THERMOFORMING STATION PROJECT - University of …userweb.eng.gla.ac.uk/philip.harrison/Teaching/2007...

Student: Laurent Maurel From 04/08/06 to 31/09/06 Supervisor: Philip Harrison University of Glasgow

Student: Laurent Maurel Supervisor: Philip Harrison

IST Teacher: Catherine Grondin

THERMOFORMING STATION PROJECT

Department of Mechanical Engineering

Final Year Project

Student: Laurent Maurel From 04/08/06 to 31/09/06 Supervisor: Philip Harrison University of Glasgow

CONTENTS

I. INTRODUCTION ................................................................1

II. PROJECT ANALYSIS ....................................................2 II.1. Motivation ........................................................................................2 II.2. Project environment .........................................................................3 II.3. Materials...........................................................................................3 II.4. Research and understanding the process..........................................4 II.5. Expected characteristics and hypotheses .........................................6

III. DESIGN THE THERMOFORMING MACHINE .......6

III.1. Technological solution research .....................................................6 III.2. Consultation job ..............................................................................8 III.3. Equipment choice............................................................................9 III.4. Drawing and assembly....................................................................9 III.5. Economical analysis and partnership............................................12

IV. MANUFACTURE AND ANALYSIS ...........................12

IV.1. Manufacture and updating ............................................................12 IV.2. Simulations ...................................................................................13

V. DISCOVERING OF A NEW ENVIRONMENT ........16 V.1. Professional experience..................................................................16 V.2. Cultural immersion ........................................................................16

VI. CONCLUSION ...............................................................19

VI.1. Final result project ........................................................................19 VI.2. Personal contribution ....................................................................19

Student: Laurent Maurel From 04/08/06 to 31/09/06 Supervisor: Philip Harrison -1- University of Glasgow

Fig.1 : Glasgow University

I. INTRODUCTION

For the engineering training at IST Midi-Pyrenees, my final year project was based at Glasgow University in Scotland. It has taken place from the 14th of August 2006 to the 12th of January 2007 at the engineering mechanical department. First of all, this is a brief introduction about where I have worked. Glasgow University (fig.1) is one of the oldest universities of Scotland. Founded in 1451 by Pope Nicholas V, it had welcomed prestigious researchers and inventors for centuries. Names like Lord Kelvin, Adam Smith and James Watt studied and worked in this university and we can associate six researchers having obtained a Nobel Prize. Currently, this University is classed at the 81st place of the best world universities. In 2006 16,000 undergraduate students and 4,000 postgraduates have enrolled. The University of Glasgow leads studies in various fields. The mechanics department works on the development of new materials. Indeed, it search to experiment the composite which is a material created at the end of the XX century. Scotland works in the research and development of high-tech design and manufacture of aeronautics, space, motorcar and maritime process, such as B.A.E systems, Rolls-Royce, and the Navy. To stay on the top of this evolution, material department would like to seek these researches on the composite. Consequently, a research group has been constituted. They are geared towards four broad fields: constraint based fracture mechanics; micromechanical testing and characterization; adhesives and polymer composites and at least corrosion and erosion corrosion. In the context of this research, Dr. Philip Harrison, asked me to design a thermoforming station to experiment continuous fiber reinforced composites (CFRC). This is the report of my final year project. I am going to present my activity on three points: in the first instance, the project description will be expressed with the need presentation and the research method to understand the process. Secondly, we shall see how the thermoforming machine was designed. That is to say the envisaged technical solutions and conception steps. The third part will deal with the solutions making and the behavior parts analysis depending on the process. Lastly, I shall develop a chapter concerning my integration in Scotland and shall present the professional experience acquired over these five placement months.


II. PROJECT ANALYSIS

II.1. Motivation Need to satisfy The forming of composite sheets requires the design and manufacture of a thermoforming station. The University of Glasgow wants to follow the industrial progress and be at the top of the technology. For this reason, it needs to have a device to make composite parts in order to experiment. Aim The aim is to predict the composite behaviour according to the process parameters. For that, we could compare practical results to simulations. This work allows to predict provisional results from different experiments. The overriding goal is to improve the industrial manufacture of composite parts. Cause The industrial evolution is geared towards the composite part manufacture. Nowadays, much research has been aimed at improving the manufacture and the prediction of the material behaviour. The University of Glasgow has not got any apparatus to perform experiments on forming composite material. Thermoforming is a new faster manufacture method. Therefore, material department wants to perfect a suitable machine within cost and time constraints via a student project. Objective For this project, these were the tasks:

• To research and understand the process of forming composite parts. • To design a machine forming apparatus (using CAD software) • To oversee manufacture and assembly • To optimise the manufacture process of CFRC • To perform experiments to investigate the effects of various process parameters • To simulate the process linking with experiments depending on the project progress

Budget The University of Glasgow supplied a £1,000 budget. It was used to purchase the equipment, general supplies (e.g., screw, washer, nut, etc) and composite material. The manufacture and assembly was at the university workshop. Therefore, this study doesn’t deal with this cost.

