JP2004090148A - Cemented carbide end mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an end mill with a long service life that has high chip discharging property in machining a hole or a groove, has high surface roughness, provides a bright working surface, and has less melting even in dry cutting of an aluminum alloy. <P>SOLUTION: The three-blade cemented carbide end mill 1 has an equal bottom blade 2 where a bottom blade end gash is divided uniformly, center web of the central part of the bottom blade is set at 0.03 mm to 0.5 mm, minimum width of a bottom blade land is set at 0.03 mm to 0.5 mm, bottom blade end gash angle is set at 30° to 50°, bottom blade axial rake is set at 0° to 8°, and angle between a bottom blade rake face and the bottom face of the bottom blade end gash is set at 80° to 100°. Ratio of land width to groove width is set at 1:2 to 1:4, the blade groove 5 has a middle recessed round shape, central thickness is set at 45% to 55% of the outer diameter 19, and blade groove torsion angle 20 is set at 40° to 60°. In a case of having a neck, neck bottom length 9 is set three or more times of the outer diameter 19 of an outer peripheral cutting edge 3. In a blade part 8, a film such as titanium carbide is added to a first layer, and a film having physical property similar to that of diamond is added to a second layer (or first or second layer). <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a three-blade carbide end mill capable of continuous machining of a groove from drilling under high-efficiency conditions of high speed and high feed rate of an aluminum alloy, and a coating film of the end mill capable of dry cutting of the machining. Regarding improvement.
[0002]
[Prior art]
As disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-126934, a conventional three-blade carbide end mill includes an outer peripheral cutting edge 3 and a bottom blade 2 shown in FIG. 6, and as shown in FIG. One of the three bottom blades 22, 24, 25 is an unequal bottom blade, and one bottom blade 22 extends to the center. FIG. 8 shows a section perpendicular to the cutting edge 22a of the bottom blade 22. The bottom blade axial rake 15 is 3 ° to 9 °, and the angle formed by the bottom blade rake surface 17 and the bottom blade gash bottom surface 12 is 30 ° to 50 °. 9, the ratio of the land width L1 to the blade groove L2 is 1: 2 to 1: 4, and the core thickness 18 is 62% to 62% of the outer diameter 19 of the outer peripheral cutting edge 3 when viewed from the section perpendicular to the axis shown in FIG. 68%. The effective blade length 8 shown in FIG. 6 is two to three times the outer diameter 19 of the outer peripheral cutting edge 3.
[0003]
When machining an aluminum alloy with such a conventional carbide end mill, in order to prevent welding to a tool, the machining is usually performed while supplying a water-soluble cutting oil which enhances a lubricating action. However, in recent years, there has been an increasing demand for so-called dry working, which does not use a cutting oil for aluminum alloys by a carbide end mill, because of the spoilage of the water-soluble cutting oil and the difficulty of treating it as industrial waste.
[0004]
[Problems to be solved by the invention]
The first problem that occurs when cutting an aluminum alloy with a conventional carbide end mill is chip clogging of the blade groove 5. When drilling aluminum alloy with a conventional end mill, if the feed rate is increased to a certain degree or more, chips cut by the cutting edges 22, 24, and 25 of the bottom edge become difficult to be discharged. In particular, chips easily accumulate on the bottom blade 22 whose cutting edge 22a extends to the center, and the blade groove 23 formed by the bottom blade rake face 17 and the bottom blade gash bottom surface 12 and the blade groove 5 of the outer peripheral blade are formed. If it is completely filled, deeper hole processing or subsequent groove processing becomes impossible.
[0005]
Second, welding to the cutting edge of the tool. In a conventional carbide end mill tool, welding of an aluminum alloy is remarkable during dry working, and once welding starts, the machined surface is extremely deteriorated, and in the worst case, the tool is broken and the cutting becomes impossible. On the other hand, in a square type carbide end mill, as disclosed in JP-A-2001-293611, dry processing of an aluminum alloy is realized by applying a coating film having a small dynamic friction coefficient and improving welding resistance. I have. However, even if a similar coating film is applied to the conventional end mill shape shown in FIG. 6, the chips cut off by the cutting edge such as the bottom blade 22 are directly formed by the bottom blade rake face 17 and the bottom blade gash bottom face 12. There is a problem in that the blade groove 23 and the like to be clogged and fall into an unworkable state.
