david james raistrick shrink wrap conveyor line submitted in … · 2012. 12. 29. · shrink wrap...

of 34 /34
Dis Sh Subm the requireme Advanc Faculty of A screte Event simulation David James Raistrick hrink Wrap Conveyor Line mitted in partial fulfilment of ents of Leeds Metropolitan U for the Degree of ced Engineering Manageme Art’s, Environment and Tech December 2011 1 f University ent hnology

Upload: others

Post on 14-Sep-2020

2 views

Category:

Documents


0 download

TRANSCRIPT

Page 1: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

Discrete Event simulation

Shrink Wrap Conveyor Line

Submitted in partial fulfilment of the requirements of

Advanced E

Faculty of Art’s, Environment and

Discrete Event simulation

David James Raistrick

Shrink Wrap Conveyor Line

Submitted in partial fulfilment of the requirements of Leeds Metropolitan University

for the Degree of Advanced Engineering Management

Faculty of Art’s, Environment and Technology

December 2011

1

Submitted in partial fulfilment of Leeds Metropolitan University

ngineering Management

Technology

Page 2: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

2

Authorship Declaration

I, David James Raistrick confirm that this dissertation/assignment and the work

presented in it are my own achievement.

Where I have consulted the published work of others this is always clearly

attributed;

Where I have quoted from the work of others the source is always given. With the

exception of such quotations this dissertation is entirely my own work;

I have acknowledged all main sources of help;

If my research follows on from previous work or is part of a larger collaborative

research project I have made clear exactly what was done by others and what I

have contributed myself;

I have read and understand the penalties associated with Academic Misconduct.

I also confirm that I have obtained informed consent from all people I have

involved in the work in this dissertation following the School's ethical guidelines

Signed:

Date: 02/01/2012

Student ID No: C3153272

Page 3: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

3

Abstract

This report has been published on the results which investigate various

scenarios for how the Shrink Wrap Conveyor line at a large glass bottle

manufacturing plant can transport the pallets out of the building to the dispatch

area where they will be loaded onto the wagons for shipping. This investigation

will be carried out using Discrete Simulation modelling software to reconstruct

real time outputs.

Page 4: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

4

Contents

1.0 INTRODUCTION ....................................................................................... 7

2.0 DISCRETE EVENT SIMULATION ................................................................. 8

2.1 Basic Concept .......................................................................................................................................... 9

2.2 Benefits of Discrete Event Simulation ................................................................................................ 11

2.3 Deterministic and Stochastic Distribution .......................................................................................... 13

3.0 PROJECT ..................................................................................................... 15

3.1 Packing Procedure ................................................................................................................................ 16

3.2 Production Area .................................................................................................................................... 17

3.3 Current data .......................................................................................................................................... 18

3.4 Breakdown Evaluation 1 ...................................................................................................................... 19

3.5 Breakdown Evaluation 2 ...................................................................................................................... 21

4.0 USING BACK UP SHRINK WRAP MACHINE ............................................. 23

4.1 Backup Shrink Wrap Breakdown Evaluation 1 ................................................................................. 25

5.0 USING BACKUP SHRINK WRAP MACHINE METHOD 2 .......................... 27

5.1 Using Backup shrink wrap machine method 2, Evaluation .............................................................. 28

6.0 CONCLUSION .............................................................................................. 32

Page 5: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

5

List of Figures

Fig1 Diagram 4 steps of Discrete Event Simulation 10

Fig2 layout of conveyors and shrink wrap machines 15

Fig3 Break down Evaluation 1 - Line after 24 hours 19

Fig4 Break down Evaluation1 - Queue data after 24 hours 20

Fig5 Break down Evaluation 2 - Line after 24 hours 21

Fig6 Break down evaluation2 - Queue data after 24 hours 22

Fig7 Layout of Back up shrink wrap machine 23

Fig8 Back up machine, Break down Evaluation - Line after 24 hours 25

Fig9 Backup machine, Break down Evaluation - Queue data at 24 hours 26

Fig10 Layout of Back up shrink wrap machine method 2 27

Fig11Back up machine method 2, Break down Evaluation 28

Fig12 Backup machine, Break down evaluation - Queue data 29

Fig13 Model results reducing breakdown to 1 every 5 hours 30

Fig14 Queue data results reducing breakdown to 1 every 5 hours 31

Page 6: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

6

Acknowledgements

Tony Pawinski

Senior Engineering Manager at AGC

Providing technical information on conveyor and process speeds, and proposed

solutions to the problems.

