Developing a Process for Laminated Object Manufacturing (Rapid Prototyping) Without de-cubing.

Topic - Development of a process for Laminated Object Manufacturing

without de-cubing.

Course – BEng Honours Mechanical Engineering Technology

Name – Sree Vishnu MuralidharanSupervisor – Dr. Dele Owodunni

Date – 27th April, 2012

Final Year Project

April 1, 2012

Abstract

The laminated object manufacturing (LOM) process is an effective rapid prototyping

technology with a variety of possible applications. The main process of the LOM consists of

at first, a slice material such as paper is transported onto the work table, the work table raise,

and then a hot beam press and heat up s the shape into small piece in order to wipe them off

after build all layers; after cutting is finished, the work table fall and repeat the first step. An

alternate method is to collect all the cut layers of the prototype first and then stacking is done

layer by layer with gluing them properly.

As rapid prototyping also includes developing complex prototypes, LOM being a

rapid prototyping process face difficulties in making complex prototypes as a cubing method

is used to support prototype being made. But the cubes cannot support the overhanging or

island structures in the prototype due to its structure. The removal process of cubes known as

de-cubing is tedious, time consuming, labor intensive and also causes damages to the

prototype during its removal. The LOM process here is developed by adopting powder as the

support material eliminating the de-cubing method, as powder provides support to the

prototype being made and also the overhanging structures in it. Two complex prototypes have

been made and compare with the current Rapid prototyping technologies proving this process

to be cost effective and time efficient.

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Acknowledgement

I most humbly surrender with gratitude before my esquire professor Dr. Dele

Owodunni who is my guiding inspiration who awaked my sub conscious mind & engineering

talents through the inspiration, sincerity, spending precious time & imparting knowledge

presenting a success system before which difficulties, failures & obstacles are powerless but

stepping stones to success under extra stress. My professor taught me to relentlessly work

hard under pressure to improve my capacity which I understand is incredible, formidable &

impossible. Circumstances cannot change us but we can change the circumstance forgetting

physical & mental pains to achieve the goal accurately within time with zero tolerance with

genuine desire for success and inspiration.

My emeritus professor changed my negative attitude to positive result oriented action

with preference directing me to understanding, acceptance & direction.

I express my genuine gratitude to staff & lab technicians for their co-operation. I am much

delighted and obliged to this campus, lab & immaculate library, multicultural but friendly

colleagues. By changing the attitude we can change the life for positive results.

I have boundless love & obligation to my parents for arranging me education in this esteemed

& prestigious Greenwich University. I am proud of being a student of a prestigious

institution.

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Table of Contents

Abstract.................................................................................................................................................2

Acknowledgement.................................................................................................................................3

Chapter 1...............................................................................................................................................8

Introduction.......................................................................................................................................8

1.1 The main purpose (Aim):.............................................................................................................9

1.2 Objectives:...................................................................................................................................9

1.3 Deliverables –..............................................................................................................................9

Chapter Two........................................................................................................................................10

Background Concepts......................................................................................................................10

2.0 Rapid Prototyping and its types.................................................................................................10

2.1 RP uses –...................................................................................................................................12

2.2 Rapid prototyping technologies –..............................................................................................14

2.3 Rapid Prototyping Pros and Cons-.............................................................................................17

2.4 The different Rapid Technologies –...........................................................................................18

2.4.1 Stereolithography................................................................................................................19

2.4.2 Selective laser sintering –...................................................................................................21

2.4.3 Laminated object manufacturing (LOM)............................................................................23

2.4.4 Three-dimensional printing.................................................................................................25

2.5 The Laser cutting machine used for cutting the layers –............................................................29

2.5.1 Purex - Fume extraction system..............................................................................................30

Chapter Three......................................................................................................................................32

Problem analysis and solution.........................................................................................................32

3.1 Problem analysis -.....................................................................................................................32

3.1.1 De-cubing in laminated object manufacturing –.................................................................32

3.1.2 Supporting the overhanging structures –.............................................................................33

3.1.3 Alignment of the paper sheets–...........................................................................................34

3.2 Solution –.............................................................................................................................34

3.2.1 Solution replacing the cubing method of supporting...........................................................34

3.2.2 Supporting the island structures –.......................................................................................34

3.2.3 Paper alignment mechanism –............................................................................................34

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Methodology.......................................................................................................................................35

Chapter four.........................................................................................................................................36

Implementing the solution...............................................................................................................36

4.1 Eliminating de-cubing and adopting powder as support –.........................................................36

4.2 Adapting technologies/methods used by other Rapid Prototyping systems –..........................37

4.2.1 3D Printing.........................................................................................................................37

4.2.2 SLS (Selective Laser Sintering)..........................................................................................40

4.3 Powder Selection –....................................................................................................................42

4.4The Selection of method of deposition of powder into chamber –..............................................43

4.5 Alignment Mechanism of paper sheets –...................................................................................45

4.5. Prototypes to be made –........................................................................................................47

4.5.1 Cutting the papers to obtain the paper with correct thickness to get exact dimensional accuracy of prototype–................................................................................................................49

4.6 Stacking of papers –...................................................................................................................63

4.7 Prototype made –.......................................................................................................................63

4.7.1 The turbine (impellor) prototype –......................................................................................63

4.7.2 The Motorbike prototype –.................................................................................................65

4.8 Supporting the island structures –..............................................................................................66

Chapter 5.............................................................................................................................................67

Results and Discussion....................................................................................................................67

5.1 The prototypes made..................................................................................................................67

5.1.1 The turbine prototype........................................................................................................67

5.1.2 The Motorbike prototype...................................................................................................67

5.2 Dimensional comparison of the CAD model of turbine and the prototype:-..............................68

5.2.1 Graphical Representation of quality of manually made turbine prototype and the turbine of proper dimensions.......................................................................................................69

5.3 Supporting the island structure............................................................................................69

5.4 Comparison of dimensional accuracy of motorbike made in 3D printing machine and Motorbike made by Laminated Object Manufacturing (L.O.M) –...................................................70

5.4.1 Variations in dimensions of motorbike made by 3d printing and motorbike by L.O.M......71

5.4.2 The Time comparison in case of Motorbike built by 3d printing and LOM........................72

5.4.3 Cost Comparison in case of Motorbike built by 3d printing and Laminated Object Manufacturing (L.O.M)-..............................................................................................................73

5.5 A comparison of manually made prototype with the prototype made by 3d printing –........74

Chapter 6.............................................................................................................................................75

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Conclusion and Future work –.........................................................................................................75

Conclusion.......................................................................................................................................75

Future Work –.................................................................................................................................75

Reference............................................................................................................................................76

Appendix.............................................................................................................................................83

List of Figures –

Figure 2.1 Rapid Prototyping chart..........................................................................................11

Figure 2.2 Result of introducing rapid prototyping in design..................................................12

Figure 2.3 the three stages of rapid prototyping system...........................................................13

Figure 2.4 Classification of different rapid prototyping systems.............................................17

Figure 1.5 Stereolithography machine.....................................................................................18

Figure 2.6 Method of Stereolithography..................................................................................19

Figure 2.7 Selective Laser Sintering Machine.........................................................................20

Figure 2.8 Selective Laser Sintering method...........................................................................21

Figure 2.9 A Helisys LOM machine........................................................................................22

Figure 2.10 Method of LOM (laminated object manufacturing process)................................23

Figure 2.11 3D printing machine.............................................................................................24

Figure 2.12 3D printing process...............................................................................................24

Figure 2.13 a roller layering powder over powder bed in 3D printing

process.........................25

Figure 2.14 Comparison of different Rapid Prototyping Technologies...................................26

Figure 2.15 Material comparison

charts....................................................................................27

Figure 2.16 the laser cutting machine......................................................................................28

Figure 2.17 fume extraction system.........................................................................................29

Figure 3.1 The de-cubing method……………..………………………………………..……32

Figure 3.2 an overhanging structure………...………………………………………………..33

Figure 3.3 (a) An object (b) the diagram showing the overhanging structure in the object to be

support………………………………………………………………………………………....3

3

Figure 4.1 A complex prototype made by sintering nylon powder…..……………………...35

Figure 4.2 the process of depositing powder in 3d printing technology…..………………...36

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Figure 4.3 A layer of powder being spread by roller………………………………………...37

Figure 4.4Binder solution being deposited by the binder cartilage…………………………..37

Figure 4.5 Roller depositing another layer of powder over the previous one………………..38

