CN220028800U

CN220028800U - Spiral groove forming milling cutter

Info

Publication number: CN220028800U
Application number: CN202321085227.1U
Authority: CN
Inventors: 张新奇
Original assignee: Egrite Cutting Technology Shanghai Co ltd
Current assignee: Egrite Cutting Technology Shanghai Co ltd
Priority date: 2023-05-08
Filing date: 2023-05-08
Publication date: 2023-11-17
Anticipated expiration: 2033-05-08

Abstract

The utility model provides a spiral flute forming milling cutter, which is provided with a plurality of cutting edges and a plurality of main flutes corresponding to the cutting edges, wherein the cutting edges are respectively provided with a rake face, a relief face and a cutting edge independently, the rake face forms a first rake angle at each position of the cutting edge, the main flutes are spiral flutes, auxiliary flutes are arranged on the rake face and extend along the direction of the negative angle face cutting edge in the length direction, and the auxiliary flutes are provided with flute faces close to the negative angle face cutting edge, so that the flute faces of the auxiliary flutes close to the negative angle face cutting edge form a negative angle face second rake angle which is larger than the corresponding first rake angle. The secondary chip flute is arranged to form the second rake angle, so that the problem that the negative rake angle or the rake angle of the cutting edge of the spiral flute forming milling cutter is too small can be effectively solved, the negative rake angle is changed into the positive rake angle, the cutting efficiency is greatly improved, the cutting resistance is reduced, and the service life of the cutter is prolonged.

Description

Spiral groove forming milling cutter

Technical Field

The utility model relates to the technical field of milling cutters, in particular to a spiral groove forming milling cutter.

Background

The milling cutter is a multi-tooth multi-edge rotary cutter with wide application. During milling, the milling cutter rotates around the axis of the milling cutter and moves mainly, and the workpiece moves in a feeding mode. Since the milling cutter is generally used for high-speed cutting, the milling cutter has high impact and high vibration during machining. The milling cutter is a multi-edge cutter, has high milling speed and no idle stroke, so that the milling cutter is a high-efficiency cutting machining method. A formed milling cutter is a milling cutter whose cutting edge profile is calculated based on the shape design of the formed surface of the workpiece. The formed milling cutter can be used for machining planes, grooves and steps, threads, splines, gears and other formed surfaces. The formed milling cutter in the prior art has the problem that the cutting speed and the structural strength cannot be considered. Particularly, the high-precision blade disc, blade and impeller of the aircraft engine component and the turbine component are machined, the requirements on the performance of the cutter are extremely high, the cutter in the prior art cannot meet the requirements on machining precision, cutting speed, service life and the like, and the production progress of the items is restricted. In the prior art, a cutter made of high-speed steel and hard alloy materials is usually used, the cutting edge of the high-speed steel is more sharp because of good toughness, but the cutter is difficult to process at a high linear speed due to the characteristics of the high-speed steel materials, and the service life of the high-speed steel milling cutter is short. The hard alloy is high-temperature resistant, is suitable for high-linear-speed machining, is limited by the existing cutter manufacturing process, cannot meet the sharp large rake angle requirement of the cutting edge required by the formed milling cutter, has poor cutter machining precision, low cutting efficiency and short service life, and cannot meet the industrial requirements. There is a need for improvements in the machining efficiency, machining accuracy, and machining life of tools.

Disclosure of Invention

The utility model provides a spiral groove forming milling cutter and a method for increasing sharpness of the spiral groove forming milling cutter, comprising the following implementation modes:

embodiment 1. A helical flute forming mill comprising a forming mill body portion and optionally a connecting portion for direct or indirect connection to a machine tool, at least the forming mill body portion being of unitary cemented carbide material, the forming mill body portion having a plurality of cutting edges and a plurality of major chip flutes corresponding to the cutting edges, the cutting edges each independently having a rake face, a relief face and a cutting edge, the rake face forming a first rake angle at each of the cutting edges, the major chip flutes being helical flutes, each of the cutting edges comprising at least one cutting tooth, the relief faces of the cutting teeth being divided into negative, positive and side faces so as to correspond to three cutting edges, namely a negative, positive and side edges, characterized in that a minor chip flute is provided on the rake face, the minor chip flute extending lengthwise in the direction of the negative face, the minor chip flute having a flute side adjacent the negative face such that the negative face forms a major rake angle adjacent the second rake angle to the negative face. In some embodiments, wherein the rake surface is formed by a radius passing perpendicularly through the shaped milling cutter axis.

Embodiment 2. The helical flute forming milling cutter of embodiment 1, wherein the negative rake face second rake angle is 3 to 65 degrees, such as 5 to 35 degrees, such as 3 to 35 degrees, greater than the first rake angle.

Embodiment 3. The helical flute forming milling cutter according to embodiment 1, wherein the angle of the helical flute is the angle between the direction of the helix and the main axis, the angle of the helical flute being between 3 and 55 degrees, such as 15 degrees to 50 degrees, such as 25 degrees to 45 degrees; the secondary chip flute also extends in a length direction along the direction of the side cutting edge, the secondary chip flute having a flute face proximate the side cutting edge such that the flute face of the secondary chip flute proximate the side cutting edge forms a side second rake angle that is greater than the corresponding first rake angle.

Embodiment 4. The helical flute forming milling cutter according to embodiment 2, wherein the secondary chip flute extends along the entire cutting edge such that all actual rake angles are 5 degrees or more and 45 degrees or less, 10 degrees or more and 35 degrees or less, 15 degrees or less and 25 degrees or 27 degrees or less and 40 degrees or less.

Embodiment 5. The helical flute forming milling cutter according to embodiment 1, wherein the secondary flutes have a width of 0.15mm to 3mm or 3% to 30% of the milling cutter diameter.

Embodiment 6. The helical flute forming milling cutter according to embodiment 1, wherein the depth of the secondary chip flute is 0.1 to 2mm, or 0.3 to 1.5mm.

Embodiment 7. The helical flute forming milling cutter according to embodiment 1, wherein the flute surfaces of the secondary flutes adjacent to the negative angle face cutting edge and/or the flute surfaces adjacent to the side face cutting edge extend in a wavy manner in the direction of the cutting edge, or wherein the secondary flutes have flute bottom surfaces which connect with the flute surfaces adjacent to the negative angle face cutting edge and/or the flute surfaces adjacent to the side face cutting edge and are substantially parallel to the rake surface, the flute bottom surfaces undulate in a wavy manner.

