JP2005319558A - Cutting edge replaceable-type finishing radius end mill - Google Patents
Cutting edge replaceable-type finishing radius end mill Download PDFInfo
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本発明は、刃先交換式仕上げ用ラジアスエンドミルにおける切屑形成の形態と排出改善に関するものであり、特に工具ホルダーの剛性を維持したまま、切削加工における切屑の工具及び被削材への溶着を防止する切屑収納溝を備えるとともに、切屑排出に適した一定形状の切屑を形成するのに適した切刃を備えた刃先交換式仕上げ用ラジアスエンドミルに関するものである。 TECHNICAL FIELD The present invention relates to chip formation and discharge improvement in a radius end mill for replaceable cutting edges, and in particular, prevents welding of chips to a tool and a work material in cutting while maintaining the rigidity of a tool holder. The present invention relates to a radius end mill for exchangeable cutting edge including a chip storage groove and a cutting blade suitable for forming a chip having a fixed shape suitable for chip discharge.
プレス型やプラ型等の金型仕上げ加工では、ボールエンドミル等の切削工具を用いて倣い加工を行う。この倣い加工の時は、被削材の表面は平坦な領域と凹凸を有する領域とが共存している。最終的な仕上げ面粗さの狙い値が５μｍ程度になるように加工条件を設定するが、実際の加工後はこの狙い値とは異なり、約２０〜３０μｍ前後の面粗さを示すため、金型の品質としての面粗さを満足することが出来ず、後工程で手作業による磨き加工が行われる。これは、工具形状及びピックフィードにより定義される面粗さの理論値が、工具形状及び加工条件より算出されるものであることから、この理論値と測定値とに大きな差が生じるためである。この面粗さの差が生じる原因は、切削工具と被削材との間において擦れや溶着などが発生し、被削材面粗さに悪影響を与え、時には切削工具の切刃部に生じるチッピングや欠損が原因となる場合もある。そこで、特許文献１、２に切刃部の形状に工夫を加え、被削材面粗さの改善又は切刃部のチッピングや欠損を回避するための技術が開示されている。
特許文献１は、仕上げ加工用に用いるスローアウエイ式エンドミルにおいて、切刃部の形状が、外周刃と略垂直に位置する底刃と、底刃コーナーに外周刃と底刃に接する略１／４円弧からなるコーナーアール刃とを備えた切刃チップを記載している。更に、底刃は僅かな中低勾配をもつことが開示されている。しかし、底刃は僅かな中低勾配しか持たないため、被削材と工具間では切屑の噛み込みや、擦れや溶着が発生し、平面加工における仕上げ加工では一般的なボールエンドミルと同等程度の表面粗さとなってしまう。
特許文献２は、ラジアスエンドミルの回転軸中心近傍に中低勾配を有する内周刃を設けた技術が開示されている。この技術により、工具先端に周速が零となる点を作らないことから耐欠損性を向上させ、工具の長寿命化を提案している。しかしながら、上記形状では、工具の最下点、即ち周速が零ではないが非常に遅い速度で被削材と工具が接触する点があり、擦れや溶着を完全には抑制することが出来ずい。特許文献２には、被削材の面粗さの改善案については何ら考察がなされていない。
特許文献３、４には、インサートの固定方法に関する技術が開示されている。特許文献３は、インサートを工具本体に強固に固定する技術がボールエンドミル、ラジアスエンドミルなどについて開示されている。特許文献４でも、インサートの取り付け精度向上に関する技術が開示されている。
In mold finishing such as a press die and a plastic die, copying is performed using a cutting tool such as a ball end mill. At the time of this copying, the surface of the work material has both a flat region and a region having unevenness. The processing conditions are set so that the final finished surface roughness target value is about 5 μm. However, after actual processing, the surface roughness is about 20-30 μm, which is different from this target value. The surface roughness as mold quality cannot be satisfied, and manual polishing is performed in the subsequent process. This is because the theoretical value of the surface roughness defined by the tool shape and pick feed is calculated from the tool shape and machining conditions, so that there is a large difference between this theoretical value and the measured value. . The cause of this difference in surface roughness is that the cutting tool and the work material are rubbed and welded, which adversely affects the surface roughness of the work material and sometimes chipping that occurs at the cutting edge of the cutting tool. It can also be caused by defects. Therefore, Patent Documents 1 and 2 disclose a technique for improving the surface roughness of the work material or avoiding chipping or chipping of the cutting edge part by devising the shape of the cutting edge part.
Patent Document 1 discloses a throwaway type end mill used for finishing, in which the shape of the cutting edge portion is a bottom blade that is positioned substantially perpendicular to the outer peripheral edge, and approximately 1/4 that the bottom edge is in contact with the outer peripheral edge and the bottom edge. A cutting edge tip having a corner radius blade made of an arc is described. Furthermore, it is disclosed that the bottom blade has a slight medium to low slope. However, since the bottom blade has only a slight medium to low gradient, chip biting, rubbing and welding occur between the work material and the tool. It becomes surface roughness.
Patent Document 2 discloses a technique in which an inner peripheral blade having a medium to low gradient is provided in the vicinity of the rotational axis center of a radius end mill. By this technique, since the point where the peripheral speed becomes zero is not made at the tip of the tool, it is proposed that the fracture resistance is improved and the tool life is extended. However, with the above shape, there is a point at which the work material and the tool come into contact at the lowest point of the tool, that is, the peripheral speed is not zero, but at a very slow speed, and it is not possible to completely suppress rubbing and welding. . In Patent Document 2, no consideration is given to a plan for improving the surface roughness of the work material.
