The Research on the Auto Parts' Inbound Logistics Based on the Underground Logistics Mode

Transcription

1 ngang Zeng, Gaohu Yu, Yongq L, Zengshou Cu 63 The Research on the Auto Parts' Inbound Logstcs Based on the Underground Logstcs ode ngang Zeng, Gaohu Yu *, Yongq L, Zengshou Cu School of Busness Admnstraton South Chna Unversty of Technology, Guangzhou, Chna * EAIL: @qq.com Abstract: Because of the huge number of varety auto parts, nbound logstcs s consdered to be the most complcated and techncal operaton n the automoble logstcs system. In order to rase the logstcs level, the automoble company needs to strengthen the management of nbound logstcs. The purpose of ths paper s to fnd out the way n optmzng nbound logstcs modes through theoretcal and practcal method. In the begnnng, ths paper ntroduces the relatve concept about the nbound logstcs. Then t focuses on the underground logstcs whch s derved from the mode of drect delvery suppler to assembly automoble manufacturer. The paper llustrates the theoretcal research and operaton of domestc and nternatonal status of ths logstcs mode and rases the questons about the operaton of ths mode. After dong the research by mathematcal mode and makng an analyss of the current case about the underground logstcs mode, t summarzes the soluton for the nbound logstcs system. GT company case has shown that the logstcs cost usng the underground logstcs mode s much less. Keywords: Auto parts; nbound logstcs; underground logstcs; logstcs management I. Introducton The auto parts nbound logstcs s the actvtes of recevng, storage and provdng parts for manufacturng, ncludng the transportng, storage, vehcle dspatchng, contaners recyclng of the manufacturng materals. In other words, the auto parts nbound logstcs s the logstcs economc value ncreasng actvty to ensure the auto parts transported between the provders, the logstcs company and the manufacturer [1]. The underground logstcs system s an all-new transportaton and supply system for the sold goods usng the automated guded vehcle system (AGV) and Dual ode Trucks (DT) []. Snce the 9th n the th century, the research on the underground logstcs method to transport the goods s pad attenton by the western countres gradually, and s treated as one hgh-tech sector n the future. In Holland, the professonal underground logstcs system has been set up. In the past, Amsterdam, the captal of Netherlands, has the bggest flowers supply market n the world, and all the flowers are transported by the road transport systems. The traffc jam s a bg threat for those flowers that requres hgh tme demands. So, they buld the professonal underground logstcs system between the arport and the flower market, whch are under the ground mostly except for only some destnaton locatons, to shorten the tme and ncrease the safety attrbute [3]. Besdes Holland, Japan also developed ts underground logstcs systems wdely, n whch country t s treated as one of the hgh-tech sectors supported by the government n the next followng ten years. There are already the underground tunnels 1 km long and 16 warehouses n Tokyo. The underground system s expected to transport 36% goods n Tokyo and can ncrease the vehcles speed on ground by 3%. The total beneft can amount to 1. bllon yen per year, ncludng decreasng the vehcle s runnng cost, the runnng tme and ncdence rate and carbon doxde emssons [4]. In England, the ground logstcs has been used for a long tme. Snce 198, there s a mal transportng system runnng under the streets n London, connectng the 9 states between Paddngton and Whte Chapel, dealng wth more than 4 mllon posts [5]. And now there s a new auto underground logstcs transportaton system n London, n whch the nsde dameter s.74 meters, the maxmum capacty s 1 ton per truck and the maxmum speed s 6 km/h. England s the frst country to do research on the tunnel transportaton method and the best country to apply ths way [6]. In chna, the underground logstcs method sn t appled yet and the research n ths feld s very less, but n some ctes the studyng s gradually started. Some scholars proposed that the underground logstcs maybe approprate arport logstcs center, for example the Bejng s Captal Arport [7]. Frst, the arport logstcs center s fully-equpped publc utlty and nfrastructure, wth the functons of producng, transportng and dstrbuton. If the underground logstcs system s buld there, the cost can be lower than others for the already exsted land and facltes n the center. Second, the goods are very standard n the attrbutes of type, packng and delvery equpment, whch are very sutable for the underground logstcs way. Thrd, ths way can vod the unfavorable weather condton n Bejng. Though the project s not n process, relatve research has started now [8]. II. The Operaton Process of the Underground Logstcs ode The Fundamental Prncple of the Underground Logstcs ode The 4th Internatonal Conference on Operatons and Supply Chan anagement, Hongkong & Guangzhou, Jul.5 to Jul.31, 1

