1 Ban Hiep Lens MPL Term Project AITVN

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    Term project: Solution for delayded delivery of Eyeglass lens manufacturing 1

    Subject: Modern Production Logistic

    Term Project:

    SOLUTION for DELAYED

    DELIVERY OF EYEGLASS LENS

    MANUFACTURING

    Subject: Modern Production Logistic

    Students:

    LE NGOC BAN (Mr)

    NGUYEN THI MY HIEP (Ms)

    Instructor: Prof.Voratas Kachitvichyanukul

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    Term project: Solution for delayded delivery of Eyeglass lens manufacturing 2

    Subject: Modern Production Logistic

    TABLE OF CONTENTS

    I. Statement of the problem. ........................................................................................... 3

    II. Objective of project ..................................................................................................... 3

    III. Methodology. ............................................................................................................ 3

    1. Root cause analysis ................................................................................................ 3

    2. Eyeglass lens manufacturing diagram and process data: ....................................... 4

    3. Methodology. ......................................................................................................... 5

    a) Sale forecast for the year of 2011. ...................................................................... 5

    b) Methodology. ...................................................................................................... 8

    IV. Analysis of result ..................................................................................................... 12

    V. Conclusion and Recommendation: ........................................................................... 13

    1. Conclusion: .......................................................................................................... 13

    2. Recommendations: ............................................................................................... 14

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    Term project: Solution for delayded delivery of Eyeglass lens manufacturing 3

    Subject: Modern Production Logistic

    I. Statement of the problem.Eyeglass lens manufacturing company is in a state of delayed delivery, we are

    hired as a consultant group to determine the root cause of the problem and to find a

    remedy to improve this situation. Base on the historical sale report and by using a

    fishborn diagram, we found the root cause and proposed a best solution to help the

    factory deal with their problem.

    II. Objective of projectThe first priority is to determine the root cause that made the company fall in

    delayded delivery situation, after the cause was found, combining with the historical

    report, we give them the best solution and more than that we provide insight to operate

    the plant with maximizing throughput.

    III. Methodology.1. Root cause analysisBase on the information that was given from the plant and by using the fishborn

    diagram method, we conclude that the problem of delayded delivery is due to poor

    production planning.

    Delayded

    delivery

    Mis- schedulin

    Product shortage

    Poor lo istic

    Poor forecast

    Poor production plan

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    Term project: Solution for delayded delivery of Eyeglass lens manufacturing 4

    Subject: Modern Production Logistic

    2. Eyeglass lens manufacturing diagram and process data:Process diagram:

    Process data:

    Step

    Time Lense (Pairs/Hour)

    Mould Preparation 3.0 minutes/Rack 240Clean Moulds 3.4 minutes/Rack 212Dry Moulds 1.3 minutes/Rack 554Assemble Moulds

    -Gasket (more

    expensive) 1.3 minutes/Rack 554-Tape (Cheaper) 4.8 minutes/Rack 150

    Install Clamp 30 seconds/Rack 1440Fill with Polymer 40 seconds/Rack 1080Bake 20 hours/Rack 160Cool down 4 minutes/Rack 180Disassemble 2.2 minutes/Rack 327Clean and Inspect 4.0 minutes/Rack 180Annealing 3 Hours/Rack 266Measure & Pack 8 minutes/Rack 90

    23.5 hours/Rack 90

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    Term project: Solution for delayded delivery of Eyeglass lens manufacturing 5

    Subject: Modern Production Logistic

    There are some technical information from subject given:

    There are a total of 6 ovens. The capacity of the oven is 600 pairs and the policy isto fill the oven to capacity before starting.

    The lens are removed from the oven and cooled rack by rack. The oven is occupied when the first rack is loaded but the bake process cannot

    start until the oven is filled.

    The oven is freed when all racks of lenses are removed. The annealing oven has unlimited capacity. It is preferable to assemble moulds by using gasket. Tape is used only when there

    is no gasket available to be used.

