Titanium alloy TC4 machining secret

I. Introduction
Titanium alloy is widely used in aerospace, medical and other fields for its excellent performance. However, titanium alloys are difficult to machine, especially when machining thin-walled cavity parts, facing challenges such as chatter and deformation. In this paper, we will take a cover part made of titanium alloy TC4 material with 2mm thin-walled cavity as an example to discuss its machining difficulties and propose corresponding solutions.
Second, titanium alloy thin-walled cavity parts analysis
Titanium alloy thin-walled cavity cover parts have the following characteristics: the overall appearance of a large arc surface thin-walled cavity structure, arc surface cavity wall thickness of 2mm, the two ends of the connecting shoulder thickness of 6mm. in order to ensure that the sealing of the cover plate and the box after installation, the requirements of the cover plate parts mounting surface flatness of 0.1mm.
Third, processing technology analysis

1. Processing difficulties:
◆ Chattering problem: Due to the high hardness and poor thermal conductivity of titanium alloy material, chattering is easy to occur during the machining process, affecting the machining accuracy and surface quality.
◆Deformation problem: thin-walled structure is easy to be deformed during machining, which needs to be avoided by adopting reasonable machining process and tooling design.
2. Machining steps:
◆ Convex cavity rough milling, finish milling and mounting hole machining: firstly, process the external dimensions of the cover parts to ensure that the surface roughness meets the requirements, and process the mounting hole.
◆Concave cavity rough and finish milling processing: utilize the work tooling to realize precise positioning, adopt the method of digging grooves for rough machining, and then carry out finish machining.
◆Finishing machining of mounting surface: Ensure the flatness and surface quality of mounting surface by finishing milling, fine grinding and lapping and other machining methods.
Fourth, processing technology and tooling program design
1. Convex cavity machining:
◆ Choose four-flute end mill with high cobalt content for rough machining, keep sufficient cutting fluid to prolong tool life.
◆ Use polycrystalline cubic boron nitride ball end milling cutter for finishing, adopt streamline surface finishing method, and control the error within 0.012mm.
2. Concave cavity machining:
◆ Use workpiece to realize precise positioning of cover parts and workpiece to avoid chattering and deformation.
◆ Natural failure treatment is required after rough machining to release internal stress and prevent machining deformation.
◆ It is necessary to change the mating surface of cover part and workpiece several times during finishing machining to ensure the positioning accuracy.
3. Mounting surface finishing:
◆ Choose suitable positioning reference and mounting fixing surface, firstly carry out finish milling processing, then carry out finish grinding and lapping processing.
◆ Constant inspection is required in the process to ensure that the flatness and surface quality meet the requirements.
V. Conclusion
By analyzing and practicing the machining process of titanium alloy TC4 material, 2mm thin-walled cavity cover parts, we have successfully solved the machining problems such as chattering and deformation. Reasonable machining process and tooling design is crucial to ensure machining accuracy and surface quality. In actual machining, we should make full use of the role of tooling to reduce costs, facilitate operation, save time and high efficiency.