Staggered-tooth vibration reduction ball-end micro-milling cutter and preparation method thereof

Abstract

The application discloses a staggered-tooth ball head micro-milling cutter and a preparation method thereof. The ball head micro-milling cutter is mainly composed of a tool shank, a tool rod and a tool head. The tool head is spherical. The tool head is provided with a plurality of central-symmetrical main cutting edges. Each main cutting edge is divided into a staggered-tooth structure by a plurality of spiral-direction-opposite chip-breaking grooves. The tool edges are staggered and overlapped. There is no discontinuous empty cutting area. The surface quality is improved. The contact area between the tool edge and the workpiece surface is reduced. Chip breaking is promoted. The cutting force and heat are reduced. The cutting amount of each cutting edge is different. The vibration deformation problem in the micro-groove machining process of a thin-walled part is overcome. In the preparation, the tool head part is grooved and precisely sharpened to machine the spiral grooves and the main cutting edges. Then, the main cutting edges are grooved to machine the spiral-direction-opposite chip-breaking grooves, so that the ball head micro-milling cutter with the staggered-tooth structure is formed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of cutting tool preparation, and more particularly to a staggered-tooth vibration-reducing ball-end micro-milling cutter and a preparation method thereof. BACKGROUND

[0002] Thin-walled structural parts are widely used in the fields of medical devices, aerospace, electronics, 3C, etc. However, the overall size to cross-sectional size ratio of micro-thin-walled parts is relatively large, and the relative rigidity is poor. In the process of cutting thin-walled parts, the relative rigidity gradually decreases as the thickness of the thin-walled part is continuously reduced, and cutting vibration is easily generated, which leads to deformation of the workpiece structure and deterioration of the machining surface quality. In particular, when using a ball-end micro-milling cutter to mill micro-structures such as concave curved cavities and deep grooves on the surface of a thin-walled part, the material removal amount is relatively large, and the rigidity of the workpiece is weakened, so that the influence of cutting vibration caused by milling force on the deformation of the workpiece and the machining quality is more serious. In addition, the conventional ball-end micro-milling cutter is mostly single-edge or double-edge structure, and the material removal amount of each cutting edge is the same in the cutting process, which makes the vibration frequency of each cutting edge the same, thereby more easily causing self-excited vibration and regenerative chatter of the cutter and the workpiece, making the deformation of the workpiece machining surface uneven, and increasing the instantaneous maximum stress of the tool tip, so that the tool is more prone to chipping, and it is difficult to meet the high-quality machining requirements. SUMMARY

[0003] The purpose of the present application is to provide a staggered-tooth vibration-reducing ball-end micro-milling cutter and a preparation method thereof, which significantly reduces the vibration and deformation of thin-walled structural parts, improves the machining surface quality of thin-walled structural parts, prolongs the tool life, and realizes high-quality machining of thin-walled structural parts.

[0004] The purpose of the present application is achieved by the following technical solutions:

[0005] A staggered-tooth vibration-reducing ball-end micro-milling cutter, comprising a cutter head and a plurality of main cutting edges arranged on the cutter head, a plurality of chip division grooves divide each main cutting edge into a plurality of blade micro-teeth, and the plurality of blade micro-teeth form a staggered-tooth structure;

[0006] The basic profile of the cutter head is spherical, and the axial section of the cutter head is an arc of advantage;

[0007] The main cutting edges are divided by a plurality of spiral grooves arranged symmetrically about the center of the cutter head axis;

[0008] The center line of the plurality of spiral grooves is a spherical spiral line, and the axis of the plurality of spiral grooves is the axis of the cutter head;

[0009] The center line of the plurality of chip division grooves is a spherical spiral line, and the axis of the plurality of chip division grooves is the axis of the cutter head;

[0010] The center line of one of the chip division grooves and the center line of the corresponding chip division groove on the adjacent main cutting edge are on the same spherical spiral line;

[0011] The main cutting edges and the chip dividing grooves are opposite in rotation direction; the chip dividing grooves and the blade microteeth on each main cutting edge are not on the same horizontal line;

[0012] The main cutting edges and the spiral grooves are the same in rotation direction.

[0013] The radius of the optimal arc accounts for 55%-85% of the axial length.

[0014] The number of main cutting edges is 3-6; the spiral angle of the multiple spiral grooves is 20°-40°.

[0015] The spiral angle of the multiple chip dividing grooves is 30°-50°.

