Final Report Summary - MAC-RTM (Microwave Assisted Curing for Resin Transfer Moulding)
Executive Summary:
MAC-RTM project has been focused on the development of a highly innovative alternative microwave assisted curing (MAC) technology for thermoset materials with improved flexibility and time production compared with current curing technologies, to produce high-tech products with high added value.
Specific parts with complex 3D shape representing a huge market for RTM processing SMEs have been selected by end-users and their requirements have been taken into consideration.
Selection and modification of suitable mould material in terms of transparency to microwave radiation, and selection of microwave-absorbent additives and resins (polyester, vinylester and epoxy) for the parts together with the evaluation of the interaction of these materials with microwaves have been carried out.
Simulation of the curing process including heating by microwaves and exothermic reaction has been developed. Experimental material data for the curing simulation were derived from dielectric and DSC measurements. The simulation was validated by comparison of the predictions with the temperature distribution of the part.
A lab scale unit was designed and built with the selected antenna structure and mw sensor for experimental process development.
Mould design and building has been performed for different parts for RTM and RTM-Light processes. An online measurement of the process parameters for the demonstrator unit was evaluated. A calibration of the sensors to be used in the production of the demonstration parts has been carried out in order to assure information on high level curing. The filling system has been developed and checked. As a result, an industrial production scale unit for the MAC RTM process has been obtained.
Environmental and safety criteria for the new processes, fulfilling all standards and legislation in force, were defined. From trials, it can be concluded that a reduction of around 85 % in styrene emissions is obtained with MAC-RTM technology compared with open mould process.
Microwave equipment can be considered cost-effective if it is compared with costs of oven used by conventional heating curing of RTM epoxy parts. An epoxy parts production improvement due to the use of MAC-RTM process has been obtained, counting for 3.5 times compared to conventional heating process.
From trials with industrial production scale unit, some conclusions arose:
• Fast and homogenous heating along microwave heating has been achieved by MAC-RTM technology.
• A reduction of 40% is achieved in the energy consumption compared to conventional heating of epoxy resin.
• An IR camera system allows processing of more complex parts
• DC curing sensors are useful to follow degree of cure in real time.
• An important reduction in curing time is obtained for HTG 200/205 composites, 2 hours by microwaves compared with 16 hours of samples prepared by conventional curing.
• Parts with a degree of cure close to 100 % can be obtained by MAC-RTM technology
• Mechanical properties of composite produced using both technologies, microwave and conventional heating, are comparable.
Project RTD results have been identified by all the partners, reviewed and agreed by the consortium. The final results are promising in terms of reduction on time production, comparable properties than conventional heating for RTM process.
Project Context and Objectives:
MAC-RTM project aims to develop an alternative microwave-assisted curing (MAC) technology for thermoset materials (polyester, vinylester and epoxy resins) with improved flexibility and cost and energy effective compared with current curing technologies. The MAC technology has been developed and adapted to the Resin Transfer Moulding (RTM) and RTM-Light industries for composites production. The MAC-RTM technology has been optimised through simulation of the microwave-resin interaction; and required technological improvements have been assessed and developed, such as microwave radiation transparent moulds, improved microwave radiation absorption resins and electrically antenna systems. Curing control and sensor systems as well as accurate process simulation techniques have been developed to guarantee a cost-efficient, controlled and reproducible curing process.
The developments in the MAC-RTM project have allowed the adaptation of the RTM and RTM-light processes for medium volume components production with the following advantages:
• Reducing the production cycle time in 40%, hence an increase in the productivity and costs efficiency;
• Decreasing energy consumption compared to the traditional process
• Lower styrene emissions (nearly to 90 % reduction compared to open mould processes regarding to one of the case studies identified)
• Ensure the degree of curing to nearly 100%
• Material saving as the pieces has no need to be over-dimensioned due to 100% crosslink.
