Industrial Attachment ReportSubmitted by: Tham Jia Yin, Sarah Supervised by: Mr. Eric Tan (SAESL) Professor Zhou Wei (NTU) 2010 Industrial Attachment Report Abstract: As part of her Aerospace Engineering undergraduate studies, the author served as an intern at Singapore Aero Engines Services Limited (SAESL) from the 11th of January to the 11th of June 2010. The author was attached to the department of repair development. Being a Rolls-Royce jet engine Maintenance, Repair and Overhaul (MRO) workshop, the role of the aforementioned department was to increase and improve the repair capabilities of the company through the introducing and assimilating of new technologies into the company’s daily functions. This report documents the author’s 22 weeks spent as a trainee engineer under the guidance of her supervisor and mentors. The report first presents the corporate profile of SAESL as Rolls Royce’s Centre of Excellence, before introducing the working principles and different sections of a commercial jet engine. Following that, the report chronicles the major projects undertaken by the author during her period of employment, the most significant being the assisting in the setting up of a new repair cell, the Front Combustion Liner cell. Through the various tasks, the author was exposed to the many levels of work that take place in such an engineering company, from the menial, to the mundane, to the formal. After her 5-month stint in SAESL, the author has had her technical knowledge solidly reinforced, and has drastically widened her perspective on the industry. Now equipped with a wealth of new hands-on experience and workplace skills, the author is much better prepared for the working life that lies ahead. i Industrial Attachment Report Acknowledgements: The author would like to extend her sincerest gratitude to the following personnel for their invaluable assistance and guidance rendered throughout her attachment: • • • • • • • • Mr Chan Swee Heng, Manager, Engineering Department Mr Eric Tan, Head, Repair Development, and supervisor to the author Mr Koh Li Teck, Principal Technologist Mr Adrian Chia, Engineer, Repair Development, and mentor to the author Mr Alex Ong, Engineer, Repair Development Miss Khoo Yi Wen, Engineer, Engineering Department Mr Chua Koon Tiong, Inspector, Machining Cell All technicians in the various repair cells at SAESL The author would also like to thank all her colleagues, of whom there are too many to name, for their tolerance shown toward her inexperience, and their guidance in her everyday tasks. Special thanks also go out to SAESL for the wonderful opportunity presented to the author to pursue her Industrial Attachment at such an established company placed at the forefront of the MRO industry. Last but not least, the author would like to thank her tutor, Dr. Zhou Wei, and the NTU Career and Attachment Office, for making such a life changing experience available for her. ii ....................................3...........................................................3............................ Introduction to Industrial attachment.1............2........................................ 29 Planning the repair matrix ........................ 3............ Repair scheme reviews ................................. 5 The Jet Engine ............................................. 5... 21 Consumable Materials ............... 17 4................... 3 Repair Development Department ................................................................................................................... 22 Equipment capabilities ..... 22 5............. 5..... 8 Turbine.... 5.................................................................................... 3..............................................3............................................................................................................................................................. 20 4........1.......................................................................... 13 Shot peening cell .............. 9 3............. 4..........................................................................Industrial Attachment Report Table of Contents 1.............4............. 15 Machining .......................................................................... 1... 1............................. 6 Compressor........................................... 2................................................................ 1 1. 27 DMG – Automated Machining ......................................3..................................................... 11 3.......................... 2..................................................... 1 Scope: ................... 7 Combustor ......................... 6 2.............................. Orientation – Induction to the shop floor ........................ 2................................................................................................................................................................ 25 GOM machine – Optical measuring technique ................3..... The Front Combustion Liner cell.........................................................2.2.................. Standard Equipment ..............1........2..2...................................................................................................................... 1....... 25 5.......................................................................... Fan blade cell .......................................................... The Front Combustion Liner ...........4...................................................1.................................................................... 2....................................................................................................... 3......................... 4.................................................................. Fan .... Objective:.. 31 iii .................4...............................................4........................... 2 Company Profile .......................1..................................... 11 Fitting cell ............................... .................................................................... Personal Reflections and Conclusion...........................Industrial Attachment Report 6.................................................... 6.... 36 References Appendix A – Organizational Chart of SAESL Appendix B – Full Repair Scheme K004 Appendix C – Repair Capability Form Appendix D – SolidWorks Model of the Trent 500 Front Combustion Liner Appendix E – Scheme Matrix for the Front Combustion Liner Cell iv ..................... Personal Reflections ...... 33 6...........................2................................1............................................................... 33 Conclusion .... ............... 14 Figure 10 – fundamentals of shot-peening .................................... 21 Figure 15 – Flowchart of the scheme review process ........................................... b) Milling........... 30 Figure 23 – A sample repair matrix .................................................................................................................................................................. 29 Figure 22 – Probing an uneven surface before machining ...............................Clocking the reference datum before drilling ................................... 18 Figure 12 .............................................................. 26 Figure 18 – The GOM scanning unit and the triangulation principle ....................................................... 