Figure 4.6 the whole process of 3d printing at a glance……………………………..……….38

Figure 4.7 a selective laser sintering machine………………………………………………..39

Figure 4.8 the selective laser sintering process………………………………………………40

Figure 4.9 a scraper blade pushing the powder………………………….……………………………………….42

Figure 4.10 a scraper blade pushing the powder…………………………………………………………………42

Figure 4.11 the roller pushing (rolling) forward powder……………………….…………………………….43

Figure 4.12 the roller pushing the powder…………………………………………..……….43

Figure 4.13 Slice directions in paper alignment mechanism…………………………………44

Figure 4.14 Object dimension…………………………………………………….………….44

Figure 4.15 slicing of the object……………………………………………………….……..45

Figure 4.16 paper alignment mechanisms……………………………………………………45

Figure 4.15 slicing of the object……………………………………………………….…..…45

Figure 4.16 Turbine (impellor)…………………………………………………………….…46

Figure 4.17 gear (Differential)……………………………………………………………….46

Figure 4.18 Snarl……………………………………………………………………………..46

Figure 4.19 motorbike………………………………………………………………………..47

Figure 4.20 Pen Holder……………………………………………………………………....47

Figure 4.21 the laser cutting machine powder…………………………………………….…48

Figure 4.22 the laser cutter powder………………………………………………………….48

Figure 4.23 paper thickness of 0.10 being cut to make turbine………………………………49

Figure 4.24 paper thickness of 0.20 being scored to make turbine…………………………..49

Figure 4.25 sticky paper of thickness 0.15 mm to make turbine…………………………….50

Figure 4.26 Top view of turbine……………………………………………………………...50

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Figure 4.27 Wiper being used to push powder across build platform………………………..51

Figure 4.28 roller used for pressing the stacked layers……………………………………....51

Figure 4.29 paper alignment through nails placed on platform……………………………...52

Figure 4.30 Prototype being made using sticky papers of 0.15 mm thickness………………52

Figure 4.31 Side view of turbine……………………………………………………………..53

Figure 4.32 bottom view of the turbine……………………………………………………....53

Figure 4.33 paper thickness of 0.15mm thickness being cut by laser……………………..…54

Figure 4.34 paper thickness of 0.05 adjusted in laser cutting machine being cut by laser…..55

Figure 4.35 Thickness of paper 0.15 mm and 0.08 thickness adjustment made in

machine....................................................................................................................................56

Figure 4.36 Thickness of paper 0.20 mm and 0.06 thickness adjustment made in

machine....................................................................................................................................57

Figure 4.37 Thickness of paper 0.20 mm and power 20% adjustment made in machine……58

Figure 4.38 papers being stacked, scoring done by the laser………………………………...59

Figure 4.39 thickness of 0.30 mm and power 16% adjusted in laser cutting machine………60

Figure 4.40 thickness of 0.22 mm……………………………………………………………61

Figure 4.41 turbine prototype -front view……………………………………………………62

Figure 4.42 turbine prototype -back view……………………………………………………63

Figure 4.43 turbine prototype -top view……………………………………………………...63

Figure 4.44 Motorbike prototype - top view…………………………………………………64

Figure 4.45 Motorbike prototype - front view……………………………………………….64

Figure 4.46 prototype made by 3d printing…………………………………………………..65

Figure 5.1 Turbine prototype made by LOM without de-cubing…………………………….66

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Figure 5.2 Motorbike prototype made by LOM without de-cubing………………………….66

Figure 5.3 turbine CAD model……………………………………………………………….67

Figure 5.4 turbine prototype made by LOM without de-cubing……………………………..67

List of tables

Table 2.1 the Emergence of Rapid Prototyping……………………..……………………….10

Table 4.1 Selection of paper and proper parameters to make turbine………………………..50

Table 5.1 dimensional comparison of Turbine CAD model and turbine made by LOM….....68

Table 5.2 dimensional comparison of motorbike made by 3d printing and LOM…………...69

List of Graphs –

Graph 5.1 dimensional comparisons of Turbine CAD model and turbine made by LOM……

68

Graph 5.2 dimensional comparison of motorbike made by 3d printing and LOM…………..70

Graph 5.3 Comparison of time taken for motorbike made by 3d printing and LOM………..71

Graph 5.4 Cost comparison of motorbike made by 3d printing and LOM…………………..72

Graph 5.5 Quality, Cost and Time comparison of Prototype made by 3D Printing and

L.O.M………………………………………………………………………………………...73

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Chapter 1

Introduction

The Laminated Object Manufacturing is the process which builds and layers

three dimensional objects with the help of process like binding and fusing layers of

paper or other materials that are brought into a new layered shape by laser without

waste of material and accuracy. The layers which are rested on the platform was

supported by cubes which were then de-cubed, but as this process is time consuming,

tedious and damage causing and mainly restricts the manufacture of complicated

prototype as the cubes could be done in island and overhanging structures in complex

prototypes, thus a new machine with proper support material and a process is to be

developed in this project so that any type of complex prototype can be made using the

Laminated Object Manufacturing process.

The Process of Laminated Object Manufacturing –

The Laminated Object Manufacturing is the process which consist of laser (or

cutter), heated roller, a support, a platform, and a roll of paper or material used for

making prototype.

The process starts with a paper material which is brought onto a work table,

the work table then tend to rise. The paper or the material is brought in-front of laser

such that the laser cuts the paper or material layer by layer. These layers have

adhesives underneath it or could be applied under it so that they are stacked after they

are cut (cut and bond process). After cutting each layer the build platform goes down

and the layer comes on for it to be cut. As these layers cannot be made into a

prototype in air without any support, thus they were supported by cubes and after the

whole process of cutting was over the build platform is made to rise above and the

prototype is taken after the time consuming and tedious de-cubing process.

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1.1 The main purpose (Aim):

The purpose of this project is to develop a process for the laminated object

manufacturing without the process of de-cubing. Thus, the main aim is to develop the

process to create any type of complex prototype using the Laminated Object

Manufacturing process without de-cubing.

1.2 Objectives:

Getting knowledge of Laminated Object Manufacturing (L.O.M) and the

theory on it.

Developing the process to show the prototype can be created without the de-

cubing process in Laminated Object Manufacturing.

Developing the process to save time and cost and making the prototype with

proper accuracy.

Making complex prototypes with proper accuracy using the methods that will

save time and be cost effective.

Finding and applying the methods to support island objects or overhanging

structures in complex prototypes.

1.3 Deliverables –

To provide a cost effective method of making prototypes

To provide a process that is time consuming when compared to the current

Laminated Object Manufacturing process and other rapid prototyping

processes

A report regarding the problems, solution, the methods of solving the

problems and the comparison of the prototype being made with that of other

rapid prototyping systems

A log book with updated research details and changes made in the project

methodology.

A poster describing the project at a glance

Complex prototypes to show prototypes that are complex in nature can be

built without the process of de-cubing.

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Chapter TwoBackground Concepts

2.0 Rapid Prototyping and its types

Need and Scope of Present Work -

Rapid prototyping was formed in 1986, but since its invention many techniques

related to rapid prototyping have been established in the commercial world. Rapid

prototyping are used to make the physical objects from the CAD models and have different

names such as – Addictive manufacturing, solid freeform fabrication, addictive fabrication,

layered manufacturing and three dimensional printing. The Rapid prototyping offers a range

of advantages when compared to the subtractive fabrication technologies –

Any complex object can be created.

It manufactures the complex prototype in a fast process and is easily manageable and

straightforward.

Table 1

Year of Inception Technology

1770 Mechanisation

1946 First Computer

1952 First numerical control (NC) machine tool

1960 First Commercial laser

1961 First commercial Robot

1963 First Interactive Graphics system

1988 First commercial Rapid prototyping system

Table 2.1 the Emergence of Rapid Prototyping [1]

Wax and resins are the raw materials that are used by some of the techniques in

included in rapid prototyping. The functional testing mostly results in less mechanical

strength and therefore it becomes a barrier for the rapid prototyping. The Rapid prototyping

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technology has now opted to stop forming prototype only for visualisation; rather it focuses

on the “form-fit-functional” approach to have a better future in rapid manufacturing. Rapid

prototyping now uses the direct metal deposition methods worldwide to overcome these

problems. Some technologies use lasers or electron beam technology in melting the metal

known as Solid Freeform Fabrication (SFF). These technologies build slowly and are also

expensive. Welding is one of the methods which was much before rapid prototyping and has

been regarded as a solution to be used in the layered manufacturing process as a cost effective

way. 3D welding does not give or proper dimensional accuracy and surface quality in spite of

all the developments and improvements being made with regard to it.

Figure 2.1 Rapid Prototyping chart [1]

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Rapid tooling is a process of making the components which doesn’t require

conventional tolling and also it does require labours who are skilled model makers.

Subtractive manufacturing process achieves the final shape by removing the parts of the

material for modifying the object. The RP components are made layer by layer until the

object is manufactured. This can also be built by different RP processes.

Rapid prototyping starts with a 3D CAD model where any object is made using the

techniques involved in rapid prototyping technologies. Rapid prototyping is also a helpful

thing in medication as it is used in MRI. The source doesn’t matter in rapid prototyping; it

requires a STL file and then is sliced horizontally. The sliced things (papers sheets or metal

sheets) are stacked together and are cut for a proper design of the material which is to be

obtained and is finally stacked to form the object with respect to the CAD model of the STL

file.

