Precision machining method for PEEK low-rigidity thin-wall cabin

Abstract

The invention discloses a PEEK low-rigidity thin-wall cabin precision machining method, and relates to the technical field of thin-wall cabin precision machining.The method comprises the steps that after a workpiece is aligned, clamped and fixed, the position, close to a machining part, of the upper end of the workpiece is sleeved with a rubber leather with certain elasticity; the mode of finish turning of the outer circle is changed into the mode that the mandrel is matched with the inner hole of the workpiece to press the step of the cavity from the original top turning clamping mode; the outer circle, the end face and the inner hole are combined and machined through one procedure. According to the milling process, rubber suspension fixing is adopted for machining, the vibration effect is good in the machining process of the weak-rigidity high polymer material, operation is easy, materials are easy to obtain, and wide application can be achieved.

Description

Technical Field

[0001] This invention relates to the field of precision machining technology for thin-walled cabins, and more specifically, to a precision machining method for PEEK low-rigidity thin-walled cabins. Background Technology

[0002] The cabin structure is a thin-walled component with high dimensional accuracy. PEEK, also known as polyetheretherketone, is used as the cabin material. It is a linear aromatic polymer compound and a special engineering plastic, characterized by high temperature resistance, good self-lubrication, and chemical corrosion resistance. However, due to the polymeric properties and structural form of the workpiece material, it is prone to deformation during processing, making it difficult to guarantee the required precision. Because of the high dimensional accuracy and complex workpiece cavity, the shrinkage range of injection molding or 3D printing materials cannot meet the workpiece requirements. Therefore, machining is used to achieve the drawing requirements. However, compared to metal materials, the processing performance of PEEK material is significantly different. Its coefficient of thermal expansion is three times that of aluminum alloy, and its elastic modulus is about one-twentieth of that of aluminum alloy. This means that the material is greatly affected by temperature during processing, and its strength and rigidity are low, while its elasticity is high, causing significant challenges in the clamping and cutting processes of machining.

[0003] Currently, the application of PEEK materials in China is in its initial stage. Research on PEEK machining is limited, and there is little research on machining workpieces with large cavities, thin walls, and high precision structural characteristics for cabins. No suitable machining solutions have been found for reference, and conventional clamping methods are used for machining. Machining often involves machining the workpiece in a deformed state. While the dimensions are acceptable before disassembly, the roundness of the workpiece exceeds tolerances after disassembly, leading to dimensional errors. To ensure dimensional accuracy in cabin machining, it is necessary to address the issues of clamping deformation and vibration during the machining process, taking into account the material's characteristics.

[0004] The defect of missing material when the hull is milled with an opening groove is because the workpiece structure is a broken cantilever after the opening groove is milled. It has poor rigidity and high material elasticity, which makes it very easy for the tool to "deflect" and cause vibration. The vibration will cause the tool to bounce, and the tool swings during the cutting of the workpiece, resulting in machining defects.

[0005] When precision machining the two holes φ150H8 and φ150+0.08+0.03 on the lathe, a self-made lathe clamp is used. The lathe is divided into two parts: a sleeve and a clamping nut. The sleeve is clamped on the lathe's three-jaw chuck. The entire cabin body is inserted into the sleeve, with a small clearance fit between the sleeve and the outer diameter of the cabin body. Finally, the clamping nut is tightened onto the sleeve to axially compress the cabin body (e.g., ...). Figure 3As shown), the original clamping method has the following three problems: 1) The machine tool clamp sleeve and the outer circle of the compartment are fitted with a small clearance. If the roundness of the outer circle is not up to standard, the sleeve will correct the roundness of the compartment section. After the machining is completed, the compartment section is taken out of the machine tool clamp. Under natural conditions, the roundness of the inner hole is out of tolerance, resulting in deformation and copying, which leads to dimensional deviation; 2) The method of tightening with a pressure nut is inefficient; 3) Excessive clamping force can easily cause workpiece deformation. The workpiece is machined under the preload of the end face and has a different shape when not in use.

