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Disruption Management for a Box Erecting Machine
Information Control Problems in Manufacturing Proceedigs the IFAC on Proceedigs of of the 15th 15th IFAC Symposium Symposium on Proceedigs of theOttawa, 15th IFAC Symposium on May 11-13, 2015. Canada Information Control Problems in Available online at www.sciencedirect.com Information Control Problems in Manufacturing Manufacturing Information Control Problems in Manufacturing May May 11-13, 11-13, 2015. 2015. Ottawa, Ottawa, Canada Canada May 11-13, 2015. Ottawa, Canada
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48-3 (2015) 1055–1060 DisruptionIFAC-PapersOnLine Management for a Box Erecting Machine Disruption Management for a Box Erecting Machine DisruptionWoo Management a Box Erecting Machine Ram Kim, Namfor Uook Kim, Dong Woo Son,
Woo Ram Ram Kim, Kim,Yoon NamSeok UookChang* Kim, Dong Dong Woo Woo Son, Son, Woo Nam Uook Kim, Woo Ram Kim,Yoon NamSeok Uook Kim, Dong Woo Son, Chang* Yoon Seok Chang* Yoon Seok Chang* Ubiquitous Technology Application Research Center, Ubiquitous Technology Application Research School of Air Transport & Logistics, Ubiquitous Technology Application Research Center, Center, Ubiquitous Technology Application Research Center, School of Transport & Korea Aerospace University, School of Air Air Transport & Logistics, Logistics, School of Air Transport Logistics, Korea Aerospace University, Goyang, Republic of&Korea Korea Aerospace University, Korea Aerospace University, Goyang, Republic of Korea (e-mail: [email protected], [email protected], [email protected], [email protected]) Goyang, Republic of Korea Goyang, Republic [email protected], of Korea (e-mail: [email protected], [email protected], [email protected]) (e-mail: [email protected], [email protected], [email protected]) *Corresponding [email protected], Author (e-mail: [email protected], [email protected], [email protected], [email protected]) *Corresponding Author *Corresponding Author *Corresponding Author system that transforms a folded paper Abstract: A box erecting machine is an automatic and mechanical Abstract: A box erecting machine is an automatic and mechanical system transforms aa folded into a three dimensional box in logistics industries. The transformed box that is used by workers who paper pack Abstract: A box erecting machine is an automatic and mechanical system that transforms folded paper Abstract: Adimensional box erectingbox machine is an Nowadays, automatic and mechanical system that transforms a folded paper into a three in logistics industries. The transformed box is used by workers who pack products then dispatched to customers. due to the rapid growth of E-commerce market and into a three dimensional box in logistics industries. The transformed box is used by workers who pack intogrowing a three dimensional box inbox logistics industries. Thetotransformed box is of usedtoby workers who pack products then dispatched to Nowadays, due market and the of product erecting technology moregrowth flexibility erect various sizes of products thenvariety dispatched to customers. customers. Nowadays, due requires to the the rapid rapid growth of E-commerce E-commerce market and products thenvariety dispatched to customers. Nowadays, to the rapid growth of E-commerce market and the growing product erecting technology more flexibility to various sizes box efficiently. Suchof issuedue ofrequires significant setup time for erecting machine. A the growing variety of requirement product box box brought erecting the technology requires more flexibility to erect erect various sizes of of the growing product box brought erecting technology requires more flexibility to erect various sizes of box efficiently. Such requirement the issue of setup erecting machine. A setup occurs variety when aofworker adjusts a machine change from the last boxtime typefor of the previous order to box efficiently. Such requirement brought the to issue of significant significant setup time for erecting machine. A box efficiently. Suchworker requirement the to issue of significant setup time for erecting machine. A setup occurs when aa machine from box the previous order the first box type next adjusts order brought and the setup a big disruption in operating setup occurs whenofaa the worker adjusts machine toischange change from the the last last box type type aof ofbox the erecting previousmachine. order to to setup occurs when a the worker adjusts a machine toischange from theoflast box erecting type aofbox the previousOne order to the first box type of next order and the setup a big disruption in operating erecting machine. In this paper, we presents two ways to mitigate the disruption a box machine. is to the first box type of the next order and the setup is a big disruption in operating a box erecting machine. the first box of process the next of order and the setup isthe a big disruption in operating atype box machine. In this we ways to disruption of erecting machine. One is automate thetype setup erecting machine we propose the new oferecting machine In this paper, paper, we presents presents two two the ways to mitigate mitigate the and disruption of aa box box erecting machine. Onewhich is to to In this paper, we presents two ways to mitigate the disruption of a box erecting machine. One is to automate the setup process of the erecting machine and we propose the new type of machine which automates the whole setup process. The other way is to sequence box erecting jobs considering the setup automate the setup process of the erecting machine and we propose the new type of machine which automate setup process of the erecting and we propose the new type of machine which automates the whole setup The way to time. It canthe reduce the setupprocess. time without anymachine costly automates the whole setup process. The other other way is isinvestment. to sequence sequence box box erecting erecting jobs jobs considering considering the the setup setup automates the whole setup process. The other way is to sequence box erecting jobs considering the setup time. It can reduce the setup time without any costly investment. time. It can reduce the setup time without any costly investment. © 2015, IFAC (International Federation Automatic Hosting automation by Elsevier Ltd. All rights reserved. time. It can reduce the setup time without anysequencing, costlyControl) investment. Keywords: box erecting machine, setup,ofjob disruption, Keywords: Keywords: box box erecting erecting machine, machine, setup, setup, job job sequencing, sequencing, disruption, disruption, automation automation of the industry, we are developing Keywords: box erecting machine, setup, job sequencing, disruption, and satisfy theautomation requirement 1. INTRODUCTION satisfy requirement of we are aand new type the of box erecting machine which is a flexible and satisfy the requirement of the the industry, industry, wecalled are developing developing 1. and satisfy the requirement oferect the industry, we are developing 1. INTRODUCTION INTRODUCTION new type of box box erecting machine which is is called flexible machine and canmachine various sizes ofaa flexible box in aa new type of erecting which called 1. INTRODUCTION A box erecting machine is an automatic and mechanical erecting a new type of box erecting machine which issizes calledofa flexible erecting machine and can erect various box of in efficient way through a research project, Development erecting machine and can erect various sizes of in A box erecting machine is an automatic and mechanical system that swiftly transforms a cardboard into a threeA box erecting machine is an automatic and mechanical erecting machine and can erect various sizes of box box in A box erecting machine is anprocess, automatic andinto mechanical efficient way through a research project, Development of Korean Unmanned Logistical Air Vehicle (KULAV) Based efficient way through a research project, Development of system that swiftly transforms a cardboard a threedimensional box. After erecting the transformed box system that swiftly transforms a cardboard into a three- efficient way through a research project, Development of system that swiftly transforms a cardboard into a threeKorean Unmanned Logistical Air Vehicle (KULAV) Based Tactical Logistics Convergence System funded by the dimensional box. After After erecting process, the transformed transformed box Korean Unmanned Logistical Air Vehicle (KULAV) Based is used to contain products that are supposed to be dispatched dimensional box. erecting process, the box Korean Unmanned Logistical Air Vehicle Based dimensional box. After erecting process, transformed box Tactical Convergence System funded by government of Republic of Korea. In this (KULAV) research Tactical Logistics Logistics Convergence System funded project, by the the is to products that to to customers in factories, or the distribution centres. is used used to contain contain productswarehouses, that are are supposed supposed to be be dispatched dispatched Tactical Logistics Convergence System funded by the is used contain products that are supposed to be dispatched of of In research the flexible box erecting machine various sizesproject, of box government of Republic Republic of Korea. Korea.erects In this this research project, to customers in or distribution centres. The boxtoerecting machinewarehouses, is especially under certain government to customers in factories, factories, warehouses, or useful distribution centres. government of Republic of Korea. In this research project, to customers in factories, warehouses, distributionpack centres. the box erecting machine sizes of will be used to pack variouserects kinds various of military supplies. the flexible flexible box erecting machine erects various sizes of box box The box machine is especially useful environment where workers to or consistently the which The box erecting erecting machine is have especially useful under under certain certain the flexible box erecting machine erects various sizes of box The box erecting machine is especially useful under certain which will be used to pack various kinds of military supplies. The packaged products are dispatched to operation areas by which will be used to pack various kinds of military supplies. environment where workers have to consistently pack the small amount of products and expedite them to customers environment where workers have to consistently pack the which will be used to pack various kinds of military supplies. environment where workers have tois consistently pack the unmanned The packaged products are dispatched to operation areas aerial vehicles (UAVs) which equip with special The packaged products are dispatched to operation areas by small amount of products and expedite them to customers located in various spots (e.g. It widely used in the small amount of products and expedite them to customers The packaged products are dispatched to operation areas by by small amount of products and expedite them to customers unmanned aerial vehicles (UAVs) which equip with special devices for grabbing various shapes of