2.1 RP uses –

The uses of Rapid Prototyping are –

Concept Models –

Rapid technologies are used to make any complex shaped object in a quicker way

and cheap way. If any correction is to be made before the manufacture of the object, changes

or necessary modifications could be made to the object in order to attain proper object. Even

the RP parts can be distributed to the sales team in order to have feedback of it from the

customers.

Final or semi functional Components –

The Rapid prototype parts doesn’t have the physical properties to make the final

functional part, thus the semi-functional parts are made by rapid prototyping. Rapid

prototyping can be used as assemblies which forms final function. The semi functional parts

can be brought together and experimental tests can be done on the basis of the geometry of

the part and not on the material properties.

Mater patterns –

Rapid prototyping are used to make production tooling. They are used as masters in

sand casting foundries, investment casting moulds. By the usage of reaction injection

moulding process or vacuum moulding, silicon rubber moulds for low volume of functional

parts can be produced with the help of rapid prototyping.

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Direct tooling –

There is soft tooling and hard tooling. The low production volume is made from soft

tooling where it’s made from polymers. The hard tooling is done by new RP process like the

injection moulding tooling is made in metal composites where one million shots are being

done.

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Figure 2.2 Result of introducing rapid prototyping in design [2]

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2.2 Rapid prototyping technologies –

The Rapid prototype technology changes as time goes on with its modernization and

high advancement done in it. There are five processes which is taking place at present –

Sintering Process – Sintering process is the process where the heat source is used to

sinter the powder. The process involves a laser beam to do so.

Curing Process – The polymer is hardened in this case by exposing the photo sensitive

polymer to a light source.

Binding Process - The powder is bind in this process by depositing liquid binder onto

a powdered material

Sheet Process – The sheets are cut into shapes of the design and then stacked (cut then

bond process), it also follows a process of stacking the paper sheets and then cutting it

(bond then cut process)

Dispensing process - In this process the metal is melted and is deposited as hot

filament or as individual droplets.

Figure 2.3 the three stages of rapid prototyping system [3]

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RP systems listed in 1999:-

3DP three-dimensional printing

3DWM three-dimensional welding and milling

BPM ballistic particle manufacture

CAM-LEM computer aided manufacturing – laminated engineering materials

CLOM curved laminated object manufacturing

DLF direct light fabrication

DLMS direct laser metal sintering

ECLD-SFF electrochemical liquid deposition for solid freeform fabrication

EDSSM extrusion and deposition of semi-solid metals

EFF extrusion free forming

EPDFF electrophotographic powder deposition for freeform fabrication

FDC fused deposition of ceramics

FDM fused deposition modelling

FDMet fused deposition of metals

FFF fast freeform fabrication

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FI fast inkjet

LDM laser diode manufacturing

LENS laser engineered net shape

LM layered manufacture

LOM laminated object manufacturing

M2SLS multi material selective laser sintering

Meso SDM mesoscopic shape deposition manufacturing

PPD point wise powder deposition

RPBPS rapid pattern based powder sintering

RSLA refrigerative stereolithography

SGC solid ground curing

SLA stereolithography

SLPR selective laser powder remelting

SLS selective laser sintering

TIF temperature induced forming

TLP thick layer prototyping

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2.3 Rapid Prototyping Pros and Cons-

Rapid prototyping creates complex prototypes of any shapes due the advancement in their

manufacturing and planning process which is automated. They create three dimensional

prototypes which helps the designers to create any three dimensional prototypes rather than

opting the two dimensional one.

Pro’s related to Rapid Prototyping –

Designers can work on rapid prototyping in a faster and cost effective way.

Speedy improvements in design

It can test any physical object of any complexity in a very short period of time

Product sales increases

It minimizes the time consuming discussions and evaluations involved in

manufacturing possibilities.

Can eliminate from the design in a quicker way

Increase in the speed of system development

Reduces the labour in terms of manufacturing

Quick modification of design

Involvement of customer at early stages

Product testing is very quick

Parts that are made by rapid prototyping show great time, cost and material savings.

Cons related to Rapid Prototyping –

There are some challenges that are faced by rapid prototyping which should be

overcome

Other design ideas could be excluded if manufacturing is takes place quickly

Design features are limited due to less scope of prototyping tool.

The optimization of the programme could be hampered if there is too much of

involvement

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2.4 The different Rapid Technologies –

Figure 2.4 Classification of different rapid prototyping systems [2]

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2.4.1 Stereolithography It is one of the oldest rapid prototyping technologies being started in 1980’s. It is

short formed as SLA and can develop prototypes of complex shapes with a good surface

finish when compared to other machines. It is a process which creates cross sections of a 3D

object within space of liquid photopolymer using ultra violet laser. It builds layers ranging

from 0.004 inches to 0.006 inches. The SLA is used as masters for the production of silicon

moulds and reaction injection moulding.

Figure 6.5 Stereolithography machine [4]

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Method-

The part is built on a platform where a vat of polymer is there, the platform rises and falls

within the vat. The movement of the platform takes place when it’s below the surface of

liquid polymer. The cross section of one slice is then traced by the laser which results in

solidification of the polymer as the laser hits it. The next layer of is traced when it moves

down the one slice (0.050 – 0.250mm) and then moves to the fresh layer of liquid polymer.

When the laser traces out the other layers it sits on the previous layers as the process

continues. After the process is completed i.e. when all slices are traced by the laser the

platform is taken out and the excess liquid polymer is removed or cleaned off. An ultraviolet

oven is final part which remains after the removal of the waste.

Figure 2.6 Method of Stereolithography [5]

Advantages of Stereolithography -

Good surface finish

Easily obtained

Good accuracy of the geometry in general

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Disadvantages –

Support structures are needed to support the model and also contain the removal

process.

Resins and acrylate should be used to wrap the parts

Resins need to be handled carefully as they are hazardous

2.4.2 Selective laser sintering – The selective laser sintering (SLS) helps to make the most complex and small

function parts with the help of powder as a support material. The SLS process which involves

the metal powder can be used for making production tooling.

Figure 7.7 Selective Laser Sintering Machine [6]

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Method –

In the Selective laser sintering (SLS) system, a thin layer of powder is spread over the built

platform using a roller mechanism. The powder changes into a solid form after it is fused by

the laser as it heats it just below its melting point. The sliced part is cut and rests on the

previous one. The un-sintered material settles as support material for it and after the process

is complete, it can be removed.

Figure 2.8 Selective Laser Sintering method [7]

Advantages –

Achieves accuracy

Good Surface Finish

Additional support structures are not required to build the parts

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Disadvantages

Surface finish could be poor

Requires post curing

Limited Materials

The machines could take long time for heating and then cooling down.

2.4.3 Laminated object manufacturing (LOM)

The Laminated Object Manufacturing (LOM) system was introduced in 1991

by Helisys, CA. The mechanism of the system starts with a sheet placed over a build

platform, a laser to cut the sheets in the designed way as in the CAD model or in the STL file,

a roller to put pressure on the sheets on the previous one which is cut by applying glue in

between the sheets or using adhesive coated sheets so as to stack the layers properly. After

the completion of cutting each layer the built platform lowers and then the new layer of sheet

again sits on the previous one and the process continues. After the layers are cut the waste

material around it supports the model and can be removed once the model is built. LOM is

one of the cheapest systems in Rapid Prototyping to make parts of complex geometry.

Figure 2.9 A Helisys LOM machine [8]

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Method -

The process starts with the paper sheet being rolled over and is cut by a laser or a cutter and

then similarly another paper sheet is rolled and is cut according to the design and stacked

over to the previous one. The waste material around the final object is removed by a process

called de-cubing which is time consuming and tedious.

The surface finish, stability and accuracy of the paper are not better when compared with

other rapid prototyping systems. One of the benefits is that they can be built by easily

available materials. As there are limitations on materials such as plastics, ceramics, metals

and composites are used for this work.

Variations have been cited by many companies in case of the LOM system as many

companies use different cutting methods, Kara Corp. uses knife to cut the layers in place of

lasers and Solidi 3d ltd. uses knife to cut the layers but uses a solvent to stack the layers of

plastic film.

Figure 2.10 Method of LOM (laminated object manufacturing process) [9]

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Advantages of LOM –

Low maintenance cost

Low labour cost

It has high durability

It possess low brittleness

Parts can be made of variety of materials

Disadvantages

Supports are needed for the models being made

Poor surface finish

Difficulty in producing hollow parts

Difficulty in supporting overhanging structures

2.4.4 Three-dimensional printingIt is the latest technique developed by Massachusetts Institute of technology (MIT). Z

Corporation and Pro Metal took its license for prototyping applications and tooling

respectively. 3D printing technology is an addictive manufacturing technology that was

based from a rapid prototyping technique known as stereolithography.