本発明は、刃先交換式の仕上げ用ラジアスエンドミルにおいて、被削材の表面が平坦な領域や凹凸を有する領域などが共存している倣い加工時においても、被削材の面粗さを改善することである。このため。切削工具と被削材との間において生じる擦れや溶着などの発生を防止し、切削工具の切刃部の強度を改善して耐チッピングや耐欠損を改善した刃先交換式の仕上げ用ラジアスエンドミルを提供することにある。 The present invention improves the surface roughness of a work material in a radius end mill for exchanging cutting edges, even during profiling in which a work material has a flat surface or an uneven surface. That is. For this reason. A radius end mill with a replaceable edge that prevents chipping and chipping by preventing the occurrence of rubbing and welding between the cutting tool and the work material and improving the strength of the cutting edge of the cutting tool. It is to provide.
本発明のラジアスエンドミルは、軸線回りに回転される工具本体の先端部に、該軸線を含む平面方向に延びるスリット状のインサート取付座が形成され、このインサート取付座に、外周側に略円弧状に延びる切刃を備えたインサートが、該切刃を工具先端側に突出させて着脱可能に取り付けられてなる刃先交換式仕上げ用ラジアスエンドミルにおいて、該インサートの切刃の形状は、外周側の該円弧状切刃の半径をｒ１とし、工具直径をＤとした時、０．３１Ｄ≦ｒ１≦０．４５Ｄ、Ｄ≧８ｍｍで形成され、該円弧状切刃の最下点において同一接線を有し、回転軸中心に向かう内周刃の半径がｒ２を有する他の円弧状切刃が形成され、ｒ１＞ｒ２の関係を有して形成されていることを特徴とする刃先交換式仕上げ用ラジアスエンドミルである。本構成を採用することによって、被削材の表面が平坦な領域や凹凸を有する領域などが共存している倣い加工時においても、被削材の面粗さを改善することができる。更に切削工具と被削材との間において生じる擦れや溶着などの発生を防止し、切削工具の切刃部の強度を改善して耐チッピングや耐欠損を改善し、被削材面粗さを改善することができる。 In the radius end mill of the present invention, a slit-like insert mounting seat extending in the plane direction including the axis is formed at the tip of the tool body rotated around the axis, and the insert mounting seat has a substantially arc shape on the outer peripheral side. In a radius end mill for exchangeable cutting edge, in which an insert having a cutting blade extending in the direction is detachably attached by projecting the cutting blade toward the tool tip side, the shape of the cutting edge of the insert is When the radius of the arcuate cutting edge is r1 and the tool diameter is D, it is formed with 0.31D ≦ r1 ≦ 0.45D, D ≧ 8 mm, and has the same tangent at the lowest point of the arcuate cutting edge Radial end mill for exchangeable cutting edge, characterized in that another arcuate cutting edge having a radius of r2 of the inner peripheral edge toward the rotation axis center is formed and has a relation of r1> r2. IsBy adopting this configuration, it is possible to improve the surface roughness of the work material even at the time of profiling in which an area where the surface of the work material is flat or an area having unevenness coexists. Furthermore, it prevents the occurrence of rubbing and welding between the cutting tool and the work material, improves the strength of the cutting edge of the cutting tool, improves chipping resistance and chipping resistance, and improves the surface roughness of the work material. Can be improved.
本発明の刃先交換式の仕上げ用ラジアスエンドミルは、インサートの他の円弧状切刃の半径ｒ２が、０．１≦ｒ２≦５（ｍｍ）の関係を有して形成されていることが好ましい。 In the radius end mill for finishing according to the present invention, the radius r2 of the other arcuate cutting edge of the insert is preferably formed so as to have a relationship of 0.1 ≦ r2 ≦ 5 (mm).
本発明は、被削材の表面が平坦な領域や凹凸を有する領域などが共存している倣い加工時においても、被削材の面粗さを改善する。切削工具と被削材との間において生じる擦れや溶着などの発生を防止し、切削工具の切刃部の強度を改善して耐チッピングや耐欠損を改善した刃先交換式の仕上げ用ラジアスエンドミルを提供することができる。本発明の適用によって被削材面粗さを改善することができる。 The present invention improves the surface roughness of a work material even at the time of profiling in which an area where the surface of the work material is flat or an area having unevenness coexists. A radius end mill with a replaceable cutting edge that prevents the occurrence of rubbing and welding between the cutting tool and the work material and improves the strength of the cutting edge of the cutting tool to improve chipping resistance and chipping resistance. Can be provided. By applying the present invention, the surface roughness of the work material can be improved.
