり、一方、２５ｃｍ-１を超える場合には、耐摩耗性低下が顕著となるため、ｗ２の値は１５ｃｍ-１以上２５ｃｍ-１以下であることが望ましい。また、ｗ１／ｗ２の値が０．５未満の場合には、チゼルエッジ部付近における耐摩耗性低下が顕著となり、一方、ｗ１／ｗ２の値が０．９を超える場合には、被削材との溶着発生抑制効果が少なくなるため、ｗ１／ｗ２の値は０．５以上０．９以下であることが望ましい。
このようなｗ２の値およびｗ１／ｗ２の値は、ダイヤモンド膜の後記する成膜法によって、形成することができる。
In the diamond-coated drill of the present invention, when Raman spectroscopic measurement was performed on the outer peripheral portion and the chisel edge portion of the drill with an Ar laser, the half-value widths of the peaks centered at 1333 cm −1 derived from diamond were w1 and w2, respectively. Sometimes, it is desirable that the value of w2 is 15 cm −1 or more and 25 cm −1 or less and the value of w1 / w2 is 0.5 or more and 0.9 or less.
This is because the crystallinity of the diamond film at the chisel edge is reduced to some extent and is relatively lower than the crystallinity at the outer periphery of the cutting edge. This is because the occurrence of welding is suppressed and wear resistance is ensured at the outer peripheral portion of the cutting edge.
That is, when the value of w2 is less than 15 cm −1 , the effect of suppressing the occurrence of welding with the work material is reduced. On the other hand, when it exceeds 25 cm −1 , the wear resistance is significantly reduced. The value of is desirably 15 cm −1 or more and 25 cm −1 or less. In addition, when the value of w1 / w2 is less than 0.5, the wear resistance decrease in the vicinity of the chisel edge portion becomes significant, while when the value of w1 / w2 exceeds 0.9, the work material is Therefore, the value of w1 / w2 is preferably 0.5 or more and 0.9 or less.
Such a value of w2 and a value of w1 / w2 can be formed by a film forming method described later.
本発明のダイヤモンド被覆ドリルでは、切刃外周部とチゼルエッジ部の圧縮残留応力の値を、それぞれσ１、σ２とした時に、σ２の値が１．８ＧＰａ以下であり、かつσ２／σ１の値を０．６以上０．９以下とすることが好ましい。
これは、σ２の値が１．８ＧＰａを超えると被削材の溶着等に起因して膜剥離などを発生しやすくなるためである。σ２の下限値は技術的な意味からは特に設定はしないが、上記のｗ２の値が２５ｃｍ−１程度である場合、製法上、１．２〜１．４ＧＰａあたりが下限値となる。また、σ２／σ１の値が０．６未満であるとチゼルエッジ部における摩耗が進行し易く、一方、この値が０．９を超えると、被削材の溶着等に起因するチッピングを発生しやすくなるからである。
なお、切刃外周部、チゼルエッジ部におけるダイヤモンド膜の圧縮残留応力は、Ｃｏを管球とするＸ線回折による２θ−ｓｉｎ２φ法によって求めることができる。
In the diamond-coated drill of the present invention, when the compressive residual stress values at the outer peripheral portion of the cutting edge and the chisel edge portion are σ1 and σ2, respectively, the value of σ2 is 1.8 GPa or less and the value of σ2 / σ1 is 0. It is preferable to set it to 6 or more and 0.9 or less.
This is because if the value of σ2 exceeds 1.8 GPa, film peeling or the like is likely to occur due to welding of the work material. The lower limit of σ2 is not particularly set from the technical point of view, but when the value of w2 is about 25 cm −1 , the lower limit is about 1.2 to 1.4 GPa in terms of manufacturing method. Further, when the value of σ2 / σ1 is less than 0.6, wear at the chisel edge portion is likely to proceed, whereas when this value exceeds 0.9, chipping due to welding of the work material is likely to occur. Because it becomes.
Incidentally, the cutting edge outer peripheral portion, the residual compressive stress in the diamond film in the chisel edge portion can be determined by the 2θ-sin 2 φ method using X-ray diffraction that the Co and bulb.
