Scientific and Technical Objectives
The overall goal of Stellar is to develop the tape-laying process to cost-effectively place different reinforcements locally within a single component, minimising component weight and maximising performance.
Ensuring the industrial applicability of the selective tape-laying process
The partners will identify and specify two case study applications, one in each of 2 application areas, with a target decrease in materials usage of at least 20%. The project will consider different production rate scenarios to each of the target application areas, which may be to make a carbon intensive cost-optimized load-optimized, tailored blank for a high-performance application in 10-30 minutes, or to stamp-form a tailored blank in under 3 minutes for mass production.
Objective: ensure that the project outputs will be industrially relevant and exploitable.
Novel precursor materials for the selective tape-laying process
Some of the material combinations proposed in Stellar do not yet exist commercially, so we will develop novel thermoplastic tapes reinforced with polymer, glass and carbon fibres, using a meltimpregnation process, at speeds greater than 60m/min to ensure cost-effectiveness. The project will also produce intermediate organic sheets from at least 2 materials combinations using a film stacking process, for subsequent tape-laying and compression moulding processes, as well as at least 2 flowing compounds for compression moulding.
Objective: provide new high quality fibre reinforced thermoplastic tapes, compounds and intermediate sheets for subsequent tape-laying and compression moulding processes.
Maximising the speed of the tape-laying process for combinations of different reinforcements
The Stellar project will develop the laser assisted tape-laying process so that it has the temperature control needed to directly manufacture entire components in a single-step tape-laying process. Secondly, we will use the tape-laying process to manufacture complex preforms for subsequent stamp forming and compression moulding, with production speeds >600 mm/s. Finally, we will lay reinforcement tapes directly onto moulded or formed parts, either to produce the final component directly, or for subsequent stamp forming, with a >30% reduction in process material wastage.
Objective: generate the technical ability to selectively place different tapes in different areas of a component, for example in locating the tapes accurately, in achieving full consolidation over the full tape length and in differentially heating the various materials.
Downstream post-forming processes to increase component complexity and production rate
For production scenarios where direct manufacturing from the tape-laying process cannot achieve the production rate or complexity demanded by an end-use application, the project will develop post-forming techniques. We will develop the moulding parameters for tailored blanks and sheets for use in stamp forming and compression over-moulding, using components representative of key structural features, with a target cycle time of < 3 minutes.
The partnership will also enhance the ability to model these complex moulding processes beyond the capability of current simulation, so that we understand the moulding limitations prior to the later manufacture of demonstrator components.
Objective: significantly enhance existing stampforming and compression moulding processes by, for the first time, enabling the selective reinforcement of the parts that each process can produce.
Synchronous robotic placement of material in complex multi-material structures
We will develop a machine cell that has multiple placement heads to allow the synchronous placement of material in complex multi-material composite structures, enabling a step change in deposition rates, efficiencies and costs. We will work on the optimum control system methodology to allow active cooperation of between 2 and 4 robots on the same component, and we will implement the machine control systems and hardware needed to achieve this. We will also use machine simulation to model the improvements obtained by using synchronous robots, and to avoid crashes, and to verify the predicted process speed benefits (1.3-1.7 times faster than a single robot) that can be achieved.
Objective: enable an increase in the speed of the tape-laying process using by using multiple robots working in harmony (for example, incorporating control strategies to determine which robot has to pause and which robot may continue).
Demonstration and validation of the selective tape-laying process
The partners will assess the robustness of the developed processes through pilot processing, to determine outline process parameters. We will redesign 2 existing components for selective tapelaying, and then demonstrating the use of the process to manufacture those components. We will compare the performance of the existing parts to the parts produced from the processes developed during the project, particularly to assess the target benefits of reduced material usage and optimised part performance for weight, and we will also assess the robustness of the process.
Objective: demonstrate and validate the developed process by defining, fabricating and testing two demonstrator components.