[0006]
Third, the machining of aluminum alloys has lower cutting resistance than iron-based materials, which allows for deeper pocket machining. However, in the conventional end mill, the effective blade length 8 is insufficient and machining is impossible.
[0007]
It is an object of the present invention to provide a three-blade carbide end mill which solves the problems of the conventional products described above, has excellent chip dischargeability in drilling and grooving, and has a good surface roughness and a glossy processed surface. Another object of the present invention is to provide a cemented carbide end mill capable of maintaining a long life and having good surface properties even when dry cutting an aluminum alloy.
[0008]
[Means for Solving the Problems]
As a result of research, the present inventor has adopted, in an end mill used for cutting a soft non-ferrous metal material such as an aluminum alloy, an equi-bottom blade in which a bottom blade gash is evenly distributed, and each cutting edge of the bottom blade. If a uniform amount is discharged, chip clogging can be prevented.Moreover, by providing a cutting edge almost at the center of the bottom blade, high efficiency drilling can be performed even with an end mill, When cutting non-ferrous metals such as aluminum alloys, we focus on the fact that cutting resistance is lower than that of ferrous materials. We have learned that an end mill that can realize high-efficiency machining by high feed can be obtained.
[0009]
Based on these knowledge, in the present invention, in a three-flute carbide end mill having a flute torsion angle on the outer circumference, the bottom blade gash is an even bottom blade evenly distributed, and the amount of remaining center of the bottom blade center portion is reduced. 0.03 mm to 0.5 mm, the minimum width of the bottom blade land is 0.05 mm to 0.3 mm, the bottom blade gash angle is 30 ° to 50 °, the bottom blade axial rake is 0 ° to 8 °, The angle between the rake face of the blade and the bottom face of the bottom gask is set to 80 ° to 100 °. Further, when viewed in a section perpendicular to the axis of the end mill cutting edge, the ratio of the land width L1 to the groove width L2 is 1: 2 to 1: 4, the blade groove in the cross section is a middle concave R shape, and the core thickness is the outer diameter. And the torsion angle of the blade groove is 40 ° to 60 ° (Claim 2). In addition, the above-mentioned problem has been solved by providing a carbide end mill in which the length under the neck, excluding the shank length from the total length, is three times or more the outer diameter of the outer peripheral cutting edge when the head is provided with a neck.
[0010]
That is, the bottom blade was as follows. An irregular-bottom blade is considered to have an equal-bottom blade because chips are easily clogged in the blade groove. If the centering amount of the bottom blade is less than 0.03 mm, the strength is insufficient. If the centering amount is larger than 0.5 mm, the drilling performance deteriorates, so the centering amount is set in the range of 0.03 mm to 0.5 mm. Similarly, if the minimum width of the bottom blade land is less than 0.05 mm, the strength is insufficient, and if the minimum width is more than 0.3 mm, the drilling performance deteriorates. Therefore, the unreserved amount is set in the range of 0.05 mm to 0.3 mm. When the bottom edge gash angle is less than 30 °, the chip pocket is small, and when the bottom edge gash angle exceeds 50 °, the cutting edge strength is reduced. Therefore, the bottom edge gash angle is set in the range of 30 ° to 50 °. Similarly, the bottom blade axial rake has a range of 0 ° to 8 ° because the sharpness is reduced when the angle is less than 0 °, and the edge strength of the cutting edge is reduced when the angle is more than 8 °. If the angle between the bottom blade rake face and the bottom blade gash bottom is less than 80 °, the chip pocket becomes smaller and the chip evacuation becomes worse, and if it is more than 100 °, the land width of the bottom blade becomes narrow and the strength becomes insufficient. , 80 ° to 100 ° (claim 1).
[0011]
Regarding the shapes of the outer peripheral edge and the neck portion, the ratio of land width to groove width is 1: 2 when viewed in a section perpendicular to the axis of the end mill cutting edge so as to obtain a shape having both sufficient rigidity and good chip evacuation. １ ： 1: 4, the blade groove in the cross section is formed into a concave R-shape, the core thickness is set to 45% to 55% of the outer diameter, the blade groove twist angle is set to 40 ° to 60 °, and further, the deep groove is formed. It is preferable to have a neck so that it can be machined, and the length of the neck under the neck, excluding the shank length from the total length, is at least three times the outer diameter of the outer peripheral cutting edge. With this configuration, the chip discharge grooves are widely and evenly arranged to obtain good chip discharge properties, have sufficient blade rigidity, and improve the processing performance of aluminum alloy semi-dry and wet processing.
