Alignment problems of timber production in Architecture-Engineering-Construction Projects

Abstract

Due to the negative effects of the carbon-dioxide on theecosystem, the Architecture-Engineering-Construction industriesare looking for the new materials with lower carbon-footprint.One of the best natural materials that can be used in AECindustries is wood and its derivatives. However, due to thephysical and chemical properties of timber, the application of itin AEC industries, especially in the process of manufacturing andproduction, encounter with some difficulties and obstacles; andthey are causes of decreasing the speed and increasing the costof production in AEC industry. The most important problem in theprocess of off-site manufacturing of the wooden pieces is causedby the differences between dimensions of pieces in drawings withthe dimensions of it that need to be set for the workshopmachinery. These changes are not only necessary in the process ofsawing pieces, but also in the other processes such as assemblingand making the details. Therefore, during the process ofmanufacturing and production of the wooden pieces, there are alot of changes on the dimensions of a component in the productiondrawings and they negatively affect the manufacturing processand, hence increasing the cost and delaying in production. Theaim of this research was to find and identify the reasons ofthese changes in order to mitigate the risks. The researchadapted a desktop study followed by direct observations in orderto identify the major problems and obstacles. The results showedthe problems are mostly due to the tacit nature of designknowledge and lack of proper knowledge of the designers about theactual process of timber production. This research is a noviceattempt for expediting timber production process in order toleverage sustainable and modern methods of offsite manufacturingoriented construction.

Keywords: IBS, Timber, Drawing, Manufacturing process,Architectural design, off-site Manufacturing

1. Introduction:

This research was motivated with the first author’s backgroundprofessional experience regarding the obstacles and barriers inproduction and manufacturing of wooden furniture andconstructional components. The author has been acting as theowner and director of an interior design and wooden componentmanufacturing company for nearly 20 years. The most important ofthose problems was the necessity of changes in the architecturaldrawings of the wooden pieces at the early stage ofmanufacturing; and it was not only the cause of a lot of seriousarguments between manufacturing skilled workers and designers,but also slowing down and sometimes stopping the process ofproduction and finally leading to the noticeable losses.Nevertheless, using any possible methods such as replacement ofthe workforce with the new one there was no any success on thematter. The eager to doing the research on the said topic becamemuch more when the author became an investigator and inspector ofthe government in AEC sector and it provided an opportunity toget access to the information about the other woodenmanufacturing companies in Iran; and surprisingly all of themwere encountered with the problems of not matching architecturaldrawings with the technical drawings. Some of manufacturers evenmade a lot of changes on the process of production throughspending noticeable investment on the purchasing new woodproduction machinery in order to mitigate the aforementionedproblems. Surprisingly, most of the wooden component andfurniture manufacturers had been included to allocate the fixedbudget (5-15% of their turnover) on the matter (the losses thatcome from the differences of the architectural drawings with theworkshop drawings) as a part of annual expenditures of thecompany. In some cases, this issue caused bankruptcy of thecompany in long term. The importance of this matter was as muchthat it became an issue for all managers and owners in woodindustry sector and they were trying to mitigate the problem byany possible methods. In some cases, this matter and

disadvantages of it on the loss-and-gain put the companies on thecritical situation; and in order to survive they decided toremove the design and architecture department from the company.Some of them, as a solution, even attempted to replace thedesigners with the skilled manufacturing workers; however therewas no improvement in this case also. When during someconferences, exhibitions and annual professional wooden andtimber industries meetings in the other countries in which thefirst author represented Iranian government (e.g. in Germany,Turkey, Russia, France, UAE, Malaysia, Iraq, Pakistan, Armenia,Kuwait,) the intellectual discussions proved that this problemexists in the other countries also. As such, the main motivationof the this study was first to investigate and identify the typesof such alignment problems in timber industry and then try tofind solutions for mitigating the problems.

2. Literature Review

Due to the alignment problems of timber production in AECindustry, there is a high level of waste in the use of wood andtimber as one the most important natural resources. According to“The United Nation’s Food and Agriculture Organization (FAO),total global round wood production has increased from 2,463million m3 1970 to 3,358 million m3 in 1994 (roughly a 1.3%increase per year). While some predict that sufficient woodfibers will be available in the future globally others projectsignificant gaps in supply chain. Apsey and Reed quantify thisgap as some 400 million m3 in 2010 and nearly 600 million m3 in2020 and Nilsson puts the numbers at 800 million m3 and 900million m3 for the same dates, respectively. From 1970 to 1994,the worldwide consumption of wooden panels increased by about2.9% annually, to a total volume of 126.4 million m3 in 1994.According to FAO, the rate of growth is expected to stay above2.0% annually for the next decade, resulting in an estimatedconsumption of 172.6 million m3 in 2010. For this reason, woodenfurniture and component manufacturers and face increased need fortheir raw material and upward pressure on raw materialprices”(Buehlmann, Ragsdale, & Gfeller, 2000). On the other