Figure 2.11 3d printing machine [10]

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Method –

This method starts with the spreading of the powder layer by layer over the surface of

powder bed. As in ink jet printing, the place where the object is formed is due to the joining

of binding material and particles. A roller mechanism layers the powder on the platform and a

piston mechanism lowers the powder bed so that other layers can be layered increasing the

layers upon each other. This process of layering on each other is continued until the object is

completed.

Figure 2.12 3D printing process [11]

Figure 2.13 a roller layering powder over powder bed in 3D printing process [12]

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Advantages –

It has strong build up compared to other rapid prototyping systems

Complex shapes or objects can be created as they don’t require support structures

Disadvantages-

Surface finish is not good

The parts that are newly printed are fragile and require infiltration

Figure 2.14 Comparison of different Rapid Prototyping Technologies [13]

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The chart shows materials that are offered by Xpress 3d. Ratings are given on the basis of application and uses. -

Figure 2.15 Material comparison chart [14]

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2.5 The Laser cutting machine used for cutting the layers –

Figure 2.16 the laser cutting machine [15]

The benefits of Universal’s laser systems –

The laser traces objects with a print control and is software controlled.

It can cut, score, mark, and produce photo images in a single step.

Without applying any physical force the material can be modified.

It has capacity to produce everything in the needed time and doesn’t require waiting

for hard tooling.

The Universal laser system have excellent quality beam which has power distribution

and good near and far field characteristics which is unique in their laser systems due

to the air cooled and free space gas slab lasers.

The laser has the power and potential to even trace out or cut the small spots because

of the high power density optics in it.

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The laser system has a material based driver which traces or cuts the material

according to the thickness that is being entered.

2.5.1 Purex - Fume extraction system: –

Figure 2.17 fume extraction system [16]

Specifications of the fume extraction system -

Voltage = 230 volt

Rated Power = 1800 watt

Frequency = 50-60 Hz

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Benefits of fume extraction system –

It can maintain constant extraction rate even if the filter blocks as it is equipped with

automatic flow control.

It can adjust the speed.

During the time exhaust it can sense gas and particles.

Capital costs and running costs are low

It is equipped with carbon filters to remove the harmful gas

Quite operation

The fumes generated from the laser cutting machine when tracing out or cutting anything

may lead to problems for the humans like asthma attacks or other respiratory diseases. Thus a

fume extractor must be used so as to extract the fumes. The following are the functions that re

done by the fume extraction system –

Protect the health of employee

Offers good working environment

Increases the speed of production

Reduces the wastes and dust materials so that the complaint by the customers or the

operators is reduced.

Reduces the cost and time required for cleaning the laser senses, conveyors, soldering

machines and other equipment

Increases the speed of production

Types of extraction system -

External Extraction system – pumps the contaminated air outside the area.

Internal extraction system – Captures and filters the air and has (local exhaust

ventilation) LEV

LEV is the best system and is used in this process as it captures the fumes there itself, filters

it and doesn’t allow the fumes to flow in outside area.

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Chapter Three

Problem analysis and solutionChapter Three gives description on the problems that are faced by current Laminated Object

Manufacturing method of de-cubing, some other issues related to it and the proposed solution

being suggested for the problem

3.1 Problem analysis -

The Laminated Object Manufacturing faces mainly two problems –

De-cubing - (Removal of waste materials after completion of process)

Providing supports for island or overhanging structures in complex prototype

Alignment of the paper sheets

3.1.1 De-cubing in laminated object manufacturing – The removal of waste material process in the laminated object manufacturing is

known as De-cubing.

De-cubing process-

Removal of the stack from the platform of the machine

To expose the cubes of the excess material (waste material), the surrounding wall is

removed.

Removal of cubes from the surface of the parts

Figure 8.1 the de-cubing method [17]

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The process of de-cubing is labour intensive, time consuming and tedious process Laminated

Object Manufacturing (LOM). The waste materials is not only strong as the final made part

by LOM, it gets stick to the part. De-cubing is more complex due to the location and the size

of the material. The waste material when trapped between the walls, blind holes, internal

cavities with restricted areas etc. makes it much more difficult.

3.1.2 Supporting the overhanging structures –

Figure 3.2 an overhanging structure [18]

Figure 3.3 (a) An object (b) the diagram showing the overhanging structure in the object to be supported [19]

The island structures inside and outside the object to be prototyped should be supported as

they are linked to the object. If the supports are not given the prototype cannot be completed

as the island structure cannot be built as its hanging.

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3.1.3 Alignment of the paper sheets– The paper sheets if not aligned properly will result in zero accuracy and no surface finish and

a failure in making the prototype with respect to the design.

3.2 Solution –

3.2.1 Solution replacing the cubing method of supporting

De-cubing being one of the most tedious, time consuming and labour intensive

method should be replaced with other method of supports that could provide a firm support to

the object being manufactured and can also be easily removed. Rapid prototyping

technologies like 3D Printing and Selective Laser Sintering uses powder deposition method

by a roller and forms objects. Thus adapting the technology in Laminated Object

Manufacturing is found as the solution to eliminate the de-cubing method. Application of

powder around and in the holes, in cavities, between the walls of the object won’t cause any

problem in neither in deposition nor in the removal process. Thus replacing the powder with

the current de-cubing method will be the ultimate solution for supporting the object. The

powder can be easily deposited and removed.

3.2.2 Supporting the island structures –

The need for supporting the island structures is needed so as to make the prototype

correctly according to the design. The solution for supporting the structure is by supporting

the island or overhanging structures with sticky – label type papers rolled under it so that

when rolled on, its upper part sticks on to the under surface of the island object and the lower

part of the paper roll rests on the bed firmly. The island could be easily removed and can be

relied upon to have objects upon it.

3.2.3 Paper alignment mechanism –

The paper alignment mechanism is considered as a problem because if not sorted the

papers in a proper manner the prototype shape could be distorted. Thus the Rapid Pro

software has been used as the solution to this problem. The software divides the object into

layers with an alignment mechanism in each layer.

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Methodology

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Laminated Object

Manufacturing

De- cubingOverhanging

Structures

Paper sheet alignment

Selective laser

sintering

3D Printing

Powder

FlourSand Sugar

Types of supports

that could be used

PowderTabs

Flour Powder

The paper alignment

mechanism to avoid distortion

of prototype

Rapid ProSoftware

Frame around the

layer

Holes on upper side of layers

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Chapter four

Implementing the solutionChapter four gives a description on the methods being considered for implementing the

proposed solution

4.1 Eliminating de-cubing and adopting powder as support –

De-cubing being a time consuming, tedious and labour intensive process should be

eliminated and replaced by other supports in the rapid prototyping considering the technology

where the prototype should be made in a rapid manner. De-cubing also causes problems in

the prototype being made and also causes changes in its shape. Thus supports such as wax,

powder should be tried to support the prototype in a faster and efficient manner so as to build

the prototype quickly with the help of supports and also to remove the supports easily without

causing any damage the prototype and also by not causing changes to its shape.

Thus powder is chosen as the solution for supporting the object (prototype) in Laminated

Object Manufacturing. Powder can be easily deposited, can enter deep holes and cavities and

can easily be deposited between the walls of the complex prototypes

Figure 4.1 A complex prototype made by sintering nylon powder [20]

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The prototype in the image above shows how complex it is. It is nearly impossible to make

the prototype with the de-cubing method. The powder can be deposited inside and around the

holes and after the prototype is made and even if the prototype is delicate it can be simply

tilted to remove the powder inside it. The uses of powder as a support in Laminated object

Manufacturing is adopted from other rapid prototyping technologies i.e. 3D printing and

Selective laser sintering. A brief of 3d printing and selective laser sintering is given below –

4.2 Adapting technologies/methods used by other Rapid Prototyping systems –

4.2.1 3D Printing – The system consists of a feed chamber that consists of powder to be

used, the type of the powder varies with the product or the prototype to be made. There is a

build chamber that is adjacent to the feed chamber where the material or the prototype is

built. The position of the build material that is to be built can be changed by the movement of

the feed piston. The powder is deposited on the build platform by a by a roller which is

carried by a horizontally reciprocating carriage. The material is swept down the overflow

chute when it exceeds the level of the material.

Figure 4.2 the process of depositing powder in 3d printing technology [21]

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To match the design of the CAD model, a binder solution is deposited by a binder cartilage

which is also mounted on the carriage. The feed piston then goes down a layer thickness

varying from 0.100 to 0.250 and new layer is deposited as the build platform lowers. The

process is repeated until the final prototype or object is formed.

The roller being used to deposit powder in 3d Printing -

Figure 4.3 a layer of powder being spread by roller [22]

Figure 4.4Binder solution being deposited by the binder cartilage [22]

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Figure 4.5 Roller depositing another layer of powder over the previous one [22]

After the layering is finished the powder that is not used is removed from the build

platform/chamber.

