Reducing Fan Blade Vibration in Rice Harvesters and Combine Harvesters by Applying Product Grouping

Transcription

1 Reducng Fan Blade Vbraon n Rce Harvesers and Combne Harvesers by Applyng Produc Groupng Kchoe Supakumnerd 1, a, Phareepnas Phmpsan 2, b, Chachapol Chungchoo 3, c * and Pcha Asadamongkon 1, d 1 Deparmen of Mechancal Engneerng, Faculy of Engneerng, Srnakharnwro Unversy, Nakhon Nayok, 26120, Thaland. 2 Naonal Meal and Maeral Technology Cener, 114 Naonal Scence Park, Klong Nueng, Klong Luang, Paumhan, 12120, Thaland. 3 Deparmen of Mechancal Engneerng, Faculy of Engneerng, Kasesar Unversy, Bangkok, 10900, Thaland. 3 ORCID: Absrac Currenly, several housand of rce harvesers and combne harvesers are assembled every year. These harvesers are sold whn Thaland and expored o he CLMV and Souh Asan counres. However, one of he major clams of hese producs s broken bols a he connecon beween fan blade and fan shaf. The nvesgaon ndcaed ha a cause of hs falure s hgh vbraon of a fan un. In order o elmnae hs falure, vbraon conrol of he fan un s requred. However, a producon lne s a lo of me consumpon for balancng a fan un of hese harvesers because operaors mus do boh sac and dynamc balancng processes for every sngle fan un. Accordng o he prmary nvesgaon, he varaon n poson and dmenson of he fan blade s a major cause of s unbalance. In order o reduce hs varaon, a new sandard procedure was nroduced. Ths procedure was developed based on an assumpon ha he vbraon of he fan un can be sgnfcanly decreased f he sandard devaon of he fan blade s wegh s reduced. Expermenal resuls ndcaed ha he new procedure can reduce me consumpon for dong sac and dynamc balancng processes of he fan un sgnfcanly. For example, n case of a 4-f fan un, he oal assembly me of he fan un can be reduced for more han 50%. Currenly, hs new procedure has been used n several producon lnes. Keywords: Fan blade, rce harveser, combne harveser, vbraon, produc groupng (Fgure 1) o he CLMV and Souh Asan counres. I was recorded ha here were many caasrophc falures a he fan blade and a major cause of hs falure was he vbraon of fan blade un. Hence, manufacurers aemped o reduce he vbraon of fan blade un by decreasng he varaon of fan blade wegh. Fgure 2 shows a sold model of he fan blade un. Each un consss of wo ses of fve fan blades, hree ball bearngs wh vbraon absorber, four ses of blade holder, and one shaf. A real fan blade can be seen n Fgure 3. Accordng o he prmary nvesgaon, he varaon n poson and dmenson of he fan blade s a major cause of s unbalance. Ideally, hs problem can be fxed by dong he sac and dynamc balancng processes nroduced by several expers [1-5]. However, hs mehod consumes a lo of producon me. Hence, he oher mehods ha spend less producon me are requred. The new mehod ha can serve hs requremen s herefore nroduced n hs paper. INTRODUCTION More han 10 years ha Tha s manufacurers have produced and expored her rce harvesers and combne harvesers Fgure 1. An example of combne harveser 3105

2 Fgure 2. Sold model of fan blade un CASE STUDY Fgure 3. Example of fan blade There are several models of rce harvesers and combne harvesers ha are sold n he markes. However, n hs research, a fan un ha s used n boh 4-f model of rce harveser and 4-f model of combne harveser produced by a Tha s manufacurer was seleced as a case sudy. The deals of each fan blade used n he 4-f model are shown n Fgure 4, whle he deals of each se of fan blades are shown n Fgure 5. Fgure 4. Drawng of each fan blade 3106