Appendix 1: Project definition


II.2. Project environment After the description of the main project characteristics, it is significant to define the environment. It allows to know the role of each person. In a second time, a Gantt chart will be established to determine the succession of activities during the five month project. a) These are the people who worked on the project:

• Philip Harrison: Project supervisor, he has to help to understand the process and valid work.

• Laurent Maurel: French student leading the project. My role is to design the thermoforming station and do experiments depending on the progress.

• Workshop technicians: People in charge of making parts for University projects. They have to machine parts of the machine and give me advice on the design.

• Laboratory technician: He could give me information on the available instruments, machines and on the environment of the future thermoforming machine. Also, he could help me to execute experiments.

• Secretary: Administrative staff of the University. She is in charge of administrative documents like purchase forms, budget demand. Moreover, she advises me on the university rules.

b) Describe the schedule:

This Gantt chart (table1) describes the tasks sequence in the time that I have to do. It allows me to follow the work progress and to inform project interacters. Its role is to know the longer way which involves inevitable delay. Therefore, it will be regularly updated to be sure to archive the final objective.

Appendix2: Project description

Appendix 3: Updating the Gantt chart

Global Gantt Chart

11/08/

2006

26/08

/2006

10/09/

2006

25/09/

2006

10/10

/2006

25/10/

2006

09/11/20

06

24/11

/2006

09/12/

2006

24/12/20

06

08/01/

2007

Research and understanding

Design the machine

Manufacture

Experiments

Simulations

Write reports

Spare week

Tas

ks

Time

Appendix 4: Project progress

Table 1: Preliminary Gantt chart


Fig.2: Composite material

II.3. Materials For this study, we will employ a material called CFRC (Continuous fibre reinforced composites), which is a composite material (fig.2) which uses long continue fibres composing the reinforcement. A composite is constituted by two materials: a matrix and reinforcement.

• The matrix material surrounds, maintains and protects the reinforcement. Its main goal is to allow the cohesion of the structure and the transmission of stresses towards the reinforcement.

• The reinforcement material ensures the mechanical behaviour of the composite (e.g., resistance, stiffness). Its making influences directly the mechanical characteristics of the composite.

A composite material is heterogenic and anisotropic. That is to say, it is composed different part and these properties vary according to the studied direction.

Composition of Composite Materials

• Matrix materials: polymers (thermoplastic or thermosetting), metals, ceramics • Reinforcement: fibres and particulate: Glass, Carbon, Organic, Boron, Ceramic, Metallic

Among composite materials, three kinds of them interest us:

• Glass reinforced polypropylene composites: thermoplastic composites • Carbon fibre / epoxy matrix prepregs: thermosetting composite • Self-reinforced composite (SRC): thermoplastic composite

It can appear in two forms, experiments will help us to define their behaviour, their advantages and inconveniences. These composite can be presented in two ways: (fig.3 and 4)

The manufacturing difference between these two materials is that the fabric does not need to be preheated before it is formed. This parameter will be significant for the result of experiments.

II.4. Research and understanding the process a) Information from my supervisor and the general literature: In the beginning of the project, it is difficult to have a complete view. Therefore, the first step was to have a meeting with my supervisor to define globally features of the project. (e.g., aim, objectives, budget, machine characteristics, work environment, etc). The PDS (Project Design Project specification) was elaborated, it describes the specifications formally. This

