Fatemeh SARFI, Majid AZIZI, Amin ARIAN

A multiple criteria analysis of factors affecting markets of engineered wood products with respect to customer preferences: a case study of particleboard and MDF

Fatemeh SARFI, Majid AZIZI?, Amin ARIAN

Department of Wood and Paper Sciences and Technology, Faculty of Natural Resources, University of Tehran, Karaj 31585-4314, Iran

Of considerable importance and a principal goal in business is the creation of customer satisfaction. Evaluation of end user preferences for producers of particleboard and medium density fi berboard (MDF) requires indices for the assessment of markets and modif i cation of product quality. However, only sporadic research has been carried out in this fi eld. Therefore, the goal of this survey was to identify indices with respect to the points of view of: 1) consumers in order to select particleboard and MDF, 2) suppliers in order to consider production strategies, improve product quality,improve competitive ability of domestic producers in the market and help industry to be more customer oriented. This survey consisted of two stages. In the fi rst stage, factors affecting customer preferences in the selection of particleboard and MDF were determined using a Delphi method, with the help of experts and a group of principal users of these products. Then these factors were categorized in three groups: qualitative, technical and technological and marketing factors.Furthermore, questionnaires were prepared and distributed among consumers and responses evaluated and weighted by using an analytic hierarchy process (AHP) using expert choice software. Our results show that at both stages, the consistency ratio was less than 0.1, indicating that all results and judgments were stable and acceptable. The results obtained from questionnaires about particleboard rank the priorities for factors in the selection by consumers as follows:nail and screw holding ability, homogeneity in structure, edge strength of panel, durability and bending strength. The most important factors for MDF were machinability of panels, homogeneity in structure, nail and screw holding ability,edge strength of panel, durability and bending strength.

particleboard, medium density fi berboard (MDF), customer satisfaction, AHP, market

?Author for correspondence (Majid AZIZI)

E-mail: mazizi@ut.ac.ir

Introduction

During the last decade particleboard in Iran has experienced an increase in production (FAO,2010; Iran’s Customs, 2010; Iran Wood Industries Association, 2010). By establishing new production lines, developing and reconditioning old lines, production capacity and production volume have increased considerably. However, with the current high market pressure and a large demand from domestic market in Iran, new plants and increased capacities are under consideration. Medium density fiberboard (MDF), a new and specialized product given its enormous capacity for different usage in furniture manufacturing, has received much attention and has a very high market potential (Poorkaveh, 2007). Therefore, it is necessary to specify effective indices on consumer preferences about particleboard and MDF and the degree of importance attached to a number of factors and then convey these specif i cations to the manufacturers and suppliers of these two products in order for them to adjust their management policies.

Nuolivirta (2006) investigated the effective factors on selecting wood based panels and found that the most important factors are durability,moisture resistance, screw holding ability, surface softness and machinability. From the point of view of consumers, Wong and Kozak (2008)explained that physical factors, i.e., machinability,panel stability, joint strength and glueability, are more important in MDF. Arian (2008) explained the preferences of particleboard consumers in the Iranian market as follows: stability in quality,surface smoothness, product availability in the market, panel homogeneity, price fl exibility, durability, exact dimensions, nail and screw holding ability, moisture resistance, price, machinability,bending strength, internal bond and formaldehyde content. In a survey on indices of the Iranian market, Poorkaveh (2007) found that the consumption of MDF, as a new wood based panel product in the domestic market, has increased at a rapid rate compared with other wood based panels. She mentioned that the entry and use of this new product in the market affected the consumption of other types of particleboard, which resulted in competition for particleboard in the MDF market. Burnaz and Topcu (2005) evaluated the factors affecting customer preferences in the beverage industry for the Cola brand by using a Delphi procedure; after gathering questionnaires and combining expert opinions, they found that effective factors included brand, price and availability. Arian (2003) investigated the MDF market and its effect on particleboard and showed that production and consumption of particleboard have grown in the last decades.

Considering the effect of particleboard and MDF on domestic markets as well as relative competitive position in some applications, we attempted to evaluate the factors affecting the selection of particleboard and MDF from the point of view of consumers in Iran. We used the analytical hierarchy process (AHP), one of the more important methods in decision making, for specifying the weights of these factors. Our purpose was 1)to recognize the effective indices from the point of view of the consumer in the selection of particleboard and MDF and 2) to assign a degree of importance to each of these factors in home and off i ce furniture industries. Conveying these effective factors and their degree of importance to producers and suppliers of particleboard and MDF can help them adjust their production strategies,in order to increase the quality of products and the competitive position of domestic producers in the market.

