A type of milling cutter for processing large wood carving furniture

Abstract

This invention relates to a milling cutter for large-scale wood carving furniture processing, belonging to the field of furniture manufacturing. The milling cutter of this invention includes a cutter body, which comprises a shank, a cutting edge, and a vibration shaft assembly for applying a horizontal excitation force to the cutter body. The vibration shaft assembly includes a long shaft, which includes a shank located above the shank and a light shaft coaxially connected to the shank. Multiple eccentric blocks are fixedly connected to the lower end of the light shaft. This invention, through optimized design of the existing milling cutter structure and the application of a horizontal excitation force to the cutter body by installing the vibration shaft assembly, significantly improves chip removal during milling, especially suitable for milling deep holes, preventing surface burning. Furthermore, it can be used for long-term continuous milling operations with good implementation results.

Description

Technical Field

[0001] This invention relates to the field of furniture processing technology, specifically a milling cutter for processing large wood-carved furniture. Background Technology

[0002] In the furniture industry, large-scale wood carvings, especially three-dimensional sculptures, are large in size, with the largest carved cross-section typically exceeding 1 meter. 2 Its processing is very complex, with strict requirements for material selection and rough processing.

[0003] For large-scale wood-carved furniture, the raw wood is cut, roughly polished, and roughly milled into blanks. After surface treatment as needed, the next step of carving and subsequent processing can begin. The milling cutters used for rough milling of these large wood-carved furniture blanks are much larger than those on ordinary milling machines, with the diameter of the cutter shank / head generally exceeding 3cm. While such large cutters offer high processing efficiency, they usually suffer from poor chip removal. Compressed air is generally needed to assist in blowing away wood chips. However, for excessively thick blanks, such as milling operations with a depth exceeding 3cm, milling must be stopped after a period of time or the cutter speed reduced, and other methods used to assist in chip removal. Otherwise, the milled surface is prone to burning.

[0004] Based on this, the present invention is proposed. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing a milling cutter for processing large wooden furniture, the technical solution of which is as follows:

[0006] A milling cutter for processing large wooden furniture includes a cutter body, which includes a shank and a cutting edge, and also includes an excitation shaft assembly for applying a horizontal excitation force to the cutter body.

[0007] As a further embodiment of the present invention, the handle of the tool holder is provided with an eccentric block rotating cavity in the center of the handle portion, the excitation shaft assembly includes a long shaft, the long shaft includes a shaft handle located above the tool holder and an optical shaft coaxially connected to the shaft handle, the lower end of the optical shaft is fixedly connected to a plurality of eccentric blocks, all of which are located inside the eccentric block rotating cavity; the optical shaft is rotatably connected to the upper end of the tool holder.

[0008] As a further embodiment of the present invention, a bearing is embedded in the upper end of the tool holder, and the optical axis is rotatably connected to the tool holder by means of the bearing.

[0009] As a further embodiment of the present invention, the upper end of the tool holder is provided with a T-shaped hole for mounting a bearing, and the T-shaped hole is connected to the rotating cavity of the eccentric block.

[0010] As a further embodiment of the present invention, the eccentric block is provided in three parts.

[0011] As a further embodiment of the present invention, the inner wall of the eccentric block rotating cavity is provided with a spiral groove.

[0012] As a further aspect of the present invention, when the spiral groove rotates clockwise, the optical axis rotates counterclockwise.

[0013] As a further aspect of the present invention, the rotational speed of the milling cutter body is greater than the rotational speed of the long shaft.

[0014] As a further embodiment of the present invention, the orthographic projections of two adjacent eccentric blocks are partially overlapped.

[0015] As a further aspect of the present invention, the eccentric block rotating cavity is filled with a non-Newtonian fluid.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] This invention discloses a milling cutter for large-scale wood carving furniture processing. By optimizing the existing milling cutter structure and installing a vibration shaft assembly to apply a horizontal vibration force to the milling cutter body, the chip removal effect during milling is significantly improved. It is especially suitable for milling deep holes (hole depth exceeding 3cm) and will not cause the milling surface to burn. In addition, it can be used for long-term continuous milling operations with good implementation results. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a milling cutter used for processing large wooden furniture.