12 Figure 8 – Different surfaces of the fan blade after various processes................................................................................................................................................................ 13 Figure 9 – the workflow for the repair of a composite fairing ............ 28 Figure 20 – Inspection data of the FCL ................................................................................................................Industrial Attachment Report Table of Figures Figure 1 – Birds-eye view of the SAESL facility ..................................... 25 Figure 17 – Close-up of the FCL: a) Cooling holes b) Liner tiles..................... 8 Figure 6 ................................ 28 Figure 21 – The probe of the adaptive machine ................................. d) Grinding ......................... 15 Figure 11– Types of machining: a) Turning............................................................. 7 Figure 5 – A jet engine combustion chamber................................ 19 Figure 13 – Flowchart for the scheme review database .................................. 6 Figure 4 – Cutaway of a jet engine compressor ........................ 20 Figure 14 – The combustion rear inner case ....... 3 Figure 2 – SAESL’s in-line engine gantry (left) and cleaning line (right) ................................................................................................................................. 4 Figure 3 – Cutaway of a classic jet engine ........................................................................................ 27 Figure 19 – The Front Combustion Liner in scan (left) and in 3-D model (right) ........................................pictorial of airflow in a jet engine turbine .................................................... c) Drilling............ 9 Figure 7 – Workflow of a typical fan blade repair ... 23 Figure 16 – Cross section of a combustion chamber......................................................................... 31 v ......................... such as manpower management. attention to detail. The attachment program should enable the students to: • • • Apply their technical knowledge Gain hands-on experience Acquire the necessary skills all good engineers should be equipped with. preparing them for their professional future as engineers. The objective of this attachment is to reinforce the university’s technical and theoretical teachings by providing an opportunity for the students to apply it on valuable hands-on opportunities. Industrial Attachment is a compulsory 22-week programme conducted for students in a relevant engineering company. • Strengthen their work integrity and values through their time spent in a professional capacity at the company and • Pick up vital inter-personal skills that will help to the student build a cohesive working environment for him/her with his/her colleagues. 1 .Chapter One – Introduction to Industrial Attachment 1. Introduction to Industrial attachment 1. creativity and flexibility in application of technical know-how. Objective: As part of the curriculum for students pursuing a degree in Aerospace Engineering at Nanyang Technological University.1. etc. 2. A Development Engineer oversees the repair capabilities of SAESL. machines had to be imported. she was then put in charge of SAESL’s scheme review process. The bulk of the author’s time at SAESL was dedicated to her largest project. its software had to be set up. Knowledge of the shop floor was essential for this task. and then deciding and declaring if it was within SAESL’s capacity to carry out the respective repairs. and which types could not and hence needed to be outsourced.Chapter One – Introduction to Industrial Attachment 1. Having done so. This report will document these tasks undertaken by the author during her employment in SAESL. Incorporating cutting edge technologies like optical measuring scans and adaptive machining. and is in charge of introducing and setting up new technologies that will expand and improve the company’s present capabilities. 2 . the author was required to familiarize herself with the various repair operations being carried out in SAESL. and all the necessary paperwork from Rolls-Royce had to be processed. this cell will serve a niche market around the world for FCLs. During her attachment. This process entailed reviewing the various repair schemes provided by Rolls-Royce. The cell was developed from scratch. as the author needed to know exactly which types of repairs could be carried out. the setting up of the new Front Combustion Liner (FCL) cell. Scope: The scope of this Industrial Attachment was for the author to fully assume the role of a Development Engineer. Repair and Overhaul (MRO) repair facilities around the world. Company Profile Singapore Aero Engine Services Private Limited (SAESL) was established in 1999 as a S$185 million tripartite joint venture between SIA Engineering Company (50%).3. Figure 1 – Birds-eye view of the SAESL facility [1] SAESL is a Rolls-Royce authorized MRO shop.Chapter One – Introduction to Industrial Attachment 1. and is the only shop in the world capable of servicing the complete line of Trent Family engines as listed below: • • • • Trent 500 Series Engines Trent 700 Series Engines Trent 800 Series Engines Trent 900 Series Engines SAESL is also the first MRO facility in the world to service the new Trent 900 engine that powers the famous Airbus A380. Australasia and the Pacific Rim. It is part of Rolls-Royce’s Aero Repair and Overhaul Committee (AROC) network of Rolls Royce engine Maintenance. the Middle East. 3 . SAESL operates as the MRO centre of Rolls-Royce Trent engines within the Far East. RollsRoyce (30%) and Hong Kong Aero Engine Services Limited HAESL (20%). As part of AROC’s network. SAESL’s Compressor Blade Cell was awarded the coveted Rolls-Royce Centre of Excellence – Gold award.Chapter One – Introduction to Industrial Attachment Covering an expanse of 30. The building houses state-of-the-art aero engine MRO systems. and many more. SAESL's facility is designed to repair up to 250 Trent engines a year. Thai Airways. including the in-line gantry system for engine strip and assembly. 4 . and hasten the cycle time for each repair. Figure 2 – SAESL’s in-line engine gantry (left) and cleaning line (right) [1] In 2007. SAESL’s clientele includes Singapore Airlines. as well as the world’s first fully automated chemical cleaning line. lower repair costs. Virgin Atlantic Airlines. and the employment of such a technology helped to reduce required man-hours. This $13 million repair facility was the first in the world to employ robots as part of their processes. With such a sound customer base and a growing list of impressive accolades bearing testament to the first-class repair services offered by SAESL. Air New Zealand. Emirates. Presently. it comes as no surprise that SAESL is known around the world as a Trent Centre of Excellence.000 square metres. Qatar Airways. The development engineers constantly study emerging technologies and identify relevant ones. Repair Development Department The repair development department in SAESL is a branch of the Engineering department.4. They then undertake the project of importing the technologies into SAESL. and skilled manpower. and is responsible for introducing new technologies into SAESL’s production line.Chapter One – Introduction to Industrial Attachment 1. and provided an excellent learning ground for the author. and ensuring its full functionality in terms of hardware. This department is vital in ensuring that SAESL remains at the forefront of the MRO industry with the employment of cutting edge technology. 