Factors affecting machining of thin-walled parts
- 1. The workpiece is thin-walled and easy to deform under the action of clamping force, which affects the dimensional accuracy and shape of the workpiece.
- 2. The cutting heat generated in machining causes the thermal deformation of thin-walled parts and affects the dimensional accuracy.
- 3. Under the action of cutting back force, it is easy to produce vibration and deformation, affecting the dimensional accuracy, surface roughness and shape and position accuracy of the workpiece.
Method for reducing deformation of thin wall workpiece
- 1. Rough and fine turning and sequential machining are adopted: in rough turning, the corresponding clamping force is slightly larger in consideration of large cutting allowance and improving machining efficiency. Before finishing turning, properly release the claw to eliminate the deformation caused by excessive cutting force during rough turning. During finishing turning, the clamping force can be slightly smaller and the processing is completed.
- 2. Geometric parameters of cutting tool: the reasonable selection of cutting tool parameters is an important symbol to reflect the comprehensive effect of multiple factors in the cutting process. The cutting angle and the shape of the cutting edge affect each other in cutting, focusing on maintaining the sharpness of the blade and the stability of the cutting process, so as to reduce the cutting force. A larger rake angle and a smaller tip angle should be selected. From the aspect of reducing vibration, we should use a smaller tool back angle to increase the contact area between the back of the tool and the workpiece, so as to achieve the purpose of vibration elimination.
- 3. When finishing turning thin-walled workpieces, the rigidity of the tool handle shall be high, the polishing edge of the turning tool shall not be too long (generally 0.15mm-0.3mm), and the edge shall be sharp.
- 4. Selection of cutting parameters: the cutting force is closely related to the back draft, cutting speed and feed rate. When the back draft and feed rate increase at the same time, the cutting force will be large and the workpiece deformation will be large; Reduce the back draft and increase the feed rate (0.6-0.8mm / R). Although the cutting force decreases, the surface residual area of the workpiece is large and the roughness increases, resulting in part deformation. Generally, during rough machining, the back feed and feed can be larger. During finish machining, the back feed should be about 0.3-0.5mm, and the feed should be about 0.15mm/min. During finish turning, high cutting speed should be selected. The three should be appropriate to improve the machining accuracy.
- 5. Selection of clamping process: use slotted sleeve or special soft claw to increase the contact area during clamping and make the clamping force evenly distributed on the thin-walled workpiece, so as to reduce the deformation caused by clamping. Pouring sufficient cutting fluid during cutting is an effective method to prevent and reduce the deformation of thin-walled workpiece.
The above processing methods are often encountered in production practice, and there are inevitable mistakes in the above discussion. Please forgive and correct.