hand, there has been proven a significantly low constructionalcost for a timber building (6- 15%) compared to similar housesconstructed by prefabricated concrete or steel. (Stehn &Bergstro, 2002), availability and ease to work, flexibility,good performance under influence of wind and earthquake, naturalbeauty, inexhaustible supply and its structural properties. Inoverall timber in compared with stone and concrete can be usedfor either tension or compression stresses(Hunt, 2012) and it hasbecome the causes of increasing the usage of it in manyconstruction sectors such as railroad and bridge and many otherapplication (Kozem Šilih & Premrov, 2010).Nevertheless, anincrease on the demand of timber and shortage of its resources asa raw material in worldwide the studies show that during theprocess of the manufacturing wooden components 7% up to 40-50% ofthe annual supply of timber raw material is wasted as a residuesand it is caused of 2-8% of turnover as loss(Daian & Ozarska,2009). In addition every year the noticeable money are spent onthe maintenance of timber buildings and much of them because ofthe mistakes of designers or builders for example in the UAS,Californians are spent nearly 364 million USD annually on thismatter(Morrell, 2002). In according with the above reasons inorder to survive the domestic and overseas wooden componentmanufacturers, managers, experts and companies must remove thebarriers and difficulties of the wooden off-site manufacturingand it is essential to reassess their working behaviors and toredesign and to reequip themselves to take a part and to competein a dynamic environment. To achieve this goal it is required tooperate the integrated manufacturing system and to use theaspects of product design, production engineering and qualitycontrol and to remove the barrier of the production in woodenindustry sector(Pegler & Kochhar, 1988). The aim of this researchwas to find and identify the obstacles and barriers of woodenoff-site manufacturing in order to decreasing the number ofmistakes and the delay on process of production that altogetherare caused of increasing the production cost and decreasing thespeed of wooden component production.

3. Research Methodology

To achieve to this goal, we investigate the barriers anddifficulties of 30 Iranian wooden component/ wooden furniturecompanies based on direct observation, constructed interview anda survey of the practices and performance of them in prior of the1990-2011. To more understanding and finding the problems andtheir reasons we took the views of the personnel in all timberproduction process. We also investigated the losses- gainaccount’s records of companies in relating to timber production’sproblems.

4. Results and discussion

During the product process of timber components there are manyphases that are included planning, concept, system-level-design,detailed design, testing and production ramp-up(Rodríguez, deCiurana, & Elías, 2005). The product development process needs acorrected and different levels of involvement by importantfunctions of the individual sections such as design section,analysis section, first necessary material preparation section,cutting section, assembling section, quality control section andfinally delivery section. In general, after finishing the designprocess the architectural drawings are passed to the productionsection for manufacturing. In this stage, the skilled workers andexperts start to calculate and to analyze the drawings toidentify the production essential materials such as wood andjoints. They also identify the essential production time. Then,ordering the necessary manufacturing material to the materialpreparation department. After preparation the materials, thecutting section’s personnel start to cut the wooden material andthen, pass the cutted pieces to the assembling to manufacture theproduct and finally after quality controlling the product willdeliver to costumer. In one hand with the consideration of theprocess of production of timber and wood from the naturalresource (forest) and on the other hand, its physical andchemical properties and the necessary of the industrial machineryin manufacturing an production of the wooden constructionalelements. The most ideal method is off-site manufacturing and thesame as the other industrial products and materials the

production and application of it in AEC industries needs toproceed the following stages:

design Department

Production Department

Quality Control

Department

Product Store

DepartmentDelivery

DepartmentInstalation Department

StoreDepartme

-Analyzing of architectural drawings to calculatethe essential production materials and equipment.-estimating the necessary production time.-Taking the acceptance of design department for necessary changes on drawings to set up for use wooden machinery.

-Site visit-Making measurement.-Early sketches.-Taking the viewand acceptance of client.-Final checking.-Calculating theproduct price.-The acceptance of manager.

-Preservation and conservation of produced goods.-Prioritize the goods in

-checking quality control.-Checking packaging quality.-Issuing the

-Wooden raw materials.-Production equipment.-Cutting tools.-Fixtures.-Dies and

-Check in and out the produced goods.-Load in andout the products.

