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SURFACE PREPARATION AND ADHESIVE JOINING
Mohamad Asrul Bin Mustapha
Bachelor of Engineering with Honours
TP (Mechanical Engineering and Manufacturing System)
968 2005
[4697 2005
R13a BORANG PENGESAHAN STATUS TESIS
Judul: SURFACE PREPARATION AND ADHESIVE JOINING
SESI PENGAJIAN: 2004 / 2005
Saya MOHAMAD ASRUL BIN MUSTAPHA
(HURUF BESAR)
mengaku membenarkan tesis * ini disimpan di Pusat Khidmat Maklumat Akademik, Universiti Malaysia Sarawak dengan syarat-syarat kegunaan seperti berikut:
I. Tesis adalah hakmilik Universiti Malaysia Sarawak.
2. Pusat Khidmat Maklumat Akademik, Universiti Malaysia Sarawak dibenarkan membuat salinan untuk tujuan pengajian sahaja.
3. Membuat pendigitan untuk membangunkan Pangkalan Data Kandungan Tempatan.
4. Pusat Khidmat Maklumat Akademik, Universiti Malaysia Sarawak dibenarkan membuat salinan tesis i. ni sebagai bahan pertukaran antara institusi pengajian tinggi.
5. ** Sila tandakan ( 10 ) di kotak yang berkenaan
F-1 SULIT (Mengandungi maklumat yang berdaryah keselamatan atau kepentingan
Malaysia seperti yang termaktub di dalam AKTA RAHSIA RASMI 1972). TERHAD (Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/
badan di mana penyelidikan dijalankan).
0
TIDAK TERHADDisahkan oleh
(TANDATANGAN PENULIS)
Alamat tetap: No. 109, Lotung 6C,
Taman Mci Lee, Jln Stakan, Kota Sentosa, 93250,
Kuching, Sarawak.
(TA AN PE YELIA)
Prof. Madya Dr. Sinin Bin Hamdan
Nama Penyelia
Tarikh: 14th March 2005 Tarikh: 14d' March 2005
CATATAN "
"a
Tesis dimaksudkan sebagai tesis bagi Ijazah Doktor Falsafah, Sarjana dan Sarjana Muda.
Jika tesis ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasi herkenaan dengan menyatakan sekali sebab dan tempoh tesis ini perlu dikelaskan sebagai
APPROVAL SHEET
This project report, which entitled "Surface Preparation and Adhesive Joining" was prepared by Mohamad Asrul Bin Mustapha as a partial fullfilment for the Bachelor's
Degree of Engineering with Honours (Mechanical Engineering and Manufacturing Systems) is hereby read and approved by:
Prate'Ma-dya Dr. Sinin Bin Hamdan
Date : ljo
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LAYIVERSITI MALAYSIA SARAwAK 943(KI Kaa Smarslm
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SURFACE PREPARATION AND ADHESIVE JOINING
MOHAMAD ASRUL BIN MUSTAPHA
This project is submitted in partial fulfilment of
the requirements for the degree of Bachelor of Engineering with Honours (Mechanical and Manufacturing Systems)
Faculty of Engineering
UNIVERSITI MALAYSIA SARAWAK
2005
Dedicated to my beloved family and love one
ACKNOWLEDGEMENT
The author wishes to convey his deepest thanks and gratitude to Associate
Professor Dr. Sinin Hamdan for his supervision, expert advice and tremendous
assistance in conducting this thesis. The author thank his for the times spend in
helping to expand and correct the ideas about the thesis, enable the author to learn a
lot of new things and enhance his skills in analyzing data. Without his immeasurable
guidance, skill and patience, the author would not be able to enhance and improve
the contents of thesis to as it now.
With this opportunity, the authors would like to gratefully acknowledge
CRAUN Research
Sdn. Bhd for their contributions and initiating this project.
The author would also like to thanks the staff of the faculty of Engineering, Universiti Malaysia Sarawak and friends who have help the author in the process of conducting and computing the thesis.