objects. This system unmanned aerial vehicles (UAVs) which equip with special located in various spots (e.g. It is widely used in the warehouse of online sales companies). As E-commerce and located in various spots (e.g. It is widely used in the unmanned aerial vehicles (UAVs) which equip with special located in various spots (e.g. It is widely used in the devices for grabbing various shapes of objects. This system will be useful when the operation areas are isolated by many for grabbing various shapes of objects. This system warehouse of sales As E-commerce and other industries that handle small products the needs warehouse of online online sales companies). companies). As expand, E-commerce and devices This system for various features, shapes of natural objects. disaster, warehouse online sales companies). As expand, E-commerce and devices will when the e.g.grabbing geographical the will be be useful useful when the operation operation areas areas are are isolated isolated by by many many other that handle small products the for theindustries box of erecting also expected to be increased. other industries that system handle are small products expand, the needs needs reasons, will be useful when the operation areas are isolated by many other industries that handle small products expand, the needs reasons, e.g. geographical features, natural disaster, destruction of roads, etc. The use of UAVs for logistics the for the box box erecting erecting system are also expected to (SKUs) be increased. increased. Furthermore, the number of are stock keeping units to be reasons, e.g. geographical features, natural disaster, the for the system also expected to be reasons, e.g. geographical features, natural the for the box erecting system are also expected to be increased. etc. The The use of of UAVs for logistics of roads, operations has suggested several times overdisaster, the past few destruction of been roads, etc. use UAVs for logistics Furthermore, the keeping units to handled is growing and of thestock customer demands are getting Furthermore, the number number of stock keeping units (SKUs) (SKUs) to be be destruction destruction of roads, etc. The use of UAVs for logistics Furthermore, number of stockSuch keeping units (SKUs) to be operations operations has been been suggested suggested several times over the the past past few (Jones, 2007). Recentlyseveral famous companies suchfew as has times over handled is and the demands getting diversified inthe those industries. handled is growing growing and the customer customercircumstance demands are arerequires getting years operations has been suggested several times over their the past few handled is growing and the customer demands are getting Google years (Jones, 2007). Recently famous companies such as & Amazon have started to introduce UAVs years (Jones, 2007). Recently famous companies such diversified in those industries. Such circumstance requires higher level of flexibility of erecting machine for the various diversified in those industries. Such circumstance requires years (Jones, 2007). Recently famous companies such as as diversified inof The those industries. Such circumstance requires Google & Amazon have started to introduce their UAVs specialized for logistics. The use of UAVs for transportation Google & Amazon have started to introduce their UAVs higher level flexibility of erecting machine for the various sizes of box. conventional machines are not efficient higher level of flexibility of erecting machine for the various Google & Amazon have started to introduce their UAVs higher level of The flexibility of erecting machine fornot the sizes various specialized for logistics. logistics. The to usedeal of UAVs UAVs for transportation transportation may be a good alternative with disruption on the for The use of for sizes box. conventional machines because setup to erectare various of specialized sizes of of they box. need The significant conventional machines are not efficient efficient specialized forinlogistics. The to usedeal of UAVs for transportation sizes of box. The conventional machines are not efficient may be a good alternative with disruption on that the supply chain some industries. But for this, it seems may be a good alternative to deal with disruption the because they need significant setup to erect various sizes of box. In general, setup includes obtaining tools, positioning because they need significant setup to erect various sizes of may be a good alternative to deal with disruption on on that the because they need significant setup to erect various sizes of supply chain in some industries. But for this, it seems more researches have to be conducted because the related box. setup tools, work in general, process material, return obtaining tooling, cleanup, setting the supply chain in some industries. But for this, it seems that box. In In general, setup includes includes obtaining tools, positioning positioning supply chain some industries. But forbecause this, it the seems that box. In setup includes obtaining tools, more researches researches have in to academic be conducted conducted related are notinaffluent fields. more have to be because the related work in general, process material, return tooling, cleanup, setting the studies required jigs andmaterial, fixtures, adjusting tools, and positioning inspecting work in process return tooling, cleanup, setting the more researches have to be conducted because the related work in process material, tooling, cleanup, setting the studies studies are are not not affluent affluent in in academic academic fields. fields. required jigs adjusting tools, and inspecting material et al., return 1999). Because setup does required (Allahverdi jigs and and fixtures, fixtures, adjusting tools, andusually inspecting studies are not affluent in academicerecting fields. machine in which This paper introduces a flexible required jigs and fixtures, adjusting tools, and inspecting material (Allahverdi et 1999). setup not include substantive for making productsdoes or material (Allahverdi et al., al.,operations 1999). Because Because setup usually usually does Thiswhole paperprocess introduces flexible erectingThe machine in which which the of setup is automated. automation can This paper introduces aa flexible erecting machine in material (Allahverdi al.,operations 1999). Because setup usually does not substantive for products or services, it may be et possible to simplify or omit the setup This paper introduces a from flexible erecting machine in which not include include substantive operations for making making products or exclude the whole whole process of setup setup is automated. automated. The automation can human labours setup andThe reduce setup time the process of is automation not include substantive operations for making products or services, be simplify or the operation the condition thatto manufacturing is the whole process of setup is automated. The automation can can services, it itonmay may be possible possible to the simplify or omit omit quality the setup setup exclude human human labours from job setup and reduce reduce setup time time significantly. Welabours also present sequencing algorithms that exclude from setup and setup services, it may be possible to simplify or omit the setup operation on that manufacturing quality is not degraded. So,condition it is desirable to reduce setup times which exclude human labours setup and reduce setup operation on the the condition that the the manufacturing quality is were significantly. Weto also present job sequencing algorithms that developed cut present thefrom setup time additionally. Sincetime the We also job sequencing algorithms that operation on the condition that the manufacturing quality is significantly. not degraded. So, it is desirable to reduce setup times which is one of major disruptions after breakdown in manufacturing significantly. We also present job sequencing algorithms that not degraded. So, it is desirable to reduce setup times which period were developed to cut the setup time additionally. Since the of the setup depends on the sizes of boxes to be were developed to cut the setup time additionally. Since not degraded. So, it is desirable to reduce setup times which is one of in and operations.after In breakdown this research, setup occurs were developed to cut the setup time additionally. Since the the is onewarehouse of major major disruptions disruptions after breakdown in manufacturing manufacturing period of the setup depends on the sizes of boxes to be erected, arranging the sequence of jobs to be processed has of the setup depends on the sizes of boxes to be is onewarehouse of major disruptions after breakdown manufacturing and operations. In research, setup when the box erecting machine changes ainbox type occurs to be period period ofarranging the for setup depends onoftime. the sizes of boxes to has be and warehouse operations. In this this research, setup occurs erected, the sequence jobs to be processed big potential reducing setup The job sequencing arranging the sequence of jobs to be processed has and operations. In research, occurs whenwarehouse the with box different erecting machine changes boxsetup type to be be erected, processed size. To this mitigate the disruption erected, arranging the sequence jobs The to bejob processed has when the box erecting machine changes aa setup box type to big potential potential for reducing reducing setupoftime. time. sequencing big setup The job sequencing when the box erecting machine changes a box type to be processed with with different different size. size. To To mitigate mitigate the the setup setup disruption disruption big potential for for reducing setup time. The job sequencing processed processed with different size. To mitigate the setup disruption
Copyright © 2015 IFAC 1105 2405-8963 © 2015, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. Copyright 2015 IFAC 1105 Copyright ©under 2015 responsibility IFAC 1105Control. Peer review© of International Federation of Automatic Copyright © 2015 IFAC 1105 10.1016/j.ifacol.2015.06.223
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algorithm can help the new erecting machine to expedite its work without any costly investment. Contrary to the importance of the box erecting machine in industry, the studies of box erecting technology are not abundant. Only few researchers studied box erecting machines or logistics systems that include box erecting devices. Yao et al. (2011) figured out an automatic robotic system to fold small cartons. They considered configurability as an important feature in their machine. Wang et al. (2011) designed a software for the control of bottle packaging system which has a box erecting device. Scheduling problems with setup have attracted many scholars for decades. Various solutions have been developed for the problems in diverse environments of industry (Allahverdi et al., 2008). It is considered that the job sequencing is useful to deal with the setup disruption of many cases.
boxes that are previously loaded on the feeding module and adjust the feeding module to load the new size of box.
