SURFACE INTEGRITY CONSCIOUS HIGH-PERFORMANCE HYBRID MACHINING FOR SAFETY-CRITICAL SUPERALLOY AEROENGINE PARTS

Project Information

STIMULANT

Grant agreement ID: 754807

DOI

10.3030/754807

Project closed

EC signature date 3 May 2017

Start date 1 October 2017

End date 30 September 2021

Funded under

• SOCIETAL CHALLENGES - Smart, Green And Integrated Transport

Total cost

€ 858 763,75

EU contribution

€ 759 320,88

Coordinated by

THE UNIVERSITY OF NOTTINGHAM
United Kingdom

Periodic Reporting for period 3 - STIMULANT (SURFACE INTEGRITY CONSCIOUS HIGH-PERFORMANCE HYBRID MACHINING FOR SAFETY-CRITICAL SUPERALLOY AEROENGINE PARTS)

Reporting period: 2021-04-01 to 2021-09-30

Summary of the context and overall objectives of the project

STIMULANT aims to develop and demonstrate “surface integrity conscious” hybridization of machining processes for safety-critical aero-engine parts that is able to deliver a step-change in Material Removal Rates (MRR) and reduction in production costs. STIMULANT will take key knowledge at different levels of maturity that exists within Consortium, and progress it, via Standard Features (StdFs) methodology, to the demonstration on “engine-like” safety-critical parts.
STIMULANT’s Objectives are scaled on 3 Phases:
Phase 1 – Standard features (StdF) identification
- Decompose families of critical-safety aero-engine parts into classes of StdFs with technical, functional and economic characteristics to allow selection of single/multiple hybrid machining methods that minimize manufacturing costs.
Phase 2 – Validation of individual hybrid machining processes
- Develop and test a Spatially & Temporally Heat-Controlled Hybrid High Speed Machining (Hy-HSMill) for high MRR and cost efficiency and provide predictable properties of workpiece surface integrity and fatigue performance.
- Develop and test a Dynamically Erosion-Controlled Hybrid Waterjet Machining (Hy-WJM) for high productivity and geometrical accuracy of free-forms by controlled-depth, i.e. waterjet milling, and complex contours by waterjet through-cutting and demonstrate it as StdFs with high surface integrity and fatigue performance.
- Develop and test a Dynamically Material Removal Controlled Hybrid Laser Waterjet Guided (Hy-LsWG) machining for generating cost-efficient and high geometrical accuracy of complex geometry surfaces by controlled-depth milling and through-cutting and demonstrate it as StdFs with high surface integrity and fatigue performance.
Phase 3 – Demonstration of hybridization of machining processes and routes
- Demonstrate the hybrid machining methods validated on the Phase 2 on “engine-like” safety-critical parts and integrate them on hybridized processing routes for cost-effective machining of safety-critical aero-engine part.

With a focus on maximising the surface integrity after machining, the aim of STIMULANT was to develop to the industrial implementation stage (TRL6) three non-conventional machining processes presenting the potential to produce a step-change in production rates and cost reduction: Laser Assisted Machining (LAM), Abrasive Water Jet (AWJ), Laser Micro Jet (LMJ). These non-conventional machining processes have demonstrated the capabilities to accomplish double productivity rates, lower costs, and the creation of special geometries. The generated results enabled the manufacture of components on Inconel 718, which has been validated through the establishment of a hybrid fabrication routes for two aeroengine parts with different safety requirements combining the three novel techniques in a production set-up.

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

During this reporting period, the project has progressed well following the work plan. The materials for machining tests and demonstration has been procured and delivered to the workpackages leaders for the development and test of S&T heat controlled Hy-HSMill, Hy-WJM and Hy-LaWG processes. The machining setups for S&T heat controlled Hy-HSMill, dynamically erosion controlled Hy-WJM and dynamically controlled material removal Hy-LaWG have been validated. Standard features have been selected for each process. Mathematical models have been developed and validated for controlling these processes. The pilot StdFs and their quality assessment including surface integrity, geometrical accuracy, residual stress, and fatigue life have been generated as the proven working procedure. Based on these evaluations the process parameters have been optimized for all the proposed hybrid machining process.

Within STIMULANT, three novel hybrid machining processes, namely Laser-Assisted Milling (LAM), Abrasive Water Jet (AWJ) machining and Waterjet-Guided Laser (WGL) machining, have been successfully developed to reach the demonstration stage (TRL6) for feasibility of implementation in safety-critical components for the aerospace industry. These novel technologies have demonstrated the ability to produce a step-change in material removal rates and reduction of costs while maintaining a high level of quality (i.e. surface integrity) of the workpieces after machining compared to conventional machining techniques.
Moreover, the high impact of the results achieved during the project can be clearly seen in the successful publication of 6 peer-reviewed research papers in the top journals of their areas, as well as in the interest and attention raised among professionals during the exposition of results in the most renowned international conferences. In the future, it is expected the continuation of the development of the technologies of STIMULANT by the individual partners of the consortium, as well as by other institutions, for introduction into production environments. Additionally, the universities and research centres will continue to offer practical workshops and demonstrations to postgraduate students and industrial professionals to further promote the reach and scope of the achievements and results arising from the novel manufacturing technologies investigated in STIMULANT.

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)

STIMULANT aims at developing hybrid machining processes with high material removal rate while guaranteeing good surfaces integrity at the same time with the reduction of cost of the engine parts manufacturing, which will be affordable and thereby enabling a competitive European aerospace industry. This will support the continued development of rotating frames technologies, while at the same time bring benefits for conventional engine architectures like hot section components in a geared ducted fan concept.
During this reporting period, STIMULANT has well developed hybrid machining processes for the engine parts manufacturing with increased material removal rate and while improving the component performance, thus to enable cost reduction on machining difficult-to-cut materials at minimal workpiece surface integrity. This technology will be transferred to other high value-added manufacturing industries (e.g. nuclear installations, automotive, defence, moulds and dies) where the fatigue performance of the parts is a key importance. Hence, it can be expected that the results of STIMULANT will be exploited in the broad EU engineering environment aiming to stimulate the commercial applications, cost reductions, safety and technical innovation thus to enabling a competitive European aerospace industry.

The high impact of the results achieved during the project can be clearly seen in the successful publication of 6 peer-reviewed research papers in the top journals of their areas, as well as in the interest and attention raised among professionals during the exposition of results in the most renowned international conferences. In the future, it is expected the continuation of the development of the technologies of STIMULANT by the individual partners of the consortium, as well as by other institutions, for introduction into production environments. Additionally, the universities and research centres will continue to offer practical workshops and demonstrations to postgraduate students and industrial professionals to further promote the reach and scope of the achievements and results arising from the novel manufacturing technologies investigated in STIMULANT.

Fatigue testing of specimens via 3-point bending test to evaluate surface integrity after machining.