[0019] Figure 2 This is a schematic diagram showing the connection between the milling cutter body and the excitation shaft assembly.

[0020] Figure 3 This is a schematic diagram of the internal structure of the milling cutter body.

[0021] Figure 4 This is a schematic diagram of the orthographic projection of three eccentric blocks.

[0022] Figure 5 The graph shows the relationship between the K value and the relative scorch rate P1. Detailed Implementation

[0023] The present invention will be described in detail below with reference to specific embodiments. These embodiments are merely some, not all, implementations of the present invention. All other implementations obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0024] Example 1

[0025] A type of milling cutter for processing large wooden furniture, such as Figure 1, 2 As shown, it includes a milling cutter body 10, which includes a shank 11 and a cutting edge 12.

[0026] A milling cutter for processing large wooden furniture also includes an excitation shaft assembly 20 for applying a horizontal excitation force to the milling cutter body 10.

[0027] The excitation shaft assembly 20 serves as the excitation source, providing a horizontal excitation force to the milling cutter body 10 upon startup. This facilitates chip removal during milling, making it particularly suitable for milling deep holes (depth exceeding 3cm) without causing surface burning. Furthermore, it allows for continuous milling for up to 19 minutes without needing to stop milling or reduce the cutter speed. Only low-pressure compressed air (1-4 bar) is required to blow away accumulated wood chips from the blank surface; high-pressure compressed air (greater than 30 bar) directed at the cutter edge is unnecessary for chip removal.

[0028] Example 2

[0029] Based on Example 1, such as Figures 2-4 As shown, the handle 11 has an eccentric block rotating cavity 13 in the center of the handle portion. The excitation shaft assembly 20 includes a long shaft, which includes a shaft handle 21 located above the handle 11 and an optical shaft 22 coaxially connected to the shaft handle 21. The lower end of the optical shaft 22 is fixedly connected to a plurality of eccentric blocks 23, all of which are located inside the eccentric block rotating cavity 13. The optical shaft 22 is rotatably connected to the upper end of the handle 11.

[0030] In this example, the tool holder 11 is connected to an external power head, and the shaft shank 21 is connected to another external power head. Both rotate under the drive of their respective power heads and do not interfere with each other. The rotational speed of the milling cutter body 10 is not equal to the rotational speed of the long shaft, which results in relative rotation between the optical shaft 22 and the tool holder 11. Thus, the optical shaft 22 drives the eccentric block 23 to rotate, generating centrifugal force, which causes the milling cutter body 10 to vibrate at high frequency. This design ensures that the excitation direction is horizontal vibration, rather than vertical vibration. If vertical vibration is generated, it will not only not help much in promoting chip removal, but will also easily damage the tool holder 11 and create safety hazards.

[0031] The rotational speed of the milling cutter body 10 is generally 600–1200 r / min, and the rotational speed of the long shaft is generally 300–800 r / min. The rotational speed of the long shaft needs to be less than that of the milling cutter body 10. On the one hand, this is mainly because the long shaft is limited by its size, and its rotational speed cannot be too high, otherwise it will be prone to fatigue and aging. On the other hand, multiple studies have found that if the rotational speed of the long shaft is greater than that of the milling cutter body 10, it will cause excessive excitation force and easily generate resonance. Not only will the subsequent bearing 30 be easily damaged, but the milling cutter body 10 and the long shaft also have a certain probability of breaking. Once the high-speed rotating milling cutter body 10 breaks, there is a huge safety risk.

[0032] Example 3

[0033] In embodiment 2, by embedding a bearing 30 at the upper end of the tool holder 11, the optical axis 22 and the tool holder 11 are rotatably connected by mounting the bearing 30.

[0034] In some embodiments, to facilitate the installation of the bearing 30, a T-shaped hole 15 for installing the bearing 30 is provided at the upper end of the tool holder 11, and the T-shaped hole 15 is connected to the eccentric block rotating cavity 13.

[0035] Example 4

[0036] In embodiment 2, three eccentric blocks 23 are provided. The inner wall of the eccentric block rotation cavity 13 is provided with a spiral groove 14.