[0012]
Further, in the invention of claim 4, a titanium carbide (TiC) or aluminum titanium nitride (TiAlN) coating film is formed on the blade portion of the carbide end mill as the first layer, and the physical properties similar to diamond are formed thereon. Titanium carbide (TiC / C), silicon carbide amorphous film (SiC / C), which has properties similar to diamond (SiC / C), chromium carbide film (CrC / C), or boron carbide film (BC / C) ) Was a carbide end mill to which the second layer coating film was added. As a result, the semi-dry and wet machining capabilities are further improved, and an end mill capable of performing dry machining is provided. Further, in the invention according to claim 5, both the first layer and the second layer have a silicon carbide type amorphous film (SiC / C) and a chromium carbide type film (CrC / C) having physical properties similar to diamond. Alternatively, a coating film of a boron carbide film (BC / C) may be added.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a three-blade carbide end mill showing an embodiment of the present invention, FIG. 2 is a bottom blade shape of the end mill of FIG. 1, and FIG. 3 is a partial enlarged view of a center portion of a carbide end mill bottom blade shown in FIG. FIG. 4 is a cross-sectional view taken along a line BB of FIG. 2, and a cross-sectional shape cut along a plane that intersects at right angles with the bottom rake face 17 and the bottom gask bottom 12 of the end mill 1. FIG. And a sectional shape cut along a plane perpendicular to the central axis within the range of the effective blade length 8 of the end mill 1. One of the outer peripheral cutting edges 3 is provided with a bottom blade 2, and the other is provided with a neck portion 6 and a shank 7 in order. In this example, the case where the outer diameter 19 of the outer peripheral cutting edge 3 is φ10 mm will be described. In FIG. 2, the bottom blade gash 12 is evenly distributed to the equal bottom blade 2, and in FIG. 3, the center remaining amount 13 of the bottom blade center portion is 0.2 mm, and the minimum width 14 of the bottom blade land is 0.15 mm. In FIG. 4, the bottom blade gash angle ρ (not shown, see JIS B 0172 6032) is 40 °, the bottom blade axial rake 15 is 4 °, and the angle 16 formed between the bottom blade rake face and the bottom blade gash bottom is 90 °. The bottom blade is formed so that it becomes. Next, in FIG. 5, the land width L1 of the flank 4 is set to 3.1 mm, the width L2 of the blade groove 5 is set to 6.1, the ratio between the land width and the blade groove width is set to 1: 2, and the core thickness 18 is set. Is set to 50%, and the blade groove 5 is formed so that the blade groove shape becomes a middle concave R shape. The helix angle 20 of the blade groove 5 is 45 °. Further, as shown in FIG. 1, a neck was attached, and a length 9 under the neck excluding the length of the shank 7 from the total length 10 was four times the outer diameter 19 of the outer peripheral cutting edge 3. It is more preferable that the neck diameter is 92% to 98% of the outer diameter of the outer peripheral cutting edge. In the embodiment of the present invention, the neck diameter 11 is 97% of the outer diameter of the outer peripheral cutting edge. The diameter 21 of the shank 7 is the same as the outer diameter 19, but it goes without saying that it may be different.
[0014]
Further, the cemented carbide end mill of the present invention according to the embodiment of the present invention uses an ultra-fine-grain cemented carbide of WC94.4%, Co5%, and other 0.6% as a base material, and at least FIG. A titanium carbide (TiC) or aluminum titanium nitride (TiAlN) coating film is formed on the first layer in the range of the blade portion 8 shown in FIG. 1 to secure wear resistance, and then carbonized material having properties similar to diamond is formed thereon. A second-layer coating film of a silicon-based amorphous film (SiC / C) is added to improve the adhesion resistance to an aluminum alloy. In the embodiment of the present invention, the coating film is applied, but for example, the degree of welding of the work material to the cutting edge using a cutting fluid is not subjected to surface treatment if there is no practical problem. It may be used as it is, and in the same embodiment, it is designed to have a neck that can be deeply carved, but if there is no need for deep carving, it may not be necessary to attach the neck like the conventional product Needless to say.
