Lot Processing in Hybrid Flow Shop Scheduling Problem (original) (raw)

Lot scheduling on a single machine

Information Processing Letters, 2014

In a practical situation, a manufacturer receives different orders from its customers. Different orders may contain different quantities of the product. Therefore, the manufacturer has to decide how to group these orders into different lots based on the capacity of the lot processing machine (such as integrated circuit tester, heated container, etc.) and then decides the sequence of these lots. In this paper, we study a lot scheduling problem with orders which can be split. The objective is to minimize the total completion time of all orders. We show that this problem can be solved in polynomial time.

Integrating Scheduling with Batching and Lot-Sizing: A Review of Algorithms and Complexity

The Journal of the Operational Research Society, 1992

In many practical situations, batching of similar jobs to avoid setups is performed whilst constructing a schedule. On the other hand, each job may consist of many identical items. Splitting a job often results in improved customer service or in reduced throughput time. Thus, implicit in determining a schedule is a lot-sizing decision which specifies how a job is to be split. This paper proposes a general model which combines batching and lot-sizing decisions with scheduling. A review of research on this type of model is given. Some important open problems for which further research is required are also highlighted.

Hybrid algorithms for Job shop Scheduling Problem with Lot streaming and A Parallel Assembly Stage

2017

In this paper, a Job shop scheduling problem with a parallel assembly stage and Lot Streaming (LS) is considered for the first time in both machining and assembly stages. Lot Streaming technique is a process of splitting jobs into smaller sub-jobs such that successive operations can be overlapped. Hence, to solve job shop scheduling problem with a parallel assembly stage and lot streaming, decision makers not only need to determine the processing sequences on machines in first stage, but also need to assign each product to a machine and determine the assembly sequences of the products in second stage and the sub-lot sizes of all jobs and products to minimize the makespan. At first, this problem is modeled as a mixed integer linear programming and GAMS software is applied to solve small problems. Since this problem is classified as NP-hard, four hybrid algorithms based on iterative procedures are suggested to solve the problem in medium and large dimensions. In order to verify the ef...

Simultaneous Lot Sizing and Scheduling in a Flexible Flow Line

Journal of Industrial and Systems …, 2011

This paper breaks new ground by modelling lot sizing and scheduling in a flexible flow line (FFL) simultaneously instead of separately. This problem, called the 'General Lot sizing and Scheduling Problem in a Flexible Flow Line' (GLSP-FFL), optimizes the lot sizing and scheduling of multiple products at multiple stages, each stage having multiple machines in parallel. The objective is to satisfy varying demand over a finite planning horizon with minimal inventory, backorder and production setup costs. The problem is complex as any product can be processed on any machine but with different process rates and sequence-dependent setup times & costs. The efficiency of two alternative models is assessed and evaluated using numerical tests.

Lot streaming in N -1+ N ( m ) hybrid flow shop

Journal of Manufacturing Systems, 2017

This paper deals with N-stage hybrid flow shop (HFS) lot streaming problem to develop a schedule that minimises the makespan. The HFS considered consists of one machine in each of the first (N-1) stages and m machines in stage N. A mixed integer linear programming (MILP) model is proposed and solved using LINGO solver. For large size problems, the LINGO solver takes longer time and hence an algorithm is proposed. The heuristic approach consists of splitting the lots and then sequencing. The lot splitting is based on the average processing time of jobs in the first (N-1) stages and cycle time of stage N. The sum of processing time of all jobs in each stage of the first (N-1) stages is considered for sequencing. Numerical illustrations are carried out to show the percentage deviation of solution obtained using the algorithm from the MILP model. The results show that the algorithm gives near optimal solution to the problems within a very small computational time compared to the MILP model.

Lot streaming in a two-stage assembly system

Annual Reviews in Control, 2020

In this paper, we address a scheduling problem belonging to a two-stage assembly system that can also be viewed as a mass customization system. The first stage of this system consists of a set of subassembly machines, each of which produces a component type. These components are then transferred in sublots to Stage 2, where they are assembled into finished products. Stage 2 consists of multiple parallel machines. Each of these machines represents an assembly facility devoted to a product type. We represent this configuration as a m+n system, where there are m parallel machines at Stage 1 and n parallel machines at Stage 2. Lot-attached and sublotattached setups, and transfer times/costs are encountered on the machines at both the stages. We assume that the subassemblies are transferred in equal-sized sublots to Stage 2. Given a number of lots (jobs), the problem is to determine the number of sublots to use for each lot and the sequence in which to process the lots. We consider two different objective functions, namely, minimize makespan, and minimize the total cost incurred. In view of the fact that both of these problems are NPhard, we develop two column generation-based heuristic methods and show their efficacy over direct solution of the mixed integer programming formulations of the underlying problems. In fact, the results of our computational investigation on the use of these methods on large-sized problems reveal attainment of almost optimal solutions within a few seconds of CPU time. We also present some managerial insights.

Economic lot scheduling with resources in parallel

International Journal of Production Research, 2011

In this paper we consider the economic lot scheduling problem with m machines (or facilities) in parallel. There are n different types of items. Item j has a demand D j per unit time, a holding cost h j per unit time, and a setup cost K j . The machines have different speeds. The speed of machine i is v i . Machine i can produce item j at rate v i P j . We consider three different models.

Lot sizing and scheduling: industrial extensions and research opportunities

International Journal of Production Research, 2011

Production planning and scheduling seeks to efficiently allocate resources while fulfilling customer requirements and market demand, often by trading-off conflicting objectives. The decisions involved are typically operational (short-term) and tactical (medium-term) planning problems, such as work force levels, production lot sizes and the sequencing of production runs.