[0006] Common clamping methods for machining chambers have the following drawbacks: Common clamping methods result in severe deformation, requiring constant alignment and adjustment of the workpiece, leading to low clamping efficiency and an inability to guarantee dimensional accuracy. Existing clamping methods lack anti-vibration measures, resulting in defects such as missing material during machining. Summary of the Invention

[0007] The purpose of this invention is to provide a precision machining method for PEEK low-rigidity thin-walled cabins, which can overcome the above-mentioned defects of existing xxx.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] This specification provides a method for precision machining of PEEK low-rigidity thin-walled cabins, including...

[0010] After the workpiece is aligned, clamped, and fixed, a rubber sleeve with a certain degree of elasticity is used on the upper end of the workpiece near the machining area.

[0011] The finishing of the outer diameter was changed from the original top-mounted clamping to the use of a mandrel to engage with the inner hole of the workpiece and press the cavity steps together.

[0012] The outer circle, end face, and inner hole are processed in a single operation.

[0013] Based on the above technical solution, this specification can achieve the following technical effects:

[0014] The milling process of the aforementioned PEEK low-rigidity thin-walled cabin precision machining method utilizes rubber suspension fixation, which effectively reduces vibration during the machining of weakly rigid polymer materials. The operation is simple, the materials are readily available, and it can be widely applied. The low-stress clamping method used in the turning process reduces deformation caused by clamping forces. Machining the part under no clamping force reduces the difference between measurements taken while the workpiece is clamped and in its natural state after disassembly. The turning process uses absorbent sponges inserted into the workpiece's internal cavity, effectively preventing vibration during the machining of outer diameters and inner holes. This method is simple, convenient, and uses readily available materials, resulting in good economic efficiency. Attached Figure Description

[0015] Figure 1This is a structural schematic diagram of the cabin drawing proposed in this invention;

[0016] Figure 2 This is a schematic diagram of the cabin skid phenomenon proposed in this invention;

[0017] Figure 3 This is a schematic diagram of the machining process for the inner bore of the cabin proposed in this invention;

[0018] Figure 4 This is a diagram illustrating the milling process proposed in this invention.

[0019] Figure 5 This is a clamping diagram of the stepped surface of the molding cavity proposed in this invention;

[0020] Figure 6 This is a clamping diagram of the stepped surface of the molding cavity proposed in this invention;

[0021] Figure 7 This is a photograph of the sponge inserted into the inner cavity according to the present invention;

[0022] Figure 8 This is a diagram illustrating the low-stress clamping process for precision machining of the inner bore of the compartment section proposed in this invention. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and are not to a precise scale, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0024] It should be noted that, in order to clearly illustrate the content of this invention, several embodiments are provided to further explain different implementations of the invention. These embodiments are enumerated rather than exhaustive. Furthermore, for the sake of brevity, content mentioned in the preceding embodiments is often omitted in the following embodiments. Therefore, content not mentioned in the later embodiments can be referred to in the preceding embodiments.

[0025] Please refer to Figures 1 to 8 An embodiment of this specification provides a precision machining method for a PEEK low-rigidity thin-walled cabin, which includes, after the workpiece is aligned, clamped and fixed, using a rubber sleeve with a certain elasticity at the upper end of the workpiece near the machining area.

[0026] The finishing of the outer diameter was changed from the original top-mounted clamping to the use of a mandrel to engage with the inner hole of the workpiece and press the cavity steps together.

[0027] The outer circle, end face, and inner hole are processed in a single operation.

[0028] Milling operations utilize rubber suspension for effective vibration control of weakly rigid polymer materials during machining. This method is simple to operate, uses readily available materials, and has wide applicability. Turning operations employ a low-stress clamping method, reducing deformation caused by clamping forces. Machining the part under no clamping force minimizes the difference between measurements taken while the workpiece is clamped and in its natural, unforced state. Turning operations also utilize absorbent sponges inserted into the workpiece's internal cavity to effectively prevent vibration during machining of outer diameters and inner holes. This method is simple, convenient, uses readily available materials, and is economical.

[0029] This invention provides an economical and convenient solution to the vibration prevention problem during milling and turning operations, and can be applied in the processing of similar thin-walled structures and weakly rigid materials.