Figure 4.6 the whole process of 3d printing at a glance [23]

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4.2.2 SLS (Selective Laser Sintering)

The selective laser sintering is the process in which a 3D CAD model is used for the

prototype to be made. It is a process in which powder materials are sintered and fused with

help of CO2 laser. Parts are generated by finely ground powders. The SLS machine consists

of the following components –

Build piston

Feed piston

Laser scanner

Levelling roller

Powder cartilage

A bin to collect the excess material

CO2 laser

Figure 4.7 a selective laser sintering machine [24]

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Working of Selective laser sintering – At first the built chamber is heated in order to reduce

the energy so that the laser can sinter the material. The roller spreads a layer on the built

platform and then the laser sinters the material. Once the laser has sintered the material

another layer of powder is deposited/layered over the previous layer. After the completion of

the process i.e. after the prototype is made, the prototype is taken and the excess powder

material is removed.

Figure 4.8 the selective laser sintering process [25]

The SLS being a quick method creates prototypes with good accuracy but has bad surface

finish due to its nature of sintering technology.

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4.3 Powder Selection –

Much type of powders is used in the rapid prototyping technology like 3D Printing, Selective

Laser Sintering etc. But in 3Dprinting and Selective Laser Sintering the powder is used to

make prototype and in case of Laminated Object Manufacturing the powder is only used for

the purpose of supporting, to be replaced with the cubing method. Thus powders that are

easily available can be used considering the firmness it can give to the object while

supporting and also its cost.

3 types of powders could be considered being used for supporting the prototype in Laminated

Object Manufacturing -

Sand

Sugar Particles

Flour

The type of powder was chosen depending on the availability, cost and firmness.

Sand Parti

cles

Flour P

article

s

Suga

r Parti

cles

0123456789

Selection of type of powder

AvailabilityCostFirmnessRemoving the type of powder

Type of Powder

Rati

ng

Graph 4.1 the type of powder was chosen depending on the availability, cost and firmness

Thus Flour has been chosen over sand particles and sugar particles mainly considering its

firmness it offers to the prototype or the object being made and secondly due to its

availability.

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4.4The Selection of method of deposition of powder into chamber – Two approaches were used for the powder deposition mechanism in order to deposit

the powder in proper manner so that it supports the object properly. The first approach is the

use of a scrapper blade to push the powder to the piston bed/build platform where the

prototype is to be made so as to support it.

Figure 4.9 a scraper blade pushing the powder [26]

The problems faced by the scraper blade are –

It requires a significant amount of powder in front of it.

It increases the friction between powder and heap and the underlying layer.

It results in increase in the weight of the material

Figure 4.10 a scraper blade pushing the powder [26]

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The second approach is using a rolling cylinder or a roller. The roller rolls the powder from initial to final position.

Figure 4.11 the roller pushing (rolling) forward powder [26]

The problem faced by the roller is –

The irregularities caused by the roller due to the contact between the powder and the roller

Figure 4.12 the roller pushing the powder [26]

The scraper blade (sharp wiper) has been chose for the deposition purpose as it’s easily

available and even be used manually and easily.

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4.5 Alignment Mechanism of paper sheets –

The alignment of the paper sheets is one of the most important steps to be looked at as

the paper sheets if not aligned properly can lead in distorted shape of prototype. Software

called Rapid Pro is used for the alignment mechanism. The following steps are followed for

the alignment when the Rapid Pro software is used. –

1. Selection of a STL file to be sliced and aligned (In this case a Motorbike have been

chosen)–

2. Selecting the slicing direction (top, left, back, right, bottom and front) of the object or

model to be sliced –

3. Selection of the material to be used, which gives the dimensions of the prototype to be

made –

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Figure 4.13 Slice directions in paper alignment mechanism

Figure 4.14 Object dimension

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4. Calculating the number of slices the model has –

5. The papers are sliced with respect to the layer numbers with holes on the top so as to

align the paper one upon another one so that the prototype has a proper shape with

respect to the CAD model with dimensional accuracy.

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Figure 4.15 slicing of the object

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4.5. Prototypes to be made –

The following 5 prototypes was been selected to be made –

1. Turbine (impellor)

Figure 4.16 Turbine (impellor)

2. Gear (Differential)

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Figure 4.16 paper alignment mechanism

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Figure 4.17 gear (Differential)

3. Snarl (Spherical ball)

Figure 4.18 Snarl

4. Motorbike

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Figure 4.19 motorbike

5. Pen Holder

Figure 4.20 Pen Holder

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4.5.1 Cutting the papers to obtain the paper with correct thickness to get

exact dimensional accuracy of prototype–

Cutting the papers in the laser cutting machine so as to sack it after the parts to be

stacked in each layer is traced out by the laser. Taking different parameters such that when

the thickness is varied there is a change in laser cutting leading to cut the layers depending

upon the set up on the machine. The objective is to cut the paper in a way that even if its

thickness is increased by stacking more papers it cuts through all the layers except the last

layer.

Figure 4.21 the laser cutting machine powder [27]

Figure 4.22 the laser cutter powder [28]

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Objective - To make a turbine (impellor) of 3.4 mm height.

Serial

Number

Change in

parameters and

change in the paper

type and paper

thickness

Observation or variation when changed the

parameters and paper thickness

1. Thickness of

paper - 0.10 mm

A4 size normal

paper

Thickness in

machine – 0.113

mm

Power – 4.4 %

Speed – 80 %

Colour - red

(Used for cutting)

Laser cut this paper but the parts of it started blowing

away due to the air inside the machine. As the density of

paper is very less.

2. Thickness of

paper – 0.20 mm

2 papers of 0.10

mm each stacked

to increase

thickness

Power – 4.4%

Speed – 75 %

Colour – Blue

(Used for scaring)

Two papers were stacked to increase the thickness. As

the cutting of the paper was change to blue thus only

scaring was done and it had no cuts on it. The only

solution for this was to cut by blade or cutter for each

and every layer but as this a time consuming process it

was rejected.

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Figure 9.23 paper thickness of 0.10 being cut to make turbine

Figure 4.24 paper thickness of 0.20 being scored to make turbine

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3. A sticky paper

was used of 0.15

mm thickness

Thickness

adjusted in

machine – 0.113

mm

Power – 12%

Speed – 75%

The Sticky paper is a kind of lalbel were its back side is

eeled of and the sticky surface is sticked to the surface of

machine so that the island parts on it are not blown out

due to its lesser density. The laser cuts the sticky part

and does its job but again there is tiime consuming

process of removing the each island part which is stuck

to the surface of machine due ti its glue effect. After the

part is removed from there it should be properly put in

between the boxed space so thatduring the time of

arranging the layers one upon other proper paper

allignment is followed.

Table 4.1 Selection of paper and proper parameters to make turbine

Result after the cutting of sticky papers –

The turbine –

1. Top view of turbine –

The process of turbine making –

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Figure 4.25 sticky paper of thickness 0.15 mm to make turbine

Figure 4.26 Top view of turbine

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A piston arrangement was made onto a rectangular box container where a plastic pipe was

inserted from its bottom acting as a piston moving up and down. The piston was connected to

a piston bed or build platform which was a thick card board. The process starts with the first

layer being placed on a paper taped on the built platform so that when the layers are stacked

on it stays firm. The layers are stacked and are supported with powder around it and also

supporting the overhanging and island structures. The layering of the powder is done by

wiper mechanism so as to push the power uniformly everywhere.

The wiper being used to push the powder across the built platform.

Figure 4.27 Wiper being used to push powder across build platform

A roller being used to suppress the layers in accordance to reduce the air gap and to

stack the layers properly.

Figure 4.28 roller used for pressing the stacked layers

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The layer being aligned by two holes on its upper part being inserted through a nail so

as to stack the layers above and under it properly in an order so that the final

prototype being made has good accuracy.

Figure 4.28 paper alignment through nails placed on platform

Prototype being ready on the build platform

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Figure 4.29 Prototype being made using sticky papers of 0.15 mm thickness

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2. Side View of the turbine –

3. Bottom view of the turbine

Height – 2.56 cm

Width – 4.5 cm

Thickness of paper used – 0.15 mm

Verdict – The turbine could not be the exact height of 3.14 metre. It had a height of only 2.56

metre and had less accuracy as it was manually built and also as it did not have layers of

proper thickness (the original thickness that had to used was 0.229 mm and the thickness that

was used was 0.15 mm). Thus the difference in thickness in terms of paper resulted in low

height of the turbine (impellor) prototype.

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Figure 4.30 Side view of turbine

Figure 4.31 bottom view of the turbine

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The following experiment was done by paper of different thickness and adjusting various

parameters in the laser cutting machine to cut the paper layers and then form a prototype

of motorbike by stacking the layers.

