A quick clamping device and method for numerical control machining of honeycomb parts

Abstract

The present invention belongs to product processing technology, and specifically relates to a rapid clamping device and method for CNC processing of honeycomb parts. The clamping and fixing during CNC processing of honeycomb cores are the first problems that need to be solved, which makes the clamping of honeycomb parts during CNC processing more difficult. The present invention includes a steel workbench and a plurality of holding and positioning columns, wherein the holding and positioning columns include a lateral holding section and a conical guide section, the lateral holding section is a cylindrical structure, the diameter of which is consistent with the diameter of the inscribed circle of the honeycomb grid, and the bottom end face of the conical guide section is adsorbed on the steel workbench; the device adopts an array of holding and positioning columns for clamping, and each array includes a holding and positioning column at the center position and a circumferentially surrounded holding and positioning column. It can not only provide sufficient holding force for the honeycomb parts to be processed, but also has the characteristics of high clamping and positioning accuracy, low cost, recycling, no damage, and no pollution.

Description

Technical Field

[0001] The invention belongs to product processing technology, and in particular relates to a quick clamping device and method for numerical control processing of honeycomb parts. Background Art

[0002] Honeycomb material is an advanced structural material with a wide range of applications and has become an important research object in the field of aerospace. Honeycomb structure, as the name suggests, is a hexagonal structure similar to the honeycomb built by bees in nature. Figure 1 shown.

[0003] At present, the use of honeycomb materials in various aircraft models in the domestic and foreign aviation industries is increasing. Due to the particularity of the honeycomb structure (weak rigidity, etc.), coupled with the functional and aerodynamic requirements of the fuselage structural parts, honeycomb sandwiches such as complex structure honeycombs and complex surface honeycombs are widely used, which brings great difficulties to the CNC machining of honeycomb parts. Among them, the clamping and fixation of the honeycomb sandwich during CNC machining is the first problem that needs to be solved, making the clamping of honeycomb parts during CNC machining more difficult.

[0004] Exploring rapid clamping devices and methods for CNC machining of honeycomb parts has become a research focus in the industry. The current main clamping methods include:

[0005] 1) Tape bonding clamping method

[0006] High adhesive strength is required for the tape. If the adhesive strength is too low, dust will be generated during the honeycomb processing process. This dust can easily cause the honeycomb to be loosely clamped, causing the honeycomb to be lifted and partially torn, resulting in the scrapping of the part. To improve the adhesive strength of the tape, a layer of release cloth is first laid on the adhesive surface of the honeycomb material and cured before clamping. This will make it too firmly fixed, making it difficult to disassemble the honeycomb after processing. Secondly, once the honeycomb structure is bonded to the processing platform, it is difficult to adjust its position. Therefore, the honeycomb structure may wrinkle during processing, making it difficult to guarantee processing accuracy.

[0007] 2) Vacuum adsorption method

[0008] This method is also known as the diaphragm method. Its principle is to bond the honeycomb structure to a diaphragm made of plastic film or glass fiber reinforced plastic with an adhesive, and then fix the diaphragm to the processing platform by vacuum adsorption.

[0009] This method is similar to double-sided tape bonding, but it offers a relatively strong holding force, allowing for heavy cutting of honeycomb structures. However, its drawbacks are also obvious. First, this method still requires line contact with the honeycomb, which can lead to similar results as double-sided tape bonding. Second, the use of a diaphragm for securing the parts is cumbersome, and vacuuming is time-consuming, resulting in low production efficiency. Therefore, this method is somewhat effective for machining certain specialized parts, but is not suitable for mass production.

[0010] In summary, in order to solve the deficiencies and defects of the above-mentioned various clamping and fixing methods, it is urgent to develop a new rapid clamping device and method suitable for CNC machining of honeycomb parts. Summary of the Invention

[0011] The purpose of the present invention is to provide a quick clamping device and method for CNC machining of honeycomb parts to overcome the current problems of difficulty in disassembling honeycombs and low production efficiency.