[0016] The minimum axial distance between the blade microteeth on the adjacent two main cutting edges does not exceed 50% of the length of the long side of the corresponding blade microteeth.

[0017] The main cutting edges and the spiral grooves are right-handed, and the chip dividing grooves are left-handed.

[0018] The main cutting edges and the spiral grooves are left-handed, and the chip dividing grooves are right-handed.

[0019] Further comprising a shank, a shank connected to the shank, and a neck provided on the shank, and the tool head is provided on the neck.

[0020] A preparation method of the staggered-tooth vibration-reducing ball head micro-milling cutter, which comprises the following steps:

[0021] Step 1: grinding the cutter blank bar to form the shank and the shank of the milling cutter;

[0022] Step 2: slot grinding the cutter blank bar to process multiple spiral grooves and main cutting edges, and the rotation direction of the processed main cutting edges and the spiral grooves is the same;

[0023] Step 3: grinding the cutter blank bar to obtain a spherical tool head and a neck;

[0024] Step 4: precisely sharpening the main cutting edges;

[0025] Step 5: adjusting the angle of the grinding wheel to slot grind multiple chip dividing grooves on each main cutting edge, the rotation direction of the processed main cutting edges and the chip dividing grooves is opposite, and the processing of the tool head is completed.

[0026] The present application has the following beneficial effects:

[0027] 1) The blade microteeth of the staggered-tooth cutter are staggered and overlapped, there is no discontinuous empty cutting area, the phenomenon of “leakage cutting” is avoided, and the surface processing quality is improved;

[0028] 2) The cutting amount of each cutting edge of the staggered tooth tool is different, which overcomes the problem of chattering deformation and tool chipping caused by each cutting edge using a single cutting amount during the machining of micro-grooves of thin-walled parts.

[0029] 3) Staggered tooth cutting tools can significantly reduce the contact area between the cutting edge and the workpiece surface during the cutting process, promote chip removal and chip breaking, reduce cutting force and cutting heat, and extend tool life. Attached Figure Description

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and specific implementation methods.

[0031] Figure 1 This is a schematic diagram of the overall structure of the staggered-tooth vibration-damping ball end mill of the present invention;

[0032] Figure 2 This is a schematic diagram of the cutter head structure of the present invention;

[0033] Figure 3 This is a schematic diagram of the staggered tooth structure of the present invention;

[0034] Figure 4 This is a schematic diagram of the grinding process of the head and neck of the staggered-tooth vibration-damping ball end mill of the present invention.

[0035] In the diagram: 1. Tool holder; 2. Tool neck; 3. Tool shank; 4. Tool head; 41. Main cutting edge; 42. Chip flute; 43. Staggered tooth structure; 44. Spiral flute; 45. Micro-tooth cutting edge; 5. Forming wheel; 6. Diamond wheel. Detailed Implementation

[0036] The present invention will now be described in further detail with reference to the accompanying drawings.

[0037] like Figure 1 As shown, a staggered-tooth vibration-damping ball end mill includes a shank 1, a neck 2, and a shank 3. A cutter head 4 is fixedly connected to the shank 3. The ball end mill 4 is provided with several right-handed main cutting edges 41, and the right-handed main cutting edges 41 are divided by several left-handed chip grooves 42 to form multiple cutting edge micro teeth 45. Each cutting edge micro tooth 45 forms a staggered tooth structure 43.

[0038] Preferably, the overall length of the milling cutter is 40mm-50mm, and the outer diameter of the shank 1 is 2mm-4mm. Here, the overall length of the milling cutter is 50mm, the outer diameter of the shank 1 is 4mm, and the cutter head 4 is provided with 6 right-hand spiral grooves 44 and 6 right-hand main cutting edges 41. Each right-hand main cutting edge 41 is divided by 3 left-hand chip-breaking grooves 42 to form a staggered tooth structure 43.

[0039] like Figure 2As shown, the basic outline of the cutter head is spherical, where R is the radius of the circumcircle of the axial section of the spherical cutter head, and l is the axial length of the axial section. The outer diameter R is 0.5mm-1.0mm. The cutter head 4 is provided with several right-handed helical grooves 44 symmetrically arranged about the center of the tool axis and several right-handed main cutting edges 41. Each right-handed main cutting edge 41 is divided by several left-handed chip-breaking grooves 42 to form cutting edge micro-teeth. All cutting edge micro-teeth together form a staggered tooth structure 43.

[0040] Preferably, the radius R is 0.5 mm, the axial length l is 0.9 mm, and the ratio of R to l is 55.6%.