3 The GD&T of pars of 4-f model of rce harveser, ncludng dmenson and angulary, mees he ISO 2768 Sandard [6]. There s no any specfc GD&T From he forh assumpon, he schemac of mass represenng he fan blade can be shown n Fgure 7. I was also sad ha he varaon n angles a 15 and 90 of fan blade geomery affecs he dsance r 1 o r 10 and angle Ɵ 1 o Ɵ 10 whch s menoned n Fgure 5 and Fgure 6. Fgure.5 Drawng of one se of fve fan blades Schemac of case sudy Accordng o Fgure 2, he schemac of 4-f model of rce harveser can be expressed as shown n Fgure 6. Major assumpons for hs schemac shown above are: 1. The cener of mass of frs and second fve blades s assumed o locae n plane-1 and plane-2, respecvely. 2. Plane-1 and plane-2 are parallel. 3. The source of vbraon only comes from he roaon of unbalanced mass. 4. Only varaon n angles a 15 and 90 of fan blade geomery s consdered. 5. The producon mus be conrolled under Cp = Fgure 7. Schemac of mass represenng each fan blade The force vbraon equaon of moon ha was developed by usng he frs, second and hrd assumpons can be expressed as follows: M X c X k X π mrωsn([( 1)( ) θ 5 2π mrωsn([( 6)( ) θ π ] ω) 2 π ] ω) 2 M m m (2) s (1) Where X() dsplacemen (m) M oal mass (kg) m 1 m 10 mass of blade no.1 o no 10 (kg) m s Ɵ mass of shaf (mg) me (s) devaon from perpendcular lne (rad) Fgure 6. Schemac of case sudy k c roang speed (rad/s) oal sprng consan (N/m) oal damplng consan (N.s/m) 3107

4 each fan blade group, he varaon n he fan blade s wegh does no have o generae unacceped vbraon. The Mone Carlo Smulaon s used for fndng he possbly of vbraon of fan blade un a dfferen condons. By employng he smulaon resuls, he lower lm and he upper lm of he fan blade s wegh for each group could be specfed. However, hs procedure can be used under a major creron ha he dsrbuon of wegh of fan blades mus be normal. EXPERIMENTAL SETUP The expermen began wh samplng he fan blades ha were produced n he producon lne. Then, he smulaon was carred ou followng he flow char shown n Fgure 8. In order o verfy he relably of he new procedure menoned n Fgure 8, he expermen was se as a schemac shown n Fgure 9. The maxmum amplude of vbraon (x,max) n a duraon of seconds was colleced by usng a vbraon analyzer model SKF Mcrolog CMXA 51-IS wh a sensor aached a he mddle ball bearng. Fgure 9. Schemac of esng apparaus RESULTS AND DISCUSSION Preparng for smulaon Fgure 8. Flow char of new procedure for reducng he effec of varaon n poson and dmenson of fan blade n rce harveser and combne harveser PROPOSE OF NEW PROCEDURE The new procedure for reducng he vbraon of fan blade n rce harveser and combne harveser was developed n hs research and presened n Fgure 8. The concep of hs procedure was ha he vbraon of he fan un can be sgnfcanly decreased f he sandard devaon of he fan blade s wegh s reduced. For conrollng he manufacurng cos, he produc (fan blade) groupng mehod nsead of makng precson fan blade s seleced. Afer fnsh fan blade producon, hence, he fan blades need o be grouped. For each assembly of fan un, all blades mus be aken from he same group. Addonally, for Snce he manufacurer produces approxmae 1000 fan blades for he 4-f model every year, a leas 278 fan blades mus be sampled. Ths number of sample was calculaed accordng o he sascal recommendaons [7-9]. In hs research, 278 fan blades were colleced. I was found ha he maxmum and mnmum wegh of hese sampled fan blades was kg and kg, respecvely. For checkng he ype of dsrbuon of fan blade wegh, all weghs of sampled fan blades were analyzed for her dsrbuon paerns by usng he Mcrosof Excel sofware. The analyss resuls showed ha he paerns of dsrbuon could be acceped as normal dsrbuon. The mean value was kg. The value of vbraon amplude ha he manufacurer can be acceped s 0.1 mm. Ths number was se as x v. However, here were some errors n he vbraon equaon of moon amplude (Eq. 1). Hence, he value of 2 was used as he safey facor. 3108

