Difficult-to-Handle 'Titanium' Easily Processed with 3D Printing

-Korea Institute of Industrial Technology Develops 'Metal 3D Printing Technology' Using Arc and Wire
-Composite System Enables Production of Large Parts 5 Times Faster Than Powder Materials

[Asia Economy Reporter Kim Bong-su] A technology has been developed that processes titanium?which is hard and light but difficult to machine and does not rust?into various parts using 3D printing.

The Korea Institute of Industrial Technology announced on the 8th that it has developed a metal 3D printing technology using electric sparks called ‘Arc’ and wire, achieving optimization of the manufacturing process for titanium parts, which are known to be difficult to machine.

Titanium parts have the strength comparable to steel but weigh about half as much, do not rust, and have excellent heat resistance. They are gaining attention as next-generation material for parts in aerospace, energy, plant, and defense industries.

The problem is that titanium is considered a representative hard-to-machine material, making it difficult to process, and it oxidizes at high temperatures, making welding challenging. Recently, metal 3D printing has emerged as an alternative processing method, but it has issues such as high costs for powder materials and heat sources, and low productivity with only about 900g layered per hour.

Dr. Kang Dong-hyuk’s research team at the Joining and Additive Manufacturing Division of the Korea Institute of Industrial Technology developed next-generation metal 3D printing technology that uses arc as the heat source instead of the conventional laser and replaces powder materials with wire to solve these problems. The arc heat source used in this technology costs about one-tenth of laser equipment, making the setup cost very low and advantageous for manufacturing large parts. Since wire is melted and layered instead of powder, the material cost is reduced by about 80%, material waste is cut by 65%, and the layering speed is improved by about five times.

This technology generally uses direct current (DC) power and stacks materials at an angle different from the heat source when layering common metal materials, but for titanium parts, this caused quality degradation and difficulties in system automation. Titanium has a unique property of emitting thermoelectrons, so using DC to melt the wire generates unstable plasma. In this case, heat is not properly transferred, causing the material to splash around or stack unevenly, creating bubbles that lead to defects.

The research team independently developed a short-circuit transition technology based on alternating current (AC) power, where size and direction periodically change over time, and a helium gas environment process, solving the titanium parts processing issues. Using the AC power-based short-circuit transition technology allows polarity switching of the arc while lowering voltage and reducing current. When the heat source and wire are aligned on the same axis and the material is melted, it is possible to stack cleanly and uniformly without splashing. Additionally, they developed a processing method that creates a helium gas environment to prevent titanium oxidation, which does not generate unstable plasma, thereby improving productivity and quality.

Furthermore, to overcome another drawback of the arc wire layering method, which makes it difficult to precisely manufacture complex-shaped products, a composite system that integrates layering, post-processing, and diagnostics is under development. This system includes layering monitoring and artificial intelligence quality prediction technology, enabling real-time control of process variables such as temperature and shape, allowing high-quality production of complex shapes.

Dr. Kang said, “This is a core technology that can realize high-speed, high-quality, and large-area metal 3D printing systems,” adding, “Starting with lightweight defense parts where titanium demand is high, we plan to expand applications to energy and chemical plants and eventually to the aerospace industry.”

This content was produced with the assistance of AI translation services.