Ian Pickersgill

Cold End Production Manager at AGC

Providing the technical information on the current production times for pallets

produced, timing for fork truck travel and costing for down time.

Page 7: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

7

1.0 Introduction

This report shows how software can be used to model a process or factory without

the need of physically building or utilising hardware or production time. The

particular software been used is called Flexsim which is a USA based company who

state on their website

www.flexism.com

Accessed 01/11/2011

“Flexsim is the most powerful tool for modelling, analyzing, visualizing, and

optimizing any imaginable process - from manufacturing to supply chains, abstract

examples to real world systems, and anything in between.”

Learning outcomes within this module are

• Identify where and how simulation can benefit an organisation and its role in

design, planning and control of production systems.

• Critically evaluate the statistical data a discreet event simulation package can

produce via different data points including throughput, content, machine state

and utilization,

• Interpret the financial analysis data generated by a discreet event simulation

package and defend a strategy of improvement.

• Model discrete event data and processes using techniques at the forefront of

current best practice to recommend optimized scenarios for a given situation.

Within this report a large bottle manufacturing plant based in Leeds will have a

section of its production facility modelled and performance analysed using various

scenarios. The aim of this research and modelling is to determine which would be

the most efficient way to use the backup shrink wrap machine, potentially saving

money and down time.

Page 8: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

8

2.0 Discrete Event Simulation

Discrete event simulation is a method used widely today to analyse and investigate

processes without actually producing a physical model or factory. Software is used

to simulate all factors of a desired project and statically predict outcomes and effect

within the processes.

A proposed project can be completely modelled with all the known and predicted

parameters to evaluate the outcome and the streamline the process to prove or

disprove whether the proposed project could actually work in the real world.

http://www.telecom.otago.ac.nz/tele302/ref/Banks_DES.pdf

Document read 12/12/2011

Jerry Banks Marietta, Georgia 30067, Initially published in the Proceedings of the 1999 Winter

Simulation Conference

Stated

“A discrete-event simulation model is defined as one in which the state variables

change only at those discrete points in time at which events occur.”

Page 9: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

9

2.1 Basic Concept

Discrete Event Simulation works on simple concepts of how long it takes for things to

happen, and what implications arise after a period of time. To break this down it can

be said that there are 4 simple steps.

As shown in Fig1

Website accessed 09/12/2011

http://www.coensys.com/discrete_event_simulation.htm

Page 10: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

10

Fig1 Diagram 4 steps of Discrete Event Simulation

1. Source – This is the beginning of any process were an action or object will

arrive and be distributed into the sequence of event it must go through before

it can be dispatched at the end.

2. Queue – This is the holding area were the object will wait until the next action

is ready to accept it

3. Delay – This is the action which the object must go through

4. Sink – This is the exit or dispatch when the process is complete

For each of these 4 steps parameters can be entered in the model such as

processing/action times, queue limits distribution event and various other parameters

to try and make the model cover all instances within the proposed system that is

been modelled.

Page 11: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

11

2.2 Benefits of Discrete Event Simulation

Advantages of using Discrete Event Simulation are

1. Ability to model complex systems

2. Allows a model to be designed and evaluated without laying a brick in terms of

actually building a process

3. Simulations save time and money.

4. Within the simulation parameters, layouts and equipment can be altered

without changing the real time working system

5. Identify bottle neck areas within the process and experiment how to reduce

them

http://www.ncbi.nlm.nih.gov/pubmed/20659272

Visited 09/12/2011

http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5678916

Visited 09/12/2011

Page 12: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

12

The research and evaluation carried in this report would not be possible to carry out

on the production line, as major re-programming work and electrical work would need

to be carried out just to try the various methods. Activities like this would firstly take

time to do and test and secondly would need reversing when the test and scenarios

have been completed. This would cause major disruption to the factory and

production line. Costing allot of money, lost production and missed delivery times.

However, using Discrete Event Simulation software it is possible to be able to do an

exact model of the machines under investigation, programming actual real to life

speeds, timings and “Stochastic Distributions”. Then the model can be altered

physically as well as the working dynamics altered without actually touching the

equipment in the factory, therefore not costing any money, down time or production

loss.

