Depowdering is not postprocessing

This provocative statement comes from the cover story of the latest issue of ADDITIVE FERTIGUNG magazine. Find out in this article why we at Solukon see industrial depowdering as an important part of the manufacturing process instead.

Einleitung

Almost ten years ago, Andreas Hartmann and Dominik Schmid founded Solukon Maschinenbau GmbH. The company from Augsburg, Germany, is now the go-to for depowdering LPBF metal parts. With pioneering innovations, the depowdering specialists have successfully raised the bar for unpacking complex geometries again and again

The story of Solukon began in 2012, when Andreas Hartmann and Dominik Schmid founded their own engineering office for special-purpose machines. However, the real success story started in 2013, when a customer from the automotive sector inquired about a depowdering solution for LPBF parts. One year later, the partners shipped the first system. “Since we both came from the voxeljet AG environment and therefore had experience in handling powder materials, the inquiry struck a familiar chord and in a relatively short time, we were able to provide a solution that met the customer’s requirements,” recalled  Hartmann. The main requirements for the first system focused on safety in general and occupational safety in particular. “In powder-based AM metal production, we frequently dealt with reactive materials with particle sizes that could penetrate the lungs. This is why it was obvious early on that a closed system would be necessary for depowdering these types of parts. It would have to enable inerting, and contact-free powder handling as well,” said the CEO.  

Wide range of requirements

It quickly became clear that depowdering metal parts made with additive manufacturing involved several additional challenges. Metal AM parts often have complex inner geometries like channels and conduits, narrow cavities and tight support structures. Significant amounts of powder can remain in all of these geometries. Inadequate depowdering can lead to clogged channels, which in turn have a negative effect on the function of the part. And the residual powder in support geometries is lost when the part is sawed off the build platform. “All of these challenges show that depowdering is a key process step in additive metal part manufacturing with powder materials. We no longer classify depowdering as postprocessing—as a downstream process step—but instead as a decisive part of the manufacturing process,” Hartmann explained in detail. There was clearly sufficient demand for suitable depowdering machines for AM parts, which led to the founding of Solukon Maschinenbau in 2015. That same year, the company shipped the first SFM-AT800 – in the beginning, an automated system with programmable 2-axis rotation, vibration and inerting with protective gas.

Cleaning with vibration excitation

Powder materials in additive manufacturing must have a specific degree of flowability to ensure that the manufacturing processes are smooth and reliable. During the manufacturing processes, however, the powder layers are frequently compressed to the point that the resulting powder cake has trouble trickling away, which makes depowdering much more difficult. “We had to deal with this problem at voxeljet back in the day and were therefore aware that we had to find a way to improve the flowing properties of the power. There are basically two workable solutions: One method involves knocking the build platform with the workpiece on it, while the other involves applying vibrations to the system, which makes the powder act like a liquid. Depending on the material, knocking or vibration—or a combination of the two—leads to the best results,” said Hartmann. “For delicate structures, piezoelectric excitation at ultrasonic frequency replaces pneumatic excitation.”

Launch of SPR-Pathfinder software as milestone

In 2019, a collaboration with Siemens and, in particular, their idea generator Christoph Kiener led to the development of the SPR-Pathfinder software solution. Using the CAD file of the build job, the software detects the inner channels and, in advance, calculates the optimal motion of the swivel system of the Solukon machines for
the cleaning operation. When it comes to cleaning time and cleanliness, this is particularly interesting for parts with multiple twisted channels, like the cooling channels in injection molds. As early as the design phase, software users can check whether or not the geometries they designed can be completely depowdered and adjust the design if necessary. This way, parts that would probably deliver unsatisfactory depowdering results are not printed at all. “This development was another milestone on the way to establishing our depowdering solutions in the market. Safety-critical sectors like the medical industry and the aerospace industry have the highest standards of cleanliness and freedom from powder for their parts. With our technology, we can offer exactly that, which makes us the world’s first choice when it comes to depowdering metal parts. After the joint development phase with Siemens, we took over SPR-Pathfinder in 2022 and turned it into a commercial product. Since then, we have continuously developed it further,” explained Hartmann. He added: “For us, it has always been important to align our developments to the needs of the market.This also means that we tend to implement a moderate approach when it comes to company growth. We have managed to do well without third-party funding, which is something we are very proud of.

Analyzing and understanding key industries

The key features of Solukon machines are outstanding workmanship and high technical maturity. To become established in markets like the aerospace industry and medical technology sector, the highest standards must be met. “These sectors in particular demand consistently high quality that is reproducible. To deliver this, it is important to understand the criteria that determine quality and transfer them to an automated process. We have combined the two steps in our SPR® Smart Powder Recuperation technology. Alongside consistent, automated, path-guided depowdering with adjustable vibration, this also involves recovering as much residual powder as possible. Powder materials are a valuable raw material, and they must be recycled to the greatest possible extent,” said the CEO to summarize the market requirements.

Increasingly large LPBF systems whose build platforms must be depowdered are being launched, and Solukon reflects this in its constantly growing machine diversity. SFM-AT1500-S is the latest flagship of the portfolio. This depowdering system was specifically developed for cleaning extra-high, heavy and complex parts such as rocket engines. The system can accommodate parts up to 1,500 mm high with weights of up to 2,100 kg. Alongside the comprehensive range of machines for depowdering metal parts, Solukon offers the SFP series with depowdering solutions for polymers.

Success with growth potential

Andreas Hartmann summarizes the success of Solukon like this: “We started out as an engineering office with the goal of offering industrial solutions for a variety of sectors. Ten years ago, we identified a niche that lacked practical solutions and developed our depowdering solutions. Our customers benefit from our grasp of technology and first-class engineering work when it comes to implementing our systems. Reliability, high quality standards and innovative power are at the top of our list—and our international customers also appreciate these qualities. We offer our customers more than the highest level of machine quality and reliable cleaning results: providing customer-specific consultation with our experts is our other distinguishing feature. Material-specific forms of excitation, clamping systems, handling support structures, setting software parameters, etc. are all topics that our competent teams of experts have answers for. In depowdering tests with real parts, interested parties can also see the quality of the cleaning process for themselves in advance and without obligation. We are optimistic about our continued success in the next ten years and look forward to accepting new challenges from the market.”

Artikel jetzt im E-Paper des Magazins ADDITIVE FERTIGUNG lesen

This article is the cover story of the magazine ADDITIVE FERTIGUNG. Access the e-paper here (Geman version only).