Discontinued Navy Ship Parts to Be Produced and Used via 3D Printing

Saenggiwon and Navy Successfully Operate 'Gearbox Main Shaft' for One and a Half Years
Maintenance Period Reduced to One-Sixth and Budget Cut to One-Twentieth Compared to Orders

[Asia Economy Reporter Kim Bong-su] A technology has been developed that urgently manufactures parts through 3D printing to enable normal operation when Navy ships, whose parts have long been discontinued, break down.

The Korea Institute of Industrial Technology (KITECH) announced on the 18th that it successfully repaired the 'reduction gear main shaft,' a core component of the powertrain of the Navy's main ships, using metal 3D printing technology, reinstalled it on the ship, and operated it normally at sea for one and a half years.

According to KITECH, while the lifespan of weapon systems such as Navy ships is usually 30 to 50 years, the lifespan of accessory parts is short, only 4 to 7 years, making periodic part replacement essential. However, as weapon systems age, more than a thousand discontinued parts exist, and the demand for small-lot, multi-variety production causes procurement difficulties. Therefore, the Ministry of National Defense is actively seeking to introduce 'metal 3D printing technology' as a new solution to resolve parts supply issues and urgently manufacture damaged parts during wartime.

The reduction gear main shaft urgently manufactured by KITECH using 3D printing plays a role in reducing the speed of the high-speed engine and controlling torque. It is a part prone to defects due to frequent vibrations and heavy loads causing aging. As a large part measuring 1.8 meters in length, new custom manufacturing takes more than six months and costs about 60 million KRW, making it very expensive. Above all, the ship with the detected defect had to remain on standby at the maintenance depot, unable to deploy until the part procurement was completed.

Dr. Sung Ji-hyun and Dr. Oh Ho-jin of KITECH’s Smart Manufacturing Technology Research Group, together with Mr. Ahn Seok from the Navy Maintenance Depot, completed the repair work in a short period in January 2020 by applying the 'DED (Directed Energy Deposition)' process, one of the metal 3D printing technologies, which stacks dissimilar materials on the defective area. The 'DED process,' similar in principle to welding, selectively irradiates a laser beam on the part surface to melt and stack metal powder. It is suitable for repairing damaged mechanical parts as it can combine various materials layer by layer.

The DED-based repair technology used this time is a system technology that integrates the 3D additive design, process optimization, and physical property evaluation technologies and know-how accumulated since the establishment of the 3D Printing Manufacturing Innovation Center in 2016. This is the first domestic case of applying it to repair large powertrain parts where quality and reliability are critical.

The repaired reduction gear main shaft has been installed on the ship and has undergone operational evaluation for one and a half years. No defects have occurred so far, proving the applicability of DED-based repair technology for aging powertrain parts. Notably, the repair period was reduced to one month, one-sixth of the custom manufacturing time, and the cost was reduced to 3 million KRW, one-twentieth of the original cost, contributing to national budget savings.

The Navy plans to complete unit operational evaluation and quality assurance review of the repaired parts within this month. The applied technology is evaluated as a useful on-site repair technology even in emergency maintenance situations that may occur during deep-sea patrols or cruising training.

Dr. Lee Ho-jin of KITECH said, “This case is a representative example showing the current status and excellent reliability of 3D printing repair technology, greatly expanding the application scope beyond the previously limited housing parts. We plan to continuously discover various additional cases targeting discontinued or procurement-challenged powertrain parts in cooperation with the Navy and the Ministry of National Defense.”

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