Finally, the author would like to express his gratitude to his loving family for their endless support and encouragement in finishing this thesis.
ABSTRACT
This project investigates the surface preparation effect on the strength of the adhesive joint. Strength of new invented adhesive namely sago glue also be compared with other wood adhesive available in market. In this research, abrading with sand paper is used as the surface preparation. 3 types of grit; grit 60(coarse), grit
120(fine), grit 180(super fine) choose to differ the surface roughness effect. The specimen materials are Behan wood (Eusideroxylon Zwageri) and Meraka Wood (Shorea Albida). The other adhesive used in this project are: High Solid Polyvinyl adhesive, White Wood Glue, and Kangaroo Glue.
Result shows that the surface preparation is always needed in bonding
procedure. Abrading with sandpaper drastically increase the bonding strength.
Results revealed that each adhesive has a different surface preparation or different
degree of roughness needed to achieve the maximum bonding strength.
Analysis of stress - strain graph shows that the wood adhesives available in the market are brittle kind of characteristic. Load to failure graph shows that the sago glue can still be accepted as the wood adhesive event though it cannot resist load more than 1700 N average. Kangaroo glue cannot be accepted as a wood adhesive because of the tensile load to failure is very low.
ABSTRAK
Projek ini mengkaji tentang kesan penyediaan permukaan terhadap kekuatan sambungan bahan lekatan. Kekuatan gam yang barn dicipta yang dikenali sebagai gam sagu dibandingkan dengan gam kayu yang lain yang terdapat di pasaran. Dalam kajian ini, penggosokkan kertas pasir dilakukan sebagai penyediaan permukaan kayu. 3 jenis grit kertas pasir iaitu grit 60(kasar), grit 120(sederhana), grit 180(halus) dipilih untuk membandingkan kesan pengasaran permukaan. Spesimen yang digunakan adalah daripada Kayu Behan (Eusideroxylon Zwageri) dan Kayu Merakak (Shorea Albida). Gam - gam lain yang digunakan dalam kajian ini adalah: High Solid Polyvinyl Adhesive, White Wood Glue, dan Kangaroo Glue.
Data menunjukkan penyediaan permukaan seharusnya dilakukan dalam proses pelekatan. Penggosokkan menggunakan kertas pasir menunjukkan peningkatan yang drastik terhadap kekuatan sambungan. Data juga menunjukkan setiap gam mempunyai tahap kekasaran yang tertentu bagi mencapai kekuatan sambungan yang maksimum.
Analisis terhadap graf stress - strain menunjukkan gam yang terdapat di pasaran mempunyai sifat rapuh. Graf had beban menunjukkan gam sago masih boleh diterima sebagai gam kayu walaupun tidak dapat menampung beban lebih daripada
1700 N purata. Gam kangaroo tidak dapat dispesifikasikan sebagai gam kayu disebabkan ketahanan bebanan yang boleh ditampung adalah sangat kecil.