本発明のダイヤモンド被覆ドリルは、例えば、以下の方法によって製造することができる。
まず、ＷＣとＣｏを主成分とし、Ｃｏを３〜１５質量％含有する超硬合金焼結体からなるＷＣ基超硬合金ドリル基体を作製した後、該超硬合金ドリル基体の表面近傍のＣｏを化学的なエッチング（硫酸＋過酸化水素＋水）によって除去し、その後、熱フィラメントＣＶＤ装置に装入し、ドリル基体のシャンク部を水冷治具で冷却支持し、フィラメントをドリル外周部の近傍にセットし、フィラメントの位置を成膜するダイヤモンドの膜厚に応じて調整しながらダイヤモンドを成膜することによって製造することができる。
なお、ドリル径によってフィラメントの位置を調節することも必要であり、例えば、ドリル径が６ｍｍより細い場合には、フィラメント位置を下側に移動させ、また、ドリル径が１０ｍｍより太い場合には、フィラメント位置を上側に移動させて、所望の膜厚になるように調整することが必要である。
このようなダイヤモンド膜の成膜法により、ドリルの切刃外周部の膜厚とチゼルエッジ部の膜厚の比の値ｈ１／ｈ２が１．２以上２．０以下、また、ラマン分光測定における１３３３ｃｍ−１を中心とするピークの半価幅の比の値ｗ１／ｗ２が０．５以上０．９以下、さらに、圧縮残留応力の比の値σ２／σ１が０．６以上０．９以下である本発明のダイヤモンド被覆ドリルを製造することができる。
The diamond-coated drill of the present invention can be manufactured, for example, by the following method.
First, a WC-based cemented carbide drill base composed of a cemented carbide sintered body containing WC and Co as main components and containing 3 to 15% by mass of Co is manufactured, and then Co in the vicinity of the surface of the cemented carbide drill base is prepared. Is removed by chemical etching (sulfuric acid + hydrogen peroxide + water), and then inserted into a hot filament CVD device, the shank part of the drill base is cooled and supported by a water cooling jig, and the filament is near the outer periphery of the drill. The film can be manufactured by forming a diamond film while adjusting the position of the filament according to the film thickness of the diamond film to be formed.
It is also necessary to adjust the position of the filament according to the drill diameter. For example, when the drill diameter is smaller than 6 mm, the filament position is moved downward, and when the drill diameter is larger than 10 mm, It is necessary to adjust the filament position by moving it upward so that the desired film thickness is obtained.
By such a diamond film formation method, the ratio h1 / h2 of the film thickness of the outer peripheral portion of the cutting edge of the drill to the thickness of the chisel edge portion is 1.2 or more and 2.0 or less, and 1333 cm in Raman spectroscopic measurement. The ratio value w1 / w2 of the half width of the peak centered at −1 is 0.5 or more and 0.9 or less, and the ratio value σ2 / σ1 of the compressive residual stress is 0.6 or more and 0.9 or less. Certain diamond coated drills of the present invention can be manufactured.
本発明のダイヤモンド被覆ドリルは、切刃外周部に比して、チゼルエッジ部のダイヤモンドの膜厚を相対的に薄くするとともに、ダイヤモンドの結晶性を低下せしめ、さらに、圧縮残留応力を適正な範囲に保つことによって、被削材との溶着発生を抑制し得るとともに、チゼルエッジ部の鋭利さを保つことができるため、穴位置精度を確保し得ることができるとともに、長期の使用に亘って、すぐれた耐摩耗性を発揮するのである。 The diamond-coated drill of the present invention has a relatively thin diamond film thickness at the chisel edge portion as compared with the outer peripheral portion of the cutting edge, lowers the crystallinity of the diamond, and further reduces the compressive residual stress to an appropriate range. By maintaining, the occurrence of welding with the work material can be suppressed, and the sharpness of the chisel edge can be maintained, so that the hole position accuracy can be ensured and excellent over a long period of use. It exhibits wear resistance.
つぎに、本発明のダイヤモンド被覆ドリルについて、実施例により具体的に説明する。 Next, the diamond-coated drill of the present invention will be specifically described with reference to examples.
（ａ） 原料粉末として、いずれも０．５〜３μｍの範囲内の所定の平均粒径を有するＷＣ粉末、Ｃｏ粉末、Ｃｒ３Ｃ２粉末、ＶＣ粉末、ＴａＣ粉末、ＮｂＣ粉末、ＴｉＣ粉末およびＺｒＣ粉末を、表１に示される割合に配合し、さらにバインダーと溶剤を加えてアセトン中で２４時間ボールミル混合し、減圧乾燥した後、いずれも１００ＭＰａの圧力でプレス成形して、直径が１０ｍｍの丸棒圧粉体とし、これらの丸棒圧粉体を、１Ｐａの真空雰囲気中、１３８０〜１４５０℃の温度で１〜２ 時間保持後、炉冷の条件で焼結することにより、ＷＣ基超硬合金焼結体１〜５を製造した。
ついで、上記ＷＣ基超硬合金焼結体１〜５を、溝形成部の外径寸法が８ｍｍとなるように研削加工することにより、ＷＣ基超硬合金製ドリル基体（以下、単に「ドリル基体」という）１〜５を製造した。
(A) WC powder, Co powder, Cr 3 C 2 powder, VC powder, TaC powder, NbC powder, TiC powder, and ZrC, all having a predetermined average particle size in the range of 0.5 to 3 μm as raw material powder The powder was blended in the proportions shown in Table 1, and after further adding a binder and a solvent, mixed in a ball mill for 24 hours in acetone, dried under reduced pressure, and then press-molded at a pressure of 100 MPa. WC-based cemented carbide is obtained by sintering in a 1 Pa vacuum atmosphere at a temperature of 1380 to 1450 ° C. for 1 to 2 hours and then sintering under furnace cooling conditions. Alloy sintered bodies 1 to 5 were produced.