[0041] like Figure 3 As shown, α is the angle between the axis of the right-hand helical groove and the axis of the tool, which is the right-hand helical angle; β is the angle between the axis of the left-hand chip-breaking groove and the axis of the tool, which is the left-hand helical angle; h is the minimum axial distance between the cutting edge micro-teeth 45 on two adjacent right-hand main cutting edges 41; the shape of the cutting edge micro-teeth 45 is approximately a parallelogram, m is the length of the short side of the cutting edge micro-teeth 45, and n is the length of the long side of the cutting edge micro-teeth 45.

[0042] Preferably, the right-hand helix angle α is 30°, the left-hand helix angle β is 40°, and the shape of the blade micro-tooth 45 in the staggered tooth structure 43 can be approximated as a parallelogram. Then, the short side length m of the blade micro-tooth 45 is 0.035mm, and the long side length n of the blade micro-tooth 45 is 0.10mm.

[0043] The centerline of each right-hand spiral groove 44 is a right-hand spherical spiral, and its axis is the tool axis. The centerline of each left-hand chip-breaking groove 42 is a left-hand spherical spiral, and its axis is the tool axis. The center of the right-hand and left-hand spherical spirals is the same as the center of the tool head 4. The axis of the right-hand spiral groove and the axis of the left-hand chip-breaking groove are in the same plane as the tool axis.

[0044] The left-hand chip-breaking grooves 42 on the surface of the cutter head 4 divide each right-hand main cutting edge 41 into a staggered tooth structure 43. This structure can significantly reduce the contact area between the cutting edge and the workpiece surface during the cutting process, enhance the chip removal and chip breaking ability of the tool, reduce cutting force and cutting heat, and reduce tool wear and vibration generated during the machining process.

[0045] The minimum axial distance h between the micro-teeth 45 on two adjacent right-hand main cutting edges does not exceed 50% of the length n of the long side of the corresponding micro-teeth 45, ensuring that the cutting area of ​​each edge of the milling cutter completely covers the tool rotation area, thus avoiding the phenomenon of "missed cutting".

[0046] And each of the right-hand main cutting edge 41 is provided with a plurality of left-hand chip breaker groove 42, wherein the middle line of one left-hand chip breaker groove 42 and the middle line of the corresponding left-hand chip breaker groove 42 on the adjacent right-hand main cutting edge 41 are on the same left-hand spherical spiral line. This structure design makes the staggered overlapping arrangement of the blade micro teeth 45 without discontinuous empty cutting area, avoiding the "leakage cutting" phenomenon, and improving the processing quality of the groove inner surface;

[0047] Because the left-hand chip breaker groove 42 and the blade micro teeth 45 on each right-hand main cutting edge 41 are not on the same horizontal line, the cutting amount of each cutting edge of the tool is different, which overcomes the problem of vibration deformation and tool blade collapse in the process of machining the micro groove of the thin-walled part due to the single cutting amount of each blade;

[0048] The preparation method of the staggered tooth vibration reduction ball head micro milling cutter will be described in detail below.

[0049] The preparation method of the staggered tooth vibration reduction ball head micro milling cutter comprises the following steps:

[0050] Step one: using a precision tool grinder to grind the tool blank bar through a forming grinding wheel 5 to form the handle 1 and the rod 3 part of the milling cutter.

[0051] Step two: using a precision tool grinder to groove grind the tool blank bar through a forming grinding wheel 5 to process several right-hand spiral grooves 44 and several right-hand main cutting edges 41. The middle line of each right-hand spiral groove 44 is a right-hand spherical spiral line, the spherical center of which is the same as that of the tool head 4, and the included angle α between the axis and the tool axis is 30°.

[0052] In step two, the forming grinding wheel 5 moves according to the equation in the spherical coordinate system: ρ=0.5, θ=t*180, ψ=t*360*10, where ρ is the distance from the origin to the point, θ is the included angle between the point and the origin and the X axis, ψ is the included angle between the projection of the point and the origin on the X-Y plane and the X axis, and t is the parameter; the grinding speed is 30-40 m / s, the feed speed is 0.6-0.8 mm / s, the grinding speed is selected as 40 m / s, the feed speed is selected as 0.6 mm / s, and the grinding depth is 550 μm;

[0053] Step three: using a precision tool grinder to grind the tool blank bar through a forming grinding wheel 5 to obtain the basic contour of the tool head 4 and the neck 2 of the milling cutter.