Page 13: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

13

2.3 Deterministic and Stochastic Distribution

Distributions are how regular or irregular an event could happen, or in the case of this

project how frequent the pallets could arrive. In this project we are producing pallets

at an average rate of 40/hour, so in the ideal world a pallet would arrive exactly every

90 seconds, the pallets would be processed every 65 seconds and sent down the

conveyor line for dispatch leaving exactly 25 seconds of idle time between pallets. If

everything did happen this way then it would be referenced as “Deterministic

Distribution”

http://en.wikipedia.org/wiki/Mathematical_model

Visited 17/11/2011

The following was quoted on the website

“A deterministic model is one in which every set of variable states is uniquely

determined by parameters in the model and by sets of previous states of these

variables. Therefore, deterministic models perform the same way for a given set of

initial conditions.”

Deterministic Distribution is when there is absolutely no randomness to the

distribution, no breakdown scenarios and everything happens in the same way and

time, every time.

It would be very easy to create a model and have it perform in this way but this would

not reflect the real world scenarios of what could actually happen, and without

applying these real life scenarios the model would not generate true

outcomes/results.

Creating the model with high variability, and random arrivals, breakdowns and other

scenarios which would cause the model to behave completely differently but

realistically would be known as “Stochastic Distribution”

Page 14: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

14

http://en.wikipedia.org/wiki/Mathematical_model

Visited 17/11/2011

The following was quoted on the website

“In a stochastic model, randomness is present, and variable states are not described

by unique values, but rather by probability distributions.”

Page 15: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

15

3.0 Project

This project is based on a production line at a major glass bottle manufacturer in

Leeds. There are 8 bottle production lines producing bottles and at the end of each

line the bottles are palletised then sent to the shrink wrap machine before been

transferred on the conveyors out to the dispatch area where they are loaded onto

wagons.

Fig2 layout of conveyors and shrink wrap machines

This conveyor line and layout is shaped exactly how it is shown in this model due to

the positioning of the existing production lines and offices either side of the conveyor

line. There is a small roadway that runs the length of the conveyor line which is an

access route for the fork lift trucks, but this is only wide enough for 1 truck to pass at

any one time. Due to this factory been located very close to Leeds city centre,

expanding the factory is not possible as it is already at its limit for the size of the site,

and changing the layout of the factory would cause excessive down time and the loss

of revenue in loss production would make it un-justifiable.

Page 16: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

16

3.1 Packing Procedure

Each pallet is a standard size and the only variation is the height of each pallet,

which is dependent upon the type of container been produced. A shrink wrap

machine is designed to measure the height of each pallet and cut a plastic packing

bag to the correct length, then fit the bag over the pallet and using heat shrink wrap

the bag around the pallet of containers.

A fork lift truck is used to transport the pallets from each of the production lines and

loads them onto the first loading conveyor. This pallet will then proceed through the

shrink wrap machine then down the conveyor line to the dispatch area where they

are transferred using a second forklift truck from the conveyor and onto the wagons.

Page 17: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

17

3.2 Production Area

Each of the 8 production lines produce glass containers 24 hours a day 7 days a

week. Due to the nature of the procedure and implications of controlling liquid glass,

it is not efficient to stop the moulding procedure at the hot end of the production line.

Therefore the glass containers will never stop been produced. There are also other

implications which can happen at the cold end of the procedure, and the containers

can be held in holding areas, packed by hand or even scrapped and re-cycled. It has

been estimated that if any one of the 8 lines is not producing bottles the production

lost revenue is approximately £75/minute.

A major bottle neck in this whole manufacturing procedure is shrink wrapping the

completed pallets and loading them onto the awaiting wagons. On the shop floor

there is only a maximum capacity to hold 150 pallets. Once this is reached there is a

major problem and palletising on each line has to be stopped and the containers

scrapped. As this is the case backup scenarios must be in place to accommodate

any breakdowns.

Maintenance engineers are on hand full time and this critical part of the production is

classed as priority 1, which means that if any problem occurs on this conveyor line

which causes at to stop, then all other maintenance jobs/breakdowns will be left until

the problem is resolved and the conveyor line is set running again.

A second shrink wrap machine is integrated into the conveyor line in case the main

shrink wrap machine has a major problem.

Page 18: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

18

3.3 Current data

From the 8 production lines 40 pallets are produced per hour, with an average pallet

distribution of 90 seconds with a standard deviation of 15 seconds max.