図１から図４に本発明の刃先交換式仕上げ用ラジアスエンドミルの実施例を図示する。図１は刃先交換式仕上げ用ラジアスエンドミルの正面図であり、図２は本発明の刃先交換式仕上げ用ラジアスエンドミルのインサートの正面図、図３はインサートの側面図である。図４に示す様に、本発明の刃先交換式仕上げ用ラジアスエンドミルに装着するインサートの切刃の形状は、外周側の該円弧状切刃の半径をｒ１、円弧中心をｆとし、工具直径をＤとした時、０．３１Ｄ≦ｒ１≦０．４５Ｄで形成されている。これは、ｒ１が０．３１Ｄ未満の場合はｒ１が小さすぎて、傾斜面の加工において良好な面粗さが得られないためである。またｒ１が０．４５Ｄを超えて大きい場合は半径が大きすぎて、円弧状切刃の最下点において十分な周速度を得られないため、被削材表面の面粗さが悪化するためである。好ましくはｒ１は０．３３Ｄ程度に設定すると良好な被削材表面の面粗さが得られる。ここで、本発明の工具直径Ｄはφ８ｍｍ以上を対象とする。また、該円弧状切刃の最下点において同一接線を有し、回転軸中心に向かう内周刃の半径がｒ２、円弧中心をｇとする他の円弧状切刃が形成され、ｒ１＞ｒ２の関係を有して形成されることが必要である。工具回転軸中心の形状が中低部を有する形状となることで、工具最下点の周速が０となる点を排除し、ｒ１とｒ２とを規定して、更にｒ１＞ｒ２の関係を有する切刃を形成することにより、高品質な被削材の表面粗さを得ることが可能である。特に、ｒ２を有する内周刃を備えている事は、被削材の表面に凹凸を有する倣い加工時において、被削材の面粗さを改善することに有効である。これは、工具最下点における切刃のすかし形状が、被削材の表面粗さに悪影響を及ぼさない程度に形成でき、切刃の耐チッピングや耐欠損性に好適に作用するからである。ここで、円弧中心ｆとｇは、工具最下点ｃの接線に垂直な直線上にある。
図３に示す様に、本発明の仕上げ用ラジアスエンドミルの切刃形状は直刃形状とし、すくい面を平らな面とすることが好ましい。この理由は、仕上げ用工具においては、刃先強化を行うよりも切れ味を向上させ、切削抵抗を低減させる必要性があることによる。また、すくい角を０度とすることが好ましい。これによって、切削抵抗を更に低減させることができる。
1 to 4 show an embodiment of a radius end mill for exchanging blade edge according to the present invention. FIG. 1 is a front view of a radius end mill for blade edge replacement type finishing, FIG. 2 is a front view of an insert of the radius end mill for blade edge replacement type finishing of the present invention, and FIG. 3 is a side view of the insert. As shown in FIG. 4, the shape of the cutting edge of the insert attached to the radius end mill for exchangeable cutting edge according to the present invention is such that the radius of the arcuate cutting edge on the outer peripheral side is r1, the center of the arc is f, and the tool diameter is When D, 0.31D ≦ r1 ≦ 0.45D. This is because when r1 is less than 0.31D, r1 is too small to obtain good surface roughness in the processing of the inclined surface. In addition, when r1 is larger than 0.45D, the radius is too large and a sufficient peripheral speed cannot be obtained at the lowest point of the arcuate cutting edge, so that the surface roughness of the work material surface is deteriorated. is there. Preferably, when r1 is set to about 0.33D, good surface roughness of the work material can be obtained. Here, the tool diameter D of the present invention is targeted for φ8 mm or more. Further, another arc-shaped cutting edge having the same tangent at the lowest point of the arc-shaped cutting edge, the radius of the inner peripheral edge toward the rotation axis center being r2, and the arc center being g is formed, and r1> r2 It is necessary to form the following relationship. Since the shape of the center of the tool rotation axis has a middle and low part, the point at which the peripheral speed at the lowest point of the tool becomes 0 is eliminated, r1 and r2 are defined, and the relationship of r1> r2 is further established. By forming the cutting edge having, it is possible to obtain a high-quality surface roughness of the work material. In particular, the provision of the inner peripheral edge having r2 is effective in improving the surface roughness of the work material during the copying process in which the surface of the work material has irregularities. This is because the watermark shape of the cutting edge at the lowest point of the tool can be formed to such an extent that it does not adversely affect the surface roughness of the work material, and acts favorably on chipping resistance and chipping resistance of the cutting edge. . Here, the arc centers f and g are on a straight line perpendicular to the tangent to the tool lowest point c.
As shown in FIG. 3, it is preferable that the cutting edge shape of the finishing radius end mill of the present invention is a straight blade shape and the rake face is a flat surface. The reason for this is that in the finishing tool, it is necessary to improve the sharpness and to reduce the cutting resistance rather than to enhance the cutting edge. The rake angle is preferably 0 degree. Thereby, cutting resistance can be further reduced.
図４、５に示す様に、工具内周刃のｒ２は、０．１≦ｒ２≦５（ｍｍ）の関係を有して形成されていることが好ましい。上記の範囲内に規定することで、被削材の仕上面の品質を向上させることが可能である。これは、内周刃を上記の範囲内に規定することで、切刃と被削材との接触長さを低減させ、ビビリ振動やチッピングの発生を抑制するとともに、切屑の噛み込みによるキズの発生を低減する効果がある。より好ましくは２≦ｒ２≦３（ｍｍ）に設定すると良い。切刃の最下点から回転軸中心に向かって内周側に向かう円弧状の内周刃の１部が直線状をなし、該直線が円弧状内周刃における点ｄの接線となっている場合、該直線が切刃の最下点における接線となす角度をθ１（以下、スカシ角度と称する。）。ここで、θ１は、５≦θ１≦３０度に設定することが好ましい。これによって、被削材の表面が凹凸を有する倣い加工時の傾斜切込みにも適切に対応することが可能となる。θ１を５度未満にすると、内周刃と被削材表面との距離が接近し、内周刃の切屑噛み込みにより、被削材表面にキズが発生する不都合が生じるためである。また、θ１が３０度を超えて大きい場合には、内周刃が工具軸方向に伸び、工具の作成が困難になる。また、傾斜切込みにおいて内周刃と被削材との距離が広くなり、ビビリ振動やチッピングの発生する不都合が生じるためである。より好ましくは８≦θ１≦１５度に設定することが好ましい。また、θ１は幾何学的に、半径がｒ２を有する円弧中心ｇに形成される中心角と同値である。 As shown in FIGS. 4 and 5, it is preferable that r2 of the tool inner peripheral edge is formed to have a relationship of 0.1 ≦ r2 ≦ 5 (mm). By defining within the above range, it is possible to improve the quality of the finished surface of the work material. This is because, by defining the inner peripheral edge within the above range, the contact length between the cutting edge and the work material is reduced, chatter vibration and chipping are suppressed, and scratches caused by chip biting are reduced. This has the effect of reducing the occurrence. More preferably, 2 ≦ r2 ≦ 3 (mm) is set. A part of the arc-shaped inner peripheral blade from the lowest point of the cutting edge toward the inner peripheral side toward the center of the rotation axis forms a straight line, and the straight line is a tangent to the point d on the arc-shaped inner peripheral blade. In this case, the angle formed by the straight line and the tangent at the lowest point of the cutting edge is θ1 (hereinafter referred to as a skew angle). Here, θ1 is preferably set to 5 ≦ θ1 ≦ 30 degrees. As a result, it is possible to appropriately cope with an inclined cut at the time of copying in which the surface of the work material has irregularities. This is because if θ1 is less than 5 degrees, the distance between the inner peripheral blade and the surface of the work material approaches, and there is a disadvantage that scratches occur on the surface of the work material due to the biting of chips of the inner peripheral blade. When θ1 is larger than 30 degrees, the inner peripheral blade extends in the tool axis direction, making it difficult to create a tool. In addition, the distance between the inner peripheral blade and the work material is increased in the inclined cutting, and inconveniences such as chatter vibration and chipping occur. More preferably, it is set to 8 ≦ θ1 ≦ 15 degrees. Further, θ1 is geometrically equivalent to the central angle formed at the arc center g having a radius r2.