Fig.3: Pre-consolidate sheet

Fig.4: Fabric


document is useful to be a reference for the project presenting the principle functions, constrains and products to provide to the University. My second activity was to find out composite material on internet in order to understand behaviours and characteristics for each one. This work is indispensable for the remaining of the study, especially for meetings with professionals and carry out experiments. Thus, this information research allowed me to list suitable processes to make composite parts. After studying them, a preliminary process will be worked out. b) To Read reports: Reports written by students helped me to understand the way I have to work. Important information brought me details for the design, in particular the forming machines description: vacuum bag molding, pressure bag molding, diaphragm forming, autoclave systems, matched-mold techniques (using a press) and hydroforming. After their examination, the main advantages and inconveniences of each were shown. At this point, a rough solution began to be drawn using both the pressure and heating. C) To meet a manufacturer and a research group: After this first investigation, my supervisor and I met a group of researchers at the Glasgow School of Art. It was very enriching because the process of plastic (Silicone) manufacturing was explained to us. Two experiments were carried out, instead of the plastic sheet, we put a composite sheet in a vacuum forming. The result is interesting but unsatisfactory. During the forming, the composite sheet was sealed to the frame and cannot move. The composite is an inextensible material contrary to the plastic. We noticed a tear where the composite had been sealed. Furthermore, the temperature must be precisely controlled during the process to have an optimal result. To have an industrial example, we visited a company working for the BAE systems. There were automatic vacuum forming machines (fig.5) and we could know complementary information.

Further to these examinations, our attention focused on a system combining several processes, to adapt itself to our material according to our budget. We decided to develop a press on which we could heat and cool tools.

Heating Silicon sheet

Model

Vacuum consolidation Result

1 2 3 4

Fig.5: Process of vacuum forming


II.5. Expected characteristics and hypotheses Using previous information, the solution was to create a machine with two tools (Male and female). These tools should resist to both the composite material consolidation pressure (i.e. solidification of a dissimilar) and high temperatures. a) These are chosen specifications for the future thermoforming station:

• Increase and decrease the temperature from 20°C to 200°C quickly • Adopt a spherical shape for tools respecting two bend radiuses (60mm and 20mm) to

avoid right angles • Adapt the tools dimension to the formed composite sheets • Leave a uniform gap between tools depending on the formed material thickness • Respect a £1,000 budget for the entire project • Set up a pre-heater device for Pre-Consolidated materials (i.e. composite sheet) • Control and fit the tools equipment • Maintain in position composite sheets during the forming depending on the behavior of

these. • Allow a movement of composite material during the pressing • Remove easily the formed part

b) Hypotheses: Further to this description, hypotheses were established and will be checked in simulations and experiments:

• Change the temperature quickly: in 5 minutes maximum, to have a correct consolidation • Put a gap of 2mm between tools (further to available materials at the University). This

one can be increased depending on the thickness of the future composite sheets • Control 3 temperatures at least: the male tool, the female tool and the composite sheet,

to optimize the process as well as possible. All these functions had to respect optimal safety conditions and environment. I had to take account of United Kingdom and Glasgow University roles.

III. DESIGN THE THERMOFORMING MACHINE

III.1. Technological solution research a) Conceptualisation: After having analysed the need, the step of post project was established. I tried to elaborate a functional product analysis. For that, the FAST diagram method was used, it answers to questions: how, when, why a function must be made. This method has drawn up the principal functions and secondly functions that the system has had to make. Thanks to an architectural sketch, I modeled the system. It did not give the solution but allows to study different mechanical liaisons between products. Then, an objectives tree method helped me to find any possible solutions. The analysis of each solution was made according to respected requirements and constraints.

Appendix 5: FAST diagram method


Fig.6: Male tool sketch

The last step was to find three best solutions. In a second part, the cost, the environment and the process criteria, allowed to choose the final solution. b) Studying the environment of the machine: A sketch of the main part (fig.6) was made to put ideas with first available elements. Tools can be fixed to a laboratory press. This one has used to experiment of resistance of beam elements so it has had a great load capacity (250,000N). The proximity of electric, pneumatic, hydraulic connections and water evacuation justified the choice this press. Then, I studied the setting-up of the different elements (e.g. dimension, stocking area and distance between connections) then I modeled them in CAD. These parameters were significant for the solution choice because they represented special and energetic constraints. Presentation of the envisaged process:

C) Development: preliminary calculation: The purpose was to make a preliminary calculation of tools. It had to take account of outside parameters (e.g. pressure, temperatures, humidity, conductivity). The most used Materials to build forming tools have been: aluminum, steel, and copper. However in analysing characteristics of each one, copper was about 50 times more expensive than steel. Consequently, only steel and aluminum was studied. A consolidation test had made at the university before this study. The pressure to consolidate a composite material sample (192mm X 102mm) was 70 bars. Therefore, after calculation two thicknesses were drawn up: 19mm with aluminum and 7mm with steel. The final choice of both material and thickness depended on the chosen process. d) Three possible process solutions: Here, the job consisted of choosing the best device which has realised for the station specifications. The problem was to find a means to change the temperature quickly. Thanks to an objectives tree method and a function/performance chart, three different solutions were found:

Composite Sheet

Heater element

Blank holder Female tool

Finished product

Heater element

Male tool

Press

Appendix 6: Calculation

Appendix 7: Classification of solutions


Compressor

Herter injector (off/on)

Tap water

Heater elements (off/on)

1) Hot or cold oil circulation: This solution required one or two tanks, a pump (or heater pump), a control valve and a regulator. It seemed perfectly adapting to our need allowing a fast and controlled heating and cooling. However, the number of parts and the technology looked an expensive concept.

