JP4409665B2 - End mill with fluid supply hole - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an end mill with a fluid supply hole, and more particularly to an end mill with a fluid supply hole that can provide a good cooling action even in dry processing for supplying air as a fluid.
[0002]
[Prior art]
(a) a pair of long bottom blades provided near the shaft center along a pair of first gashes formed symmetrically with respect to the shaft center; and (b) from the pair of long bottom blades around the shaft center. A pair of short bottom blades provided along a second gash formed so as to reach the first gash from the outer periphery symmetrically with respect to the axial center at a position of 90 °. An equal bottom end mill is known. On the other hand, an end mill with a fluid supply hole for supplying a fluid such as a lubricant or air to a cutting site is described in, for example, Japanese Patent Application Laid-Open No. 61-25709. According to this, cutting performance (machining efficiency) and tool life such as pocket hole processing and grooving that are difficult to supply fluid from the outside are improved.
[0003]
[Problems to be solved by the invention]
By the way, in recent years, dry processing in which cutting is performed using air as a fluid has been desired due to problems such as processing of the lubricant, but since the cooling performance is lower than that of the lubricant, the conventional two-blade fluid In the end mill with a supply hole, the application range of the dry processing is narrow, and it is not always satisfactory.
[0004]
On the other hand, it has been difficult to provide four fluid supply holes in an end mill with four unequal bottom blades due to strength or manufacturing restrictions. Especially when the outer peripheral blade is a twisted blade twisted around the axis and the worn bottom blade is ground and reused, the fluid supply hole must also be a twisted hole twisted with the same lead as the twisted blade. In a relatively small-diameter end mill, it is difficult to provide three or more fluid supply holes for strength and manufacturing reasons.
[0005]
On the other hand, for example, it is conceivable that the fluid supply hole is opened only on the flank face of the pair of long bottom blades, but the short bottom blade to which the fluid is supplied from the flank face through the second gash has a good cooling action. However, since the fluid is not sufficiently supplied to the long bottom blade, it is not always possible to obtain sufficient cutting performance and tool life improvement effect. The same applies when a fluid supply hole is opened in the flank face of the pair of short bottom blades.
[0006]
The present invention has been made against the background of the above circumstances, and the object of the present invention is even when cutting is performed by supplying air from two fluid supply holes in an end mill having four unequal bottom blades. An object is to obtain a good cooling action and to obtain excellent cutting performance and tool life.
[0007]
[Means for Solving the Problems]
In order to achieve such an object, the first invention comprises (a) a pair of long bottom blades provided near the axis along a pair of first gashes formed symmetrically with respect to the axis; b) Provided at a position 90 ° from the pair of long bottom blades around the axis, along a second gash formed so as to reach the first gash from the outer periphery symmetrically with respect to the axis. An end mill having four unequal bottom blades having a pair of short bottom blades, and (c) having a pair of openings that open to the flank faces of the pair of long bottom blades, a fluid supply hole provided, (d) together with the ends of the axial center side is larger the communication area of the first gash and second gash intersect each other, crossing the first gash and second gash it like so as to connect the opening portion and the fluid supply hole And having a pair of communicating grooves kicked, the.
[0011]
【The invention's effect】
In the end mill with a fluid supply hole of the present invention , the fluid supply hole is provided so as to open to the flank of the pair of long bottom blades, and the first gash and the first gash with the end portions on the axial center side intersecting each other. Since a pair of communication grooves are provided so as to increase the communication area of the two gashes, and the fluid can easily flow between the two gashes, the fluid discharged from the pair of openings of the fluid supply holes is 4 All of the unequal bottom blades are supplied satisfactorily, and the cutting performance (working efficiency) and tool life are improved by the cooling action by the fluid. Thereby, even when air is supplied as a fluid, a good cooling action can be obtained, and the application range of dry processing is widened.
[0012]
In addition, since the communication groove is provided at the intersection of the first and second gashs where the end portions on the axis side intersect each other, the shaft side of the short bottom blade is cut by the communication groove. Although there is a possibility of shortening, the long bottom blade provided to the vicinity of the shaft center is not affected at all, and there is no possibility of impairing the cutting performance.