    3. Methodology.From the data record of the monthly sales for the past three years, we forecast

    demand of product for the next year and our target is to meet this demand by providing

    the best production planning.

    a) Sale forecast for the year of 2011. Past sales record:

    Pairs of Lenses

    2008 2009 2010

    Jan 24596 27082 29788

    Feb 19712 21714 23914

    Mar 21692 19624 23804

    Apr 20042 22044 24310

    May 21516 23738 26180

    Jun 22396 24662 20372

    Jul 33638 37026 40788Aug 30008 33066 36300

    Sep 25520 30116 29931

    Oct 17688 19492 18123

    Nov 21010 23100 25388

    Dec 21890 24090 26422

    Total 279708 305754 325320

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    Term project: Solution for delayded delivery of Eyeglass lens manufacturing 6

    Subject: Modern Production Logistic

    Sesonal index table :Pairs of Lenses

    2008 2009 2010 Monthly average Seasonal index

    Jan 24596 27082 29788 27155 1.073

    Feb 19712 21714 23914 21780 0.861

    Mar 21692 19624 23804 21707 0.858

    Apr 20042 22044 24310 22132 0.875

    May 21516 23738 26180 23811 0.941

    Jun 22396 24662 20372 22477 0.888

    Jul 33638 37026 40788 37151 1.468

    Aug 30008 33066 36300 33125 1.309

    Sep 25520 30116 29931 28522 1.127Oct 17688 19492 18123 18434 0.729

    Nov 21010 23100 25388 23166 0.916

    Dec 21890 24090 26422 24134 0.954

    Total 279708 305754 325320

    Yearly

    Average23309 25480 27110 25300

    Applying the Winters forecast method with Alpha: 0.7; Beta: 0.53 and Gamma:

    0.2, we forecast Ft (total demand of 2011) approximately equal to 374525 pair of lens.

    With the alpha, Beta and Gamma above, we got TS = 0.09 is the minimum value.

    In theory, TS ranging from positive 1 to minus 1, TS here is very small compared with 1,

    so this result is acceptable.

    The monthly demand forecast of 2011

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    Term project: Solution for delayded delivery of Eyeglass lens manufacturing 7

    Subject: Modern Production Logistic

    Demand forecast year of 2011 compare with last 3 years

    30560

    24713 2486426117

    2855227230

    46410

    41905

    36673

    23999

    3088032622

    0

    5000

    10000

    15000

    20000

    25000

    30000

    35000

    40000

    45000

    50000

    1 2 3 4 5 6 7 8 9 10 11 12

    Monthly Demand 2011

    Monthly Demand Monthly average: 31210.

    0

    20000

    40000

    60000

    80000

    100000

    120000

    140000

    160000

    180000

    Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

    Year 2011

    Year 2010

    Year 2009

    Year 2008

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    Term project: Solution for delayded delivery of Eyeglass lens manufacturing 8

    Subject: Modern Production Logistic

    b) Methodology.In detail, well solve the problem as following steps:

    Forecasting the next year demand 2011 from the record data of the monthly salesfor the past three years 2008, 2009, 2010 that we already have done above.

    Calculating the amount of lens needs to be produced a day to meet the demand. Planning of production in detail for each stage, every hour, every day, month and

    year to ensure optimal production.Nghec ng m

    Re-check the production plan that satisfies:Delivering goods on time, adequate output to the customer.

    Reduce inventory in the stock.

    The working schedules are reasonable, optimal.

    Not only planning production to meet market demand, distribution goods on timein 2011, but also need to advise the ability to maximize the plant throughput in the

    future.

    Year 2011 forecast demand is 374 525 pairs per year equal to 1440 pairs per day

    with suppose that the plant runs 5 days per week and 52 weeks per year. Based on data

    forecast for year 2011, average amount needs to be produced is 1440 pairs of lens per

    Year 2008:

    279708Year 2009: 305754

    Year 2010:

    325320

    Year 2011:

    374525

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    Term project: Solution for delayded delivery of Eyeglass lens manufacturing 9

    Subject: Modern Production Logistic

    day. With the global bottleneck capacity of production line of Measure & Packing is 90

    pairs of lens per hour, if we work 8 hours per day the amount will be 720 (90 multiply by

    8) pairs of lens per day. This amount is a haft of demand requirement which is less than

    the requirement so we should arrange the production plan in order to ensure demand perday, that means well supply the finished goods on time. Because of capacity of each

    stage is fixed so we choose to increase the number of working hours for Measure &

    Packing up to double of 16 hours per day. With the production planning for Measure &

    Packing stage of 90*16 = 1440 pairs of lens per day, other stages are always satisfy this

    capcity.

    Exactly, from the production line, we divide the line into two loops: first loop

    from beginning to Baking; and second loop after Baking to the end. From the global

    bottleneck capacity of 90 pairs of lens of second loop, firstly we calculate production

    planning for the 2nd

    loop .

