October 9, 2018
Quality guarantees in the laser process
They position parts to the exact nanometer, control laser processes, and ensure pure, dry air in the installation space. Suppliers play an important role with regard to the continuing success of the laser industry.
The laser beam darts over the powder bed and, with the selective melting process, produces complex components. 3D printing is fascinating. But it works only under defined conditions. For example, the micrometer grained powder tends to clump together even at a low humidity. And the 3D printing process itself requires a protective gas atmosphere with expensive inert gases like argon or nitrogen, which must be circulated and cleaned thoroughly to remove laser fumes and dust. These are, in some cases, toxic, corrosive nano particles that would float around the installation space if they were not extracted.
At first glance, the technology that creates the optimum conditions for 3D printing and other laser processes doesn’t appear very spectacular. But it has an important influence on the quality, precision and, hence, the success of the laser industry. If the inert gases were not cleaned continuously, the processes would not be stable. Without precise extraction and filtering of the laser fumes, workplace safety and the air quality of the systems could not be guaranteed. And only modern dehumidification technology can keep the materials that are used in optimum condition.
Complex and dependent on the respective process: air monitoring
Suppliers such as ULT AG and TBH GmbH provide air treatment systems to ensure optimum conditions. Depending on the process, storage or cartridge filter devices are used where extraction devices with different suction capacities feed the process air. All influences on the laser processes are taboo. But effective removal of laser fumes and particles must be ensured no matter how far away the source of the pollutant is. Even a few centimeters make a world of difference here.
In view of the many different laser processes and the materials that are processed, the experts analyze every process in detail, adapt their solutions to suit the situation and, thanks to consistent modular drives, primary and secondary filter modules, they are still able to remain within budget. With consideration of Industry 4.0, air treatment systems are also becoming smarter. For example, the suppliers offer digital control systems that monitor and document process parameters and filter conditions and report deviations so that users can adjust the systems.
Precision guarantees: drive and positioning technology
Suppliers of drive and positioning technology are also enablers who play a major role with regard to the quality of laser processes. This includes precise, fully automatic wire feeding in laser soldering and laser deposition welding processes with the help of high precision stepper motors; if necessary, they can feed wire with more than 4,000 steps per second. But also ultra-short pulse laser technology. Where light pulses last just atto, femto, or pico seconds, precise actuator engineering is needed to align the prisms, mirrors, and filters that guide the laser beam to its target. Stepper motors don’t need sensors, as they derive their position from the number of steps. According to Faulhaber, this is now so reliable that no steps are lost even with thousands of steps per second. Microsurgeons and scientists using multiphoton microscopes can be sure that no laser pulses miss their target. Precise drives also smooth the way for the success of industrial laser processes: Where lasers weld or solder thin metal sheets, sinus motors with coordinated gears align the fast moving laser heads accurately.
No matter whether it’s in industry, medical engineering, or science: thanks to their flexibility and precision, laser processes are on a winning track. Piezo drives now allow microscope objectives to be positioned in increments in the sub-nanometer range. They also offer travel ranges of up to 450 micrometers. The ultra-precise nanopositioning stages from Aerotech GmbH are just as accurate and flexible. They align work pieces precisely on three axes—and also work in the sub-nanometer range.
Föhrenbach GmbH also specializes in precise direct drive and positioning systems, which they produce themselves—from the motors to axes measured using laser interferometry. This strategy is based on the conviction that the key to quality and productivity in laser processing lies in the coordinated interaction of the positioning system and the tool. At LASER World of PHOTONICS 2017, the company stated that it has repeatedly worked together with customers from the laser industry to produce systems with levels of accuracy and productivity that initially seemed impossible. That puts the suppliers’ contribution to the success of laser technology in a nutshell: their expertise helps the industry to keep stretching the limits of what is possible.