--Checkingthe dimension and quality ofthe produced product.-Installati

Fig 1. The diagram of wooden pieces Manufacturing process, Source: Authors

However, according to the direct observations from the casestudies(30 wooden component manufacturing companies), we foundthat the application of it in AEC industries especially in theprocess of manufacturing and production is encountered with somedifficulties and obstacles and it has become an issue for theconstructional experts and managers to find a solution for it.The main barriers and problems that are caused a lot ofdifficulties in wooden manufacturing process are as following:

4.1. The necessity of making changes on the dimension ofarchitectural drawings to set for wooden machinery

One of the most important problems in the process of off-sitemanufacturing of the wooden pieces is “The differences betweenArchitectural and Engineering drawings with the workshopdrawings”. In accordance with the instruction of the woodenindustrial machinery, there are many differences between thedimensions of architectural and engineering drawings of a woodenpiece to set for using by the wooden machinery in a workshop orfactory. It means that to produce a wooden piece in the factorythe dimensions of the Architectural drawings need to change. Forinstance, if the dimensions of a wooden piece in theArchitectural drawings are as following, the essential dimensionsof the above piece for cutting with sawing machinery with thethickness of 2 mm saw will be:

50 cm

0.2 0.2

0.2

50 cm

50.4

Fi2. The differences between the dimension of a wooden piece in Architectural Drawing and workshop drawings in manufacturing process

The reasons of the above changes refers to making the piece withthe shape of rectangle, the piece needs to be sawed 1 time fromeach side and due to the rectangle has 4 sides so for making theshape of rectangle the piece altogether needs to be sawed 4 timesfrom sides. On the other hand, in sawing every side of the woodenpiece, the sawing machinery decrease 2 mm because of thethickness of its saw. Thus to achieve the 50 cm breadth thementioned corrected breadth of the piece in drawings should be50 + 2 ( 2mm ) =50.4 cm and with the corresponding calculationfor the length of 70 cm, the mention corrected length in drawingsfor setting for wooden machinery is 70+2(2mm)=70.4cm. The abovenecessary changes to the dimensions of wooden piece are just forsawing process. Whereas, there are another essential changes onthe dimensions of the wooden piece to set any wooden machinerysuch as edge banding machine and milling machine. For example, ifwe want to add the PVC Edge band to the edge of the piece weshould add the essential calculations of the edge banding machinebased on its instruction of the PVC edge banding machine to thedimensions of the piece in Architectural drawings. Furthermore, awooden product is contained some or many pieces and changes whichmentioned above should be done for all of them separately. Theabove changes are necessary not only in the sawing process ofpieces but also in the other process such as assembling andmaking the details. Thus, in the manufacturing process of thewooden pieces, there are a lot of changes in architecturaldrawings and these changes will cause to some negative effects as

0.2

70 cm70.4 cm

70 cm

following on the production process and finally lead toincreasing the cost and decreasing the speed of production in AECindustries:

4.1.1. The slowdown of production process Basically careful calculation needs time spending and in theduration of the manufacturing process it is counted as a negativefactor and leads to the delay on manufacturing process.

4.1.2. The growth of mistake possibility

Due to the high variety and high proportion of the analyses andcalculations for necessary changes of the architectural drawingsfor setting for the wooden machinery, the possibility of makingmistakes is increased and it has a lot of disadvantages on thisprocess.

4.1.3. Reduction of the architectural quality, foundations and principles Due to the lake of information of the personnel in themanufacturing and production sectors from the foundations of thearchitectural design, sometimes the changes of the architecturaldrawings lead to removing the foundations of the architecturaldesign such as forms, rhythm, concinnity, symmetry, composition,harmony and continuity from the products.

Before After

Fig3.Removing the architectural foundation of design is resulting from the changes on the drawings in the factory.

4.2. The changes of locations, specifications of details

Due to the dimension’s limitations of the wooden pieces,sometimes it is necessary to make the changes on the factors suchas locations, thickness, connection between pieces. For example,maximum available dimensions of a wooden panel that is used inwooden industry in accordance with the particle board’s dimensionis (3.66 cm × 221 cm), whilst sometimes the mentioned dimensionsin architectural drawings is more than 366 cm 221 cm (425 cm × 246cm) and it as an unexpected work which leads to changing thedetails, extra work and stopping the production process to makethe changes and take the permission of the design sector.

Before After

Fig9.The diminution limitation of the wood can be caused of changed in the form, color, jointsand thickness of the wooden pieces.

