application of lean in fishing net company.

1. Lean production system design for fishing
net manufacturing using lean principles and
simulation optimization
Ilyas Hussain
P2MFG15006

2. Introduction
 The common challenges that companies face are market com-
petition, increased pressure on inventory, increased service
levels, and reduced work in process (WIP). Lean
manufacturing is one of the approaches that can help
companies respond appropriately to these challenges.
 The focus of the approach is on cost reduction, by eliminating
activities that do not add value by linking and balancing work
stages, so that products from one stage are consumed directly
by the next stage, until the end of the production line is
reached.

3.  Fishing net manufacturing is a high make-to-order (MTO)
environment, because net size and type change according to
the ocean environment, fish kinds and ship size.
 MTO manufacturing need not be a pull production system as
there are many (or some) simultaneous orders in the
manufacturing process and orders may be different in size and
specifications.
 Higher WIP and longer cycle times always result in a lower
service level and produce lower customer satisfaction in MTO
environments.

4.  Through the production procedure the production units
become bigger and bigger and the processing time in most
steps are quite long.
 This provides the motivation for this research, to design a lean
manufacturing system for this industry.
 The objective of the present study is to model a non-typical
production system – a fishing-net manufacturing system – and
to propose a lean production system design which is optimized
by simulation optimization.

5. Current State Map of Fishing Net
 There are various fishing nets each net has a unique
application which is based on the ocean environment, fish type
and ship size.
 Therefore, the same customer could order nets of different
types or different sizes. Each order requires different raw
material types, twine sizes, mesh sizes, mesh depths and mesh
lengths.
 Net cage is one kind of fishing net which is the main product
of the case study company.
 The general diameter varies from 10 m to 30 m, depth varies
from 4 m to 10 m, while mesh varies from 2 mm to 30 mm.

7.  There are six workstations for net cage manufacturing. They
are (1) Twisting, (2) Braiding, (3) Net knitting,(4) Dyeing, (5)
Heating and (6) Suturing. All manufactured net cages follow
the sequence of workstation above, from 1 to 6.
 There two options for the width of a net: 1 or 2 m. According
to the specification of the knitting machines in the case
company the standard size can be 10 m × 1 m or 10 m × 2 m.
 Every knitting machines can knit one single 10 m × 2 m net or
two 10 m × 1 m nets simultaneously.

8.  Dyeing workstation, a number of nets in standard size can be
dyed together, but the total weight of the nets cannot exceed
the capacity of the dyeing machine.
 One single 10 m × 2 m net or two 10 m × 1 m nets can be
heated simultaneously in heating machine.
 Finally, the nets with standard size are sutured to form net
cages according to the request of the customers.

10.  According to the current state map, reducing the waiting time
in front of the each workstation is an opportunity to reduce the
lead time and, consequently, to increase the service level.
 Two performance indicators, average WIP level and average
service level, are taken into consideration in this case study.
 WIP level is defined as the total volume of semi-finished
goods in the production system. Service level is defined as the
percentage of orders that are completed before their
corresponding due date.

11.  As the company did not collect data on service level and WIP,
this research developed a simulation model to evaluate it.
Commercial software, Arena is adopted as the simulator for
the present study.
 To evaluate the performance of each scenario, a run length of
750 days with 3–12 replications was adopted for the
simulation model.
 The estimated service level and WIP are 68% and 63,971 kg
respectively.

13. Lean Principles
 There are five phase for implementation of VSM. The phases
are (1) selection of product family; (2) current state mapping;
(3) future state mapping; (4) definition of working plan; and
(5) achievement of working plan.
 The lean techniques to be used are defined in the third phase
which contains seven guidelines to define the future state map.

14.  Guideline 1: Produce to your TAKT time.
• “Takt time” is used to synchronize the pace of production with
the pace of sales.
• Takt time = available working time per day /customer demand
rate per day
 Guideline 2: Develop continuous flow where possible.
• Continuous flow refers to producing one piece at a time to
reduce the inventory of WIP and production CT. However
continuous flow requires a great deal of creativity to achieve
and sometimes it requires plant layout redistribution. In this
research, this guideline is not applicable and is not taken into
consideration in the case study.

15.  Guideline 3: Use a supermarket to control production where
continuous flow does not extend upstream.
• A “supermarket” is nothing more than a buffer or storage area
located at the end of the production process for products that
are ready to be shipped.
• Supermarkets use a kanban system to fix the inventory level. If
the number of kanbans in a supermarket is too high, it causes
higher inventory cost.
• If the number of kanban in the supermarket is too low the
downstream production process will be subject to delays.

