Optimum Design and Manufacture of Wood Products

473 Pages·2019·23.575 MB·English

by  Etele Csanády, Zsolt Kovács, Endre Magoss, Jegatheswaran Ratnasingam

Etele Csanády · Zsolt Kovács ·
Endre Magoss ·
Jegatheswaran Ratnasingam
Optimum
Design and
Manufacture of
Wood Products
Optimum Design and Manufacture of Wood
Products
á á
Etele Csan dy Zsolt Kov cs Endre Magoss
(cid:129) (cid:129) (cid:129)
Jegatheswaran Ratnasingam
Optimum Design
and Manufacture of Wood
Products
123
EteleCsanády Zsolt Kovács
Department ofWood Engineering WoodandPaper Technology
SoproniEgyetem/University of Sopron SoproniEgyetem/University of Sopron
Sopron, Hungary Sopron, Hungary
Endre Magoss Jegatheswaran Ratnasingam
Department ofWood Engineering Department ofForest Products
SoproniEgyetem/University of Sopron University PutraMalaysia
Sopron, Hungary Seri Kembangan, Malaysia
ISBN978-3-030-16687-8 ISBN978-3-030-16688-5 (eBook)
https://doi.org/10.1007/978-3-030-16688-5
LibraryofCongressControlNumber:2019936293
©SpringerNatureSwitzerlandAG2019
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To the Memory of Great Woodworkers of the
past and present.
Foreword
Bothnatureandmankindhavestrivenforyearstousenaturalorartificialprocesses
toachieveanoptimumorbestoutcome.WhileNaturehastheinherentcapabilityto
organizeitsphenomenaoptimally,mankindhastodevelophisapproachesbasedon
scientific considerations and derivations supported by experimental measurements.
Around 1770, Lagrange developed mathematical methods for seeking optimal
solutions and originated the formulation of an “Optimal Column”. At the present
time,strictmathematicalmethodsforoptimizationareavailablefornonlinearcases
with constraints. At the same time, the general use of optimization procedures has
not been adopted in design and manufacture.
Themoderatesuccessinoptimizationmayhaveitsbackgroundintherelatively
complicated use of strict mathematical methods for engineers and in the lack of
proper functional relationships describing the system’s behaviour as a function of
influencing variables. The existence of functional relationships is crucial in any
optimization procedure to get reliable optimum solutions. Another problem may
arise when a large and complex system should be optimized. In this case, some
functional relationships are always lacking or they cannot be formulated with
acceptable accuracy. A way out from this situation may be to divide the whole
systemintosubsystemsallowinganeasierhandlingofthesmallerandmoredefinite
subsystems.
ThepresentworkOptimumDesignandManufactureofWoodProductsisafirst
attempt to summarize the existing scientific methods and to present new develop-
ments and results in this field. First of all, a large array offunctional relationships
was elaborated and described indetailsinChap.2. Besides thestrict mathematical
method,anengineeringoptimizationapproachisalsooutlinedanddemonstratedin
severalexamples.Theessenceofthisapproachliesintherecognitionthatinmany
cases, the optimum is uniquely determined by a particular constraint. In this case,
the optimization procedure is highly simplified with the further possible benefit of
allowingustogetageneralanalyticalsolutionwhichhasafundamentaladvantage
over single numerical solutions because a general solution allows a quick decision
in the case of conflicting optimums.
vii
viii Foreword
Iwouldliketoemphasizetheimportanceofcolourandglosspropertiesofwood
as its most important aesthetic properties. Their practical use in design and man-
ufactureofwoodproductsisfarfromtherealpossibilities.Theelaborationofmore
practical evaluation methods and representations using the measured reflection
spectrum may help to widen the use of these important properties. Colour modi-
fication plays a distinct role in value adding of several timber species.
Inorder topromotetheuse ofoptimization methods asan indispensable design
tool,itwouldbedesirabletoorganizespecialcoursesatuniversitiesonthesubject
Mathematical and Engineering Methods of Optimization helping engineers to
become more familiar with this topic.
Thematerialpresentedinthisbookisdesignedforabroadcircleofgraduateand
postgraduate students, researchers and application engineers working on optimum
design and manufacture of wood products.
Sopron, Hungary György Sitkei
Preface
The world trade of furniture has grown tremendously in the last decades which
requires the economic utilization of natural resources and production capacities.
High-quality timber materials are becoming increasingly scarce, and therefore,
optimal solutions in design and manufacture are an urgent need. Concerning mass