Materials and methods

Brief description of factors

In this section a brief description of each of the factors is presented.

1 First group: qualitative factors.

Qualitative factors, such as machinability and surface quality, play an important role in selecting products.

1.1 Machinability: working simply with the panel,such as sawing and molding the panel with various cutting devices (e.g., saw).

1.2 Surface quality: quality of panel surface from the point of view of smoothness, thickness homogeneity, scratch strength and absence of impurities.

1.2.1 Surface smoothness: absence of waves,twists, blisters, notches, bowing, big particles and impurities, i.e., small stones, metal and other external material on the surface of the panel.

1.2.2 Thickness tolerance: homogeneity of thickness in all parts of a panel.

1.2.3 Surface strength: strength of surface against impact, scratch and crush.

1.2.4 Impurities in the panel: absence from panel surface of every kind of stain or discoloration,making panels undesirable as a product, such as: 1) black stains incurred from bark and rotten wood; 2) stains as the result of an aggregation of glue, paraffin and oily material on the panel surface; 3) discoloration caused by remaining too long under the hot press; 4) other stains and discolorations.

1.2.5 Surfacing ability: the ability of panel surfaces to be used for different fi nishing and lamination.

1.3 Glueability: ability of panel for absorbing adhesives.

1.4 Strength of edges: strength of panel edges against rupture and chipping during cutting processes.

1.5 Homogeneity: homogeneity of density and panel properties in different areas.

1.6 Durability: strength to withstand biological agents, such as fungi rot, insect borers and weathering over time.

2 Second group: technical and technological factors.

This group includes properties related to mechanical strength and physical properties.

2.1 Nail and screw holding ability: ability of panels to hold screws, nails and other joints.

2.2 Mechanical properties: strength of panels against mechanical forces, i.e., bending and tensile forces.

2.2.1 Bending strength: strength of panels against bending forces.

2.2.2 Tensile strength: strength of panels against tensile forces parallel with the surface of a panel and perpendicular to a panel, showing its internal bond.

2.3 Physical properties: resistance of panels against physical agents, such as air humidity and water absorption.

2.3.1 Moisture resistance: resistance of panels against humidity in the air.

2.3.2 Water absorption and thickness swelling:resistance of panels against water absorption and increases in thickness by absorbing water, describing the stability of panel against absorption of water.

2.4 Density: one of the most important factors determining the entire set of characteristics of a panel. In most cases, increases in density are accompanied by an increase in physical and mechanical properties of a panel, although it might cause more weight, a decrease in machinability and a loss in the simplicity of its use.

2.5 Exact dimensions: compatibility of nominal and real dimensions and squareness of panel edges.

2.6 Formaldehyde emission: less free formaldehyde emission from the panel and a better formaldehyde emission class, i.e., E1 standard.

3 Third group: marketing factors.

This group includes all effective factors in the domestic market of Iran for these two products.

3.1 Price: referring to all factors which are related to the price of panels.

3.1.1 Selling price: panel price.

3.1.2 Price stability (absence of price fluctuation): maximum stability in the sale price of products during the time of the sale, indicating that the increase and decrease of prices during the year are minimum.

3.1.3 Flexibility of price and terms of payment:the flexibility of sellers in price and payment terms. 1) Discount: amount of discount that the seller considers for retail or wholesale consumers;2) terms of payment: fl exibility on the part of the seller in terms of payment, such as cash payment,credit payment and installment payments.

3.2 Sale service: all services performed by sellers after panel sales, such as verifying objections, reliability of delivery, place and time of delivery.

3.2.1 After-sale services: verifying customer objections after selling panels and responsibility of sellers against possible buyer objections related to quality of sold panels and their suitability in new production.

3.2.2 Delivery reliability: delivery of panels sold to customers on dates specif i ed, i.e., without delay.

3.2.3 Delivery time: speed in delivery of purchased panels and short delivery time.

3.2.4 Delivery place: delivery of purchased panels at point of sale, at the place of consumer or at production site.

3.3 Variety of dimension and thickness: production and presentation of panels with different dimensions and in different thicknesses based on the request and requirement of customers, since these products are used in the manufacture of different products.

3.4 Brand: meaning the prestige and name of the producer.

3.5 Stability in quality: durability and retention of quality of panels under different usage.

3.6 Availability: easy access to panels in the market during all seasons, from factories and retail stores (Arian and Bayat, 2004).