[0013]
The flank of the long bottom blade is provided with a pair of openings for fluid supply holes, and the communication grooves are connected to connect the openings of the fluid supply holes to the intersections of the first and second gashes. since is provided, for example, while the fluid from the gap between the opening and the work is supplied to the short end cutting edge to flow into the second gash side with the rotation of the end mill, the communication groove from the second gash through, or directly through the communication groove from the opening of the fluid supply hole, Ru is supplied to the long end cutting edge to flow into the first gash side.
[0015]
The size of the cross section of the communicating groove or (flow area), such as by the size of the gap between the opening and the work of the fluid supply hole, distribution channels of the fluid subtly varied, the opening of the test Kyuana through a flow or fluid from the gap between the workpiece to the second gash side, the flow is almost no fluid from the second gash to the first gash side, fluid discharged from the opening of the dedicated et communicating groove In some cases, the gas may branch into both gashes and flow, but as a result, it is sufficient that the fluid is satisfactorily supplied to the four unequal bottom blades.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is applied to various end mills such as a ball end mill and a square end mill. In addition, the outer peripheral blade continuously provided on the long bottom blade and the short bottom blade is a twisted blade twisted around the shaft center, and the fluid supply hole is also two twisted holes twisted with the same lead as the twisted blade, and is worn. Although it is preferably applied to an end mill that grinds and reuses the bottom blade, the outer peripheral blade is a straight blade and two linear fluid supply holes are provided in parallel to the shaft center, or one fluid The present invention can also be applied to the case where the supply hole is provided on the shaft center and is branched into two near the bottom blade. The material of the end mill is appropriately set such as cemented carbide or high speed steel.
[0017]
The end mill with a fluid supply hole of the present invention is suitably used for dry processing in which cutting is performed while air is supplied as a fluid, but it is needless to say that the end mill can also be used for wet processing in which a coolant is supplied as a fluid. In addition, it is suitably used for machining such as pocket hole machining and grooving where it is difficult to supply fluid from the outside, but it can also be used for other machining such as end face grinding, outer circumference grinding, and profile machining.
[0018]
The communication groove is provided, for example, at the end of the first gash at the axial center side, that is, at the intersection with the second gash, in a separate process from the first gash, and substantially parallel to the long bottom blade. Ru can also be provided communicating groove with the same working tool (such as grinding) in succession in the processing of the first gash before or after.
[0019]
Further, a communicating groove so as to include the opening of the fluid supply hole provided as necessary, fluid can be easily flows to the intersection portion of both gash. The shape of the long bottom blade and the short bottom blade in a bottom view can be made easier to flow to the axial center side by, for example, inclining the outer peripheral side toward the advancing side in the cutting rotation direction.
[0020]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
An end mill 10 with a fluid supply hole in FIG. 1 is an example when the present invention is applied to a square end mill with four unequal bottom blades, (a) is a front view seen from a direction perpendicular to the axis, and (b) ) Is a plan view seen from the shank 12 side, (c) is a bottom view seen from the blade part 14 side, and (d) is a perspective view of the blade part 14. The end mill 10 is made of a cemented carbide, and the shank 12 and the blade portion 14 are integrally provided continuously on the same axis, and the outer peripheral surface of the blade portion 14 is twisted around the axis. In addition, four outer peripheral twisting blades 18 are provided at equal angular intervals along the four twisting grooves 16. The shank 12 and the blade portion 14 are provided with two fluid supply holes (twisted holes) 20 twisted by the same lead as the outer circumferential twisted blade 18 at 180 ° intervals so as to pass through in the axial direction. By supplying fluid such as air or a cooling fluid from the rear end opening 20a on the shank 12 side, such fluid is discharged from the tip opening 20b on the blade portion 14 side.
