Coating of high-voltage equipment

Hitachi Energy is coating up to 12 m long aluminum tubes in Brno, among other high-voltage equipment. These have different geometries inside and a diameter of up to 0.80 m. A capacity doubling was needed while still ensuring that the coating of the workpieces met high safety and quality standards due to the high-risk area of application: An increase in output with the automatic guns of the existing old plant was not possible due to the requested scope. In addition, the company also wanted to make the coating process more economical and achieve powder savings in order to meet its high environmental requirements. For this reason, it was decided to invest in a new, robot-guided powder plant.Beforehand, Hitachi Energy executives took the chance to conduct some preliminary testing at an HVAC manufacturer’s facility.

„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 system integrator Surfin Technology. To put the technology to the test on the workpieces in its own production, Hitachi Energy received two “Encore HD” manual powder coating systems from Nordson. The powder guns that go with them are lightweight and well-balanced, and enable high-quality, fast coatings that can be repeatable at any time, regardless of the powder as the manufacturer states. They also feature very good coating of edges and corners, as well as optimal penetration depth, even into challenging shapes. „We were extremely positively surprised by the performance. We did not expect the result like this,“ Vaclav Holecek Production Development Specialist / Corrosion Engineer at Hitachi Energy, reports in retrospect.

Promising test results

Due to the results, the company decided to use this technology and contracted Surfin Technology to install two powder coating systems with robotic coating guns.In Booth 1, the inner surfaces of the pipes are coated with two “Encore HD” powder guns mounted on two ABB coating robots. The dense-phase guns always enable repeatable, reproducible coating quality, achieve low powder consumption, and combine flexibility and profitability in powder coating according to the manufacturer. The “Spectrum HD” powder feed center ensures a 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 feed center is provided by the “PowderPilot HD” control system. It allows the user, through the simple and color touch-screen control, to adjust all aspects for high quality powder application – from feed and atomizing air to electrostatics, gun stroke and triggering. Hitachi Energy manufactures the high-voltage equipment for customers around the world, so the components are coated in a variety of colors. For powder coating, this means up to 15 color changes per day. To be able to implement these quickly and reliably, the company selected the automatic “Color-on-Demand (CoD)” system. Color changes are done in 20 – 50 seconds. The system automatically cleans the entire powder path – from the powder hopper to the powder gun. Manual color changing is not necessary. “CoD” offers maximum flexibility and enables coatings to be applied to order at short notice. Another benefit is that users can implement customer requirements quickly and reliably, even for batch sizes of 1, and small batches.

Fast colour changes

The system in Booth 1 is used with “spraying to waste” to enable fast color changes in just a few seconds. Booth 2 is where the outer surfaces of the aluminum pipes are powdered, and like Booth 1, it features “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 returned to the production cycle. Special features include weigh cells on the “Spectrum HD” powder feed centers, on the “Color-on-Demand” systems, and on the two after filters. Regarding the high standards for environmental compatibility and sustainability, these provide the operator with real-time information about the current powder consumption and the quantity of overspray. Installation and commissioning of the new powder coating system was implemented „By combining robots and Nordson dense phase technology, we have doubled our production output, even though we are powder coating with fewer guns than before,“ says Vaclav Holecek. „

We have been able to install 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 manual booth and an “Encore HD” dolly in production. We have simply found a modern and high-quality coating solution for our products to contribute to a sustainable energy future for future generations.“

More infornation: www.nordson.com/en/divisions/industrial-coating-systems