図６、７に示す様に、本発明の刃先交換式仕上げ用ラジアスエンドミルに装着するインサートの切刃の形状は、外周刃である該円弧状切刃から工具最下点ｃを通って内周刃である該他の円弧状切刃に向かうに従って、法線方向の逃げ角が大きくなることが好ましい。これは、工具外周刃から最下点ｃを通って内周刃に至る各点において、工具回転数が一定の場合、切削速度が異なるためである。切削速度が異なる場合、逃げ角が一定だと工具の摩耗量が切刃各点において異なる。一方で、工具寿命は摩耗量が最も大きくなる時点で判定されるため、夫々切削速度が異なる点において適切な法線方向の逃げ角を設定することで、工具寿命の長寿命化及び高品質な面粗さを得ることが出来る。ここで言う法線方向の逃げ角とは、例えば図６におけるＢ−Ｂ断面を示した図７の様に、切刃の法線と切刃とのなす角度θ３によって示される。θ３は、外周刃である該円弧状切刃から最下点ｃを通って内周刃である該他の円弧状切刃に向かうに従って大きくなることが好ましいが、更にθ３は夫々の切刃領域毎に好適な値を有することが好ましい。そこで図６で示される切刃を５つの領域に分割した。第１の直線Ｌ１の領域は、切刃の最外周点ａからバックテーパ角度βを有して回転軸方向に延びる外周刃領域を示し、この領域のθ３をＬ１（θ３）で表す。同じく第２の曲線Ｒ１ａの領域は、切刃の最外周点ａから最下点ｃに向かう円弧部領域を示し、この領域のθ３をＲ１ａ（θ３）で表す。第３の曲線Ｒ１ｂ領域は、最下点ｃから最外周点ａに向かう円弧部領域を示し、この領域のθ３をＲ１ｂ（θ３）で表す。第４の曲線Ｒ２領域は、切刃の最下点ｃから円弧中心ｇに形成される中心角θ１で形成される円弧部領域を示し、この領域のθ３をＲ２（θ３）で表す。第５の直線Ｌ２領域は、直線状をなす内周刃領域を示し、この領域のθ３をＬ２（θ３）で表す。この時、Ｌ１（θ３）≦Ｒ１ａ（θ３）＜Ｒ１ｂ（θ３）≦Ｒ２（θ３）≦Ｌ２（θ３）の関係を有して形成されていると良い。好ましくは、Ｌ１（θ３）が、３≦Ｌ１（θ３）≦１３度、Ｒ１ａ（θ３）が、３≦Ｒ１ａ（θ３）≦１３度、Ｒ１ｂ（θ３）が、５≦Ｒ１ｂ（θ３）≦１５度、Ｒ２（θ３）が、５≦Ｒ２（θ３）≦１５度、Ｌ２（θ３）が、７≦Ｌ２（θ３）≦１７度である。更に、より好ましくは、Ｌ１（θ３）が、５≦Ｌ１（θ３）≦９度、Ｒ１ａ（θ３）が、５≦Ｒ１ａ（θ３）≦９度、Ｒ１ｂ（θ３）が、７≦Ｒ１ｂ（θ３）≦１１度、Ｒ２（θ３）が、７≦Ｒ２（θ３）≦１１度、Ｌ２（θ３）が、９≦Ｌ２（θ３）≦１３度にすると良い。
上記の様に数値規定を行う理由は、以下の通りである。即ち、Ｌ１領域やＲ１ａ領域のθ３は切削速度が高いため、θ３が小さいと摩耗進行が早く進み、逆にθ３が大きすぎるとチッピング等が発生するためである。また、Ｒ１ｂ領域やＲ２領域においては切削速度が低いため、逃げ角を小さくすることで工具と被削材の接触面を減少させ、切削抵抗を低下させることが出来る。この領域では外周刃領域よりも小さなθ３を有することが望ましい。また、切屑の噛み込み防止のため、直線Ｌ２領域のθ３は、Ｒ１ｂ領域やＲ２領域のθ３よりも小さなθ３を有することが望ましい。上記の場合において、曲線Ｒ１ａと曲線Ｒ１ｂの円弧長さの和は、点ｆを中心とした半径ｒ１の円周の１／４に相当し、曲線Ｒ１ａ領域から曲線Ｒ１ｂ領域に移行する途中には、点ａから点ｃへ向かう間に位置する境界点ｂによって両者が区別される。また、曲線Ｒ１ｂの円弧を形成する中心角をθ２とすると、曲線Ｒ１ａの円弧を形成する中心角は、９０−θ２で表される。更にθ２の角度範囲は、１０≦θ２≦４５度に規定することが好ましい。θ２を上記の範囲に規定する理由は、θ２が１０度未満の場合には、境界点ｂでの周速が遅いため、好適なθ３を得ることが出来ない。また、θ２が４５度を超えて大きい場合には、点ｂにおける切刃の周速が速くなり、ここでも好適なθ３を得ることが出来ないためである。
As shown in FIGS. 6 and 7, the shape of the cutting edge of the insert attached to the radius end mill for replaceable cutting edge according to the present invention is such that the circular cutting edge which is the outer peripheral blade passes through the tool lowest point c to the inner periphery. The clearance angle in the normal direction is preferably increased toward the other arcuate cutting edge which is a blade. This is because, at each point from the tool outer peripheral blade to the inner peripheral blade through the lowest point c, the cutting speed is different when the tool rotation number is constant. When the cutting speed is different, the wear amount of the tool is different at each point of the cutting edge when the clearance angle is constant. On the other hand, since the tool life is determined when the amount of wear becomes the largest, by setting an appropriate normal direction clearance angle at different cutting speeds, the tool life can be extended and high quality can be achieved. Surface roughness can be obtained. Here, the clearance angle in the normal direction is indicated by an angle θ3 formed by the normal line of the cutting edge and the cutting edge as shown in FIG. 7 showing the BB cross section in FIG. θ3 is preferably increased from the arcuate cutting edge as the outer peripheral edge toward the other arcuate cutting edge as the inner peripheral edge through the lowest point c, and further, θ3 is each cutting edge region. It is preferable to have a suitable value for each. Therefore, the cutting