Next, by grinding the WC-based cemented carbide sintered bodies 1 to 5 so that the outer diameter of the groove forming portion is 8 mm, a WC-based cemented carbide drill base (hereinafter simply referred to as “drill base”). 1) to 5).
（ｂ） ついで、上記ドリル基体１〜５を、硫酸と過酸化水素と水を１：１：１００（容積比）で混合したエッチング液に２〜４秒浸漬して、ドリル基体１〜５の表面近傍のＣｏを数ミクロンの深さまでエッチングで除去する。 (B) Next, the drill bases 1 to 5 are immersed in an etching solution in which sulfuric acid, hydrogen peroxide, and water are mixed at 1: 1: 100 (volume ratio) for 2 to 4 seconds. Co near the surface is removed by etching to a depth of several microns.
（ｃ） ついで、このドリル基体１〜５を、熱フィラメントＣＶＤ装置に装入し、ドリル基体をシャンク部で水冷治具により冷却支持し、フィラメントをドリルの外周部から５ｍｍの位置にセットし、フィラメントに電流を流して２２００℃の温度とし、装置内に水素ガスとメタンガスを導入し、該雰囲気ガス中でドリル基体１〜５にダイヤモンド膜を成膜することにより、表２に示す本発明のダイヤモンド被覆ＷＣ基超硬合金製ドリル（以下、単に、「本発明ドリル」という）１〜１０を製造した。 (C) Next, the drill bases 1 to 5 are inserted into a hot filament CVD apparatus, the drill base is cooled and supported by a water cooling jig at the shank, and the filament is set at a position 5 mm from the outer periphery of the drill. An electric current is passed through the filament to a temperature of 2200 ° C., hydrogen gas and methane gas are introduced into the apparatus, and a diamond film is formed on the drill bases 1 to 5 in the atmospheric gas, whereby the present invention shown in Table 2 is formed. Diamond-coated WC-based cemented carbide drills (hereinafter simply referred to as “the drills of the present invention”) 1 to 10 were produced.
比較のため、本発明ドリル１〜１０の上記製造工程における工程（ａ）〜（ｃ）により、表３に示す比較例のダイヤモンド被覆ＷＣ基超硬合金製ドリル（以下、単に、「比較例ドリル」という）１〜１０を製造した。
なお、比較例ドリル１〜１０の製法においては、ドリル基体を冷却する機構がないこと、そのため、ドリルとフィラメント間の距離は基板温度を適正に保つために、１０〜１５ｍｍの範囲としていること、の点で本発明の製法とは異なっている。
For comparison, the diamond-coated WC-based cemented carbide drills of the comparative examples shown in Table 3 (hereinafter simply referred to as “comparative example drills”) according to the steps (a) to (c) in the above manufacturing steps of the present invention drills 1 to 10. 1) to 10).
In addition, in the manufacturing method of comparative example drills 1 to 10, there is no mechanism for cooling the drill base, and therefore the distance between the drill and the filament is in the range of 10 to 15 mm in order to keep the substrate temperature properly, This is different from the production method of the present invention.
ついで、上記で製造した本発明ドリル１〜１０および比較例ドリル１〜１０について、ドリルの切れ刃部を切断して、チゼルエッジ部（ドリルの中央先端部から１００μｍの範囲内）と切刃外周部（ドリルの外周部の肩部から１００μｍの範囲内）をＳＥＭで観察し、それぞれの部分の３点について膜厚を測定し、測定値を平均することによって、切刃外周部の膜厚ｈ１およびチゼルエッジ部の膜厚ｈ２を求めた。
表２、３に、ｈ１，ｈ２，ｈ１／ｈ２の値を示す。
Next, for the inventive drills 1 to 10 and comparative drills 1 to 10 manufactured above, the cutting edge of the drill is cut, and the chisel edge (within a range of 100 μm from the center tip of the drill) and the outer periphery of the cutting edge (Within a range of 100 μm from the shoulder of the outer periphery of the drill) is observed with an SEM, the film thickness is measured at three points of each part, and the measured values are averaged to obtain the film thickness h1 of the outer periphery of the cutting edge The thickness h2 of the chisel edge portion was determined.
