Cladding is increasingly used to coat metal components. The machines use expensive lasers and are similar to machine tools. The sliding door systems for operator protection are equipped with robust, maintenance-friendly linear guides.
The coating of metal surfaces with another metal - called "cladding" - is slowly but surely gaining wider acceptance. One of the reasons are the new Reach regulations for the use of chromium (VI) that apply since September 2017. “Laser cladding has become a mature technology, but it is still quite expensive due to the high cost of the laser," explains Jelmer Brugman, founder and CEO of Hornet Laser Cladding, a young company based in Lexmond, the Netherlands, which develops and builds laser cladding machines. “The advantage of the laser over arc welding is better control of the molten bath. The adhesion of the layer is also greatly improved by the use of the laser. In addition, laser coating requires less additional material and post-treatment is less time-consuming." According to Brugman, cladding requires special knowledge that is not yet available everywhere. "There's still a lot of work to be done to make the benefits of cladding better known."
Use of laser cladding to increase steadily
Brugman has studied Tool Engineering, but over the years has continued to specialize in metallurgy and welding. At his last employer, Stork Gears & Services, he has been intensively dealt with laser cladding since 2005. After a period as an external consultant, he founded Hornet Laser Cladding in 2013, when he was involved in the construction of three machines for laser cladding. The company, which will move to larger premises in the near future, currently has six employees. "I expect the use of laser cladding to increase steadily in the future. Currently, cladding is a technology that is mainly used for expensive parts whose service life can be considerably extended. But depending on the extent to which prices for lasers fall and melting speeds increase, serial production becomes more and more attractive."
What is cladding?
In cladding, a thin layer of metal is applied to a metal surface by means of arc welding or laser technology. This coating can, for example, consist of nickel or cobalt alloys, but also of stainless steel or carbide-containing metals.
Cladding is used in particular to prevent corrosion or wear. It can also be used to make metal parts more temperature-resistant or to increase their electrical conductivity.
The process is similar to welding: The surface of the metal is heated, causing it to melt, and the top layer can be welded on. The result is a clearly visible welding trace with a width of 1 to 24 mm. After coating, the surface is post-treated.
Machine manufacturer prefers standardization
Brugman compares a laser cladding machine to an inverted lathe or milling machine. “But this machine doesn't mill anything. The main components of the laser cladding machine are the laser, the robot and the control system. All of this is installed in a box-shaped housing. In addition, there are some tools and accessories." The design of the machine can be adapted to the application, but Hornet strives for a certain degree of standardization to keep the production price low. Hornet selects suppliers for the parts and components on the basis of the customer's application and specifications. "We prefer certain suppliers and brands, but we also take the customer's wishes into account. If the client is working with a particular brand of robots, it is not advisable to use another brand for maintenance and maintenance purposes".
Sliding door systems for laser shielding
Hornet uses Rollon linear guides for sliding door systems, which are the basis for machine safety and for laser shielding. Depending on the machine and the circumstances, different types of linear guides are used. For one of the newer machines, for example, Hornet used the TEX45 linear roller bearings from the X-Rail series. These guides and carriages are made of stainless steel and are therefore resistant to corrosion, contamination and very high temperatures, which makes them suitable for use in industrial environments.
The LPS38-473 telescopic slides from the Light Rail series were supplied for another machine. These lightweight telescopic guides withstand high loads and absorb shocks elastically. They are easy to maintain and have a long service life. With regard to the quality of the guides, Brugman praised Rollon's advice as to which guides should be used most effectively in the cladding machines.
* Klaus-J. Hermes is Head of Marketing at Rollon GmbH in 40589 Düsseldorf, Phone (02 11) 9 57 47-0, email@example.com
This article was first published by spotlightmetal.com.
Original: Stefanie Michel / Translation: Alexander Stark