16.  Guideline 4: Try to send customer scheduling to only one
production process.
• The process time is set by one of the production processes.
That process is called the “pacemaker process”. The
pacemaker process synchronizes the pace of the entire
manufacturing process and there are no supermarkets
downstream of the pacemaker process.
• Therefore, selecting different workstations as the pacemaker
process will have an important influence on the performance
of the entire manufacturing system.

17.  Guideline 5: level the production mix.
• Leveling the product mix means dividing the volume of all the
product types based on their kanban size, and then producing
them evenly over a time period.
• The more level the product mix is, the greater is the ability to
respond to different customer requirements with a short lead
time.
• For example, if there are three product types and the
production sequence can be A-A-A-B-B-B-C-C-C or A-B-C-
A-B-C-A-B-C.
• The latter is more level and allows the process to proceed
smoothly with smaller supermarkets.

18.  Guideline 6: Level the production volume.
• Leveling the production volume is related to Guideline
number1. It means that production should be based on a fixed
pace, the takt time.
 Guideline 7: Develop the ability to make “every part
everyday” in fabrication processes upstream of the pacemaker
process.

19. Future State Map Optimization
 From lean principles we identified five key controllable factors
as: (1) production unit size, (2) the pacemaker process, (3) the
number of batches for an order split, (4) the production
sequence, and (5) supermarket size, to optimize the proposed
fishing-net manufacturing system.
 According to the guidelines for designing the future state map,
the production unit should be as small as possible to level the
product mix.
 The production unit of each workstation depends on the
standard net size and the processing times of the standard net
size could be different in every workstation.

20.  As regard the pacemaker process, this research selects Knitting
workstation, Dyeing workstation and Suturing workstation as
the candidates.
 Knitting workstation usually has the highest machine
utilization. Dyeing workstation is batch processing. Its
capacity is batch-size dependent. Suturing workstation is the
most labor intensive workstation.
 the potential bottleneck could shift among the three
workstations which are thus considered as the candidate
pacemaker locations.

21.  The number of batches to be allowed will decide the
transportation volume between workstations.
 More batches allow for a more level product mix, but will
cause more changeovers. The changeover times between
different products are different.
 An appropriate production sequence can reduce the total
changeover time.
 This research selects earliest due date (EDD), first in fist out
(FIFO) and shortest process time (SPT) as alternative criteria
for designing the future state map.

23.  Four factors (production unit, pacemaker process, number of
batches and production sequence) are taken into consideration
in the experimental approach to designing the future state map.
 For each scenario, Opt Quest is used to find the best super-
market size and the corresponding performances are viewed as
the performance of each scenario.
 The Taguchi method aims to find an optimal combination of
parameters that have the smallest variance in performance. The
signal-to-noise ratio (S/N ratio, ) is an effective way to find
significant parameters by evaluating minimum variance.
 A higher S/N ratio means better performance for combinatorial
parameters .

25. Effect of s/n ratio of service level
Effect of s/n ratio of WIP level

26.  A2B1C1D2 is the best design for the future state map to
maximize the service level.
 A1B1C2D2is the best design for the future state map to
minimize the WIP.
 The optimizing results produced by Opt Quest show that the
design of A2B1C2D2 increases service level from 68% to 90%
and reduces WIP from 63,971 kg to 42,269.31 kg.
 The non-value adding time reduces from 44% (19.78 days)to
35.46% (13.78 days).

27.  Note that the optimal design of production unit (factor A) is
level 2 (10 × 2 m) which is bigger than level 1 (10 × 1 m).
Although the guideline number 7 encourages the production
unit to be smaller the better.
 The size of a final net cage range from 120 to 900 m2.The
smaller production unit would cause more processing time for
suturing process and would deteriorate the suturing
workstation performance.

29. Conclusion
 Lean manufacturing has been applied successfully in many
manufacturing industries. It focuses on cost reduction by
eliminating non-value adding activity. In general, waiting is
the most common non-value adding activity.
 Based on the guidelines for implementing lean manufacturing,
some important production factors are selected for designing
the future state VSM.

30.  Using experimental design and a simulation optimization tool,
these important factors are optimized. According to analysis
based on the simulation, the future state map not only
increases service level but also reduces the WIP.
 In the case study, the selected factors can be changed to any
level without extra investment. That means the case company
can implement the future state map to achieve lean
manufacturing without any financial pressure. This could be
the first step to achieving lean manufacturing.

31. Thank you