Embodiment 8 the helical flute forming milling cutter of embodiment 1, wherein the milling cutter has a diameter of 5mm to 80mm, such as 5mm to 50mm, such as 8mm to 40mm,10mm to 30mm.

Embodiment 9. The helical flute forming milling cutter according to embodiment 1, wherein the secondary chip flute is produced by a processing method that does not cause thermal damage.

Embodiment 10. The helical flute forming milling cutter according to embodiment 1, wherein the secondary chip flute is produced by a femtosecond pulse laser machining method.

Embodiment 11. A method of increasing sharpness of a helical flute forming milling cutter,

wherein the helical flute forming mill comprises a forming mill body portion and optionally a connecting portion for direct or indirect connection to a machine tool, at least the forming mill body portion being of unitary cemented carbide material, the forming mill body portion having a plurality of cutting edges and a plurality of primary chip flutes corresponding to the cutting edges, the cutting edges each independently having a rake face, a relief face and a cutting edge, the rake face forming a first rake angle at each of the cutting edges, the primary chip flutes being helical flutes, each of the cutting edges comprising at least one cutting tooth, the relief faces of the cutting teeth being divided into negative, positive and side faces so as to correspond to three cutting edges, namely a negative, positive and side cutting edges,

the method comprises the following steps: and forming an auxiliary chip flute on the front cutter surface, wherein the auxiliary chip flute extends along the direction of the negative angle surface cutting edge in the length direction, and the auxiliary chip flute is provided with a flute surface close to the negative angle surface cutting edge, so that the flute surface of the auxiliary chip flute close to the negative angle surface cutting edge forms a negative angle surface second rake angle, and the negative angle surface second rake angle is larger than the corresponding first rake angle. In some embodiments, the rake surface is formed by a radius passing perpendicularly through the shaped milling cutter axis.

Embodiment 12. The method of embodiment 11 wherein the negative angle face second rake angle is 3 degrees to 65 degrees, such as 5 degrees to 35 degrees, such as 3 degrees to 35 degrees, greater than the first rake angle.

Embodiment 13. The method of embodiment 11, wherein the angle of the helical groove is the angle between the direction of the helix and the main axis, the angle of the helical groove being between 3 and 55 degrees, such as 15 degrees to 50 degrees, such as 25 degrees to 40 degrees; the secondary chip flute also extends in a length direction along the direction of the side cutting edge, the secondary chip flute having a flute face proximate the side cutting edge such that the flute face of the secondary chip flute proximate the side cutting edge forms a side second rake angle that is greater than the corresponding first rake angle.

The method of embodiment 14, wherein the secondary flutes extend along the entire edge such that all actual rake angles are greater than or equal to 5 degrees to less than or equal to 45 degrees, greater than or equal to 10 degrees to less than or equal to 35 degrees, greater than or equal to 15 degrees to less than or equal to 25 degrees, or greater than or equal to 25 degrees to less than or equal to 40 degrees.

Embodiment 15. The method of embodiment 11, wherein the secondary flutes have a width of 0.15mm to 3mm or 3% to 30% of the milling cutter diameter.

Embodiment 16. The method of embodiment 11, wherein the secondary flutes have a depth of 0.1 to 2mm, or 0.3 to 1.5mm.

Embodiment 17. The method according to embodiment 11, wherein the flute surfaces of the secondary flutes adjacent to the negative angle surface cutting edge and/or the flute surfaces adjacent to the side surface cutting edge extend in a wave-like manner in the direction of the cutting edge, or wherein the secondary flutes have flute bottom surfaces that connect with the flute surfaces adjacent to the negative angle surface cutting edge and/or the flute surfaces adjacent to the side surface cutting edge and are substantially parallel to the rake surface, the flute bottom surfaces undulate in a wave-like manner.

Embodiment 18. The method of embodiment 11, wherein the milling cutter has a diameter of 5mm to 80mm, e.g. 5mm to 50mm, e.g. 8mm to 40mm,10mm to 30mm.

Embodiment 19. The method of embodiment 11, wherein the secondary flutes are formed by a processing method that does not cause thermal damage.

Embodiment 20. The method of embodiment 11, wherein the secondary flutes are produced using a femtosecond pulsed laser machining method.

According to the application, the auxiliary chip flute is arranged, and extends along the negative angle surface cutting edge, or extends along the direction of the side surface cutting edge, or extends along the whole cutting edge, so that the flute surface of the auxiliary chip flute, which is close to the negative angle surface cutting edge, forms a negative angle surface second rake angle which is larger than a corresponding first rake angle, and forms a side surface second rake angle on the flute surface, which is close to the side surface cutting edge, or all actual rake angles are in a specific range, thereby effectively solving the problems of the negative rake angle or the too small rake angle of the cutting edge of the spiral flute forming milling cutter, and improving the rake angle of the cutting edge, thereby enabling cutting to be lighter and faster, effectively reducing cutting resistance, enabling the processing precision to be higher, enabling the service life of the cutter to be more durable, and enabling the cutter to maintain the processing precision even when the cutter is used for a long time. The application further enhances the integral strength of the milling cutter and the linear speed during processing by arranging the wavy extending groove surface and/or the wavy undulating groove bottom surface, thereby improving the processing efficiency. The service life of the milling cutter adopting the technical scheme of the application is 2-5 times of that of the cutter in the prior art.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following brief description of the drawings of the embodiments will make it apparent that the drawings in the following description relate only to some embodiments of the present disclosure, not to limit the present disclosure.

FIG. 1 is a perspective view of a helical flute forming milling cutter;

FIG. 2 is a schematic view of a body portion of a helical flute forming milling cutter;

FIG. 3 is a front view of a portion of a helical flute forming milling cutter body;

FIG. 4 is a partial cross-sectional view of a helical flute forming milling cutter;

FIG. 5 is a cross-sectional view A-A of the helical flute forming milling cutter of FIG. 4;

FIG. 6 is an enlarged partial schematic view of the dashed box of FIG. 5;

FIG. 7 is an enlarged partial schematic view of the dashed box of FIG. 4;

FIG. 8 is a B-B cross-sectional view of the helical flute forming cutter cutting tooth of FIG. 7;

FIG. 9 is a schematic view of the wavy groove surface and the groove bottom provided in example 3;

FIG. 10 is a schematic view of a body portion of a helical flute forming milling cutter of example 5;

fig. 11 is a schematic view illustrating that the rake surface is formed by a radius perpendicular through the axis of the formed cutter.