5 . software. 1. Approximately 10 to 20% of the compressed air then enters the engine core. in 6 . and it is this accelerated air that. The Jet Engine Figure 3 – Cutaway of a classic jet engine [2] The figure above shows a cutaway of a classic jet engine. Comprising a fan. the mechanics of a jet engine will be detailed according to its individual modules. In the subsequent paragraphs. a compressor. Fan The fan is the primary producer of thrust in a jet engine. a combustor. Functioning as a low pressure compressor.Chapter Two – The Jet Engine 2. The remaining 80% of the air is immediately expanded through the constricted exhaust of the fan case. the air that passes through the fan is compressed to almost twice its original pressure. The expanded air accelerates. 2. a turbine and an exhaust nozzle. it relies mainly on Newton’s Third Law of motion to deliver the thrust required to power a plane. then removes the swirl in the air caused by the rotating motion of the rotor. The fan. The figure above shows labels such as IP1 and IP8. and hence rotate at the same speed. some kinetic energy from the rotor is transferred to the air. The stator located downstream (seen as Variable Stator Vanes (VSVs) above).Chapter Two – The Jet Engine accordance with Newton’s Third Law of reactive forces. 7 . provides the engine with approximately 75% of its overall thrust delivered [2]. Compressor Figure 4 – Cutaway of a jet engine compressor [2] A single stage compressor is made up of an adjacent row of rotor and stator blades. functions as a low pressure compressor (LPC). The rotor blades are mounted onto a bearing drum connected via a shaft to the turbine at the rear of the engine which rotates the rotor at a high speed. 2.2. Several stages are required in a compressor. which is followed by the Intermediate Pressure Compressor (IPC). IP1 stands for Intermediate Pressure Compressor Stage 1 and IP8 for stage 8. preparing it for the next stage of the compressor. When the air passes through the rotor. However. causing a pressure rise. as a single stage is not able to accomplish the necessary pressure rise. it is important to note that the rotors are connected to a single bearing. as mentioned. the Front Combustion Liner (FCL). Combustor Figure 5 – A jet engine combustion chamber [2] The combustor handles the task of burning the large volumes of compressed air exiting the compressor. By separating the HPC from the IPC. This split compressor technology is a Rolls-Royce trademark. The air exiting the compressor is drastically decelerated.3. A spark plug then ignites the mixture that will burn in a self-subsisting flame for the entire flight cycle. The HPC operates at a higher rotational speed than the IPC due to the decreased compressibility of the pressurized air. The combustion process dramatically raises the temperature of the 8 . the two modules are connected to different sections of the turbine that will allow the two compressors to rotate at different speeds. and enters the main component of the combustion chamber. creating a highly combustible air/fuel mix. 2. and is one of the major contributing factors for the superior efficiency of Rolls-Royce’s Trent engines. hence the need for higher energy transfers. A fuel injector sprays fuel into the incoming air.Chapter Two – The Jet Engine The final module of the compressor is known as the High Pressure Compressor (HPC). acts as a reactive force on the rear of the engine. Following the combustion process. the stator is placed before the rotor. However.4. just like that of the fan. in the turbine. being a high velocity and high pressure gas stream. the air is exhausted to the atmosphere in a constricted exhaust.Chapter Two – The Jet Engine incoming air. the turbine is made up of rows of stators and rotors. The exhaust.pictorial of airflow in a jet engine turbine [2] Like the compressor. Turbine Turbine Nozzle Guide Vanes (stator) Figure 6 . 2. The excess pressure then becomes available as engine thrust when it is exhausted from the nozzle. the pressure drop in the hot air as it expands through and turns the turbine is less than its initial pressure rise caused by the compressor. Energy is then extracted from the tailored flow that creates a torque on the turbine. the high temperature-and-pressure gas is forced into the High Pressure Turbine (HPT). 9 . The nozzle guide vanes swirl the air in the direction of the turbine blades’ rotation. causing the turbine disc to rotate. and in turn drive the compressor at the front of the engine. After passing through the entire core of the engine. According to the laws of thermodynamics. this chapter concludes the introduction to the working principles of the jet engine. 10 . With that.Chapter Two – The Jet Engine contributing to the other 25% of the jet engine’s overall thrust. the FBC was different in that it was a component cell. she assisted the technicians in the cell in carrying out the above two repairs on a set of Trent 800 engine fan blades. as individual modules (for example: a high pressure compressor). Orientation – Induction to the shop floor Repair jobs come from airlines all over to world to SAESL in three forms – as a whole engine. Parts found to be damaged but still repairable are then sent to the shop for repairs according to standard repair procedures set out by Rolls-Royce. or as a single component. and subsequently.Chapter Three – Orientation on the Shop Floor 3. and replaced with new parts. In her first month at SAESL. 11 . Unlike other cells. 3.1. Assuming no abnormal damages such nicks or dents on the blades. the author was attached to various repair cells for short periods of time. There are two standard repairs that all fan blades sent for overhaul will undergo. A component cell is a stand-alone. capable of existing on its own without support from other cells. each blade will have its leading edge profile and aerofoil surface restored during overhaul. Parts found to be damaged beyond repair are discarded. to prepare her for her subsequent tasks in the company. inspection. Throughout the author’s two-day attachment. The purpose of this was to introduce the author to the different types of repair carried out in SAESL. The FBC repairs only fan blades. and is able to independently carry out most repairs that a fan blade might require. The engines and modules are stripped to their individual parts before being sent for cleaning. Fan blade cell The first cell that the author was attached to was the fan blade cell (FBC). After being stripped from the engine and cleaned. The figure above demonstrates the procedure of a typical fan blade repair. the blades which were initially designed aerodynamically for drag reduction purposes had experienced erosion of their leading edge. None were present. 