Contenu connexe Similaire à Optimization of planning in garment manufacturing Similaire à Optimization of planning in garment manufacturing (20) Plus de dr Gordana Colovic Plus de dr Gordana Colovic (20) 1. Volume 5 • Issue 3 • 1000199
J Textile Sci Eng
ISSN: 2165-8064 JTESE, an open access journal
Research Article Open Access
Colovic, J Textile Sci Eng 2015, 5:3
http://dx.doi.org/10.4172/2165-8064.1000199
Opinion Open Access
Textile Science & Engineering
JournalofTe
xtile Science &
Engineering
ISSN: 2165-8064
Introduction
The daily production of clothing deals with many work orders, so it
is necessary to complete Scheduling (shop floor control). Priorities can
be determined on the basis of several rules:
- FIFO (first-in, first-out),
- LIFO (last-in, first-out),
- DDATE (earliest due date) - which product must be made first,
- CUSTPR (highest customer priority) - first the product for priority
customers,
- SETUP (similar setup) - first the similar products which require a
minimum setting of machines,
- SPT (shortest processing time) - priority for products that last for
the shortest period,
- LPT (Longest Processing Time) - priority for products that last for
the longest period.
Priority DDATE can have variations:
- SLACK (Slack minimum) - priority for jobs that have less time
margin:
- CR (smallest critical ratio) - priority for jobs with smaller ratio of
the remaining time to maturity and remaining processing time:
If CR > 1, then the product is made before the deadline
If CR < 1, then it’s late
If CR = 1, then it is done on time
Already deployed operations often change their order, since
there are new jobs coming into production. Scheduling is performed
according to the above rules, which can be modified in a way that
corresponds to the number of resources or the complex global rules:
- Expanded SPT (shortest processing time) - jobs are divided into
A, B and C, according to their duration. Jobs A are performed with a
minimum duration, but every few hours the production is interrupted
and job B is performed. Jobs C are performed every day each.
- WINQ (work-in-next-queue) - sees the duration of performing
job at the next resource.
- NOPN (fewest number of remaining operation) - according to the
number of resources that are yet to be used.
- S/OPN (Slack per remaining operation) - according to the time
reserve for the rest of the job.
- RWK (Remaining work) - a variant of SPT, the duration of
performing whole job on all resources.
Resources which are bottlenecks have a negative effect on the
process efficiency, because they limit its real capacity and do not provide
a high-quality, fast and flexible production. Goldratt’s limiting theory
[1], defines a bottleneck in the process or in the company, because it
assumes that the goal of every company is to “create money”. Limiting
theory is what prevents the system or process to reach a higher level of
performance, i.e. it focuses on real capacity, inventory and production
costs. Goldratt’s theory coordinates production flow with demand
according to the following principles:
1. It is necessary to harmonize the flow of the process, not the
capacities of phases of the process,
2. Efficiency of bottleneck is not determined by its capacity, but by
other constraints,
3. Utilization and use of resources are different concepts,
4. An hour wasted due to the bottleneck is an hour lost for the
entire process,
5. An hour saved at bottleneck is an illusion,
6. Series of transfer do not need to be equal to the size of the
production series,
7. Sizes of production series do not need to be fixed,
8. Lead time of process is the result of designing process,
9. When designing a process one should always bear in mind the
constraints (bottlenecks) [2].
Technological process of production of clothing uses the technique
of parallel ways of moving cut parts of garment from one operation
to another together with scheduling and deployment of technological
operations on the production capacities by checking the availability
of resources. Thereby the making or installation of certain parts of
garment is performed by an arbitrary number of operations whose
scheduling is known to everybody, as well as the duration of individual
operations. The optimization of technological operations is shown in
Figures 1 and 2.
The most frequently used expressions for the network activities
are CPM (Circle Plan Methods), PDM (Precedence Diagramming
Method) and PERT (Program Evaluation and Review Technique), and
the types of networks are:
o AOA (Activity-on-arc).
o AON (Activity-on-node).
Optimization of Planning in Garment Manufacturing
Gordana Colovic*
The College of Textile-Design, Technology and Management, Belgrade, Serbia
*Corresponding author: Gordana Colovic, The College of Textile-Design,
Technology and Management, Belgrade, Serbia, E-mail: gordanacolovic@gmail.com
Received April 27, 2015; Accepted April 28, 2015; Published May 15, 2015
Citation: Colovic G (2015) Optimization of Planning in Garment Manufacturing. J
Textile Sci Eng 5: 199. doi:10.4172/2165-8064.1000199
Copyright: © 2015 Colovic G. This is an open-access article distributed under the
terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original author and
source are credited.
2. Citation: Colovic G (2015) Optimization of Planning in Garment Manufacturing. J Textile Sci Eng 5: 199. doi:10.4172/2165-8064.1000199
Page 2 of 2
Volume 5 • Issue 3 • 1000199
J Textile Sci Eng
ISSN: 2165-8064 JTESE, an open access journal
References
1. Goldratt EM (1997) Critical Chain, The North River Publishing Corporation,
USA
2. Colovic G (2010) Management of technology systems in the garment industry,
Woodhead Publishing Ltd., India
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Citation: Colovic G (2015) Optimization of Planning in Garment Manufacturing. J
Textile Sci Eng 5: 199. doi:10.4172/2165-8064.1000199
TECHNOLOGICAL OPERATION
ORDER ACTIVITIES
CRITICAL PATH
NETWORK PLAN DURATION OF
ACTIVITY
TIME
USE
RESOURCES
FINAL NETWORK PLAN
ACTIVITY
OPTIMIZATION
Figure 1: Optimization of technological operations.