Description of the drawings: 10-auxiliary chip flute, 11-flute face, 12-flute bottom face, 20-body portion, 30-connecting portion, 100-cutting edge, 110-rake face, 120-flank face, 121-negative angle face, 122-positive angle face, 123-flank face, 130-edge, 131-negative angle face edge, 132-positive angle face edge, 133-flank edge, 200-main chip flute, 300-cutting tooth.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present disclosure more apparent, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present disclosure. It will be apparent that the described embodiments are some, but not all, of the embodiments of the present disclosure. All other embodiments, which can be made by one of ordinary skill in the art without the need for inventive faculty, are within the scope of the present disclosure, based on the described embodiments of the present disclosure.

The application discloses a spiral flute forming milling cutter, which comprises a forming milling cutter body part and an optional connecting part for being directly or indirectly connected with a machine tool, wherein at least the forming milling cutter body part is made of integral hard alloy materials, the forming milling cutter body part is provided with a plurality of cutting edges and a plurality of main chip flutes corresponding to the cutting edges, the cutting edges are respectively provided with a rake face, a relief face and cutting edges, each rake face forms a first rake angle at each cutting edge, the main chip flutes are spiral flutes, each cutting edge comprises at least one cutting tooth, the relief face of each cutting tooth is divided into a negative angle face, a positive angle face and a side face, and thus, three cutting edges, namely a negative angle face cutting edge, a positive angle face cutting edge and a side cutting edge, are respectively arranged on the rake face, and the auxiliary chip flutes extend along the direction of the negative angle face in the length direction, and are provided with flute auxiliary cutting edges adjacent to the negative angle face, so that the negative angle face is adjacent to the second rake angle cutting edge, and the negative angle cutting edges are adjacent to the first rake angle face and the second rake angle cutting edge is larger than the first rake angle cutting edge.

In some embodiments, the rake surface is formed by a radius passing perpendicularly through the shaped milling cutter axis. In the present application, the expression "the rake surface is formed by a radius passing perpendicularly through the axis of the shaped milling cutter" means that a perpendicular to the axis of the shaped milling cutter is made from any point of the cutting edge, which perpendicular falls onto the rake surface. As shown in fig. 11, the points shown in the drawing are the points on the cutting edge and the rake face, the inclined straight line being the axis of the formed cutter, wherein perpendicular lines perpendicular to the axis of the formed cutter are made from any point on the cutting edge, which lines constitute the rake face or which lines fall onto said rake face. The design makes the position of the cutting edge on the vertical line, and the scaling of the position of the cutting edge is the scaling amount of the radius at the position, so that the precision of the contour line of the cutter can be effectively ensured. In some embodiments, the precision of the tool itself may be up to 0.002-0.003mm, i.e. 2-3 microns. This is because the sharpness of the tool according to the present application does not depend entirely on the setting of the rake face, but can be improved by the auxiliary chip pocket after setting the exact rake face. The accurate front tool face is convenient to manufacture, the precision of the contour line of the tool can be guaranteed, the precision of a machined workpiece is related, and meanwhile, the sharpness of the auxiliary chip flute is improved, so that the precision is guaranteed, and the sharpness is guaranteed. In the prior art, by integrally grinding the rake face into a sharper acute angle, all rake angles cannot be actually made into acute angles, and the grinding makes the vertical line from the contour line of the cutting edge of the cutter to the axis not be on the rake face, so that the contour line is more complex, the processing becomes more complex, the control of precision becomes more difficult, the precision of the cutter and the processed workpiece is easily deteriorated, and the sharpness is not fully improved.

In the present application, a milling cutter for machining a formed surface, the cutting edge profile of which is designed according to the profile of a workpiece, is called a formed milling cutter.

The "first rake angle" in the present application refers to a value obtained by subtracting the included angle between the rake face and the flank face from 90 degrees without making a clearance design. The larger the value of the first rake angle, the sharper the edge. And (3) making a plane perpendicular to the cutting edge at the cutting edge, wherein an included angle between the intersection line of the plane and the rake face and the flank face at the cutting edge is the included angle between the rake face and the flank face under the condition that no clearance design is made.

The second rake angle in the application is a value obtained by subtracting an included angle between a groove surface of the auxiliary chip groove, which is close to the cutting edge, and a rear cutter surface under the condition that no clearance design is made. And (3) making a plane perpendicular to the cutting edge at the cutting edge where the auxiliary chip flute is arranged, wherein the included angle between the plane and the cutting edge of the intersection line of the flute surface, close to the cutting edge, of the auxiliary chip flute and the rear cutter surface is the included angle between the flute surface, close to the cutting edge, of the auxiliary chip flute and the rear cutter surface under the condition of no clearance design. For some selected points on the cutting edge, there are both a first rake angle and a second rake angle, where the first rake angle is the corresponding first rake angle of the second rake angle for the selected point on the cutting edge.

In the present application, "negative angle face", "positive angle face" and "side face" are used to describe different regions of the flank face of one cutting tooth, where "negative angle face" is located in a region where the first rake angle formed at the corresponding cutting edge is negative, where "positive angle face" is located in a region where the first rake angle formed at the corresponding cutting edge is positive, and where "side face" is a region between the positive angle face and the negative angle face. The spiral of the spiral groove in the application can be left-handed or right-handed, and the negative angle surface and the positive angle surface of the cutting tooth are positioned relative to the direction of the spiral groove in normal conditions, and the negative angle surface is a near-axis surface, namely a surface of the cutting tooth which is closer to the main shaft of the machine tool, and the positive angle surface is a far-axis surface, namely a surface of the cutting tooth which is farther from the main shaft of the machine tool, for the selected cutting tooth in the case that the spiral groove is left-handed. In the case of a right-handed helical flute, the negative angle surface is the far axis surface, i.e., the surface of the cutting tooth farther from the machine tool spindle, and the positive angle surface is the near axis surface, i.e., the surface of the cutting tooth closer to the machine tool spindle. It will be appreciated by those skilled in the art that the negative angle face, positive angle face, side face divisions, and the corresponding negative angle face cutting edge, positive angle face cutting edge, and side face cutting edge definitions are provided for convenience only and should not be construed as limiting the application, e.g., the application defines the side face as the region between the positive and negative angle faces, but should not be construed as defining the first rake angle of the side face cutting edge as 0 degrees, and the side face is located between the proximal and distal axis faces, as would be understood by those skilled in the art, with the corresponding first rake angle of the side face cutting edge either being positive or negative, or transitioning gradually from positive to negative or from negative to positive. All examples of the application are presented with a left-handed helical groove, but it will be understood by those skilled in the art that similar designs are made on the basis of a right-handed helical groove, or on the basis of a helical groove containing both left and right-handed helical grooves, are fully understood by those skilled in the art and do not require any undue effort, and are within the intended scope of the application.

