Community Research and Development Information Service - CORDIS

H2020

EFFICOMP Report Summary

Project ID: 690802
Funded under: H2020-EU.3.4.

Periodic Reporting for period 1 - EFFICOMP (Efficient Composite parts manufacturing)

Reporting period: 2016-04-01 to 2017-09-30

Summary of the context and overall objectives of the project

Today the citizen mobility inside each continent and between the major continents (America-Europe-Asia) is a basic necessity to develop commercial, cooperative and cultural exchanges. The consequence of this growing demand in the world is a large increase of the number of new aircraft to enter in service in the coming years. In 2014 Airbus has delivered 629 aircraft in the world and acquired 1456 new aircraft net order. In 2014, Boeing has delivered around 723 aircraft and acquired 1432 new aircraft net order. Since more than 10 years, the net new order aircraft per year is significantly higher than the aircraft delivered per year. This is due to the limiting capacity in production of new aircraft per year. The scheduled ramp up in aircraft production in the coming years will impose to have new efficient parts production and especially for composite parts that have today a long process time due mainly to the intensive utilization of autoclave process to manufacture composite parts. The main objective of EFFICOMP is to develop efficient processes for the fast-track cost-effective composite aircraft of the future. For new single aisle aircraft with a cadence objective of about 60 aircrafts per month, we will have to propose new efficient processes capable of high rate production at low cost to avoid huge investment in many autoclaves.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Material cost reduction :
New low cost materials :
The material acquisition has been reduced by using UD-prepreg material which is made of carbon fibre heavy tows (25k-50K) instead of 3-12K which is normally used for aerospace applications.
An automated ply deposition process for part forming with OoA UD-prepreg-tapes and out of autoclave curing has been developed to reduce the processing time, waste and energy consumption.

New heating solutions :
Resistive heating :
For the new Resistive heating process based on Joule effect, we introduced current in the carbon fibre to generate the heat directly inside the material. Heating rate of 30°C/min has been technically validated. We are capable to save about 50% of the global curing time. Based on specific tests we have validated the importance of current introduction point in the part on the temperature homogeneity in the part. We have obtained a good temperature homogeneity through the length of the sample in all the tests performed. The maximum size of composite panel cured with this technology was a panel of 500x300 mm. The maximum thickness of composite panel we have cured with this technology is a 80 plies quasi isotropic lay up (about 15 mm)

Hybrid heating :
In order to reduce cycle times and energy consumption during CFRP structure manufacturing in and out of autoclave adaptive, convection based hybrid heating and cooling concepts were examined. For this an invar steel tool was tempered three times with different methods (1. standard autoclave tempering process; 2. water tempering out of autoclave; 3. hybrid tempering, which combine water and autoclave tempering at the same time). The best results were reached with the hybrid tempering. Compared to the standard autoclave process, the cycle times to heat up and cool down the tool were decreased of about 10 hours. Process 2 and 3 provides the same results. However, in autoclave there is the possibility to pressurize the CFRP structure production, which leads to much better component properties.

New concepts in the mould environment :
Reusable bagging :
To reduce the preparation time for the cure process, reusable bagging material was investigated. Heating devices were integrated into the membrane to allow a more even temperature distribution over the laminate thickness during curing. The cure mould concept is adapted to the reusable membrane concept so that no vacuum lines need to be attached and detached between manufacturing cycles.

Permanent release agent :
It was investigates possibilities to enhance the functionality of the moulds release properties over several manufacturing cycles, without the need of recoating. Therefore a release system testing rig was developed to test different combinations of permanent mould surfaces and semi-permanent release agents.

Low cost tooling :
Alternative forming tool materials like graphite, ceramic as well as CFRP should be examined. The challenge is to provide the required geometrical accuracy and reliability especially with increasing component complexity. In order to be able to evaluate the suitability of the materials, various tests are carried out and analysed.

Composite part forming and joining
Thermoset semi cures prepreg Forming :
Two main topics have been addressed.
Automatic fibre placement of semi cured prepreg on curved tool. Parts of 300x600 mm² have been produced with different curing ratio of the prepreg. Parts with different thicknesses have been manufactured (8 plies 2 mm and 40 plies 10 mm). different speed deposition have been tested. The final porosity level obtained after the final post cure on these panels is low and acceptable.
Flat panels with thickness variation in the panel have been manufactured to validate the forming capability of U shapes. Different forming speed and energy input have been tested and the final quality seems to be better with the faster process.

Thermoset prepreg forming :
Thermoset part forming of out of autoclave UD prepreg:
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Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Contribution to the state of the art:

AGI :
With the technologies developed by AGI, resistive curing process, automatic laydown deposition of semi cured prepreg and forming of semi cured laminates, AGI is establishing the state of the art for these new technologies. (patented before EFFICOMP project deposition)

DLR :
The use of fluid-heated mould for composite application is not very common yet and the combination of two or more heating technologies can rarely be found in literature. The assessment of the combined autoclave and fluid heating will add knowledge to the state of the art.

USTUTT :
Investigation of OoA-prepreg curing parameters to meet quality standards of standard autoclave curing processes
Validation of APP-process to meet aerospace quality requirements while processing low cost heavy tow OoA prepreg material directly into final part geometry.


TUD :
State of the art on joining techniques for composite structures based on welding through a thermoplastic interface is currently being expanded as a result of our activities in EFFICOMP. This is a novel area and hence our activities have a high impact contribution to it.

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