1. The changes made in the parameters in the laser cutting machine –

Paper thickness – 0.15 mm

Thickness – 0.09mm

Colour- blue

The observation -

In this case the laser cut through the 1st and the 2nd paper

Figure 4.32 paper thickness of 0.15mm thickness being cut by laser

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2. The changes made in the parameters -

The thickness was changed to 0.05 mm

Paper thickness is 0.15 mm

Colour – blue

The Observation -

The laser didn’t cut through the 1st and the 2nd part of the 0.15 mm paper i.e. the; laser

didn’t cut through the paper. Some other observations were –

There was only an outline and a scaring on the paper surface

As the laser didn’t cut through it did not had any paper pieces sticking to the

tack underneath it.

The laser didn’t cut through and this it can be seen that the back side of the

paper is as it is and has no marks of laser on it.

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Figure 4.33 paper thickness of 0.05 adjusted in laser cutting machine being cut by laser

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3. Changes made in parameters in the laser cutting machine –

The Observation –

It took one minute and 25 seconds to cut the paper and the laser cut the paper

throughout with parts of it being stack on the tack due to glue effect. It’s clearly

visible the parts of the paper that got stacked to the tack due to glue effect

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Figure 4.34 Thickness of paper 0.15 mm and 0.08 thickness adjustment made in machine

Machine adjusted thickness - 0.08mm

paper thickness 0.15 mm

Colour - blue

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4. Changes in parameters –

The observation –

The paper was cut through by the laser and was stacked to the tack due to the glue effect

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Figure 4.35 Thickness of paper 0.20 mm and 0.06 thickness adjustment made in machine

Thickness adjusted in machine- 0.06mm

power – 4 %

thickness of paper - 20 mm

Colour - blue

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5. Change in parameters -

The observation - It just had a scar on the first part and leaving no marks on cuts on the second part.

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Figure 4.36 Thickness of paper 0.20 mm and power 20% adjustment made in machine

Thickness of 0.05 mm

Power at 7.4 %

Colour - blue

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6. Change in parameters –

The observation –

Due to the increase in thickness of paper and also as there was tack underneath it, the

laser when started cutting was very adjacent to the paper that it couldn’t cut properly. It only

had scars on 1st and 2nd paper

7.

Change in parameters –

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Figure 4.37 papers being stacked, scoring done by the laser

5 papers stacked together - thickness of paper = 0.55 mm (Increased

thickness

= 0.55mm - 0.15mm = 0.40mm )

The increased thickness includes the 5 papers being stacked and the

glue applied in between them.

Colour - blue

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The

Observation –

The colour of the laser cutting was set strong i.e. red colour and thus the laser cut

through the three layers but the tack underneath didn’t had much power to hold the paper

being stacked to it as the force of air was very high which resulted in blowing of some parts

of layers.

Figure 4.38 thickness of 0.30 mm and power 16% adjusted in laser cutting machine

8. Change in parameters -

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3 papers stacked,

Thickness of paper - 0.30 mm

Thickness being adjusted in machine to cut it - 0.10 mm

Power - 16 %

Colour - red

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The Observation –

The approach was changed as the parts of the paper started blowing due to air

pressure inside the machine, thus the island features in each layers were connected using

bridges with the help of AutoCAD and was then converted to the dxl format for the paper to

be cut. The island objects didn’t blow off and thus this approach is used finally.

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Figure 4.40 thickness of 0.22 mm

Thickness of paper – 0.22 mm

Power - 9%

colour – blue

Thickness adjusted in machine - 0.30 mm

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4.6 Stacking of papers –

The paper sheets should be placed one upon each other in such a way that the holes on

top of layers goes exactly through the smooth and firm nails placed on the built platform of

the machine which will avoid distortion of the prototype. The next paper sheet should be

glued underneath it with a super glue in order to stick it on top of the previous layer such it

fits it perfectly. Once the layer sits perfectly the unwanted parts of the layer (paper sheet) can

be removed. The process is repeated until all layers are being stacked and the prototype is

formed.

4.7 Prototype made –

The paper that is chosen is a thick sheet of width 0.22 mm to make the prototype. The

other 3 prototypes i.e. snarl, gear and the pen holder couldn’t be made due to lack of time.

4.7.1 The turbine (impellor) prototype –

1. Front view

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Figure 4.41 turbine prototype -front view

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2. Back view

3. Top View –

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Figure 4.42 turbine prototype -back view

Figure 4.43 turbine prototype -top view

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4.7.2 The Motorbike prototype – Top view –

Front View –

Figure 4.45 Motorbike prototypes - front view

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Figure 4.44 Motorbike prototypes - top view

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The motorbike made by 3D Printing machine-

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Figure 4.46 prototype made by 3d printing

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4.8 Supporting the island structures –

Two solutions were being found out for supporting the island structures or over hanging structures -

The first approach was - The island or the overhanging structures in the prototype can

be supporting the island or the overhanging structures in the prototype by rolling the

sticky paper and placing it correctly such that the peel off paper which is above the

rolled paper is stick to lower part of layer (island) to be stacked and the sticky paper

roll is stick to the platform. The paper can be rolled depending upon the height of the

island structure form the built platform. After the island structure is connected to the

prototype by the stacking process, the support structure can be removed using forceps

or small pickups even if the island is in a complex place.

The second approach was using the powder itself for supporting the prototype and

also to give supports to the island structure as it can be easily deposited and removed.

The powder has been chosen to support the island structures as it is been already considered

as the support material replacing the de-cubing method. The powder can be removed from

any complex places in the prototype as compared to the sticky paper roll. Thus adopting

powder for even supporting the island objects is regarded as the better solution.

Chapter 5

Results and Discussion5.1 The prototypes made -

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5.1.1 The turbine prototype

Figure 10.1 Turbine prototype made by LOM without de-cubing

5.1.2 The Motorbike prototype

Figure 5.2 Motorbike prototype made by LOM without de-cubing

5.2 Dimensional comparison of the CAD model of turbine and the prototype:-

Dimensional

Parameter

Original Object Prototype Difference

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Inducer

Diameter

(millimetre)

54 50 54-48 = 4

Exducer

Diameter

(millimetre)

33 28 33-28 = 0.5

Shaft hole

Diameter

(millimetre)

1 1 0

Shaft Hole

Depth

(millimetre)

54 48 54-48 = 6

Overall Length

of the Turbine

(millimetre)

54 48 54-48 = 6

Table 5.1 dimensional comparison of Turbine CAD model and turbine made by LOM

5.2.1 Graphical Representation of quality of manually made turbine prototype and the turbine of proper dimensions –

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Figure 5.3 turbine CAD model

Figure 5.4 turbine prototype made by LOM

without de-cubing

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Inducer Diameter

Exducer Diamter

Shaft Hole

Diamter

Shaft hole

depth

Exducer Diamter

0

1

2

3

4

5

6

Dimensional Comparison(Quality)

Turbine made by LOMTurbine Model

Dimensional Parametrs

Mill

imet

er

Graph 5.1 dimensional comparisons of Turbine CAD model and turbine made by LOM

Reason for the difference in dimensional parameters –

Improper alignment

Shaking built platform leading to misplacing of some layers

Stacking not being done properly (small gaps in between some layers)

5.3 Supporting the island structure –

The island structures in the complex prototype is to be supported with powder as it

can be easily deposited in the complex places like holes, in between walls etc. and it can also

be removed by just tilting the prototype which will drew away the powder that was deposited

in it.

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5.4 Comparison of dimensional accuracy of motorbike made in 3D printing machine and Motorbike made by Laminated Object Manufacturing (L.O.M) –

Dimensional

Parameters

Motorbike made in 3D

printing machine

Motorbike made by

(L.O.M)

Differenc

e

Diameter of

Front tyre

(Millimetre)

66.85 56.94 9.91

Diameter of

Rear tyre

(Millimetre)

52.64 45.10 7.54

Thickness of

front tyre

(Millimetre)

12 10 2

Thickness of

back tyre

(Millimetre)

12 10 2

Overall

length of bike

(Millimetre)

150 146 4

Overall

height of bike

(Millimetre)

62 59 3

Length of

handle

(Millimetre)

51 48 3

Table 5.2 dimensional comparison of motorbike made by 3d printing and LOM

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5.4.1 Variations in dimensions of motorbike made by 3d printing and motorbike by L.O.M

Diamete

r of f

ront t

yre

Diamete

r of b

ack ty

re

Thicknes

s of f

ront t

yre

Thicknes

s of b

ack ty

re

Overall

length

of b

ike

Overall

heig

ht of b

ike

Length

of h

andle

0

20

40

60

80

100

120

140

160

Dimensional Comparison (Quality)

Motorbike made by 3d printingMotorbike made by LOM

Dimensional Pramaters

Mill

imet

er

Graph 5.2 dimensional comparison of motorbike made by 3d printing and LOM

The reasons for variations in dimensions are because –

Improper alignment mechanism of paper sheets

Improper paper sheet stacking leading to space between some layers

Manual process leading to movement in prototype when not placing the layers

properly

Bad surface finish

The nails on the built platform were not properly arranged

The built platform wasn’t with correct dimensions with respect to the chamber

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5.4.2 The Time comparison in case of Motorbike built by 3d printing and LOM

The total time took by 3d printing in building motorbike is 17 hours and 43 minutes

i.e. 1063 minutes and the time taken for building the motorbike in Laminated Object

Manufacturing is 13 hours and 35.minutes i.e. 815 minutes. Thus there is a time difference of

248 minutes i.e. 4 hours and 13 minutes. Therefore using Laminated Object Manufacturing

over 3D Printing saves 248 minutes.

