Materials and Design 34 (2012) 279–284

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Materials and Design

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Technical Report

Optimum conditions for field vulcanizing a fabric conveyor beltwith a better capability of elongation

Chuen-Shii Chou a,⇑, Ching-Liang Liu a,b, Chun-Sheng Tseng a

a Powder Technology R&D Laboratory, Department of Mechanical Engineering, National Pingtung University of Science and Technology, Pingtung 912, Taiwanb Maintenance Raw Material Handling & Inplant Transportation Dept., China Steel Corporation, Kaohsiung 812, Taiwan

a r t i c l e i n f o a b s t r a c t

Article history:Received 18 June 2011Accepted 4 August 2011Available online 11 August 2011

0261-3069/$ - see front matter � 2011 Elsevier Ltd. Adoi:10.1016/j.matdes.2011.08.009

⇑ Corresponding author. Tel.: +886 8 7703202x701E-mail addresses: cschou@mail.npust.edu.tw (C

npust.edu.tw (C.-L. Liu).

Using ANOM of the Taguchi method, the optimum conditions for field vulcanizing a fabric conveyor beltwith a better capability of elongation were obtained. The optimum conditions included: (1) curing time of25 min, (2) curing pressure of 9 kg/cm2, (3) dismantling platen temperature of 90 �C, and (4) forcedcooling of air. Under these optimum conditions, a confirmation experiment was carried out, and theaverage elongation of this spliced fabric conveyor belt was 503.17%. The percentage contribution of eachcontrollable factor within the current investigation range was also determined via ANOVA of the Taguchimethod. Interestingly, of the four controllable factors the cooling method was the most influential on theelongation capability of the vulcanized area, and its percentage contribution was 46.26%. This study val-idated the importance of the cooling method although most reports about vulcanizing a fabric conveyorbelt gave more importance to the curing time and pressure.

� 2011 Elsevier Ltd. All rights reserved.

1. Introduction

A conveyor belt is usually used to transport raw materials (suchas ores, and grains) over a short or medium conveying distance. Forexample, in an iron-making plant, the blast furnace is called the‘‘heart’’ of the plant while the conveyor belts are called the ‘‘bloodvessels’’ of the plant. The reasons for this are that conveyor beltsare simple in construction, flexible in transport system configura-tion, and versatile in use, and that they may also be used to trans-port goods over a considerable distance [1]. Two types of conveyorbelt (fabric belt and steel cord belt) are designed and fabricated forcustomers’ demand for bulk solids handling. Specifically, the fabricconveyor belt, which has the advantages of low cost and easymaintenance, is widely used.

However, in terms of industrial safety, the sudden rupture of aconveyor belt will cause the rapid fall of a conveyor’s counter-weight (or weighting box), and this fallen object may endangerthe workers. Aside from this, all fallen materials and the dustpollution need to be dealt with, and these accidental disasters willresult in great loss to the company. Because the belt is a key com-ponent of the conveyor belt system [2], its reliability (or materialproperties) can substantially influence the safety and performanceof a conveyor belt system. Therefore, research on conveyor beltsystems has attracted considerable attention.

ll rights reserved.

6..-S. Chou), n9832007@mail.

In the past, several methods have been proposed to improve theperformance and safety, to predict the behavior, or to extend thelifetime of a conveyor belt system. For example, Kozhushko andKopnov studied the fatigue behavior of three types of fabricconveyor belt subjected to shear loading and proposed a modelof fatigue strength function [3]. Huang et al. presented a method,based on measuring the tensile force–length characteristic curveof the steel-cord belt splice, to forecast the breakage of a steel-cordbelt splice [4]. Rengifo reported a splice assembly technique basedon using a ‘‘grooved rubber matrix’’ for a wire reinforced conveyorbelt [5]. Fourie et al. used the method of digital X-ray imaging tomonitor the fabric conveyor belting [6]. Lodewijks and Owes devel-oped a belt conveyor inspection tool based on fuzzy logic to objec-tify the inspection results [7]. Mazurkiewicz developed a computersystem for monitoring conveyor belt joints [8] and experimentallyanalyzed the aging impact on the strength of the adhesive sealedjoints of conveyor belts [1]. Further, Hou and Meng measured thedynamic elastic modulus, viscous damping, and rheologicalconstants of the belt and proposed these properties as a functionof the tensile loading on the belt [2].

