Additive Manufacturing Becomes 20 Times Faster
In order to combine the benefits of additive and subtractive manufacturing methods, the Institute of Plastics Processing (IKV) in Aachen has developed and successfully implemented a hybrid manufacturing cell.
The central components of the hybrid manufacturing cell is the positioning system in the form of a modern 6-axis robot, which is equipped with a standardised tool change system thus ensuring maximum automation and flexibility. In the method developed by IKV, a screw-based plasticising unit operated with plastic granulate is used in additive manufacturing steps. Compared to filament-based manufacturing technologies, this allows the processing of reinforced plastic compounds and high throughputs at the same time. In addition to increasing the throughput, this results in a significant cost reduction due to the use of the more cost-effective granulate.
The costly manufacturing of precise filaments is typically 10-30 times more expensive than the method with plastic granulate described above.
In the hybrid manufacturing cell, gripper systems or milling tools can be coupled with the positioning system as needed. This allows other processes such as the provision of depositor shapes for the integration of additional functions or subtractive post-processing to maintain dimensional accuracy to be realised.
Processes where components are built in layers on the basis of 3D volume models are defined as additive or generative manufacturing methods. These methods are often also referred to as 3D printing. Subtractive manufacturing, by contrast, is where a component is made by subtracting material. So, for example, a smaller component is created from a material blank by way of grinding, drilling or milling.
Hybrid manufacturing cell at IKV in the 73-minute manufacture of a 90 cm high rotor wing (left) and resulting component properties in the example of microscopy recordings of the component surface (right).
New Possibilities in Additve Manufacturing
The processing of highly reinforced plastic compounds opens up new possibilities in additive manufacturing and is a core competence of AKRO-PLASTIC GmbH in Niederzissen. The carbon fibre reinforced AKROMID® B3 ICF 30 9 AM (7451) is successfully used by the Institute of Plastics Processing (IKV) in Aachen in this newly developed melt deposition modelling process (MDM process).
On the basis of improved thermal conductivity of the carbon fibre reinforced compound, the associated faster cooling speeds and the low lot tolerance for high-fill plastics, a stable manufacturing process with high production speeds has been implemented which results in outstanding mechanical properties. In order to improve the dosing and the feeding rate, AKROMID® is also supplied in granulate sizes below 1 mm in diameter which allows the use of finer dosing systems with even shorter holding times.
Resins ICF Compound.
Watch the Video!
In this video the process of additive manufacturing is applied. The video was recorded at the Hannover Fair 2018.
Nicolai Lammert - Institute of Plastics Processing in Aachen
Nicolai Lammert, who is at the head of the “Additive manufacturing” team at the Institute of Plastics Processing in Aachen and who is responsible for the development and implementation of the hybrid manufacturing cell, is very positive about the new method: “With the help of our manufacturing technology and the 30 % carbon fibre reinforced polyamide 6, we are able to realise ultimate stress levels of 148 MPa on the manufacturing level (XY direction) and 40 MPa in the manufacturing direction (Z direction) on the component.
The properties in the Z direction correspond to 85 % of the mechanical properties of pure PA 6 basic thermoplastics. The anisotropy material properties of the compound, and the high mechanical properties in the manufacturing direction, can now be used specifically for load path adjustment of mechanical properties in the subsequent component due to the flexible mobility of the industrial robot. At a discharge capacity of 6 g/min currently, it is also possible to increase the production speed in comparison to the FLM-based manufacturing method by a factor of 20. We also see significant potential for more here.”
Dr. Jan Dormanns - SMP Deutschland GmbH
Due to the significantly increased production speed using a series production-tested technical thermoplastic, the hybrid manufacturing cell is not limited to the production of prototypes, but opens up new possibilities with regard to rapid manufacturing.
An exemplary application for such large-sized components is the concept study of a highly-integrative bionic support structure for instrument panels for the automotive supplier SMP Deutschland GmbH based in Bötzingen. Dr. Jan Dormanns, Project Manager in pre-development, explains: “In this bionic structure, both cross beams and air ducts as well as connectors for airbags, steering columns, displays and cladding parts are combined into one supporting unit.
In an overall concept where few tools are used and with investment savings of over 1.5 m Euros, rapid manufacturing could allow economical manufacture of such structures for small series. The MDM method of the IKV and the compounds of AKRO-PLASTIC GmbH make a great contribution to the future industrial feasibility of such concepts.”
Potential application for future rapid manufacturing: Concept study of a bionic support structure for instrument panels of SMP Germany GmbH.
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