[0021]
A pair of first gashs 22 is formed of a diamond grindstone or the like symmetrically with respect to the axis at the tip of the blade part 14, and a pair of long bottom blades 24 are provided along the first gash 22 to the vicinity of the axis. It has been. Further, a second gash 26 is formed with a diamond grindstone or the like so as to reach the first gash 22 from the outer periphery symmetrically with respect to the axis at a position 90 ° from the pair of long bottom blades 24 around the axis. A pair of short bottom blades 28 are provided along the second gash 26. The long bottom blade 24 and the short bottom blade 28 are provided so as to be connected to the outer peripheral twisting blade 18 at the outer peripheral edge. The first gash 22 constitutes the rake face of the long bottom blade 24, and the second gash 26 constitutes the rake face of the short bottom blade 28, and each has a groove depth direction ( It is provided so as to be inclined with respect to the axis in the tool axis direction).
[0022]
The front end opening 20 b of the fluid supply hole 20 is located at a boundary portion between the second surface and the third surface constituting the flank of the pair of long bottom blades 24. Since the fluid supply hole 20 and the outer peripheral twisting blade 18 are twisted by the same lead, even when the bottom blades 24 and 28 are ground and reused due to wear, the openings 20b with respect to the bottom blades 24 and 28 are used. The position is kept constant. In addition, the axial center substantially parallel to the long bottom blade 24 so as to connect the tip opening 20b and the intersecting portion of the end portions of the axial centers where the first gash 22 and the second gash 26 intersect each other. A pair of connection grooves 30 are provided symmetrically with respect to each other. Since the first gash 22 and the second gash 26 are connected to the intersection, the connecting groove 30 increases the communication area of the two gashes 22 and 26, and the connecting groove 30 also functions as a communication groove. The end mill 10 of the present embodiment is an embodiment of the second invention and the fourth invention.
[0023]
In such an end mill 10 with a fluid supply hole of this embodiment, a pair of fluid supply holes 20 are provided so as to open to the flank faces of the pair of long bottom blades 24, and the tips of the fluid supply holes 20 are provided. Since the connection groove 30 is provided so as to connect the opening 20b and the intersecting portions of both the gashes 22 and 26, the fluid discharged from the tip opening 20b is, for example, a flank (tip) as the end mill 10 rotates. While flowing through the gap between the opening 20b) and the workpiece to the second gash 26 side and supplied to the short bottom blade 28, the second gash 26 passes through the intersecting portion of the first gash 22 with the second gash 26. Since it flows to the 1st gash 22 side or flows directly from the connection groove 30 to the 1st gash 22 side and is supplied to the long bottom blade 24, all four unequal bottom blades 24 and 28 are excellent in fluidity. But So it is fed.
[0024]
Depending on the cross-sectional size (flow area) of the connection groove 30 and the size of the gap between the tip opening 20b of the fluid supply hole 20 and the workpiece, the fluid flow path slightly changes. There is almost no fluid flow from the gap between the workpiece to the second gash 26 side and no fluid flow from the second gash 26 to the first gash 22 side, and the fluid discharged from the tip opening 20b is exclusively connected grooves. In some cases, the gas flows into the gashs 22 and 26 through the gas flow 30. However, it is only necessary that the fluid is satisfactorily supplied to the four unequal bottom blades 24 and 28 as a result.
[0025]
As described above, according to the end mill 10 with the fluid supply holes of the present embodiment, the fluid is satisfactorily received from the two fluid supply holes 20 to all of the four unequal bottom blades 24 and 28 due to the presence of the communication groove 30. Therefore, cutting performance (machining efficiency) and tool life are improved by the cooling action by the fluid, etc., so that even when air is supplied as a fluid, a good cooling action can be obtained, and the application range of dry machining Becomes wider.
[0026]
Further, since the connection groove 30 is provided at the intersection of the first gash 22 and the second gash 26 substantially in parallel with the long bottom blade 24, the long bottom blade 24 and the short bottom blade 28 have no influence. There is no risk of impairing cutting performance.
