Coating under high voltage

A manufacturer of high-voltage equipment converted its coating of 12-meter aluminum tubes to HDLV technology. As a result, he was able to improve surface quality and double his production capacity.

Hitachi Energy is one of the world's leading manufacturers of high-voltage equipment and produces some of the components required for this in Brno. In the Czech Republic's second largest city, the company coats aluminum tubes up to twelve meters long, which have different geometries inside and a diameter of up to 0.80 meters. Hitachi Energy uses an environmentally friendly powder coating process for this purpose. The plant manufacturer wanted to double production capacity, but without compromising on the high safety and quality standards of the coating process. These apply because of the high-risk application area.

Increasing output with the automatic guns of the existing old plant was not possible to the desired extent. In addition, Hitachi also wanted to make the coating process more economical and achieve powder savings in order to meet the company's high environmental requirements. On this basis, the company management decided to invest in a new, robot-guided powder plant.

High-quality edge and corner coatings

As part of their research, Hitachi Energy executives learned about HDLV dense phase technology and conducted some preliminary testing at a ventilation equipment manufacturer. "Although we did not have 3D models of the workpieces for this robotic coating and therefore could not program the robots accurately, our customer was impressed with the results," says Jaroslav Blažek, managing director at Czech systems integrator Surfin Technology.

In order to put the technology through its paces on the workpieces in its own production, Hitachi Energy then received two Encore HD manual coating systems from HDLV supplier Nordson. The associated powder guns are lightweight and well-balanced, and enable high-quality, fast coatings that can be repeated at any time, regardless of the powder. They also feature good edge and corner coatings, as well as optimal penetration depth, even into complicated geometries. "We were extremely positively surprised by the performance of Nordson HDLV technology. We did not expect the result like this," Vaclav Holecek, Production Development Specialist and Corrosion Engineer at Hitachi Energy, reports in retrospect.

Based on the good results, the company decided to use this technology and contracted Surfin Technology to install two Nordson ColorMax E powder coating systems with robotic coating guns.

In the final plant setup, the inside surfaces of the pipes in booth 1 are now coated with two Encore HD powder guns mounted to two ABB robotic coating systems. The dense phase guns provide repeatable, reproducible coating quality, realize low powder consumption and combine flexibility and profitability in powder coating. The Spectrum HD powder center ensures reliable powder supply. The integrated dense phase pump technology ensures precise powder feed and combines consistent coating results with significant powder savings with minimal maintenance and downtime.

Precise control of the powder center is provided by Nordson's PowderPilot HD control system. It allows the operator to adjust all aspects of high-quality powder application - from conveying and atomizing air to electrostatics, gun stroke and triggering - via the simple and colorful touch-screen control.

15 color changes per day

Since Hitachi Energy manufactures the high-voltage equipment for customers all over the world, the components are coated in different colors. For powder coating, this means up to 15 color changes per day. To implement these quickly and reliably, Hitachi Energy also chose Nordson's automated Color-on-Demand (CoD) system. It offers "color on demand" and implements color changes in 20 to 50 seconds. The system automatically cleans the entire supply line - from the powder hopper to the powder gun. Manual color changing is not necessary.

Another advantage of the system is that users can implement customer requests quickly and reliably, even for batch size 1 and small batches.Hitachi Energy uses the CoD system in booth 1, with the company powdering at a loss in order to be able to perform the fast color changes in a few seconds. "This is very efficient precisely because of Nordson dense phase technology, as the extremely soft dense phase powder cloud allows the robotic guns to get very close to the workpieces with no bounceback effect and minimal overspray," explains Nordson sales manager Martin Vodak.

The outer surfaces of the aluminum tubes are powdered in booth 2, which, like booth 1, has Encore HD robotic guns and two painting robots. It is also equipped with a twin cyclone, as this is where the overspray is processed and fed back into the production cycle. Special features of the plant include load cells on the Spectrum HD powder centers, on the Color-on-Demand systems, and on the two final filters. With a view to the high standards of environmental compatibility and sustainability, they inform the user about the current powder consumption and the amount of overspray.

Production capacity doubled

Installation and commissioning of the new powder coating system was implemented by Surfin Technology, together with Nordson's 2021 service technicians, during the Christmas period, allowing the plant to start operating immediately after the production break. "By combining robots and Nordson dense phase technology, we have doubled our production capacity, even though we are powder coating with fewer guns than before," Vaclav Holecek summarizes the experience with the new powder coating system. "We have achieved high process repeatability for our process, and the system now allows us to plan production and monitor the production process more efficiently. At the same time, the manual work and rework previously required has been reduced to almost zero.

From time to time, for example with special workpieces, we still work with manual coating. For this purpose, we also have our own station with a hand booth and an Encore HD dolly in production," explains Holecek. "Thanks to the soft cloud provided by HDLV technology, the same high-quality result is always achieved. With employees in mind, high operator safety is ensured at the same time, as well as maximum material utilization and a significant reduction in powder consumption."

With the coated products, the manufacturer of high-voltage equipment is now able to meet the strict requirements of safety standards and to reliably reproduce the coating processes of the different products at any time. He can also efficiently plan his production and monitor the processes. By reducing powder consumption and maximizing the utilization of the material, he also meets the company's own environmental goals.

Nordson Germany GmbH

www.nordson.com