Most interestingly, Kozhushko and Kopnov indicated that thetypes of failure of a fabric conveyor belt include abrasive wear ofthe boards and rubber covers, breakage of fabric, the divergenceof joints, etc. [3]. Rengifo also reported that the splice of a fabricconveyor belt is the weakest part of a conveyor belt system [5].The intranet database of China Steel Corporation (CSC) betweenJanuary 2007 and December 2009 shows that the number ofdamaged fabric conveyor belts, which need to be re-spliced, is

Table 1Controllable factors and their levels.

Factor Description Level 1 Level 2 Level 3

A Time of curing (min) 25 15 40B Pressure on belt (kg/cm2) 7 5 9C Temperature of dismantling platen (�C) 60 30 90D Cooling method Natural Water Air

Table 2Test conditions.

Time ofcuring(min)

Pressureon belt(kg/cm2)

Temperature ofdismantlingplaten (�C)

Coolingmethod

Test 1 25 7 60 NaturalTest 2 25 5 30 WaterTest 3 25 9 90 AirTest 4 15 7 30 AirTest 5 15 5 90 NaturalTest 6 15 9 60 WaterTest 7 40 7 90 WaterTest 8 40 5 60 AirTest 9 40 9 30 Natural

280 C.-S. Chou et al. / Materials and Design 34 (2012) 279–284

56. This number is second only to that of damaged fabric conveyorbelts due to cutting. Therefore, improving the elongation capabilityof the splice in a fabric conveyor belt is worthy of continued study.

Aside from these, the optimum conditions of splicing a fabricconveyor belt have seldom been investigated using the Taguchimethod [9]. This fact is the main motivation behind this investiga-tion. Moreover, an attempt to study the percentage contribution ofeach experimental parameter to the splicing (or vulcanizing)process has seldom been undertaken. Accordingly, in this study,the time of curing, the pressure acting on the fabric conveyor belt,the temperature of dismantling platen from the fabric conveyorbelt, and the cooling method were used as the controllable factors.The optimum conditions for vulcanizing a fabric conveyor beltwith a better elongation capability in the spliced area and thepercentage contribution of each aforementioned experimentalparameter to the vulcanizing process were determined using theTaguchi method [9].

2. Taguchi method

The Taguchi method [9] has generally been adopted to optimizethe design parameters [10–19] because this systematic approachcan significantly minimize the overall testing time and the exper-

Table 3The S/N ratio of each test.

Test A B C D ePA (%)

Y1 Y2 Y3

1 1 1 1 1 426 412 4022 1 2 2 2 424 426 4343 1 3 3 3 435 458 4044 2 1 2 3 351 353 3555 2 2 3 1 356 357 3626 2 3 1 2 384 381 3827 3 1 3 2 409 421 4148 3 2 1 3 372 371 3749 3 3 2 1 314 331 317

Note: Y1, Y2 and Y3 represent the elongation of the first, second and third test pieces (cut frsecond and third test pieces (cut from the rest part of the spliced area), respectively. Thtests.

imental costs. Using the orthogonal array specially designed for theTaguchi method, the optimum experimental conditions can beeasily determined. This study considered four controllable factors,and each factor had three levels (Table 1). Therefore, an L9(34)orthogonal array was chosen, and the experimental conditions(Table 2) were obtained by combining Table 1 and the L9(34)orthogonal array. Accordingly, an analysis of the signal-to-noise(S/N) ratio was needed to evaluate the experimental results. Usu-ally, three types of S/N ratio analysis are applicable: (1) lower isbetter (LB), (2) nominal is best (NB), and (3) higher is better(HB). Because the target of this study was to maximize the elonga-tion capability of the spliced area in a fabric conveyor belt, the S/Nratio with HB characteristics was required, given by

SN¼ �10 log

1n

Xn

i¼1

1Y2

i

!ð1Þ

where n is the number of repetitions under the same experimentalconditions, and Y represents the result of measurement (i.e., Y is theelongation of the spliced area).

