Fraunhofer Institute for Machine Tools and Forming TechnologyWhat is the challenge?
3D printing opens up completely new product and manufacturing approaches. However, many 3D printing processes are too expensive and too slow for industry. The key here is to produce large quantities in a short time at competitive costs. Our specially developed SEAM process is not only eight times faster than conventional 3D printing, but also enables the use of low-cost standard plastic granulate.
What solution do we have for you?
SEAM stands for Screw Extrusion Additive Manufacturing. The SEAM system consists of an extrusion-based plasticising unit for processing plastic granulate, which is combined with a Hexapod. The Hexapod - a swivelling 6-axis parallel kinematic system - is equipped with a metal build platform. The Hexapod motion system is characterised by high dynamics, low moving masses and an associated high positioning and path accuracy, making it ideal for extruder motion control. In addition to this SEAM complete system, the plasticising unit can also be integrated into other machines and systems.
The printing process is carried out by drawing the plastic granulate into the extruder and plasticizing it using a modified extrusion screw. Process speeds of up to one metre per second can be achieved. Then the resulting plastic melt is deposited on the building platform in layers. Thanks to the parallel kinematics, the build platform can be tilted in the X-, Y- and Z-axes and moved along under the nozzle of the plasticising unit in such a way that the previously programmed component shape is produced in a real 5-axis 3D printing process with virtually no support structure. The continuous depositing process enables the production of large-volume, loadable components.
For controlled printing in curves and corners as well as for position jumps without material discharge, it is necessary to control the discharge rate as a function of the web speed. Due to the very sluggish plasticising behaviour of an extruder, a volume change via the extruder speed is not sensibly possible. Therefore, an upstream unit was developed that allows a speed-dependent material discharge between 0 and 100 percent.
In the SEAM process, a free-flowing, low-cost standard plastic granulate can be processed. Compared to classic fused layer modelling (FLM) processes, where expensive filament is used, material costs can be up to 200 times lower. Wide varieties of plastics have already been tested - from thermoplastic elastomers and polypropylene to polyamide-6 with 40 percent carbon fibre (PA 6 CF).
What is now available in concrete terms?
With the SEAM process, we offer you industrial high-speed 3D printing for high-performance plastics - as a complete system based on a swivelling 6-axis parallel kinematics hexapod or as a process for integration into your machines and systems.
Which partners were involved in the development?
- Metrom GmbH
- 1A Technologies UG