Fig. 1. Conventional box erecting machine
The reminder of this paper is organized as follows. Section 2 describes the setup that causes disruption in the box erecting system and how the automation technology can treat the setup. Section 3 shows a job sequencing approach that is designed to reduce the setup time with heuristic and exact algorithms. The presented ideas are evaluated in section 4 with computer simulations. Lastly, the significance of this work and future research are emphasized in section 5. Fig. 2. Erecting process of erecting module 2. SETUP DISRUPTION AND FLEXIBLE ERECTING MACHINE In this section, we show the box erecting process in conventional erecting machine and describe the setup that causes a disruption of box erecting machine. Then, we introduce the flexible erecting machine and explain how the setup disruption can be mitigated by the new machine. 2.1 Erecting Process and Setup Disruption Fig. 1 shows a conventional box erecting machine. The machine mainly consists of two modules, a feeding module and an erecting module. The feeding module sends a folded box to the erecting module one by one. The erecting module consists of many components such as mast, injector, jaw plate, minor, major, taper, and etc. And these components systemically and sequentially transform the folded box to a three dimensional box (Fig. 2). After the erecting, the erecting module seals the bottom of the erected box. Finally, the prepared box is transported to a next place such as a packaging station. Although the whole erecting process is executed automatically without the intervention of human, the disruption occurs if a new size of box is needed because the erecting machine usually stores and erects only one size of box. In case that a different size of box has to be erected, the whole erecting system has to stop and workers have to do a series of setup operation for the new size of box. The setup of box erecting machine includes the following process. For a feeding module, workers unload the folded
The adjustment is also necessary for the erecting module. The erecting module has 7 parts (A ~ G) which have to be adjusted manually to the new size of box (Fig. 3). The amount of the adjustment depends on the differences between some measurements of a preceding box and the corresponding measurements of a consecutive box and they are depicted in Fig. 3. The adjustment of each part (A ~ G) is affected by the corresponding measurement in the figure. The setup (adjustment) is represented as a setup time in this work and the time can be formulated as follows. ST ij I A
*
FT A
*
L i L j I V A B
FT B
ID
*
IF
*
FT D
FT F
L i W
i
L j W
V D
H
i
W i H j W V F
W i W V B
j
IE
j
j
*
IG
FT E
*
*
IC
FT G
FT C
H i
W i W V C
W i 2
V E
j
H j
W
j 2
T i T j V G
(1)
where, the subscript i and j is a preceding box and a successive box respectively; STij is a setup time between the preceding box i and the successive box j; L, W, H and T are the length, width, height and thickness of box i or j; FT is the fixed setup time of the corresponding part (A ~ G); V is the moving velocity of the part; I is an indicator that has 0 or 1. The total setup time (STij) is the sum of the setup times of the 7 parts. It is assumed that the adjustment is conducted sequentially by one worker. The values in braces present the setup time of each part. I indicates whether the corresponding part has to be adjusted or not. If the part has to be adjusted, the value is 1, otherwise, the value is 0. The setup times of each part consist of fixed setup time (FT) that is not affected by measurements of boxes and unfixed setup time that
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depends on the measurements of boxes. The fixed time includes time for locking and unlocking a part. The unfixed setup time is defined by the length by which the each part has to be moved (the absolute values) and the moving velocity of each part (V). We did not count the moving time of workers in the formula assuming that the moving time is quite small. The setup for feeding module and erecting module takes significant time and labour, so, the conventional erecting machine is useful only when one type of box is erected.
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erecting module is being developed under the research project that is mentioned in the previous section.
Fig. 4. Feeding module of flexible erecting machine In contrast with the conventional erecting module, the 7 parts are adjusted simultaneously by electric devices. Even if the 7 parts of conventional machine can be adjusted almost simultaneously, it is not recommendable due to the safety and working efficiency of workers. Additionally, the speed of adjustments operated by the electric devices is faster than by a worker. It is considered that the new erecting module can save the large amount of time for setup. The setup time of the new erecting module can be calculated by (2) which is slightly modified from (1).
Fig. 3. Adjusting parts and corresponding measurements 2.2 Flexible Erecting Machine
ST ij MAX I A
To mitigate the disruption that is caused by the setup, we present a way to reduce the setup time with the automation technology that is applied to the flexible erecting machine. In the flexible erecting machine system, the whole erecting process can be conducted automatically even if there are many types of box to be erected alternately. What workers have to do is to make commands through computerized operating system. The new machine also consists of the feeding module and the erecting module but it has different shape and adjusting mechanism. In comparison with the conventional feeding module, the new feeding module of a flexible erecting machine stores various types of folded box and feeds a box of specific type to the erecting module in accordance with ejecting orders. Fig. 4 shows the actual design of the newly developed feeding module. It consists of multiple magazines, a conveyor, and a turning feeder. Magazines store folded boxes and eject the boxes to the conveyor one by one. Although each magazine has one size of box at one time, the magazines can be used for a number of sizes because it is designed to be adjusted flexibly to various sizes of box. The conveyor transports the ejected box from the magazine to the turning feeder. The turning feeder picks the transported box with its vacuum tentacles and rotate the vacuum tentacles to supply the box to the erecting module at opposite side. Another folded box can be transported and get ready near the turning feeder while the preceding box is supplied to the erecting module by the vacuum tentacles. This new module terminates the setup time of feeding module and makes it feasible to use one erecting machine for handling many types of box. In case of the erecting module, we designed that the adjustment was fully automatized. The fully automated
,
ID
,
IF
*
FT A
*
*
FT D
FT F
L i L j
,
V A
L i W
i
IB
*
L j W
V D
H
i
W i H j W V F
W i W V B
FT B
,
j
IE
,
j
*
IG
FT E
*
j
FT G
,
IC
*
H i
FT C
W i 2
W i W V C
V E
H j
j
W
j 2
T i T j V G
(2)
where, the operator MAX[ ] returns the maximum value among parameters separated by comma in square brackets, i.e. the longest time among the 7 adjusting times of each part is set as setup time. Other parameters have the same meaning as them of (1). 3. JOB SEQUENCING FOR MITIGATING SETUP DISRUPTION There has been a significant increase in interest in scheduling problems involving setup times or costs reflecting that the consideration of setup is important roles to make good scheduling decisions in various actual fields (Allahverdi et al., 2008). We suggests job sequencing methods to reduce the setup disruption caused by an erecting module. The setup time ((1) & (2)) is determined by the sizes of immediately processed box and a successive box to be processed, i.e. the sequence of consecutive jobs. The job sequencing has a high possibility for reducing the setup time because the sequencedependant setup is significantly affected by the sequence of jobs. Besides, the outstanding merit of the job sequencing is that the implementation needs little investment in comparison to the automation of machines. 3.1 Approach to Job Sequencing In this paper, we assume that box erecting machines operate in accordance with order lists which are a unit of job sequencing and consist of orders. Each order corresponds to a
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customer and consists of box types to be erected and the numbers of box which is corresponding to the required type. Customers may demand various types of box in one order. The type defines its own measurements of box. We also supposed that the jobs within an order are processed successively. Within an order, the same type of boxes is erected successively because it does not cause setup time. The job structure and the setup can be illustrated as Fig. 5. The colour of small boxes symbolizes the type of box and the number in the small boxes shows the number of boxes to be erected. The setup of erecting modules occurs in two cases. One case is when a type faces other type within an order (Inner setup). The other case is when a type faces other type on the border of consecutive orders (Outer setup). If the two types on border are identical, the outer setup does not occur. There are also two kinds of sequencing. One is to rearrange types of box within an order (type sequencing) and the other is to rearrange orders within an order list (order sequencing). The type sequencing often affects both inner setup and outer setup and the order sequencing affects only outer setup.
Reverse improvement. Reverse improvement executes type sequencing to improve outer setup time while B&B executes type sequencing for the improvement of inner setup time. Optimal solutions for inner setup time exist in a pair because the inner setup time between two types is not affected by which type is processed first, i.e. one type sequence within an order has the reversed arrangement which has the same quality. Even though the B&B can find the optimal solution, it does not determine which sequence is more proper in the perspective of the total setup time of an order list. To settle down the problem, we designed an improvement algorithm called Reverse improvement. An improvement algorithm systematically modifies the current solution and evaluates the modified solution. If it is better, the modification is made permanent and otherwise, the modification gets undone. The modification is continued until it is no longer possible to produce better solutions (Lee, 2006). We systemically reversed the type sequence as a modification and evaluated the resulting solutions with respect to the total setup time of the order list. The algorithm proceeds as Fig. 6. If there is an improvement of modification for an order, the preceding order is modified again as it has the possibility of an improvement again because the type sequence of its neighbour order has been changed. If there is no improvement, the next order is modified.
Fig. 5. Order structure and two kinds of setup. We consider that the sequencing problem is a variant of Traveling Salesman Problem (TSP) and applied algorithms that are useful to solve TSP. TSP have been usually adopted to manipulate scheduling problems that include sequencedependent setup because sequencing cities to be visited for the minimization of transportation cost can be easily represented as sequencing jobs to be processed for the minimization of setup cost (Sule, 1997; Allahverdi et al., 1999; Allahverdi et al., 2008). In type sequencing, each type of box and the sum of inner setup times correspond to each city and total transportation cost respectively. In order sequencing, each order and the sum of outer setup times also correspond to each city and total transportation cost respectively. 3.2 Algorithms for Sequencing Jobs To solve the sequencing problem which is represented as TSP, several algorithms were designed or applied. Branch-and-bound (B&B). For type sequencing, we adopted B&B to find the optimal sequence within an order. For exact algorithm like B&B, calculation time is a critical demerit for NP-complete or NP-hard problem such as TSP because the time required to solve the problem increases exponentially with respect to the problem size (Sule, 1997). We assumed that customers do not require more than 10 types of boxes for an order and found that the B&B requires only subtle time for TSP of up to 10 cities through some experiments.
