Minimizing production flow time in a process and assembly job shop
01 Aug 1998-International Journal of Production Research (Taylor & Francis Group)-Vol. 36, Iss: 8, pp 2315-2332
TL;DR: In this article, the problem of scheduling a set of N final products on M machines in a job shop environment that involve both machining and assembly operations is addressed, and a mathematical model is developed in an effort to obtain optimal solutions.
Abstract: Scheduling is one of the most important issues in the planning and operation of production systems, but in medium to large shops, the generation of consistently good schedules has proven to be extremely difficult. The problem is that optimal scheduling solutions involve costly and impractical enumeration procedures. In the literature, most scheduling problems only address jobs with serial or sequential operations. Rarely do they consider jobs in which machining and assembly operations are simultaneously involved. This lack of attention to scheduling problems that involve both machining and assembly goes against what one would normally find in most job shops. In this paper, the problem of scheduling a set of N final products on M machines in a job shop environment that involve both machining and assembly operations is addressed. The objective pursued is the minimization of production flow time (makespan). A mathematical model is developed in an effort to obtain optimal solutions. Because this type of model...
Citations
More filters
TL;DR: This paper proposes a unified notation for assembly scheduling models that encompass all concurrent-type scheduling problems, and uses this notation, the existing contributions are reviewed and classified into a single framework so a comprehensive, unified picture of the field is obtained.
78 citations
TL;DR: A consolidated survey of assembly flow shop models with their solution methodology is provided and some problems receiving less attention are presented and several salient research opportunities are proposed.
Abstract: The past few years have witnessed a resurgence of interest in assembly flow shop scheduling as evidenced by increasing number of published articles in this field. A basic assembly flow shop consist...
76 citations
Cites background from "Minimizing production flow time in ..."
...If at least two jobs with assembly operations have distinctive process flow, then the problem is modelled as an assembly job shop, see Cummings and Egbelu (1998), Lu, Huang, and Yang (2011), and Wong and Ngan (2013), and for a recent survey of assembly job shop see Khodke and Bhongade (2013)....
[...]
...If at least two jobs with assembly operations have distinctive process flow, then the problem is modelled as an assembly job shop, see Cummings and Egbelu (1998), Lu, Huang, and Yang (2011), and Wong and Ngan (2013), and for a recent survey of assembly job shop see Khodke and Bhongade (2013). Assembly stage can be combined with other types of process flows such as an open shop....
[...]
01 Mar 2013
TL;DR: A hybrid genetic algorithm (HGA) and a hybrid particle swarm optimization (HPSO) are proposed and developed to solve AJSSP in consideration of lot streaming technique, and computational results show that for all test problems under various system conditions, HGA can significantly outperform HPSO.
Abstract: Very often, studies of job shop scheduling problem (JSSP) ignore assembly relationship and lot splitting. If an assembly stage is appended to JSSP for the final product, the problem then becomes assembly job shop scheduling problem (AJSSP). To allow lot splitting, lot streaming (LS) technique is examined in which jobs may be split into a number of smaller sub-jobs for parallel processing on different stages such that the system performance may be improved. In this study, the system objective is defined as the makespan minimization. In order to investigate the impact of LS on the system objective under different real-life operating conditions, part sharing ratio (PSR) and system congestion index (SCI) are considered. PSR is used to differentiate product-specific components from general-purpose, common components, and SCI for creating different starting conditions of the shop floor. Both PSR and CSI are useful as part sharing (also known as component commonality) is a common practice for manufacturing with assembly operations and system loading is a significant factor in influencing the shop floor performance. Since the complexity of AJSSP is NP-hard, a hybrid genetic algorithm (HGA) and a hybrid particle swarm optimization (HPSO) are proposed and developed to solve AJSSP in consideration of LS technique. Computational results show that for all test problems under various system conditions, HGA can significantly outperform HPSO. Also, equal-sized lot splitting is found to be the most beneficial LS strategy especially for medium-to-large problem size.
67 citations
TL;DR: For the first time, the application of Lot Streaming technique is extended to a Resource-Constrained Assembly Job Shop Scheduling Problem (RC_AJSSP) and an innovative approach with Genetic Algorithm (GA) is proposed.
67 citations
TL;DR: Experimental results suggest that equal size LS outperforms varied size LS with respect to the objective function, and this paper combines LS and AJSP, extending LS applicability to both machining and assembly.
Abstract: Assembly job shop scheduling problem (AJSP) is an extension of classical job shop scheduling problem (JSP). AJSP starts with JSP and appends an assembly stage to the completed jobs. Lot streaming (LS) technique is a process of splitting jobs into smaller sub-jobs such that successive operations can be overlapped. This paper combines, for the first time, LS and AJSP, extending LS applicability to both machining and assembly. To solve this complex problem, an efficient algorithm is proposed using genetic algorithms and simple dispatching rules. Experimental results suggest that equal size LS outperforms varied size LS with respect to the objective function.
61 citations