[0054] Step four: using the precision tool grinder by forming grinding wheel 5 to right-hand main cutting edge precision sharpening processing, forming grinding wheel according to the same spherical coordinate equation movement, grinding speed is 20-30m / s, feed speed is 0.25-0.4mm / s, here select grinding speed is 30m / s, feed speed is 0.25mm / s, grinding depth is 10μm;

[0055] Step five: adjust the angle of grinding wheel, using diamond grinding wheel 6, right-hand main cutting edge 41 is grooving grinding processing, diamond grinding wheel 6 according to the same spherical coordinate equation movement, grinding speed is 20m-30 / s, feed speed is 0.4-0.6mm / s, here select grinding speed is 30m / s, feed speed is 0.4mm / s, grinding depth is 30μm, so as to process several left-hand chip dividers 42 on each right-hand main cutting edge, complete the machining of the part of the tool head 4.

[0056] The above only for the preferred embodiments of the present application, can not be limited once the range of the present application is implemented, any non-essential changes using this idea to the present application, still belongs to the protection scope of the present application.

Claims

1. A method of manufacturing a staggered ball end micro end mill, characterized in that: The toothed damping ball head micro-milling cutter comprises a cutter head (4) and a plurality of main cutting edges (41) arranged on the cutter head (4), a plurality of chip division grooves (42) are arranged on each main cutting edge (41) to divide the main cutting edge (41) into a plurality of cutter edge micro-teeth (45), and the plurality of cutter edge micro-teeth (45) form a toothed structure (43). The basic profile of the cutter head (4) is spherical, and the axial section of the cutter head (4) is an optimal arc. The main cutting edge (41) is divided by a plurality of spiral grooves (44) which are symmetrically arranged about the center axis of the cutter head (4). The center line of the plurality of spiral grooves (44) is a spherical spiral line, and the axis of the plurality of spiral grooves (44) is the axis of the cutter head (4). The center line of the plurality of chip division grooves (42) is a spherical spiral line, and the axis of the plurality of chip division grooves (42) is the axis of the cutter head (4). The center line of one of the chip division grooves (42) and the center line of the corresponding chip division groove (42) on the adjacent main cutting edge (41) are on the same spherical spiral line. The rotation directions of the main cutting edge (41) and the chip division groove (42) are opposite, and the chip division groove (42) and the cutter edge micro-tooth (45) on each main cutting edge (41) are not on the same horizontal line. The rotation directions of the main cutting edge (41) and the spiral groove (44) are the same. The spiral angle of the plurality of chip division grooves (42) is 30-50°. The minimum axial distance between the cutter edge micro-teeth (45) on the adjacent two main cutting edges (41) is not more than 50% of the length of the corresponding cutter edge micro-tooth (45). The preparation method comprises the following steps: Step 1: grinding the cutter blank bar to form the shank (1) and the rod (3) of the milling cutter; Step 2: slot grinding the cutter blank bar to form a plurality of spiral grooves (44) and main cutting edges (41), and the rotation directions of the main cutting edges (41) and the spiral grooves (44) are the same; Step 3: grinding the cutter blank bar to obtain the spherical cutter head (4) and the neck (2); Step 4: precisely sharpening the main cutting edge (41); Step 5: adjusting the angle of the grinding wheel, slot grinding a plurality of chip division grooves (42) on each main cutting edge (41), and the rotation directions of the main cutting edge (41) and the chip division groove (42) are opposite, thereby completing the processing of the cutter head (4).

2. The method of making a staggered tooth vibration-damping ball-end micro end mill according to claim 1, wherein: The radius of the optimal arc accounts for 55-85% of the axial length.

3. The method of making a staggered tooth vibration-damping ball-end micro end mill according to claim 1, wherein: The number of main cutting edges (41) is 3-6, and the spiral angle of the plurality of spiral grooves (44) is 20-40°.

4. The method of making a staggered tooth vibration-damping ball-end micro end mill according to claim 1, wherein: The main cutting edge (41) and the spiral groove (44) are right-handed, and the chip division groove (42) is left-handed.

5. The method of making a staggered tooth vibration-damping ball-end micro end mill according to claim 1, wherein: The main cutting edge (41) and the spiral groove (44) are left-handed, and the chip division groove (42) is right-handed.

6. The method of making a staggered tooth vibration-damping ball-end micro end mill according to claim 1, wherein: The shank (1), the rod (3) connected to the shank (1), the neck (2) arranged on the rod (3), and the cutter head (4) arranged on the neck (2) are further included.

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