Pusat Khidmat Maldumat Atadetnik
VERSITZ MALAYSIA SARAWAB
94" Kots Santa
TABLE OF CONTENT
THESIS TITLE DEDICATION ACKNOWLEDGEMENT ABSTRACT ABSTRAK TABLE OF CONTENTS LIST OF FIGURES LIST OF TABLES NOMENCLATURE CHAPTER 1INTRODUCTION
1.1 Introduction1.2 The selection of substance 1.3 The Surface Preparation
1.4 Scope and Objective
CHAPTER 2
LITERATURE REVIEW 2.1 Introduction
2.2 Type of Stress
2.3 Variation in adhesive Bonding 2.3.1 Single Lap Joint
2.4 Surface Preparation
1 11 lll IV V vi ix X11 xiv I2
2 45
6
8
10
11
Vi2.5 Adhesion to Wood 2.5.1 Wettability 2.6 Sago CHAPTER 3 METHODOLOGY 3.1 Introduction
13
16
17
19
3.2 Process Sequence 203.2.1 Part I: Substrate Construction 21
3.2.2 Part II: Surface Preparation 23
3.2.3 Part III: Gluing Procedure 24
3.2.4 Testing Method 26
CHAPTER 4
RESULT AND DISCUSSION
4.1 Introduction 28
4.2 Different Type of Surface Preparation Analysis 28
4.2.1 Belian Wood 29
4.2.2 Meraka Wood 37
4.3 Glue Tensile Strength Comparison 45
4.3.1 Belian Wood 45
4.3.2 Meraka Wood 47
4.4 Discussion 49
CHAPTER 5
CONCLUSION AND RECOMMENDATION 5.1 Conclusion 5.2 Recommendation
57
58
Reference
59
Appendix
63
viiLIST OF FIGURES
CHAPTER 2
Figure 2.2 Figure 2.3a Figure 2.3b Figure 2.5.1 CHAPTER 3 Figure 3.2.1 c Figure 3.2.1 d Figure 3.2.1 e Figure 3.2.2 Figure 3.2.4a Figure 3.2.4b CHAPTER 4 Figure 4.2.1 a Figure 4.2.1 b Figure 4.2.1 cLITERATURE REVIEW
Types of stress to which an adhesive joint may be subjected.
Some common engineering adhesive joint.
Peel stress vs distance X along overlap with a gap and no gap.
Contact angle (0) of a sessile drop on a solid
surface, and the resultant surface tensions.
METHODOLOGY
Received Samples Before Modification.
Samples After Modification with Dimensions. Samples Glued Together.
Abrading process.
Form and Dimension of Test Specimen. Specimen in Testometric.
RESULT AND DISCUSSION
Surface preparation comparison graph for Sagu SS-PA- 12012005.
Surface preparation comparison graph for Sagu SS-PA-14012005.
Surface preparation comparation Graph for High Solid Polyvinyl Adhasive.
6
8
9
16
22 22 22 24 27 2734
34
35
ixFigure 4.2.1 d Surface preparation comparison graph for 35 White Wood Glue.
Figure 4.2.1 e Surface preparation comparison graph for 36 Kangaroo Glue.
Figure 4.2.2a Surface preparation comparison graph for Sagu 42 SS-PA- 12012005.
Figure 4.2.2b Surface preparation comparison graph for Sagu 42 SS-PA-14012005.
Figure 4.2.2c Surface preparation comparation Graph for 43 High Solid Polyvinyl Adhasive.
Figure 4.2.2d Surface preparation comparison graph for 43 White Wood Glue.
Figure 4.2.1 e Surface preparation comparison graph for 44 Kangaroo Glue.
Figure 4.3.1 a
Adhesive comparison graph for grit 60. (Belian
45
Wood).
Figure 4.3.1 b Adhesive comparison graph for grit 120.45 (Belian Wood).
Figure 4.3.1 c Adhesive comparison graph for grit 180.46 (Belian Wood).
Figure 4.3.2a Adhesive comparison graph for grit 60.47 (Meraka Wood).
Figure 4.3.2b Adhesive comparison graph for grit 120.47 (Meraka Wood).
Figure 4.3.2c Adhesive comparison graph for grit 180.48 (Meraka Wood).
Figure 4.4a Relationship between adhesion and wettability 50 of yellow poplar and southern pine samples
bonded with PVA adhesive.
Figure 4.4b Interfacial shear strength between wood veneer 52 and polypropylene in wood veneer pull out test.
Figure 4.4c
Peak and valley at wood surface.
52
Figure 4.4d
Difference from mean values of Litshitz van der
53
Waals component of surface free energy as a
function of grain size (spruce and beech).
Figure 4.4e High Solid Polyvinyl Adhesive Stress - Strain 55 graph.