In the present application, the "negative angle surface second rake angle" refers to a second rake angle formed at an arbitrary selected point of the cutting edge to which the negative angle surface corresponds.

In the application, the cutting edge rake angle of any selected point of the cutting edge meeting the sharpness requirement of the formed milling cutter is defined as an actual rake angle, which is an index for measuring the sharpness of the formed milling cutter in the working state of the application, the actual rake angle of any selected point of the cutting edge meeting the sharpness requirement of the formed milling cutter without arranging a secondary chip flute is a first rake angle of the selected point, and the actual rake angle of any selected point of the cutting edge provided with the secondary chip flute to meet the sharpness requirement of the formed milling cutter is a second rake angle of the selected point.

The first rake angle of the helical flute forming mill comprises a value greater than 0, equal to 0 and less than 0, and in the case of a first rake angle less than 0, i.e., a negative angle face region corresponding to a negative angle of the first rake angle at the cutting edge, the sharpness of the mill is insufficient, and during milling, the corresponding cutting edge portion is subjected to a large force and is severely worn, resulting in a short life of the mill. According to the application, the secondary chip flute extending along the direction of the negative angle surface cutting edge is arranged to form the negative angle surface second rake angle larger than the corresponding first rake angle, so that the problem that the negative rake angle or the rake angle of the cutting edge of the spiral groove forming milling cutter is too small is effectively solved, the sharpness of the spiral groove forming milling cutter is obviously improved, the cutting resistance is reduced, the thermal damage to the surface of a workpiece is reduced, the cutting efficiency and the cutting precision are greatly improved, the machining precision is improved, the machining precision can be kept even when the cutter is used for a long time, and the service life of the milling cutter is also greatly improved. The application limits the formed milling cutter body part to be made of integral hard alloy materials, and various treatment modes in the prior art do not lead the sharpness improving direction to be distributed along the cutting edge, so that the similar large rake angle of all the cutting edges cannot be obtained, and the cutter has poor machining precision, machining efficiency and machining service life. The milling cutter with the same material is not provided with auxiliary chip flutes distributed along the cutting edge in the prior art, so that the cutting resistance is high, a Ti alloy hardening layer is generated by Ti alloy, a tortoise crack is easily generated on a workpiece, the service life of the workpiece is influenced, the existence of a large negative angle is realized, the friction force between a cutter and the workpiece is increased, the cutter yielding phenomenon is generated besides the hardening layer, the machining precision is directly influenced, and the milling cutter is unacceptable in high-precision machining. The formed milling cutter can keep good sharpness, and does not have hardening layers, tortoise cracks and cutter-back phenomena.

The cemented carbide of the present application has a general meaning understood by those skilled in the art, and is a powder metallurgical product obtained by sintering a carbide (WC, tiC) of a refractory metal of high hardness in a vacuum furnace or a hydrogen reduction furnace as a main component, and cobalt (Co) or nickel (Ni), molybdenum (Mo) as a binder. Its resistance is much higher than that of high-speed steel, about 800-1000 deg.C, and the allowable cutting speed is about 4-10 times that of high-speed steel. The hardness is very high, can reach (89-91) HRA, and can reach 93HRA; but the bending strength is 1.1-1.5 GPa, which is only half of high-speed steel; impact toughness of 0.04MJ/m ² About, it is less than 1/25 to 1/10 of that of high-speed steel. The heat resistance and the wear resistance of the cutting tool are good, so that the cutting tool has increasingly application to cutting tools with less complex edge shapes. The cemented carbide of the present application comprises one selected from the group consisting of: such as tungsten-cobalt (WC-Co) cemented carbide, tungsten-titanium-cobalt (WC-Ti-Co) cemented carbide, tungsten-titanium-tantalum (niobium) cemented carbide (WC-TaC (NbC) -Co), tungsten-titanium-cobalt-tantalum (niobium) cemented carbide and the like, cemented carbide based on WC, tiC-based cemented carbide, fine-grain ultrafine-grained cemented carbide, steel cemented carbide, coated cemented carbide and the like.

In some embodiments, the negative angle face second rake angle is 3 to 65 degrees, such as 5 to 35 degrees, such as 3 to 35 degrees, greater than the first rake angle. The person skilled in the art can adjust the negative angle surface cutting edge according to the need, and generally, the smaller the first rake angle of any selected point of the negative angle surface cutting edge is, the larger the second rake angle of the negative angle surface formed by arranging the auxiliary chip flute is, so that the effect of sharp cutting edge is achieved.

In some embodiments, the angle of the helical groove is the angle of the direction of the helix with the main axis, the angle of the helical groove is between 3 and 55 degrees, such as 15 to 55 degrees, such as 25 to 50 degrees, such as 15 to 50 degrees, such as 25 to 45 degrees; the secondary chip flute also extends in a length direction along the direction of the side cutting edge, the secondary chip flute having a flute face proximate the side cutting edge such that the flute face of the secondary chip flute proximate the side cutting edge forms a side second rake angle that is greater than the corresponding first rake angle. In general, the greater the angle of the helical groove, the faster the first rake angle varies along the cutting edge, and the more pronounced the sharpness of the milling cutter varies at different locations of the cutting edge. In order to enable the milling cutter cutting edge to meet the sharpness requirement on the whole, the application further limits that the auxiliary chip flute also extends along the direction of the side surface cutting edge in the length direction, namely, the flute surface close to the negative angle surface cutting edge continues to extend along the direction of the side surface cutting edge to form the flute surface close to the side surface cutting edge, thereby forming a negative angle surface second rake angle which is larger than the corresponding first rake angle near the negative angle surface cutting edge and forming a side surface second rake angle which is larger than the corresponding first rake angle near the side surface cutting edge, and effectively solving the problems of the negative rake angle of the spiral flute forming milling cutter cutting edge and the too small rake angle of the cutting edge, such as changing the negative rake angle into a positive rake angle. Further improves the cutting efficiency and the cutting precision in a larger range and prolongs the service life of the cutter. The extending direction of the auxiliary chip flute is consistent with the cutting edge, and when the cutting edge is curved, the auxiliary chip flute extends in a curve. In the present application, the length direction of the sub chip pocket means a direction which coincides with the extending direction of the sub chip pocket, and thus the length direction of the sub chip pocket and the extending direction of the sub chip pocket have the same meaning and can be used interchangeably.

