Method for machining thin-walled sleeves

Abstract

The present application relates to the technical field of machining, and discloses a thin-walled sleeve machining method, characterized by comprising the following steps: S1, a pre-grinding process state, the tubular blank comprising a process clamping section and a product forming section; S2, clamping and fixing the tubular blank through the process clamping section by using an internal grinding machine, coarsely grinding and finely grinding the inner hole of the product forming section, so that the inner hole reaches the design size; and S3, separating the process clamping section from the product forming section, clamping the product forming section on an external grinding machine by using a mandrel, and finely grinding the external circle to the design size; the process scheme of the present application does not need to customize high-cost special tooling such as a fan-shaped soft jaw, a damping vibration reduction device or an elastic mandrel, thereby solving the problem that the machining method in the prior art cannot guarantee the thin-walled machining precision due to the high cost of the special fixture.

Description

Technical Field

[0001] This invention relates to the field of machining technology, and in particular to a method for machining thin-walled sleeves. Background Technology

[0002] Thin-walled sleeve parts, as key basic components in mechanical transmission systems, are widely used in aerospace, precision instruments, hydraulic systems, and other fields. These parts typically have a wall thickness to diameter ratio of less than 1:10. Due to their poor rigidity and low bending modulus, they are highly susceptible to elastic deformation and vibration during machining due to the combined effects of cutting forces, clamping forces, and thermal deformation, making it difficult to control machining accuracy. Even with high-precision internal grinding machines, traditional machining processes still face fundamental challenges: when clamping a single part, the clamping force inevitably causes deformation of the thin wall, resulting in a roundness error of generally 0.02-0.05mm after internal hole grinding, which is difficult to achieve the 0.005-0.01mm accuracy level required by precision equipment.

[0003] In existing machining technologies, deformation control for thin-walled parts mainly relies on tooling improvements. While fan-shaped soft jaws can disperse clamping stress, they require custom-made jaws, resulting in long tooling preparation cycles and poor economic efficiency for single-piece, small-batch production. Damping vibration reduction processes fill the workpiece and fixture with polymer materials, but due to differences in the thermal expansion coefficients of these materials, additional deformation occurs under cutting heat, and process parameter adaptation is complex. Axial clamping with a nut pair avoids radial deformation, but increases the workpiece overhang, exacerbating machining vibration, and is also cumbersome and inefficient. Specialized fixtures such as elastic expansion mandrels and vacuum adsorption devices can improve accuracy, but their high investment costs—ranging from 80,000 to 120,000 yuan per system—make them difficult to promote in multi-variety, small-batch production.

[0004] The key issue is that existing processes fail to fundamentally resolve the contradiction between clamping deformation and machining accuracy. During traditional internal grinding, regardless of the fixture used, a single thin-walled sleeve will inevitably undergo elastic deformation under radial clamping force. While the grinding process may appear to achieve the required accuracy, elastic recovery after unloading leads to dimensional deviations. More seriously, after machining the inner hole, the outer diameter needs to be re-clamped for grinding, further accumulating secondary positioning errors and making it difficult to guarantee coaxiality. In industry practice, over 65% of manufacturing enterprises, despite being equipped with precision internal grinding machines, are still unable to stably produce high-precision thin-walled kits, forcing them to resort to remedial measures such as group selection or manual grinding, severely restricting production efficiency and product quality.

[0005] Therefore, it is urgent to break through the traditional single-piece processing mode and develop a solution through process innovation rather than equipment upgrade. Based on ordinary internal grinding machines, by optimizing the processing flow and clamping strategy, the impact of clamping deformation on accuracy can be fundamentally eliminated, so as to achieve high-precision, low-cost and high-efficiency thin-walled sleeve processing. Summary of the Invention

[0006] The purpose of this invention is to provide a method for machining thin-walled sleeves, which solves the problem that existing machining methods cannot guarantee the machining accuracy of thin-walled sleeves due to the high cost of special fixtures.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, the present invention discloses a method for processing thin-walled sleeves, comprising the following steps: S1. Pre-grinding process state, the tubular blank includes a process clamping section and a product forming section; S2. Using an internal cylindrical grinding machine, the tubular blank is clamped and fixed in the process clamping section to perform rough grinding and fine grinding on the inner hole of the product forming section, so that the inner hole reaches the design size; S3. Separate the process clamping section from the product forming section. Clamp the product forming section on the external cylindrical grinding machine with a mandrel and finely grind the outer diameter to the design dimensions.

