The combination of titanium alloy and 3D printing has become a new trend in industrial development. Due to the small thermal conductivity of titanium alloy, the local rapid heating in the cutting process and the heat is difficult to release, so the processing method of reducing material manufacturing is difficult, and the 3D printing process of additive manufacturing better avoids the drawbacks of the traditional way, and the combination of the two is expected to become a new trend. For example, foreign watch manufacturer Barrelhand and head 3D printing equipment supplier Materialise cooperate to use 3D printing process to produce titanium alloy watch case, Honor released a new folding screen mobile phone Magic V2 in the folding screen hinge hinge part of the titanium alloy 3D printing process. It has become the world's first folding flagship machine with titanium alloy hinges, and it is also the first large-scale use of 3D printing titanium alloy process on mobile phones.
Why use 3D printing to make titanium alloy structural parts?
(1) Traditional machining of titanium alloys is difficult. Compared with stainless steel and aluminum alloy, traditional machining has a certain difficulty in the face of titanium alloy. This is mainly because the thermal conductivity of titanium alloy is low, and the thermal conductivity of common TC4 titanium alloy is only 7.96W/m·K, which is far lower than that of stainless steel and aluminum alloy. This leads to titanium alloy heat accumulation in processing, local heating fast. According to the data of Advanced Manufacturing technology network, the traditional cutting method can make the local temperature of titanium alloy more than 1000℃, on the one hand, lead to the tool edge wear, cracking and debris accumulation, shorten the tool life, on the other hand, the local high temperature also destroyed the surface integrity of titanium alloy, resulting in a decrease in accuracy and reduce its fatigue strength. According to Ai Bang polymer data, the overall yield of the mobile phone frame using titanium alloy material is about 30%-40%, which is far lower than 80% of the aluminum alloy frame. Traditional machining of other metals has been relatively mature. The price of stainless steel and aluminum alloy is cheaper than titanium alloy, while the thermal conductivity of stainless steel and aluminum alloy is higher, and there will be no problems similar to titanium alloy processing when using the traditional material reduction process, so the processing process through CNC or die casting has been very mature, raw material prices and processing costs are low. In the short term, the cost performance advantage of using 3D printing process is insufficient.
(2) The technical process of 3D printing is well adapted to the preparation of titanium alloy parts. a, metal 3D printing represented by SLM technology is different from traditional CNC plate and bar reduction manufacturing, SLM is an additive manufacturing process through the laser melting of metal powder and layer upon layer accumulation, which avoids the drawbacks of cutting titanium alloy from the technical route; b, the additive manufacturing layer printing process has low cost sensitivity to complex structures, so the design freedom during processing is high, and lightweight can be achieved through more internal cavity structures; c, 3D printing equipment through large size design and equipped with more laser heads, can achieve multiple forming at a time, printing efficiency is significantly improved; d, 3D printing is an integrated forming technology, compared with cutting processing, its output structural parts have better strength and consistency.
(3) 3D printing titanium alloy process significantly improves the performance of foldable screen mobile phones. In July 2023, Glory released a new folding screen mobile phone Magic V2, which uses titanium alloy material in the hinge of the key parts at the folding place. The main role of the hinge is to assist the folding of the flexible screen, which plays an important role in the durability of the mobile phone, the fit degree of the folding state and the flatness of the expansion state. According to Honor official data, thanks to the application of titanium alloy hinges, the folding thickness of Magic V2 is as low as 9.9mm, the expansion thickness is only 4.7mm, the strength of aluminum alloy material is increased by 150%, more than 400,000 folds can be achieved, the weight is only 231g, and the performance indicators lead the majority of folding screen mobile phones on the market.
What is the relationship between 3D printing and CNC and MIM processes?
The relationship between 3D printing and CNC is complementary and substitutive
(1) Structural end 3D printing can partially replace CNC machining. Because 3D printing has a low cost sensitivity to complex structural parts, the method of additive manufacturing determines that it is suitable for processing more complex structural parts, so when the workpiece involves a curved shape and has more hollow structures inside, 3D printing can replace the CNC process. In addition, 3D printing has high customization characteristics, so it has a broad application prospect in medical orthopedic implants. (2) Material side 3D printing is complementary to CNC machining. For titanium alloy, superalloy and other difficult to process materials, additive manufacturing through layer laying powder processing accumulation forming, from the technical principle to avoid the traditional machining in the cutting process easy to produce drawbacks. Therefore, 3D printing can help CNC complete the molding process of more difficult processing materials, while the processed blank also needs subsequent annealing, wire cutting and polishing and polishing links, CNC grinding and polishing machine tools in the post-processing link will be a step further fine processing, the two processes can complement each other. (3) The complementarity and substitution of the two processes coexist, and economy is an important consideration in the selection. Taking the processing of titanium alloy materials as an example, the advantages of 3D printing are high utilization of raw materials, high yield, and support for complex structures, while the advantages of CNC are that the printing size is large, the structural complexity is moderate, and the cost of a single product is low when large-scale production.