The analysis of mean (ANOM) statistical approach was adoptedherein to construct the optimal conditions. Initially, the mean ofthe S/N ratio of each controllable factor at a certain level must becalculated. For example, ðMÞLevel¼i

Factor¼I; the mean of the S/N ratio offactor I in level i, was given by

ðMÞLevel¼iFactor¼I ¼

1nIi

XnIi

j¼1

SN

� �Level¼i

Factor¼I

" #j

ð2Þ

In Eq. (2), nIi represents the number of appearances of factor I in

level i, and SN

� �Level¼iFactor¼I

h ij

is the S/N ratio of factor I in level i, and its

appearance sequence in Table 3 is the jth. By the same measure,the mean of the S/N ratios of the other factors in a certain levelcould be determined. Thereby, the S/N response table wasobtained, and the optimal conditions were established. Finally,the confirmation experiments on vulcanizing process under theseoptimal conditions were carried out.

In addition to ANOM, the analysis of variance (ANOVA) sta-tistical method was also used to analyze the influence of eachcontrollable factor on the process of vulcanizing a fabric con-veyor belt. The percentage contribution of each factor, qF, wasgiven by

qF ¼SSF � ðDOFF VErÞ

SST� 100 ð3Þ

In Eq. (3), DOFF represents the degree of freedom for each factor,which is obtained by subtracting one from the number of the levelof each factor (L). The total sum of squares, SST, was given by

eSA (%) 16

P6i¼1Yi

MSD (�10�6) S/N

Y4 Y5 Y6

451 443 424 426.33 5.53 52.57445 451 443 437.17 5.24 52.81542 570 610 503.17 4.22 53.74472 470 590 431.83 5.99 52.22418 455 484 405.33 6.37 51.96584 573 497 466.83 5.09 52.93442 541 461 448.00 5.12 52.91527 538 533 452.50 5.37 52.70528 443 429 393.67 7.22 51.41

om the patched area), respectively. Y4, Y5 and Y6 represent the elongation of the first,e boldface red font corresponds to the maximum value of S/N ratio among the nine

C.-S. Chou et al. / Materials and Design 34 (2012) 279–284 281

SST ¼Xm

j¼1

Xn

i¼1

Y2i

!j

�mnðYTÞ2 ð4Þ

where YT ¼Pm

j¼1ðPn

i¼1YiÞj=ðmnÞ, m represents the number of exper-iments carried out in this study, and n represents the number ofrepetitions under the same experimental conditions. The factorialsum of squares, SSF, was given by

SSF ¼mnL

XL

k¼1

ðYFk � YTÞ2 ð5Þ

where YFk is the average value of the measurement results of a

certain factor in the kth level. Additionally, the variance of error,VEr, was given by

VEr ¼SST �

PDF¼A

SSF

mðn� 1Þ ð6Þ

Fig. 1. Schematics and Dimensions (unit: mm) of a fabric conveyor belt. (a) Astripped fabric conveyor belt with a stepped surface, (b) two patched areas(5 � 60 cm2) on the top and bottom of a cohered fabric conveyor belt, and (c) acohered belt made by splicing the ends of two pieces of the fabric conveyor belt.

3. Materials and methods

3.1. Splicing a fabric conveyor belt

In this study, the fabric conveyor belt made by San Wu Rubber(SWR) Mfg. Co., Ltd., Taiwan was used. It consisted of a top sty-rene–butadiene-rubber (SBR) with a thickness of 6 mm, a bottomSBR with a thickness of 2 mm, and a core of polyester fabric withthe strength of EP150 � 4. Aside from this, the total length, width,and thickness of the fabric conveyor belt used in the experimentsof vulcanization were 75.0, 60.0, and 1.3 cm, respectively. Theprocedure of splicing the ends of two pieces of the fabric conveyorbelt is as follows. (1) Before overlapping two pieces of fabric con-veyor belt, for one belt, its top SBR of 475 mm in length was peeledoff, and its fabric core was stripped to be a stepped surface(Fig. 1a); (2) for the other belt, its bottom SBR of 475 mm in lengthwas peeled off, and its fabric core was stripped to be a stepped sur-face, too; (3) the surface of these two stripped fabric conveyor beltswas grinded using a portable grinding machine and then cleanedusing a cleaning fluid (REMA TIP TOP R4); (4) the rubber cement(SWR A35-NR) and the tie rubber (SWR A35-NR) were used tomake these two stripped fabric conveyor belts cohere (Fig. 1b);(5) two gaps with an area of 5 � 60 cm2 on the top and bottomof this cohered fabric conveyor belt were patched using the coverstock (SWR A49-NR/SBR) (Fig. 1b); and (6) this cohered fabricconveyor belt (Fig. 1c) was then placed in the vulcanizing equip-ment (Canada’s Shaw-Almex Co., KD 2600 � 5600), as shown inFig. 2, and it was vulcanized at a temperature of 140 �C [20] witha preset pressure and duration (Table 2).