Two parts have been defined and designed, and they have been manufactured and tested, in order to demonstrate that the proposed technology allows the fabrication of composite parts with similar properties than parts obtained using conventional RTM and RTM-light processes, using a faster, more cost-effective and more environmentally friendly production process thanks to MAC-RTM technology.
An integrated scalable unit has been developed and assembled as an industrial production scale unit for the MAC RTM process. Research and validation of the integration parameters with respect to the different components (mould, resin, microwave generators, antenna...) has been carried out by trials with this demonstrator. A determination of the process parameters concerning parts curing, time constants and production conditions has been taken into consideration. Different details of the process automation have been checked (microwave power, temperature …).
Main objectives of the project are summarized in the table below. WPs to which the work is related have been also detailed. Project partners consider that all project objectives have been successfully achieved.
Objectives of the project:
Identification of the 2 model parts (RTM and RTM-Light), considering the end-user requirements and specifications
Identification and monitoring of the success indicators as part of the continuous assessment along the progress of the project and to allow the identification and implementation of the corrective action and contingency plans when appropriate
Selection of the most functional susceptors and microwave absorbing groups in resin components
Selection of the most suitable materials for the mould
Specifications of new antenna structure
Homogeneity of the microwave electromagnetic field and mathematical model for curing process simulation
Homogeneity of the heating over a test samples less than 10ºC along the geometry
Microwave unit on lab-scale development
Mould Design and building including microwave antenna system and sensors for the on-line measure of process parameters
Design and building of microwave antenna structures
Assess environmental, safety and economic viability of the new process and new materials developed in MAC-RTM project
The project website has been created and contents have been uploaded
All partners have carried out at least one dissemination activity during the first project period
Plan for the Use and Dissemination of the Foreground (PUDF) has been prepared and submitted at the end of the project
Project Results:
The main scientific and technological results achieved are detailed in next points:
• Two parts have been selected and designed. Main requirements have been defined by end-users for RTM and RTM- Light
• Resins and microwave susceptors have been assessed taking into account microwave curing purpose. Selected resins and additives for the part have been characterized
• Based on first results, selection and recommendations for mould materials were defined
• Modular antenna design for homogeneous heating and electromagnetic field simulation has been carried out.
• Mathematical model for curing process has been defined.
• Concept for sensor system integrated in the antennas, providing local information about curing state and temperature has been evaluated and implemented.
• Mould design and microwave antennas have been designed and implemented.
• Moulds adapted to microwave curing have been built and tested, showing good results.
• A demonstrator of MAC-RTM technology has been developed to cure composites by microwave and the integration of the different components has been validated (mould, resin, microwave generators, antenna...)
• The definition of environmental and safety criteria for the new process, fulfilling all standards and legislation in force has been completed and some recommendations have been provided.
• A Plan for the Use and Dissemination has been completed with the definition of the potential project results by all the partners.
• The project web site was active since the early stages of the project. It has also been an efficient instrument to disseminate the project. A project video has been included in it.
• Dissemination activities have been carried out by the partners. A flyer was used during fairs and conferences in order to make the project known into different areas in relation to the different partners’ business.
• At the end of the project, partners have designed an Exploitation Agreement for project results
This information is presented below more detail and on a WP basis:
WP1: DEVELOPMENT AND MODIFICATION OF NATURAL FIBRES
- OBJECTIVES
• Specification of a model part with complex 3D shape representing a huge market for RTM processing SMEs and showing the limits of the new microwave enhanced RTM process
• Identify the necessary indicators to carry out a continuous assessment along the progress of the project and to allow the corrective actions and contingency plans identification and implementation when appropriate
WORK DONE
End users (XUQUER and SCHMUHL) defined specific parts to be produced by RTM – Light and RTM in MAC-RTM project.
XUQUER is also interested in replace the actual process of this part, hand lay-up by RTM-Light in order to obtain a better quality part and a reduction in styrene emissions during the processing.
Dimensions, details and design to adapt part to new process with microwave curing were detailed in D1.1.
Success indicators identified during the first month of the project, were assessed for each WP taking into account the technical risks of the work to be developed in each WP.