[0012] The present invention proposes a rapid clamping device for CNC machining of honeycomb parts, which includes a steel workbench and a plurality of holding and positioning columns, wherein the holding and positioning columns include a lateral holding section and a conical guide section, the lateral holding section being a cylindrical structure with a diameter consistent with the diameter of the inscribed circle of the honeycomb cells, and the bottom end surface of the conical guide section being adsorbed on the steel workbench; the device uses an array of holding and positioning columns for clamping, and each array includes a holding and positioning column at the center position and holding and positioning columns surrounding the circumference.

[0013] Advantageously, the height of the holding and positioning pillars is H=h-(5-10) mm, where h is the height of the honeycomb cells.

[0014] Advantageously, the height H1 of the lateral holding section and the height H2 of the conical guiding section are such that H1 / H2=5-10.

[0015] Advantageously, the cylindricity of the lateral holding segment is not less than 0.05 and the surface roughness Ra is less than 0.8.

[0016] Advantageously, the tapering of the tapered guide section is 8-12 degrees, and the bottom end surface must be at least 28mm 2 The area of ​​a circle.

[0017] Advantageously, the flatness of the bottom end surface is not less than 0.02, the surface roughness Ra is less than 0.8, and the perpendicularity to the outer cylindrical surface of the lateral holding section is not less than 0.03.

[0018] Advantageously, the material of the retaining and positioning pillar is preferably neodymium iron boron magnet, and the surface is chemically passivated.

[0019] Advantageously, the sharp edges and corners of the retaining and positioning posts need to be rounded to ensure a smooth transition.

[0020] Advantageously, for regions with an aspect ratio greater than 3, a rectangular array holding solution is adopted, and for regions with an aspect ratio less than 3, a five-point array holding solution is adopted.

[0021] The present invention also provides a rapid clamping method for CNC machining of honeycomb parts, which adopts the above-mentioned rapid clamping device and includes the following steps:

[0022] S1. Preparation of retaining columns

[0023] Determine the array layout of the clamping according to the size of the honeycomb parts, and process the holding and positioning columns according to the height and diameter of the honeycomb cells at each clamping location;

[0024] S2. Clean the steel workbench

[0025] Clean the steel workbench with a clean silk cloth to ensure it is free of chips and oil;

[0026] S3. Clamping

[0027] Place the honeycomb to be processed on the steel workbench and complete the array installation at each position according to the array layout designed in S1. First install the central holding and positioning columns, and then install the circumferential holding and positioning columns in sequence.

[0028] Beneficial effects of the present invention: The present invention is a fixing method between end face fixing and complete fixing, which can provide sufficient holding force for the honeycomb parts to be processed, and has the characteristics of high clamping and positioning accuracy, low cost, recycling, no damage, and no pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The illustrative examples, together with the preferred mode of use, further objects and description thereof, will be best understood by reference to the following detailed description of examples of the invention when read in conjunction with the accompanying drawings, in which:

[0030] Figure 1 Schematic diagram of honeycomb structure;

[0031] Figure 2 This is a schematic diagram of the quick clamping device of the present invention;

[0032] Figure 3 Structural diagram of the retaining and positioning column 1;

[0033] Figure 4 A holding solution for an embodiment with a length-to-width ratio greater than 3 (rectangular);

[0034] Figure 5 For an embodiment retaining solution with a length to width ratio of less than 3 (five-point type);

[0035] Figure 6Schematic diagram of the arrangement of retaining and positioning columns for a single array. DETAILED DESCRIPTION

[0036] The disclosed examples will be described more fully with reference to the accompanying drawings, in which some (but not all) of the disclosed examples are shown. In fact, many different examples can be described and these examples should not be construed as limited to the examples set forth herein. Instead, these examples are described so that this disclosure will be thorough and complete and will fully convey the scope of the disclosure to those skilled in the art.