Methods

In order to study the factors considered in the selection of particleboard and MDF, the fi rst step was to establish the factors involved. To reach this goal in our fi eld survey, we prepared a list of probable factors affecting consumer preferences.We then questioned several professional experts(25 persons) in this field as well as managers of several furniture manufacturing plants in the country (60 persons) who are the major consumers of particleboard and MDF. The Delphi method was used for final recognition of factors and at the end, 36 effective factors and sub factors in consumer preferences were extracted. They were further divided in three major groups as follows:1) fi rst group: qualitative factors; 2) second group:technical and technological factors; 3) third group:marketing factors. From this, we built an hierarchy with the help of AHP in order to specify the weight of each factor. Figure 1 shows the structure of the hierarchy of the effective factors in the selection of particleboard and MDF from the point of view of consumers.

After classifying the factors and providing a hierarchy tree, a questionnaire was designed and distributed. As well as seeking statistical advice,the people interviewed for this study included big furniture producers in Iran, which are users of large amounts of particleboard and MDF. After scrutinizing the questionnaires, the data acquired was evaluated with the use of AHP.

The AHP, one of the most comprehensive systems, is designed for decision making with multiple scales. With its use, decisions that depend on different or multi criterion decisions can be pursued. With this technique, formulation of the problem with a hierarchy process and spotting questions at different qualitative and quantitative scales are possible. This process considers different choices in decision making and allows sensitivity analysis on scales and subscales. Based on binary comparisons, judgments and calculations by this method become simpler. By using AHP, at fi rst a hierarchy tree is designed with regard to the question of this study. This hierarchy tree usually includes several levels; the fi rst level describes the targets of the method of decision making, the middle level shows the factors which are the measures of comparing options and the last level implies the choices that are compared.Then the factors introduced into the decision making process are compared with each other and weights or values are specif i ed for each factor(Ghodsipoor, 2003).

其中，F(xiàn)itness表示用適度函數(shù)值來(lái)評(píng)價(jià)仿真一致性達(dá)到過(guò)程中全局一致性水平；參數(shù)β1與β2可依據(jù)問(wèn)題實(shí)際情況適當(dāng)調(diào)整ID（DEy與SD（DEy D）值。仿真與優(yōu)化結(jié)果，將得到全局最優(yōu)的群決策重要參數(shù) δ*，C*，（y=1，2，…，r，k=1，2，…，xy，

After computing the average of all cells of binary comparison matrices, normalization of the results was carried out; given the compilation of the weights of low level ingredients with high level ingredients in the hierarchy, the weight of factors and sub factors was obtained.

An important point about binary comparison matrices is their consistency ratio; according to Saaty (2000), the consistency ratio of matrices should be less than or equal to 0.1 in order to maintain the stability and reliance of judgments.Hence, if in some binary comparison matrices this ratio is more than 0.1, it is necessary to repeat the judgment for the stability of matrices, after which the averages of cells of comparison matrices are recalculated. We used the expert choice software in this study in order to obtain the weight of factors and sub factors.

Results and discussion

After comparing the degree of importance of these related factors, with an emphasis on consumer preferences by using the expert choice software, factor weights were specif i ed. It should be mentioned that at all stages the consistency ratio was less than 0.1 and all results and judgments were stable and acceptable. Gained results and preference sequences at different levels for particleboard and MDF are shown in Table 1.

Binary comparison matrices at different levels for particleboard and MDF

Factors affecting the selection of particleboard and MDF and their weights are listed in Table 1.As shown in this table, qualitative factors about particleboard were categorized as the most important group of factors, technical and technological factors came in second and marketing factors in third place of importance. Among the qualitative factors, surface quality occupied the first place, followed by homogeneity of structure, the strength of panel edges, durability, machinability and glueability. Among the technical factors,nail and screw holding ability was identified as the foremost factor and mechanical and physical strength, exact dimensions, density and less formaldehyde emission factors were ranked lower.Among the marketing factors, stability in quality was recognized as the most important factor from the point of view of consumers, while factors of price, availability, variety in dimension and thickness, services and brand were ranked lower.

Comparison of indices between particleboard and MDF

As shown in Fig. 2, the factors affecting the manufacturing of particleboard show that nail and screw holding ability (0.099), homogeneity of structure (0.096), edge strength of panel (0.084),durability (0.071) and bending strength (0.063)were factors with higher priority compared to other factors and categorized in the first to fifth rank. The remaining factors were of lesser importance. Figure 2 also shows that factors related to marketing were accorded lowest priority and existed in the last rank.