[0027]
Next, as in the end mill 10 of the above embodiment, two fluid supply holes are opened on the flank face of the long bottom blade, and a pair of openings is connected so that the tip opening and the intersection of both gashes are connected. Four-blade square end mill with a connection groove (product of the present invention), two-blade square end mill with two fluid supply holes (conventional product I), and no fluid supply hole The results of a cutting performance test using a two-blade square end mill (conventional product II) will be described. Each of the three types of end mills has a nominal diameter of φ10, a twist angle of the outer twist blade of about 30 °, a bottom blade rake angle of 10 °, a bottom blade second angle of 6 °, and a bottom blade third angle of 12 °. The corner R of the product of the present invention and the conventional product I is 0.4 mm, and the corner R of the conventional product II is 0.5 mm. In addition, air was supplied from a fluid supply hole for the product of the present invention and the conventional product I, and air was supplied using an external nozzle for the conventional product II. The processing conditions are as follows.
(Processing conditions)
Projection dimension: 40mm Holder: DTC Machining method: Helical hole machining Material: SKD61 (40HRC) Machine: Horizontal machining center Rotational speed: 6500min- ¹ Feed speed: 0.4mm Z feed amount per revolution (hole depth direction) Feed amount): 0.4 mm Processing hole depth: 18 mm Processing hole diameter: φ15
[0028]
And the result of having investigated the relationship between the abrasion amount of the outer periphery corner part of a bottom blade, and a cutting distance is shown in FIG. In the figure, “◯” is the product of the present invention, “□” is the conventional product I, “×” is the conventional product II, and according to the product of the present invention, the amount of wear is small even when the cutting distance is 2000 mm or more. Excellent tool life is obtained. Further, when the cutting distance is about 1500 mm or less, the wear amount is substantially the same as that of the conventional product I, but the surface roughness of the product of the present invention was superior. The cutting distance corresponds to the number of cutting holes and is about 1000 mm with 28 holes.
[0029]
FIG. 3 shows a comparison of “internal air” when air is supplied from the fluid supply hole and “internal cooling oil” when cooling oil (water-soluble emulsion type) is supplied from the fluid supply hole. “●” and “◯” are both 0.4 mm in feed speed and Z feed per revolution, and “■” and “□” are both 0 in feed speed and Z feed per revolution. .6 mm. Except for the feed amount and the Z feed amount per revolution, the other processing conditions are the same as in the case of FIG. As is clear from FIG. 3, when the feed rate and the Z feed amount per revolution are 0.6 mm, the dry processing (■) with internal air is more effective than the wet processing (□) using the coolant. However, when the feed rate and the Z feed amount per revolution were 0.4 mm, the cooling oil was used until the cutting distance exceeded 2000 mm even in dry processing (●) with internal air. Excellent tool life is obtained with the same amount of wear as wet processing (◯). In this case as well, the cutting distance corresponds to the number of cutting holes and is about 1000 mm with 28 holes.
[0030]
FIG. 4 shows that a pair of fluid supply holes are opened on the flank face of the long bottom blade as in the end mill 10 of the above embodiment, and the tip opening is connected to the intersection of both gashes. A square end mill ( product of the present invention ) with four non-uniform bottom blades provided with a connecting groove and two fluid supply holes 20 as shown in FIG. A square of four unequal bottom blades that are opened at the bottom of the first gash 22 and are provided with a pair of connection grooves 32 so as to connect the tip opening 20b and the intersection of the gashs 22 and 26. Using an end mill (comparative product) , the “internal air” when air was supplied from the fluid supply hole and the “internal cooling oil” when cooling oil (water-soluble emulsion type) was supplied from the fluid supply hole were compared. With "●" and ""In the case of the product of the present invention," ■ "and" □ "is the case of the comparative product. The product of the present invention and the comparative product are both nominally φ12, bottom blade rake angle 10 °, bottom blade second angle 6 °, bottom blade third angle 12 °, corner R 0.5 mm. The processing conditions are as follows.