In some embodiments, the secondary flutes extend along the entire edge such that all actual rake angles are greater than or equal to 5 degrees to less than or equal to 45 degrees, greater than or equal to 10 degrees to less than or equal to 35 degrees, greater than or equal to 15 degrees to less than or equal to 25 degrees, or greater than or equal to 27 degrees to less than or equal to 40 degrees. In order to make the entire cutting edge of the formed milling cutter meet sharpness requirements, the secondary flutes may extend along the entire cutting edge such that the actual rake angle of any selected point of the entire cutting edge meets a specific range. For the cutting edge provided with the auxiliary chip flute, the actual rake angle is the second rake angle. The present application defines that the secondary chip flute extends along the entire cutting edge, but for the cutting edge of a helical flute formed milling cutter, there is a difference in the cutting edge rake angles at different cutting edges, for example, the first rake angle of the cutting edge increases gradually along the cutting edge from an excessively small negative angle to a positive angle, during which change a portion of the first rake angle of the cutting edge is within a desired actual rake angle range, and the secondary chip flute is not required to be provided in the vicinity of the portion of the cutting edge, at which point the actual rake angle is the first rake angle. The application thus defines that the secondary flutes extend along the entire edge, including the case where no secondary flutes are provided in a specific region of the cutting edge. The auxiliary chip flutes can be reasonably arranged according to the rake angles of different cutting edge regions by a person skilled in the art, and finally the actual rake angle of the whole cutting edge meets the range limited by the cutting tool, so that the sharpness is improved along the direction of the cutting edge distribution, the cutting efficiency is improved, the cutting resistance is reduced, and the service life of the cutting tool is prolonged while the machining precision is ensured.

In some embodiments, the secondary flutes have a width of 0.15mm to 3mm or 3% to 30% of the milling cutter diameter. For example, the width of the secondary chip flute is 0.3mm to 2.5mm, or 0.5mm to 2mm, or 0.8mm to 1.8mm, or 1mm to 1.5mm, or the width of the secondary chip flute is 3% to 30%, or 5% to 25%, or 8% to 18%, or 10% to 15% of the diameter of the milling cutter. The width of the auxiliary chip flute refers to the dimension of the auxiliary chip flute on the front cutter surface, which is perpendicular to the extending direction of the cutting edge, and the diameter of the milling cutter refers to the diameter of the maximum excircle of the cutting edge rotation when the milling cutter works.

In some embodiments, the secondary flutes have a depth of 0.1 to 2mm, or 0.3 to 1.5mm. For example, the depth of the secondary chip flute is 0.5 to 1.2mm, or 0.6 to 1mm.

In some embodiments, the flute surfaces of the secondary flutes adjacent the negative angle face cutting edge and/or adjacent the side face cutting edge extend in a wave-like manner along the direction of the cutting edge, or the secondary flutes have flute bottom surfaces that connect with the flute surfaces adjacent the negative angle face cutting edge and/or adjacent the side face cutting edge and are substantially parallel to the rake surface, the flute bottom surfaces being undulating. The wavy extension of groove face or the wavy fluctuation of groove bottom surface both can play the effect of strengthening rib, improve the blade intensity under the prerequisite of not reducing the sharpness of blade, improve the durability of blade, thereby improve the machining precision, make the cutter also can keep the machining precision under long-time use, reduce the thermal damage on work piece surface, can also further improve the linear velocity when milling, practice shows that under the circumstances that the groove face that is close to the blade that makes vice chip pocket forms the wave, the cutter can process with higher linear velocity, the stable performance of cutter, the precision of work piece also can be guaranteed, thereby machining efficiency has been improved.

In some embodiments, the milling cutter has a diameter of 5mm to 80mm, such as 5mm to 50mm, such as 8mm to 40mm,10mm to 30mm.

In some embodiments, the secondary flutes are prepared using a processing method that does not create thermal damage.

In some embodiments, the secondary flutes are prepared using a femtosecond pulse laser machining method. When the femtosecond pulse laser is processed, the total amount of heat provided each time is small and concentrated, the heat generated by processing is not transferred to the inside of the workpiece, and the cutting scraps are gasified, so that a large amount of heat is taken away, namely, the speed of the cutting scraps gasification taking away the heat is higher than the speed of the heat transferred in the inside of the workpiece, so that the surface of the workpiece is not damaged by heat. And other laser processing methods in the prior art are adopted, the heat provided at one time is large, and the surface of the workpiece is easily damaged by heat.

The preparation methods of the helical groove forming milling cutter of the prior art are known to the person skilled in the art and comprise the following steps: 1. calculating the shape of the spiral groove forming milling cutter according to actual needs, and selecting a proper hard alloy bar stock, 2, starting from the hard alloy bar stock, forming a blank of the spiral groove forming milling cutter by grinding the hard alloy bar stock, 3, forming a semi-finished product of the spiral groove forming milling cutter by finish machining and grinding, and 4, performing PVD coating treatment on the semi-finished product, thereby forming a finished product of the spiral groove forming milling cutter.

The method for increasing the sharpness of the spiral groove forming milling cutter is mainly characterized in that auxiliary chip flutes are processed on the basis of the semi-finished product, and PVD coating treatment is carried out on the semi-finished product with the auxiliary chip flutes. In addition, the present application also provides a method of treating a helical flute forming mill, which is junk or non-junk, comprising optionally grinding a rake face of the helical flute forming mill, providing the helical flute forming mill with secondary flutes, and then PVD coating the helical flute forming mill provided with secondary flutes.