FINAL RESULTS
• Two parts are selected by end-users:
─ XUQUER: small engine bonnet
─ SCHMUHL: active component of an electrical engine part
• Main requirements defined by end-users has taken into consideration, among others, replacement of current process, hand lay-up by RTM – Light (XUQUER)
• Master model of selected parts were prepared
• Assessment of success indicators along the project: the revision of the success indicators was carried out in the technical meetings of the consortium.
• Some contingency plans have been proposed in case any deviation
WP2: MATERIAL DEVELOPMENT AND CHARACTERIZATION
OBJECTIVES
The main objectives of this work package are the selection and modification of suitable mould material in terms of transparency to microwave radiation, and selection of microwave-absorbent additives and resins for the part and evaluate interaction with microwaves.
WORK DONE
• Definition of requirements for tool material
• Selection of microwave absorbing additives and resins
• Selection of mould materials
• Characterisation of developed materials
FINAL RESULTS
• Resins and susceptors for the part has been evaluated and selected for polyester, vinylester and epoxy resins
• Resins and other materials for the mould have also been evaluated and selected
• Mechanical and physical properties have been evaluated for the resins cured by microwave and obtained results are similar to this type of resins fully cured by conventional heating.
• Further trials of polyester and epoxy resin curing by microwave radiation have been developed in next workpackages in order to evaluate influence of processing parameters.
WP3: MICROWAVE SYSTEM
OBJECTIVES
The main objective of this work package has been the development of a microwave technology adapted to the RTM process based on numerical simulation and experimental proof in a small test unit.
WORK DONE
Several concepts for the microwave antenna structures for homogeneous heating have been assessed taking into account requirements of RTM process.
The electromagnetic field generated by several microwave antenna structures has been simulated inside the mould. A mathematical model for the simulation of the complete curing process including microwave heating and exothermic chemical reaction has been developed.
A lab scale unit was designed and built with the selected antenna structure and microwave sensor for experimental process development.
The signal of the DC curing sensor was recorded and evaluated separately by an “Optimold” control box and labtop computer
Several microwave antennas have been combined to an array of antennas with an overlap of their field distribution at the border between the antennas.
Simulation of the curing process including heating by microwaves and exothermic reaction has been developed. Experimental material data for the curing simulation were derived from dielectric and DSC measurements
The simulation was validated by comparison of the predictions with the temperature distribution of the part.
FINAL RESULTS
• A lab scale unit was designed and built with the selected antenna structure and mw sensor for experimental process development.
• It is demonstrated that DC curing sensor works without disturbance (or destruction) by the microwave radiation.
• With the selected array of antennas a heating homogeneity (a maximum of 10 ºC) is achieved along the part
• To proof the homogeneity of temperature distribution and curing effect a detailed data analysis along a line diagonal through the part has been performed
• With the developed antenna system, the chosen resin system with optimum properties for a microwave curing process and with the derived process parameters by modeling, we reached the necessary homogeneity of microwave heating effect, temperature and curing.
WP4: EQUIPMENT SET – UP AND AUTOMATION
OBJECTIVE
The main objective of this work package has been to build a lab-scale unit with a polymer mould for RTM, suitable microwave antennas and an integrated sensor system to measure reflected power and the curing state.
WORK DONE
Mould concept adapted to microwave curing was defined as a first step in this workpackage. The building of the moulds has been based on the findings regarding the design and the most suitable materials for the moulds, which have been evaluated in WP1 and WP2. Developed microwave antenna structure has also been taken into consideration in order to build the mould.
An online measurement of the process parameters for the demonstrator unit was evaluated. The main features of the measurement system have been the online measurement of reflected microwave power by a directional coupler, online measurement of temperature by an IR-sensor and an online DC curing measurement.
A calibration of the sensors has been carried out to use in the production of the demonstration parts to assure information on high level curing. The calibration procedure includes specific trials with the curing resin at different temperatures, DSC tests for the cure evaluation of the samples and calculations for the determination of the parametric model.
