Handmade bicycle frames sustainably produced thanks to powder coating

The bicycle is more popular than ever. With a sales increase of up to 900 million euros in the Corona year 2020, the bicycle industry was considered the big non-food winner of the pandemic. This was the result of a study by the IFH Cologne trade research institute and BBE Handelsberatung. This development is also felt by the company Krüger Fahrrad- und Fahrradrahmenbau from Spenge-Wallenbrück in North Rhine-Westphalia. "Our work has always been valued. Since the Corona pandemic, however, we have experienced a significantly higher customer demand," says Managing Director Michael Krüger.

In 1967, his father Dieter Krüger founded the company as a supplier for the East Westphalian two-wheeler industry. The company grew quickly and specialized in the field of bicycle frame construction. After moving from Bielefeld to the current location, the production of complete bicycles was also started. Since 2008, the family business has been managed by Michael Krüger in the second generation. "A bicycle consists of thousands of individual parts," he describes his work. "Making a bicycle from these individual parts is much more than just a job for us. It's a passion!"

Environmentally friendly supplement to liquid coating

Because of this very passion for two-wheeled vehicles, Krüger is always on the lookout for the optimal solution for building the bicycle frame, which determines the character of the bicycle in terms of appearance and geometry. "The frame is the most important part of the bicycle: it has the function of a spine and holds everything together," explains Michael Krüger.

To give the frame that special "something," a few steps are necessary: After a primer as rust protection, an adhesion primer is applied for the color shade. Depending on the customer's requirements, Krüger has previously used liquid paint or powder at this point. Acrylic paint is then applied in the desired color shade. Finally, a clear coat of polyester powder is applied to protect the color and frame, and the final curing of all layers takes place in a chamber oven. "In the long term, we wanted a more sustainable way to paint our frames," explains the managing director. Together with Oltrogge from Bielefeld, engineering partner in the fields of compressed air and surface technology as well as machine tools, a way was sought to make the painting process more effective and environmentally friendly. In the end, Krüger Fahrrad- und Fahrradrahmenbau decided on a new system for more effective and sustainable powder coating, especially for the application of the primer and the final clear coat.  

Resource-saving, cost-saving and at the same time scratch and impact resistant

Powder coating is a process in which paint particles are applied electrostatically to the electrically conductive bicycle frame to be coated by means of a spray gun. Krüger now uses a new WAGNER SPRINT manual system for coating, which is particularly suitable for small batch sizes and frequent color changes. The particles adhere to the frame due to the electrostatic charge. The paint is then cured into the frame in an oven or dryer.

Krüger benefits from the numerous advantages of the process: Compared to liquid painting, powder coating is solvent- and emission-free and therefore environmentally friendly, and also extremely resource-efficient. Powder that is not needed can be collected and reused for the next coating process. This effectively saves costs at Krüger. In addition, powder-coated frames and components are characterized by optimum protection against weathering and corrosion, and are highly resistant to scratching and impact. Managing Director Michael Krüger is enthusiastic about the advice and the solution that Oltrogge provided: "With the new powder coating facility, we can offer bicycle frames that are sustainable and at the same time even more robust. Anyone who rides one of our mountain bikes through the mountains no longer has to worry about their paint getting scratched by small stones or the paint harming the environment."