12 . After several cycles of engine run. and polished them with an abrasive stone to smoothen the edge.Chapter Three – Orientation on the Shop Floor Figure 7 – Workflow of a typical fan blade repair Each engine consists 26 fan blades. The blades then had their leading edge profile checked against a standard mould provided by Rolls-Royce. The author inspected the blades visually and with ultrasound to check for surface damage or interior cracks. The author used a hand-held grinding machine to file the leading edges of the blades back to their original profile. the set of blades were sent to the FBC. This step was particularly time-consuming as the machine was only able to process one blade at a time with a cycle time of 20 minutes per blade. grinders and even penknives. This will prevent cracks from forming.2. causing the Aluminium Oxide to rub against and polish the surface. all subsequent cells that the author was attached to were process cells that specialized in processes.Chapter Three – Orientation on the Shop Floor Surface of Engine-run blade Surface of glass-peened blade Surface of vibro-polished blade Figure 8 – Different surfaces of the fan blade after various processes Following that. Fitting cell The next cell that the author was attached to was one of the most important cells in SAESL – the fitting cell. using simple hand tools like drills. Repairs in this cell are carried out manually by technicians. not components. Unlike the fan blade cell. to ensure that they were compliant to Rolls-Royce standards. After this step. Glass peening is similar to shot peening (to be discussed later). The blades were loaded onto the polishing machine and submerged into a tank of pink aluminium oxide media. her assignment in the fan blade cell was considered complete. the author brought the blades to the final station – the vibropolish station. for the surface of the blade to be blasted with glass beads. Once all 26 blades had passed the checks. the author’s last task was to measure the surface roughness of the blades. The machine vibrated the blade. As a result. the blades were loaded into the glass peening booth. 3. After the blades had been polished. this cell covers a very wide range of 13 . and is used to improve the surface strength of the titanium fan blades. After curing. Figure 9 – the workflow for the repair of a composite fairing The author spent a week at the fitting cell. because the repairs are not limited by the capabilities of the machines employed in other cells. with a honeycomb core in the middle.Chapter Three – Orientation on the Shop Floor repairs in SAESL. The fairing was then considered successfully repaired. the carbon fibre had become delaminated from the honeycomb. and work was required to bind it back. making it more streamlined and hence reducing drag. These holes were used for forcing adhesive into the sandwich. The author first drilled 1mm holes all over the carbon fibre in the area that had become delaminated. as an additional measure. and the sandwich was then clamped together to allow the adhesive to cure. blank metal plates were screwed together on both sides of the sandwich. repairing composite fairings. 14 . In the component sent for repair. making it extremely lightweight. It is made of a carbon fibre sandwich. A fairing is a light-weight structure used to cover oddly-shaped protrusions on the aircraft. known as shadow boxes. Countless small spherical particles (known as shots) are thrown at the metal surface at a very high speed. to making the metal blanks and mixing the necessary products to make the adhesive. and will prevent crack propagation. as well as other aerospace standard practices like tool box organization – tools are placed in toolboxes in customized grooves. from wielding the tools. which make accounting for the tools easy after each repair. deforming the molecules and creating residual compressive stress on the surface. Shot peening cell The shot peening cell is new in SAESL. and which helped her understand the shop floor operations much better. ensuring that no tools have been accidentally left on the component. only set up in September 2009 by the repair development department. as seen in figure 10 below.3. In her attachment to this cell. the author was able to understand and appreciate the menial jobs that the technicians were required to carry out. Through the process.Chapter Three – Orientation on the Shop Floor Although this was a complex process that took almost a day for each single fairing. 3. This internal stress will act against external tensile forces to increase the strength of the metal. the author also learned about safety standards in the work place. Shot peening is a process used on metals that will increase surface hardness. Deformed molecules Crack being pushed together Figure 10 – fundamentals of shot-peening 15 . the author was able learn a lot. 16 . the doors are closed. it is a very carefully controlled process by Rolls-Royce. the author learnt about the properties of the different metals in a jet engine and the fundamental theory of shot peening. and the rotation of the turntable. through the attachment.e. robot arm). Then. who have demonstrated their shot-peening capability to Rolls-Royce. The speed and volume of the shots being fired per second is controlled by the shot peening machine. For each type of repair of each part. and after being fired. through maintaining the shot peening machine. A nozzle is affixed to the head of a 6-axis robot. Once the part is loaded into the machine. and the shots are fired from the nozzle.Chapter Three – Orientation on the Shop Floor Rolls-Royce has stipulated the use of the shot peening treatment on many metal parts deemed to undergo a lot of stress during engine run. both before. a computer program has been written for it. as the process was completely automated. However. the part is mounted on to a rotating turntable in the booth. and the machine is set to run automatically. including SAESL. and how the shots are processed. the author learnt about the mechanics of the machine. The approval to carry out this process is granted only to a select few companies worldwide. The attachment to the cell for the author was relatively simple. In SAESL. Because shot peening is a very complicated technology due to the randomness in the firing of the shots. directing the movement of the nozzle (i. shot-peening is a fully automatic process. Also. The component to be peened first has to be masked – using rubber plugs to cover and protect the areas of the component not meant not be peened. the intensity and volume of the shots being fired. Like the shot peening cell. However. and the work piece rotates.Chapter Three – Orientation on the Shop Floor 3. • Drilling: the creation of cylindrical holes using twist drill on a stationary work piece.4. • Milling: is where the work piece remains stationary and the cutter is a rotating. 17 . multi-tooth cutter. It is one of the most important processes in any production or repair factory. and involves using a cutter to remove material from a component to achieve a desired geometry. right. left. and likewise in SAESL. down. Machining Machining is an age-old process used since the 18th century. the cutting tool on the machine is also attached to a robot. the machining robots only move in 3-axes (up. The axis of rotation of the cutter is often perpendicular to the work piece. and are manually operated. front and back). Machining can be broadly divided into 4 categories: • Turning: is where the cutting tool is stationary. removing very small amounts of material. • Grinding: a process used mainly for finishing touches on surfaces. b) Milling. When clocking the reference datum. c) Drilling. the machine will wind up cutting too deep into one side of surfaces. Likewise. and not cutting the opposite side at all. it is important that the surface to be drilled is set perpendicular to the cutting tool. in turning. the component to be machined must be placed directly at its centre of rotation. The clocking process is carried out using a pressure dial attached to the robot in place of the cutting tool.Chapter Three – Orientation on the Shop Floor a) b) c) d) Figure 11– Types of machining: a) Turning. Because the cutter only has 4 axes of motion. If there are abnormalities in the 18 . the position of the repair component is very important. If it is slightly off-centre. the dial should read a constant pressure from the spindle for the entire surface. In drilling. d) Grinding One of the most important steps in machining is the clocking of the reference datum. The author now understands the machining process much better. Figure 12 . The author was able to identify the various cutting tools. which is knowledge that will come in useful both in the production and the overhaul industry. After the part has been positioned. After machining.Clocking the reference datum before drilling This attachment was particularly interesting for the author. 