2) Hot or cold air circulation:

This solution required: a compressor, a heater injector (or heater gun). We noticed that it answered well to the need with cheaper equipment. Nevertheless, the heating and cooling time were almost long because air is a very good insulator. Furthermore the equipment control was less accurate.

3) Material heating and introduction of cold water:

This third concept was only consisted by heating elements because the tap water has already been available. We observed that it was able to do expected characteristics with both quickly heating and cooling. Furthermore, it was easy to control and cheap. This preliminary study shown three solutions and allowed us to select one solution. The third case: material heating and introduction of cold water seemed to be the best, according to cost and technique while answering to the need. Thanks to the consultation of suppliers I could analyse more precisely the cost, then improved and established the final solution.

III.2. Consultation job a) To look for the equipment: The consultation of supplier lasted two weeks. Each solution was studied, detailed and assessed in consulting three suppliers for every element. The fact of looking for three suppliers allowed to have a clear and just idea of the proposed product in a minimum time. Thus it was easy to compare suppliers and negotiate because we has known enough information. This task was mainly made by mail, then in the second time by telephone. Two meetings were organized with the main suppliers concerning the heating and the cooling: Watlow Company (heater elements supplier) and Huber Company (supplier of systems: oil circulation). The need was detailed and we found the most adapted solution depending on proposed items. The consultation job required a precise following-up and a good organization to archive, classify, assess every suppliers according to solutions. For that, I used the Outlook and Excel software in order to draw up the wished query.

Appendix 8: Suppliers comparison


b) Financial study: After having consulted around thirty suppliers, an estimation of the price was calculated (NB. Here prices are without VAT and basic items were not accounted for):

1) Hot or cold oil circulation = £1,900 2) Hot) or Cold air circulation = £1,220 3) Heating material and introduction of cold water = £1,180

The second and third concept cost was quite closed; indeed there was just 3.2 % of difference compared to the entire cost. Considering of the system performance on the change in temperature, the third solution has chosen with the Watlow supplier. Consequently, the chosen material has been the aluminum because it does not oxidise upon contact with water.

III.3. Equipment choice a) Equipment: On September 26th, my supervisor, the Watlow Company and I had a meeting to study various technological heater solutions. We selected:

• Heater cartridges to increase the temperature of the material • Thermocouples sensors to measure the temperature • A radiant heater to the pre-heating the composite sheet • Controllers (PID) to control and fit the temperature

Further to this meeting, I mainly communicated by mail to know details and characteristics of each items. It was necessary to add to this equipment:

• Tubes and pipes resisting to high temperatures • Springs to compress and maintain the composite sheet in a good position • Waterproof seal resisting to high temperatures

b) First price estimation of the thermoforming station: At this point, it was important to have the price as accurate as possible to check if the available budget was sufficient. Indeed, the machine amount was £1,180 plus the additional elements cost which represented roughly 8 % of the machine price thus approximately £1,274. Consequently, the cost was higher than our £1,000. We needed to ask to an outside help to remedy to this over cost and buy the testing material (i.e. composite sheets and fabric)

III.4. Drawing and assembly At this moment the solution has known so I needed to draw different parts. The post project step was finished, I could go deeper into a study, and develops previously chosen technical solutions. a) Studying the software:

Appendix 10: Machine equipment

Appendix 9: Preliminary cost of the machine


To draw parts, the mechanical department has used the Solid Edge software. I had to get acquainted with this software before I could do the 3D drawings. My first work was to understand how the software works. For that, the progress which has been proposed by the tutorial was interesting in order to learn the drawing technique. After that, I could begin to model main parts like male and female tools. Secondly I studied how to assemble parts to create products. I applied my new knowledge to put together the thermoforming station parts. Finally, I continued to study how to draft with the tutorial because the definition layout and assembly drawing will be only given to the University workshop. b) Calculations: To have an accurate parts dimensions, calculations were necessary. The first one was to find the male and female tools thickness. Two thicknesses were possible according to the material as explaining previously. Aluminum was recommended because the water will be used. Consequently a 19 mm minimal thickness must be adopted. An important safety coefficient of 10 is applied to tools because they have put on a big load capacity press. It is usual to use a thin spherical shell under pressure calculations. For the design, I adopted a 20mm thickness. The second calculation was to determine the power to supply to tools in order to raise the temperature from approximately 20°C to 180°C. D uring the process, the equipment shouldl not exceed 150°C but by hypothesis I preferred to o ver size the power to achieve 180°C. After calculation, the equipment has required 1,290W to increase its temperature in 4 minutes and 345W to increase it in 15 minutes. It allowed me to select 4 heater cartridges of 300W each one provided by Watlow Company. Concerning tools, the last criterion to know was the water filling volume. By hypothesis, the filling time of tools had to be less than 30 seconds that it has been a correct time for our application. The flow rate of the used tap water has been to 4 liters per minute so the maximal capacity being adopted has been be to 2 liters. With the preliminary conception the filling time had been about 25 seconds that it was acceptable. Finally the last calculation was the blank holder surface. It depended on both male tool diameter and bean radius (i.e. 60 and 20mm). The result was a minimal surface of 194,834mm2 which represents a 442mm by 442mm dimension. As well these values have been equal to the composite sheet minimal dimensions. This calculation allowed me to draw forming machine parts surlier. C) Design description: These are main elements constituting the thermoforming station:

Cap

Male tool :

Radius=20mm

Radius=60mm

4 Heater cartridges

Thermocouple sensor

Outlet tube

Inlet tube

Appendix 6: Calculation


THERMOFORMING STATION

Tools are completely in aluminum. The heating is made by four cartridges of Ø6.5mm inside the wall and sat to 45°. Some water will be introduced to the inlet tube. It will circulate with a swirling movement inside tools thanks to a special shape and the tubes orientation. Finally it will go out to the outlet tube. Some under pressure air will be thrown into tubes to end up pushing water. Female tool:

To assure a good waterproof, O rings resisting to 250°C. (Supplier: Supra Seal) will be set between the cap and tools and as well around the heater cartridges. We will use copper tubes and pipes resisting to 200°C (supplier: Ficher) to run water. Furthermore 4 valves and tees will be useful to regulate the flow water and switch air/water tubes. The blank holder is constituted by two plaques which seal the composite sheet in horizontal position. The pressure maintaining device will be useful to apply and fit a uniform or asymmetric pressure depending on future tests. The thickness is 10mm for the upper plaque and 20 mm for the lower plaque. The blank holder will be put in an oven to achieve approximately 80°C. Then it will be sat on the female tool thanks to its conical shape machined in the down plaque. The device is massive to avoid to loss a lot of heat during manipulations. To guarantee that male and female tools should be line up, a specific tool was created. Moreover, an attaching system will allow to maintain the female tool on the press table.

Outlet tube 4 Heater cardridges

Inlet tube Thermocouple sensor

Blank holder

Lower plaque ferieure

4 maintain devices Upper plaque


III.5. Economical analysis and partnership Further to the design and consulting job, the cost of the thermoforming station was definitively known. It has been £1,465.65 with VAT and we had only have £1,000. Therefore, we had to be helped by the Don and Low Company specialized in the industrial textiles production because it had been interested by our researches. We convinced them that we needed additional funds and materials. a) Project presentation On September 7th, I presented formally our project to Don and Low by means of a Power point document. The future research step was explained with objectives to achieve. The company was interested and suggested to give a capital if necessary. Also, they could supply us pre-consolidated composite sheets or fabrics. Further to this meeting, I was in charge of communicating them the project progress. b) Solution: Cost sharing: The project over cost obliged us to find new funds. Consequently, I presented a document explaining our need. Dow and Low proposed financing a half of the machine cost which has been £750. Therefore, my task was to prepare two different orders package for the Watlow supplier which represents 62 % of the budget. However the delivery was made in one parcel to minimize the delivery costs. C) Project evolution and assessment: At the end of December, Don and Low Company came to appreciate the project progress. I presented the researches evolution and gave the work perspectives. The company provided us twenty pre-consolidated composite sheets and one fabric roll. People were satisfied and they told that they could give new additional funds to improve the machine and deepen our the research.

