CORDIS - EU research results

ScraPping cArbon Reinforced ThermoplAstic.

Periodic Reporting for period 2 - SPARTA (ScraPping cArbon Reinforced ThermoplAstic.)

Reporting period: 2021-09-01 to 2022-10-31

Nowadays, the rapidly increasing rate on demand of use of thermoplastic (TP) composite in the aerospace market over the five next years, about 616.14 million€ in 2024, brings about the challenge of extending the lifetime of the products turning worthless scrap material into valuable raw material through recycling reused maintaining the mechanical properties. On the other hand, the air transport industry is paying a lot of attention to growing public concern about the environmental impact not only during aircraft operations, but also during production of virgin composite materials (482.0 MJ/kg energy of primary CFRP production) and end-of-life (EoL) phases. A greener design is essential to protect the environment for aircraft on-ground. This leads to manifold requirements for eco-design-operations such as the use of aeronautic recycled material for the manufacturing of the thermoplastic (TP) components. The Eco-Design initiative could contribute to a minimal use of raw materials and energies thus improving the environmental impact of the whole products life cycle and maintaining the mechanical properties of the reused scrap. However, the recycled parts coming from aeronautic or other transport devices are large and thick (> 4 mm) and their resulting scrap material is complex to be reused in conventional technologies such as compression moulding.

SPARTA project aims at designing and manufacturing a novel and eco-efficient scrapping methodology of reinforced fibre structures in order to approach the dimensions required for compression moulding manufacturing of high-quality parts producing a significant lower percentage of dust than conventional grinding technologies.

The eco-design objective will be achieved thanks to the following key drivers:

The recycling technologies for high-performance thermoplastic composites are designed to reduce the embodied energy footprint of the material. However, the recycled fibre obtained from the traditional recycling methods does not reach the appropriate mechanical properties to be reused for new aeronautical composite applications. This fact strongly suggests an opportunity to address a trade-off between energy efficiency and the quality of the product.
SPARTA is a 26-month project, structured in 3 phases.

From the technical point of view, this phase is dedicated to performing an extensive bibliographic review of the conventional recycling process of thermoplastic composites. For this assessment, environmental aspects such as energy consumption, chemical releases, outgassing, etc., will be considered to identify the challenges of the new recycling method proposed in the SPARTA project. In this regard, in the Task 2, a scrapping method will be defined and cutting tool will be designed and manufactured considering the cutting process simulation. Scrapping trials with PEKK/AS4 and PA6/GF have been carried out in Task 3 and optimization of the cutting tool has been performed. Additionally, first reprocessing trials of the scrapped-UD tapes have been started and a strategy for manufacturing of a recycled panel has been drawn. LCA data is being collected at each different process. CDR has been accomplished at the end of Task 3.

During the first year of SPARTA project have been achieved several communication and disseminations actions.
Currently, the SPARTA methodology is under development. So far, no changes from the beginning of the project regarding the SoA, expected results and potential impacts.

Beyond the state-of-the-art of recycling methods for TP CFRP
To overcome all the current recycling limitations this SPARTA project has proposed a new approach maintaining the same mechanical cutting concept but replacing the rotary movement between cutter and workpiece by a linear one. This way chips of uniform thickness are obtained. This method proves to be effective when the objective is to delaminate or get thin layers of material.
This process would be similar to what in the machining industry is known as broaching and which is characterized by the strict design of its tools. Cutting tools can be manufactured in different materials depending on the wear behaviour, chemical compatibility with the workpiece material, stability of the process, etc. As a result of the project a tool has been designed and tested and the cutting process has been developed to get the wanted thin scrap tapes that can be used in a compression moulding process. The main advantage of the SPARTA technology is the capability to process laminates in any direction so that thin tapes containing long fibres are obtained. These tapes can be cut to a specific width and length being the limit the dimensions of the input material.

Beyond the State-of the-art of solutions for CFRP UD tapes laying
In order to obtain accurate measurements of the position of the UD chopped tapes, an accurate calibration patterns and methods are needed to avoid high labour cost of the blue collar, high equipment investment and lay-up defectology.

The solution proposed in SPARTA to overcome this great challenge is to combine the use a collaborative robot to automatise the layup process and the material consolidation by compression moulding means. In this regard, a tailor-made head deposition based on a “pick&place” concept with a gripper device is designed. It will enable to place each tape according to the CAD pattern designed previously to obtain a consolidated panel in the compression moulding equipment. Finally, a fully aligned recycled panel made of long and continuous fibre unidirectional tapes is obtained.

Expected results:
The ultimate goal of the SPARTA project is to define a novel cost-efficient method for thermoplastic composite recycling and maximise the mechanical properties of the recycled performance. The following outputs have been obtained at the end of the project.
- A flexible cutting tool for thermoplastic panels delamination
- Scrapped material in unidirectional tape format under a constant wide and thickness dimension
- An automatic layup system for unidirectional tapes positioning and laminate construction.
- An optimised consolidation cycle to obtain a recycled thermoplastic panel.

Potential Impact:
• Reducing CO2 emissions
- Scrap recovery by 80%
- Reduction of energy consumption by at least 10%
- Reduction of the CO2 emissions by at least 30%
• Improving EU Competitiveness:
- Reduction of processing time by 50%
- Reduction of production cost by 15-20%
- Strengthening the European competitiveness and growth of companies
- Enhancing innovation capacity and integration of new knowledge

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