Ball head mold milling cutter

Abstract

The utility model relates to a ball head die milling cutter, which is applied to the field of die processing, and comprises a cutter handle and a cutting part arranged at one end of the cutter handle, the cutting part comprises a circumferential edge and a ball head edge part, the ball head edge part is provided with a ball head S-shaped cutting edge and two ball head rake faces, and the ball head cutting edge is provided with a variable backlash rake angle. The machining tool has the technical effects that the blade part of the ball head is the S-shaped blade, the S-shaped blade line adopts a smooth curve, the cutting uniformity of the blade part of the ball head and a machined surface is ensured, the machining vibration and stress concentration are reduced, the durability of the tool is high, and a complex curved surface can be machined. And by adopting the variable front angle of the backlash, the distribution of cutting resistance can be effectively improved, and the cut-in and cut-out processes are relatively stable. Cuttings can be smoothly discharged, and the cuttings are effectively prevented from being adhered to the cutting edge. Due to the false edge strip on the rear cutter surface, the extrusion and sleeking effects on the machined surface are increased, and meanwhile, the anti-tipping effect is also improved.

Description

Technical Field

[0001] The present application relates to the technical field of mold processing, and in particular to a ball-end mold milling cutter. Background Art

[0002] High-precision and high-efficiency processing methods are the development and trend of cutting processing. Improving tool processing efficiency usually adopts methods such as increasing cutting depth, increasing cutting tool rotation speed and increasing the number of cutting edges of the tool. Ball end mills are widely used in tool processing.

[0003] The mold has the characteristics of large structure size, complex working surface, frequent curvature changes, high requirements for surface quality and processing accuracy, etc. Ball-end milling cutters have outstanding advantages in mold cavity and complex curved surface forming processing. Ball-end end mills can be divided into straight-edge and spiral-edge according to the different shapes of their blade curves. The characteristic of the straight-edge is that the cutting edge of the ball head part is a straight line when viewed along the axial direction of the tool. The straight-edge milling cutter has poor chip removal during the cutting process, is prone to forming built-up edge, affects surface finish and accuracy, and wears quickly. At present, ball-end end mills with straight-edge blades are rarely used.

[0004] However, in the prior art, increasing the cutting depth and increasing the feed rate can easily lead to large cutting resistance and tool vibration, which can easily cause the tool to break. Increasing the number of tool teeth can easily lead to poor chip removal. The tooth clearance angle of conventional ball-end milling cutters is often constant, which is convenient for manufacturing and testing. However, since the cutting edge of each part of the ball head has different rotation radii from the center of the ball head to the peripheral edge, the linear speed is also different. Using the same tooth clearance angle will cause different cutting point resistance. Such tools are prone to cutting edge breakage under high impact conditions, resulting in reduced surface quality and machining accuracy, which affects tool performance and reduces tool life, affecting machining efficiency. Summary of the invention

[0005] In order to help solve the problem that existing ball-end mold milling cutters using the same tooth clearance rake angle are prone to cutting edge chipping, thereby resulting in tool performance and reduced life, affecting processing efficiency, the present application provides a ball-end mold milling cutter, which adopts the following technical solution: it includes a shank and a cutting portion arranged at one end of the shank, the cutting portion includes a peripheral edge and a ball-end cutting portion, the ball-end cutting portion is provided with a ball-end S-shaped cutting edge and two ball-end front cutting surfaces, and the ball-end front cutting surface is provided with a variable tooth clearance rake angle.

[0006] In a specific implementation manner, the variable tooth clearance rake angle is set to -3°, -2° and -3°.

[0007] In a specific possible implementation scheme, two chip removal grooves are provided along the outer peripheral wall of the cutting portion, and the two chip removal grooves spirally extend from the tool handle to the ball head cutting edge, and a peripheral cutting edge is formed between the two chip removal grooves.

[0008] In a specific possible implementation manner, an end chip groove is provided on the ball end cutting edge.

[0009] In a specific possible implementation scheme, both the ball head rake face and the peripheral edge are provided with a false edge zone, and the false edge zone is connected through the ball head S-shaped cutting edge of the ball head cutting edge.

[0010] In a specific implementation scheme, the ball head rake surface is provided with a first clearance angle, a second clearance angle and a third clearance angle, the first clearance angle has an angle range of 3.5 to 5°, the second clearance angle has an angle range of 11 to 13°, and the third clearance angle has an angle range of 23 to 26°.

[0011] In a specific possible implementation manner, the ball end cutting edge is provided with a tooth expansion angle, and the angle range of the tooth expansion angle is 105-115°.