[0008] As an optional solution, in step S1, the length of the clamping section is 20-30mm and the wall thickness is 4-5mm.

[0009] As an optional solution, in step S1, the outer circle of the product forming section is reserved with a machining allowance of 0.8mm-0.9mm, and the inner hole is reserved with a machining allowance of 0.2mm-0.3mm.

[0010] As an optional solution, in step S1, after rough grinding the inner hole of the product forming section, a machining allowance of 0.08-0.1mm is reserved in the inner hole of the product forming section.

[0011] As an optional option, in step S2, before the tubular blank is processed by the internal grinding machine, the process clamping section and the product forming section of the tubular blank are turned by a lathe.

[0012] As an optional solution, in step S2, after rough grinding the inner hole of the product forming section, the tubular blank is removed and subjected to aging treatment.

[0013] As an optional solution, in step S1, the product forming section includes multiple continuously arranged part forming units, and the outer circular surface between adjacent part forming units is provided with circumferential partition grooves.

[0014] As an alternative, wire cutting is used to separate the blank by cutting along the circumferential dividing groove on the outer circle, cutting the blank into individual parts of the required length.

[0015] The present invention has the following unexpected beneficial effects: The thin-walled sleeve machining method provided by this invention divides the tubular blank into a process clamping section and a product forming section. This allows an internal cylindrical grinding machine to clamp the blank through the process clamping section and perform rough and fine grinding on the inner hole of the product forming section. The process clamping section and product forming section are then separated, and a mandrel is used to clamp the product forming section onto an external cylindrical grinding machine for fine grinding. This method effectively avoids the reliance on expensive specialized fixtures in traditional processes. Through process optimization and innovative clamping methods, it significantly improves machining accuracy and efficiency. This process eliminates the need for customized fan-shaped soft jaws, damping vibration reduction devices, or elastic mandrels, which are high-cost specialized tooling. This solves the problem in existing technologies where high-cost specialized fixtures cannot guarantee the machining accuracy of thin-walled sleeves. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart of the processing method for the thin-walled sleeve structure provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the parts according to an embodiment of the present invention; Figure 3 This is a cross-sectional view of a part according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the blank in an embodiment of the present invention; In the diagram, 1 represents the part; 2 represents the blank. Detailed Implementation

[0017] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0018] In the field of machining, the processing of thin-walled sleeve parts has always faced problems such as high tooling and fixture costs and insufficient process flexibility. This invention provides a method for machining thin-walled sleeves, solving the above problems by optimizing the machining process. The following is in conjunction with the appendix... Figures 1 to 3 This invention describes in detail the specific implementation of a processing method for a thin-walled sleeve part 1 structure.

[0019] In one embodiment, such as Figures 1 to 3 As shown, in a first aspect, the present invention provides a method for processing thin-walled sleeves, comprising the following steps: S1. Pre-grinding process state, the tubular blank includes a process clamping section and a product forming section.

[0020] Specifically, the length of the process clamping section is 20-30mm, and the wall thickness is 4-5mm; the outer circle of the product forming section has a machining allowance of 0.8mm-0.9mm, and the inner hole has a machining allowance of 0.2mm-0.3mm; after rough grinding of the inner hole of the product forming section, the inner hole of the product forming section has a machining allowance of 0.08-0.1mm; and the product forming section includes multiple continuously arranged part forming units, and the outer circle surface between adjacent part forming units is provided with an circumferential separating groove for the processing worker to observe and distinguish the separation position. The size of the circumferential separating groove is Φ28.2mm×3mm, the diameter of the outer circle of the product forming section before machining is Φ29.2mm, and the diameter of the inner hole of the product forming section before machining is Φ25.9mm.

[0021] S2. The tubular blank is clamped and fixed by the process clamping section of the internal cylindrical grinding machine, and the inner hole of the product forming section is rough and fine ground to make the inner hole reach the design size.