IV. MANUFACTURE AND ANALYSIS

IV.1. Manufacture and updating The parts manufacture began at the middle of November. When the draft of the main elements had finished, I supplied the definition and assembly layout to the Glasgow University workshop. It was better to explain to them the assembly detail, the expected process for the experiments, and at last the cautions to undertake. It allowed on one hand a better system comprehension and on the other hand to have advices on the conception. It was interesting to have a good communication with the workshop to resolve assembly problems and improve the prototype. My role was geared towards the following-up of the manufacture and the drawings updating. To do a quality work, drawings were updated during the manufacture progress by an iincreasing of indexes and the details modification. The progress was slow because two technicians had been sick for ten days. As well, the equipment delivery has been behind schedule for three weeks.

Appendix 10: Machine equipment

Appendix 12: Purchase of components

Appendix 11: Final machine cost


Better mesh

Quadratic element 10 partitions; 400 nodes

Coarse mesh

Tetrahedral element No partition

Final mesh

Quadratic element 10 partitions; 84,511 nodes

As I had a few work, I could simulation the parts behavior on a computer.

IV.2. Simulations The simulation allowed to check and to predict the parts behavior according to mechanical, thermal, electric criteria. For that, the Abaqus software from Dassault Systems was used because it has been compatible with Solid Edge software and preferment in simulations. However, it was difficult to use it but could be very realistic if data was correctly defined. Therefore, it was important to learn different exploitation possibilities on simple examples then latter I used my new knowledge to simulate machine parts. That’s why, I spent fortnight to study the using of the software by means of tutorials and manuals. Some simple examples were performed on mechanical and thermal simulations essentially. After, I continued my research by modeling ¼ of the male tool because of its symmetry and of the tri-dimensional result that I needed to obtain. a) Mechanical Simulations Several stages had to be correctly defined to have a result as near as the reality:

• Meshing sensitivity study: The meshing is useful to integrating geometry like a "skeleton" to perform numerical simulations. It is a method of finite element analysis which will be modeled with nodes, elements and meshing. The meshing will influence directly the quality and the precision of the result. The principle is to begin with a coarse meshing which will give a first approximate result with a global error. Then the meshing will be redefines depending on the geometry:

• Other elements to be defined:

Fig.8: Male tool Fig.9: Female tool

Appendix 13: Delivery of the raw material

Appendix 14 Manufacture

Appendix15: Mechanical simulations


Fig.10: 1/8 Male tool

When the meshing is correct, it is necessary to define: the material, interactions, the

integration strategy, boundary conditions, loads, and output requests. For this first study, the material was the aluminum T6 (70 GPa, 2700Kg / cm3, 0.33) and a 6.313 MPa uniform pressure was applied to the part bottom.

• Result: For the mechanical simulation, two aspects interested us particularly: the Von Mises constraints and the displacement. These results allowed me to check the design. The displacement was tiny and should engender no problem during forming of composite material. The gap between male and female tool was 2mm so this deformation represents less than one percent of the total gap. The maximum stress in the material is 30MPa which is much smaller than a 200MPa acceptable maximal constraint. The part should resist during experiments and should not have plastic deformation. b) Thermal Simulations: The purpose of the thermal simulation was to visualize the temperatures propagation and to predict the heat time. To have a pertinent result, it was necessary to limit the study to 1/8 of the part (fig.10) This hypothesis was made because of the part symmetry and allowed to put a cutting plan through the median plan of the heater element (i.e. one of 4 cartridges). Data:

• 160°C on a small area • Ambient air on the outside surface • Stable air inside the tool • Surface heat flux on the left side Geometrical constraints were applied because of the part partition: • On the top: Tz=0; Rx=0; Ry=0

Displacement:

Max displacement = 16µm

Von Mises constrain:

Max Von Mises stress = 30 MPa

Scale factor= 6.14 X 10+2

Appendix 16: Drawing up the thermal simulation

Appendix 17: Thermal Simulations


Fig. 11: Steady state response

Fig.12: Transient response Fig.13: Transient response

• On the left side: Ty=0; Rx=0; Rz=0 • On the right side: Tx1=0; Ry1=0; Rz1=0 (Change of datum)

Results: Two states were studied.

• A steady state response (fig.11): At the end of the process, that is to say when the temperature was stabilised. We obtained a temperatures propagation like on the right picture. The dark red part symbolises the cartridge position which gradually heated until 160°C. We noticed that the whole part is between 155°C and 160°C so a 5°C maximum range. However the outside surface was between 157°C and 158.5°C so a 2.5°C range. This small difference should not involve any consequences on the composite material forming.