0

200

400

600

800

1000

1200

Time Comparison

Mototrbike made by 3d printingMotorbike made by L.O.M

Time taken

Min

utes

Graph 5.3 Comparison of time taken for motorbike made by 3d printing and LOM

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5.4.3 Cost Comparison in case of Motorbike built by 3d printing and Laminated Object Manufacturing (L.O.M)-

The material cost for building motorbike by 3D Printing–

Material required to make motorbike = 180 cm3

The cost of 997 cm3is 270 pounds,

Therefore cost for 180 cm3 = 270997

* 180 = 48.74 pounds

The material cost for building motorbike by L.O.M –

Energy cost = 0.167 pounds (in one hour the machine consumes 0.835 kilo watt, thus

as one unit costs 10 pence; the energy cost = 0.835 * 0.10 * 2 = 0 167 pounds)

Material cost = 10.60 pounds

Total cost made to build the motorbike = 10.60+0.167 = 10.76 pounds.

Thus the price difference between the motorbike made by 3D Printing when compared with

that of L.O.M = (48.74 - 10.76) pounds = 37.98 pounds

Cost0

5

10

15

20

25

30

35

40

45

50

Cost Comparison

Motorbike built by 3d print-ing Motorbike built by L.O.M

Pou

nds

Graph 5.4 Cost comparison of motorbike made by 3d printing and LOM

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5.5 A comparison of manually made prototype with the prototype made by 3d printing –

Quality Cost Time0

1

2

3

4

5

6

7

8

Prototype made by Laminted Ob-ject Manufacturing

Prototype made by other rapid protyping systems(3D Printing)

Graph 5.5 Quality, Cost and Time comparison of Prototype made by 3D Printing and L.O.M

The graph depicts that the prototype made by Laminated Object Manufacturing lacks

a bit quality when compared with prototype made by 3D printing due to its poor surface

finish which could be improved in future. The cost shows that prototype made by Laminated

Object Manufacturing is much cost effective when compared to that made by 3D printing and

the prototype made by Laminated Object Manufacturing is also time efficient when compared

with that of 3D printing.

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Chapter 6

Conclusion and Future work –

Conclusion –

The Laminated Object Manufacturing (L.O.M) can be regarded as one of the quick rapid

prototyping systems where powder has been adopted as the new support for supporting the

complex prototypes with the elimination of the de-cubing method. The prototype has been

made in this process by eco-friendly and recyclable materials which are easily available and

are cheaper ingredients as raw materials. It has been proved that any complex prototype

could be made by L.O. M. in a cost effective way and also has proved to be time efficient.

The only problem seen in this method was a poor surface finish which could be easily sorted

out by proper alignment mechanism and providing improvements in some aspects of the

machine where the built platform has proper dimensions with respect to the built chamber.

Future Work –

The future work aims at advancement of this system by making it completely

automated in order to save time and improve the surface finish The following changes shall

be made considering the automation of the machine -

Automatic powder deposition with the scraper blade resulting in uniform deposition

of powder across the platform.

To automate the stacking process so as to avoid paper sheet alignment method

problems when done manually so as to provide accurate paper alignment method.

To make the machine more cost effective and time efficient

Steps undertaken to increase the quality of the product, specially the surface finish.

Papers which are used for stacking and making the prototype should be adhesive

papers such that they are sticky enough to automatically getting stuck to the previous

layer so that manual applying of adhesives is neglected

A pipe with cork into a container for collecting the powder shall be provided such that

it is connected to a small hole and cork under the chamber in order to properly remove

the powder in the process so as to re-use the powder for the deposition process.

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Reference

References for images –

1. Chuva C.K., L. K. L. C., 2003. Rapid Prototyping Princples and applications. Second

ed. Singapore: World Scientific Publishing Co. Pte. Ltd.

2. Pandey, P. M., n.d. Rapid Prototyping technologies,applications and part deposition

planing. [Online]

Available at: http://web.iitd.ac.in/~pmpandey/MEL120_html/RP_document.pdf

[Accessed 15 3 2012].

3. Steve Upcraft, R. F., 2003. The Rapid Protoryping technologies. Assembly

Automation, 3 11.23(ISSN 0144-5154).

4. Baytek Software Dev. Co.. [Online]

Available at: http://www.baygan.com/Experience/Stereolithography.aspx

[Accessed 2012 2 2012].

5. Centre for Bio Molecular Modeling. [Online]

Available at: http://www.rpc.msoe.edu/cbm/about/sla.php

[Accessed 2012 2 2012].

6. Direct Industry. [Online]

Available at: http://www.directindustry.com/prod/eos/laser-plastic-sintering-

machines-5078-293405.html

[Accessed 19 2 2012].

7. jj204teknologiworkshop2. [Online]

Available at: http://jj204teknologiworkshop2.blogspot.co.uk/p/rapid-prototyping.html

[Accessed 19 2 2012].

8. Multistation. [Online]

Available at: http://www.multistation.com/en/spip.php?page=impression-

article&id_article=445

[Accessed 20 2 2012].

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9. Anon., n.d. Major RP Technologies. [Online]

Available at: http://www.uni.edu/~rao/rt/major_tech.htm#LOM

[Accessed 20 2 2012].

10. PC STATS. [Online]

Available at: http://www.pcstats.com/releaseview.cfm?releaseID=1688

[Accessed 21 2 2012].

11. An Introduction to Rapid Prototyping. [Online]

Available at: http://www.ielm.ust.hk/dfaculty/ajay/courses/ieem513/RP/RPlec.html

[Accessed 21 2 2012].

12. Alchemy models inc.. [Online]

Available at: http://www.alchemymodels.com/KC-AM.html

[Accessed 22 2 2012].

13. xpress 3d. [Online]

Available at: http://www.xpress3d.com/Processes.aspx

[Accessed 22 2 2012].

14. xpress 3d. [Online]

Available at: http://www.xpress3d.com/Materials.aspx

[Accessed 22 2 2012].


Available at: http://pdf.directindustry.com/pdf/universal-laser-systems/pls-platform-

series/Show/14769-217687.html

[Accessed 10 4 2012].

16. Purex fume extraction system. [Online]

Available at: http://www.purex.co.uk/fume-extraction/

[Accessed 10 4 2012].

17. Inhaeng Choa, K. L. W. C. Y.-A. S., 2000. Development of a new sheet deposition

type rapid prototyping system. International Journal of Machine Tools and

Manufacture, 40(12), p. 3.

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18. RPWORLD.NET. [Online]

Available at: http://rpworld.net/cms/index.php/additive-manufacturing/rp-rapid-

prototyping/sla-stereo-lithography-apparatus.html

[Accessed 24 2 2012].

19. Fwu-Hsing Liu, Y.-S. L., 2010. Fabrication of inner complex ceramic parts by

selective laser gelling. Journal of the European Ceramic Society, 30(16), p. 5.

20. Yatzer. [Online]

Available at: http://www.yatzer.com/Lexus-on-the-Milan-design-week

[Accessed 12 4 2012].

21. S.-J.J. Lee, E. S. M. C., 1995. Layer position accuracy in powder-based rapid

prototyping. Rapid Prototyping Journal, 1(4), pp. 27-34.

22. z corporation. [Online]

Available at: http://itg.beckman.illinois.edu/visualization_laboratory/equipment/

3Dprinting/files/791_8914-3DPrintingWhitePaper.pdf

[Accessed 18 4 2012].

23. An Introduction to Rapid Prototyping. [Online]


[Accessed 21 2 2012].

24. lasersintering.com. [Online]

Available at: http://www.lasersintering.com/sls-information.php

[Accessed 20 2 2012].

25. Custompart.net. [Online]

Available at: http://www.custompartnet.com/wu/selective-laser-sintering

[Accessed 19 2 2012].

26. B. Van der Schueren, J. K., 1995. Powder deposition in selective metal. Rapid

Prototyping Journal, 1(3), pp. 21-31.


Available at: http://pdf.directindustry.com/pdf/universal-laser-systems/pls-platform-

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series/Show/14769-217687.html

[Accessed 10 4 2012].

28. Universal laser systems. [Online]

Available at: http://www.ulsinc.com/.

[Accessed 12 4 2012].

Other References -

2011. Castle Island's worldwide guide to rapid protoyping. [Online]

Available at: http://www.additive3d.com/rp_int.htm

[Accessed 8 3 2012].

Alchemy models inc.. [Online]

Available at: http://www.alchemymodels.com/KC-AM.html

[Accessed 22 2 2012].