Fig. 6. Flow chart of Reverse improvement Genetic Algorithm (GA). For order sequencing, we designed GAs which can find the feasible solutions of large sized problems within relatively short time assuming that there are many orders to be sequenced in an order list. Many variants of GA have been developed to deal with scheduling problems (Allahverdi et al., 2008). General GAs are not good at finding better solutions near the local optimal point, so local searching algorithms are added to supplement the weakness. GA including the local searching algorithm is called Memetic Algorithm (MA) (Mendes et al., 2002). Mendes et al. (2002) used MA to solve their one machine scheduling problem. They adopted 2 improvement algorithms as local search operators for their MA. We designed two GAs that have a different local search algorithm respectively. First GA uses 3Opt algorithm as local search algorithm with little modification. In 3-Opt, 3 links are chosen to be replaced for reducing cost. Since there are too many cases to be chosen (nC3, if n nodes have to be visited), we limited the number of the case for reducing calculation time, i.e. when the sum of cost of the three links is high, the case has possibility to be chosen and replaced. The modified 3-Opt executes the order sequencing. Second GA uses the Reverse improvement algorithm as a local search algorithm. In contrast with the modified 3-Opt, Reverse improvement is operated for type
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sequencing. So, type sequencing and order sequencing are conducted simultaneously through the second GA. Since type sequencing and order sequencing influence each other, one sequencing has to be conducted after the other sequence is determined. But it does not guarantee the optimal solution of the total setup time of an order list. So, the simultaneous operation of the two types of sequencing may rather have higher possibility for getting better solutions. The two GAs share the rest of operators. Roulette wheel selection, Modified Order Crossover (MOX), and swapping of the pair of genes was implemented as selection, crossover and mutation operator. The worst 67% of parental chromosomes was replaced with the best 67% of offspring chromosomes for replacement.
influence on the setup disruption. The fixed setup time and the adjusting velocity of each parts for the conventional erecting module were set at 2 or 3 s and 1 cm/s respectively and the values for the automated erecting module were set at 0.5 s and 2 cm/s. These values were set on the basis of existing machines and the opinions of engineers who are involved in the development. Table 1. Scenarios for simulation Attribute Automation
Value Manual Automated As is
4. COMPUTATIONAL EXPERIMENTS
Al 1
The effectiveness of the machine automation (flexible erecting machine) and the job sequencing was checked and evaluated. We checked the setup time of the conventional erecting module and the automated erecting module.
Al 2 Job Sequencing
4.1 Design of Simulation
Al 3
Al 4
The setup time was measured in accordance with 48 scenarios that are the combination of three attributes which are shown in Table 1. 6 cases for job sequencing and 4 types of order were prepared. In the first job sequencing case (As is), no sequencing method is applied. The second case (Al 1) has a simple method with which jobs are sequenced by the volume of box type. Other cases (Al 2 ~ 5) have a unique combination of job sequencing methods presented in section 3. For example, in Al 2, Reverse improvement is applied right after B&B is conducted. In Al 3, we fix a pair of box type on the border of each order, even if type sequencing methods (B&B and Reverse improvement) are applied, to recover the result of order sequencing made by GA with modified 3-Opt. The order type is defined by probabilities that each type is required to be erected by an order. The probabilities of each type were randomly defined with the triangular distribution as shown in Table 1. For example, all types of box are required with high probabilities by a customer (an order) and those probabilities are similar to each other in first case (Type 1), i.e. over 65.67 % and under 67.67 %. But in the last case (Type 4), all types have low probabilities to be required and all types have diverse probabilities each other according to the predefined distribution (i.e. Triangular[0, 0, 100]). The average of the distribution can indicate the average amount of box types to be required by a customer (an order) and the standard deviation of the distribution means the difference of popularity among types of box. The experiment was repeatedly conducted with 20 instances per each order type. The instance consists of 100 orders. We considered that there are 10 types of boxes that can be erected. The volume of the box type varies from 1,980 cm3 to 110,000 cm3. The measures of the types were drawn from Korean Industrial Standard and Korean post office (Korean Agency for Technology and Standard, 2011; Korea Post). The number of box to be erected was not considered because it does not
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Al 5 Type 1 Type 2 Order Type Type 3 Type 4
Description Conventional erecting module Automated erecting module of Flexible erecting machine Without job sequencing Type sequencing with the volume of box type 1st : B&B 2nd : Reverse improvement 1st : GA with modified 3-Opt 2nd : B&B 3rd : Reverse improvement 1st : B&B 2nd : Reverse improvement 3rd : GA with modified 3-Opt 1st : B&B 2nd : GA with Reverse improvement Triangular[65.67, 66.67, 67.67] Avg. : High / Stdev. : Low Triangular[0, 100, 100] Avg. : High / Stdev. : High Triangular[32.33, 33.33, 34.33] Avg. : Low / Stdev. : Low Triangular[0, 0, 100] Avg. : Low / Stdev. : High
4.2 Analysis of Result Fig. 7 shows the setup time of ejecting module for each order type ((a), (b), (c), and (d)). The value is the average of 20 experiments. For all scenarios, the automated erecting module showed significant improvements in setup time. The results corroborate that the almost 90 % of setup time could be saved by the automation technology. The results also testify that job sequencing can reduce the setup time substantially without costly investment in the automation of machine. As in the figure 7, AL 1 shows that even a simple sequencing can reduce the setup time. AL 2 demonstrates that it is possible to achieve a significant efficiency without the order sequencing. It implies that AL 2 is especially useful when orders have their own priorities under some strategies such as First In First Out (FIFO) rule. AL 3 shows worse results than AL 4. This implies that the type sequencing have to precede the order sequencing. For AL 3, we excluded a pair of box type from the border of each order for type sequencing which is executed after the order sequencing to prevent the result of the order sequencing from being affected by the type sequencing. We can suppose that the exclusion significantly contributed to the bad
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performance of AL 3. AL 4 and AL 5 achieved the best performance. These algorithms have saved about 50 ~ 60 % of setup time in comparison with the case of AS-IS. AL 5 surpassed the AL 4 slightly in terms of setup time, but it usually consumed more calculation time than AL 4 for making 300 generations. The result shows that order types do not have a meaningful influence on the improvement of setup time which is made by automation technology. But the order types affected the performance of job sequencing. The effectiveness of job sequencing diminishes as the average number of box type required by an order decrease ((a) and (b) vs. (c) and (d)). Especially AL 1 and AL 2 do not show good improvement in the case of order type 3 and 4. The difference of popularity among box types also affected the setup time. The results usually show that the cases of order type 2 and 4 have short setup time than the cases of order type 1 and 3 respectively. It is because the order type of high bias in popularity have the high possibility that orders require the same type of box. It implies that the outer setups can be reduced with high probability. 5. CONCLUSIONS In this paper, we proposed two ways to reduce setup time which causes disruption to the box erecting machine that is useful for the distribution of small products in logistics industry. We presented a new type of box erecting machine (flexible erecting machine) which can erect various types of boxes in efficient way with the aid of automation technology and some job sequencing algorithms which make it possible to increase performance of the machine with little investment. The proposed ways were demonstrated by computer simulation. The flexible erecting machine is expected to be used to cope with the complex and particular demands of customers in logistics area. And the proposed algorithms also may be applicable to many industrial situations that involve a sequence-dependant setup time. The research was conducted on the basis of existing machines and a new machine under development. Work using the actual machine will make it possible to elaborate our research.
ACKNOWLEDGEMENTS This work was supported by the C-ITRC Support Program (H0401-14-1021, Development of KULAV(Korean Unmanned Logistical Air Vehicle) Based Tactical Logistics Convergence System) funded by the Ministry of Science, ICT and Future Planning (MSIP, Republic of Korea). REFERENCES Allahverdi, A., Gupta, J.N., and Aldowaisan, T. (1999). A review of scheduling research involving setup considerations. Omega, 27 (2), 219-239. Allahverdi, A., Ng, C.T., Cheng, T.C.E., and Kovalyov, M.Y. (2008). A survey of scheduling problems with setup times or costs. European journal of operational research, 187 (3), 985-1032. Jones, E. (2007). New approaches for autonomous logistics aircraft and ground systems. In proceedings of 2007 institution of engineering and technology conference on autonomous systems, London, UK. Korea Post. Box standard for parcel service. Available at http://www.koreapost.go.kr/kpost/sub/subpage.jsp?contI d=010102010000 Accessed 14.10.31. Korean Agency for Technology and Standards. (2011). Standard dimension packaging container for home delivery. Korean industrial standard, KS T 1022. Lee, J.H. (2006). 2-opt algorithm approach to facility layout. In proceedings of the society of Korea industrial and system engineering spring conference. Mendes, A.S., Franca, P.M., and Moscato, P. (2002). Fitness landscapes for the total tardiness single machine scheduling problem. Neural network world, 12 (2), 165180. Sule, D.R. (1997), Industrial scheduling, pp. 10-11 and 44. PWS Publishing Company, Boston. Wang, Z., Zhang, Z.Y., Mei, J.P., Wang, L., Yu, D.X., and Zhang, L.A. (2011). Control system design of a case packing robot based on Simotion. In proceedings of 2011 international conference on electric information and control engineering (ICEICE), Wuhan, China. Yao, W., Cannella, F., and Dai, J.S. (2011). Automatic folding of cartons using a reconfigurable robotic system. Robotics and computer-integrated manufacturing, 27 (3), 604-613.
