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ScraPping cArbon Reinforced ThermoplAstic.

Periodic Reporting for period 1 - SPARTA (ScraPping cArbon Reinforced ThermoplAstic.)

Reporting period: 2020-09-01 to 2021-08-31

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 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. But, due to the COVID situation, during this period of SPARTA the Communication and dissemination was not progressing as planned. In the first 12 months of SPARTA, the project beginning was communicated via partner homepages and a newsletter was delivered, as well as through articles in magazines and online portals aimed at specific countries and/or sectors. During this period the Intermediate Plan for Exploitation of the Results and Dissemination deliverable have been uploaded.
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 these limitations this SPARTA project proposes 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 could be obtained. This method proves to be promising 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. The tool material affects the design of the geometry of the cutter and the manufacturing process necessary for manufacturing the tool. The most common tool materials are High Speed Steel (HSS), cemented carbide (WC/Co), ceramic, diamond and cubic boron nitride (CBN). The most conventional manufacturing process for finishing these materials is grinding. However, when complex geometries have to be developed, other non-conventional technologies can be considered, such as laser ablation. As the budget to carry out this approach is quite limited, CNC 3 axes machines available in the TEKNIKER workshop will be used to develop the delamination process proposed. Nevertheless, the process will be analysed deeply so that it can be extrapolated to an industrial framework in the future.
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 labor cost of the blue collar, high equipment investment and lay-up defectology.
The solution proposed in SPARTA to overcome this great challenge is to use an existing collaborative robot located at AIMPLAS facilities. The objective is to design a tailor-made head deposition based on a “pick&place” concept (and Figure 13) with a sucker device which will enable to place each tape following the CAD pattern designed previously. This does not involve a mechanical re-design of the collaborative robot but an adaptation of the head of the existing rotot. At an industrial level, more than one collaborative robot can work together for a higher production rate getting several benefits from the automatic lay-up:
• Research for advanced materials and i4.0
• Provide accessible technology to member industries
• Automation for TP rCF material deposition
• Collaboration opportunities
• Easy to scale
Key Exploitable Results (KER) (cogido de la memoria)
• Key Exploitable results: 1.- Special cutter & tool holder
• Key Exploitable results: 2.- Grinding process parameters adapted to each End of Life Thermoplastic reinforced part.
• Key Exploitable results: 3.- Tape manage to positioning on the mould by using a collaborative robot and compression moulding process parameters
Potential Impact (cogido de la memoria)
• Expected impacts set out in the work programme, under the relevant topic: Reducing CO2 emissions, Reducing CO2 emissions (table 9 of the DoW)
• Strengthening the European competitiveness
• Enhancing innovation capacity and integration of new knowledge
• Economic impact brought by SPARTA innovations: strengthening the competitiveness and growth of companies