3.2. Measuring the elongation of a spliced fabric conveyor belt

After the experiment of vulcanization, this spliced fabricconveyor belt was removed from the vulcanizing equipment byreleasing the pressure acting on the belt and dismantling the pla-ten on the belt. According to CNS K6344 [21], CNS K6343 [22],and JIS K6301 [23], the procedure of measuring the elongation ofa spliced fabric conveyor belt is as follows. (1) A dumb-bell-shapedtest piece with a length of 100 mm was cut from the spliced area(or patched area) of the fabric conveyor belt (Fig. 3a), and itsdimensions, which are identical to those of the dumb-bell-shapedtest piece of pattern No. 3 depicted in CNS K6344 [21] and JISK6301 [23], are shown in Fig. 3b; (2) one end of this test piecewas clamped to one jig of a tensile testing machine, and the otherend of this test piece was clamped to the other jig of the tensiletesting machine (Fig. 3c); and (3) the tensile testing machine was

turned on, this test piece was pulled with a speed of 500 mm/min, and the elongation was registered before this test piece wasruptured (Table 3). In this study, three test pieces were cut fromthe patched area of the fabric conveyor belt, and three test pieceswere cut from the rest part of the spliced area of the fabricconveyor belt (Fig. 3a). These six test pieces were used for measur-ing the elongation of a spliced fabric conveyor belt, and the mea-sured values are listed in Table 3.

The elongation of a dumb-bell-shaped test piece was deter-mined by [21,23]

e ¼ LS � L0

L0ð7Þ

In Eq. (7), L0 and LS represent the original length of the parallelsection of dumb-bell (20 mm) and the stretched length of the par-allel section of dumb-bell before this test piece is ruptured,respectively.

Fig. 2. Schematic of a vulcanizing equipment.

Fig. 3. Schematic of the spliced fabric conveyor belt (a), the dimension of a testpiece with a dumb-bell shape (unit: mm) (b), schematic of a tensile testing machineclamping a test piece (c).

Table 4S/N ratio response table.

Factor/Level ½ðSN ÞLevelFactor�j ðMÞLevel

Factor

j = 1 j = 2 j = 3

A/1 52.57 52.81 53.74 53.04A/2 52.22 51.96 52.93 52.37A/3 52.91 52.70 51.41 52.34B/1 52.57 52.22 52.91 52.57B/2 52.81 51.96 52.70 52.49B/3 53.74 52.93 51.41 52.70C/1 52.57 52.93 52.70 52.74C/2 52.81 52.22 51.41 52.15C/3 53.74 51.96 52.91 52.87D/1 5257 51.96 51.41 51.98D/2 52.81 52.93 52.91 52.88D/3 53.74 52.22 52.70 52.89

Note: The boldface font corresponds to the maximum value of the mean of the S/Nratios of a certain factor among the three levels.

282 C.-S. Chou et al. / Materials and Design 34 (2012) 279–284

4. Results and discussion

4.1. Optimum conditions

The elongations of the spliced and patched areas in a fabric con-veyor belt prepared in Tests 1–9 were measured according to themethod, as shown in Section 3.2, and their values were presentedin Table 3. Substituting the number of experimental repetitionsand results of the measurement (i.e., the elongations of the splicedand patched areas) into Eq. (1), the S/N ratio of each test conditionwas determined (Table 3). The boldface red font in Table 3 refers tothe maximum value of S/N ratio among the nine tests. Subse-quently, the values of the S/N ratio were substituted into Eq. (2)and the mean of the S/N ratios of a certain factor in the ith level,ðMÞLevel

Factor; was obtained (Table 4). In Table 4, the boldface red fontrefers to the maximum value of the mean of the S/N ratios of acertain factor among three levels, and thus it indicates one of theoptimum conditions for vulcanizing a fabric conveyor belt.

