EROWA takes the pressure off turbine blade production

At South Korean aerospace component manufacturer, Hana ITM Co, an EROWA Robot Dynamic 150L has helped the company increase its global competitiveness by reducing its non-conformities by 30% while also keeping employee numbers under tight control.

Established in 2003, Hana ITM’s impressive headquarters is located in Gimhae-si on the south-eastern coast near Busan, South Korea’s second largest city. Here, the core business is the production of aircraft and gas turbine components, and alongside chip-removing machining, the company also operates sink and wire EDM machine tools. The materials that are machined include nickel, cobalt, premium steel, and various aluminium alloys with workpiece up to a size of one metre in diameter.

Originally the company focused on honeycomb seals and shrouds for gas turbines, but then it developed a new process for the production of low-pressure turbine nozzles. CEO, Steve Yoon, played a key role in the development of the new process. As he explains: “It’s a 5-axis CBN creep-feed grinding process. The workpieces are Low-Pressure Turbine (LPT) guide vanes. Our process machines the nozzle components that are needed for this part. In contrast to classical grinding, the process has the advantage that a grinding wheel is used in which a great deal of material can be removed without burr formation, this results in larger cutting depth. Also, the process is faster, and we get a good surface quality. The grinding wheel consists of diamonds and cubic boron nitride (CBN), which is one of the hardest known abrasives. We need this, because the workpiece material is highly resistant since it has to withstand extremely high temperatures.”

It was a very difficult process to develop as Steve Yoon explains: “It was a big challenge for all of us at Hana ITM. We developed, tested and re-adapted intensively for two years… and the entire solution required substantial investment.

“Of course, there are countless ways of machining turbine nozzles, and the methods vary from company to company. The machining technology of 5-axis CBN creep-feed grinding provided the break-through for the efficient grinding of the radial grooves of turbine nozzles. We are very proud of what we have achieved, we are the only ones in Korea who are able to do this. It was also a very crucial step that the machine producer Doosan modified its DNM350 5ax with special grinding equipment for us. This machine tool is really a milling machine, but we use the machine for this creep-feed grinding process.”

Today, an automated production cell that consists of 10 of the modified Doosan DNM350 5ax are supported by an EROWA Robot Dynamic 150L. “Once stable, automating the process was the next logical step. The whole cell is 25 m long and the EROWA robot serves five machines on each side. Added to this, there are two loading stations, and after the machining process, the parts are washed and checked on a co-ordinate measuring machine,” says Steve Yoon.

He continues: “This set up has proved extremely successful. We were able to reduce personnel expenditure by 75% while reducing non-conformities by 30%. And this with a simultaneous increase in production agility. I can say that we have achieved our objective.”

The project to automate the production cell started in early 2020. However, it is not only the robots and loading stations that are from EROWA, the universal UPC workpiece tooling system that has been installed on all machine tables was also supplied by the Swiss automation specialist. Along with the JMS 4.0 process control system, which Steve Yoon states also makes a crucial contribution to success operating in the background. “It provides us with all the production data and a comprehensive overview of the workflow at all times. The washing machine and the measuring machine are also integrated in the process,” he says.

Adding: “The entire system is very agile and flexible, but with 10 creep-feed grinders working together we have the capacity to meet major orders. Our customers from the aerospace and gas turbine sector are international players, including B/E Aerospace (part of Rockwell Collins), Sukhoi Civil Aircraft of Russia, Hanwha Aerospace Korea with end customers GEAE and Pratt & Whitney, and many others. To be globally successful, you must be competent but also competitive with regard to quality, technology and cost. In addition, you must have the necessary certifications; in our case, AS9100, the international standard for quality management systems of the aviation, space and defence industries. We also have NADCAP accreditation, a standard of the aviation industry for special processes and special products; this is about the highest degree of process control.”

Hana ITM has further plans for automation in the near future. “We intend to carry automation even further,” Steve Yoon concludes. “This can be an option in a wide variety of areas, in grinding, milling, EDM and so on. At present, we are very hopeful of being awarded a new project, and that could very well be the next project for EROWA.”