[0012] In a specific possible implementation manner, the helix angle of the peripheral blade ranges from 28 to 32°.

[0013] In a specific possible implementation manner, the ball end cutting edge is an S-shaped cutting edge.

[0014] In summary, the present application has the following beneficial technical effects: the ball head blade is an S-shaped blade, and the S-shaped blade line adopts a smooth curve to ensure uniform cutting between the ball head blade and the machined surface, reduce machining vibration and stress concentration, and the tool has high durability and can machine complex curved surfaces. The use of a variable tooth gap rake angle can effectively improve the distribution of cutting resistance, and the cutting in and out process is relatively smooth. It can also allow chips to be discharged smoothly, effectively preventing chips from adhering to the blade. The false blade band on the back blade surface increases the extrusion and finishing effect on the machined surface, and also improves the anti-chipping effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present application.

[0016] Figure 2 It is a schematic structural diagram of the front cutting surface of the ball head used in the embodiment of the present application.

[0017] Figure 3 It is a structural schematic diagram of an embodiment of the present application for reflecting a variable tooth gap front angle.

[0018] Figure numerals: 1. tool holder; 2. cutting part; 3. ball end cutting edge; 4. ball end rake face; 5. chip groove; 6. peripheral cutting edge; 7. ball end S-shaped cutting edge; 8. end chip groove; 9. false blade band; 10. arc ball end cutting edge. DETAILED DESCRIPTION

[0019] The following is combined with Figure 1-3This application is described in further detail.

[0020] The embodiment of the present application discloses a ball head mold milling cutter.

[0021] Reference Figure 1 and Figure 2 The ball-end mold milling cutter includes a shank 1 and a cutting part 2. The cutting part 2 includes a peripheral blade 6 and a ball-end blade part 3. The ball-end blade part 3 is provided with a ball-end S-shaped cutting edge 7. Two chip grooves 5 are provided along the outer peripheral wall of the cutting part 2. The two chip grooves 5 extend spirally from the shank to the ball-end blade part 3. A peripheral blade 6 is formed between the two chip grooves 5. The peripheral blade 6 can effectively reduce the cutting resistance during side cutting. The ball-end blade part 3 first contacts the machining surface of the workpiece to play a centering role. There are no sharp corners on the blade, and no stress concentration will occur to cause wear. The tool has high durability and can process complex curved surfaces. The chips generated during the machining process can be discharged along the chip groove 5, reducing the possibility of chips interfering with the machining surface of the workpiece.

[0022] Reference Figure 1 and Figure 2 The ball-end cutting edge 3 is provided with an end chip groove 8. The chips generated during the machining process are discharged along the end chip groove 8 to the chip groove 5. The end chip groove 8 guides the chips and effectively reduces the accumulation of chips. The spiral angle of the peripheral cutting edge 6 is in the range of 28 to 32°. In the embodiment of the present application, 30° is adopted. The ball-end S-shaped cutting edge 7 and the peripheral cutting edge 6 are both provided with a false blade band 9. The false blade band 9 is connected through the ball-end cutting edge 3 to achieve a smooth transition. The false blade band 9 on the back cutting edge increases the extrusion and finishing effect on the machined surface, and also improves the anti-chipping effect.

[0023] Reference Figure 1 and Figure 2 The ball head blade portion 3 is formed by the ball head rake face 4 and the ball head S-shaped cutting edge 7, and is ground from the maximum cross-section of the hemispherical blade portion to the direction of the minimum cross-section to form a straight back angle of the ball head S-shaped cutting edge 7 after the ball head mold knife is formed.

[0024] Reference Figure 2 and Figure 3 The two ball head rake faces 4 are provided with variable tooth clearance angles ε, which are set to -3°, -2° and -3°. The use of variable tooth clearance angles can effectively improve the distribution of cutting resistance, and the cutting-in and cutting-out processes are relatively stable.

[0025] Reference Figure 2 and Figure 3The ball head S-shaped cutting edge 7 is provided with a first clearance angle α, a second clearance angle β and a third clearance angle γ. The angle range of the first clearance angle α is 3.5-5°, the angle range of the second clearance angle β is 11-13°, and the angle range of the third clearance angle γ is 23-26°. The ball head cutting edge 3 is provided with a tooth expansion angle δ. The angle range of the tooth expansion angle δ is 105-115°. In the embodiment of the present application, the tooth expansion angle δ is 110°. The first clearance angle α, the second clearance angle β and the third clearance angle γ constitute three clearance angles, so the peripheral blade 6 also constitutes three clearance angles. The three clearance angles can reduce the friction between the ball head mold milling cutter and the processed surface. The three clearance angles of the ball head cutting edge 3 are the same as the three clearance angles of the peripheral blade 6. Both are processed by grinding wheel surface grinding and joint grinding. The processing efficiency is fast and the precision that the tool can achieve is higher.