production, the manufacturing technology has been revolutionized in the last
decade where large machinery and computers have taken over craftsmanship,
significantly increasing the production rate. The common technologies include
computer-aided design (CAD) and manufacturing (CAM) using CNC centres or
through-feed machine line.
Further attempt should be made, however, in the optimization of structural
design and manufacturing processes in order to achieve a more economical use of
existingresources.Moreover,thepreferreduseofvalue-addingmethodsforthefull
realization of aesthetical values of timber materials is another important way to
fulfil customer demand.
PresentworkonOptimumDesignandManufactureofWoodProductsprovides
comprehensive treatment and discussion of mathematical and engineering opti-
mization procedures with many numerical examples. In order to facilitate the for-
mulation of objective functions and constraints in equality and inequality forms, a
wide array of functional relationships is presented based mostly on our own
experimental results. A newly developed “Mechanics of Upholstering” is also
included which facilitates the optimum selection of cushioning materials and sup-
port comfort design.
Adetailedoverviewofcurrentpracticesindesignoffurnitureisalsopresented.
The different existing methods for strength design, the interaction of tolerance and
machining accuracy are also discussed and illustrated with several numerical
examples. For a quick selection of furniture joints, new similarity equations are
presented and elaborated.
In the final chapter, the discussion of general principles of furniture manufac-
turing processes is described. Interrelations among product structure, degree of
automation, inventory and batch size are also explained. The description of main
woodworking operations, surface coating and finishing, as well as value-adding
ix
x Preface
technologies,roundsupthistopic.Aspecialcareispaidtothecross-referencingof
each chapter, which is presented in strong relation to each other. In Appendix,
selected colour pictures demonstrate the unique ornamental properties of wood
materials.
TheauthorsareespeciallyindebtedtoProf.G.Sitkeiforreadingthemanuscript
and offering useful suggestions in working out practical examples using engi-
neering optimisation suggested by him. Thanks also goes to Dr. Zoltán Kocsis for
offering help in the preparation of illustrations. The authors are also sincerely
grateful to the staff of Springer Verlag for their excellent cooperation.
Sopron, Hungary Etele Csanády
Sopron, Hungary Endre Magoss
Sopron, Hungary Zsolt Kovács
Seri Kembangan, Malaysia Jegatheswaran Ratnasingam
Contents
1 Overview of Problems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Product Design and Development . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Manufacturing of Products. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2 Functional Relationships. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.2 Purpose and Role of Functional Relationships . . . . . . . . . . . . . . 11
2.3 Classification of Functional Relationships. . . . . . . . . . . . . . . . . . 13
2.4 Cutting Force and Energy Requirement . . . . . . . . . . . . . . . . . . . 14
2.4.1 Knife Machining . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.4.2 Sanding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.5 The Tool Life Equation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
2.6 Roughness Relationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
2.6.1 Roughness Characterization . . . . . . . . . . . . . . . . . . . . . 36
2.6.2 Anatomical Characterization of Wood . . . . . . . . . . . . . . 39
2.6.3 Interrelations Among Roughness Parameters . . . . . . . . . 46
2.6.4 The Use of Structure Number. . . . . . . . . . . . . . . . . . . . 51
2.6.5 Effect of Machining on the Surface Roughness . . . . . . . 57
2.6.6 Influence of Wetting on Surface Roughness. . . . . . . . . . 71
2.7 Mechanics of Upholstering . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
2.7.1 Upholstering Material Properties . . . . . . . . . . . . . . . . . . 75
2.7.2 Mechanical Behaviour of Soft Tissue . . . . . . . . . . . . . . 84
2.7.3 Numerical Examples. . . . . . . . . . . . . . . . . . . . . . . . . . . 89
2.8 The Hardness of Wood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
2.9 Abrasion Resistance Property. . . . . . . . . . . . . . . . . . . . . . . . . . . 102
2.10 Wetting Properties of Wood Surfaces. . . . . . . . . . . . . . . . . . . . . 106
2.11 Colour Properties of Woods. . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
xi