Accordingly, the present application also discloses a method of increasing the sharpness of a helical flute forming mill, wherein the helical flute forming mill comprises a forming mill body portion and optionally a connecting portion for direct or indirect connection with a machine tool, at least the forming mill body portion being of unitary cemented carbide material, the forming mill body portion having a plurality of cutting edges each independently having a rake face, a relief face and a cutting edge, and a plurality of main chip flutes corresponding to the cutting edges, the rake face forming a first rake angle at each of the cutting edges, the main chip flutes being helical flutes, each of the cutting edges comprising at least one cutting tooth, the relief faces of the cutting teeth being divided into negative, positive and side faces so as to correspond to three cutting edges, namely a negative angle face cutting edge, a positive angle face cutting edge and a side cutting edge, characterized in that the method comprises: and forming an auxiliary chip flute on the front cutter surface, wherein the auxiliary chip flute extends along the direction of the negative angle surface cutting edge in the length direction, and the auxiliary chip flute is provided with a flute surface close to the negative angle surface cutting edge, so that the flute surface of the auxiliary chip flute close to the negative angle surface cutting edge forms a negative angle surface second rake angle, and the negative angle surface second rake angle is larger than the corresponding first rake angle. According to the application, the auxiliary chip flute extending along the direction of the negative angle surface cutting edge is arranged to form the negative angle surface second rake angle which is larger than the corresponding first rake angle, so that the problem of the negative rake angle of the cutting edge of the spiral groove forming milling cutter is effectively solved, the sharpness of the spiral groove forming milling cutter is obviously improved, the cutting resistance is reduced, the thermal damage on the surface of a workpiece is reduced, the cutting efficiency and the cutting precision are greatly improved, the machining precision is improved, and the cutter can maintain the machining precision even in long-time use, so that the service life of the milling cutter is also greatly prolonged. Various processing modes in the prior art do not enable the direction of sharpness improvement to be distributed along the cutting edge, so that the fact that all the cutting edges obtain similar large rake angles cannot be achieved, and the cutter processing precision, the processing efficiency and the processing service life are poor.

In some embodiments, the angle of the helical groove is the angle of the direction of the helix with the main axis, the angle of the helical groove is between 3 and 55 degrees, such as 15 degrees to 50 degrees, such as 25 degrees to 45 degrees; the secondary chip flute also extends in a length direction along the direction of the side cutting edge, the secondary chip flute having a flute face proximate the side cutting edge such that the flute face of the secondary chip flute proximate the side cutting edge forms a side second rake angle that is greater than the corresponding first rake angle. In general, the greater the angle of the helical groove, the faster the first rake angle varies along the cutting edge, and the more pronounced the sharpness of the milling cutter varies at different locations of the cutting edge. In order to enable the milling cutter cutting edge to meet the sharpness requirement on the whole, the application further limits that the auxiliary chip flute also extends along the direction of the side cutting edge in the length direction, namely, the flute surface close to the negative angle surface cutting edge continues to extend along the direction of the side cutting edge to form the flute surface close to the side cutting edge, so that a negative angle surface second rake angle which is larger than the corresponding first rake angle is formed near the negative angle surface cutting edge, and a side second rake angle which is larger than the corresponding first rake angle is formed near the side cutting edge, thereby effectively solving the problem of the negative rake angle of the spiral flute forming milling cutter cutting edge and the problem of too small cutting edge rake angle. Further improves the cutting efficiency and the cutting precision in a larger range and prolongs the service life of the cutter.

In some embodiments, the flute surfaces of the secondary flutes adjacent the negative angle face cutting edge and/or adjacent the side face cutting edge extend in a wave-like manner along the direction of the cutting edge, or the secondary flutes have flute bottom surfaces that connect with the flute surfaces adjacent the negative angle face cutting edge and/or adjacent the side face cutting edge and are substantially parallel to the rake surface, the flute bottom surfaces being undulating. The wavy extension of groove face or the wavy fluctuation of groove bottom surface both can play the effect of strengthening rib, improves blade strength under the prerequisite of not reducing the sharpness of blade, improves the durability of blade to improve machining precision, make the cutter also can keep machining precision under long-time use, reduce the thermal damage on work piece surface. The linear speed during milling can be further increased, so that the processing efficiency is improved.

In some embodiments, the secondary flutes are prepared using a processing method that does not create thermal damage. Therefore, the auxiliary chip flute part does not have a thermal damage layer, and the strength of the cutter is not degraded due to thermal damage after the auxiliary chip flute is arranged.

In some embodiments, the secondary flutes are prepared using a femtosecond pulse laser machining method. The auxiliary chip flute can be manufactured by femtosecond pulse laser processing and forming, for example, a precise numerical control laser machine which is purchased from the company of German Ma Jisen precision machine tool trade company under the trade name of LASETERC 50Shape can be adopted. It is generally considered that laser forming deteriorates the properties of cemented carbide, for example, heat damage is caused by picosecond and nanosecond processing, a heat damage layer is formed at the secondary chip pocket portion, the surface finish is extremely poor, the finishing requirements cannot be satisfied, and the service life of the tool is drastically reduced. Without being limited by theory, it is believed that the reason for this thermally damaged layer is that the oxidation of the cemented carbide, the change in microstructure in the alloy, and the reduction in hardness and wear resistance, which is evident by comparison with the life of a tool without a thermally damaged layer, is often less than half the life of a tool without a thermally damaged layer, and some even degrades to one fifth of the normal life or even less. The femtosecond pulse laser processing is adopted, the speed is extremely high, the thermal damage is not caused, the surface finish can reach the finish of 0.1-0.2nm, even a mirror surface can be realized, the method is suitable for finish machining, the sharpness of the cutting edge of a cutter is obviously improved after the auxiliary chip flute is arranged, the cutting resistance is greatly reduced, the cutter abrasion is reduced, the service life of the cutter is prolonged by 2-5 times, and the high-precision, high-flexibility and high-efficiency processing is realized.

The above-described ranges may be used alone or in combination. The application will be more readily understood by the following examples.

