Renovation of the cutting stock process Erjavec, Jure; Gradišar, Miro; Trkman, Peter
International journal of production research,
07/2009, Volume:
47, Issue:
14
Journal Article
Peer reviewed
Open access
In this paper a new approach to the cutting stock (CS) problem as one of the activities in the CS process is proposed. A thorough critical review of the literature is conducted in order to identify ...the main limitations of the current state of research. The main finding is that the CS problem is treated too narrowly and that the connection of the CS process with other processes in a company, along with a better transfer of information, should be studied further. The paper presents a methodology for evaluating CS process renovation benefits. A process flowchart technique is used to compare as-was and as-is states, and simulations are conducted to provide an estimate of the benefits and to compare the costs of trim loss with other production costs. A case study of a company involved in non-ferrous metal and iron retail activities is used to analyse the effects of renovation of the whole CS process, which led to a considerable reduction in cutting costs and lead times. A decrease in the variability of the CS process lead time is also noted, which can lead to a more standardised fulfilment of customers' orders. The measurement and reduction of costs can improve the competitiveness of companies that undertake cutting or similar (e.g. packing) operations in production.
V članku je predstavljena metoda za reševanje problema enodimenzionalnega razreza z uporabnimi ostanki (1DCSPUL; angl. One-dimensional Cutting Stock Problem with Usable Leftovers), kjer se lahko ...ostanki trenutnega naročila uporabijo v prihodnosti, če so daljši ali enaki meji t. Krajši ostanki predstavljajo izgubo. Metoda obravnava problem določanja t. Pri nižjem t se na zalogi proizvede večje število uporabnih ostankov (UL; angl. Usable Leftovers), izguba materiala pri prihodnjih naročilih pa se posledično poveča. Predlagana metoda TOP-ECOLA je sestavljena iz dveh algoritmov; TOP in ECOLA. TOP izračuna optimalen t in optimalno število UL na zalogi. ECOLA minimizira izgubo materiala in ohranja optimalno raven UL. Metoda je preizkušena z uporabo računalniških simulacij, kjer so UL prejšnjih naročil uporabljeni v naslednjem naročilu, namesto da bi bili ustvarjeni naključno. Dobljeni rezultati kažejo, da TOP-ECOLA zmanjšuje izgubo materiala pri zaporednih naročilih in preprečuje nenadzorovano rast UL na zalogi.
The paper deals with the general one-dimensional cutting stock problem (G1D-CSP), where optimization is not limited to a single order. Stock cutting is treated as a permanent business process in a ...company in which consecutive order sets need to be fulfilled either for production needs or for its customers. Exact demand for future orders is not known in advance. The unutilized and partly utilized stock lengths left after fulfilling current order sets are stored and used later. The goal is the reduction of trim loss and costs over a broader time-span. A new approach is suggested where previously developed method for G1D-CSP is modified. Several practical examples of the cutting process for several consecutive order sets are presented. An extension to a currently used typology for cutting stock problems is proposed.
The article examines the Sequential Heuristic Procedure (SHP) for optimising one-dimensional stock cutting when all stock lengths are different. In order to solve a bicriterial multidimensional ...knapsack problem with side constraints a lexicographic approach is applied. An
item-oriented solution was found through a combination of approximations and heuristics that minimize the influence of
ending conditions leading to almost optimal solutions. The computer program CUT was developed, based on the proposed algorithm. Two sample problems are presented and solved. A statistical analysis of parameters that affect material utilisation was also made.
The paper deals with the problem of evaluating and comparing different one-dimensional stock cutting algorithms regarding trim loss. Different types of problems are identified. An evaluation method ...is developed which enables a comparison of solutions of all types of problems. A practical example of this methods implementation is presented.
