3D Printing for the Chemical Industry

Hand hole seal of an agitator, manufactured with ACEO®‘s multi-material 3D printing technology. (Photo: ACEO®; Wacker Chemie AG)

WACKER’s Central Engineering Department acts as an internal service provider for research and development and production. This includes all technical services relating to the mechanics of a wide variety of machines and equipment. As part of its internal vocational training program, a team led by Bertram Reiter and Jürgen Sigl developed a component for a machine together with ACEO® that avoids glass breakage during classroom tests and thus saves high costs.

Working at WACKER’s Central Engineering Department is as versatile as it is demanding. It deals with the entire process of manufacturing various chemical substances. These include the plastics workshop and the glass workshop. This involves the design of every single machine and every single component used in it – such as a boiler that is subjected to very high pressure during operation. In order to convey the complex correlations to trainees, one thing is essential right from the start of the training: practical testing.

Every year, the WACKER Foundation BBiW trains about 60 chemical technicians. BBiW is responsible for the training of apprentices at WACKER and its partner companies. The aim is not only to teach the prospective chemical technicians the curricular training content, but also to turn them into well-trained specialists who are taught as much know-how as possible in order to gain a direct foothold in industry. The foundation puts great emphasis on modern equipment and facilities that are suitable for vocational training, where technical knowledge and practical skills can be acquired and practiced.

In order to meet these high demands, not only the availability of equipment and machines is required, but also the availability of machine parts that can withstand the conditions of the trainees’ testing. That is why Peter Tischler, process engineering trainer, Bertram Reiter, lab maintenance process engineering, and Jürgen Sigl, head of machine construction, have set themselves the goal of constantly introducing and testing new technologies. 3D printing offers various possibilities for this and the team tries to apply this technology wherever possible and to put it through its paces.

Agitators are used time and again in various technical applications in the chemical industry. These agitators are actually sealed due to their contents, but require a so-called hand hole to allow, for example, saline solutions to be added during stirring. During the training, hazardous substances are avoided in order to keep the risk of injury as low as possible. Around the hand hole there is typically glass in the form of a hood above the agitator, as it is a very acid-resistant material.

Peter Tischler closes the hand hole of an agitator – without proper handling the glass hood can quickly be damaged. (Photo: ACEO ®; Wacker Chemie AG)

The previous construction of the agitators every now and then led to breakage of the glass – partly because of a lack of tightness, partly because too much pressure was exerted on the hand hole by trainees. As a result, the glass in the immediate vicinity of the hand hole was regularly damaged – individual parts broke away or sometimes even the entire glass hood was destroyed. The breakdown of such a system (which happened at least once a year) not only resulted in repair times, but also in high costs.

To minimize these downtimes, the team looked for a seal that could withstand both positive and negative pressures and minimize the likelihood of glass breakage. Silicones are the most suitable material for this type of seal due to their versatile properties. Among other things, they are elastic, heat-resistant, can withstand high pressure and provide media resistance. In contrast to the time-consuming and costly injection molding process, 3D printing is particularly suitable for creating a prototype. And so the team turned to their colleagues at ACEO®, who have been pioneers in 3D printing with silicones since 2016.

From left to right: Jürgen Sigl, Bertram Reiter and Peter Tischler test the ACEO® seal prototype on an agitator. (Photo: ACEO ®; Wacker Chemie AG)

After initial discussions with Vera Seitz (Product Design Engineer) and Ralf Mezger (Production), hardness was determined that could be used for the application. ACEO® suggested to use different hardness in one seal, which is possible with the multi-material printing technology ACEO® presented in 2019. Jürgen Sigl then created the CAD file and ordered the first part via ACEO®‘s web shop. “The webshop is a great thing. After the CAD upload we received an offer and our first part in a very short time”, Sigl praises the cooperation. “This type of additive manufacturing is clearly the best option for us”.

The success of the 3D-printed silicone seal also speaks for itself. It held up 100% in a stress test lasting several hours, not least thanks to the multi-material print that consists of two different silicones with different hardness. “This way we can really show everything WACKER can do in real life during training,” adds Peter Tischler. “At the same time, we are reducing costs by finding a seal that minimizes the risk of glass breakage during testing. The new seal has been in use at BBiW for more than six months.

The seal produced with ACEO®‘s multi-material 3D printing technology is already in service at BBiW. (Photo: ACEO ®; Wacker Chemie AG)