Analysis of critical machine reliability in manufacturing cells
Journal of Industrial Engineering and Management
JIEM
2013-0953
Analysis of Critical Machine Reliability in Manufacturing Cells
Manocher Djassemi 0
Hamid Seifoddini 1
0 California Polytechnic State University , United States
1 University of Wisconsin , Milwaukee , United States
Purpose: In an increasingly competitive business environment, machine reliability problem merits special attention in operations of manufacturing cells. This is mainly due to flow line nature of the cellular layout, interdependency of downstream and upstream of machines related to each other. This study investigates the effect of critical machine reliability improvement on production capacity and throughput time in manufacturing cells. Design/methodology/approach: A discrete-event simulation model was developed to investigate the effectiveness of a reliability plan focusing on the most critical production machines in improving the performance level as an alternative to increasing the reliability of all machines. Four machine criticality policies are examined in the simulation experiments. Findings: The results of this experimental study indicated that an improvement of reliability of a limited number of machines leads to an increase in overall production capacity and speed in cellular manufacturing operations. A reliability plan, that focuses on a set of critical machines, potentially offers a more economical alternative to increasing the reliability of all machines in such facility. Research limitations/implications: The results demonstrate that to achieve higher production capacity and shorter throughput times, managers should consider directing more resources to increase the reliability of critical machines, particularly, those with shorter mean time to failure and higher utilization. Limitations of the study include the exclusion of cost of improving machine reliability and maintenance resources; and the cost of production losses due to machine breakdown. Originality/value: The designed simulation model is unique in representing the dynamics of a real world manufacturing cell environment by encoding operational functions such as machine failure, maintenance resource allocation, material flow, job sequencing and scheduling. A new machine availability metric is defined as well.
manufacturing cells; reliability; simulation modeling
1. Introduction
With the advent of global competition and advancements in technology, the reliability of production facility, and
predictability in available resources have become critical in meeting the market demand. One such production
facility is manufacturing cell also known as cellular manufacturing system (CM) in which autonomous production
cells, referred to as machine cells, are built using a group of dedicated dissimilar machines arranged in a series
layout. In manufacturing firms, the cellular arrangement provides a solution for processing high-variety product
mixed in small batches, as small as one part, which leads to an efficient one-piece flow production. However, the
independent nature of a machine cell and its dedication to producing a few part families make the machine
reliability more critical in CM compared to other types manufacturing systems. Specifically, in cellular configuration,
when a machine is down for scheduled maintenance or an unexpected repair, the work-in-process stalls until the
machine returns to operational status. In such event, there is no alternative machine within the same cell to process
a part. This can be particularly disruptive to the flow line and serial nature of process sequences in manufacturing
cells.
A number of simulation studies indicate that the performance of a cellular system is more seriously affected by the
deterioration of machine reliability than the performance of other manufacturing systems. Seifoddini and Djassemi
(1996) suggested that machine reliability should be considered more carefully when operating a CM system due to a
dedication of machines to machine cells.
Das, Lashkari and Sengupta (2007
a) presented a flexible process routing
approach, which minimized the impact of machine failure. The authors proposed a CM design solution that
consisted of assigning machines to cells, and selecting each part of the process route with highest overall system
reliability. In a study by Diallo, Pierreval and Quilliot (2001), the design of manufacturing cells in presence of
unreliable machines was discussed. The study captured the different states of the system resulting from the
availability or unavailability of unreliable machines to build efficient cell configurations when disturbances occur.
The study presented by Seifoddini and Djassemi (2001) concluded that the impact of machine breakdown was not
limited to lower production rate, but it was also interrupted by the scheduling and productivity of the entire
manufacturing system.
Das, Lashkari and Sengupta (2007
b) pointed an importance of machine reliability in CM
systems, where parts we (...truncated)