5 Smulaon resuls The smulaon process was carred ou accordng o he flow char shown n Fgure 8. The Mone Carlo smulaon was done by usng he Mcrosof Excel sofware. The example of usng he Mcrosof Excel sofware o do he Mone Carlo smulaon was nroduced by Jeges [10]. There were welve parameers ha mus be employed n he Mone Carlo smulaon. These were angle of 15±1 shown n Fgure 6, angle of 90±1 shown n Fgure 7, and wegh of 10 fan blades (m 1 m 10). The roaon speed was fxed a normal operaon, whch was 2,000 rpm. The smulaon resuls were shown n Table 1. In hs able, f he manufacurer needs o produce he fan uns ha have he maxmum vbraon amplude lower han 0.1 mm a C p = 1.00, hese fan blades mus be dvded no a leas four groups. For each fan un, all fan blades mus be aken from he same group. Table.1 Smulaon resuls from proposed procedure Group Max. Amplude of Vbraon (mm) Resul 1 G 1 : G 1 fal 2 G 1 : G 2 : G 1 : G 2 : G 3 : G 1 : G 2 : G 3 : G 4 : Noe: G 1, G 2 fal G 1, G 2 pass G 3 fal All group pass 1. Amplude of vbraon ha he manufacurer can be acceped s mm. 2. Amplude of vbraon n case of usng 2 as safey facor s mm. Table.2 Comparson beween smulaon and expermen Wegh of fan blades m 1 m 10: case G 3 of = , 0.443, 0.440, 0.438, 0.441, 0.442, 0.442, 0.445, 0.437, Max. vbraon amplude n duraon of s. (mm) New Procedure Expermen Verfcaon of new procedure for reducng he effec of varaon n poson and dmenson of fan blade n rce harveser and combne harveser In order o verfy he relably of he new procedure for reducng he effec of varaon n poson and dmenson of fan blade n rce harveser and combne harveser shown n Fgure 8, he esng apparaus was se as a schemac shown n Fgure 9. Ten fan blades from he same group (n case of = 4) were aken and hen bul as a fan un. The comparson of he maxmum vbraon amplude n duraon of s beween he calculaon followng he new procedure and he measurng resuls were shown n Table 2. I can be sad ha he new procedure ndcaed n Fgure 8 can be used n he producon lne for conrollng he vbraon of fan un. I should be noed ha he vbraon amplude of duraon of 0 10 s was no consdered because was he wang me for seady sae operaon of he fan blade sysem. CONCLUSION Accordng o he resuls n he resuls and dscusson menoned above, was found ha he new procedure for reducng he effec of varaon n poson and dmenson of fan blade n rce harveser and combne harveser, whch was nroduced n hs paper (Fgure 8), can conrol he vbraon of he fan blade no an accepable level. Whou he need of sac and dynamc balancng processes, hs procedure can herefore save he manufacurng me for assemblng he fan blade un sgnfcanly. ACKNOWLEDGEMENTS Auhors would lke o hank Kasesar Unversy for provdng a research gran. REFERENCES [1] Producs Dvson, 2000, TM102 Sac and Dynamc Balancng, TQ Educaon and Tranng Ld. [2] Grm, G. K., Hadler, J. W., and Mchell, B. J., 2014, The Basc of Balancng 202, Balance Technology Inc. [3] Camhaol, M. M., No Dae, Sac and Dynamc Balancng of Rgd Roors, Brüel & Kjaer. [4] Feese, T. D., and Grazer, P. E., 2004, Balance hs!: case hsores from dffcul balance jobs, The 33 rd Turbomachnery Symposum. [5] IRD Balancng, Balance Qualy Requremens of Rgd Roors: The Praccal Applcaon of ISO 1940/1, [6] ISO :1989., 1989, General Tolerances - Par 1: Tolerances for Lnear and Angular Dmensons whou Indvdual Tolerance Indcaons. 3109

6 [7] Cochran, W. G., 1977, Samplng Technque, hrd ed., John Wley & Son, USA. [8] Thompson, S. K., 2012, Samplng, hrd ed., John Wley & Son, USA. [9] Fuller, W. A., 2009, Samplng Sascs, John Wley & Son, USA. [10] Jeges, R., Mone Carlo smulaon n MS Excel, nformaon on hp:// 3110