[0037] The present invention provides a quick clamping device for CNC machining of honeycomb parts, based on the attraction properties of magnetic materials and the principle of tribology. Figure 2 At the same time, the device and method have a shape-preserving function for the honeycomb cells 3. Since the holding and positioning columns 2 are magnetic, their bottom end faces 4 will be firmly magnetically adsorbed on the steel workbench 1 and positioned. A magnetic field enhancement device is also provided at the bottom of the steel workbench 1 (not shown, which can be opened and adjusted as needed). Adjacent holding and positioning columns 1 attract each other to clamp the side walls of the honeycomb cells 3 and generate a positive pressure Fn. When the machining cutting force causes the honeycomb parts to be processed to move up and down, the friction force f brought by the positive pressure Fn is combined to provide a vertical holding force Fz. At the same time, a group of planes are formed by relying on multiple holding and positioning columns 1 to be firmly adsorbed on the steel workbench 1, realizing end face clamping and positioning, thereby limiting the degrees of freedom of Fx, Fy, Mx, My, and Mz, and completing reliable clamping and positioning.

[0038] like Figure 3 The magnetic holding and positioning column 2 is a rotating body structure, mainly comprising a cylindrical lateral holding section 6 and a conical tapered guide section 5, and the tapered guide section 5 has a bottom end face 4. The total height H of the holding and positioning column 2 is determined by the final height h of the honeycomb cell 3 to be processed, generally H = h-(5-10), unit mm; the main features of the lateral holding section 6 are that the cylindricity is not less than 0.05, the surface roughness Ra is less than 0.8, and the diameter D is equal to the inscribed circle diameter of the hexagonal honeycomb cell 3 (ensuring that after clamping, the lateral holding section 2 has ideal linear contact with the six side walls of the honeycomb cell 3, bringing shape retention function while increasing the strength of the weak rigidity honeycomb cell 6); the tapered guide section 5 is to ensure that the holding and positioning column 1 can be smoothly inserted into the honeycomb cell 3, and its taper is generally 8-12 degrees. At the same time, the angle value needs to ensure that the bottom end face 4 has a diameter of not less than 28mm 2 The bottom end surface 4 is positioned against the steel workbench 1, with a flatness of not less than 0.02, a surface roughness Ra of less than 0.8, and a perpendicularity to the outer cylindrical surface of the lateral holding section 6 of not less than 0.03; in addition, generally, the relationship between the height H1 of the lateral holding section 6 and the height H2 of the tapered guide section 2 is H1 / H2=5~10.

[0039] To ensure that the retaining and positioning pins 1 have high magnetic energy product and strong magnetic force, their material is preferably neodymium iron boron magnets. At the same time, to prevent oxidation during use, the surface needs to be chemically passivated. To prevent the retaining and positioning pins 1 from damaging the honeycomb, their sharp edges and corners need to be rounded and ensure a smooth transition.

[0040] A series of retaining and positioning columns 2 of height H can be prefabricated using a priority number system. For optimal clamping and retention, at least seven retaining and positioning columns 2 are typically selected to form a group and distributed within the group. The distance between groups must not exceed 12 times the diameter D of the lateral retaining segment 6.

[0041] like Figure 4-5 In the two embodiments, a rectangular holding solution with a length-to-width ratio greater than 3 and a five-point holding solution with a length-to-width ratio less than 3 are provided.

[0042] After the CNC machining is completed, in order to ensure that all the retaining and positioning columns 1 are removed, the light transmission method can be used for inspection, that is, a strong flashlight is used to illuminate the honeycomb grid 6 axially from one side, and observe whether there are black spots or shadows in the back after projection. The location with black spots and shadows proves that the retaining and positioning columns have not been removed.

[0043] In one embodiment, when the quick clamping device for numerically controlling honeycomb parts of the present invention is used for clamping processing, the following steps are included:

[0044] 1) Preparation of retaining and positioning columns

[0045] The diameter of the inscribed circle of the honeycomb cells 3 to be processed was measured to be 10 mm, and the diameter D of the lateral holding section 6 of the holding and positioning column 1 was obtained to be 10 mm. The final height h of the honeycomb cells 6 to be processed was measured to obtain the total height H of the holding and positioning column as H = h-5 (this example uses plane processing, so the final height h of the honeycomb cells 6 to be processed is consistent). Furthermore, the cone angle of the tapered guide section 2 was set to 8 degrees, and H1 / H2 was set to 5, and the sharp edges were rounded and smoothed.

[0046] 2) Clean the steel workbench 1 with a clean silk cloth to ensure that there are no foreign matter such as chips, oil stains, etc.