[0015]
【Example】
The present invention in which the chip discharge grooves shown in the above-described embodiment are widely and uniformly arranged, and a coating for improving the abrasion resistance and welding resistance and the blade groove shape for obtaining good chip discharge properties is applied. A comparative test was performed between a carbide end mill and a conventional carbide end mill. As a base material of a conventional cemented carbide end mill to be compared, a WC 90%, Co 8.5%, and other 1.5% ultra-fine cemented carbide was used. In the conventional product, the surface of the cutting edge portion is not coated or the like. An end mill outer diameter was set to φ10 mm, and a drilling feed speed limit performance test was performed on a rolled work material of aluminum A5052 with a hole depth of one time the outer diameter. FIG. 10 shows the processing results by dry processing and wet processing using a water-soluble cutting fluid at a cutting speed of 220 m / min (rotation speed: 7,000 min ⁻¹ ). In the result of the dry processing shown in FIG. 6A, the product of the present invention has a 2.5-fold increase of the conventional product, and in the result of wet processing of FIG. are doing.
[0016]
Next, the result of side-cutting a wall material having a height of 2.5 times the outer diameter and a length of 300 mm for the same work piece of A5052 will be described. As shown in FIG. 11, an end mill having an outer diameter of φ10 mm was used to perform processing by dividing the work into upper and lower stages. The cutting speed is 250m / min (S = 8,000m / min), the feed speed is 2,150mm / min, the axial depth of cut is 12mm, the upper level is 13mm, the radial depth of cut is 1mm, and the end mill protrusion is 42 mm. FIG. 12 shows the result of measuring the height of the wall surface, the feed direction of the end mill, and the surface roughness of the bottom surface, and FIG. 13 shows the result of measuring the inclination of the wall surface. According to these results, the product of the present invention has a maximum surface roughness Ry of about 3 to 5 μm as shown in FIG. Yes, and a good machined surface can be obtained. Further, as shown in FIG. 14, it was shown that the wall could be processed without falling down and the seam between the upper and lower sides could not be formed. On the other hand, the conventional one has a blade length of 22 mm, and it is impossible to machine a workpiece having a high wall height as shown in FIG.
[0017]
Further, as another processing example, an example in which high-efficiency deep carving processing with a depth of 4D is performed by dry cutting will be described. Using the product of the present invention having an end mill diameter of φ3 mm, pocket processing of 50 mm (length) × 60 mm (width) was performed in four steps of 3 mm in the depth direction. The cutting speed was 236 m / min (S = 25,000 m / min), the feed speed was 1,500 mm / min, the axial cut was 3 mm × 4 times, the radial cut was 0.3 mm, and the end mill protrusion amount was 12 mm. . As shown in the processing results in FIG. 14, high-efficiency deep carving processing with a depth of 4D is possible even in dry cutting, and a glossy processed surface is obtained. Conventionally, such high-efficiency processing of deep holes cannot be realized.
[0018]
【The invention's effect】
As described above, in the present invention, while ensuring the rigidity according to the aluminum processing, the chip discharge grooves of the bottom blade are widely and uniformly arranged with respect to the conventional product, so that good chip discharge performance is improved. It is possible to perform continuous machining from drilling to groove under high-speed and high-feed conditions.Furthermore, by applying a coating film that improves abrasion resistance and welding resistance, dry cutting of aluminum alloy is possible. In addition, a long life was maintained with little welding to the cutting edge, and processing with good surface properties became possible. High-efficiency machining is possible, and costs are reduced because no cutting oil is used. This has the effect of improving environmental friendliness.
[Brief description of the drawings]
FIG. 1 is a side view of a three-blade carbide end mill showing an embodiment of the present invention.
FIG. 2 is a bottom blade shape of a three-blade carbide end mill showing an embodiment of the present invention.
FIG. 3 is a partially enlarged view of a central portion of FIG. 2;
FIG. 4 is a cross-sectional view taken along a line BB of FIG. 2 of the three-flute carbide end mill showing the embodiment of the present invention, and has a cross-sectional shape cut along a plane that intersects perpendicularly with the bottom rake face and the bottom groove bottom. is there.