Figure 4.4f Kangaroo Glue Stress - Strain graph. 56
LIST OF TABLE
CHAPTER 2
LITERATURE REVIEW
Table 2.3.1 Different type of design for single lap joint 10
CHAPTER 3 METHODOLOGY
Table 3.2.1 a Belian wood mechanical properties 21 Table 3.2.1 b Meraka wood mechanical properties 21
Table 3.2.2 Sandpapers characteristic 23
Table 3.2.3 Adhesive curing time 25
CHAPTER 4 RESULT AND DISCUSSION
Table 4.2.1a
Data for Sagu SS-PA-12012005
bonding failure
29
load with different surface preparation.
Table 4.2.1b Data for Sagu SS-PA-14012005 bonding failure 30 load with different surface preparation.
Table 4.2.1 c Data for White Wood Glue bonding failure load 31 with different surface preparation.
Table 4.2.1 d
Data for High Solid Polyvinyl Adhesive
32
bonding failure load with different surface
preparation.
Table 4.2.1 e Data for Kangaroo Adhesive bonding failure 33 load with different surface preparation.
Table 4.2.2a
Data for Sagu SS-PA-12012005
bonding failure
37
load with different surface preparation.
Table 4.2.2b Data for Sagu SS-PA-14012005 bonding failure 38 load with different surface preparation.
Table 4.2.2c Data for White Wood Glue bonding failure load 39 with different surface preparation.
Table 4.2.2d
Data for High Solid Polyvinyl Adhesive
40
bonding failure load with different surface
preparation.
Table 4.2.2e Data for Kangaroo Adhesive bonding failure 41 load with different surface preparation.
NOMENCLATURE
F Applied force in Newton
A
et
L
cross-sectional
area of the adhesive bonding in mm2
change in displacement in mm
original length in mm
CHAPTER 1
INTRODUCTION
1.1 Introduction
The strength of a joint strongly depends on the condition and environment of the surface bonding. The purpose of the surface preparation is to produce clean bonding surface and improve its strength. Improper preparation will result in an interfacial failure in the joining.
The adhesive joining is preferred rather than the mechanical fastener due to its higher stiffness, more uniform load distribution, and more over no holes drilled in adherents. The study of adhesive is also important to determine the right adhesive for a substance. Combination of good surface preparation and adhesive may produce high strength of joining. This study will be beneficial for engineering industry especially for aerospace application by manipulating one of adhesive joining advantages, that is eliminating the usage of drilling holes for nuts and bolts thus improve the aerodynamic design.
Although in many applications no form of pretreatment is employed for the substrate materials prior to adhesive bonding, to attain the maximum joint performance some form of surface pretreatment for the substrate materials being joined is almost always necessary [1].
1.2 The selection of substance
The selection of substance depends on application been used in engineering industry. For the study, wood been chosen. Wood had been used in engineering industry since long time ago until metal took place, due to the strength higher than wood. Although metal replace wood, the used of wood still on demand especially in furniture and aerospace industry.
When kept under dry conditions, wood and wood bonds are very durable, but some wood is normally subjected to significant environmental changes that greatly reduce the integrity of the bonded assembly [2].
Based on the demand and the properties of wood, the selection of wood as a
substance
in this study is valuable.
1.3 The surface preparation
Bonding strength develop through joint design are useless if the surface to be bonded is not prepare carefully for its requirement. The types of surface preparation depends on the required bonded strength, as discuss by R. D Adams et al [3], surface treatment of an adherend prior to adhesive bonding can bring about one or a combination of the following effects:
1. remove material
2. modify the chemistry of the surface 3. change the surface topography
Since the substance may be wood, the surface preparations that can be done is
abrasion treatment.
Abrasion Treatment
This method removing the surface of the material or specifically to remove the weak boundary area of the surface materials. Abrasive papers, grit and shot blasting are kind of equipments use in abrasive methods. This kind of treatments can remove up to 10 of µm from the surface.