[0022] Specifically, when the machining allowance of the tubular blank is excessive, a lathe is first used to rough machine the process clamping section and product forming section of the tubular blank to remove some of the machining allowance. No further restrictions are placed on the lathe used here; the lathe used in step S2 is a common lathe such as a horizontal lathe, CNC lathe, or vertical lathe, requiring no additional design. After lathe machining, the tubular blank is more easily rough ground by an internal grinding machine. If the design requires the part to have deformation and hardness requirements, the blank can be quenched, tempered, and aged before rough grinding. In this case, the hardness of the machined part blank is between HRC45 and HRC50, and the deformation of the part blank will be controlled within 0.25mm. A standard internal grinding machine of model M2110 is used to rough grind the inner hole of the product forming section, resulting in a size of Φ26.08mm-Φ26.10mm after rough grinding. And after rough grinding the inner hole of the product forming section...

[0023] S3. Separate the process clamping section from the product forming section. Clamp the product forming section on the external cylindrical grinding machine with a mandrel and finely grind the outer diameter to the design dimensions.

[0024] Specifically, an M2110 ordinary internal grinding machine is used to grind the inner hole of the product forming section again to achieve the purpose of finishing. The inner hole of the product forming section after finishing grinding is Φ26.2mm, and the cylindricity of the inner hole of the product forming section is not greater than 0.008mm. The outer diameter of the product forming section after finishing grinding is Φ28.0mm. The taper ratio of the mandrel is 1:3000. For the process clamping section and the product forming section, wire cutting can be used to divide the blank into multiple part forming units that meet the design requirements, and the length of any product forming section is 15mm.

[0025] The thin-walled sleeve processed by this technology is machined using only a conventional lathe throughout the entire process, significantly reducing the need for high-precision equipment. The allowances for the outer edges and inner diameters of the parts are all ground using a conventional lathe, eliminating the need for customized, costly specialized tooling such as fan-shaped soft jaws, damping vibration reduction devices, or elastic mandrels. The parameters in this embodiment are preferred examples; those skilled in the art can make adaptive adjustments within the scope of the claims, taking into account material properties and equipment conditions.

Claims

1. A method for processing thin-walled sleeves, characterized in that, Includes the following steps: S1. Pre-grinding process state, the tubular blank includes a process clamping section and a product forming section; S2. Using an internal cylindrical grinding machine, the tubular blank is clamped and fixed in the process clamping section to perform rough grinding and fine grinding on the inner hole of the product forming section, so that the inner hole reaches the design size; S3. Separate the process clamping section from the product forming section. Clamp the product forming section on the external cylindrical grinding machine with a mandrel and finely grind the outer diameter to the design dimensions.

2. The thin-walled sleeve processing method according to claim 1, characterized in that: In step S1, the length of the clamping section is 20-30mm and the wall thickness is 4-5mm.

3. The thin-walled sleeve processing method according to claim 1, characterized in that: In step S1, the outer circle of the product forming section has a machining allowance of 0.8mm-0.9mm, and the inner hole has a machining allowance of 0.2mm-0.3mm.

4. The thin-walled sleeve processing method according to claim 3, characterized in that: In step S1, after rough grinding of the inner hole of the product forming section, a machining allowance of 0.08-0.1mm is reserved in the inner hole of the product forming section.

5. The thin-walled sleeve processing method according to claim 1, characterized in that: In step S2, before the tubular blank is processed by the internal grinding machine, the process clamping section and the product forming section of the tubular blank are turned by a lathe.

6. The thin-walled sleeve processing method according to claim 1, characterized in that: In step S2, after rough grinding the inner hole of the product forming section, the tubular blank is removed and aged.

7. The thin-walled sleeve processing method according to claim 1, characterized in that: In step S1, the product forming section includes multiple continuously arranged part forming units, and the outer circular surface between adjacent part forming units is provided with circumferential partition grooves.

8. The thin-walled sleeve processing method according to claim 7, characterized in that: Wire cutting separates the blank into individual parts by cutting along the circumferential dividing groove on the outer circle.

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