Powder Coating Protects Generators HIMOINSA

Modern diesel and gas generators secure the energy supply on the open sea, in Antarctic research stations or at major events and often make the power supply of residences and industrial areas in distant regions possible. For this purpose, the Spanish manufacturer HIMOINSA manufacturers its gas generators, diesel generators, and light towers to withstand many years of use under the most difficult climatic conditions and up to the highest corrosivity category C5I-H.

Around 60,000 generators are produced worldwide every year. Ten subsidiaries and 130 distribution partners are available for interested and existing HIMOINSA customers around the world for sales support and customer service. Powder coating equipment from Nordson plays a key role in its manufacturing process.

The silencer canopies are critical to ensure a durable protection for the sensitive interior of the generators themselves. Their resistance is determined and classified by means of salt spray tests. “Spraying the canopies with salty water simulates the aggressive conditions that many of our devices have to withstand over a long period of time when used in a climate with high humidity and a high salt content,” explains Manuel Ingles, Global Head of Procurement.

“To pass the requirements set in the highest corrosivity category C5I-H, for example, a silencer canopy has to withstand 1,440 hours of extreme exposure to salt spray. This is equivalent to 15 years of use in such an environment. And to maximize the resistance of our silencer canopies, we focus on two aspects: the quality of our steel and the quality of our coatings.”

With this goal in mind, HIMOINSA installed a new powder coating system from Nordson in 2018, initially in San Javier, Murcia, Spain. The highlight: After the metal canopies have been pretreated, they pass through two independent coating processes in succession. In the first coating process, a primer is applied using the conventional Venturi process before the finish is applied using Nordson dense phase technology.

“What may sound simple now was actually the biggest challenge of this project,” says Manuel Ingles. “Both coating processes had to be coordinated in such a way that at the end of an economically and ecologically sensible process, a durable and highly satisfying surface finish was available in the correct coating thickness – and repeatable an unlimited number of times,” he says, summarizing the goal of numerous calculations and tests from the initial phase of the system.

State-of-the-art ColorMax3 powder coating booths from Nordson are used for both coating applications in San Javier. As soon as the conveyor moves a workpiece into the primer booth, eight Encore® LT automatic powder guns start the coating process. Six of them are mounted vertically on a reciprocator, one each fixed at the top and bottom of the powder application zone. For the rare cases of rework, a ninth, manual powder gun is available.

In the second ColorMax® booth, powder application is performed by eleven Encore HD automatic powder guns using dense phase technology. Unique to Nordson, dense phase technology offers patented HDLV® pumps, which deliver a high concentration of powder to the spray gun with only a fraction of the air required by conventional, ejector-pump systems. This spray pattern air is added separately, straight to the spray gun. The separation of powder and air allows powder coaters to fine-tune the powder output for the required production rate and customize spray velocity and pattern size for the best application results. “Because the powder particles hit the surface of the workpiece relatively slowly, they practically do not bounce off.

This results in a high first pass application efficiency, even with complex surfaces,” explains Manuel Ingles, who also immediately names other advantages of the technology. “Of course, there is also less overspray. And because a smaller amount of air only has to be moved relatively slowly, this type of coating is also very energyefficient and environmentally friendly.”

“Basically, we coat in a single 8-hour shift operation,” explains Manuel Ingles “but the powder coating line operates 12 hours a day. Two hours after the end of the shift in the evening and two hours before the start of the shift in the morning, we coat parts so that they are ready for further processing right when we start working.” The coating department team at HIMOINSA is made up of five employees, one of whom works as a system operator. “The low need for manpower in operating the system is a big plus, because in Spain we also suffer a lot from the shortage of skilled workers.”

The line is designed for workpieces with a maximum height of 2,150 mm and a width of 900 mm. “If we run at a conveyor belt speed of 1.5 meters per minute, we coat around 220 square meters in an hour.” There are only short breaks when a color change is due. “The booth, guns and powder center together provide a very efficient color change system. When we change between our six main colors, it only takes about ten minutes for the system to go back in production. This functionality makes coating very flexible and even small batch sizes economical,” says Manuel Ingles with satisfaction.