blade shown in FIG. 6 was divided into five regions. The region of the first straight line L1 indicates an outer peripheral blade region extending in the rotation axis direction with a back taper angle β from the outermost peripheral point a of the cutting blade, and θ3 of this region is represented by L1 (θ3). Similarly, the region of the second curve R1a indicates an arc portion region from the outermost peripheral point a to the lowest point c of the cutting edge, and θ3 of this region is represented by R1a (θ3). The third curve R1b region indicates an arc portion region from the lowest point c to the outermost peripheral point a, and θ3 of this region is represented by R1b (θ3). The fourth curve R2 region indicates an arc portion region formed by a central angle θ1 formed from the lowest point c of the cutting edge to the arc center g, and θ3 of this region is represented by R2 (θ3). The fifth straight line L2 region indicates a linear inner peripheral blade region, and θ3 of this region is represented by L2 (θ3). At this time, it may be formed so as to have a relationship of L1 (θ3) ≦ R1a (θ3) <R1b (θ3) ≦ R2 (θ3) ≦ L2 (θ3). Preferably, L1 (θ3) is 3 ≦ L1 (θ3) ≦ 13 degrees, R1a (θ3) is 3 ≦ R1a (θ3) ≦ 13 degrees, and R1b (θ3) is 5 ≦ R1b (θ3) ≦ 15 degrees. , R2 (θ3) is 5 ≦ R2 (θ3) ≦ 15 degrees, and L2 (θ3) is 7 ≦ L2 (θ3) ≦ 17 degrees. More preferably, L1 (θ3) is 5 ≦ L1 (θ3) ≦ 9 degrees, R1a (θ3) is 5 ≦ R1a (θ3) ≦ 9 degrees, and R1b (θ3) is 7 ≦ R1b (θ3). ≦ 11 degrees, R2 (θ3) is preferably 7 ≦ R2 (θ3) ≦ 11 degrees, and L2 (θ3) is preferably 9 ≦ L2 (θ3) ≦ 13 degrees.
The reason why the numerical values are specified as described above is as follows. That is, θ3 in the L1 region and the R1a region has a high cutting speed, so if θ3 is small, wear progresses quickly, and conversely if θ3 is too large, chipping or the like occurs. Further, since the cutting speed is low in the R1b region and the R2 region, the contact surface between the tool and the work material can be reduced by reducing the clearance angle, and the cutting resistance can be reduced. In this region, it is desirable to have θ3 smaller than that of the outer peripheral blade region. In order to prevent chips from getting caught, it is desirable that θ3 in the straight line L2 region has θ3 smaller than θ3 in the R1b region and the R2 region. In the above case, the sum of the arc lengths of the curve R1a and the curve R1b corresponds to ¼ of the circumference of the radius r1 with the point f as the center, and during the transition from the curve R1a region to the curve R1b region. The boundary point b located between the point a and the point c is distinguished from each other. If the central angle forming the arc of the curve R1b is θ2, the central angle forming the arc of the curve R1a is represented by 90−θ2. Furthermore, the angle range of θ2 is preferably defined as 10 ≦ θ2 ≦ 45 degrees. The reason for defining θ2 within the above range is that when θ2 is less than 10 degrees, the peripheral speed at the boundary point b is slow, and thus a suitable θ3 cannot be obtained. Further, when θ2 is larger than 45 degrees, the peripheral speed of the cutting edge at point b is increased, and a suitable θ3 cannot be obtained here.