[0030] This invention employs a low-stress clamping method, which can effectively solve the problem of clamping deformation, reduce the gap between on-machine measurement and measurement under stress for easily deformable parts, and effectively ensure the machining accuracy of thin-walled parts.

[0031] In this embodiment, a sponge is inserted into the inner cavity of the workpiece.

[0032] In this embodiment, the workpiece is loaded into a sleeve clamp, the outer circle of the workpiece is fitted with the sleeve with a small clearance, the workpiece is clamped by friction, and then the workpiece is evenly wrapped on the clamp by tape.

[0033] In this embodiment, a low-stress clamping method is adopted, which ensures that the workpiece is clamped under uniform force and that the machining part is processed in a stress-free state.

[0034] This invention combines the material, structure, and dimensional accuracy characteristics of the cabin to solve the problems of easy vibration during milling, easy deformation and vibration during precision machining of turning, and ensures the machining accuracy of the workpiece.

[0035] To address the vibration phenomenon, floating reinforcement can be added to the middle section of the compartment as follows: Figure 4 As shown, after the workpiece is aligned, clamped and fixed, a rubber sleeve with a certain elasticity is used at the upper end of the workpiece near the machining part. The rubber sleeve has elastic pre-tightening force, which strengthens the rigidity of the workpiece when milling the inner cavity and machining the opening groove, and at the same time plays a role in damping vibration.

[0036] Analyzing the workpiece structure and machining methods, and addressing the out-of-roundness issue of the two holes during finish turning, three approaches were taken: first, changing the clamping method to reduce the impact of workpiece deformation during clamping; second, improving the accuracy of the reference machining to reduce the problem of deformation replication. The finish turning of the outer diameter was changed from the original top-mounted clamping to using a mandrel to engage with the workpiece's inner hole, pressing against the cavity step (as shown below). Figure 5 , 6As shown), the outer diameter, end face, and inner hole φ150+0.08+0.03 are processed in one operation, reducing one clamping operation on the workpiece. The step clamping within the cavity results in a smaller workpiece length-to-diameter ratio and less clamping deformation compared to pressing the entire workpiece. A sponge is then inserted into the workpiece cavity (as shown below). Figure 7 As shown in the figure, this process plays a role in shock absorption. This process effectively improves the machining accuracy of the φ150+0.08+0.03 inner hole and the machining accuracy of the outer circle, thus effectively improving the datum accuracy.

[0037] The second finishing process involves placing the workpiece into a sleeve clamp, ensuring a small clearance fit between the workpiece's outer diameter and the sleeve. The workpiece is then clamped using friction, and finally, tape is used to evenly wrap the workpiece around the clamp (as shown below). Figure 8 As shown), the workpiece is repeatedly cut to size with a small allowance. A low-stress clamping method is used, which ensures that the workpiece is clamped with uniform force and that the machining part is in a stress-free state. This reduces clamping deformation and the replication of the datum. The low-stress clamping method is suitable for fine turning with small cuts and low speed.

[0038] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for precision machining of a PEEK low-rigidity thin-walled cabin, characterized in that, Comprise: After the workpiece is fixed and clamped, a certain elastic rubber sleeve is used on the workpiece end near the machining part; The fine turning of the outer circle is changed from the original top clamping to the use of mandrel cooperating with the workpiece inner hole to press the cavity step; The outer circle, end face and inner hole are machined in one process.

2. The precision machining method for PEEK low-rigidity thin-walled cabins according to claim 1, characterized in that, Put the sponge into the workpiece cavity.

3. The precision machining method for PEEK low-rigidity thin-walled cabins according to claim 2, characterized in that, Put the workpiece into the sleeve chuck, the outer circle of the workpiece cooperates with the small gap of the sleeve, and the workpiece is clamped by using friction force, and then the workpiece is evenly wrapped on the chuck by using adhesive tape.

4. The method of claim 1, wherein the PEEK low-rigidity thin-walled cabin is a precision-machined part. Low stress clamping method is adopted, the workpiece clamping stress is uniform, and the machining part is in a stress-free state.

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