Machining Method For High-precision Thin-walled Parts Of Titanium Alloy

The shapes of thin-walled parts that are common in daily life are generally ring-shaped, shell-shaped, and flat-plate-shaped. The structural size of these parts is generally much larger than its thickness. When the ratio of its structural size or curvature radius to its own thickness is greater than 20, we call it a thin-walled part. Thin-walled parts can be divided according to the most basic material properties. Generally, there are titanium alloys, plastics and some composite materials. The thin-walled parts processed by these different materials have different properties and can meet the needs of various markets. This paper mainly analyzes the high-precision processing methods of titanium alloy thin-walled parts. Thin-walled parts are almost always composed of thin plates and ribs, which is why thin-walled parts are light in weight. By manufacturing thin-walled parts of different specifications, they can be applied to various purposes. According to the structural use, thin-walled parts can be divided into beams, joints, wall panels, and ribs. These different types of parts have their own unique shapes and complete their respective functions. However, the characteristics of this thin-walled part make the production process more difficult, because the thin-walled part has low rigidity, so it is easy to deform during the processing process, resulting in the production of thin-walled parts that do not meet the standards. From this, it can be seen that the analysis of the processing method of thin-walled parts and the optimization of its processing technology are very necessary, and it is of great significance to promote the development of the thin-walled parts processing industry.

1. Influence of clamping factors on part deformation

The clamping process is one of the core processes of the entire thin-walled parts processing technology. No matter what processing method is used, the quality of the clamping process will directly determine the processing quality of the thin-walled parts. For the processing of thin-walled parts, the clamping scheme, clamping point position and clamping force determine the quality of the processed parts. If an inappropriate clamping point position or clamping force is used, it may cause different degrees of deformation of the part, and it will also greatly affect the machining accuracy of the part. Especially when processing thin-walled parts on the machine tool, the importance of the clamping process is fully reflected. Among them, 30% to 50% of the machining errors come from the clamping process. In addition, during the processing of thin-walled parts, the fluctuation effect between the tightening force and the cutting force will produce a coupling effect, which will lead to the redistribution of machining residual stress and initial residual stress inside the part, which will also affect the processing quality of the part. Therefore, the clamping problem of thin-walled parts still cannot be ignored. Improving the clamping process of thin-walled parts is of great significance to prevent the deformation of parts during processing.

2. Influence of cutting force and cutting heat on part deformation

The processing parameters of thin-walled parts directly reflect the relationship between thin-walled parts and processing tools. During the processing of thin-walled parts, due to the low elastic modulus of titanium alloy thin-walled parts, the surface of the processed part will have a large springback, which will directly lead to an increase in the contact area between the processed surface and the flank of the tool, which will have a great impact on the processing quality of the thin-walled part, causing the machining accuracy of the part to drop sharply. At the same time, it will also reduce the durability of the tool. On the other hand, if the cutting force is too large, exceeding the elastic limit of the material, it will cause plastic deformation of the part. Moreover, the existence of cutting heat is also one of the keys that affect the processing quality of parts. Cutting heat is generated by the friction between chips and rake face, the machined surface of the workpiece and the flank face. A large amount of cutting heat will lead to uneven temperature of various parts of the workpiece, and will also aggravate the deformation of the parts, resulting in a decrease in the machining accuracy of the parts. At the same time, the surface quality of the parts cannot be well guaranteed.

3. Influence of residual stress on deformation

Residual stress in thin-walled parts has two main components. Part of it is the initial residual stress generated during the initial forming process of thin-walled parts. There are many reasons for the generation of this part of residual stress. Among them, for large-area spliced composite thin-walled parts, the influence of residual stress during processing is more obvious. The second part is the residual stress of the machined surface. This part of the residual stress is mainly the result of the comprehensive influence of various factors such as the mechanical action of the tool on the surface metal of the workpiece, the thermal action, and the elastic recovery of the inner metal. During the processing of thin-walled parts, it is very likely to break the balance of residual stress in the part blank. At this time, the stress balance inside the part is broken, resulting in stress redistribution, which causes the deformation of the part.

In general, there are many factors that lead to the deformation of thin-walled parts during processing, and these factors are primary and secondary. How to distinguish the key influencing factors and effectively control them, and optimize and improve the processing technology of thin-walled parts is an effective means to control the processing deformation of thin-walled parts. This paper analyzes the reasons for the processing deformation of thin-walled parts, and summarizes the current control methods for processing deformation of thin-walled parts. It can be seen that by changing the traditional processing method and optimizing the processing technology, it is helpful to the processing of the workpiece, which can reduce the deformation of the workpiece to a certain extent, and ensure the stability and usability of the produced product. However, only by comprehensively considering all the influencing factors, by means of finite element analysis and numerical simulation, the deformation of thin-walled parts can be further predicted and controlled, in order to improve the processing quality of thin-walled parts.