19 . the repair part will then have to be re-positioned. and the operator will begin machining it. The parameters to be controlled are the speed of rotation of the component (for turning). as machining is a fundamental industrial process.Chapter Three – Orientation on the Shop Floor readings. as well as recognize the purposes and surface finish created by each tool. and the position and movement of the cutting tool. the speed of rotation of the cutting tool (for drilling and milling). the cutting tool is attached to the robot. using sandpaper to even out the texture of the metal. the operator has to finish off the machined surface by hand. The author was also able to learn from the experienced technicians and operators the speed at which the tool/work piece should be rotated to achieve a clean surface finish. and are meant to cover any form of defect or damage that may occur to any component of the engine when in use. or if it is necessary to send the part to a sub-contractor who is able to carry out the repair. The technicians at the Inspection Cell will then refer to the database to determine if a certain repair can be carried out within the SAESL facility. FRSs are designed by Rolls-Royce engineers to dictate all repair procedures. and the author was required to ensure that SAESL’s own database accurately reflected the company’s ability to carry out each repair. SAESL is a Rolls-Royce MRO shop. As such. the author’s responsibility was to constantly update SAESL’s own repair capability database according to each FRS in the Rolls-Royce database. and the part will be scrapped. To document the process. the author will use a case study of FRS K004 as attached in Appendix B. Rolls-Royce constantly updates and creates new FRSs.Chapter Four – Repair Scheme Reviews 4. Being in charge of reviewing the FRSs. known as Full Repair Schemes (FRSs). Any damages not identified by the FRSs will be considered irreparable. all repairs carried out by SAESL are governed by repair schemes planned by Rolls-Royce. servicing only Rolls-Royce engines and parts. which is a repair scheme for repairing cracks at the front flange bolt holes of the Combustion Rear Inner Case (CRIC). Repair scheme reviews The author’s orientation to the shop floor was aimed to prepare her for her next task – taking charge of SAESL’s scheme review system. the author will explain the procedure of reviewing an FRS. Rolls Royce Provides: SAESL database Accessed by: • • Input to: Full Repair Scheme Reviewed by: Author Technicians in the inspection cell SAESL engineers Figure 13 – Flowchart for the scheme review database 20 . In the subsequent paragraphs. If there were to be certain 21 . penetrant crack test equipment. After dressing.1. there are several areas that require attention. i. before being machined to the final required dimension. Standard Equipment As found in section 2 of FRSK004. It was the author’s responsibility to ensure that all equipments were available and functional in SAESL. heat treatment equipment. and finally vibration peen equipment. there exists a list of standard equipment required to conduct the repair. Following the welding. whose bolt holes have cracked during engine run. the crack is then filled with filler from argon arc welding. inspection equipment.Chapter Four – Repair Scheme Reviews Figure 14 – The combustion rear inner case FRSK004 dictates the repair of a CRIC. drill bits. degreasing equipment. hand tools. as shown in the figure above. To conduct a proper scheme review. This repair calls for argon arc welding equipment. First.e. the cracks are dressed. 4. before carrying on with the repair. machining equipment. to create a suitable profile for subsequent welding. enlarged. and in all FRSs. the CRIC is sent for heat treatment to relieve it of the thermal stresses occurred during welding. copper chills. swab etch equipment. This is to ensure that the weld filler is able to enter the space of the small crack. vapour blasting equipment. In heat treatment. 4. In order to carry out this step.Chapter Four – Repair Scheme Reviews equipment that were not available in-house. The author was required to ensure that SAESL constantly maintained a stock of all OMats required for each repair. because most machines only move along 4-axes. as important as the repair equipment. to acquire. which took a few weeks. and usually face no capability problems. This is the most complex step of the review. In the FRSK004 example.3. Consumable Materials Consumable materials. the author had to ensure that there were either other equivalent OMats available. as a repair cannot be carried out without either. and the 22 . Equipment capabilities In the most important step of reviewing a repair scheme. and if it is able to reach the specified temperatures. are the substances and products used up in the process of the repair. However. otherwise known as OMat. repairs using machines and other complex equipments face more constraints. who would then stock the missing OMat. or bring the matter to the attention of the Materials Planning department. and if it were capable of carrying out the task. 4.2. it is important to note if SAESL’s furnace is large enough. the author was then required to identify the unavailable procedures. It is. In machining. dressing and welding were manual repairs carried out by technicians. and many trips to each individual cells. it is important to note if the surface areas that require machining are accessible by the cutting tools on the machines. although smaller in scale. If there were OMats which SAESL did not maintain a stock of. the author had to assess the capabilities and limitations of the equipment. and make arrangements for the procedures to be sub-contracted to a third party vendor to complete the repair. it was necessary for the author to have a firm knowledge of all equipments available in SAESL. in the future. It was through this exercise that the author was able to learn much more about the functions and mechanic principles of the various machines. Hence. After filling out the forms and updating it into the SAESL database. A summary of the scheme review process is shown in the diagram. if SAESL was able to handle this repair. the author was required to fill in necessary paperwork in the SAESL database. they would be able to see. or if it had to be sent to a sub-contractor. or seek the opinion of an operator with such knowledge. are attached in Appendix C. After confirming all above criterion. the review would be considered complete. The standard forms. if the inspection technicians were to notice a defect on the CRIC that required a FRSK004 repair.Chapter Four – Repair Scheme Reviews author had to learn the capability of each individual machine. through the database. filled out to FRSK004. Full Repair Scheme Equipment Yes Consumables Yes No Outhouse D A T A No Request to purchase B A Equipment capability Yes No Outhouse S E Develop solution to overcome equipment limits Figure 15 – Flowchart of the scheme review process 23 . 