4.3. The changes of the structural specifications of pieces

In general, in the production process of wooden componentsespecially in wooden furniture production process there is noviewpoint of structural engineering analysis and the design isdone based on the general knowledge of the designer aboutstructures and sometimes, it leads to changes in thearchitectural and engineering drawings. For instance, due to thechange which is existing in form and the stiffness of a woodenelement by the thickness of 16 mm and length more than 150cm ,

366 425 cm 59 cm

246 cm

25 cm

221 cm

there is not any possibility of usage of it in this conditionspecially in the vertical position or as the foundation of theother pieces (Criswell, 1990).

Thickness of 16 mm

Fig10.Lake of structural data can be caused of changes on theshape and physical properties of the wooden pieces.

4.4. The changes of the locations and specifications of thejoints

Joints can be counted as the weakest part of timber structure andthe loss of properly performance of them lead to global stiffnessof the timber structure and an increase of the assembledelements’ dimension (Chen, Lee, & Jeng, 2003). The qualitativeand quantitative properties of the wood have the directiveeffects on the design of the details and joints and sometimes theway of joints of the wooden pieces leads to some changes on thearchitectural and engineering drawings. For example, installationof a hinge on the wooden pieces with the thickness of below 8 mm

is impossible. While, sometimes the mentioned thickness inarchitectural drawings is below than 8 mm.

150 cm

L ≥ 150 cm

45 cm

The least thickness of the wooden piece must be ≥ 8 mm

Fig11.The wooden details need to the essential dimension and physicalproperty of the wooden pieces. Source : Author

4.5. The changes of the specifications and the properties of thewooden pieces

Because of the differences of the mentioned specification in thearchitectural drawings, with the available real specificationsmaking the change on the specifications of the product isessential. For example, some colors that designer mentioned inthe drawings does not produce and available at all.

The design mentioned color The available color

Fig12.The shortage of available color is caused of change in architectural drawings.

4.6. The changes in the final dimension of product and dividingit to the smaller pieces

Because of delivery limitations it is essential to divide theheavy and big pieces to the light and smaller ones to prevent thewooden pieces against the damage in delivery process.

Fig 13. Dividing the long length to short length to make it deliverable .Source: Author

4.7. The changes in the forms and design of the wooden pieces

Because of impossibilities or difficulties of making some formssuch as arc by wooden materials the change on the forms and shapeof components is necessary.

BeforeAfter Fig14. The necessary change of form of the wooden component before and afterproduction process

4.8. The changes in the final dimensions or the specifications ofproduct

Because of the limitation on the installation place, sometimes itis necessary to make a change on the specifications of theproduct based on the condition of installation place. Forexample, in humidity areas the manufacturer must add the water

12 m 6 m 6 m

Prof Stuffs to the wooden components or change the hill’s heightand it may leads to a change in the color or the used material.

Fig 15.The Changes of the colors and height ofwooden pieces before and after productionprocess

To find and focus more and deep on the topic, we have taken theviews of the managers, designers, production engineers, qualitycontrol engineers, skilled workers, deliverers and installers. Wehave found that all of the personnel in production department aredealing with the changes on the architectural drawings and it hasbecome a critical problem for the all 30 companies. We also havefound that in some companies in which the designers have beenworking for more than 5 years over there continuously, the numberof the changes in the process of the manufacturing is much lowerthan the others. In addition, in a few of the companies that wereusing the full Automatic Wooden Machinery (CNC) in comparisonwith the others ( Manual/ CN wooden machinery)due to thenecessity of using the computer knowledge to making the changeson the architectural drawings the problem was much complicated.Furthermore, in five of the companies that were using the skilledworkers instead of the designers in comparison of the others thenumber of the changes on the architectural drawings has been twothird of the others. Interestingly, in these five companies theskilled workers were designing two times for a product. One ofthem is for the general design and the other one for productionprocess. Two of the companies’ managers had decided to send someof their skilled workers to architectural trainings as a solutionof the problem.

5. Conclusion

Whilst there is an increasing tendency to apply timber as anacceptable replaced material with the lower carbon foot print inAEC projects, it is important to increase the application of itthrough removing the difficulties and barrier of timberproduction process.We have proved that the most main problem in timber off-sitemanufacturing process is the differences between thearchitectural drawings with the workshop drawings. We have alsoproved that this difficulty comes from Lake of information ofdesigners involve wooden Industry that leads to increasing theproduction cost and decreasing the production speed. Therefore weconclude that to remove the timber production’s problems, it isessential to arrange the training subjects for designers aboutthe way of manufacturing timber components in off-sitemanufacturing in AEC projects. The designers involve in woodenAEC industries and projects also need to know the necessaryspecifications of wooden components to be set up for woodenmachinery. On the other hand this will likely enhance the abilityof wooden components producers and firms to exist and compete inlocal and foreign markets by lifting the level of performance ona variety of objectives.

6. References

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