From Table 4, the optimum conditions of splicing (or vulcanizing)a fabric conveyor belt with a better capability of elongation are asfollows. (1) The time of curing is 25 min; (2) the pressure acting onthe fabric conveyor belt is 9 kg/cm2; (3) the temperature of disman-

tling platen from the fabric conveyor belt is 90 �C; and (4) the coolingmethod is air cooling. The aforementioned optimum conditions areidentical to the test conditions in Test 3. Therefore, the confirmationexperiment was carried out according to the aforementioned opti-mum conditions with the exception of the cooling method (Test10 in Table 5), the elongations of the spliced and patched areas wereregistered, and the S/N ratio was calculated (Table 5).

The value of the S/N ratio in Test 10 (53.17) was slightly smallerthan that under the optimum conditions (53.74), but the averageelongation under optimum conditions (503.17%) substantially ex-ceeded that in Test 10 (457.84%), as shown in Table 5. This resultis probably attributed to the fact that for a fixed curing time, a fixedtemperature of dismantling platen, and a fixed pressure acting onthe fabric conveyor belt, the forced cooling (such as air cooling)can more homogeneously cool the vulcanized fabric conveyor belt,compared with the natural cooling. Nozu et al. experimentally andnumerically studied the cure process of a solid rubber (such asSBR), and they indicated that the cure reaction was clearly en-hanced after the heat addition to the rubber had been removed[24]. Therefore, a faster cooling through forced air may result inhigher elongation values compared with the natural cooling. Inter-estingly, this result is very exciting due to the fact that under a nor-mal operation, if the vulcanized area has a higher averageelongation, this fabric conveyor belt may have a longer lifetime.

The chemical process of vulcanization is a type of cross-linkinginitiated by heat or pressure [25]. During the vulcanization, someof the C–H bonds of one polymer chain of the SBR are replacedby chains of sulfur atoms that link with another polymer chain.The cross-link can be a covalent bond or an ionic bond. If thereare more cross-links with a higher number of sulfur atoms in thevulcanized area, this vulcanized fabric conveyor belt may havegood dynamic properties, which are important for flexible move-ments of the rubber [25].

Aside from this, Schmidgall indicated that because the ends of aconveyor belt must be joined together to create a continuous belt,operators must use the utmost care when employing either of twocommon splicing methods (i.e., vulcanizing and mechanical fasten-ers), and for the permanent splicing of a conveyor belt, vulcanizingis most often the best choice [26]. Therefore, the optimum condi-tions of splicing a fabric conveyor belt presented herein is the verypractical and valuable information for on-site vulcanization of afabric conveyor belt.

4.2. Percentage of contribution

Initially, YFk (the average value of the measurement results of a

certain factor in the kth level) was obtained from Yi in Table 3, and

Table 5S/N ratios in Test 3 (i.e. optimum) and Test 10.

A B C D ePA (%) eSA (%) 16

P6i¼1Yi

MSD (�10�6) S/N

Y1 Y2 Y3 Y4 Y5 Y6

Test 3 1 3 3 3 435 458 404 542 570 610 503.17 4.22 53.74Test 10 1 3 3 1 447 433 423 459 479 506 457.84 4.82 53.17

Table 6YA

k , YBk , YC

k and YDk .

YAk YB

k YCk YD

k

Level 1 455.56 435.39 448.56 408.44Level 2 434.67 431.67 420.89 450.67Level 3 431.39 454.56 452.17 462.50

Table 7SSF and qF.

Factor SSF qF (%)

A 0.94 26.64B 0.06 1.84C 0.89 25.26D 1.63 46.26

C.-S. Chou et al. / Materials and Design 34 (2012) 279–284 283

they are listed in Table 6. By substituting YFk and YT ¼ 440:54% into

Eq. (5), the factorial sum of squares, SSF, for each factor was calcu-lated individually, and they are listed in Table 7. Using Eq. (4), thetotal sum of squares, SST, was determined. By substituting SSF andSST = 3.52 in Eq. (6), the variance of error, VEr, was obtained. Finally,by the substitution of SSF, SST = 3.52, VEr = 0.03, and DOFF = 2 in Eq.(3), the percentage contribution of each factor, qF, was determinedsequentially; and these values are presented in Table 7.

