These materials are melted into workpieces using methods such as selective laser sintering. However, "After the production process, the cooling ducts, cavities and support structures of the metal components are still full of fine powder," reports Andreas Hartmann, an engineer and one of the directors of Solukon Maschinenbau GmbH. Previously, this powder needed to be manually blown away with air or shaken off. "For more complex components, that might take as long as seventeen hours," says Hartmann.
In 2015, at the request of a leading car manufacturer, the company developed and built the first automated line of cleaning booths for large, laser-melted metal components. Two years and 12 models later, in 2017, came the simpler and less expensive SFM-AT300 variant – for use with smaller and lighter steel, aluminum and titanium alloy components. These easy-to-use machines really hit the mark with Solukon's customers and they are highly sought after in the automotive sector and in the energy technology and aerospace industries.
Solukon Maschinenbau GmbH was founded in 2013 by engineers Andreas Hartmann and Dominik Schmid in the Bavarian town of Stadtbergen, near Augsburg. The two had previously gained experience as lead design engineers for a major manufacturer of 3D printing systems. Initially established as an engineering consulting company – for the development and design of specialist machinery such as packaging machines, freezers and 3D printing systems – its operations now include the planning, design, manufacture and installation of cleaning booths and unloading stations for laser-sintered components
We use LOGO! 8 to control our machines because it offers lots of functionality at low cost.Andreas Hartmann, engineer and one of the directors of Solukon Maschinenbau GmbH
Cleaning booths remove loose metal powder from the laser-melted metal components using targeted oscillation inside a sealed process chamber. The component and its mounting platform are clamped onto a turntable for this procedure. The turntable swivels around one or two axes for a preset amount of time. "This fluidizes the powder so that it can drain off," Hartmann explains. It is then collected in a hopper and discharged into special containers through a gate. After the automated cleaning, an operator can then reach in through glove ports to post-clean any complex cavities or ducts as needed, using compressed air or an inert gas.
Safety is the top priority in these procedures. If a component is made from any reactive, explosive material such as an aluminum or titanium alloy, the process chamber can be made inert using a protective gas. This also protects the material as the dust is no longer prone to oxidation and thus reusable. Thanks to the closed cleaning circuit, it is all retained and can be recycled.
"We use LOGO! 8 to control our machines because it offers lots of functionality at low cost," says Hartmann. The logic module is supplemented by two digital expansion modules – the DM16 24R and the DM8 24R – along with a SITOP PSU100S power supply unit. With the exception of safety monitoring of the inerting process, Solukon can now automate all the essential functions of the cleaning booth.
These include controlling the motor as LOGO! 8 permits easy timer-controlled operation of the swivel arm to limit switches. At a preset cleaning time, the swivel arm stops vibrating and moves back to its home position. Hartmann says the time savings is substantial. "This automation enables time savings of about seventy percent on post-processing compared to cleaning by hand," he reports.
The controller also communicates with the safety PLC during inerting, and only activates automatic swiveling after the chamber has been filled with protective gas. A traffic light signal switched by LOGO! 8 indicates to the user whether the system is ready to operate, or whether cleaning is complete. The logic module also sends digital status signals that control external peripherals, such as a material conditioner which vacuums the floor of the booth to empty it after cleaning.
"LOGO! 8 offers us lots of possibilities to meet customers' needs and wishes," says Hartmann, with an eye toward the future. "They extend from control and monitoring, through web servers, to messaging on cell phones with the LOGO! CMR module." Other benefits of the controller are its compact design and user-friendly operation. "I'm certainly no programmer," Hartmann asserts, "but with LOGO! I can easily change, test or simulate functions myself."
This is opening up new opportunities for Solukon. "The machines for 3D printing are now going into production," Hartmann reveals. "We are also looking to integrate them into the automated factory. That also means automating booth loading by robots, for example." The company intends to continue using Siemens controllers in the future. Hartmann concludes: "As makers of specialist machinery in a highly critical, high-end sector, we have to be able to rely on the manufacturer and its products one hundred percent."