本発明のラジアスエンドミルは、２番逃げの角度を有することも可能である。図７に示す様に、２番逃げの角度をθ４とすると、θ４は１５≦θ４≦３０度の範囲にすることが好ましい。この理由は、工具ヒール部と被削材とが接触する可能性を回避するためである。切刃稜線部から２番逃げの開始点までの距離Ｈは、工具直径に依存して変化させる必要がある。Ｈ値、１／１００Ｄ≦Ｈ≦１／１０Ｄの範囲とすると良い。 The radius end mill of the present invention can also have a second relief angle. As shown in FIG. 7, when the angle of the second relief is θ4, θ4 is preferably in the range of 15 ≦ θ4 ≦ 30 degrees. The reason for this is to avoid the possibility of contact between the tool heel portion and the work material. The distance H from the cutting edge ridge line portion to the starting point of the second relief needs to be changed depending on the tool diameter. It is good to set it as the range of H value and 1 / 100D <= H <= 1 / 10D.
本発明例１から１２の仕上げ用ラジアスエンドミルのインサートを超硬合金にて作製し、金型加工を想定し、被削材表面に傾斜部と平坦部とを併せ持つ倣い加工における切削試験を行った。また、比較例１４、１５のインサートも作製した。夫々の切刃形状の仕様を表１に示した。また、従来例１６のラジアスエンドミルは、工具径がφ３０ｍｍ、コーナーＲ切刃の円弧半径が３ｍｍのものを使用し、従来例１７のボールエンドミルは、工具径がφ３０ｍｍ、切刃の円弧半径が１５ｍｍのものを使用した。評価対象は、被削材の平坦加工部及び傾斜角５度の加工面部とし、各工具での仕上面の最大表面粗さＲｍａｘ値を評価した。表１に各工具での最大表面粗さも併記した。なお、切削条件の半径方向切込み量は、試験対象とする工具の直径に対して適切な値を規定し、試験を行った。 The finishing radius end mill inserts of Examples 1 to 12 of the present invention were made of cemented carbide, and a cutting test was performed in a copying process in which both the inclined portion and the flat portion were formed on the surface of the work material, assuming die processing. . In addition, inserts of Comparative Examples 14 and 15 were also produced. The specifications of each cutting edge shape are shown in Table 1. The radius end mill of Conventional Example 16 uses a tool diameter of 30 mm and the corner radius of the cutting edge of the corner R is 3 mm. The Ball End Mill of Conventional Example 17 uses a tool diameter of 30 mm and the radius of the cutting edge of 15 mm. I used one. Evaluation targets were a flat processed portion of the work material and a processed surface portion having an inclination angle of 5 degrees, and the maximum surface roughness Rmax value of the finished surface of each tool was evaluated. Table 1 also shows the maximum surface roughness of each tool. In addition, the cutting amount in the radial direction was determined by specifying an appropriate value for the diameter of the tool to be tested.
（切削条件）
加工方法：倣い加工による仕上げ加工
被削材 ：Ｓ５０Ｃ、硬さはＨＢ２２０
軸方向切込み量：０．３ｍｍ
半径方向切込み量：工具直径Ｄが３０ｍｍの時、０．８ｍｍ
工具直径Ｄが２０ｍｍの時、０．６ｍｍ
工具直径Ｄが１０ｍｍの時、０．４ｍｍ
工具直径Ｄが８ｍｍの時、０．３ｍｍ
切削速度：２００ｍ／ｍｉｎ
１刃当りの送り量：０．３７５ｍｍ／刃
切削油：無し、乾式切削
表１より、本発明例１から４は工具直径をφ３０、φ２０、φ１０、φ８と変化させ、それに伴ってｒ１値を設定し、その他の工具形状パラメータは同一の値とした工具を製作した。切削試験結果より、本発明が規定したパラメータの範囲内において、工具直径を変化させた場合でも、仕上面最大粗さが１０μｍ以下を示し、良好な被削材の表面状態を得られた。この被削材表面の状態は平坦部、傾斜部共に良好な面粗さであった。これに対して、比較例１４及び１５は、本発明例１のｒ１値以外の工具形状パラメータは同一の値とした工具である。表１の結果より、比較例１４及び１５は、内周刃を備えることによって５度傾斜部の加工に対応はできたものの、比較例１４のｒ１が８．５ｍｍの設定と小さすぎるため、傾斜部において十分なＲｍａｘを得ることが出来なかった。また、比較例１４はｒ１が１４ｍｍの設定と大きすぎたため、工具最下点において周速を十分に得ることが出来ず、被削材の表面にキズが発生し、Ｒｍａｘが悪化した。
本発明例１３は、ｒ１を１３．５ｍｍに設定したことにより、被削材表面の面粗さの劣化を満足できるレベルに抑えることができた。また、従来例１６では、傾斜部において満足の行く面粗さを得られなかった。これは、工具最下点から回転軸中心に向かう内周刃において、面粗さの改善に対する配慮がなされていないためであると考えられる。従来例１７でも、平坦部、傾斜部共に満足の行く面粗さを得られなかった。本発明例５、６は、本発明例１に対してθ１を変えた工具である。本発明例５ではθ１が５度、本発明例６ではθ１が３０度として工具の製作を行った。表１より、本発明例５、６は本発明例１よりも若干大きなＲｍａｘを示したが、十分な被削材表面粗さを得ることが出来た。但し、θ１をより大きな値に設定した場合には、より大きなＲｍａｘを示すことが予想される。これは、θ１が３０度を超えて大きい場合では、びびり振動やチッピングが発生するためである。一方、θ１が５度未満の場合では、工具の内周切刃と被削材表面との間隔が狭くなり、切屑の噛み込みが発生する不都合が考えられる。
本発明例７はθ２を１０度、本発明例８はθ２を４５度として工具の製作を行い、本発明例１に対してθ２のみを変化させた。表１の試験結果より、θ２が１０≦θ２≦４５度の範囲内であれば、良好な仕上面粗さが得られることを確認した。本発明例９から１２は、本発明例１のｒ２値以外の工具形状パラメータは同一の値とした工具である。本発明例９はｒ２を０．０２ｍｍ、本発明例１０はｒ２を０．２ｍｍ、本発明例１１はｒ２を４ｍｍ、本発明例１２はｒ２を６ｍｍとした。表１より、本発明例９では、工具最下点の工具切刃稜線がｒ１からｒ２に変化する点において、ｒ２が小さすぎるために平坦部の加工において被削材表面にキズが発生した。また、本発明例１０では、本発明例９のｒ２よりも大きな値であったため、被削材表面にキズは発生せず、良好な面粗さを示した。本発明例１１では、本発明例１０と同様に、良好な被削材面粗さを示したが、本発明例１２では、切屑の噛み込みによるキズが発生し、被削材の面粗さに悪影響を与えた。
(Cutting conditions)
Machining method: Finishing by profiling Work material: S50C, hardness is HB220
Axial depth of cut: 0.3 mm
Radial depth of cut: 0.8mm when tool diameter D is 30mm
0.6mm when tool diameter D is 20mm
0.4mm when tool diameter D is 10mm
0.3mm when tool diameter D is 8mm
Cutting speed: 200 m / min