[0047] 3) Place the honeycomb to be processed on the steel workbench 1 and follow the typical clamping and holding scheme. Since the length and width ratio of the honeycomb to be processed A / B is equal to 1, the honeycomb to be processed is selected. Figure 5 The five-point clamping and holding solution shown in the figure first completes the installation of a group of seven holding and positioning columns 2. When installing each group, the central holding and positioning columns 2 must be installed first, and then the circumferential holding and positioning columns 2 are installed in sequence.

[0048] 4) Complete the CNC cutting of the honeycomb parts to be processed according to the process plan, and check the processing quality of the honeycomb parts according to the drawings, including size, surface quality, etc.;

[0049] 5) Disassembly: Remove the retaining and positioning columns 2 of each group from the outside to the inside and from the outside to the inside;

[0050] 6) Use a strong flashlight to illuminate the honeycomb cells 3 from one side along their axial direction, and observe whether there are any dark spots or shadows on the back of the projection. If there are any dark spots or shadows, it means that the retaining and positioning posts 2 have not been removed. Once all the retaining and positioning posts 2 are removed, the entire work is completed.

[0051] Different examples of the systems, apparatuses, and methods disclosed herein include various components, features, and functions. It should be understood that various examples of the systems, apparatuses, and methods disclosed herein may include any of the components, features, and functions of any of the other examples of the systems, apparatuses, and methods disclosed herein in any combination or any subcombination, and all such possibilities are intended to fall within the scope of the present invention.

[0052] The description of various advantageous arrangements has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the examples disclosed. Many modifications and variations will be apparent to those skilled in the art. In addition, different advantageous examples may describe different advantages compared to other advantageous examples. The selected example or examples are chosen and described to best illustrate the principles of the examples, their practical application, and to enable those skilled in the art to understand the disclosure with various examples with various modifications suitable for the particular use contemplated.

Claims

1. A quick clamping device for CNC machining of honeycomb parts, characterized in that: The device comprises a steel workbench (1) and a plurality of holding and positioning columns (2), wherein the holding and positioning columns (2) are made of a neodymium iron boron magnet and are subjected to a surface chemical passivation treatment, and comprise a lateral holding section (6) and a conical guide section (5), wherein the lateral holding section (6) is a cylindrical structure, and the diameter thereof is consistent with the diameter of the inscribed circle of the honeycomb cell (3), the height H1 of the lateral holding section (6), the height H2 of the conical guide section (5), H1 / H2=5-10, the bottom end surface (4) of the conical guide section (5) is adsorbed on the steel workbench (1), the taper of the conical guide section (5) is 8-12 degrees, and it is required to ensure that the bottom end surface (4) has a radius of not less than 28 mm. 2 The device adopts an array of retaining and positioning columns (2) for clamping, and each array includes a retaining and positioning column (2) at a central position and retaining and positioning columns (2) surrounding the circumference; the array layout of the clamping is determined according to the size of the honeycomb part, and the excess retaining and positioning columns (2) are processed according to the height and diameter of the honeycomb cells (3) at each clamping position; for an area with a length-to-width ratio greater than 3, a rectangular array retaining solution is adopted; for an area with a length-to-width ratio less than 3, a five-point array retaining solution is adopted; when the array is installed, the middle retaining and positioning column (2) is installed first, and then the retaining and positioning columns (2) in the circumference are installed in sequence.

2. The quick clamping device according to claim 1, characterized in that: The height of the holding and positioning column (2) is H=h-(5-10) mm, where h is the height of the honeycomb cells (3).

3. The quick clamping device according to claim 1, characterized in that: The cylindricity of the lateral holding section (6) is not less than 0.05, and the surface roughness Ra is less than 0.

8.

4. The quick clamping device according to claim 1, characterized in that: The flatness of the bottom end surface (4) is not less than 0.02, the surface roughness Ra is less than 0.8, and the perpendicularity with the outer cylindrical surface of the lateral holding section (6) is not less than 0.

03.

5. The quick clamping device according to claim 1, characterized in that: The sharp edges and corners of the retaining and positioning column (2) must be rounded to ensure a smooth transition.

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