Similarly in the case of MDF, Fig. 3 shows that both machinability and homogeneity of structure(0.095) had highest priority, followed by nail and screw holding ability (0.076), strength of panel edges (0.071), durability (0.069) and bending strength (0.065) were categorized in the second to fi fth rank. Other factors were accorded lower priority. Again, factors related to marketing were of the least important.

Comparing Figs. 2 and 3, it is seen that machinability in MDF was more important than for particleboard, which might be due to the fact that in most applications, high machinability of MDF is very important and needed. In the case of particleboard it is diff i cult to maintain their machinability; most of the time it is used for interior panneling or as veneered framework and hence nail and screw holding ability is more important for particleboard. Our results indicated this also and showed that customers did not require machinability of particleboard.

Homogeneity as a factor, in both particleboard and MDF, was categorized in second place, indicating that it was recognized as one of the most important factors. With regard to wood based panels, both structural compatibility and homo-geneity had a significant effect on the quality of furniture produced.

Table 1 Weight of factors affecting the selection of particleboard and MDF

Fig. 2 Final result of factors affecting the selection of particleboard with respect to customer preferences

Another effective factor for MDF was nail and screw holding ability (Fig. 3), suggesting that for consumers of MDF, greater nail and screw holding ability and other kinds of joints from this product were required. Edge strength, durability and bending strength were other effective factors in consumer preferences for particleboard and MDF (Figs. 2 and 3), which in applications of both products were very effective, especially the edge strength of panels. Because of having high machinability, high strength of edges is necessary for both particleboard and MDF in order to cooperate with rupture of edges and decrease wastage.

As shown in Figs. 2 and 3, indices of both products, relating to marketing, such as payment terms, delivery time, discounts, reliance on delivery, after-sale services and place of delivery were ranked as the last six places from the point of view of importance.

Conclusions

Our results show that nail and screw holding ability in the case of particleboard and machinability in the case of MDF were the fi rst priority in the selection of these two products by consumers.After-sale service, one of the most important indices in other industries, in the opinion of experts,was considered the last priority, showing its lack of importance in the wood based panel industry in Iran.

Fig. 3 Final result of factors affecting the selection of MDF with respect to customer preferences

Arian A. 2003. Evaluation of Medium Density Fiberboard marketing and its effect on particleboard marketing in Iran. Dissertation. Azad University, Tehran, Iran.

Arian A. 2008. Evaluating customer preferences and customer satisfaction measurement in Iranian particleboard market. Internatinal Panel Products Symposium, Espoo,Finland.

Arian A, Bayat A. 2004. Evaluation of customer satisfaction from Neopan Khalkhal Co. & competitors in CSI method. Commercial Department, Neopan Khalkhal Co., Tehran, Iran.

Asgharpoor M. 1999. Multi Criteria Decision. Tehran University, Tehran, Iran.

Burnaz S, Topcu I. 2005. A Multi Criteria Decision Model for Turkish Soft Drink Industry. ISAHP, Honolulu, Hawaii.

FAO. 2010. FAO statistical database. http://www.fao.org/. Accessed 1 December 2010.

Ghodsipoor H. 2003. Analytic Hierarchy Process. Amirkabir University, Tehran, Iran.

Iran’s Customs. 2010. External Commercial Statistics Books. Iranian Ministry of Commerce Publications, Tehran, Iran.

Iran Wood Industries Association. 2010. Statistic of MDF& particleboard’s production, import and export for years 1999–2009. Association of Iran Wood Industries Employer, Tehran, Iran.

Nuolivirta P. 2006. The end-user preferences of particleboard. MDF and OSB, EPF. Savcor Indufor Ltd, Finland.Poorkaveh H. 2007. Evaluation of particleboard’s marketing undevelopment factors in Iran. Dissertation. Tehran University, Tehran, Iran.

Saaty T. 1999. Fundamentals of the Analytic Network Process. ISAHO, Kobe, Japan.

Saaty T. 2000. Decision Making for Leaders. RWS Publications, Pittsburgh.

Wong DC, Kozak RA. 2008. Particleboard performance requirements of secondary wood products manufacturers in Canada. Forest Prod J, 58(3): 34–41.

11 December 2011; accepted 9 March 2012