Masterful Touch

When the order has been received and planned, the first material step in production is dispersion. This takes several hours. During this time, Schuhmacher and Amaral monitor both the temperature and the particle size, which can be anywhere from 50 to 300 micrometers depending on the recipe.

Timo Dorigo, who is in charge of wet paint production, knows the importance of continuous quality control. “We have to respond immediately to any irregularities,” he says. Because nearly every product takes a slightly different route through the production process, it’s extremely important for everyone involved to communicate well with each other. “With 3,000 to 5,000 active formulations and many overarching processes, we constantly have to check the status and progress of our production processes.”

Every morning the department heads meet for a “paint round” in which they go through the production steps together. “We immediately see if we have to intervene somewhere. It keeps everyone informed and we all know if there’s a problem,” says Dorigo. He insists on a clear focus. “We start by talking about anything that’s not working right. Afterwards, I’m just as eager to hear the success stories.”

The best result of this measure to improve communications has been a considerable increase in production. The company can also do more reliable planning to utilize the plant’s capacity.

New machinery in the grinding room has shortened throughput times for the bead mills. Endurance is of the essence here too. For some products, a hundred or more hours are needed to grind the materials down to the desired particle size. Christian Wiesing does regular tests with a grindometer. This device looks like a thick ruler made of stainless steel. A channel has been machined into it, with a depth that decreases at a linear rate from 200 micrometers to zero. A few drops of paint are put into the deep end.

Wiesing uses a squeegee to pull the paint toward the zero end, and watches for the first smears in the paint film. A scale shows him the particle size of the paint in micrometers. “We also have to keep an eye on the temperature when grinding,” he adds. “We can’t let it exceed 70 degrees Celsius, or the paint will be ruined.”

Sampson Apler’s great treasure is his experience. He uses a large scoop to weigh special-effect pigments for “Valencia Orange.” This recipe lists five ingredients, although other paints can have up to twenty. The amounts are listed on a production order with an A4 (approximately letter-size) format, which accompanies all steps of the process. “We have to work precisely,” Apler emphasizes. Some of the ingredients for this base coat have to be weighed down to a few grams. That corresponds to the exactitude of a letter scale. A scanning system helps to ensure that all the raw materials are included.

Depending on the product, there can be as many as 20 steps to go through. On a typical day, one hundred metric tons of primer, base coat, top coat, and clear coat, including semi-finished products, leave the factory—in containers ranging from one kilogram to a metric ton in size. The main plant in Stuttgart will be expanded by 2,000 square meters by the end of the year. “That will mean shorter distances,” says Daniela Off, who heads base coat production. As Dorigo adds, “We’re optimizing our material flow, and we’ll have better transport routes and sufficient buffer zones.”

The crux of the production process lies in determining the color. But only a few employees have a ‘license to color.’ “It’s the most exciting step,” says Off. “You really have to know what you’re doing. And not everyone can do it.” One person who has been making the right decisions here for twenty years is Michael Körper. “The hardest part is to meet the requirements placed on each individual paint.” One can never claim to know all the secrets of coloring, he adds, because customer wishes are constantly changing.

Körper spends nearly two-thirds of his working day at the computer. He uses measurement values, customer specifications, and his own experience to develop the precise coloring strategy. A color tone navigator that was developed at Wörwag and is continuously optimized helps him in his work. It is essentially a digital color chart. It records every production order, and its database stores his work for future batches.

In making his decisions, Körper draws on proven paint recipes as well as on feedback from the quality center and modified application specifications from customers. “There’s always more to learn,” he observes. “Coloring is teamwork.” The process can take several days, because it’s not only about color. Gloss, special effects, coat thickness, and material properties all have to be taken into account as well.

Color samples are repeatedly sent to the paint center. The paint is put on panels measuring 10 by 14.8 centimeters, simulating customers’ large-scale applications as precisely as possible. Juliana Donner, a certified automotive paint specialist, is one of only three women working in production at Wörwag.

“I’ve always been fascinated by the huge spectrum of things you can do with paint,” she says, mentioning the numerous metallic paints with flop effects as just one example.

To do a trial coat, she pours a cup of “Electric Green” into the paint system, inserts a plastic panel for the substrate, and starts the procedure. A maximum of two coats are applied on a light or slate-grey primer. The plate then lands on Körper’s desk.

And the process starts from the beginning again: coloring, painting, testing. Until it’s right. Cycle upon cycle. Finally the tone is perfect. A masterful touch. “Metallic blue and orange are the trickiest,” says Off, “especially because producers keep narrowing their tolerance ranges.”