Fig. 7. Average setup time of ejecting module
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48-3 (2015) 1055–1060 DisruptionIFAC-PapersOnLine Management for a Box Erecting Machine Disruption Management for a Box Erecting Machine DisruptionWoo Management a Box Erecting Machine Ram Kim, Namfor Uook Kim, Dong Woo Son,
Woo Ram Ram Kim, Kim,Yoon NamSeok UookChang* Kim, Dong Dong Woo Woo Son, Son, Woo Nam Uook Kim, Woo Ram Kim,Yoon NamSeok Uook Kim, Dong Woo Son, Chang* Yoon Seok Chang* Yoon Seok Chang* Ubiquitous Technology Application Research Center, Ubiquitous Technology Application Research School of Air Transport & Logistics, Ubiquitous Technology Application Research Center, Center, Ubiquitous Technology Application Research Center, School of Transport & Korea Aerospace University, School of Air Air Transport & Logistics, Logistics, School of Air Transport Logistics, Korea Aerospace University, Goyang, Republic of&Korea Korea Aerospace University, Korea Aerospace University, Goyang, Republic of Korea (e-mail: [email protected], [email protected], [email protected], [email protected]) Goyang, Republic of Korea Goyang, Republic [email protected], of Korea (e-mail: [email protected], [email protected], [email protected]) (e-mail: [email protected], [email protected], [email protected]) *Corresponding [email protected], Author (e-mail: [email protected], [email protected], [email protected], [email protected]) *Corresponding Author *Corresponding Author *Corresponding Author system that transforms a folded paper Abstract: A box erecting machine is an automatic and mechanical Abstract: A box erecting machine is an automatic and mechanical system transforms aa folded into a three dimensional box in logistics industries. The transformed box that is used by workers who paper pack Abstract: A box erecting machine is an automatic and mechanical system that transforms folded paper Abstract: Adimensional box erectingbox machine is an Nowadays, automatic and mechanical system that transforms a folded paper into a three in logistics industries. The transformed box is used by workers who pack products then dispatched to customers. due to the rapid growth of E-commerce market and into a three dimensional box in logistics industries. The transformed box is used by workers who pack intogrowing a three dimensional box inbox logistics industries. Thetotransformed box is of usedtoby workers who pack products then dispatched to Nowadays, due market and the of product erecting technology moregrowth flexibility erect various sizes of products thenvariety dispatched to customers. customers. Nowadays, due requires to the the rapid rapid growth of E-commerce E-commerce market and products thenvariety dispatched to customers. Nowadays, to the rapid growth of E-commerce market and the growing product erecting technology more flexibility to various sizes box efficiently. Suchof issuedue ofrequires significant setup time for erecting machine. A the growing variety of requirement product box box brought erecting the technology requires more flexibility to erect erect various sizes of of the growing product box brought erecting technology requires more flexibility to erect various sizes of box efficiently. Such requirement the issue of setup erecting machine. A setup occurs variety when aofworker adjusts a machine change from the last boxtime typefor of the previous order to box efficiently. Such requirement brought the to issue of significant significant setup time for erecting machine. A box efficiently. Suchworker requirement the to issue of significant setup time for erecting machine. A setup occurs when aa machine from box the previous order the first box type next adjusts order brought and the setup a big disruption in operating setup occurs whenofaa the worker adjusts machine toischange change from the the last last box type type aof ofbox the erecting previousmachine. order to to setup occurs when a the worker adjusts a machine toischange from theoflast box erecting type aofbox the previousOne order to the first box type of next order and the setup a big disruption in operating erecting machine. In this paper, we presents two ways to mitigate the disruption a box machine. is to the first box type of the next order and the setup is a big disruption in operating a box erecting machine. the first box of process the next of order and the setup isthe a big disruption in operating atype box machine. In this we ways to disruption of erecting machine. One is automate thetype setup erecting machine we propose the new oferecting machine In this paper, paper, we presents presents two two the ways to mitigate mitigate the and disruption of aa box box erecting machine. Onewhich is to to In this paper, we presents two ways to mitigate the disruption of a box erecting machine. One is to automate the setup process of the erecting machine and we propose the new type of machine which automates the whole setup process. The other way is to sequence box erecting jobs considering the setup automate the setup process of the erecting machine and we propose the new type of machine which automate setup process of the erecting and we propose the new type of machine which automates the whole setup The way to time. It canthe reduce the setupprocess. time without anymachine costly automates the whole setup process. The other other way is isinvestment. to sequence sequence box box erecting erecting jobs jobs considering considering the the setup setup automates the whole setup process. The other way is to sequence box erecting jobs considering the setup time. It can reduce the setup time without any costly investment. time. It can reduce the setup time without any costly investment. © 2015, IFAC (International Federation Automatic Hosting automation by Elsevier Ltd. All rights reserved. time. It can reduce the setup time without anysequencing, costlyControl) investment. Keywords: box erecting machine, setup,ofjob disruption, Keywords: Keywords: box box erecting erecting machine, machine, setup, setup, job job sequencing, sequencing, disruption, disruption, automation automation of the industry, we are developing Keywords: box erecting machine, setup, job sequencing, disruption, and satisfy theautomation requirement 1. INTRODUCTION satisfy requirement of we are aand new type the of box erecting machine which is a flexible and satisfy the requirement of the the industry, industry, wecalled are developing developing 1. and satisfy the requirement oferect the industry, we are developing 1. INTRODUCTION INTRODUCTION new type of box box erecting machine which is is called flexible machine and canmachine various sizes ofaa flexible box in aa new type of erecting which called 1. INTRODUCTION A box erecting machine is an automatic and mechanical erecting a new type of box erecting machine which issizes calledofa flexible erecting machine and can erect various box of in efficient way through a research project, Development erecting machine and can erect various sizes of in A box erecting machine is an automatic and mechanical system that swiftly transforms a cardboard into a threeA box erecting machine is an automatic and mechanical erecting machine and can erect various sizes of box box in A box erecting machine is anprocess, automatic andinto mechanical efficient way through a research project, Development of Korean Unmanned Logistical Air Vehicle (KULAV) Based efficient way through a research project, Development of system that swiftly transforms a cardboard a threedimensional box. After erecting the transformed box system that swiftly transforms a cardboard into a three- efficient way through a research project, Development of system that swiftly transforms a cardboard into a threeKorean Unmanned Logistical Air Vehicle (KULAV) Based Tactical Logistics Convergence System funded by the dimensional box. After After erecting process, the transformed transformed box Korean Unmanned Logistical Air Vehicle (KULAV) Based is used to contain products that are supposed to be dispatched dimensional box. erecting process, the box Korean Unmanned Logistical Air Vehicle Based dimensional box. After erecting process, transformed box Tactical Convergence System funded by government of Republic of Korea. In this (KULAV) research Tactical Logistics Logistics Convergence System funded project, by the the is to products that to to customers in factories, or the distribution centres. is used used to contain contain productswarehouses, that are are supposed supposed to be be dispatched dispatched Tactical Logistics Convergence System funded by the is used contain products that are supposed to be dispatched of of In research the flexible box erecting machine various sizesproject, of box government of Republic Republic of Korea. Korea.erects In this this research project, to customers in or distribution centres. The boxtoerecting machinewarehouses, is especially under certain government to customers in factories, factories, warehouses, or useful distribution centres. government of Republic of Korea. In this research project, to customers in factories, warehouses, distributionpack centres. the box erecting machine sizes of will be used to pack variouserects kinds various of military supplies. the flexible flexible box erecting machine erects various sizes of box box The box machine is especially useful environment where workers to or consistently the which The box erecting erecting machine is have especially useful under under certain certain the flexible box erecting machine erects various sizes of box The box erecting machine is especially useful under certain which will be used to pack various kinds of military supplies. The packaged products are dispatched to operation areas by which will be used to pack various kinds of military supplies. environment where workers have to consistently pack the small amount of products and expedite them to customers environment where workers have to consistently pack the which will be used to pack various kinds of military supplies. environment where workers have tois consistently pack the unmanned The packaged products are dispatched to operation areas aerial vehicles (UAVs) which equip with special The packaged products are dispatched to operation areas by small amount of products and expedite them to customers located in various spots (e.g. It widely used in the small amount of products and expedite them to customers The packaged products are dispatched to operation areas by by small amount of products and expedite them to customers unmanned aerial vehicles (UAVs) which equip with special devices for grabbing various shapes of objects. This system unmanned aerial vehicles (UAVs) which equip with special located in various spots (e.g. It is widely used in the warehouse of online sales companies). As E-commerce and located in various spots (e.g. It is widely used in the unmanned aerial vehicles (UAVs) which equip with special located in various spots (e.g. It is widely used in the devices for grabbing various shapes of objects. This system will be useful when the operation areas are isolated by many for grabbing various shapes of objects. This system warehouse of sales As E-commerce and other industries that handle small products the needs warehouse of online online sales companies). companies). As expand, E-commerce and devices This system for various features, shapes of natural objects. disaster, warehouse online sales companies). As expand, E-commerce and devices will when the e.g.grabbing geographical the will be be useful useful when the operation operation areas areas are are isolated isolated by by many many other that handle small products the for theindustries box of erecting also expected to be increased. other industries that system handle are small products expand, the needs needs reasons, will be useful when the operation areas are isolated by many other industries that handle small products expand, the needs reasons, e.g. geographical features, natural disaster, destruction of roads, etc. The use of UAVs for logistics the for the box box erecting erecting system are also expected to (SKUs) be increased. increased. Furthermore, the number of are stock keeping units to be reasons, e.g. geographical features, natural disaster, the for the system also expected to be reasons, e.g. geographical features, natural the for the box erecting system are also expected to be increased. etc. The The use of of UAVs for logistics of roads, operations has suggested several times overdisaster, the past few destruction of been roads, etc. use UAVs for logistics Furthermore, the keeping units to handled is growing and of thestock customer demands are getting Furthermore, the number number of stock keeping units (SKUs) (SKUs) to be be destruction destruction of roads, etc. The use of UAVs for logistics Furthermore, number of stockSuch keeping units (SKUs) to be operations operations has been been suggested suggested several times over the the past past few (Jones, 2007). Recentlyseveral famous companies suchfew as has times over handled is and the demands getting diversified inthe those industries. handled is growing growing and the customer customercircumstance demands are arerequires getting years operations has been suggested several times over their the past few handled is growing and the customer demands are getting Google years (Jones, 2007). Recently famous companies such as & Amazon have started to introduce UAVs years (Jones, 2007). Recently famous companies such diversified in those industries. Such circumstance requires higher level of flexibility of erecting machine for the various diversified in those industries. Such circumstance requires years (Jones, 2007). Recently famous companies such as as diversified inof The those industries. Such circumstance requires Google & Amazon have started to introduce their UAVs specialized for logistics. The use of UAVs for transportation Google & Amazon have started to introduce their UAVs higher level flexibility of erecting machine for the various sizes of box. conventional machines are not efficient higher level of flexibility of erecting machine for the various Google & Amazon have started to introduce their UAVs higher level of The flexibility of erecting machine fornot the sizes various specialized for logistics. logistics. The to usedeal of UAVs UAVs for transportation transportation may be a good alternative with disruption on the for The use of for sizes box. conventional machines because setup to erectare various of specialized sizes of of they box. need The significant conventional machines are not efficient efficient specialized forinlogistics. The to usedeal of UAVs for transportation sizes of box. The conventional machines are not efficient may be a good alternative with disruption on that the supply chain some industries. But for this, it seems may be a good alternative to deal with disruption the because they need significant setup to erect various sizes of box. In general, setup includes obtaining tools, positioning because they need significant setup to erect various sizes of may be a good alternative to deal with disruption on on that the because they need significant setup to erect various sizes of supply chain in some industries. But for this, it seems more researches have to be conducted because the related box. setup tools, work in general, process material, return obtaining tooling, cleanup, setting the supply chain in some industries. But for this, it seems that box. In In general, setup includes includes obtaining tools, positioning positioning supply chain some industries. But forbecause this, it the seems that box. In setup includes obtaining tools, more researches researches have in to academic be conducted conducted related are notinaffluent fields. more have to be because the related work in general, process material, return tooling, cleanup, setting the studies required jigs andmaterial, fixtures, adjusting tools, and positioning inspecting work in process return tooling, cleanup, setting the more researches have to be conducted because the related work in process material, tooling, cleanup, setting the studies studies are are not not affluent affluent in in academic academic fields. fields. required jigs adjusting tools, and inspecting material et al., return 1999). Because setup does required (Allahverdi jigs and and fixtures, fixtures, adjusting tools, andusually inspecting studies are not affluent in academicerecting fields. machine in which This paper introduces a flexible required jigs and fixtures, adjusting tools, and inspecting material (Allahverdi et 1999). setup not include substantive for making productsdoes or material (Allahverdi et al., al.,operations 1999). Because Because setup usually usually does Thiswhole paperprocess introduces flexible erectingThe machine in which which the of setup is automated. automation can This paper introduces aa flexible erecting machine in material (Allahverdi al.,operations 1999). Because setup usually does not substantive for products or services, it may be et possible to simplify or omit the setup This paper introduces a from flexible erecting machine in which not include include substantive operations for making making products or exclude the whole whole process of setup setup is automated. automated. The automation can human labours setup andThe reduce setup time the process of is automation not include substantive operations for making products or services, be simplify or the operation the condition thatto manufacturing is the whole process of setup is automated. The automation can can services, it itonmay may be possible possible to the simplify or omit omit quality the setup setup exclude human human labours from job setup and reduce reduce setup time time significantly. Welabours also present sequencing algorithms that exclude from setup and setup services, it may be possible to simplify or omit the setup operation on that manufacturing quality is not degraded. So,condition it is desirable to reduce setup times which exclude human labours setup and reduce setup operation on the the condition that the the manufacturing quality is were significantly. Weto also present job sequencing algorithms that developed cut present thefrom setup time additionally. Sincetime the We also job sequencing algorithms that operation on the condition that the manufacturing quality is significantly. not degraded. So, it is desirable to reduce setup times which is one of major disruptions after breakdown in manufacturing significantly. We also present job sequencing algorithms that not degraded. So, it is desirable to reduce setup times which period were developed to cut the setup time additionally. Since the of the setup depends on the sizes of boxes to be were developed to cut the setup time additionally. Since not degraded. So, it is desirable to reduce setup times which is one of in and operations.after In breakdown this research, setup occurs were developed to cut the setup time additionally. Since the the is onewarehouse of major major disruptions disruptions after breakdown in manufacturing manufacturing period of the setup depends on the sizes of boxes to be erected, arranging the sequence of jobs to be processed has of the setup depends on the sizes of boxes to be is onewarehouse of major disruptions after breakdown manufacturing and operations. In research, setup when the box erecting machine changes ainbox type occurs to be period period ofarranging the for setup depends onoftime. the sizes of boxes to has be and warehouse operations. In this this research, setup occurs erected, the sequence jobs to be processed big potential reducing setup The job sequencing arranging the sequence of jobs to be processed has and operations. In research, occurs whenwarehouse the with box different erecting machine changes boxsetup type to be be erected, processed size. To this mitigate the disruption erected, arranging the sequence jobs The to bejob processed has when the box erecting machine changes aa setup box type to big potential potential for reducing reducing setupoftime. time. sequencing big setup The job sequencing when the box erecting machine changes a box type to be processed with with different different size. size. To To mitigate mitigate the the setup setup disruption disruption big potential for for reducing setup time. The job sequencing processed processed with different size. To mitigate the setup disruption
Copyright © 2015 IFAC 1105 2405-8963 © 2015, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. Copyright 2015 IFAC 1105 Copyright ©under 2015 responsibility IFAC 1105Control. Peer review© of International Federation of Automatic Copyright © 2015 IFAC 1105 10.1016/j.ifacol.2015.06.223
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algorithm can help the new erecting machine to expedite its work without any costly investment. Contrary to the importance of the box erecting machine in industry, the studies of box erecting technology are not abundant. Only few researchers studied box erecting machines or logistics systems that include box erecting devices. Yao et al. (2011) figured out an automatic robotic system to fold small cartons. They considered configurability as an important feature in their machine. Wang et al. (2011) designed a software for the control of bottle packaging system which has a box erecting device. Scheduling problems with setup have attracted many scholars for decades. Various solutions have been developed for the problems in diverse environments of industry (Allahverdi et al., 2008). It is considered that the job sequencing is useful to deal with the setup disruption of many cases.
boxes that are previously loaded on the feeding module and adjust the feeding module to load the new size of box.
