Enhancing the productivity of Additive Manufacturing facilities through PBF-LB automation

Additive Manufacturing has already enabled countless innovations across a wide range of sectors, including aviation, medical and electrical components. Design freedom and rapid iterative prototyping have allowed designers to reimagine components without the limitations of traditional manufacturing methods, while also cutting production costs.

While the Additive Manufacturing production cycle has been optimised and simplified for both polymer and metal applications, as any production manager will tell you, every moment spent doing something other than manufacturing components is considered unproductive waiting time. Whilst significantly more productive than other manufacturing methods, Additive Manufacturing still has processes that fit into this category. In Laser Beam Powder Bed Fusion (PBF-LB) these include build preparation, de-powdering, and cooling time prior to post-processing (Fig. 1).

EOS has worked for decades to improve the efficiency of both its metal and polymer AM machines with improved software, faster build speeds, and new light sources. Combining a larger build chamber and powerful quad lasers in machines such as the EOS M 300-4 and EOS M 400-4 has also dramatically improved efficiency in serial production environments.

Performance enhancing levers also exist outside of the AM build space

Whilst evolutions in Additive Manufacturing have improved efficiency inside the build chamber, unproductive waiting time is predominantly lost outside it in the wider production process. A typical EOS M 300-4 or EOS M 400-4 metal AM machine will spend an estimated 60% of its production time building parts. While these machines have some of the most impressive build speeds, at the end of a job, some 30% of time is still lost waiting for unpacking. A further 9% makes up the cool down and depowdering processes.

Whilst this idle time is typical across the industry and offset by productivity gains in other areas, EOS is seeking to claw this time back for customers and sees automated production as the key. Jens Karnapp, Product Line Manager for Metal Systems at EOS explains, “For us, it was all about squeezing the unproductive time out of the production process. We wanted every possible moment to be productive for our customers. Working with our partners to introduce automated production means we have dramatically increased the ‘laser-on’ machine utilisation possible with EOS AM machines.”

Working with Grenzebach Maschinenbau GmbH and Volkmann GmbH, EOS has introduced a new Dual Setup Station (Figs. 2, 3) and complete powder handling solution, that eliminates some of the biggest bottlenecks, improves machine utilisation, and supports multi-machine production environments.

Increasing available build time with Grenzebach’s Dual Setup Station

With nearly a third of production time spent waiting for unpacking, EOS has worked with Grenzebach to develop the Grenzebach Dual Setup Station – EOS Edition. This system accepts two exchangeable frames, which are automatically swapped in the AM machine when the first job finishes. Once swapped, the AM machine automatically starts the second job.

This approach eliminates waiting time, pushing productive machine utilisation for building parts up to 90%. The ‘laser-off to laser-on time’ is under 30 minutes, with no worker interaction required. While the first job is being unpacked by operators, the second job is already underway. Once cleared, the first frame can be prepared and ready to go again as soon as the second job has finished. With this setup, the cool down of the build job can now be done in the Dual Setup Station, rather than in the M 400-4.

Jobs can also be scheduled to start unattended outside a production line’s normal shift hours. A build could be configured to start running before shifts start, overnight, or even allow unattended 24/7 availability of machines throughout the weekend.

Leveraging Volkmann’s expertise to automate powder handling

Powder handling is another time-consuming task that impacts the productivity of the production line. From filling machines to de-powdering and reprocessing powder extracted from the build space, they all take time. The Volkmann Automated Powder Handling Solution – EOS Edition automates these tasks, improving productivity and enabling staff to spend their time on higher-value-added tasks.
The closed-loop system enables the rapid removal of metal powder during unpacking, automatically sieving and recycling it back into future build cycles.

The basic system can be applied to a single machine or, by combining different components, build a fully closed loop powder circuit that can serve everything from a single machine to a manufacturing cell of multiple EOS metal AM machines.

The central system component is the PowTReX – EOS Edition. This unit combines powder extraction and automatic, ultrasonic sieving of the used powder. The powder is then made available for either manual refilling of the machine or automatic conveying to the vHub 250. This automatic process lowers both the safety risks of staff conducting these tasks, as well as the risk of powder contamination. The PowTReX can also be used with a standalone AM machine.

The vHub 250 – EOS Edition is a 250 litre powder reservoir and vacuum conveying system that can be used to transport powder to machines and receive recycled powder. It acts as a buffer unit to secure powder availability throughout the powder circuit (Fig. 4).

The final component to complete a fully closed powder handling circuit is the vLoader – EOS Edition. It automatically fills a gravity-fed metal AM machine on demand and can include an optional dryer module to vacuum dry powder before introduction to the machine. This can improve the flow properties of the powder and the quality of the final components.

Automation innovation

In a constant search for improved efficiency and reduced downtime, EOS has looked outside the machine as much as it has inside. Manufacturers can now look to increase the utilisation of their machines, deploy additional production cycles, and employ staff in other aspects of the serial production process. Whether it is a single machine, or a larger production cell of multiple AM machines, the new Dual Setup Station and Automated Powder Handling solutions can significantly improve the performance of AM production equipment and better leverage investments in production capacity.

Author

Sebastian Becker
Head of Product Management Metal
EOS GmbH
www.eos.info