The following parameters have been set to the loading and unloading fork trucks

• Max Speed = 0.5

• Load Time = 5 seconds

• Unload Time = 5 seconds

When the pallet is placed on the loading conveyor, it must go through the shrink wrap

procedure

• Squaring = 20 seconds

• Bagging and shrinking = 45 seconds

Giving an overall process time of 65 seconds

Then the pallets set off down the conveyor line and outside to dispatch

Each conveyor is 3m long and travels the distance in 5 seconds

When the simulation is run and everything is working as it should be then the whole

process runs faultlessly and well within it capacity, producing no back log of pallets

on the shop floor.

To show the impact on the bag log of pallets on the shop floor various breakdown

scenarios have been introduced and monitored over a 24 hour period. In the event

of a breakdown the whole line would stop sending the pallets outside for dispatch

regardless of where it stops working.

Page 19: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

19

In this case the simulated breakdown is on the squarer at the beginning of the line.

The main repercussion of the line breaking down is that it backs the pallets up on the

shop floor (in this case queue 2).

3.4 Breakdown Evaluation 1

For this break down evaluation, an statistical distribution has been applied which will

execute exponentially over 3600 seconds (1 hour) and the break down will have a

down time of 600 seconds (10 minutes).

This simulation was run for 86400 seconds (24 hours)

Fig3 Break down Evaluation 1 - Line after 24 hours

Page 20: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

20

Fig4 Break down evaluation1 - Queue data after 24 hours

From this data the throughput of pallets at 99.39% and neither of the forklift trucks

are used excessively with idle times of 26.4% for loading fork truck and 28.4% for the

unloading fork truck. The backlog of pallets reached a maximum of 22 during the

down time periods but this was soon cleared when the line was running at full speed.

Page 21: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

21

3.5 Breakdown Evaluation 2

For this break down evaluation, an statistical distribution has been applied which will

execute exponentially over 3600 seconds (1 hour) and the break down will have a

down time of 1800 seconds (30 minutes).

This simulation was run for 86400 seconds (24 hours)

Fig5 Break down Evaluation 2 - Line after 24 hours

Page 22: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

22

Fig6 Break down evaluation2 - Queue data after 24 hours

These breakdown times were pushing the system to the limit and were entered as an

exercise to determine what would happen under these circumstances. A shown from

the data, the backlog reaches the maximum capacity at the 24 hour mark, which is

built up due to not been able to fully clear the backlog between down times. The

throughput of pallets was down to 69% which would also start having an impact on

the Logistic of the delivery wagons.

This extreme scenario would not be allowed to happen without switching over to the

backup shrink wrap machine and repairing the primary machine correctly.

Page 23: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

23

4.0 Using Back up shrink wrap machine

Situated part way down the conveyor line is the backup shrink wrap machine which is

available to be used if the primary shrink wrap machine is going to be down for any

considerable amount of time. When the backup machine is in use then the conveyor

line is disabled through to conveyor 4 and the pallets are loaded direct onto the

bagging process on conveyor 5.

There are 2 major disadvantages when using this backup machine,

1. The process time is slightly longer and impacts on the recovery of time after a

breakdown or stoppage

2. The line has to be manually supervised at all times whilst running due to its

vulnerability of stoppages. This cost the company an estimated £45/hour.

Fig7 Layout of Back up shrink wrap machine

Page 24: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

24

This shrink wrap process works slightly differently as the bagging has to be done

separately which in this case is shown by using an additional process. Also the

heating process is gas which takes longer than the electrical heating process due to

having to run through purging sequences before firing off the burners.

The processing parameters for the backup shrink wrap machine are

• Bagging = 20 seconds

• Bagging Squaring = 10 seconds

• Shrinking = 50 seconds

Giving an overall process time of 80 seconds. Which is 15 seconds longer than

using the primary shrink wrap machine and only gives a 10 second window between

each pallet, thus increasing the recovery time between down time.

Again when the simulation is run and everything is working as it should be then the

whole process runs faultlessly and well within it capacity, producing no back log of

pallets on the shop floor.

Page 25: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

25

4.1 Backup Shrink Wrap Breakdown Evaluation 1

As with the primary shrink wrap simulation, this break down evaluation, an statistical

distribution has been applied which will execute exponentially over 3600 seconds (1

hour) and the break down will have a down time of 600 seconds (10 minutes).

