Collins Aerospace and the University of Sheffield Advanced Manufacturing Research Centre
The HVCMS (High Volume Composite Manufacturing System) project set out to answer the question of how to produce composite fuel pipes at peak production rates of 5,000 pipes per month.
Filament wound composite pipes for aerospace fluid transfer are fitted within the aircraft fuel and hydraulic systems to manage the effect of a lightning strike, while still facilitating dissipation of a static charge. Collins Aerospace has developed a robust method of joining the composite tube/pipe with various metal fittings. The composite fuel pipes and highly resistive fittings allow the precise tuning of electrical resistivity and fly on aircraft today. They are scalable and able to hold aggressive fluids at pressure within an aircraft.
The project was awarded £2.26M and was run in partnership between Collins Aerospace company and the Advanced Manufacturing Research Centre (AMRC) and ran over a three-year period, September 2014-2017.
The project objective was to mature manufacturing technologies to meet the following challenges:
• Work Package 1: Develop composite manufacturing processes and an automated and fully integrated production system able to manufacture 50,000 fuel pipes a year, achieving a TAKT of 4 minutes. These technologies needed to be transferable to higher rate programmes, such as the next generation of single-aisle aircraft, where volumes of 240,000 per year are estimated.
• Work Package 2: Develop technologies to optimise the composite filament winding process in support of the development of the HVCMS and for application where higher production rates are required.
• Work Package 3: Demonstrate manufacturing technologies for complex geometry composite fuel pipes, enabling further application of fuel pipe technology within aircraft.
Table 1: Summary of the project grant details
Table 2: Summary of the project focus areas
Work Package 1: High Volume Composite Manufacturing System
Objective: High Volume Composite Manufacturing System
The primary objective of work package one was the development and demonstration (MRL6) of a High Volume Composite Manufacturing System for Fuel Pipe technology, able to meet production rates of 50,000 per year and a 4 minute TAKT. Other target benefits from these activities were to improve yield to meet Collins Aerospace ACE Gold Standard of 500dppm and positively impact product cost. Adoption of Industry 4.0 technologies was also vital to enable the effective management and control of high volume manufacture.
A number of key technical challenges were addressed in the delivery of this work package:
- Production System Design, Collins Aerospace applied an Automotive approach to the design of the production system ensuring that it promoted single piece flow, minimising operator touch time and integrating real-time process monitoring and control within the production system.
- Design for Manufacture in support of automation, an assessment of the original qualified design was made to ensure suitability for automation. This drove a number of design configuration changes that were approved with the customer to allow for the adoption of automation.
- Filament Winding Automation, Collins Aerospace identified the control of filament winding process parameters to be a key driver in quality performance. The challenge for the project was to develop a filament winding process to achieve consistent quality performance, with real-time process monitoring and control, establishing a flexible manufacturing capability.
- Automated Resin Management & Control, Management of the resin system was identified as a key process when considering quality and product performance. Process controls were established with a resin system supplier to develop a high accuracy resin management system.
- Protective Tape Removal, one of the key automation challenges identified in the project was the removal of protective tape used in the winding and curing process. The existing process was to manually remove the tape which was a complex and time consuming task and not an option when considering a 4 minute TAKT. In collaboration with the AMRC, an analysis of various alternatives was undertaken and down-selected an innovative blasting approach as a preferred solution.
- Automated Composite Machining Cell & Non-Contact Metrology, control of machined surfaces is a critical control feature for composite to metallic joining. A key part of this project was to optimise the machining process in terms of cutting performance and swarf control.
- Integrated PAT capability for rate, alternative Product Acceptance Testing (PAT) methods, such as Helium Leak Testing, were developed to enable full rate production volumes.
- RFID Integration, Radio-frequency identification (RFID) technology was implemented to improve materials management and logistics control to meet the challenge of rate production.
- Automated process data capture, a key challenge for high volume composite manufacture is one of process monitoring and control to ensure targeted yield thresholds. Collins Aerospace worked with both equipment and IT providers for sensing technologies, real time monitory and control, linking key manufacturing data automatically to serialised part information.
Work Package 2: Filament Winding Optimisation
Collins Aerospace: CNC Filament Winding Program optimisation improved CT and process performance
Objective: Improve Filament Wet Winding Performance by 20%
A key objective for Collins Aerospace was to improve the cycle time performance of its filament winding operation to ensure that the baseline business case could be achieved. An analysis of the winding process was undertaken, identifying process bottlenecks and key opportunities for improvement. Work was undertaken with the OEM of the Filament Winders control systems, with changes to the control methodologies, and a circa 30% cycle time improvement for filament winding was established.