For the system control of the demonstrator unit also the “Daisylab” was selected.
A filling control system was prepared to control the injection of the resin by manual, timer and capacitive sensor.
Designs for the microwave system including the sensors for microwave parameters have been prepared. After test runs with a small lab scale test unit (WP3) the appropriate number of antennas have been built and integrated with the complete system.
The development and assembly of an industrial production scale unit for the MAC RTM process was carried out in this WP
FINAL RESULTS
• Mould design and building has performed.
• DC curing sensors were useful to measure the change of electric conductivity/resistivity to our system.
• Optimold calibration procedure was developed and Tg-prediction in real-time can be done.
• As a result, an industrial production scale unit for the MAC RTM process is obtained
• The filling system has been checked with a standard RTM mould
WP5: SUSTAINABILITY, SAFETY AND ECONOMIC
OBJECTIVES
• Evaluation of safety aspects on the new process with the new materials
• Assess environmental performance of the new process with the new materials
• Evaluation the economic viability of the new process
WORK DONE
The most important safety and environmental aspects have been studied: emissions, waste, noise, radiation. electromagnetic field and ergonomic, among others.
Styrene emissions measurements have been carried out during process and comparative values are obtained in the pilot plant for different technologies.
Related legislation and the most important requirements have been also identified.
Preventive criteria about microwave system and different action have been pointed out in order to reduce the microwave effect.
The noise has been analyzed in order to compare process, microwave and conventional curing.
In order to define Best Practice Codes related to environmental and safety issues for new process and products some surveys were prepared and results were evaluated.
Cost calculation for the developed MAC-RTM process has been obtained as a result of the data gathered throughout the project. The costs are divided into the investment for the microwave system with sensor/control unit, which is due for payment once – and the operational costs for a production with the new system – including the costs for typical molds, the labour (production), material (for parts) and machine scheduling.
FINAL RESULTS
• Environmental criteria for the new processes, fulfilling all standards and legislation in force were defined.
• Safety criteria for the new processes, fulfilling all standards and legislation in force were also defined.
• Surveys information obtained from partners has been compiled and analyzed and some recommendations have been defined.
• Some experimental trials have been carried in order to evaluate styrene emission and noise
• A reduction of around 85 % in styrene emissions is obtained with MAC-RTM technology compared with open mould
• Equivalent noises are obtained for microwave and conventional heating.
• Microwave equipment can be considered cost-effective if it is compared with costs of oven used by conventional heating curing, nowadays used in curing of RTM epoxy parts
• An epoxy parts production improvement due to the use of MAC-RTM process is obtained, 3.5 times compared to conventional heating process.
WP6: PROCESS DEVELOPMENT
OBJECTIVES
• Integrate information and data from the previous work packages
• Produce demonstrators for verification of the microwave assisted RTM process development
• Test operation of demonstrators
• Compare thermal and mechanical properties of conventional cured composites and microwave cured composites
• Benchmark simulation models
WORK DONE
All components for the microwave curing process and the data collected in previous workpackages were brought together and were evaluated regarding useful and possible operational principles.: Materials, Moulds, Microwave system, Filling system
In a series of trials with variation of microwave power applied, set temperature and duration of microwave heating for the resins systems suitable process parameters were identified to reach a degree of cure > 90% for polyester respectively >95% for epoxy resin.
The temperature control with an IR-pyrometer sensor measuring on the surface of the mould was validated and compared to a measurement in the mould with a flouroptical sensor. An additional IR-camera system was used for visualisation and was integrated in the control loop for the microwave power. The DC curing sensor system of Synthesites was tested and validated delivering a resistance signal corresponding to the degree of cure. Different parameters involved in the injection process: air, trap, flow of the resin, pressure, were controlled in order to optimise the filling system.
Different trials were carried out with MAC-RTM demonstrator, in order to manufacture parts with XUQUER´s mould and SCHUHL’s mould to validate results for the selected materials and define processing conditions.