Fig8 Back up Shrink Wrap machine, Break down Evaluation - Line after 24 hours

Page 26: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

26

Fig9 Backup machine, Break down evaluation - Queue data after 24 hours

From observing the data with the breakdown events used, the throughput of pallets is

down to 93% and the shop floor would backup to 76 pallets within the 24 hour period,

this gives a maximum running time for using the backup system of 48 hours 2 days,

before it would start causing serious problems with the overall production facility.

Page 27: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

27

5.0 Using Backup shrink wrap machine method 2

Fig10 Layout of Back up shrink wrap machine method 2

One of the main reasons for stoppages on the conveyor line and the backup shrink

wrap machine is that the control system for the whole system is tied together. So if

any of the conveyors trip off out side or the safety ropes get knocked then the whole

procedure will stop and it takes allot of effort to reset the gas system on the backup

shrink wrap machine.

Because most of the vulnerability is on the sections of conveyor which are outside

the building n investigation has been simulated just using a shorter section of the

conveyor line.

For this method the pallets will be loaded onto Conveyor 5 and removed from

conveyor 10, allowing the remaining conveyors to be isolated and thus potentially

reducing the down time frequency.

This time the unloading fork truck has a narrow path to follow which has been

simulated by using network nodes.

Page 28: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

28

5.1 Using Backup shrink wrap machine method 2, Evaluation

Fig11 Back up machine method 2, Break down Evaluation - Line after 24 hours

Page 29: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

29

Fig12 Backup machine, Break down evaluation - Queue data after 24 hours

Running this scenario with break down evaluation, an statistical distribution has been

applied which will execute exponentially over 3600 seconds (1 hour) and the break

down will have a down time of 600 seconds (10 minutes). Produces better results

and does have the ability to be able to clear the back log with a throughput of 95.8%.

However, using the shortened conveyor method would reduce the stoppage time to a

worst case scenario of once every 5 hours. Feeding the new breakdown parameters

into the model produces the following results.

Page 30: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

30

Fig13 Model results reducing breakdown to 1 every 5 hours

Page 31: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

31

Fig14 Queue data results reducing breakdown to 1 every 5 hours

Running this new criteria through the model shows a significant improvement and the

backlog never gets chance to backup on to the shop floor. The throughput is up to

99% and the maximum backlog reaches 12 which is soon cleared when the line is

running correctly again.

Only the unloading fork truck driver is effected by their idle time been reduced to

8.5%, but the drivers have job switch time tables so they would be swapped around

every 2 hours with a 3rd driver covering breaks every 4 hours.

Page 32: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

32

6.0 Conclusion

Using the Primary shrink wrap machine is the most efficient way to run the conveyor

line, and can sustain large amounts of down time and still recover quickly. In the

event of a major breakdown of this part of the line and the backup conveyor is

required, the chances of line stoppages are highly increased and the duration and

risk of the floor shop filling up with pallets and stopping the bottle production lines is

also increased.

This ultimately costs the company money, as the line has to be manually supervised

at a cost of £45/hour and a further £75/minute would be lost if any of the lines are

forced to start scrapping bottles due to the shop floor reaching capacity.

By modifying the backup shrink wrap machine procedure and only using a shortened

conveyor line, reduces the risk of line stoppages and there for the risk of pallets

backing up shop floor. Also by removing this venerability means that the line will not

need to be supervised by a dedicated full time person and the fork lift truck drivers

can handle this roll, as they would when running with the primary shrink wrap

machine.

Page 33: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

33

References

Internet Website

www.flexism.com

Accessed 01/11/2011

Page 7

Pdf Document

http://www.telecom.otago.ac.nz/tele302/ref/Banks_DES.pdf

Document read 12/12/2011

Page 8

Internet Website

http://www.coensys.com/discrete_event_simulation.htm

Accessed 09/12/2011

Page 9

Internet Website

http://www.ncbi.nlm.nih.gov/pubmed/20659272

Visited 09/12/2011

Page 11

Internet Website

http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5678916

Visited 09/12/2011

Page 11

Page 34: David James Raistrick Shrink Wrap Conveyor Line Submitted in … · 2012. 12. 29. · Shrink Wrap Conveyor Line Submitted in partial fulfilment of the requirements of Advanced E Faculty

34

Internet website

http://en.wikipedia.org/wiki/Mathematical_model

Visited 17/11/2011

Page 13

Internet website

http://en.wikipedia.org/wiki/Mathematical_model

Visited 17/11/2011

Page 14