AMRC: Prototype Resin bath incorporating technologies to improve resin wet out
Objectives: Improved Resin Wet Out
The initial goals to deliver this work package were to bench-mark the existing Collins Aerospace production processes, setup AMRC’s filament winding cell to reproduce Collins Aerospace fuel pipe production lines, then introduce optimisation processes into manufacturing.
The AMRC focused upon improvements in the resin impregnation process to improve the repeatability of the component electrical properties and reduce the void content. Additionally, other manufacturing processes were optimised, with RFID tag placement for part identification and tracking and a release agent investigation to move away from harmful release agents.
AMRC in collaboration with Collins Aerospace looked at development of resin bath modifications to improve the following parameters:
• fibre wet out
• winding speed and overall process time
• resin usage and resin waste
• fibre volume fraction
• void content
As part of the investigation of additional ways to improve the impregnation of the resin, novel resin management and application technologies have been investigated. An SME, in collaboration with AMRC developed a demonstration resin bath integrating these technologies. The technology is now being tested in an industrial environment at Collins Aerospace.
Increased component geometry, the manufacture of pipes with bends
The main objectives of this work package were trade studies into potential processes for complex geometry tube manufacture and tooling solutions for manufacture of complex geometry pipes. Collins Aerospace and AMRC down-selected four distinct complex geometries that can easily be introduced into Collins Aerospace product portfolio. AMRC surveyed commercially available removable mandrel solutions that could withstand the manufacturing conditions, are affordable and could match high-volume demands. AMRC also studied preform winding technologies for complex fuel pipes geometries.
Several removable mandrel solutions studied by the AMRC were assessed in pre-industrial manufacturing trials, including water soluble sand and high temperature melt-out wax. AMRC submitted an overview of the implementations cost of these mandrel technologies at the end of the project.
Utilising the incumbent Filament Winding (FW) process used with Collins Aerospace, the AMRC developed and validated in a semi-industrial environment the winding programs for these 4 distinct complex geometries. AMRC manufactured industrial prototypes using FW manufacturing processes to be tested at CTG.
Figure 2: Complex geometry filament wound GFRP
Alternative fibre deposition processes were also studied in this project that are commercially well-established technologies, suitable for high volumes, low labour-highly automated, have low tooling costs, low material waste, a high level of performance tunability and process characteristics that can be engineered for specific applications. Through the HVCMS programme, AMRC working with the University of Manchester developed preforms for the 4 down-selected complex geometries. AMRC and Collins Aerospace are discussing a follow-on proposal to develop tooling for Resin Infusion (RI) and Resin Transfer Moulding (RTM) processes to demonstrate industrial scalability of this preforming technology.
Machining Optimisation and non-parallel tubes
The main objectives of this work package were: to optimise the cutting inserts and conditions used to machine the end profile of the parallel pipes and investigate the potential performance knockdown of the material due to exposure to cutting fluid during the manufacturing process. The current process performance was baselined and several alternative strategies were developed. The AMRC worked in collaboration with the tooling suppliers to develop appropriate cutting strategies for turning parallel pipes with a focus on reducing TAKT time whilst retaining part quality.
Table 3: Summary of the technology achievements
HVCMS has secured 30 highly skilled engineering roles within the Banbury Composite Centre of Excellence. David Chard, Collins Aerospace Business Development Director, noted, “The development of these technologies has not only enabled Collins Aerospace Banbury to demonstrate that it is able to support high rate composite manufacturing requirements to our customer base, but also open up opportunities that Collins Aerospace is now investigating.”
HVCMS has developed a key composite manufacturing automation capability that has demonstrated Collins Aerospace’s ability to not only deliver at significant programme rates, meeting key customer OTD metrics, but also achieve enhanced First Pass Yield rates through enhanced process monitoring and control, enabling the ACE Gold criteria to be achieved, providing further confidence of Collins Aerospace’ ability to deliver to its customer base.
The initial investigations by the AMRC into the feasibility of cost-effective complex geometry pipes have shown promise. “Collins Aerospace will be looking to increase the technology and manufacturing readiness levels of Complex Geometry Fuel Pipes in future projects, with an aim to mature the technology in readiness for Next Generation Aircraft,” highlights Andy Wragg, Collins Aerospace Engineering Director – Banbury.
Table 4: Summary of the economic impact
A number of opportunities for future exploitation of composite fuel pipe technologies have been identified by Business Development. Other opportunities for high volume filament wound composites have been identified and are being investigated in other current and proposed Aerospace Technology Institute projects. Complex geometry pipes will be further developed under the Airbus-led Wing Structures and System Integration (WISSI) Aerospace Technology Institure project.
Article sourced from: Aerospace Technology Institute