At a fixed vulcanizing temperature of 140 �C the rank order ofthe percentage contributions of each factor was as follows: (1)the cooling method (46.26%), (2) the time of curing (26.64%), (3)the temperature of dismantling platen from the fabric conveyorbelt (25.26%), and (4) the pressure acting on the fabric conveyorbelt (1.84%). The cooling method was the most influential factoron the elongation of the spliced fabric conveyor belt among thefour controllable factors. Aside from this, the average S/N ratiosof the cooling method in D1 (natural cooling), D2 (water cooling),and D3 (air cooling) were 51.98, 52.88, and 52.89, respectively (Ta-ble 4). This result indicated that during the vulcanization theforced cooling was better than the natural cooling, and the aircooling was slightly better than the water cooling because thethermal conductivity of air (0.024 W/m �C) is significantly smallerthan that of water (0.58 W/m �C). Nozu et al. also indicated that thecooling process played an important role in the cure process, andthe heating time might be reduced by considering the preciseconsiderations for the cooling mechanism [24].

The curing time was the second influential factor on the elonga-tion of the spliced fabric conveyor belt among the four controllablefactors, and its percentage contribution was 26.64%. Aside fromthis, the average S/N ratios of the curing time in A1 (25 min), A2(15 min), and A3 (40 min) were 53.04, 52.37, and 52.34, respec-tively (Table 4). Karaa gac et al. indicated three periods of curingrubber, which included: (1) induction, (2) curing, and (3) over-cure[27]. They also indicated that in the third period the reversion,equilibrium, or marching cure behaviors might occur. This maybe used to explain that the average S/N ratio of A3 (52.34) wasthe smallest among the three levels of the controllable factor A(i.e., curing time). Because the reversion usually has an undesirableeffect on the product quality, to optimize the curing processbecomes necessary [27,28].

The temperature of dismantling platen was the third influentialfactor on the elongation of the spliced fabric conveyor belt amongthe four controllable factors, and its percentage contribution was25.26%. Aside from this, the average S/N ratios of the temperatureof dismantling platen in C1 (60 �C), C2 (30 �C), and C3 (90 �C) were52.74, 52.15, and 52.87, respectively (Table 4). A lower tempera-ture of dismantling platen corresponds to a longer waiting period,under which the reversion may occur in the spliced fabric conveyor

belt. Therefore, as the temperature of dismantling platen increasedfrom 30 to 90 �C the average S/N ratio increased from 52.15 to52.87.

Aside from this, Bando indicated that the minimum vulcanizingtime for a fabric conveyor belt was 15 min, and the vulcanizingtime was linearly proportional to the thickness of a fabric conveyorbelt [20]. Schmidgall also indicated that for a smooth surfaceacross the joint, a substantial curing time was generally required[26]. Moreover, the pressure acting on the fabric conveyor beltwas the least influential factor on the elongation of the spliced areaamong the four controllable factors because the pressure usedherein followed the suggestion that the hydraulic pressure actingon the fabric conveyor belt during vulcanization should range from7 to 10 kg/cm2 [20].

5. Conclusion

Using the vulcanizing method and the analysis of mean (ANOM)of the Taguchi method, this investigation studied the optimumconditions of splicing (or vulcanizing) a fabric conveyor belt witha better capability of elongation, and the average elongation of thisspliced fabric conveyor belt reached 503.17%. Moreover, thepercentage contribution of each controllable factor to splice (orvulcanize) a fabric conveyor belt was determined by the analysisof variance (ANOVA) of the Taguchi method, and the most influen-tial factor was the cooling method whose percentage contributionwas 46.26%. Most importantly, this study supports the applicationof a simple and traditional vulcanizing method to effectively splicea fabric conveyor belt with a better capability of elongation on-site,and it may help to substantially reduce the manufacturing cost.

Acknowledgment

The authors would like to thank San Wu Rubber (SWR) Mfg. Co.,Ltd., Taiwan for assisting this research.

Reference

[1] Mazurkiewicz D. Analysis of the ageing impact on the strength of the adhesivesealed joints of conveyor belts. J Mater Process Technol 2008;208:477–85.

[2] Hou YF, Meng QR. Dynamic characteristics of conveyor belts. J. China Univ MinTechnol 2008;18:0629–33.

[3] Kozhushko GG, Kopnov VA. Fatigue strength functions in shear loading offabric conveyor belts. Int J Fatigue 1995;17:539–44.