Tables 2 and 3 show the values of h1, h2, and h1 / h2.
また、本発明ドリル１〜１０および比較例ドリル１〜１０のチゼルエッジ部および切刃外周部について、Ａｒレーザーによるラマン分光測定を行い、ダイヤモンド由来の１３３３ｃｍ−１を中心とするピークの半価幅ｗ１、ｗ２をそれぞれ求めた。
表２、３に、ｗ１，ｗ２，ｗ１／ｗ２の値を示す。
Moreover, about the chisel edge part and cutting-blade outer peripheral part of this invention drill 1-10 and comparative example drill 1-10, the Raman spectroscopic measurement by Ar laser is performed, and the half-value width w1 of the peak centering on 1333 cm < -1 > derived from a diamond. , W2 was obtained.
Tables 2 and 3 show the values of w1, w2, and w1 / w2.
また、本発明ドリル１〜１０および比較例ドリル１〜１０のチゼルエッジ部および切刃外周部のダイヤモンド膜について、それぞれの圧縮残留応力の値を以下の測定法で測定（３点測定）し、その平均値から、切刃外周部の圧縮残留応力の値σ１、チゼルエッジ部の圧縮残留応力の値σ２を求めた。
即ち、Ｘ線回折装置にて、４０ｍＡ、２００ｋＶの電流と電圧にてＣｏ管球を用いて、Ｘ線を発生させ、ダイヤモンドの（３１１）のピークに関し、２θ−ｓｉｎ２ψ法により、ψ角を０から３９度まで変化させることで、測定を行った。
表２、３に、σ１，σ２，σ２／σ１の値を示す。
Moreover, about the diamond film of the chisel edge part of this invention drill 1-10 and comparative example drill 1-10, and a cutting-blade outer peripheral part, the value of each compressive residual stress is measured with the following measuring methods (three-point measurement), From the average value, the value σ1 of the compressive residual stress at the outer peripheral portion of the cutting edge and the value σ2 of the compressive residual stress at the chisel edge portion were obtained.
That is, an X-ray diffractometer is used to generate X-rays using a Co tube at a current and voltage of 40 mA, 200 kV, and the (311) peak of diamond is ψ angle by the 2θ-sin 2 ψ method. Was measured by changing the angle from 0 to 39 degrees.
Tables 2 and 3 show the values of σ1, σ2, and σ2 / σ1.
つぎに、上記本発明ドリル１〜１０および比較例ドリル１〜１０を用いて、以下の条件で、ＣＦＲＰとＡｌ合金Ａ７０７５の複合材（入口側がＣＦＲＰ材：１５ｍｍ、出口側がＡｌ材：５ｍｍ）のドリル穴開け試験を行った。
切削速度： １１０ ｍ／ｍｉｎ，
送り： ０．１２ ｍｍ／ｒｅｖ．，
穴深さ： ２０ ｍｍ（貫通穴），
上記の切削試験において、正常摩耗の場合は切れ刃の最大逃げ面摩耗幅が、０．３ｍｍを超えた時点で使用寿命とし、それまでの穴あけ加工数を測定した。
また、チッピング、ドリル折損等が原因で使用寿命に至った場合には、それまでの穴あけ加工数を測定した。
表４にこれらの測定結果を示す。
Next, using the above-described drills 1 to 10 and comparative drills 1 to 10, the composite material of CFRP and Al alloy A7075 (CFRP material on the inlet side: 15 mm, Al material on the outlet side: 5 mm) under the following conditions: A drilling test was conducted.
Cutting speed: 110 m / min,
Feed: 0.12 mm / rev. ,
Hole depth: 20 mm (through hole),
In the above cutting test, in the case of normal wear, the service life was determined when the maximum flank wear width of the cutting edge exceeded 0.3 mm, and the number of drilling operations was measured.
In addition, when the service life was reached due to chipping, drill breakage, etc., the number of drilling operations so far was measured.
Table 4 shows the measurement results.