Examples

Example 1

The present embodiment discloses a helical flute forming mill, as shown in fig. 1 to 8, comprising a forming mill body portion 20 and a connecting portion 30 for direct connection with a machine tool, the forming mill body portion being of unitary cemented carbide material, the forming mill body portion having four cutting edges 100 and four main chip flutes 200 corresponding to the cutting edges, the cutting edges 100 each independently having a rake face 110, a relief face 120 and a cutting edge 130, the rake face being formed by a radius passing perpendicularly through the axis of the forming mill, the rake face forming a first rake angle at each of the cutting edges, the main chip flutes 200 being helical flutes, each of the cutting edges comprises three cutting teeth 300, as shown in fig. 3, the relief surface 120 of which is divided into a negative angle surface 121, a positive angle surface 122 and a side surface 123 so as to correspond to three cutting edges, namely, a negative angle surface cutting edge 131, a positive angle surface cutting edge 132 and a side surface cutting edge 133, characterized in that a sub chip flute 10 is provided on the rake surface, which extends in a length direction in the direction of the negative angle surface cutting edge 131, and which has a flute surface adjacent to the negative angle surface cutting edge so that the flute surface of the sub chip flute adjacent to the negative angle surface cutting edge forms a negative angle surface second rake angle, which is larger than the corresponding first rake angle.

The angle of the spiral groove is 25 degrees, and the angle of the spiral groove is the included angle between the direction of the spiral and the main shaft. Fig. 3 shows the angle ω of the spiral groove.

The secondary chip flute 10 also extends in the longitudinal direction in the direction of the side edge 133, the secondary chip flute having a flute face adjacent the side edge, fig. 5 showing the secondary chip flute disposed along a selected point of the side edge 133 (i.e., the side edge on the A-A section in fig. 4), fig. 6 being an enlarged partial view of the portion shown in dashed line in fig. 5, showing the flute face 11 adjacent the side edge, such that the flute face of the secondary chip flute adjacent the side edge forms a side second rake angle, the side second rake angle being greater than the corresponding first rake angle.

Fig. 7 is an enlarged view of a portion of the cross-sectional view of the inner edge of the dashed-line frame in fig. 4, in which the auxiliary chip flute 10 extends in a curved line on the paraxial surface and the lateral corresponding edges of the three chip teeth 300, wherein the paraxial surface corresponding edges are negative angle surface edges 131 and the lateral corresponding edges are lateral edges 133, and the lateral edges include convex arc-shaped edges at the peaks and concave arc-shaped edges at the valleys in fig. 7.

FIG. 8 is a B-B cross-sectional view of the cutting tooth in the middle of FIG. 7, with the B-B cross-sectional plane of FIG. 7 perpendicular to the cross-sectional edge at the near axial plane. In fig. 8, a first rake angle 1 and a second rake angle 2 at the cutting edge 130 are exemplarily marked in the case where the secondary chip flute 10 is provided. Wherein the first rake angle 1 is a negative angle, which is equal to 90 degrees minus the angle between the B-B cross-sectional plane (i.e., the plane perpendicular to the cutting edge of the cross-sectional point) and the intersection of the rake face and the flank face at the cutting edge (a 1 labeled in the figure), i.e., the value obtained by 90-a1 is-15 degrees. The second rake angle 2 is 25 degrees, and the value is equal to 90 degrees minus the included angle (a 2 marked in the figure) between the intersecting line of the B-B cross-sectional plane (namely, the plane perpendicular to the cutting edge of the cross-sectional point) and the groove surface of the auxiliary chip flute, which is close to the cutting edge, and the rear tool surface at the cutting edge, namely, the value obtained by 90-a2 is 25 degrees. The dashed line forming the common edge of a1 and a2 in fig. 8 is the intersection of the B-B cross-sectional plane with the clearance-free flank surface. For the selected point edge 130 of the cutting edge in fig. 8, 25 degrees is the negative face second rake angle, -15 degrees is the corresponding first rake angle, where the actual rake angle is 25 degrees.

Through setting up the vice chip flute that extends along blade direction, form the negative angle face second rake angle and the side second rake angle that are greater than corresponding first rake angle, effectively solve the problem that spiral flute shaping milling cutter cutting edge negative rake angle or rake angle are too little, improve cutting efficiency and cutting precision to improve the machining precision, make the cutter also can keep the machining precision under long-time use.

The diameter of the milling cutter is 20mm, the width of the auxiliary chip flute is 2mm, and the depth of the auxiliary chip flute is 0.3mm. The helical groove forming milling cutter of the embodiment of the application is prepared by obtaining helical groove forming milling cutter blanks from the market, forming a semi-finished product of the helical groove forming milling cutter by finish machining and grinding, then arranging auxiliary chip flutes on the helical groove forming milling cutter, and finally performing PVD coating treatment on the semi-finished product, thereby forming a finished product of the helical groove forming milling cutter. Wherein the step of finish grinding the semi-finished product of the helical groove forming milling cutter is accomplished by a grinding machine. The PVD coating process is prepared using prior art methods. The auxiliary chip flute is manufactured by femtosecond pulse laser processing and forming, for example, a precise numerical control laser machine which is purchased from the company of German Ma Jisen precision machine tool trade company under the trade name of LASETERC 50Shape can be adopted.

Example 2

This example discloses a helical flute forming mill which is substantially identical to the forming mill of example 1, except that: in this embodiment, the auxiliary chip flute is disposed only at the negative angle surface cutting edge, which is located on the paraxial surface of the tool.

Example 3

This example discloses a helical flute forming mill which is substantially identical to the forming mill of example 1, except that: in this embodiment, the auxiliary chip flute is disposed only at the negative angle surface cutting edge, which is located on the paraxial surface of the tool. In this embodiment, the groove surface of the auxiliary chip flute, which is close to the negative angle surface cutting edge, is wavy and extends along the direction of the cutting edge, and the auxiliary chip flute is provided with a groove bottom surface 12, wherein the groove bottom surface is connected with the groove surface, which is close to the negative angle surface cutting edge, and is basically parallel to the rake surface, and the groove bottom surface is wavy and undulates. Fig. 9 shows a groove surface 11 extending in a wavy shape in the cutting edge direction at the negative angle surface cutting edge, and a groove bottom surface 12 undulating in a wavy shape.

Example 4

This example discloses a helical flute forming mill which is substantially identical to the forming mill of example 1, except that: in this embodiment, the groove surface of the auxiliary chip flute, which is close to the negative angle surface cutting edge, and the groove surface of the auxiliary chip flute, which is close to the side surface cutting edge, are wavy and extend along the cutting edge direction, or the auxiliary chip flute has a groove bottom surface, and the groove bottom surface is connected with the groove surface, which is close to the negative angle surface cutting edge, and the groove surface, which is close to the side surface cutting edge, and is substantially parallel to the rake surface, and the groove bottom surface is wavy and undulates.