FIG. 5 shows a cross section taken along line AA of FIG. 1 of the three-flute carbide end mill showing the embodiment of the present invention, and has a cross-sectional shape cut along a plane perpendicular to a central axis within a range of an effective blade length. .
FIG. 6 is a side view of a conventional three-flute carbide end mill.
FIG. 7 is a bottom blade shape of a conventional three-blade carbide end mill.
8 shows a cross section taken along line DD of FIG. 7 of the conventional three-blade carbide end mill, and has a cross-sectional shape cut along a plane perpendicular to the bottom rake face and the bottom groove bottom.
9 shows a cross section taken along the line CC of FIG. 6 of the conventional three-blade carbide end mill, and has a cross-sectional shape cut along a plane perpendicular to the central axis within a range of the effective blade length.
10A and 10B show the results of a comparison of drilling performance between the product of the present invention and the conventional product, wherein FIG. 10A shows the result in the case of dry processing and FIG.
FIG. 11 shows a processing method when processing a wall surface having a height of 25 mm according to the present invention.
12 shows the results of measurement of the machined surface roughness when the product of the present invention is machined by the method shown in FIG. 11, (a) the bottom surface, (b) the axial direction of the wall surface (vertical direction in the figure), (C) is the feed direction (lateral direction in the figure) of the wall surface, Ra is the center line average roughness, Ry is the maximum surface roughness, and Rz is the 10-point average roughness.
FIG. 13 shows the result of measuring the inclination of the wall surface when processing the product of the present invention by the method shown in FIG. 11;
FIG. 14 is a photograph showing a workpiece processing surface when high-efficiency deep carving pocket processing is performed dry using the product of the present invention.
[Explanation of symbols]
1 End mill 2 Bottom blade (cutting edge)
3 Outer peripheral cutting edge 4 Outer peripheral flank 5 Outer peripheral blade groove 6 Below neck 7 Shank 8 Effective blade length (coating range)
9 Length under the neck 10 Total length 11 Neck diameter 12 Bottom edge gash bottom surface (bottom edge bottom groove)
13 Remaining amount of core 14 Minimum width of bottom blade land 15 Bottom blade axial rake 16 Angle between bottom blade rake face and bottom blade gash bottom 17 Bottom blade rake face 18 Core thickness 19 Outer diameter of outer peripheral cutting edge 20 Blade groove twist angle L1 Land width L2 Groove width (of the outer peripheral blade groove)

Claims (5)

In a three-flute cemented carbide end mill having a blade groove torsion angle on the outer periphery, the bottom blade gash is made an even bottom blade, and the remaining amount of the center of the bottom blade is 0.03 mm to 0.5 mm. The minimum width of the land is 0.03 mm to 0.5 mm, the bottom blade gash angle is 30 ° to 50 °, the bottom blade axial rake is 0 ° to 8 °, and the bottom blade rake surface and the bottom blade gash bottom surface are formed. A carbide end mill having an angle of 80 ° to 100 °. When viewed in a section perpendicular to the axis of the end mill cutting edge, the ratio of land width to groove width is 1: 2 to 1: 4, the blade groove is a concave R shape, and the core thickness is 45% to 55% of the outer diameter. 2. The cemented carbide end mill according to claim 1, wherein the helix angle of the blade groove is set to 40 [deg.] To 60 [deg.]. 3. The cemented carbide according to claim 1, wherein the cemented carbide end mill has a neck, and the length under the neck, excluding the shank length from the total length, is at least three times the outer diameter of the outer peripheral cutting edge. End mill. A titanium carbide (TiC) or aluminum titanium nitride (TiAlN) coating film is formed as a first layer on the blade portion of the carbide end mill, and a titanium carbide (TiC / C) having physical properties similar to diamond is formed thereon. A second layer coating film of a silicon carbide amorphous film (SiC / C), a chromium carbide film (CrC / C), or a boron carbide film (BC / C) with physical properties similar to diamond is added. The carbide end mill according to claim 1, 2 or 3, wherein: A silicon carbide-based amorphous film (SiC / C), a chromium carbide-based film (CrC / C) or a carbonized 4. The carbide end mill according to claim 1, wherein a coating film of a system boron film (BC / C) is added.

Images