A characterization of optimized composites cured by microwave was performed and a comparison to traditional processes cured by conventional processes was carried out.
FINAL RESULTS
• Fast and homogenous heating along microwave heating was achieved by MAC-RTM technology.
• A reduction of 40 % is achieved in the energy consumption compared to conventional heating of epoxy resin.
• IR measurement on top of the mould was validated as sufficient for the MAC RTM process.
• An additional IR camera system allows processing of more complex parts e.g. the cyclic structure of Schmuhl’s mould.
• DC sensors curing are useful to follow degree of cure in real time.
• An important reduction in curing time is obtained for HTG 200/205 composites, 2 hours by microwaves compared to 16 hours of samples prepared by conventional curing.
• Parts with a degree of cure close to 100 % can be obtained by MAC-RTM technology
• Mechanical properties of composite produced with both technologies, microwave and conventional heating, are comparable.
WP7: DISSEMINATION, EXPLOITATION AND TRAINING
OBJECTIVES
• To establish suitable protection and exploitation mechanisms of the project´s results
• To efficiently disseminate the project´s results within the EU, both for SMEs and wider audiences.
• To improve the skills of the SEMs proposers in order to ensure efficient technology transfer
WORK DONE
Plan for the use and dissemination of the foreground has been carried out along the whole project duration, including the conditions for access to the Background at the different stages of the project implementation.
Dissemination material and activities of the RTD results have been prepared and carried out focused on the general audience and in order to increase the awareness about the project on potential stakeholders.
Exploitable Results of RTD have been agreed by the consortium
Training activities have been carried out. A best practice guideline has been prepared at the end of the project to ensure that the training can be performed systematically.
FINAL RESULTS
Plan for the use and dissemination of the foreground (PUDF) has been defined. Final version of the exploitation strategy of the results has been summarized in the PUDF.
The PUDF detail the plans for using the SMEs results (Foreground) either through further development and commercial exploitation or through research including the conditions for the access to the Background.
The PUDF include an update on the dissemination programme. It has been a living document and has been updated throughout the project.
The project web site (www.macrtm.eu) active since the early stages of the project has also been an efficient instrument to disseminate the project.
Some organizations have contacted the coordinator to express their interest on the project results.
Dissemination materials (poster, flyers, general presentation, videoclip, among others) have prepared and used in different events. Main dissemination activities:
o JEC Europe 12 and 13
o JEC Asia 13 and JEC USA 13
o Article in Reinforced Plastics
Potential project RTD results have been identified by all the partners, reviewed and agreed by the consortium
Different trial technical sessions were organized in which SMEs took part: October 2012, December 2012, April 2013, June 2013 and September 2013.
In these technical sessions SMEs worked directly on the new technology implementation. A final training activity about “How to use the project developed technologies: the Best Practices Guidelines” has been carried in 23rd October 2013 at ICT facilities. All partners attended to it, in order to ensure the efficient technology transfer of the MAC-RTM project developments and to enable the industry partners to design appropriate microwave antennae systems and acquire the tools and knowledge to use the MAC-RTM technology.
A best practice guideline has been prepared at the end of the project to ensure that the training can be performed systematically.