24 .Chapter Four – Repair Scheme Reviews Through her task of reviewing and updating more than two hundred FRSs. but also benefitted from the learning experience of this task. known commonly as “the hands on the ground”. as well as established a strong rapport with the technicians. It was a meaningful task for the author. as she was not only able to contribute to the company by updating its database. the author had become more familiar with the administration style of Rolls-Royce. She also gained much more knowledge about all shop floor operations in SAESL. in the process of building a new repair cell. Figure 16 – Cross section of a combustion chamber 25 . and is the component in which the combustion in a jet engine takes place.Chapter Five – The Front Combustion Liner Cell 5. The Front Combustion Liner cell No attachment to the Repair Development department would be complete without taking up a development project. while the combustor assembly is shown in figure 5 of section 2. The Front Combustion Liner An FCL is commonly known as a combustion chamber. much of the information is confidential. As the project is still under development. The FCL is a fairly complex component due to the extremely high temperatures and velocities of the airflow involved. the new cell incorporates cutting edge technologies which will be explained in subsequent sections.1.3. she joined a team of two other colleagues. the Front Combustion Liner (FCL) cell. During the author’s attachment to the department. The first in Singapore and second worldwide to service Rolls-Royce FCLs. in excess of 2100˚C and 150m/s respectively. and cannot be discussed in detail. A cross section of the FCL is shown in the figure below. 5. acts as a diffuser to slow down the airflow coming into the FCL. The remaining air either enters the airflow through several holes all around the FCL. a) b) Figure 17 – Close-up of the FCL: a) Cooling holes b) Liner tiles 26 . the tiles are always removed before any work is to be done on it. These tiles are removable for easy maintenance and replacement. before being ignited. only a small portion of the airflow enters the FCL directly. or only rejoins the air at the end of the combustion process. as seen in b). These holes allow the cool air running outside the FCL to transpire into it. is then able to sustain a steady flame. coupled with the recirculation of the air caused by the air entering the FCL through holes in the wall. The rounded section at the front of the FCL. before moving through the gap between the tile and the wall. The walls of the FCL are lined with ceramic-coated tiles. known as liner tiles. Then. as seen in Figure 17a). and its cooling technique is shown in the figure below. Fuel is sprayed through nozzles in the head to create a combustible air/fuel mix. cooling it through convection. known as a Head. These tiles are designed to contain the heat of the flame. In carrying out repairs on the FCL. the cool air impinges on the tile.Chapter Five – The Front Combustion Liner Cell As can be seen from the figure 16. The lowered-velocity airflow. Infinitely many cooling holes are drilled into the walls of the FCL. to cool the airflow before it enters the turbine. The GOM software on the computer then transforms the coordinates into an editable mesh. Cameras α Projector l β d? Figure 18 – The GOM scanning unit and the triangulation principle Through measuring the coordinates of the fringe patterns projected onto the FCL surface.Chapter Five – The Front Combustion Liner Cell 5. A semi-generated 27 . the solid surface of the FCL is then generated. SAESL imported a relatively new technology of 3D optical measuring from German company GOM – their Advanced Topometric Sensor (ATOS) system for the purpose of inspection. The central projector on the ATOS unit projects a unique fringe pattern on the FCL. After making necessary adjustments to the mesh (removing anomalous points and redefining complex edges). and the two cameras mounted on either side of the projector is able to measure the 3-D coordinates of the fringe pattern based on the triangulation principle as illustrated in the figure below. ATOS generates a cloud of 3D coordinates that map out its surface.2. GOM machine – Optical measuring technique In attempting to automate all processes in the FCL cell. Figure 19 – The Front Combustion Liner in scan (left) and in 3-D model (right) As mentioned previously.Chapter Five – The Front Combustion Liner Cell (software is not completely set up) FCL is shown in the figure below. Figure 20 – Inspection data of the FCL 28 . The GOM software is then able to calculate and display the surface deviation between both models (example shown on following page). and hence highlight the areas of deformation on the live FCL. is created from technical drawings from Rolls Royce. created by the author on the SolidWorks program. Inspection is done by comparing the solid surface of the live FCL to pre-existing Computer-Aided Design (CAD) data. and represents the ideal shape and geometry of the FCL. shown above and in Appendix D. the GOM ATOS system is used for inspection. The Solidworks model. and in Appendix D. DMG – Automated Machining The other new technology employed in the FCL cell is the DMG (Deckel Maho Glidemeister. used to carry out adaptive machining. the FCL. Figure 21 – The probe of the adaptive machine 29 . This saves time as there is no need to clock and adjust the position of the as opposed to conventional machining (section 3. As it is still under development. Adaptive machining is an up-and-coming technology in the aerospace industry[3].3. and hence set the reference datum of the cutting tool. a German machining company) machine. 5. information regarding its purpose in the FCL cell is confidential to SAESL and will not be discussed in detail. In the subsequent paragraphs. not only does it save time. This is to determine the exact position of the FCL. and SAESL is one of the first MRO firms in Singapore to employ it in its operations.Chapter Five – The Front Combustion Liner Cell Although the setup of the GOM inspection is still a work in progress. The adaptive DMG machine begins by probing the surface of the component. the advantages are clear.4). the author will explain the principle of adaptive machining. inspection is also less subject to human error and oversight – one of the largest problems with visual inspection. in this case. By automating the process. As jet engines run at extremely high temperatures. and is able to adjust accordingly to give an even thickness on the finished product. This helps to avoid over/under-machining. many components. and is able to effectively communicate the path that the cutting tool should take when machining the weld. As welded surfaces are often uneven. and coupled with the surface probing by the adaptive machine. the cutting tool knows the exact topography of the surface. the GOM technology will be able to detect the deviation of the part’s geometry. which is a common problem for conventional machining when faced with uneven surfaces. With intelligent adaptive machining. for example. the probe traces the surface of the weld. Figure 22 – Probing an uneven surface before machining [3] Another application of the adaptive DMG machine that is particularly relevant to the aerospace industry is its ability to machine components that have been distorted out of their original shape. a customized toolpath can be generated for the machining of the distorted part that would otherwise have been a slow and manual process. a welded area that needs to have its geometry and dimensions restored. especially the FCL. In such cases.Chapter Five – The Front Combustion Liner Cell The DMG machine then uses the same probing tool to probe the surface that requires machining. 