Feed per tooth: 0.375 mm / blade Cutting oil: None, dry cutting From Table 1, Examples 1 to 4 of the present invention change the tool diameter to φ30, φ20, φ10, and φ8, and accordingly change the r1 value. The tool was set with the same values for the other tool shape parameters. From the cutting test results, even when the tool diameter was changed within the parameter range defined by the present invention, the finished surface maximum roughness was 10 μm or less, and a good surface condition of the work material was obtained. The surface condition of the work material was good surface roughness for both the flat part and the inclined part. On the other hand, Comparative Examples 14 and 15 are tools in which the tool shape parameters other than the r1 value of Example 1 of the present invention have the same value. From the results of Table 1, although Comparative Examples 14 and 15 were able to cope with the machining of the 5-degree inclined portion by providing the inner peripheral blade, the r1 of Comparative Example 14 was too small with the setting of 8.5 mm, A sufficient Rmax could not be obtained in the part. In Comparative Example 14, r1 was too large at a setting of 14 mm, so that a sufficient peripheral speed could not be obtained at the lowest point of the tool, scratches were generated on the surface of the work material, and Rmax was deteriorated.
In Invention Example 13, by setting r1 to 13.5 mm, the deterioration of the surface roughness of the work material surface could be suppressed to a satisfactory level. In Conventional Example 16, satisfactory surface roughness could not be obtained at the inclined portion. This is considered to be because no consideration is given to the improvement of the surface roughness at the inner peripheral blade from the tool lowest point toward the center of the rotation axis. Even in Conventional Example 17, satisfactory surface roughness could not be obtained for both the flat portion and the inclined portion. Invention Examples 5 and 6 are tools in which θ1 is changed from that of Invention Example 1. In Example 5 of the present invention, θ1 was 5 degrees, and in Example 6 of the present invention, θ1 was 30 degrees. From Table 1, Invention Examples 5 and 6 showed Rmax slightly larger than Invention Example 1, but sufficient work material surface roughness was obtained. However, when θ1 is set to a larger value, a larger Rmax is expected. This is because chatter vibration and chipping occur when θ1 exceeds 30 degrees. On the other hand, when θ1 is less than 5 degrees, the interval between the inner peripheral cutting edge of the tool and the surface of the work material is narrowed, and there is a problem that chip biting occurs.
Inventive example 7 manufactured the tool by setting θ2 to 10 degrees, and in inventive example 8 to θ2 of 45 degrees, and only θ2 was changed with respect to inventive example 1. From the test results shown in Table 1, it was confirmed that a good finished surface roughness could be obtained if θ2 was in the range of 10 ≦ θ2 ≦ 45 degrees. Inventive Examples 9 to 12 are tools in which the tool shape parameters other than the r2 value of Inventive Example 1 have the same value. Invention Example 9 had r2 of 0.02 mm, Invention Example 10 had r2 of 0.2 mm, Invention Example 11 had r2 of 4 mm, and Invention Example 12 had r2 of 6 mm. From Table 1, in Example 9 of the present invention, at the point where the tool cutting edge ridge line at the lowest point of the tool changed from r1 to r2, since r2 was too small, scratches were generated on the surface of the work material during machining of the flat portion. In Inventive Example 10, since the value was larger than r2 in Inventive Example 9, no scratch was generated on the surface of the work material, and good surface roughness was exhibited. In Inventive Example 11, similar to Inventive Example 10, good work material surface roughness was shown, but in Inventive Example 12, scratches due to chip biting occurred and the surface roughness of the work material was shown. Adversely affected.