Example 5

As shown in fig. 10, this embodiment discloses a helical flute forming mill which is substantially identical to the forming mill of embodiment 1, except that: the angle of the helical flute in this embodiment is 20 degrees and the secondary flute extends along the entire cutting edge such that all practical rake angles are 25 degrees.

Example 6

This example discloses a helical flute forming mill which is substantially identical to the forming mill of example 1, except that: the angle of the helical flute in this embodiment is 25 degrees and the secondary flute extends along the entire cutting edge such that all practical rake angles are 27 degrees.

An aircraft disk machining test was performed using a similar tool without auxiliary flutes as a control and a tool according to examples 1 to 6 of the present application, the material being a titanium alloy, and the milling machine being a milling cutter of the company hamer, C42, with the following results:

TABLE 1

The applicant has unexpectedly found that the formed milling cutter of the present application is capable of machining more work pieces than a formed milling cutter without the auxiliary chip flutes, whereas a milling cutter of the same material, since the auxiliary chip flutes are not provided, the Ti alloy generates a Ti alloy hardened layer when machining the 2 nd work piece, thereby causing a tortoise crack, which affects the life of the engine blade disk, and since there is a large negative angle, the friction between the cutter and the work piece increases, and a cutter-back phenomenon is generated in addition to the hardened layer, which directly affects the machining accuracy, which is unacceptable in high-accuracy machining. The formed milling cutter can keep good sharpness even after 3-5 workpieces are produced, and hardening layers, tortoise cracks and cutter-back phenomena are avoided. Under the condition that the groove surface of the auxiliary chip groove, which is close to the cutting edge, is formed into a wave shape, the cutter can process at a higher linear speed of 90 m/s, the performance of the cutter is stable, the precision of a workpiece can be ensured, and the processing efficiency is improved.

The foregoing is merely exemplary embodiments of the present disclosure and is not intended to limit the scope of the disclosure, which is defined by the appended claims.

Claims

1. A helical flute forming mill comprising a forming mill body portion and optionally a connecting portion for direct or indirect connection to a machine tool, at least the forming mill body portion being of unitary cemented carbide material, the forming mill body portion having a plurality of cutting edges and a plurality of major chip flutes corresponding to the cutting edges, the cutting edges each independently having a rake face, a relief face and a cutting edge, wherein the rake face is formed by a radius passing perpendicularly through the forming mill axis, the rake face forming a first rake angle at each of the cutting edges, the major chip flutes being helical flutes, each of the cutting edges comprising at least one cutting tooth, the relief faces of the cutting teeth being divided into negative angle faces, positive angle faces and side faces so as to correspond to three cutting edges, namely a negative angle face cutting edge, a positive angle face cutting edge and a side cutting edge,

the cutting tool is characterized in that an auxiliary chip flute is arranged on the front tool face, the auxiliary chip flute extends in the direction of the negative angle face cutting edge in the length direction, and the auxiliary chip flute is provided with a flute face close to the negative angle face cutting edge, so that the flute face, close to the negative angle face cutting edge, of the auxiliary chip flute forms a negative angle face second rake angle, and the negative angle face second rake angle is larger than the corresponding first rake angle.

2. The helical flute forming milling cutter of claim 1, wherein the negative face second rake angle is 3 to 65 degrees greater than the first rake angle.

3. The helical flute forming milling cutter according to claim 1, wherein the angle of the helical flute is the angle of the direction of the helix with the main shaft, the angle of the helical flute being between 3 and 55 degrees; the secondary chip flute also extends in a length direction along the direction of the side cutting edge, the secondary chip flute having a flute face proximate the side cutting edge such that the flute face of the secondary chip flute proximate the side cutting edge forms a side second rake angle that is greater than the corresponding first rake angle.

4. The helical flute forming milling cutter according to claim 2, wherein the secondary flutes extend along the entire cutting edge such that all actual rake angles are greater than or equal to 5 degrees and less than or equal to 45 degrees.

5. The helical flute forming milling cutter of claim 1, wherein the secondary flutes have a width of 0.15mm to 3mm or 3% to 30% of the milling cutter diameter.

6. The helical flute forming milling cutter of claim 1, wherein the secondary flutes have a depth of 0.1 to 2mm.

7. The helical flute forming milling cutter according to claim 1, wherein the flute surfaces of the secondary flutes adjacent the negative angle face cutting edge and/or the flute surfaces adjacent the side face cutting edge extend in a wave-like manner along the direction of the cutting edge, or wherein the secondary flutes have flute bottom surfaces that connect with the flute surfaces adjacent the negative angle face cutting edge and/or the flute surfaces adjacent the side face cutting edge and are parallel to the rake surface, the flute bottom surfaces undulating in a wave-like manner.

8. The helical flute forming milling cutter of claim 1, wherein the milling cutter has a diameter of 5mm to 80mm.

9. The helical flute forming milling cutter according to claim 1, wherein the secondary chip flute is prepared using a machining method that does not cause thermal damage.

10. The helical flute forming milling cutter of claim 1, wherein the secondary chip flutes are produced using a femtosecond pulse laser machining process.

11. The helical flute forming milling cutter of claim 1, wherein the negative face second rake angle is 5 to 35 degrees greater than the first rake angle.

12. A helical flute forming milling cutter according to claim 3, wherein the helical flute angle is 15 degrees to 50 degrees.

13. A helical flute forming milling cutter according to claim 3, wherein the helical flute angle is 25 degrees to 45 degrees.

14. The helical flute forming milling cutter according to claim 2, wherein the secondary flutes extend along the entire cutting edge such that all actual rake angles are greater than or equal to 10 degrees and less than or equal to 35 degrees.

15. The helical flute forming milling cutter according to claim 2, wherein the secondary flutes extend along the entire cutting edge such that all actual rake angles are 15 degrees or greater to 25 degrees or less.

16. The helical flute forming milling cutter according to claim 2, wherein the secondary flutes extend along the entire cutting edge such that all actual rake angles are greater than or equal to 27 degrees to less than or equal to 40 degrees.

17. The helical flute forming milling cutter of claim 1, wherein the secondary flutes have a depth of 0.3 to 1.5mm.

18. The helical flute forming milling cutter of claim 1, wherein the milling cutter has a diameter of 8mm to 40mm.

19. The helical flute forming milling cutter of claim 1, wherein the milling cutter has a diameter of 10mm to 30mm.