2 64 ngang Zeng, Gaohu Yu, Yongq L, Zengshou Cu In order to decrease the storage and shorten the procurement perod, some auto parts provders usually buld the automoble manufacturers near the car manufacturer, formng the suppler park. The auto parts are usually delvered n an order, whch s the assembly lne order. In order to ncrease the response speed, the tunnels are usually bult connectng the auto parts suppler and the automoble manufacturer drectly nstead of the publc road system. The auto parts sutable for ths knd of transportaton method are the very complcated professonal module, or the ones that can be quckly assembled. There are some dfferences between the underground logstcs method and the mlk run method: frst, the man feature of the underground logstcs mode s JIT, pckng up the auto parts accordng to the assembly lne order and delverng them just n tme to the rght place; second, the tunnels and the vehcles are specal desgned for the dfferent auto parts and the accessory facltes are also needs specal desgned. Thrd, the automoble manufacturer should send the assembly lne data to the provder n tme to ensure that all the data the provder have are very new. The underground logstcs mode s run lke the fgure I. Fgure I The Schematc Drawng of the Underground Logstcs ode The Implement Condtons of the Underground Logstcs ode The underground logstcs method s a very specal way, so ts applyng condtons are very strct, whch nvolve the transportaton route, delverng equpment, loadng platform and nformaton system. (1) The specal auto parts transportaton route The underground logstcs mode needs to be appled under the ground, usng the tunnel, and the tunnel should satsfy the specal vehcles runnng on the two-way road. The tunnels are usually used to connect the auto parts suppler and the automoble manufacturers, choosng the shortest way, so the factors about the dran, lghtng, geologcal structure and other factors. () The specal delverng equpment Because the specal attrbute of ths logstcs mode, the delverng equpments should be made specal to work flexbly. So, the small towng vehcles are sutable for ths mode. Besdes the towng vehcle, the traler also should be made specal to store and delver the auto parts to protect the goods and ncrease the loadng and unloadng speed. (3) The specal loadng platform At the provder locaton and the automoble manufacturer, specal loadng platforms are needed to load and unload the auto parts. For the automoble manufacturer, the specal loadng platform can be set up near the assembly lne to shorten the auto parts transportaton dstance. (4) The excellent nformaton system To acheve the purpose of transportng the manufacturng data, ncludng the assembly order data to the auto parts provder quckly and precsely, the powerful nformaton system s necessary and ndspensable. The Features of Auto Parts Underground Logstcs ode There are many features for the auto parts underground logstcs mode, whch make the mode n auto parts transportaton s very unque and dfferent. (1) Pckng up auto parts wth hgh frequency, low volume and JIT Because the underground logstcs can avod the traffc jam, bad weather condton and other thngs, the auto parts can be dstrbuted mmedately by the suppler when the automoble manufacturer s plan changed. Ths s a more optmzed mode than others, for whch the features are hgh frequency, low volume, non scheduled and quantfed. The assembly schedule may change and the provder should delver the goods as they ordered, and the underground logstcs can deal wth ths problem and satsfy the JIT requrement. () Pont to pont way transportaton The underground logstcs can delver the auto parts from the provder to the automoble manufacturer drectly, the pont to pont way. And the underground logstcs can also provde auto parts usng the several-for-one