(Processing conditions)
Projection dimension: 40mm Holder: DTC Machining method: Helical hole machining Material: SKD61 (40HRC) Machine: Horizontal machining center Rotational speed: 5305min- ¹ Feed rate: 0.6mm Z feed amount per revolution: 0.6mm Hole depth: 24mm Processing hole diameter: φ18
[0031]
As is clear from FIG. 4, the tool life in dry processing (■, ●) with internal air is markedly impaired compared with wet processing (□, ○) using a cooling oil in either case. In machining, the fluid supply hole is opened at the bottom of the first gash located on the flank face side of the short bottom blade, compared to the present invention product ( ○) where the fluid supply hole is opened at the flank face of the long bottom blade. comparative (□) less overall wear amount toward the first gash bottom openings to have comparative of the fluid supply hole in dry machining positioned on flank side of the short end cutting edge (■) than The product of the present invention ( ●) with the fluid supply hole opening on the flank of the long bottom blade has a longer tool life. In the comparative dry processing (■), the further processing with 7 holes became impossible by welding. Also in this case, the cutting distance corresponds to the number of cutting holes and is 960 mm with 40 holes.
[0032]
In the comparative product, the fluid discharged from the tip opening 20b into the first gash 22 is quickly supplied to the long bottom blade 24, while the connecting groove 32 facilitates fluid flow to the axial center side, and the first gash 22 Since the communication area between the first gash 22 and the second gash 26 is expanded, the fluid flows favorably from the first gash 22 to the second gash 26 and is supplied to the short bottom blade 28. the end cutting edge 24, 28 it improved suitably cooled by cutting performance (processing efficiency) and tool life.
[0033]
In the above description, the case where the present invention is applied to a square end mill having four unequal bottom blades has been described. However, the present invention can also be applied to a ball end mill having four unequal bottom blades as shown in FIG. . The end mill 40 is different or the ball end mill or a square end mill is compared to the end mill 10, since the end cutting edge shape is only different, you omit detailed description are denoted by the same reference numerals.
[0034]
As mentioned above, although the Example of this invention was described in detail based on drawing, these are one embodiment to the last, and this invention is implemented in the aspect which added the various change and improvement based on the knowledge of those skilled in the art. be able to.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram for explaining an example when the present invention is applied to a square end mill having four unequal bottom blades, where (a) is a front view seen from a direction perpendicular to the axis, and (b) is a shank. The top view seen from the side, (c) is the bottom view seen from the blade part side, (d) is the perspective view of a blade part.
FIG. 2 is a diagram showing a result of investigating a relationship between a cutting distance and a corner portion wear amount by performing helical drilling by dry machining using the product of the present invention and a conventional product.
FIG. 3 is a diagram showing a result of examining a relationship between a cutting distance and a corner wear amount by performing dry processing and wet processing using the product of the present invention.
FIG. 4 is a diagram showing a result of examining a relationship between a cutting distance and a corner wear amount by performing dry processing and wet processing using a product of the present invention and a comparative product having different opening positions of fluid supply holes.
FIG. 5 is a bottom view when the opening of the fluid supply hole is provided at the bottom of the first gash located on the flank side of the short bottom blade.
6 is a view for explaining an example when the present invention is applied to a ball end mill having four unequal bottom blades, and corresponding to FIG. 1. FIG.
[Explanation of symbols]
10, 40: End mill with fluid supply hole 20: Fluid supply hole 20b: Tip opening (opening) 22: First gash 24: Long bottom blade 26: Second gash 28: Short bottom blade 30: Connection groove (communication groove)

Claims (1)

A pair of long bottom blades provided near the axis along a pair of first gashes formed symmetrically with respect to the axis;
A pair provided around a shaft at a position 90 ° from the pair of long bottom blades along a second gash formed so as to reach the first gash from the outer periphery symmetrically with respect to the shaft. With a short bottom blade,
In an end mill with four unequal bottom blades having
A fluid supply hole provided vertically through the end mill, having a pair of openings that open to the flank of the pair of long bottom blades;
The communication area of the first gash and the second gash whose end portions on the axial center side cross each other is increased , and the intersection of the first gash and the second gash and the opening of the fluid supply hole are connected. a pair of communicating groove provided so as,
An end mill with a fluid supply hole.

Images