Solvent Cleaning
Solvents are in liquids or in vapor degreasing. Its act very effectively in removing oils and greases especially from metals. Safety precaution must be taken seriously due to its toxicity behavior.
Chemical Etching
Chemical etching is one of the widely used procedures. It had been used because of its superior durability in wet conditions. Solutions that usually had been used are chromic, chromic and sulfuric, or phosphoric acids. Chemical etching normally used for metal surface preparation like aluminium.
1.4 Scope and Objective
The main objectives of this project are as stated below:
1. Investigate the surface preparation effect on the strength of the adhesive joint. 2. Strength comparison of sago glue with other wood adhesives available in
market.
CHAPTER 2
LITERATURE REVIEW
2.1 Introduction
Stress distribution in adhesive is one of the important parameter to be considered before applying an adhesive to a selective substance. The stresses in the adhesive occur when the adherent cannot hold the excess loading applied on it. Although the strength of adhesive joint still far behind from other method of joining, the research for the reliable and high strength for adhesive joint still on demand.
R. D Adam et al in book Structural Adhesive Joint in Engineering [3] stated that it is convenient now to define an adhesive as a polymeric material which, when applied to surface, can joint them together and resist separation. A structural adhesive is one used when the load required to cause separation in substantial such that the adhesive provides for the major strength and stiffness of the structure. The structural members of the joint, which are joined together by the adhesive, are the adherends, a word first used by de Bruyne (1939).
2.2 Type of Stress
Type of stresses that usually involve in adhesive bonding are tensile stress, shear stress, cleavage stress and peel stress. Beside than these, as stated by A. J Kinloch [l], adhesive often operate with some additional stress in the joint arising from shrinkage of the adhesive relative to the substrate. R. D Adams, et al [3] stated that the maximum adhesive stress always occur near the end of the bond line.
(a)
Y
Figure 2.2 : Types of stress to which an adhesive joint may be subjected: (a) Tensile Shear; (b) tensile loading; (c) cleavage; (d) peel
Definition for each of 4 main stresses in adhesive bonding [4] :
a. Tensile stress : Exerted equally over the entire joint straight and away from the adhesive bond
b. Shear stress : Always across the adhesive bond. The bonded materials are being force to slide each other.
c. Cleavage stress : Always concentrated at one edge and exerts a prying force on the bond.
d. Peel stress : concentrated along a thin line at the bond's edge. One surface is
flexible. Most applications combine stresses.
All the stress mentioned above should be though as the design consideration before designing the structure of the adhesive joint. The structure design should be able to minimize the 4 main stresses mentioned. From the observation of A. B. Pereira and A. B. de Morais [5] in their research about Strength of adhesively bonded stainless steel joints, they found that , shear stress distributions are almost uniform in the double lap joints and belief that peel stresses are not relevant in double-lap joints, even when thick adherends are used, thus reducing internal bending effects. While both peel and highest shear stresses act simultaneously on the same edge of double
lap joint specimens.
2.3 Variation in Adhesive Bonding
A lot of research has been done in designing the adhesive bonding. Each of the design has been produce to suit the application of the materials. Each design has its own advantages and disadvantages in dealing with the adhesive stress that has been discuss earlier.
Adhenaro Arch nr: rý
(a) Simplc Lap Joint
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c) Rehated Lap Joint
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(b) Tapered Lap Joint
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(c) Double Strap Joint (f) Double Strap Joint
Figure 2.3a: some common engineering adhesive joint [6]
From all the design above, the simple lap joint or also known as single lap joint is the joint that may need an adherend surface preparation before been bond. The tensile stress test will be investigated for this study.
R. D. Adams at al [3], in book of structural adhesive joint in engineering stated that some design are stronger than others, but none is simpler to make than the single - lap. However, the bevel, step and butt - strap have the advantage of presenting at
least one external smooth surface. Scarfing or tapering is of limited benefit since Thamm (1976) has shown that the adherends have to be tapered to a fine edge if significant benefit is to be achieved, and this is usually impracticable.
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