    We have production planning of 2nd

    loop to get 1440 pairs of lens/day as below:

    Time Loop 2 (after baking)

    Time inorder

    InputFrom

    loop 1

    Cool

    Down

    Disass

    embly

    Clean &

    Inspection

    Preapare

    forannealing

    Anneal

    Measure

    &Package

    End

    Products

    180 327 180 266 90

    0 1440 720

    1 1260 180 180 180 180

    720

    90 90

    2 1080 180 180 180 360 90 180

    3 900 180 180 180 540 90 270

    4 720 180 180 180 720 90 360

    5 540 180 180 180 180

    720

    90 450

    6 360 180 180 180 360 90 540

    7 180 180 180 180 540 90 630

    8 0 180 180 180 720 90 720

    9 90 810

    10 90 900

    11 90 99012 90 1080

    13 90 1170

    14 90 1260

    15 90 1350

    16 90 1440

    Total 1440 1440 1440 1440 1440 1440

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    Term project: Solution for delayded delivery of Eyeglass lens manufacturing 10

    Subject: Modern Production Logistic

    From the table above, we see the stages of Cool Down, Disassemly, Clean &

    Inspection, Annealing will run 8 hours per day, but Measure & Packing will run 16 hours

    per day, and well get 1440 pairs per day to suply on time.

    Now we consider production planning of 1st

    loop:

    We have the bottleneck rate of 1st

    loop is rb = 212 pairs per hours of Cleaning

    stage, if we work 8 hours per day so the production amount of 1st

    loop will be 212 x8 =

    1696 pairs per day. This value is higher than the nescessary input of 2nd

    loop (1440 pairs

    per day) so we should control how many pairs should be produced per day, may be two

    Ovens run to get 600 pairs x 2=1200 pairs per day or may be three Ovens run to get 600

    pairs x 3 = 1800 pairs per day, we calculate to optimize the number of Ovens need to be

    run per day in a week as below:

    1 st Loop Bake 2 rd Loop

    Time of

    working/day

    (h)

    ProductionInventory

    (+/- )WIP

    Number of

    OvensInventory

    (+/- )

    Input

    to loop 2

    Monday 8 1696 1800+ 104 3 1440

    Tuesday 8 1696 - 496 1200 2 360 1440

    Wednesday 6.15 1304 +496 1800 3 120 1440

    Thursday 5.66 1200 0 1200 2 480 1440

    Friday 6.15 1304 1200-104 2 240 1440

    Monday 0 1440

    From the table above, we see:

    On Monday, we run full time of 8 hours per day to produce 1696 pairs, add 104pairs produced excess from last Friday to have total of 1800 pairs, so we run 03

    Ovens on Monday.

    On Tuesday, we run full time of 8 hours per day to produce 1696 pairs, but set tobake only 1200 pairs to agree with capacity of loop 2 on next day; 496 pairs left

    will be added in production amount of Wednesday.

    On Wednesday, we run 6,15 hours is enough, the correlative amount produced is1304 pairs per day, add 496 pairs produced excess from last Tuesday to have total

    of 1800 pairs, so we run 03 Ovens on Wednesday.

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    Term project: Solution for delayded delivery of Eyeglass lens manufacturing 11

    Subject: Modern Production Logistic

    On Thursday, we run 5,66 hours, correlative amount produced is 1200 pairs perday and we run two Ovens on Thursday.

    On Friday, we run 6,15 hours , the correlative amount produced is 1304 pairs perday, but set to bake only 1200 pairs to agree with capacity of loop 2 on next day;

    104 pairs left will be added in production amount of next Monday. And now you

    know why we can run 03 ovens from 104 pairs extra from Friday.

    For detail, we make the production time scheduling for the first loop as below:

    Time

    in

    order

    Capacity

    pairs/hPreparation

    Clean Dry AssembleInsta

    ll

    Fill

    Polyme

    Cumu

    lativeBake

    212 554 554 1440 1080

    0 8AM 0 0 0 0 0 0 0

    6001 9AM 212 212 212 212 212 212 212

    2 10AM 212 212 212 212 212 212 424

    2,83 10h50' 176 176 176 176 176 176 600

    3 10h60' 36 36 36 36 36 36 36

    600

    4 12AM 212 212 212 212 212 212 248

    13PMLunch

    break

    5 14PM 212 212 212 212 212 212 460

    5,66 14h39' 140 140 140 140 140 140 600

    6 14h60' 72 72 72 72 72 72 72

    600

    6,15 15h9' 32 32 32 32 32 32 104

    7 15h60' 180 180 180 180 180 180 284

    8 17PM 212 213 214 215 216 217 496

    29' 29' 104 104 104 104 104 104 600

    According to above production time scheduling, we see:

    Monday and Tuesday, we have to work 8hours per day that we product 1696 pairsper day.

