Creating space for design
Automated coating opens up new design possibilities
Individualizing stair construction: With an automatic coating system, a medium-sized joinery can now design stair treads as desired and also accept additional painting orders.
A medium-sized joinery in the staircase construction segment invested in an automatic spray-painting system from Venjakob and thus set the course for a reorientation of the family business. Individual customer requests in the coating of wooden stair treads can now be realized just as quickly as painting orders for outside companies from the interior design sector. In this way, the family business ETS can ensure the continuity of the company for the next generation.
ETS Treppenbau und Schreinerei GmbH employs 26 people at its Dingdorf site in Rhineland-Palatinate. In addition to the managing directors Albert and Klaus-Peter Ernzer, the three sons are already working in their parents' business - two of them, Jonas and Lukas Ernzer, already have their master craftsman's diploma in their pockets. The company specializes in the construction of wooden stairs, primarily for private customers, prefabricated house builders and joineries.
In order to manufacture stairs to measure and according to customer requirements, a lot of manual work was necessary up to now. However, the family business began to feel the shortage of skilled workers more and more strongly. "You have to find good painters first," says Alfred Ernzer. "That's why we started thinking about automating the processing of surfaces," adds Klaus-Peter Ernzer. The desire to increase quality and save time played a major role in the decision-making process. "Our customers increasingly want the surfaces of their stair treads to be color-matched to the interior, especially the existing floors. For this purpose, colored stains or RAL colors are used as water-based UV varnish, which we were previously only able to varnish on the manual spraying stand," reports Alfred Ernzer. The roller coating system available at the plant could only be used to apply clear coat. For painting the edges, additional manual work had to be carried out.
Plant is adapted to the new hall construction
Finally, the Ernzers family decided to invest in a Venjakob spray painting system, including dust removal and drying. In the future, the surface treatment process was to take place separately in its own hall. A new hall with an area of around 500 square meters was planned for this purpose. The ceiling height was low, as the hall was built directly onto the existing workshop at the same height. Accordingly, the coating line was to be designed to save space. The new coating line was to be tailored exactly to the needs of ETS. It was important that utilization beyond the company's own stairs should be possible in the future. After all, the first major order had already been received - 5,000 square meters of particleboard for interior fittings were to be coated. The new Venjakob plant, which allows fast color changes and has short drying times, is predestined for this. The entire plant was built in a U-shape with a rake angle transfer for moving the workpieces. It is designed for workpieces from 300 x 100 x 10 millimeters up to a maximum of 5300 x 1300 x 100 millimeters.
The process sequence begins with the workpieces being placed on the belt conveyor by hand. Length markings for the workpieces have been applied to simplify the process. The wood is first automatically dedusted and preheated via an IR preheating module. The workpieces are then conveyed to the Ven Spray Smart spraying machine. This is equipped with one coating supply line each for UV clear coat, UV color coat and for stain.
The stair treads are coated with four spray guns, which coat the surfaces and edges equally. A temperature-resistant belt conveyor transports the coated steps through a covered evaporation zone into the water-heated drying channel. This consists of two nozzle drying channels and an angular transfer for transferring the batches. In the subsequent UV drying channel, the stages coated with clear or colored lacquer are cured.
"The aim was for the workpieces to come out of the system dry after the base coat with color or clear coat, so that the intermediate lacquer sanding and then the top coat can take place afterwards," explains Christian Schulze, sales engineer at Venjakob. The time required for a painting run, from the placement of the workpieces to acceptance, is approximately fifteen minutes.
The system is controlled via a central operating unit. The existing coating recipes are stored in the control system - calling them up is simple. "All important parameters, such as drying times, are stored in the recipe management system. We have carefully coordinated these parameters with the customer and the coating manufacturer," says Schulze.
EU directive-compliant coating, pickling, drying
The new coating line from Venjakob can be used for coating, pickling and drying. The entire coating line - from the spraying machine with three coating supply lines to the UV drying channel - is designed to use the desired water-based UV coatings and water-based stain, and is one hundred percent compliant with EU environmental directives. In terms of time savings, Alfred Ernzer says, "We can now easily coat twice as many stair treads." The Ernzer family was also impressed by the quality of the surfaces: "UV curing, which can now also be used for the colored surfaces, makes the coating much more resistant and scratch-resistant."
The investment was worth it, they agree at Ernzer. "Yes, there were cheaper offers. But the decisive factor for us was the expertise of the Venjakob employees and their good reputation," says Alfred Ernzer. The plant was planned and implemented exactly according to the needs of the company.