• A transient response (fig.12 and 13):

At the end of 60 seconds, the outside surface temperature was between 152°C and 133°C. By extrapolation (Excel software), at less t han 4 minutes the part arrived to its stable state. Therefore the simulation allowed to check the previously established hypotheses of the design.




V. DISCOVERING OF A NEW ENVIRONMENT

V.1. Professional experience During these five placement months, I developed many technical skills. Indeed my project contained any creation and development steps of a product. These are the main acquired knowledge:

• Technological researches: the first task of the project consisted in finding out existing technology. I acquired a lot of information concerning the existing and future forming systems. For that, I visited a school and an industry working on these techniques. We could exchange our knowledge and ask pertinent questions. As well I deepened my researches in reading reports and general literature.

• Consultation and negotiation job: with the intention to find a cheaper and adapted equipment, it is necessary to list and examine many suppliers. It is essential to have a good organization to establish following-up documents depending on the queries. This consultation was mainly done on internet. Then, I needed to present my project, asked questions on the products characteristics, and asked quotations. This communication was established by mails, phone calls and meetings. The biggest difficulty was to call companies to exchange information. lastly, when the product was chosen, I filled the order which was faxed by the secretary.

• Conception and simulation: to design the machine, Solid Edge and Abaqus software were exploited. The first one is useful to draw parts in three dimensions then for making the draft. Also it has contained an assembly and animation module. The used software was quite similar to Catia software. Abaqus was more difficult to employ. A lot of options have been available and each step had to be defined correctly to have a result. Nevertheless it was perfectly adapted to the simulation and shown great approximation. Thanks to tutorials and manuals, I carried out more and more difficult examples then learnt the major part of options. My work focused on mechanical and thermal simulations. However it is possible to perform acoustics, fluid, electrical and mass distribution simulations as well.

• English technical vocabulary: during this project, I read technical documents, reports and articles. I learnt mechanics, thermal, computer vocabulary. The communication with the suppliers, the workshop, and teachers allowed me to improve my language. Moreover, the different presentations that I explained, has helped me to become more confident on a foreign language.

Beyond the project, I discovered a lot of interesting aspects, appropriate to Scotland and United Kingdom.

V.2. Cultural immersion Scotland has belonged to United Kingdom since 1707. This country counts around 5 millions habitants. The capital is Edinburgh but Glasgow is the biggest town of Scotland with 2.3 millions people. The official language is the English, however two languages: Scottish Gaelic and Scots which are recognised like a national language. Scotland is famous for these Islands (about 800), these lochs castels. My integration mainly took place in Glasgow where I did my project.


Fig.15: Lord Kelvin

Fig.18: Glasgow Cathedral

Fig.14: Kelvingrove museum

Fig.16 : Charles Rennie Mackintosh

Fig.17: Glasgow School of art

a) Visit of monuments:

• Museums and galleries: I visited most Glasgow museums. “Kelvingrove Art Gallery and Museum” (fig.14) is the most famous. Set up over three floors, we can see Scotland animals, art with magnificent pictures of the region and also of great famous painters. "The museum of transport" is also very interesting. It shows the United Kingdom motor history. We find inside every types of transport: boat, buses, trolley, cars, and motorbikes. The evolution of the motorcar is exhibited from the steam engine to the formula one. "Glasgow University" does not just use to the education. It hides some beautiful art gallery. It shows the scientific discoveries for future generations.

• Personality: Lord Kelvin (fig: 15): he started University at the age of 10, his father had been a professor of mathematics and was his teacher latter. He became a physics professor and had developed the thermodynamics in particular the second law of thermodynamics and Kelvin's scale of the absolute temperature. James Watt: he was born to GreenockIn in Scotland. He had improved the steam engine with the separated condensation room and designed a new steam locomotive. Robert Adam: is a Scottish architect and designer of the end of the 18th century, he has been famous for his classic and traditional building. His reputation has been international. John Boyd Dunlop: After his study at Edinburgh University, he had been veterinary surgeon for 10 years. Then he left to Belfast and invented the tyre. In 1888 Dunlop developed his own company which has known all over the world nowadays. Alexander Graham Bell: was born in Edinburgh in 1847, he became a physics professor at the Boston University (in USA) and invented the telephone in 1876. He became a naturalized American in 1882.

John Logie Baird was born in Helensburgh In 1888, he was an electrical engineering engineer from Glasgow University and he invented Television In 1926. He improved the image and created color television in 1928.

