Anstey, United Kingdom
Anstey, United Kingdom

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Antar M.,Manufacturing Technology Center Ltd | Antar M.,University of Birmingham | Chantzis D.,Manufacturing Technology Center Ltd | Marimuthu S.,Manufacturing Technology Center Ltd | And 2 more authors.
Procedia CIRP | Year: 2016

EDM and laser processing are extensively used for drilling cooling holes in various aero and land based turbine components, including combustion casing, vanes and blades. However, as it is envisaged that future generation of aero engines will typically have in excess of 150,000 cooling holes, which will result in enormous pressure on technology providers to meet some very challenging targets in relations to productivity and hole quality. This represents a significant R&D opportunity to improve the performance of current hole drilling process to keep up with the ever increasing customer demands. This paper investigates high speed hole drilling (0.8 mm diameter) of nickel based aerospace alloy (5-10 mm thick) with the state-of-the-art EDM and laser drilling machines. EDM trials were performed using GF Agie Charmilles, 7-axis Drill 300 unit and laser trials were performed using a DMG LT50 PowerDrill unit equipped with an IPG 20 kW QCW fibre laser sources. A 2-level 3-factor full factorial design was used to identify the preferred operating parameters for each process. The main investigation concentrates on identifying suitable hole drilling regimes for EDM and laser drilling process on basis of drilling speed, recast layer thickness and hole taper. Results showed a step change in drilling speed (4-5 folds) compared to previous generations of EDM and laser machines (ND:YAG laser and standard EDM drill), with significant enhancement in hole quality and integrity. EDM showed significantly better results with regards to recast layer (10-15 μm compared to -80 μm for laser) and geometric accuracy / taper particularly for thicker samples. Laser drilling, however, was far superior in terms of speed with <3s drilling time for 10 mm thick samples compared to 48s best recorded EDM drilling time.

Annicchiarico D.,Saint - Gobain | Attia U.M.,Manufacturing Technology Center Ltd. | Alcock J.R.,Cranfield University
Industrial and Engineering Chemistry Research | Year: 2014

The purpose of this paper was to evaluate the shrinkage behavior of a 316L molding feedstock. The methodology adopted a statistical approach (design of experiment) and a standard microshrinkage measurement approach. The statistical approach identified the mold temperature-parallel to the flow direction-and the combined effect of the holding and injection pressure-normal to the flow direction-as critical factors. In comparison with the polymer on which the feedstock was based, lower shrinkage values and fewer critical factors were observed. In conclusion, the lower shrinkage values were a consequence of the powder loading. The critical factors identified in the present work have found confirmation in the literature, except the absence of melt temperature between feedstock critical factors. © 2014 American Chemical Society.

Sun W.,University of Nottingham | Mohammed M.B.,Dunlop Oil and Marine Ltd | Xu L.,Manufacturing Technology Center Ltd | Hyde T.H.,University of Nottingham | And 2 more authors.
Journal of Strain Analysis for Engineering Design | Year: 2014

This article presents a comprehensive piece of research work focused on the development, validation and application of finite element modelling capability for the prediction and optimization of robotic keyhole plasma arc welding of Ti-6Al-4V thin structures. Experimental and computational investigations were carried out to characterize, develop, optimize and validate various aspects of the finite element modelling. The experimental investigations cover the determination of welding parameter envelopes using a robotic welding cell and the measurements of thermal history, distortion, residual stress and weld pool profile. The computational investigations include the development and validation of finite element models as well as the development and validation of a fully automated welding sequence optimization tool using a genetic algorithm approach. The work provides useful guidance and generic methodologies for optimum design of thin and complex lightweight structures and has formed a basis for the development of a framework on structural integrity assessment and component lifing of thin structures fabricated by welding. The optimization tool has significant potential to be conveniently modified to suit other optimization objectives and/or welding processes. © IMechE 2014.

Annicchiarico D.,Cranfield University | Attia U.M.,Manufacturing Technology Center Ltd. | Alcock J.R.,Cranfield University
Polymer Testing | Year: 2013

Purpose The aim of this paper is to optimise process conditions in micro injection moulding (μ-IM) to minimise shrinkage whilst maximising part mass. Method A Design of Experiment (DoE) approach was implemented for studying the effect of five processing parameters on shrinkage and part mass. A multiple quality criteria based analysis was used to optimise the process. Results Significant factors were found for shrinkage and part mass. Conclusions The multiple quality criteria could be optimized, and this optimization validated experimentally. © 2013 Elsevier Ltd. All rights reserved.

Scrimieri D.,University of Nottingham | Afazov S.M.,Manufacturing Technology Center Ltd | Ratchev S.M.,University of Nottingham
Advances in Engineering Software | Year: 2015

The simulation of a manufacturing process chain with the finite element method requires the selection of an appropriate finite element solver, element type and mesh density for each process of the chain. When the simulation results of one step are needed in a subsequent one, they have to be interpolated and transferred to another model. This paper presents an in-core grid index that can be created on a mesh represented by a list of nodes/elements. Finite element data can thus be transferred across different models in a process chain by mapping nodes or elements in indexed meshes. For each nodal or integration point of the target mesh, the index on the source mesh is searched for a specific node or element satisfying certain conditions, based on the mapping method. The underlying space of an indexed mesh is decomposed into a grid of variable-sized cells. The index allows local searches to be performed in a small subset of the cells, instead of linear searches in the entire mesh which are computationally expensive. This work focuses on the implementation and computational efficiency of indexing, searching and mapping. An experimental evaluation on medium-sized meshes suggests that the combination of index creation and mapping using the index is much faster than mapping through sequential searches. © 2015 Elsevier Ltd. All rights reserved.

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