[0026] The ball-end abrasive milling cutter in the embodiment of the present application processes mold steel HRC55, the detection equipment is zoller, the full R detection radius and contour, the scanning range is: 10~170°, and the sum of the inner and outer deviations of the contour does not exceed 0.01mm.

[0027] The ball-end blade portion 3 of the spiral blade with equal helix angle adopted in the embodiment of the present application is an S-shaped blade. Since the end blade (i.e., the S-shaped blade) passes through the axis of the milling cutter, it can be used for both axial feed and lateral feed, and can very conveniently process the inner cavity profile of the mold and other complex curved surfaces. The end blade is an S-shaped blade, and there is no sharp corner on the blade, so there will be no local concentrated wear, and the tool has high durability. During milling, since the end blade is an S-shaped cutting blade, the cutting-in and cutting-out processes are relatively smooth. Compared with a flat-blade ball-end end mill, when milling with an S-shaped ball-end end mill, not only are the three cutting force components relatively small, but the fluctuation range of the three force components is also relatively small during the cutting-in and cutting-out processes.

[0028] The implementation principle of the embodiment of the present application is as follows: the ball-end cutting edge 3 first contacts the machined surface of the workpiece to play a centering role. There are no sharp corners on the cutting edge, and no local concentrated wear will occur. The tool has high durability and can process complex curved surfaces. The chips generated during the processing can be discharged along the chip groove 5, reducing the possibility of chips interfering with the machined surface of the workpiece. The false blade band 9 on the back cutting edge increases the extrusion and finishing effect on the machined surface, and also improves the anti-chipping effect. The use of a variable tooth gap front angle can effectively improve the distribution of cutting resistance, and the cutting-in and cutting-out process is relatively smooth. The three back angles can reduce the friction between the ball-end mold milling cutter and the machined surface. The three back angles of the ball-end cutting edge 3 are the same as the three back angles of the peripheral blade 6. Both are processed by grinding wheel surface grinding and joint grinding. The processing efficiency is fast and the tool can achieve higher precision.

[0029] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A ball head mold milling cutter, characterized in that: The invention comprises a tool handle (1) and a cutting portion (2) arranged at one end of the tool handle (1), wherein the cutting portion (2) comprises a peripheral edge (6) and a ball-end edge portion (3), wherein the ball-end edge portion (3) is provided with a ball-end S-shaped cutting edge (7) and two ball-end rake surfaces (4), and wherein the ball-end rake surfaces (4) are provided with a variable tooth clearance rake angle.

2. The ball-end mold milling cutter according to claim 1, characterized in that: The variable backlash angles are set to -3°, -2° and -3°.

3. The ball-end mold milling cutter according to claim 1, characterized in that: The cutting portion (2) is provided with two chip removal grooves (5) along the outer peripheral wall. The two chip removal grooves (5) extend spirally from the tool handle (1) to the ball-end cutting edge (3). A peripheral cutting edge (6) is formed between the two chip removal grooves (5).

4. The ball-end mold milling cutter according to claim 1, characterized in that: The ball-end cutting edge portion (3) is provided with an end chip groove (8).

5. The ball-end mold milling cutter according to claim 1, characterized in that: The ball head rake face (4) and the peripheral edge (6) are both provided with a false edge zone (9), and the false edge zone (9) is connected via the ball head S-shaped cutting edge (7) of the ball head cutting edge portion (3).

6. The ball-end mold milling cutter according to claim 1, characterized in that: The ball head rake surface (4) is provided with a first clearance angle, a second clearance angle and a third clearance angle, wherein the first clearance angle has an angle range of 3.5 to 5°, the second clearance angle has an angle range of 11 to 13°, and the third clearance angle has an angle range of 23 to 26°.

7. The ball-end mold milling cutter according to claim 1, characterized in that: The ball-end cutting edge (3) is provided with a tooth expansion angle, and the angle range of the tooth expansion angle is 105-115°.

8. The ball-end mold milling cutter according to claim 1, characterized in that: The helical angle of the peripheral blade (6) ranges from 28 to 32 degrees.

9. The ball-end mold milling cutter according to claim 1, characterized in that: The ball-end blade portion (3) is an S-shaped blade.

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