way and the trucks can pck up the auto parts n dfferent places. The auto parts provders usually are located no more than klometers from the automoble manufacturer, connectng wth the tunnels drectly, so the transportaton safety and effcency can be satsfed. (3) The strctly controlled runnng route The underground logstcs mode s based strctly on the runnng route schedule, controllng the drvng speed, drvng route and no stoppng. So the traffc capacty should be desgned more precsely, whch was the dffculty for ths logstcs mode. (4) Flexble producton control The underground logstcs are more sutable for the flexble producton, because the provders can response very quckly to the automoble manufacturer orders. The auto parts provders can stop the delverng mmedately to avod the bg amount of storage and they also can control the nventory level. (5) Transportaton rhythm accord wth the take tme The underground logstcs mode transportaton s n accordance wth the take tme to delver the auto parts to the automoble manufacturer accordng the order n tme. (6) Hgh effcency transportaton speed In the underground logstcs mode, the auto parts are delvered drectly to the automoble manufacturer s assembly lne, so the processes of storng n the warehouse, delverng the auto parts from the warehouse to the The 4th Internatonal Conference on Operatons and Supply Chan anagement, Hongkong & Guangzhou, Jul.5 to Jul.31, 1

3 ngang Zeng, Gaohu Yu, Yongq L, Zengshou Cu 65 assemblng lne are saved and the underground logstcs mode s more effcent. III. The Plannng ethod and odel for the Auto Parts Inbound Logstcs Based on the Underground Logstcs ode The Plannng Prncple for the Auto Parts Inbound Logstcs Based on the Underground Logstcs ode The constructon for the underground logstcs s very complcated, so the early plannng s necessary, especally the tunnel entrance. When selectng the tunnel entrance poston, we should follow those followng prncples. (1) Economc prncple The logstcs lnks nclude the tunnels at the automoble manufacturer and the supplers locaton, and the costs nclude the constructon cost the logstcs cost (the operatng cost). To save the costs, only one or two tunnels are bult between the automoble manufactures and auto parts suppler center. () The natural envronment accommodaton prncple On the tunnel ste selectng process, the factors of clmate condton, geologcal condton and geographc condton should be consdered very carefully. For example, the tunnel s ventlaton condton, mosture controllng, whether there are the slt seam or the loose sol seam, whether t can nfluence the buldngs on the ground and other thngs. (4) The strategc consderaton The ordnance of the underground logstcs system wth the road transportaton n the logstcs center should be consdered carefully, and the constructon plan should be global and long-term. (4) The dynamc prncple The constructon plan should consder the changes n the future more and should do more searches on the demand n the future. The Plannng odel of the Underground Logstcs The plannng for the underground logstcs system should consder more about the economc prncple, so the layout of the auto parts supplers besdes the automoble manufacturer s very mportant. The supplers center should lne wth the manufacturer rather than crclng around t. It can be shown n the fgure II. Fgure II The Layout of the Supplers Relatve to the anufacturer The tunnel connects the automoble manufacturer and the suppler center, and the tunnel entrance ste selectng n the supplers center s the man task. It s a sngle faclty locaton problem, whch can be solved wth the center of gravty method. The model can be descrbed as follows. There are n supplers as shown n fgure III. y (X1,Y1) (Xn,Yn) x Fgure III The Supplers Poston (1) The know condtons 1) The coordnate of each suppler s (X, Y ) ( = 1,,3,,n) ; ) The amount delvered from each auto parts suppler per day s V ( j=1,, 3,, n); 3) The transportaton rate n ths suppler center s R ; 4) The tunnel entrance s coordnate n the suppler center s (X,Y ); () Assumptons In order to smplfy the sngle faclty locaton problem, there are some assumptons: 1) The transportaton cost s proportonal to the dstance; ) The transportaton route s straght; 3) The constructon cost n dfferent stes s equal; 4) Ignore the transportaton changes n the future; 5) The tunnel entrance n the suppler center to other suppler s dstance s D. The