表２〜表４の結果からも明らかなように、本発明ドリル１〜１０は、切刃外周部に比して、チゼルエッジ部のダイヤモンドの膜厚を相対的に薄くするとともに、ダイヤモンドの結晶性を低下せしめ、さらに、圧縮残留応力を適正な範囲に保つことによって、被削材との溶着発生が抑制されるとともに、チゼルエッジ部の鋭利さを保つことができるため、Ａｌ合金への食いつきを維持し、そのために異常なチッピングなどの損傷の発生が比較的少なく、さらに、長期の使用に亘って、すぐれた耐摩耗性を発揮しているため、概して工具寿命が長くなっていることがわかる。
つまり、ｈ1/ｈ2，ｗ１/ｗ２，σ2/σ1のいずれもが請求項１〜３記載の所定数値範囲内である本発明ドリル１，３，５，６，９については、摩耗形態は正常摩耗であって、しかも、穴あけ加工数も全て１５６穴以上であって、工具寿命が非常に長い。
また、ｗ１/ｗ２，σ2/σ1のいずれか一方あるいは両方が、請求項２，３記載の所定数値範囲外となったものは、チッピング発生によって工具寿命となるものの、穴あけ加工数は１００個前後であって、耐摩耗性に優れることがわかる。
これに対して、比較例ドリル１〜１０は、本発明ドリルに比して、穴あけ加工数が少ない（最大でも３１個）ばかりか、溶着などが原因で切削の早期に切れ刃にチッピング等の異常損傷を発生し、工具寿命も非常に短いことが明らかである。
As is clear from the results of Tables 2 to 4, the drills 1 to 10 of the present invention have a relatively thin film thickness of the diamond at the chisel edge portion as compared with the outer peripheral portion of the cutting edge, and the crystallinity of the diamond. In addition, by maintaining the compression residual stress within the proper range, the occurrence of welding with the work material can be suppressed and the sharpness of the chisel edge can be maintained, so the biting to the Al alloy is maintained. For this reason, the occurrence of damage such as abnormal chipping is relatively small, and further, since the excellent wear resistance is exhibited over a long period of use, the tool life is generally prolonged.
That is, for the drills 1, 3, 5, 6, and 9 of the present invention in which all of h1 / h2, w1 / w2, and σ2 / σ1 are within the predetermined numerical range according to claims 1 to 3, the wear form is normal wear. Moreover, the number of drilling operations is all 156 holes or more, and the tool life is very long.
In addition, if one or both of w1 / w2 and σ2 / σ1 are outside the predetermined numerical range according to claims 2 and 3, the tool life will be due to chipping, but the number of drilling operations will be around 100. Thus, it is understood that the wear resistance is excellent.
On the other hand, the comparative example drills 1 to 10 have not only a small number of drilling processes (31 at the maximum) as compared with the drill of the present invention, but also chipping at the cutting edge early due to welding or the like. It is clear that abnormal damage occurs and the tool life is very short.
本発明のダイヤモンド被覆超硬合金製ドリルは、ＣＦＲＰとＡｌの重ね合わせ穿孔などにおいて、耐チッピング性に優れるばかりか、長期の使用に亘ってすぐれた耐摩耗性を発揮することから、切削加工の省エネ化、低コスト化に十分満足に対応できるものである。
The diamond-coated cemented carbide drill of the present invention not only excels in chipping resistance in the overlap drilling of CFRP and Al, but also exhibits excellent wear resistance over a long period of use. It can cope with energy saving and cost reduction sufficiently satisfactorily.
Claims (3)
上記ドリルの切刃外周部の膜厚をｈ１とし、チゼルエッジ部の膜厚をｈ２とした時に、ｈ１／ｈ２の値が１．２以上２．０以下であることを特徴とするダイヤモンド被覆超硬合金製ドリル。 A tungsten carbide-based cemented carbide containing tungsten carbide and cobalt as main components and containing 3 to 15% by mass of cobalt is used as a drill base, and diamond having an average film thickness of 5 to 30 μm on the outer periphery of the tip of the drill base In a diamond-coated cemented carbide drill with a film coating,
Diamond coated carbide characterized in that the value of h1 / h2 is 1.2 or more and 2.0 or less when the film thickness of the outer peripheral part of the cutting edge of the drill is h1 and the film thickness of the chisel edge part is h2. Alloy drill.
When the compressive residual stress values at the outer peripheral portion and the chisel edge portion of the drill are σ1 and σ2, respectively, the value of σ2 is 1.8 GPa or less and the value of σ2 / σ1 is 0.6 or more and 0.00. The diamond-coated cemented carbide drill according to claim 1 or 2, wherein the drill is made of 9 or less.
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| JPWO2019039001A1 (en) * | 2017-08-22 | 2020-07-30 | 住友電工ハードメタル株式会社 | Rotary cutting tool and manufacturing method thereof |
| JP7036437B2 (en) | 2017-08-22 | 2022-03-15 | 住友電工ハードメタル株式会社 | Rotary cutting tools and their manufacturing methods |
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