[4] Huang M, Li G, Li E, Wei R. Real-time monitoring of steel-cord belt splicebreakage and tension super-threshold. Bulk Solids Handl 2002;22:204–8.

[5] Rengifo PE. New splice assembly technique for wire reinforced belting. BulkSolids Handl 2004;24:24–30.

284 C.-S. Chou et al. / Materials and Design 34 (2012) 279–284

[6] Fourie JH, Alport MJ, Basson JF, Padayachee T. Condition monitoring of fabric-reinforced conveyor belting using digital x-ray imaging. Bulk Solids Handl2005;25:290–4.

[7] Lodewijks G, Owes JA. Belt conveyor inspection tools based on fuzzy logic. BulkSolids Handl 2005;25:284–9.

[8] Mazurkiewicz D. Computer system for monitoring conveyor belt joints. CanMin J 2007;5:24.

[9] Taguchi G. Introduction to quality engineering. New York, USA: McGraw-Hill;1990.

[10] Bounou M, Lefebvre S, Do XD. Improving the quality of an optimal power flowsolution by Taguchi method. Electric Power Energy Syst 1995;17:113–8.

[11] Wang SB, Pan C. Two-phase flow instability experiment in a natural circulationloop using the Taguchi method. Exp Therm Fluid Sci 1998;17:189–201.

[12] Wu DH, Chang MS. Use of taguchi method to develop a robust design for themagnesium alloy die casting process. Mater Sci Eng A 2004;379:366–71.

[13] Chiang KT. Optimization of the design parameters of parallel-plain fin heatsink module cooling phenomenon based on the taguchi method. Int CommunHeat Mass Trans 2005;32:1193–201.

[14] Erzurumlu T, Ozcelik B. Minimization of warpage and sink index in injection-molded thermoplastic parts using taguchi optimization method. Mater Design2006;27:853–61.

[15] Wang TY, Huang CY. Improving forecasting performance by employing thetaguchi method. Eur J Operat Res 2007;176:1052–65.

[16] Chou CS, Ho CY, Huang CI. The optimum conditions for comminution ofmagnetic particles driven by a rotating magnetic field using the taguchimethod. Adv Powder Technol 2009;20:55–61.

[17] Chou CS, Lin SH, Peng CC, Lu WC. The optimum conditions for preparing solidfuel briquette of rice straw by a piston-mold process using the taguchimethod. Fuel Process Technol 2009;90:1041–6.

[18] Chou CS, Yang RY, Chen JH, Chou SW. The optimum conditions for preparingthe lead-free piezoelectric ceramic of Bi0.5Na0.5TiO3 using the taguchi method.Powder Technol 2010;199:264–71.

[19] Chary GHVC, Dastidar MG. Optimization of experimental conditions forrecovery of coking coal fines by oil agglomeration technique. Fuel2010;89:2317–22.

[20] Bando. Guide to field splicing of fabric conveyor belt. Bando ChemicalIndustries, Ltd.; 1993 (93C0610-114).

[21] Metrology & Inspection, ROC. Method of test for tension of vulcanized rubber.Bureau of Standards; 1985 [CNS K6344].

[22] Metrology & Inspection, ROC. General rules of physical testing methods forvulcanized rubber. Bureau of Standards; 1996 [CNS K6343].

[23] Japanese Standards Association. Physical testing methods for vulcanizedrubber; 1971 [JIS K6301-1971].

[24] Nozu Sh, Tsuji H, Itadani M, Fujiwara W, Ohnishi K. Study of cure process ofthick solid rubber. J Mater Process Technol 2008;201:720–4.

[25] Mark JE, Erman B, Eirich FR. The science and technology of rubber. 3rded. Burlington MA: Elsevier Academic Press; 2005.

[26] Schmidgall N. Belt splicing: vulcanized or mechanical?. Pit & Quarry. QuestexMedia Group, Inc.; 2003

[27] Karaa gac B, Inal M, Deniz V, Inal M, Deniz V. Artificial neural networkapproach for predicting optimum cure time of rubber compounds. MaterDesign 2009;30:1685–90.

[28] Han IS, Chung CB, Lee JW. Optimal curing of rubber compounds with reversiontype cure behaviour. Rubber Chem Technol 2000;73:101–3.