30 . that come in for repair are seldom still in their original shape due to heat distortion. such as cleaning. as certain repair processes may interfere with each other.Chapter Five – The Front Combustion Liner Cell In helping to set up the two state-of-the-art machines in the FCL cell. or any other component in question. one. the FCL must first be welded before being machines). if the repair scheme calls for welding before machining. and cannot be simply combined. while keeping an agile mind to deal with all the problems that crop up along the way.4. The repair matrix. 5. There are several repair schemes that govern the repairs of an FCL. the author has gained much knowledge. and any FCL that comes into SAESL would possibly require none. combines all the repair schemes of the FCL. recognize their potential to suit your needs and adapt it accordingly. A simple example is shown below: Component X Cleaning Inspection Water jet stripping Plasma coating Welding Machining Repair 123 x x Repair 456 x x x x x x x Figure 23 – A sample repair matrix 31 . as attached and shown in Appendix E. and groups similar processes. or all of the repairs. more. Not only did the task provide her with a glimpse into the future of the MRO industry in optical scans and adaptive machining. Planning the repair matrix The author’s other task with the FCL cell was more administrative – planning what is known as a repair matrix. it also taught her the fundamentals of what it meant to be an engineer – to identify new technologies.e. or machining together. Care must also be taken when fitting the repairs together. The order of the individual repair schemes cannot be jumbled (i. Chapter Five – The Front Combustion Liner Cell By planning such a matrix. and market competitiveness. Such efficient systems allow SAESL’s manufacturing processes to be leaner. hence contributing to SAESL’s overall productivity. as the repairs are able to run side-by-side. it ensures that all FCL components that arrive in SAESL for repair is able to have any combination of repairs carried out on it in a very efficient manner. before starting on repair 456. 32 . instead of first completing repair 123. When my mentor. his purpose was for me to not only gain hands-on experience with the engine components. In helping to carry out repairs. Personal Reflections and Conclusion 6. firstly. He believes that in order to know a process. However. to follow. I was grateful for the opportunity to see and handle the engine components that I had previously only read about and seen pictures of in textbooks. This greatly enhanced my understanding of the jet engine. Without a good understanding of the technicians’ capabilities. planning the repairs and procedures for the technicians. as they imparted their years of experience and wisdom to me. This understanding is important for an engineer. Personal Reflections The 22 weeks I spent at SAESL has been an incredible learning journey. to know their problems.Chapter Six – Personal Reflections and Conclusion 6. I was able to build up a good rapport with the technicians in the various cells. person or machine well. more importantly. arranged for me to be attached to the various repair cells. so as to enhance my own 33 . through my understanding of its individual components. Through my attachment at the repair cells. engineers will face problems in their planning processes. to respect. as engineers are the “brains” in the office. It has provided me with a wonderful introduction not only to the career and daily life of a professional aerospace engineer. but also to the fundamental operations of any engineering firm. I was also able to fulfill Adrian’s target for me – to know the capabilities and the limitations of the technicians and the tools they access. but also to have a greater understanding of the technicians and the work that they do. one has to get his hands dirty.1. eat and sweat with them. commonly known as the “hands”. Adrian. and will certainly be one that I carry with me through my working life. most interesting task – the setting up of the FCL cell. This task exposed me to many engine parts that I did not have a chance to handle while I was in the repair cells. Of course. Setting up this cell was quite a roller coaster. In my second task at SAESL. the plasma cell. although seen as a mundane task. this task became relatively simple. and hence improve my planning capabilities as an engineer. The main machines. These included the cleaning line. I felt that this task really familiarized me with the standard operations of an MRO. However. was actually very interesting for the author. This enabled me to learn more about the various cells not just in SAESL. and several other cells that I was formerly unfamiliar with. as explained in Chapter 5. Repair and Overhaul shop. Having made friends with the technicians. as I was able to seek their opinions on SAESL’s or even their own repair cell’s capability on the various repairs. as I had only worked on a few components. as most jet engine companies. In addition. adopt similar working styles. and I regret that it was not able to be completed before the end of my attachment. This task taught me several key skills of becoming an engineer. building their MROs around repair schemes dictated by the engine makers. Alex. and saw their potential to meet his needs in the FCL cell. and indeed. who noticed these up-and-coming technologies.Chapter Six – Personal Reflections and Conclusion understanding of the shop floor. but in any standard jet engine Maintenance. I was also introduced to other repair and process cells outside of the four cells I was attached to. the setting up of these machines proved to 34 . were the brainchild of my colleague. taking charge of the scheme review database. the GOM and the DMG. All in all. such as General Electric and Pratt and Whitney. the most enriching learning experience was my most important. that is not true. and be able to deal with any problems that the machines may throw at you. However. as is shown in Appendix D. As engineers. but in other industries as well. Another learning journey was the background work that went on for the setting up of the FCL cell. when CAD models were required for the GOM machine in the FCL cell. However. This task has equipped me with many critical professional skills that can be applied to my career. with safety officers to ensure that safety standards are being met. not only in engineering. but it is important to be willing to learn in order to maximize your own productivity for the company.Chapter Six – Personal Reflections and Conclusion be no simple task. A new problem arose from the machines almost every day in the starting stages. I learnt the importance of being a quick and critical thinker as an engineer. and was able to pick up the skill in time to draw the rather complicated FCL model. An engineer that handles a project will have to liaise closely with the management for their support. 