very soft TPU powder, SLS components made of TPU, shore hardness 55, 3D printing with TPU
Very soft TPU powder; Rubber-elastic 3D components, shore hardness 55
Thanks to an innovative manufacturing process and a new type of after-treatment of the SLS powder, we are able to provide very soft TPU powder for the SLS process. Compared to the plastic powders from competitors, our TPU SLS powder offers the following key advantages:
- Spherical particle shape
- Narrow particle size distribution, D[V, 90] = 96 µm
- Optimized pourability
- No smoke development during processing
- 100 % reusable
- Very soft material behavior (Shore hardness A 55)
- Pleasant feel
- Elongation at break of at least 450 %
- Resistant to hydrolysis
- UV-resistant
- White or black components possible
The soft thermoplastic polyurethane powder for the SLS process has spherical particle shapes and therefore the best possible flowability. Unlike many other SLS TPU powders, there is no smoke development during processing, which could affect the system. This means that no modifications or costly cleaning of existing SLS systems are necessary. Since the material does not age significantly thermally, our TPU SLS powder can be reused up to 100 %, which brings a significant economic and ecological advantage. The very soft TPU SLS material offers a very pleasant feel and is therefore ideal for applications in the orthopedic sector, for bracelets or production aids. The rubber-like properties with an elongation at break of at least 450 % are comparable to injection-molded TPU components. In addition, the SLS TPU component is hydrolysis-free and therefore washable up to 60° and UV-resistant. For use in low-performance SLS systems, we offer the TPU with optimized absorption, in black.
3D printing with TPU: Soft TPU for bracelets, shoe soles, etc., here as an elastic chain mail with a pleasant feel.
Close-up of spherical TPU powder particles compared to a human hair.
Polyamide 12 as an established material for the SLS process
While the spherical polyamide 12 powder (PA12) has already established itself for selective laser sintering (LS, SLS), more and more new and alternative materials for SLS are currently coming onto the market. In the course of a chemical precipitation process, polyamide 12 polymerizes into bean-like particles. With a particle size distribution of D[V, 90] = 88 µm, PA12 is particularly suitable for a layered, additive manufacturing process with a layer thickness of 100 µm. The disadvantage of PA12 is the thermo-oxidative aging of the plastic. For this reason, this powder usually has to be refreshed to 50 wt-%.
Complex PA12 component as a lampshade with complex design elements [Designed by Roman Rainer Schmid, www.romanreiner.com]
Close-up of PA12 SLS powder with a typical potato or bean-like particle shape.
What about rubber-elastic materials for the SLS process?
Thermoplastic polyurethanes (TPU's) represent a very interesting material group of thermoplastics, which when injection molded have rubber-like properties. Depending on their chemical orientation, TPU'S can vary between very hard and very soft. Mainly hard TPU types with a Shore A hardness of 90 have become established for processing in the SLS. Soft TPU SLS powder was previously not possible to produce.
Example of a hard TPU SLS powder: Application as a finely structured shoe sole/midsole from 3D printing with TPU.
TPU grades with a high Shore A hardness (such as 80-90) are well suited for thin structures that allow “soft” kinematics due to their fine geometry. SLS components made of TPU with high shore hardness are already widely used for shoe soles, midsoles, seals and the like. However, if the available space or a soft feel is desired, hard TPU's are out of the question.
Why not a very soft TPU powder for selective laser sintering up to now?
In conventional powder production, the base material needs to have a certain rigidity and hardness in order to form a defined particle shape. The TPU is heavily cooled using liquid nitrogen in order to grind it. In this way, it is possible to produce elastomer powder from TPU with a Shore hardness of approx. 80 and higher, with the powder particles having a very angular shape. With softer TPU (eg Shore hardness 55) such grinding was not previously possible.
Schematic representation of the powder particle shape as it occurs during the cryogenic grinding of TPU with a high Shore hardness.
Schematic representation of the powder particle shape of our soft TPU SLS powder. The spherical shape enables the best flow and powder application properties (Shore hardness 55). The spherical shape enables the best flow and powder application properties in the SLS process.
Very soft TPU powder, what is possible with it?
The SLS process enables the production of very complex structures without the need for support structures. This means that not only interesting design elements, but also entire textile structures are possible in 3D printing with TPU. At the same time, an SLS component made of soft TPU also feels very comfortable on the skin. Orthopedic insoles, shoe soles and jewelry are just as possible as the 3D production of technical dampers, TPU seals and other SLS components made of TPU.
Possible SLS components in 3D printing with TPU:
- 3D structured TPU shoe soles
- Complex 3D midsoles made of TPU
- Orthopedic individual TPU insoles
- TPU wristbands for production aids
- TPU damper elements
- System feet made of TPU
- Textiles made of TPU mesh
We research and develop the implementation of the process capability of soft TPU's for the SLS process
Since each material in the SLS process requires a very fine adjustment of parameters in terms of laser power, exposure parameters, process temperature and much more, we research and develop suitable process parameters and optimal powder compositions in order to make the soft TPU material optimally accessible for the selective laser sintering process.
We would be happy to examine the possibilities with you to develop a suitable material for your SLS system, so that you too can manufacture SLS components from very soft TPU.
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