Porous materials, membranes, and multilayer systems play an important role in various applications, including filters, sensors, cooling structures, flow regulation, and more. The fact that Exentis’ additive screen printing technology uses paste feedstocks means that material composition can be exactly tailored to the requirements of a given part. Moreover, the ability to combine porous materials with micro-precise structural part designs unlocks remarkable potential for innovative applications.
A printable paste made from powdered materials and binders is the basis of Exentis 3D screen printing. Since Exentis additive manufacturing technology uses screens, ultra-fine micron-scale features could be incorporated into the component design. Printed parts are manufactured layer by layer. We can change the screen as well as the paste during the process, therefore it is possible to produce more than one layer of varying porosity and/or design within one component structure.
Porous materials in additive screen printing
Feedstock pastes for Exentis 3D screen printing can be made from a variety of common industrial ceramics or other material powders. They are mixed with binder materials to form a printable paste feedstock. Additionally, when a porous material is needed, a pore-forming agent is added to the mixture.
These organic substances function as placeholders within the paste. During the sintering process, the pore-forming agents burn out and leave a controlled porosity. An example: this method allows porosities of up to 50% using 316 L steel.
The porosity is precisely calibrated to ensure the structural strength required for the component. This balance between porosity and stability can be adjusted by varying the size and amount of the pore-forming agent particles.
Exentis experts ensure results that meet your requirements
The required porosity of a material depends heavily on the intended use of the manufactured part. Therefore, the composition of the pastes used for printing is crucial. The Exentis team includes chemists, material specialists, engineers and 3D screen printing specialists. They ensure that each customer project receives a customized paste – if needed – and an optimized part geometry that maximizes the performance of the component.

Exentis material experts at work
The perfect combination of porous material and component design
Depending on the function of a component, both porosity and part design can further optimize performance. In this area, additive screen printing technology offers the advantage of integrating micro precise structures directly into the components. Furthermore, 3D screen printing often simplifies production by combining several steps into one, unlike traditional technologies.
Efficient filtration: the role of porous membranes in liquid and gas purification
Porous materials are highly effective for filtering liquids and gases, acting as specialized membranes. These membranes are characterized by their large surface area relative to their thickness, functioning as selective barriers that retain particles based on size while allowing fluids to pass through.
In the filtration process, filters typically serve as the initial stage by capturing larger particles, while membranes subsequently filter out smaller ones. This two-stage approach ensures highly efficient purification.
An example: a membrane made from porous material based on 316 L
In a specific customer project, a porous transport layer (PTL) made of stainless steel was developed for use in hydrogen production using electrolysis. The porous transport layer plays a crucial role in ensuring efficient gas and liquid transport to a filter membrane. This transport layer consists of three layers of materials with varying porosity, combined with a specialized component geometry. As a result, this design not only enhances the mass transfer but also improves performance of the electrolysis process.
3D screen printing facilitates the creation of such transport layers by allowing for customized porosity in combination with optimized part design.

An additive screen printed part made of porous materials
Conclusion: 3D screen printing unlocks new possibilities for porous material structures
Overall, Exentis’ technology offers several advantages that can play a crucial role in applications where porous materials are required:
- Direct integration of porosity into the material
- Combination of porous structures with micro precise geometries
- A simplified manufacturing process which reduces time and cost
- Ability to create complex components that previously required multiple components
Do you have components where the porosity of the material is critical? Contact us. We would be happy to share more about the possibilities Exentis additive screen printing has to offer.
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