formula s: D = k ( X X ) ( Y Y ) (1) In ths formula, k s the proportonal scales of the coordnate unte wth the real space dstance. (3) athematcal model The objectve functon of the model s mnmzng of the total cost,.e.: n TC = V R D () In ths formula, TC s the auto parts total delverng out amount transportaton cost of all the supplers per day; V s the delverng amount for suppler per day; R s the transportaton rate from the tunnel entrance of the supplers center to suppler I; D s the dstance from the tunnel entrance of the supplers center to suppler I; ake out the dervatve of the objectve functon and substtute the dstance formula, and then equate the coordnate of the tunnel entrance of the supplers center as follows: X = V R x / D V R / D (3) The 4th Internatonal Conference on Operatons and Supply Chan anagement, Hongkong & Guangzhou, Jul.5 to Jul.31, 1

4 66 ngang Zeng, Gaohu Yu, Yongq L, Zengshou Cu Y = V R y / D V R / D (4) The solvng steps of the center of gravty method 1) Determne the coordnate, delverng amount and transportaton rate of the supplers; ) akng out the prmary coordnate ( X, Y ) accordng to the formula (3) and formula (4). The dstance s supposed to be 1,.e., D =1; X = Y = V R x V R V R y V R 3) ake out the dstance D accordng to ( X, Y ), where the scale coeffcent k s not concerned. 4) Substtute the dstance D nto formula (3) and formula (4), and then make out the revsed coordnate (X, Y); 5) ake out the dstance D usng the revsed coordnate (X, Y); 6) Repeat the step 4) and step 5) untl the changes of (X, Y) are less than the desred error range; 7) ake out the total transportaton cost usng the acceptable coordnate. 8) Fx the fnal coordnate of the tunnel entrance n the supplers center based on the real space condton and other nfluencng factors. The passng ablty s the maxmum number of the vehcles passng through the tunnel s some place n a fxed tme perod lmted by the road condton and traffc control, whch s basc ndex for road plannng and managng, and the unt s pcu/h. The producton ablty of the automoble manufacturer can affect the frequency of the delverng tmes, so the tunnel s passng capacty can be nfluenced by the producton ablty. The tunnel s passng capacty model can be descrbed as follows: (1) Theoretcal model The headway dstance s the dstance between of the two cars heads, and the tunnel s passng capacty can be made out usng the headway dstance algorthm. Supposng the vehcles s runnng on the tunnel at a constant speed, y km/l one car by one car wth the mnmum vertcal dstance I, so the passng capacty s as follows: 1V 1V Np = = (7) L v v ' L + t l ( ) In ths formula, V s the drvng speed; L s the headway dstance (L= L + S); L s the car s length; S s the stoppng sght dstance whch ncludes the response dstance (4) (5) (6) v/3.6t, the brakng dstance S= v/54( ) and the v v ' headway dstance lˊ;.e. S = t l ; ( ) t s the drver s response tme, whch s usually 1. second; s the frcton coeffcent, whch s usually range from.3-.4; s the road slope; l ' s the dstance between the front car back and behnd car s head, whch s usually 5 m. () The passng capablty model of the tunnel n the real condton When testng the capacty model n the real condton, the theoretcal result s prepared wth the real condton result to check f the tunnel can satsfy the producton ablty of the automoble manufacturer. The known condtons can be shown as follows: the automobles producton number per day s ; the types of the auto parts delvered through the underground logstcs system s m; the take tme s t(s/veh); the drvng speed s v(s/km); the carryng capacty per transportaton car s q automobles auto parts; the dstance from automoble manufacturer to the supplers center s D; the unloadng tme n the manufacturer s t 1 ; the loadng tme at the supplers s t. The assumptons are shown as follows: the each car s carryng capacty s the same; each knd of auto parts are delvered by only one car; the assembly lne s work tme s 4 hours per day; there are n supplers n the supplers center and each suppler can provde x knds of auto parts (x=1,,, x); the road n the tunnel s two-way lanes. The passng capacty model of the tunnel n the real condton s descrbed as follows: The delverng perod of each truck for certan auto parts s T nx,.e. v D nx t t T nx = 1 (8) The trucks numbers of certan suppler for certan auto part s C nx,.e., T C nx = nx (9) qt The total number of the trucks s C,.e., C = C nx (1) The auto parts delvered to the assembly lne per hour are: = (11) 4 The trucks needed to transport the amount of auto parts are: Na = C (1) nx q Na s also can be treated as the tunnel s passng capacty,.e.: The 4th Internatonal Conference on Operatons and Supply Chan anagement, Hongkong & Guangzhou, Jul.5 to Jul.31, 1

