Machining of thin-walled parts
Thin-walled parts, defined as those with a small wall thickness-to-diameter ratio, are widely used in aerospace, automotive, precision instrumentation, and other fields. Due to their structural characteristics, thin-walled parts are prone to deformation during turning, affecting the dimensional and shape accuracy of the parts. This is a major challenge in turning thin -walled parts. Thin-walled parts have poor rigidity and are susceptible to bending, vibration, and deformation under the influence of cutting forces, clamping forces, and cutting heat, resulting in substandard part quality. Therefore, controlling deformation during turning of thin-walled parts is key to improving their machining quality.
To reduce deformation during the turning process of thin-walled parts, it is necessary to rationally select cutting parameters. Cutting speed, feed rate, and cutting depth are the main factors affecting cutting forces and cutting heat. When turning thin-walled parts, a higher cutting speed should be used to reduce the generation of cutting forces and cutting heat. A higher cutting speed allows the cutting edge to quickly cut into the workpiece, reducing the contact time between the tool and the workpiece, thereby reducing the impact of cutting forces and cutting heat on thin-walled parts. At the same time, a smaller feed rate and cutting depth should be selected to avoid deformation of thin-walled parts caused by excessive cutting forces. The selection of feed rate and cutting depth should be reasonably adjusted according to the material, wall thickness, and processing requirements of the thin-walled part, minimizing deformation while ensuring processing efficiency.
The choice of cutting tool also has a significant impact on the turning quality of thin-walled parts. Sharp, wear-resistant, and heat-dissipating cutting tools should be selected to reduce cutting forces and heat. The tool’s geometric parameters should be rationally designed based on the material of the thin-walled part and the processing requirements. For example, the tool’s rake and clearance angles should be appropriately increased to reduce friction between the tool and the workpiece, thereby lowering cutting forces. At the same time, the tool’s tip radius should be small to minimize extrusion and friction during cutting and avoid plastic deformation of thin-walled parts. Furthermore, the tool’s material should also be selected based on the material of the thin-walled part. For thin-walled parts made of difficult-to-machine materials such as stainless steel and high-temperature alloys, carbide or ceramic cutting tools should be selected to improve the tool’s wear resistance and cutting efficiency.
The choice of clamping method is crucial for controlling deformation during turning of thin-walled parts. Traditional three-jaw chuck clamping can easily cause radial deformation in thin-walled parts. Therefore, a suitable clamping method should be employed when turning thin-walled parts. For example, axial clamping can be used to clamp the workpiece through end-face positioning, reducing the impact of radial clamping force on thin-walled parts. Alternatively, specialized fixtures, such as soft jaws or fan-shaped jaws, can be used to increase the clamping area and evenly distribute the clamping force, preventing deformation caused by excessive localized force on thin-walled parts. Furthermore, the clamping force should be controlled during the clamping process to avoid deformation of thin-walled parts caused by excessive clamping. The appropriate clamping force can be determined through trial cutting or the use of a force measuring device.
The use of cutting fluid can effectively lower cutting temperatures, reduce tool wear, improve workpiece surface quality, and play a positive role in controlling deformation during turning of thin-walled parts. When turning thin-walled parts, it is important to select an appropriate cutting fluid, such as an emulsion or cutting oil, and ensure an adequate supply of the fluid. Cutting fluid can reduce friction and heat generation during the cutting process through cooling, lubricating, and cleaning effects, thereby reducing thermal deformation of thin-walled parts. It also washes away chips, preventing friction and compression between the chips and the workpiece surface, and protecting the workpiece surface quality. When using cutting fluid, pay attention to its concentration and temperature, and replace it regularly to ensure its performance. Furthermore, advanced cooling methods such as spray cooling can be used to improve cooling efficiency and further reduce deformation of thin-walled parts.