Charles Rennie Mackintosh (fig.16) was born on June 7th 1868 in Glasgow. He was an architect and a modern designer known over the world for his style called "Glasgow". He created the new school: Glasgow School of Art (fig.17) which has built up his reputation. Nowadays we can see many building of this style in Glasgow

• Glasgow Cathedral (fig 18): In Scotland, two religions are popular: Catholicism and Protestantism. “Glasgow cathedral” is the national church of the Scotland. One of the most medieval churches in Scotland which survived to 1560 reforms protected by citizens. Built in 1197, this catholic cathedral contains the St. Mungo tomb known as St Kentigern who is the


Fig.20: Glasgow rowing regatta

Fig.19 : World Pipe Band Championship

saint patron and founder of this cathedral. This massive architecture of 87m length, 20m wide, more than 32m high has closed magnificent vaults, big millennium stained glass windows, and an organ with a bewitching sound.

• Famous places: "Botanic Gardens": is a big park situated near the University. It was created in 1817. There are a lot of tropical plants and millennium plants from the whole world. There are an impressive glass building of 2137 m2 and large parks exhibiting many varied plantations.

“Glasgow Green Park”: is the oldest park of Glasgow, built in the 15eme century. It has known to welcome celebrated national and international events: concerts; the Great Scottish Run; the National Play Day (fig 19); the rowing regattas and the World Pipe Band Championship. b) Activity in my free time: The Scotland weather is not favorable to outside activities. However being an addict of sport, I joined to the Glasgow University sports association. At the University open day, I could practice the rowing which is a popular sport in United Kingdom. I did not have expected to train with one of the strongest team of Scotland. Therefore I preferred to be with the beginners because I had been too busy. I enjoyed to row with them because the atmosphere was very pleasant in spite of execrable climatic conditions. The club lent me a cycle to travel and I could visit Scotland country side which has been really wonderful. Mountains are not high but steep and the flora is very green. With the rowing team we participated in two races. The first one was in the North of the country to Inverness, which was the most difficult races because there were hail, cold, rain and wind. The second one took place at the beginning of December to Glasgow (fig 20) and the weather was nicer. I could improve the rowing and acquire a specific vocabulary Except sport, I spent evenings with four flatmates from Ireland, England and Korea. As well we had long discussions about our origins, habits and activities. It was very enriching. C) English courses: To improve my English and allow a better integration, I took English classes from the middle of August to the middle of December. It took place from 7:30 pm to 9 pm two evenings a week. In November, I had extra classes two hours a day. I had been learning a lot of expressions, correcting mistakes and practicing pronunciation. It was very interesting and allowed to meet people from many countries.


VI. CONCLUSION

VI.1. Final result project The design of a new machine is not an easy task and requires a great organization. I completed 80% of the objectives. Currently it remains to perform experiments at the beginning of January and to compare the theory to the practical result. The thermoforming station is ready, although there are two weeks late because of a long equipment delivery time and workshop problems. The first activity was the solution research. When I had known information about how to manufacture composite parts, I chose to heat aluminum and cool it in introducing tap water. This solution satisfied the need in terms of functions and cost. The simulation allowed to check established hypotheses of the design and to prove the tools resistance. Furthermore, I could predict the temperatures propagation during the process and assure to achieve to 160°C on the outside tools surface in less than 4 minutes. The machine cost corresponds to the budget thanks to the financial help from Don and Low Company. Now the remaining budget is £250 and the company plans new funds to improve the design to perform future experiments. The project remaining is to experiment and improve the thermoforming process and highlights results. Two students will be in charge of perfecting the prototype: one working on a manipulation automatic system of the radiant heater and the other hand on making an auto-heater blank holder. They can experiment more accurately.

VI.2. Personal contribution The project contains any design and development steps of a product. The research to the best solution, the cost analysis, simulations taught me much knowledge. I know well two new software and improve my English technical vocabulary. I have skills required to work with foreign companies. Difficulties were often met, but I always knew how to remedy it successfully. I am more assured in my own abilities and more confident about difficult and unusual tasks. These five placement months have allowed me to get an open mind. I met people of different origins and we had shared our experiences. My English is better and I can speak easily although I still meet some difficulties to understanding especially with the different British regions accents. During this period, I discovered Scottish habits and specialties through food, landscapes, and traditions. Sightsee, the Scottish history learning, and walks in the country side occupied my free time. To be able to do a trip in a foreign country is really fabulous. It offers another vision of the world, and allows to change your mind. It is sure, I am going to regret I cannot stay longer in this wonderful country.

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