WP8: MANAGEMENT
• To optimize the resources and to ensure that all EC requirements are met
• Define, provide and set-up the necessary communication procedures
• Continuous assessment of project development
• Administrative and financial project management
WORK DONE
• Management of internal project communication including project communication tools
• Involvement of partners in project management and functioning of the Decision making process
• Report to the Commission on work done and results obtained
• Report to the Commission on costs incurred by partners for the development of work
• Management of issues arisen during project development
FINAL RESULTS
• Partnership decided to add Guidelines for the modeling for the SMEs” as part of Deliverable D7.4 and allocated tasks for this development
• Internal part of the project web site has been updated with all relevant information for partners (Agendas and minutes of Technical, General Assembly and Exploitation Board meetings, Deliverables, project products and news…). Communication among partners between meetings have functioned smoothly using email distribution lists and conference calls
• Partners have actively participated in the decision making bodies of the project. The following meetings have been held (attendance to technical meeting was limited to those partners directly involved in the related tasks):
o 22/11/2011. Kick off meeting in Valencia (Spain)
o 16/02/2012. General Assembly meeting in Madrid (Spain)
o 28/03/2013. Technical meeting in Paris (France)
o 17/07/2012. General Assembly in Rotterdam (Netherlands)
o 05/10/2012. Technical meeting in ICT facilities (Germany)
o 16/10/2012. Review meeting in Brussels
o 18/12/2012. Technical meeting in Valencia (Spain)
o 28/01/2013. General Assembly meeting in Valencia (Spain)
o 03 and 04/04/2013. Technical meeting in ICT facilities (Germany)
o 04 and 05/06/2013. Technical meeting in ICT facilities (Germany)
o 23 and 24/10/2013. Technical meeting and final meeting in ICT facilities (Germany)
Communication among partners between meetings have included the following conference calls:18/01/2012, 16/05/2012, 20/09/2012, 06/11/2012, 11/01/2013, 08/05/2013, 12/07/2013, 13/09/2013 and 07/10/2013.
• Financial reports (including Form C from all partners) have been submitted to the Commission for P1 and P2. Internal economic control was carried out in January 2013
Potential Impact:
MAC-RTM project has integrated microwave technology into a close mould system and new resin systems with the following final results, among others:
microwave antenna system integrated with the demonstrator and useful with different moulds and geometries.
RTM moulds adapted to microwave curing requirements
Obtainment of an homogeneous heating of the parts
control and automation of filling and curing of parts
improvement of productivity
obtainment of a degree of polymerisation to nearly 100% with microwave curing, without the need of post-curing
The MAC – RTM project has contributed to enhance the competitiveness of the European SMEs in the global market with the development of an integrated system that is technically innovative, environmentally friendly, and economically viable.
MAC-RTM will open up great market opportunities for the composites industry in Europe, a sector mainly composed by SMEs which are focused on manual and traditional processes like hand lay-up and spray-up. MAC-RTM may enable an important change in the composites sector. Some of the benefits for European SMEs by using MAC-RTM technology are described as follows:
• Use of alternative curing technology: An alternative curing technology based on the use of microwave radiation has been developed and optimised for RTM processing technology. The goal of such alternative curing method has been to improve the heat transfer and heat control during curing stage of the RTM process. Such a curing method has allowed the obtainment of homogeneous temperature control over the complete composite cross section in the RTM mould thereby allowing RTM process to be used effectively for curing thin as well as thicker parts.
• Adoption of RTM process as an energy efficient and economical process: Microwave assisted moulds for curing of RTM components have been developed and their use has been targeted in order to reduce production cycle time in 40% due to the reduction of polymerisation time, and reducing energy consumption during RTM processing, thereby increasing the productivity and hence the cost-efficiency for the SMEs.
• Improved RTM process sustainability: ability to produce different thickness with homogeneous degree of curing, reduced internal stresses and improved product quality compared with conventional RTM process due to inhomogeneous degree and internal stresses problems, facilitating the approach of the RTM process to the SMEs.
The main efforts have been focused on introducing the technology into the companies that are going to produce and use the innovative composite materials as end-users. An evaluation was made by MAC-RTM partners of the potential of each of the exploitable results. Exploitation results of the SME are defined as follows:
• PR1: Mould material and design
• PR2: Design of microwave antenna system
• PR3: Resins for microwave assisted RTM technology
• PR4: Control and automation system for the filling – sensors design
PR5: On-line sensors for the curing parameters measurement
List of Websites:
www.macrtm.eu
Coordinator:
AIMPLAS - Instituto Tecnológico del Plástico
C/ Gustave Eiffel, 4 (València Parc Tecnològic)
46980 - PATERNA (Valencia) – SPAIN
Tlf. (+34) 96 136 60 40
Email: macrtm@aimplas.es