Fig. 1. Conventional box erecting machine
The reminder of this paper is organized as follows. Section 2 describes the setup that causes disruption in the box erecting system and how the automation technology can treat the setup. Section 3 shows a job sequencing approach that is designed to reduce the setup time with heuristic and exact algorithms. The presented ideas are evaluated in section 4 with computer simulations. Lastly, the significance of this work and future research are emphasized in section 5. Fig. 2. Erecting process of erecting module 2. SETUP DISRUPTION AND FLEXIBLE ERECTING MACHINE In this section, we show the box erecting process in conventional erecting machine and describe the setup that causes a disruption of box erecting machine. Then, we introduce the flexible erecting machine and explain how the setup disruption can be mitigated by the new machine. 2.1 Erecting Process and Setup Disruption Fig. 1 shows a conventional box erecting machine. The machine mainly consists of two modules, a feeding module and an erecting module. The feeding module sends a folded box to the erecting module one by one. The erecting module consists of many components such as mast, injector, jaw plate, minor, major, taper, and etc. And these components systemically and sequentially transform the folded box to a three dimensional box (Fig. 2). After the erecting, the erecting module seals the bottom of the erected box. Finally, the prepared box is transported to a next place such as a packaging station. Although the whole erecting process is executed automatically without the intervention of human, the disruption occurs if a new size of box is needed because the erecting machine usually stores and erects only one size of box. In case that a different size of box has to be erected, the whole erecting system has to stop and workers have to do a series of setup operation for the new size of box. The setup of box erecting machine includes the following process. For a feeding module, workers unload the folded
The adjustment is also necessary for the erecting module. The erecting module has 7 parts (A ~ G) which have to be adjusted manually to the new size of box (Fig. 3). The amount of the adjustment depends on the differences between some measurements of a preceding box and the corresponding measurements of a consecutive box and they are depicted in Fig. 3. The adjustment of each part (A ~ G) is affected by the corresponding measurement in the figure. The setup (adjustment) is represented as a setup time in this work and the time can be formulated as follows. ST ij I A
*
FT A
*
L i L j I V A B
FT B
ID
*
IF
*
FT D
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i
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where, the subscript i and j is a preceding box and a successive box respectively; STij is a setup time between the preceding box i and the successive box j; L, W, H and T are the length, width, height and thickness of box i or j; FT is the fixed setup time of the corresponding part (A ~ G); V is the moving velocity of the part; I is an indicator that has 0 or 1. The total setup time (STij) is the sum of the setup times of the 7 parts. It is assumed that the adjustment is conducted sequentially by one worker. The values in braces present the setup time of each part. I indicates whether the corresponding part has to be adjusted or not. If the part has to be adjusted, the value is 1, otherwise, the value is 0. The setup times of each part consist of fixed setup time (FT) that is not affected by measurements of boxes and unfixed setup time that
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depends on the measurements of boxes. The fixed time includes time for locking and unlocking a part. The unfixed setup time is defined by the length by which the each part has to be moved (the absolute values) and the moving velocity of each part (V). We did not count the moving time of workers in the formula assuming that the moving time is quite small. The setup for feeding module and erecting module takes significant time and labour, so, the conventional erecting machine is useful only when one type of box is erected.
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erecting module is being developed under the research project that is mentioned in the previous section.
Fig. 4. Feeding module of flexible erecting machine In contrast with the conventional erecting module, the 7 parts are adjusted simultaneously by electric devices. Even if the 7 parts of conventional machine can be adjusted almost simultaneously, it is not recommendable due to the safety and working efficiency of workers. Additionally, the speed of adjustments operated by the electric devices is faster than by a worker. It is considered that the new erecting module can save the large amount of time for setup. The setup time of the new erecting module can be calculated by (2) which is slightly modified from (1).
Fig. 3. Adjusting parts and corresponding measurements 2.2 Flexible Erecting Machine
ST ij MAX I A
To mitigate the disruption that is caused by the setup, we present a way to reduce the setup time with the automation technology that is applied to the flexible erecting machine. In the flexible erecting machine system, the whole erecting process can be conducted automatically even if there are many types of box to be erected alternately. What workers have to do is to make commands through computerized operating system. The new machine also consists of the feeding module and the erecting module but it has different shape and adjusting mechanism. In comparison with the conventional feeding module, the new feeding module of a flexible erecting machine stores various types of folded box and feeds a box of specific type to the erecting module in accordance with ejecting orders. Fig. 4 shows the actual design of the newly developed feeding module. It consists of multiple magazines, a conveyor, and a turning feeder. Magazines store folded boxes and eject the boxes to the conveyor one by one. Although each magazine has one size of box at one time, the magazines can be used for a number of sizes because it is designed to be adjusted flexibly to various sizes of box. The conveyor transports the ejected box from the magazine to the turning feeder. The turning feeder picks the transported box with its vacuum tentacles and rotate the vacuum tentacles to supply the box to the erecting module at opposite side. Another folded box can be transported and get ready near the turning feeder while the preceding box is supplied to the erecting module by the vacuum tentacles. This new module terminates the setup time of feeding module and makes it feasible to use one erecting machine for handling many types of box. In case of the erecting module, we designed that the adjustment was fully automatized. The fully automated
,
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T i T j V G
(2)
where, the operator MAX[ ] returns the maximum value among parameters separated by comma in square brackets, i.e. the longest time among the 7 adjusting times of each part is set as setup time. Other parameters have the same meaning as them of (1). 3. JOB SEQUENCING FOR MITIGATING SETUP DISRUPTION There has been a significant increase in interest in scheduling problems involving setup times or costs reflecting that the consideration of setup is important roles to make good scheduling decisions in various actual fields (Allahverdi et al., 2008). We suggests job sequencing methods to reduce the setup disruption caused by an erecting module. The setup time ((1) & (2)) is determined by the sizes of immediately processed box and a successive box to be processed, i.e. the sequence of consecutive jobs. The job sequencing has a high possibility for reducing the setup time because the sequencedependant setup is significantly affected by the sequence of jobs. Besides, the outstanding merit of the job sequencing is that the implementation needs little investment in comparison to the automation of machines. 3.1 Approach to Job Sequencing In this paper, we assume that box erecting machines operate in accordance with order lists which are a unit of job sequencing and consist of orders. Each order corresponds to a
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customer and consists of box types to be erected and the numbers of box which is corresponding to the required type. Customers may demand various types of box in one order. The type defines its own measurements of box. We also supposed that the jobs within an order are processed successively. Within an order, the same type of boxes is erected successively because it does not cause setup time. The job structure and the setup can be illustrated as Fig. 5. The colour of small boxes symbolizes the type of box and the number in the small boxes shows the number of boxes to be erected. The setup of erecting modules occurs in two cases. One case is when a type faces other type within an order (Inner setup). The other case is when a type faces other type on the border of consecutive orders (Outer setup). If the two types on border are identical, the outer setup does not occur. There are also two kinds of sequencing. One is to rearrange types of box within an order (type sequencing) and the other is to rearrange orders within an order list (order sequencing). The type sequencing often affects both inner setup and outer setup and the order sequencing affects only outer setup.
Reverse improvement. Reverse improvement executes type sequencing to improve outer setup time while B&B executes type sequencing for the improvement of inner setup time. Optimal solutions for inner setup time exist in a pair because the inner setup time between two types is not affected by which type is processed first, i.e. one type sequence within an order has the reversed arrangement which has the same quality. Even though the B&B can find the optimal solution, it does not determine which sequence is more proper in the perspective of the total setup time of an order list. To settle down the problem, we designed an improvement algorithm called Reverse improvement. An improvement algorithm systematically modifies the current solution and evaluates the modified solution. If it is better, the modification is made permanent and otherwise, the modification gets undone. The modification is continued until it is no longer possible to produce better solutions (Lee, 2006). We systemically reversed the type sequence as a modification and evaluated the resulting solutions with respect to the total setup time of the order list. The algorithm proceeds as Fig. 6. If there is an improvement of modification for an order, the preceding order is modified again as it has the possibility of an improvement again because the type sequence of its neighbour order has been changed. If there is no improvement, the next order is modified.
Fig. 5. Order structure and two kinds of setup. We consider that the sequencing problem is a variant of Traveling Salesman Problem (TSP) and applied algorithms that are useful to solve TSP. TSP have been usually adopted to manipulate scheduling problems that include sequencedependent setup because sequencing cities to be visited for the minimization of transportation cost can be easily represented as sequencing jobs to be processed for the minimization of setup cost (Sule, 1997; Allahverdi et al., 1999; Allahverdi et al., 2008). In type sequencing, each type of box and the sum of inner setup times correspond to each city and total transportation cost respectively. In order sequencing, each order and the sum of outer setup times also correspond to each city and total transportation cost respectively. 3.2 Algorithms for Sequencing Jobs To solve the sequencing problem which is represented as TSP, several algorithms were designed or applied. Branch-and-bound (B&B). For type sequencing, we adopted B&B to find the optimal sequence within an order. For exact algorithm like B&B, calculation time is a critical demerit for NP-complete or NP-hard problem such as TSP because the time required to solve the problem increases exponentially with respect to the problem size (Sule, 1997). We assumed that customers do not require more than 10 types of boxes for an order and found that the B&B requires only subtle time for TSP of up to 10 cities through some experiments.