[0037] During processing, the T-shaped hole 15 is machined first, then the eccentric block rotating cavity 13 is machined, and then the spiral groove 14 is machined using a boring tool. When installing the eccentric block 23, the optical shaft 22 with the bearing 30 and the eccentric block 23 installed is inserted into the eccentric block rotating cavity 13 after passing through the T-shaped hole 15. Then, non-Newtonian fluid is filled into the eccentric block rotating cavity 13, and finally the bearing 30 is installed for sealing.

[0038] The eccentric block rotating cavity 13 is filled with a non-Newtonian fluid. A non-Newtonian fluid can also be made using starch and water in a 1:3 ratio, but this has two drawbacks. First, water may cause rust inside the eccentric block rotating cavity 13 after long-term use; therefore, an organic solvent is preferred. Second, the starch-water system of non-Newtonian fluid has a relatively low initial viscosity and is not viscous enough, requiring a high rotational speed to achieve the "hardening" effect.

[0039] Therefore, after extensive testing, the non-Newtonian fluid used in this invention is prepared by mixing starch, acetone, iron filings and calcium-based grease in a mass ratio of 2.5:1:0.2:0.07.

[0040] When the spiral groove 14 rotates clockwise, the optical axis 22 rotates counterclockwise.

[0041] The orthographic projections of two adjacent eccentric blocks 23 are partially overlapping, and the ratio of the overlapping area to the orthographic projection of the eccentric block 23 is K, preferably 11%.

[0042] Example 5

[0043] The only difference between this example and Example 4 is that in this example, when the spiral groove 14 rotates clockwise, the optical axis 22 also rotates clockwise; all other aspects are the same.

[0044] Example 6

[0045] The only difference between this example and Example 4 is that the spiral groove 14 is not provided in this example; all other aspects are the same.

[0046] Example 7

[0047] The only difference between this example and Example 4 is that the major axis does not rotate in this example; everything else is the same.

[0048] Example 8

[0049] In this example, the orthographic projections of two adjacent eccentric blocks 23 are tested based on whether they overlap. If they overlap, the ratio of the overlapping area to the orthographic projection of the eccentric block 23 is K. The value of K changes according to the "Characteristic Test of Chip Removal Performance of Milling Cutters". All tests are conducted with continuous milling for 15 minutes. The corresponding curve of the relative scorch rate P1 is shown in the figure. Figure 5 ,Depend on Figure 5 It can be seen that K is preferably 11%.

[0050] End Mill Chip Removal Performance Characterization Test

[0051] Birch trunks were used as test wood blanks. Milling was performed using a milling cutter (such as the large wood carving furniture milling cutter described in Example 4) to a depth of 5 cm, continuously for 10–30 minutes. During milling, compressed air at 2 bar was used to blow away sawdust near the milling cutter to prevent its accumulation. After milling, compressed air was used to clean the milled groove (the serpentine groove milled by the milling cutter on the wood blank). Then, the surface dust of the milled groove was wiped dry with a damp cloth. The presence of charred areas on the groove surface was observed. If present, the area of ​​the charred areas was calculated using a grid method. The total area of ​​all charred areas in the groove was calculated as S1. The surface area of ​​the groove was S0. The relative charring rate P1 = 2000 * S1 / S0. Because it was found in the experiment that there was almost no charring in the first 3 minutes of milling, and the charred area was limited, the relative charring rate P1 was used for easy comparison. The experimental results are shown in Table 1:

[0052] Table 1

[0053]

[0054] Example 9

[0055] The only difference between this example and Example 4 is that, in this example, the non-Newtonian fluid is replaced with water; all other aspects are the same.

[0056] Example 10

[0057] The only difference between this example and Example 4 is that, in this example, the non-Newtonian fluid is replaced with air (that is, the eccentric block rotating cavity 13 is empty), and all other aspects are the same.