１：刃先交換式仕上げ用ラジアスエンドミル
２：ホルダー部
３：インサート
４：止めネジ
５：ネジ穴
６：直刃形状切刃
Ｄ：工具直径
Ｈ：切刃稜線部から２番逃げの開始点までの距離
Ｌ１：直線状外周刃
Ｌ２：直線状内周刃
Ｒ１ａ：円弧状外周刃
Ｒ１ｂ：円弧状外周刃
Ｒ２：円弧状内周刃
ａ：最外周点
ｂ：Ｒ１ａ領域とＲ１ｂ領域との境界点
ｃ：最下点
ｄ：内周刃上の点
ｅ：工具回転軸と内周刃との交点
ｆ：円弧状外周刃の円弧中心点
ｇ：円弧状内周刃の円弧中心点
ｒ１：円弧状外周刃の円弧半径
ｒ２：円弧状内周刃の円弧半径
β：バックテーパ角
θ１：最下点ｃの接線と点ｄの接線とのなす角度
θ２：Ｒ１ｂの中心角
θ３：逃げ角
θ４：２番逃げ角
1: Radius end mill for exchangeable cutting edge 2: Holder part 3: Insert 4: Set screw 5: Screw hole 6: Straight blade-shaped cutting edge D: Tool diameter H: From the edge of the cutting edge to the starting point of the second relief Distance L1: Linear outer peripheral edge L2: Linear inner peripheral edge R1a: Arc-shaped outer peripheral edge R1b: Arc-shaped outer peripheral edge R2: Arc-shaped inner peripheral edge a: Outermost peripheral point b: Boundary point between R1a region and R1b region c : Lowest point d: point on inner peripheral edge e: intersection of tool rotation axis and inner peripheral edge f: arc center point of arc outer peripheral edge g: arc center point of arc inner peripheral edge r1: arc outer periphery Arc radius of the blade r2: Arc radius of the arc-shaped inner peripheral blade β: Back taper angle θ1: Angle formed by the tangent of the lowest point c and the tangent of the point d θ2: Center angle of R1b θ3: Escape angle θ4: No. 2 Clearance angle
Claims (2)
The radius end mill for blade edge replaceable finishing according to claim 1, wherein the radius r2 of the other arcuate cutting edge of the insert is formed to have a relationship of 0.1≤r2≤5 (mm). A radius end mill for finishing with replaceable blades.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004141227A JP2005319558A (en) | 2004-05-11 | 2004-05-11 | Cutting edge replaceable-type finishing radius end mill |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004141227A JP2005319558A (en) | 2004-05-11 | 2004-05-11 | Cutting edge replaceable-type finishing radius end mill |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2005319558A true JP2005319558A (en) | 2005-11-17 |
Family
ID=35467206
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2004141227A Pending JP2005319558A (en) | 2004-05-11 | 2004-05-11 | Cutting edge replaceable-type finishing radius end mill |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2005319558A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009056533A (en) * | 2007-08-31 | 2009-03-19 | Hitachi Tool Engineering Ltd | Long neck radius endmill |
| JP2009202239A (en) * | 2008-02-26 | 2009-09-10 | Kyocera Corp | Rotary tool |
| JP2010110859A (en) * | 2008-11-06 | 2010-05-20 | Dijet Ind Co Ltd | Cutting edge exchange type end mill and throw away tip |
| JP2010162677A (en) * | 2009-01-19 | 2010-07-29 | Hitachi Tool Engineering Ltd | Small-diameter cbn ball end mill |
| EP2422907A1 (en) | 2010-08-27 | 2012-02-29 | Sandvik Intellectual Property AB | A milling insert, a tool and a device for milling |
| JP2013511394A (en) * | 2009-11-17 | 2013-04-04 | ケンナメタル インコーポレイテッド | Optimization of the cutting edge shape of a rounded nose end mill |
| US20160074947A1 (en) * | 2014-09-15 | 2016-03-17 | Iscar, Ltd. | End Mill Convex Radial Relief Surface and Corner Having Circular Arc Profile |
| JP2021504157A (en) * | 2017-11-30 | 2021-02-15 | イスカル リミテッド | Milling inserts capable of single-sided three-way indexing with a high ratio of void volume to material volume and insert mills for that purpose |
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2004
- 2004-05-11 JP JP2004141227A patent/JP2005319558A/en active Pending
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009056533A (en) * | 2007-08-31 | 2009-03-19 | Hitachi Tool Engineering Ltd | Long neck radius endmill |
| JP2009202239A (en) * | 2008-02-26 | 2009-09-10 | Kyocera Corp | Rotary tool |
| JP2010110859A (en) * | 2008-11-06 | 2010-05-20 | Dijet Ind Co Ltd | Cutting edge exchange type end mill and throw away tip |
| JP2010162677A (en) * | 2009-01-19 | 2010-07-29 | Hitachi Tool Engineering Ltd | Small-diameter cbn ball end mill |
| JP2013511394A (en) * | 2009-11-17 | 2013-04-04 | ケンナメタル インコーポレイテッド | Optimization of the cutting edge shape of a rounded nose end mill |
| US9308591B2 (en) | 2009-11-17 | 2016-04-12 | Leonid B. Sharivker | Optimization of cutting edge geometry in rounded nose end mills |
| CN102407370A (en) * | 2010-08-27 | 2012-04-11 | 山特维克知识产权股份有限公司 | Milling insert and tool and device for milling |
| EP2422907A1 (en) | 2010-08-27 | 2012-02-29 | Sandvik Intellectual Property AB | A milling insert, a tool and a device for milling |
| US8596934B2 (en) | 2010-08-27 | 2013-12-03 | Sandvik Intellectual Property Ab | Milling insert, a tool and a device for milling |
| US20160074947A1 (en) * | 2014-09-15 | 2016-03-17 | Iscar, Ltd. | End Mill Convex Radial Relief Surface and Corner Having Circular Arc Profile |
| US9517515B2 (en) * | 2014-09-15 | 2016-12-13 | Iscar, Ltd. | End mill convex radial relief surface and corner having circular arc profile |
| JP2021504157A (en) * | 2017-11-30 | 2021-02-15 | イスカル リミテッド | Milling inserts capable of single-sided three-way indexing with a high ratio of void volume to material volume and insert mills for that purpose |
| JP7324750B2 (en) | 2017-11-30 | 2023-08-10 | イスカル リミテッド | Single-sided, three-way indexable milling insert with high void volume to material volume ratio and insert mill therefor |
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