5 ngang Zeng, Gaohu Yu, Yongq L, Zengshou Cu 67 Dnx t1 t Na = v (13) 4q qt Comparng the formula (7) and formula (13), f Np>Na, the passng capacty can satsfy the producton ablty. IV. The Example selectng s really a problem. The Soluton for the Example Use the underground logstcs mode to the GT Company, buldng the two tunnels between the automoble manufacturer and the supplers center to transport the auto parts, usng the specal vehcles wth two tralers. It s assumed that there are 1 supplers n the center as shown n the fgure IV. In ths part, the model buld n the former part s appled on a real case to check ts feasblty and advantage. The Background of the Example GT Company s an automoble manufacturer, for whch the desgned capacty s hundred cars per year n the frst stage and s 16 hundred cars per year n the second plannng stage. The auto parts supplers are dstrbuted at Guangdong, Tanjn and Shangha, among whch the supplers number n Guangdong s more than 9, consttutng 88% of the total number. The logstcs mode of supplers at Tanjn and Shangha s mlk run way, and 5% of all the supplers are located n the supplers center. In the supplers center, there are 14 supplers and 1 n them provde 97% of all the more than 1 knds of auto parts. The total volume of the auto parts needed per day s 4 3, and all the supplers are located no more than km from automoble manufacturer. It s seen that 44% of the entre auto parts provded by the supplers n the supplers center, so the logstcs mode Auto parts suspenson grder Ol tank Fgure IV The Supplers Poston for GT Company After the calculatng, the results are compared wth mlk run way method, whch s the present pattern for GT Company n the faclty and staff occupyng, project cost and transportaton cost perspectve. Table I and table II are the faclty and staff comparson of the underground logstcs mode and the ground logstcs method, from whch we can see that the latter method s better. Table I The Faclty and Staff Occupaton n Ground Logstcs Way ode suppler A B Demandng amount per day/ 3 Project number tractor forklft Tracton battery car carrages People 6 8 sum 9 sum 8 9 sum 168 Exhaust ppe Glasses gates C L Table II The Faclty and Staff Occupaton n Underground Logstcs ode The Project tractor Tracton battery People Auto parts suppler forklft carrage demand number number sum number sum number Suspenson A 1 1 Ol tank B 1 Exhaust 3 C glasses L 1 gate The project cost s compared n table III. The 4th Internatonal Conference on Operatons and Supply Chan anagement, Hongkong & Guangzhou, Jul.5 to Jul.31, 1

6 68 ngang Zeng, Gaohu Yu, Yongq L, Zengshou Cu Table III The Project Cost Comparson From table 3 we can see the underground logstcs mode can save about more than 15 thousand RB. The transportaton cost s related wth the transportaton dstance, so we can compare the transportaton dstance to compare the transportaton cost. The data s shown n table IV and table V. Table IV The Transportaton Dstance and Transportaton Tmes of Ground Logstcs ode model to calculate the tunnel s entrance coordnate and the passng capacty of the tunnel. Fnally, t appled the model to GT Company to check that the underground logstcs mode s superor. References Please contact the author to get the reference lsts. Table V The Transportaton Dstance and Tmes of Underground Logstcs ode start end GT Amount /day 3 Amount /car Delver tmes Dstance per car /day L.K K.K D 1.K B.1K C 1.9K A 1.8K /car E 1.1K F 1.7K 3 68 H 1.5K G.8K I 1.4K J 1.9K From the two tables above, t s shown that the transportaton dstance for the underground logstcs mode s 54 klometers and the transportaton dstance for the ground logstcs way s 916 klometers. In ths case, we can see that the underground logstcs mode s better than the ground logstcs way method for GT Company. V. The Concluson In ths paper, t ntroduces the relatve concept about the nbound logstcs and t focuses on the auto parts underground nbound logstcs mode. Then t bulds the The 4th Internatonal Conference on Operatons and Supply Chan anagement, Hongkong & Guangzhou, Jul.5 to Jul.31, 1