[0058] End Mill Stability Characterization Test

[0059] The milling cutter body 10 rotates at 1200 r / min, and the long shaft rotates at 800 r / min. First, the maximum noise level in decibels during milling of the wood blank is measured, denoted as A0. Then, at the above rotational speed, limestone is milled for a cumulative milling time of 100 hours, which constitutes a high-strength fatigue test on the milling cutter. Afterward, the milling cutter is used to mill the wood blank again, and the maximum noise level in decibels during milling is measured, denoted as A1. ΔA = A1 – A0. The larger ΔA is, the more unstable the milling cutter system is after the high-strength fatigue test, and the more likely it is to emit a harsh noise during high-speed rotation, which is detrimental to the stable operation of the milling cutter. The test results are shown in Table 2.

[0060] Table 2

[0061]

[0062]

[0063] In Table 2, the reference example is an existing milling cutter, whose tool holder 11 is machined into a hollow tool holder.

[0064] In this invention, the main factor affecting ΔA is that if the wear caused by long-term eccentric vibration is too large, it can easily lead to system instability, thereby generating harsh noise.

[0065] Example 11

[0066] The only difference between this example and Example 4 is that the non-Newtonian fluid used in this example is prepared by mixing starch, acetone, and iron filings in a mass ratio of 2.57:1:0.2; all other aspects are the same.

[0067] Example 12

[0068] The only difference between this example and Example 4 is that the non-Newtonian fluid used in this example is prepared by mixing starch, acetone, iron filings and soybean oil in a mass ratio of 2.5:1:0.2:0.07.

[0069] Non-Newtonian Fluid Characterization Experiments

[0070] The viscosity and shear rate of the fluid were measured using a rheometer, and the results are shown in Table 3.

[0071] Table 3

[0072]

[0073] As shown in Table 3, the viscosity of the non-Newtonian fluid in Example 4 increases sharply with the increase of shear rate. This property means that when the speed difference between the milling cutter body 10 and the long shaft changes, the non-Newtonian fluid can still play a certain level of excitation force transmission effect and meet the milling requirements of the milling cutter body 10 at different speeds.

[0074] Furthermore, it should be understood that those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A large wood carving furniture processing milling cutter, comprising a milling cutter body (10), the milling cutter body (10) comprises a shank (11) and a cutting edge part (12), characterized in that: The excitation shaft assembly (20) is used to apply horizontal excitation force to the milling cutter body (10); The eccentric block rotating cavity (13) is arranged in the center of the shank of the tool holder (11), the excitation shaft assembly (20) comprises a long shaft, the long shaft comprises a shaft shank (21) arranged above the tool holder (11), a light shaft (22) coaxially connected with the shaft shank (21), a plurality of eccentric blocks (23) fixedly connected with the lower end of the light shaft (22), and the eccentric blocks (23) are arranged in the eccentric block rotating cavity (13); and the light shaft (22) is rotationally connected with the upper end of the tool holder (11). The rotating speed of the milling cutter body (10) is greater than the rotating speed of the long shaft. The eccentric block rotating cavity (13) is filled with a non-Newtonian fluid.

2. The milling cutter for large wood carving furniture processing according to claim 1, characterized in that: The upper end of the tool holder (11) is embedded with a bearing (30), and the light shaft (22) is rotationally connected with the tool holder (11) through the bearing (30).

3. The milling cutter for large wood carving furniture processing according to claim 2, characterized in that: The upper end of the tool holder (11) is provided with a T-shaped hole (15) for mounting the bearing (30), and the T-shaped hole (15) is communicated with the eccentric block rotating cavity (13).

4. The milling cutter for large wood carving furniture processing according to claim 1, characterized in that: The eccentric block (23) is provided with three blocks.

5. The milling cutter for large wood carving furniture processing according to claim 1, characterized in that: The inner wall of the eccentric block rotating cavity (13) is provided with a spiral groove (14).

6. The milling cutter for large wood carving furniture processing according to claim 5, characterized in that: When the rotation direction of the spiral groove (14) is clockwise, the rotation direction of the light shaft (22) is counterclockwise.

7. The milling cutter for large wood carving furniture processing according to claim 4, characterized in that: The orthographic projection of the upper and lower adjacent eccentric blocks (23) is partially overlapped.

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