Fig. 6. Flow chart of Reverse improvement Genetic Algorithm (GA). For order sequencing, we designed GAs which can find the feasible solutions of large sized problems within relatively short time assuming that there are many orders to be sequenced in an order list. Many variants of GA have been developed to deal with scheduling problems (Allahverdi et al., 2008). General GAs are not good at finding better solutions near the local optimal point, so local searching algorithms are added to supplement the weakness. GA including the local searching algorithm is called Memetic Algorithm (MA) (Mendes et al., 2002). Mendes et al. (2002) used MA to solve their one machine scheduling problem. They adopted 2 improvement algorithms as local search operators for their MA. We designed two GAs that have a different local search algorithm respectively. First GA uses 3Opt algorithm as local search algorithm with little modification. In 3-Opt, 3 links are chosen to be replaced for reducing cost. Since there are too many cases to be chosen (nC3, if n nodes have to be visited), we limited the number of the case for reducing calculation time, i.e. when the sum of cost of the three links is high, the case has possibility to be chosen and replaced. The modified 3-Opt executes the order sequencing. Second GA uses the Reverse improvement algorithm as a local search algorithm. In contrast with the modified 3-Opt, Reverse improvement is operated for type
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sequencing. So, type sequencing and order sequencing are conducted simultaneously through the second GA. Since type sequencing and order sequencing influence each other, one sequencing has to be conducted after the other sequence is determined. But it does not guarantee the optimal solution of the total setup time of an order list. So, the simultaneous operation of the two types of sequencing may rather have higher possibility for getting better solutions. The two GAs share the rest of operators. Roulette wheel selection, Modified Order Crossover (MOX), and swapping of the pair of genes was implemented as selection, crossover and mutation operator. The worst 67% of parental chromosomes was replaced with the best 67% of offspring chromosomes for replacement.
influence on the setup disruption. The fixed setup time and the adjusting velocity of each parts for the conventional erecting module were set at 2 or 3 s and 1 cm/s respectively and the values for the automated erecting module were set at 0.5 s and 2 cm/s. These values were set on the basis of existing machines and the opinions of engineers who are involved in the development. Table 1. Scenarios for simulation Attribute Automation
Value Manual Automated As is
4. COMPUTATIONAL EXPERIMENTS
Al 1
The effectiveness of the machine automation (flexible erecting machine) and the job sequencing was checked and evaluated. We checked the setup time of the conventional erecting module and the automated erecting module.
Al 2 Job Sequencing
4.1 Design of Simulation
Al 3
Al 4
The setup time was measured in accordance with 48 scenarios that are the combination of three attributes which are shown in Table 1. 6 cases for job sequencing and 4 types of order were prepared. In the first job sequencing case (As is), no sequencing method is applied. The second case (Al 1) has a simple method with which jobs are sequenced by the volume of box type. Other cases (Al 2 ~ 5) have a unique combination of job sequencing methods presented in section 3. For example, in Al 2, Reverse improvement is applied right after B&B is conducted. In Al 3, we fix a pair of box type on the border of each order, even if type sequencing methods (B&B and Reverse improvement) are applied, to recover the result of order sequencing made by GA with modified 3-Opt. The order type is defined by probabilities that each type is required to be erected by an order. The probabilities of each type were randomly defined with the triangular distribution as shown in Table 1. For example, all types of box are required with high probabilities by a customer (an order) and those probabilities are similar to each other in first case (Type 1), i.e. over 65.67 % and under 67.67 %. But in the last case (Type 4), all types have low probabilities to be required and all types have diverse probabilities each other according to the predefined distribution (i.e. Triangular[0, 0, 100]). The average of the distribution can indicate the average amount of box types to be required by a customer (an order) and the standard deviation of the distribution means the difference of popularity among types of box. The experiment was repeatedly conducted with 20 instances per each order type. The instance consists of 100 orders. We considered that there are 10 types of boxes that can be erected. The volume of the box type varies from 1,980 cm3 to 110,000 cm3. The measures of the types were drawn from Korean Industrial Standard and Korean post office (Korean Agency for Technology and Standard, 2011; Korea Post). The number of box to be erected was not considered because it does not
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Al 5 Type 1 Type 2 Order Type Type 3 Type 4
Description Conventional erecting module Automated erecting module of Flexible erecting machine Without job sequencing Type sequencing with the volume of box type 1st : B&B 2nd : Reverse improvement 1st : GA with modified 3-Opt 2nd : B&B 3rd : Reverse improvement 1st : B&B 2nd : Reverse improvement 3rd : GA with modified 3-Opt 1st : B&B 2nd : GA with Reverse improvement Triangular[65.67, 66.67, 67.67] Avg. : High / Stdev. : Low Triangular[0, 100, 100] Avg. : High / Stdev. : High Triangular[32.33, 33.33, 34.33] Avg. : Low / Stdev. : Low Triangular[0, 0, 100] Avg. : Low / Stdev. : High
4.2 Analysis of Result Fig. 7 shows the setup time of ejecting module for each order type ((a), (b), (c), and (d)). The value is the average of 20 experiments. For all scenarios, the automated erecting module showed significant improvements in setup time. The results corroborate that the almost 90 % of setup time could be saved by the automation technology. The results also testify that job sequencing can reduce the setup time substantially without costly investment in the automation of machine. As in the figure 7, AL 1 shows that even a simple sequencing can reduce the setup time. AL 2 demonstrates that it is possible to achieve a significant efficiency without the order sequencing. It implies that AL 2 is especially useful when orders have their own priorities under some strategies such as First In First Out (FIFO) rule. AL 3 shows worse results than AL 4. This implies that the type sequencing have to precede the order sequencing. For AL 3, we excluded a pair of box type from the border of each order for type sequencing which is executed after the order sequencing to prevent the result of the order sequencing from being affected by the type sequencing. We can suppose that the exclusion significantly contributed to the bad
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performance of AL 3. AL 4 and AL 5 achieved the best performance. These algorithms have saved about 50 ~ 60 % of setup time in comparison with the case of AS-IS. AL 5 surpassed the AL 4 slightly in terms of setup time, but it usually consumed more calculation time than AL 4 for making 300 generations. The result shows that order types do not have a meaningful influence on the improvement of setup time which is made by automation technology. But the order types affected the performance of job sequencing. The effectiveness of job sequencing diminishes as the average number of box type required by an order decrease ((a) and (b) vs. (c) and (d)). Especially AL 1 and AL 2 do not show good improvement in the case of order type 3 and 4. The difference of popularity among box types also affected the setup time. The results usually show that the cases of order type 2 and 4 have short setup time than the cases of order type 1 and 3 respectively. It is because the order type of high bias in popularity have the high possibility that orders require the same type of box. It implies that the outer setups can be reduced with high probability. 5. CONCLUSIONS In this paper, we proposed two ways to reduce setup time which causes disruption to the box erecting machine that is useful for the distribution of small products in logistics industry. We presented a new type of box erecting machine (flexible erecting machine) which can erect various types of boxes in efficient way with the aid of automation technology and some job sequencing algorithms which make it possible to increase performance of the machine with little investment. The proposed ways were demonstrated by computer simulation. The flexible erecting machine is expected to be used to cope with the complex and particular demands of customers in logistics area. And the proposed algorithms also may be applicable to many industrial situations that involve a sequence-dependant setup time. The research was conducted on the basis of existing machines and a new machine under development. Work using the actual machine will make it possible to elaborate our research.
ACKNOWLEDGEMENTS This work was supported by the C-ITRC Support Program (H0401-14-1021, Development of KULAV(Korean Unmanned Logistical Air Vehicle) Based Tactical Logistics Convergence System) funded by the Ministry of Science, ICT and Future Planning (MSIP, Republic of Korea). REFERENCES Allahverdi, A., Gupta, J.N., and Aldowaisan, T. (1999). A review of scheduling research involving setup considerations. Omega, 27 (2), 219-239. Allahverdi, A., Ng, C.T., Cheng, T.C.E., and Kovalyov, M.Y. (2008). A survey of scheduling problems with setup times or costs. European journal of operational research, 187 (3), 985-1032. Jones, E. (2007). New approaches for autonomous logistics aircraft and ground systems. In proceedings of 2007 institution of engineering and technology conference on autonomous systems, London, UK. Korea Post. Box standard for parcel service. Available at http://www.koreapost.go.kr/kpost/sub/subpage.jsp?contI d=010102010000 Accessed 14.10.31. Korean Agency for Technology and Standards. (2011). Standard dimension packaging container for home delivery. Korean industrial standard, KS T 1022. Lee, J.H. (2006). 2-opt algorithm approach to facility layout. In proceedings of the society of Korea industrial and system engineering spring conference. Mendes, A.S., Franca, P.M., and Moscato, P. (2002). Fitness landscapes for the total tardiness single machine scheduling problem. Neural network world, 12 (2), 165180. Sule, D.R. (1997), Industrial scheduling, pp. 10-11 and 44. PWS Publishing Company, Boston. Wang, Z., Zhang, Z.Y., Mei, J.P., Wang, L., Yu, D.X., and Zhang, L.A. (2011). Control system design of a case packing robot based on Simotion. In proceedings of 2011 international conference on electric information and control engineering (ICEICE), Wuhan, China. Yao, W., Cannella, F., and Dai, J.S. (2011). Automatic folding of cartons using a reconfigurable robotic system. Robotics and computer-integrated manufacturing, 27 (3), 604-613.
Fig. 7. Average setup time of ejecting module
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