35 . When I first entered SAESL. and engineers must also display communication prowess in seeing a project to its successful completion. The second thing that I learnt was the ability and willingness to pick up any new skills that may be required of you in your workplace. all good engineers must learn to work with machines. in this day and age. A project is never a one man show. However. I borrowed books from libraries. or any Computer Aided Design software for that matter. machines are extremely vital in any engineering process and hence. Machines. will never be perfect substitutes for human labour. and through learning to identify and overcome these problems on a daily basis. no matter how developed they become. I had to learn it quickly to meet this need. I learnt that we may not always have the necessary skills. it is easy to assume that our responsibilities are mainly to handle the machines. etc. sought help from online forums. I had little knowledge about Solidworks. with financial managers to ensure that the project is operating within budget. Chapter Six – Personal Reflections and Conclusion Along the way. must be willing to learn the things he/she does not know. 6. For example. of which there are too many to document in this report. and the aerospace industry. will be very useful to my academic pursuit. These programs will greatly simplify processing the database for my colleagues in the future. I have also taken up several small projects. Conclusion In conclusion. and who made my initiation to the working life very enjoyable. who went out of their way to assist me in my inexperience. Their warm-heartedness was very much appreciated to a fresh student who had not worked in the capacity of an engineer before. where I am sure my increased knowledge of the jet engine. and I sincerely hope to have the chance to be their colleague once again. and that the projects and tasks that I have undertaken will be useful to their operations.2. I would like to thank all my colleagues in the Engineering Department. I have written computer programs to automate the processing and updating of information for databases in SAESL. I have learnt that a willing attitude is very important in the workplace. I hope that I have been of good service to SAESL. and must always help your colleagues when possible. The lessons and skills that I have picked up in SAESL will accompany me no matter where I go. One must never be too calculative about his/her own workload. and I am honoured to have completed my Industrial Attachment here. Most importantly. SAESL is indeed a company at the forefront of the MRO industry. and I now await my return to school in September 2010. 36 . d. (n. [3] Peter Dickin.com. from http://www. The Adaptive Approach. United Kingdom: St Ives Westerham Ltd. The Jet Engine. November 2008.html [2] Rolls Royce.Chapter Seven .References References [1] Singapore Aero Engine Services Limited. Control Engineering Asia .saesl. (2005).sg/index.) Our Facility Retrieved 21 May 2010. Technicians & Trainees Head NDT/ Cleaning Oh Inn Chiam Inspectors. Trainers. Operators & Trainees Head Plasma Coating Ng Boon Wee Inspectors. Trainers. Trainers. Despatch Prep & mvmt Module. Technicians. Operators & Trainees Head Sentencing Ng Kwee Liang Inspectors. NDT. Head of Marketing Liason Credit Control Product Engineering Workscope Requirement SB Control / AD Technical Library Process Sheets Safety Workscope T.Appendix Appendix A – Organizational Chart of SAESL SAESL STRUCTURE . Technicians & Trainees Head B3 Yeo LP. Greg. Leonard Inspectors. Maintenance of Equipment Engine Receipt. Operators & Trainees Head Gen Repairs I Yap Joo Ann Inspectors. Prepare for Test. JAA Liason Continuous Improvement Process Compliance Material Planning Procurement Control of Vendors Shipping and receipt of Goods Warehousing Kitting 4 Layers Structure To Man an Integrated Business and Production Processes Clean. Technicians. Trainers. Trainers.Key Roles / Responsibilties CEO Gary Nutter Snr Mgt Asst . Trainers. Technicians.Elsie Chan Mgt Asst . Build. Choy WP. Strip. CAAS. Compressor Blade Sean Ho Component Exec Compressor Blade Inspectors. Trainers. Operators & Trainees Fan Blade Inspectors. Trainers. Operators & Trainees Head Gen Repairs II Randy Yap Inspectors. Chang Inspectors.Stephanie Sim Manager Finance & Admin Woo Lai Kuen Head Fin A/g Nicholas Cheong Finance Exec Finance Asst Senior Mgt Acc Audrey Pang Accountant A/C Execs A/C Assts Manager Human Resources Christina Lee Manager Engineering. Trainers.V. Evaluations HS&E Direct access for Quality related matters ISO 9000/ 14000 QA Admin & Audit Technical Records FAA. Technicians. HS&E Chan Swee Heng Head Engrg (Overhaul Support) Gan Chin Yee Snr/Tech Svc Engrs Asst Tech Svc Engrs Head Engrg (Repair & Support) Chris Chu Engineering Specialists Snr/Tech Svc Engrs Asst Tech Svc Engrs Technical Coordinator Principal Technologist Koh Li Teck Lab Technicians & Operators Head HS&E Johnny Cheng HS&E Exec Manager Quality & C I Tay Hang Chua Head Quality Ganesh Quality Engineer Training & Dev Engineer Head Quality Ku Eng Chuan Manager Production Leck Tea Kiang Head B0 Hamzah. Payroll Learning & Devmt Employee Relations Grievance Procedure Cust Biz Exec (Head) David Su Cust Biz Execs IT Executives Cust Biz Coordinators Contract Management for IT outsourcing Master Planner Production Planning Production Status Snr/Quality Engineers Asst Quality Engineer Tech Rec Officers Facilities Maint Finance & A/Cs Function Business Plan deviation monitoring Liason with auditors Prepare Company Finance Manual Provide Financial performance Company Secretary Cash Management Asset Cashier Credit Control Legals Facilities Maintenance Black Belt Catherine Adrian Trainee Black Belt Siew Tin Head of Biz Process Marketing Sales Bio Evaluation Customer Comm & Sppt Margin Protection Contract Maintenance HAESL. Technicians. Strip & Build. General Repairs Plasma Spray Fan Blade Cell Compressor Blade Cell Lab Dev Process Improvements Updated as at 19 May 2009 . Technicians & Trainees Head BET1 (Test Cell & E&I) Sean Boo Inspectors. Technicians. Operators & Trainees Head Gen Repairs III Lewis Foo Inspectors. Operators & Trainees Head Procurement Andy Goh Procurement Execs Head Log & Warehousing Jeffrey Ng Logistics Log Execs & Log Assts Warehousing Store Inspectors Warehouse Assts Head Material Planning Ravind Material Planners Kitting Assts Head Material Planning II Gary Goh Material Planners Kitting Assts Manager Cust Business Lawton Green Manager Planning & IT Khoo Kee Swee Head Planning & IT Iris Tan Prod Planners Head HRM Lynn Lim HR Execs Head HRD Ferry Falco HR Exec Staff Recruitment Compensation & Benefits Mgt. Trainers. Trainers. Technicians & Trainees Head Tham JL Equip Maint Tech Head NDT (Standards) Hendrich Lim Manager Component Repair & Material Tan Wai Meng Head. Technicians. Appendix Appendix B – Full Repair Scheme K004 . Appendix Appendix B – Full Repair Scheme K004 . Appendix Appendix B – Full Repair Scheme K004 . Appendix Appendix B – Full Repair Scheme K004 . Appendix Appendix B – Full Repair Scheme K004 . Appendix Appendix B – Full Repair Scheme K004 . Appendix Appendix B – Full Repair Scheme K004 . Appendix Appendix B – Full Repair Scheme K004 . Appendix Appendix B – Full Repair Scheme K004 . Appendix Appendix B – Full Repair Scheme K004 Appendix Appendix B – Full Repair Scheme K004 Appendix Appendix C – Repair Capability Form Appendix Appendix C – Repair Capability Form . Appendix Appendix D – SolidWorks Model of the Trent 500 Front Combustion Liner . Appendix Appendix E – Scheme Matrix for the Front Combustion Liner Cell . Appendix Appendix E – Scheme Matrix for the Front Combustion Liner Cell . Appendix Appendix E – Scheme Matrix for the Front Combustion Liner Cell . Appendix Appendix E – Scheme Matrix for the Front Combustion Liner Cell . Appendix Appendix E – Scheme Matrix for the Front Combustion Liner Cell . Appendix Appendix E – Scheme Matrix for the Front Combustion Liner Cell . Appendix Appendix E – Scheme Matrix for the Front Combustion Liner Cell . Appendix Appendix E – Scheme Matrix for the Front Combustion Liner Cell . Appendix Appendix E – Scheme Matrix for the Front Combustion Liner Cell . Appendix Appendix E – Scheme Matrix for the Front Combustion Liner Cell .