Figure 2: Network diagram.
![Volume 5 • Issue 3 • 1000199
J Textile Sci Eng
ISSN: 2165-8064 JTESE, an open access journal
Research Article Open Access
Colovic, J Textile Sci Eng 2015, 5:3
http://dx.doi.org/10.4172/2165-8064.1000199
Opinion Open Access
Textile Science & Engineering
JournalofTe
xtile Science &
Engineering
ISSN: 2165-8064
Introduction
The daily production of clothing deals with many work orders, so it
is necessary to complete Scheduling (shop floor control). Priorities can
be determined on the basis of several rules:
- FIFO (first-in, first-out),
- LIFO (last-in, first-out),
- DDATE (earliest due date) - which product must be made first,
- CUSTPR (highest customer priority) - first the product for priority
customers,
- SETUP (similar setup) - first the similar products which require a
minimum setting of machines,
- SPT (shortest processing time) - priority for products that last for
the shortest period,
- LPT (Longest Processing Time) - priority for products that last for
the longest period.
Priority DDATE can have variations:
- SLACK (Slack minimum) - priority for jobs that have less time
margin:
- CR (smallest critical ratio) - priority for jobs with smaller ratio of
the remaining time to maturity and remaining processing time:
If CR > 1, then the product is made before the deadline
If CR < 1, then it’s late
If CR = 1, then it is done on time
Already deployed operations often change their order, since
there are new jobs coming into production. Scheduling is performed
according to the above rules, which can be modified in a way that
corresponds to the number of resources or the complex global rules:
- Expanded SPT (shortest processing time) - jobs are divided into
A, B and C, according to their duration. Jobs A are performed with a
minimum duration, but every few hours the production is interrupted
and job B is performed. Jobs C are performed every day each.
- WINQ (work-in-next-queue) - sees the duration of performing
job at the next resource.
- NOPN (fewest number of remaining operation) - according to the
number of resources that are yet to be used.
- S/OPN (Slack per remaining operation) - according to the time
reserve for the rest of the job.
- RWK (Remaining work) - a variant of SPT, the duration of
performing whole job on all resources.
Resources which are bottlenecks have a negative effect on the
process efficiency, because they limit its real capacity and do not provide
a high-quality, fast and flexible production. Goldratt’s limiting theory
[1], defines a bottleneck in the process or in the company, because it
assumes that the goal of every company is to “create money”. Limiting
theory is what prevents the system or process to reach a higher level of
performance, i.e. it focuses on real capacity, inventory and production
costs. Goldratt’s theory coordinates production flow with demand
according to the following principles:
1. It is necessary to harmonize the flow of the process, not the
capacities of phases of the process,
2. Efficiency of bottleneck is not determined by its capacity, but by
other constraints,
3. Utilization and use of resources are different concepts,
4. An hour wasted due to the bottleneck is an hour lost for the
entire process,
5. An hour saved at bottleneck is an illusion,
6. Series of transfer do not need to be equal to the size of the
production series,
7. Sizes of production series do not need to be fixed,
8. Lead time of process is the result of designing process,
9. When designing a process one should always bear in mind the
constraints (bottlenecks) [2].
Technological process of production of clothing uses the technique
of parallel ways of moving cut parts of garment from one operation
to another together with scheduling and deployment of technological
operations on the production capacities by checking the availability
of resources. Thereby the making or installation of certain parts of
garment is performed by an arbitrary number of operations whose
scheduling is known to everybody, as well as the duration of individual
operations. The optimization of technological operations is shown in
Figures 1 and 2.
The most frequently used expressions for the network activities
are CPM (Circle Plan Methods), PDM (Precedence Diagramming
Method) and PERT (Program Evaluation and Review Technique), and
the types of networks are:
o AOA (Activity-on-arc).
o AON (Activity-on-node).
Optimization of Planning in Garment Manufacturing
Gordana Colovic*
The College of Textile-Design, Technology and Management, Belgrade, Serbia
*Corresponding author: Gordana Colovic, The College of Textile-Design,
Technology and Management, Belgrade, Serbia, E-mail: gordanacolovic@gmail.com
Received April 27, 2015; Accepted April 28, 2015; Published May 15, 2015
Citation: Colovic G (2015) Optimization of Planning in Garment Manufacturing. J
Textile Sci Eng 5: 199. doi:10.4172/2165-8064.1000199
Copyright: © 2015 Colovic G. This is an open-access article distributed under the
terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original author and
source are credited.](https://image.slidesharecdn.com/optimization-of-planning-in-garment-manufacturing-150730001558-lva1-app6892/85/Optimization-of-planning-in-garment-manufacturing-1-320.jpg)