An Introduction to Rapid Prototyping. [Online]


[Accessed 21 2 2012].

Arptech Rapid Prototyping services. [Online]

Available at: http://www.arptech.com.au/slshelp.htm

[Accessed 25 2 2012].

Baytek Software Dev. Co.. [Online]

Available at: http://www.baygan.com/Experience/Stereolithography.aspx

[Accessed 2012 2 2012].

Centre for Bio Molecular Modeling. [Online]

Available at: http://www.rpc.msoe.edu/cbm/about/sla.php

[Accessed 2012 2 2012].

Anon., n.d. Custompart.net. [Online]

Available at: http://www.custompartnet.com/wu/selective-laser-sintering

[Accessed 19 2 2012].

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Direct Industry. [Online]

Available at: http://www.directindustry.com/prod/eos/laser-plastic-sintering-machines-5078-

293405.html

[Accessed 19 2 2012].

Direct Industry. [Online]

Available at: http://pdf.directindustry.com/pdf/universal-laser-systems/pls-platform-series/

Show/14769-217687.html

[Accessed 10 4 2012].

explainingthefuture.com. [Online]

Available at: http://www.explainingthefuture.com/3dprinting.html

[Accessed 21 2 2012].

Anon., n.d. jj204teknologiworkshop2. [Online]

Available at: http://jj204teknologiworkshop2.blogspot.co.uk/p/rapid-prototyping.html

[Accessed 19 2 2012].

lasersintering.com. [Online]

Available at: http://www.lasersintering.com/sls-information.php

[Accessed 20 2 2012].

Major RP Technologies. [Online]

Available at: http://www.uni.edu/~rao/rt/major_tech.htm#LOM

[Accessed 20 2 2012].

Multistation. [Online]

Available at: http://www.multistation.com/en/spip.php?page=impression-

article&id_article=445

[Accessed 20 2 2012].

PC STATS. [Online]

Available at: http://www.pcstats.com/releaseview.cfm?releaseID=1688

[Accessed 21 2 2012].

Protosys technologies Pvt. ltd.. [Online]

Available at: http://www.protosystech.com/rapid-prototyping.htm

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[Accessed 19 2 3012].

Purex fume extraction system. [Online]

Available at: http://www.purex.co.uk/fume-extraction/

[Accessed 10 4 2012].

Purex Fume Extraction systems. [Online]

Available at: http://www.purex.co.uk/shop/Systems/Digital-Systems/1500i/p-74-75-138/

[Accessed 10 2 2012].

RPWORLD.NET. [Online]

Available at: http://rpworld.net/cms/index.php/additive-manufacturing/rp-rapid-prototyping/

sla-stereo-lithography-apparatus.html

[Accessed 24 2 2012].

Universal laser systems. [Online]

Available at: http://www.ulsinc.com/.

[Accessed 12 4 2012].

Anon., n.d. xpress 3d. [Online]

Available at: http://www.xpress3d.com/Processes.aspx

[Accessed 22 2 2012].

xpress 3d. [Online]

Available at: http://www.xpress3d.com/Materials.aspx

[Accessed 22 2 2012].

xpress 3d. [Online]

Available at: http://www.xpress3d.com/SLS.aspx

[Accessed 26 2 2012].

Yatzer. [Online]

Available at: http://www.yatzer.com/Lexus-on-the-Milan-design-week

[Accessed 12 4 2012].

z corporation. [Online]

Available at: http://itg.beckman.illinois.edu/visualization_laboratory/equipment/3Dprinting/

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files/791_8914-3DPrintingWhitePaper.pdf

[Accessed 18 4 2012].

B. Van der Schueren, J. K., 1995. Powder deposition in selective metal. Rapid Prototyping

Journal, 1(3), pp. 21-31.

Chuva C.K., L. K. L. C., 2003. Rapid Prototyping Princples and applications. Second ed.

Singapore: World Scientific Publishing Co. Pte. Ltd..

Fwu-Hsing Liu, Y.-S. L., 2010. Fabrication of inner complex ceramic parts by selective laser

gelling. Journal of the European Ceramic Society, 30(16), p. 5.

Inhaeng Choa, K. L. W. C. Y.-A. S., 2000. Development of a new sheet deposition type rapid

prototyping system. International Journal of Machine Tools and Manufacture, 40(12), p. 3.

Pandey, P. M., n.d. Rapid Prototyping technologies,applications and part deposition planing.

[Online]

Available at: http://web.iitd.ac.in/~pmpandey/MEL120_html/RP_document.pdf

[Accessed 15 3 2012].

S.-J.J. Lee, E. S. M. C., 1995. Layer position accuracy in powder-based rapid prototyping.

Rapid Prototyping Journal, 1(4), pp. 27-34.

Steve Upcraft, R. F., 2003. The Rapid Protoryping technologies. Assembly Automation, 3

11.23(ISSN 0144-5154).

Y. S. LIAO, Y. Y. C., 2001. Adaptive crosshatch approach for the laminated object

manufacturing. International Journal of Production Research, 39(15), pp. 3479-3490.

Y.S. Liao, L. C. Y. C., 2003. A new approach of online waste removal process for. Journal of

Materials Processing Technology, 140(1-3), pp. 136-140.

Appendix

The following table is the process of selecting a proper paper thickness for making turbine –

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Serial number

Change in Parameters and thickness of papers that are stacked

Observation or variation when changed the parameters and paper thickness

1. The thickness was changed to 0.09 mm.

Paper thickness – 0.15 mm

Colour - blue

The observation of this parameter being chosen was that the laser cut through the whole 1st and 2nd part.

2. The thickness was changed to 0.05 mm

Paper thickness is 0.15 mm

Colour - blue

The Observation was that it didn’t cut through the 1st and 2nd part of the 0.15 mm i.e. the laser didn’t cut throughout the paper.

i. There was only an outline and a scaring on the paper surface.

ii. As the laser didn’t cut through it did not had any paper pieces sticking to the tack underneath it.

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iii. The laser didn’t cut through and this it can be seen that the back side of the paper is as it is and has no marks of laser on it.

3. Machine adjusted thickness - 0.08mm

paper thickness 0.15 mm

Colour - blue

It took one minute and 25 seconds to cut the paper and the laser cut the paper throughout with parts of it being stack on the tack due to glue effect.

It’s clearly visible the parts of the paper that got

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stacked to the tack due to glue effect

4. Thickness adjusted in machine- 0.06mm

power – 4 % thickness of

paper - 20 mm Colour - blue

The paper was cut through by the laser and was stacked to the tack due to the glue effect.

5. Thickness adjusted at 0.03 mm

No difference was found from the previous one as it again cut through the paper and stacked to the tack.

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power at 4.4 % 75% speed

6. Thickness of 0.05 mm

power at 7.4 % Colour - blue

It just had a scar on the first part and leaving no marks on cuts on the second part.

7. 5 papers stacked together - thickness of

Due to the increase in thickness of paper and also as there was tack underneath it, the laser when started cutting was very adjacent to the paper that it couldn’t cut

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paper = 0.55 mm (Increased thickness = 0.55mm - 0.15mm = 0.40mm )

The increased thickness includes the 5 papers being stacked and the glue applied in between them.

Colour - blue

properly. It only had scars on 1st and 2nd paper.

8. 3 paper being stacked together with thickness of 30 mm, thickness adjusted in the settings – 20 mm

Power - 4.4% Colour - blue

It didn’t cut through the 3rd paper but the laser cut through the 1st and 2nd paper.

9. 3 papers stacked Thickness =

0.30 mm

3 papers were stacked together and blue-tack was placed underneath it the laser didn’t cut through any of the layers but had scars on the 1st paper.

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Thickness adjusted = 20mm

Power – 4.4% Blue-tack

underneath it Colour - blue

10. 3 papers stacked, Thickness of paper

- 0.30 mm Thickness being

adjusted in machine to cut it - 0.10 mm

Power - 16 % Colour - red

The colour of the laser cutting was set strong i.e. red colour and thus the laser cut through the three layers but the tack underneath didn’t had much power to hold the paper being stacked to it as the force of air was very high which resulted in blowing of some parts of layers.

11. 3 papers stacked, Thickness of

paper - 0.30 mm

The laser cut through 1st and 2nd paper and had scars on the 3rd paper. The results was repeated 5 times to make sure the parameters are correct and the layers can be cut

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Power - 25 % with this parameter but after 2 times there was change were only the first layer was cut.

12. Thickness of paper – 0.22 mm

Power - 9%colour – blue

Thickness adjusted in machine - 0.30 mm

The approach was changed as the parts of the paper started blowing due to air pressure, thus the island features in each layers were connected using bridges with the help of AutoCAD and was then converted to the dxl format for the paper to be cut. The island objects didn’t blow off and thus this approach is used finally.

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Developing a Process for Laminated Object Manufacturing (Rapid Prototyping) Without de-cubing.

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