There are many algorithms and methods for one-dimensional stock cutting with different factors that need to be taken into account. Therefore a general comparison between them is very difficult if not impossible. However, if we assume that trim loss is the most important factor common to different methods, we can overcome this problem by limiting the comparison to trim loss. In different cutting stock problems and in different approaches to them trim loss is defined differently. For the comparison of different solutions to be possible, we need to find a common definition to the trim loss. Such a general definition is introduced by the General One-Dimensional Cutting Stock Problem type (G1D-CSP). In this paper, a problem generator algorithm
PGEN for G1D-CSP is presented and the method for evaluation and comparison of different one-dimensional cutting stock algorithms is proposed.
Purpose - Enterprise resource planning (ERP) systems have been implemented in most organizations for a few years. ERP solutions go through three phases of lifecycle: selection, implementation and ...operation phase; the operation phase consists of the stabilization stage and the routine stage. To improve the efficiency and effectiveness of ERP system use in the operation phase, organizations need to research the factors that have impact on users' satisfaction. A literature shows that few published studies have examined users' adoption of ERP systems through a technological acceptance model (TAM) or examined external factors that have influence the intention to use an ERP system, or ERP use in the stabilization stage. The purpose of this paper is to expose and research external factors which have influence on ERP users in the operation phase of ERP lifecycle and to investigate the impact of those factors on ERP system use.Design methodology approach - The TAM proposed by Davis has been the most widely-used model for researching user acceptance and usage of information technology information systems. Despite the existence of several additions to TAM connected with ERP use, the authors aim to make further contribution in the area of external factors. Within this context the present research is focused on the mature use of ERP system (more than one year of ERP use in an organization). A limited number of external factors mentioned in already published papers connected with TAM regarding ERP use has also been extended. The authors have researched the effect of external factors through the second-order factors on the original TAM. The model has been empirically tested using the data collected from a survey of 161 ERP users from a national telecom company, which has been using an ERP system since 1999. The model has been analysed using PLS approach.Findings - The study shows that extended external factors observed through the second-order factors have important influence on ERP usefulness and ERP ease of use; they also have a strong influence on the attitude toward using ERP system by ERP users in the routine (maturity) stage.Originality value - The paper researches the factors which have an impact on ERP solution use in the routine (mature) stage of ERP lifecycle. The paper adds to the literature, in that few previous studies have examined the users' adoption of ERP systems through the TAM or examined external factors that have influence on the intention to use an ERP system or ERP use in the stabilization stage.
The article examines a hybrid approach for optimizing one-dimensional stock cutting. The proposed approach combines two methods: the
pattern-oriented LP-based method, and the
item-oriented sequential ...heuristic procedure. The purpose of such a combined method is its ability to cut order lengths in exactly required number of pieces and to cumulate consecutive residual lengths in one piece which could be used later. The sample problem is presented and solved.
CUTTING AS A CONTINUOUS BUSINESS PROCESS Trkman, Peter; Erjavec, Jure; Gradisar, Miro
Economic and business review for Central and South-Eastern Europe,
12/2009, Volume:
11, Issue:
4
Journal Article
Peer reviewed
Open access
A review of state-of-the-art methods for cutting stock problem optimisation shows that the current methods lead to near-optimum results for the instantaneous optimisation of trim loss. Further ...optimisation of this activity would not bring a considerable improvement. Therefore, the paper treats cutting stock as a continuous business process and not as an isolated activity. An exact method for a general one-dimensional cutting stock problem is presented and tested. The method is mainly suitable for smaller orders. It is then applied to continuous cutting and used to develop a method for assessing cutting costs in consecutive time periods. The modified method finds a good solution over the whole time-span, rather than just local optima. PUBLICATION ABSTRACT
The article examines the sequential heuristic procedure for optimisation of roll cutting in the clothing industry. The issue of roll cutting can be defined as a bicriterial multidimensional knapsack ...problem with side constraints. To handle the bicriterial objective function a lexicographic approach is proposed. An item-oriented solution was found through a combination of approximations and heuristics. A sample problem is presented and solved.
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