    Wednesday and Friday, we have to work 6,15 hours per day, so we stop workingat stages at 15h9PM to get 1304 pairs per day before Baking.

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    Term project: Solution for delayded delivery of Eyeglass lens manufacturing 12

    Subject: Modern Production Logistic

    Thusday, we have to work 5,66 hours per day, so we stop working at stages at14h39PM, to get 1200 pairs per day, before Baking.

    We can devide production calendar as below:

    Day in week

    1st loop Bake 2nd loop

    Mould

    Preparatio to

    Fill Polyme

    Cool down to

    Cleanning &

    Inspec

    AnneallingMeasure

    & Packing

    Monday 8:00 - 17:00

    12:00-8:00

    15:00-11:00

    17:00-13:00

    8:00 - 17:008:00-11:00

    13:00 -16:00

    8:00-17:00

    20:00-5:00

    Tuesday 8:00 - 17:0012:00-8:00

    15:00-11:008:00 - 17:00

    8:00-11:00

    13:00 -16:00

    8:00-17:00

    20:00-5:00

    Wednesday 8:00 - 15:09

    12:00-8:00

    15:00-11:00

    17:00-13:00

    8:00 - 17:008:00-11:00

    13:00 -16:00

    8:00-17:00

    20:00-5:00

    Thursday 8:00 - 14:3912:00-8:00

    15:00-11:008:00 - 17:00

    8:00-11:00

    13:00 -16:00

    8:00-17:00

    20:00-5:00

    Friday 8:00 - 15:0912:00-8:00

    15:00-11:008:00 - 17:00

    8:00-11:00

    13:00 -16:00

    8:00-17:00

    20:00-5:00

    Monday 8:00 - 17:00

    12:00-8:00

    15:00-11:00

    17:00-13:00

    8:00 - 17:008:00-11:00

    13:00 -16:008:00-17:0020:00-5:00

    IV.

    Analysis of result

    According to the scheduled working calendar above, the plant can produce 374400

    pairs of lens per year. Meanwhile, annual demand forecast 2011 around : 374525 pairs of

    lens per year, the deviation between quantity of production and demand is negligible, so

    this production capacity is acceptable.

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    Term project: Solution for delayded delivery of Eyeglass lens manufacturing 13

    Subject: Modern Production Logistic

    Meet demand of the year 2011 with:- 1st loop: working from 8 am to 5 pm everyday to run 2 or 3 oven/day- 2nd loop: working from 8 am to 5 pm everyday, except Mrs&Pack works

    16hours per day.

    - Bake: running 20 hours- Only Measure&Pack process needs 2 working shifts.- 1st loop has no need to be operated all entire 2011.- Only 3 out of 6 ovens needed at Bake at 80C process

    Production plan scheduled Delayed delivery solved, customer service is satisfied

    The problem of delayded delivery was solved. But, be aware of critical monthly

    demand during the year of 2011, from the monthly forecast diagram the highest demand

    period is from July to September. To offset this peak, the plant have to make to stock

    from January to June.

    Solution for maximizing the plant throughput:

    Cycle WIP = 7200 pairs per week. Cycle time = 123 hours

    From the Littles law Throughput = , we get:

    Throughputactual = 7200/123 = 58.53 pairs per hour. Throughputbest case = rb = 90 pairs per hour. ThroughputPWC = +1 = 69.57 pairs/h, where Wo = rb * To = 90*23.5 = 2115

    Throughputactual < ThroughputPWC, So still room for improvement.

    V. Conclustion and Recommandation:1. Conclustion:

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    Term project: Solution for delayded delivery of Eyeglass lens manufacturing 14

    Subject: Modern Production Logistic

    The problem of delayded delivery was solved with the strict timely workingcalendar required

    Steady-state assumed Unable to improve the bottleneck speed Unlimited mould supply Unlimited gasket supply 12:00 13:00 is a lunch break Throughput can be improved for greater demand of the next years.

    2. Recommendations: Logistics system should be checked. Forecast system should be checked. Capacity of Measure&Pack process should be improved. Hidden capacity in many processes can be yielded in the future.

    The end!