Modeling and simulation for optimization of a mattress production line based on flexsim software at dunlopillo (vietnam) LTD

MINISTRY OF EDUCATION AND TRAINING HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION FACULTY FOR HIGH QUALITY TRAINING INDUSTRIAL MANAGEMENT MODELING AND SIMULATION FOR OPTIMIZATION OF A MATTRESS PRODUCTION LINE BASED ON FLEXSIM SOFTWARE AT DUNLOPILLO (VIETNAM) LTD SUPERVISOR: MBA NGUYEN DANH HA THAI STUDENT: DO THUY LINH SKL008186 Ho Chi Minh City, August, 2021 MINISTRY OF EDUCATION AND TRAINING HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION FACULTY FOR HIGH QUALITY TRAINING GRADUATION THESIS Topic: MODELING AND SIMULATION FOR OPTIMIZATION OF A MATTRESS PRODUCTION LINE BASED ON FLEXSIM SOFTWARE AT DUNLOPILLO (VIETNAM) LTD Student : Do Thuy Linh ID : 17124047 Year : 2017 Major Instructor : Industrial Management : MBA Nguyen Danh Ha Thai Ho Chi Minh City, August, 2021 INSTRUCTOR’S COMMENTS Ho Chi Minh City, day … month … year … Instructor i MEMBER OF THE THESIS COMMITTEE’S COMMENTS -Ho Chi Minh City, day … month … year … Member of the Thesis committee ii ACKNOWLEDGEMENT The process of completing the graduation thesis is the most important stage in every student's life It is the hardest time for me because I did present the biggest challenge that I’ve never met with full of efforts Graduation thesis gives me an opportunity to review all knowledge and skills in four years of university before starting a career First of all, I would like to express my sincerity, thanks to teachers of the Faculty for High Quality Training and the Faculty of Economy who always have enthusiastically taught and equipped students with all necessary knowledge and experience Secondly, I would like to express my gratitude to my instructor Mr Nguyen Danh Ha who gave me all useful guidance and enthusiastic support They are very valuable suggestions not only in the process of making this thesis but also as a stepping stone for me in the process of studying and setting up a career in the future Finally, thank you to my family and my friends who are always by my side and encourage me to overcome all my hard times Because of the time limit, the difficulty in approaching such a new researching direction i.e Simulation and lack of experience, the thesis cannot avoid mistakes and shortages Therefore, I am extremely appreciated to receive comments and recommendation from you to help me to complete this graduation thesis as well as possible Thank you so much, Best regards Ho Chi Minh City, 18 August 2021 Student DO THUY LINH iii ACRONYM Avg BN DPR DVL MPR M&S Pcs PPR QC Qty iv LIST OF TABLES Table The advantages and disadvantages of four basic layout types 13 Table 2 Characteristics of a manufacturing system model 19 Table The advantages & disadvantages of Simulation 21 Table The working schedule 24 Table The average daily yield of mattress production system in third quarter, 2020 25 Table 3 The Average Production Productivity Rate per day 26 Table 3.4 The demand forecast for 2023 27 Table List of machines and processing tables in the mattress production line 28 Table Table of processing time of machines and processing tables in the mattress production line 29 Table The output of mattress production line - the actual model 42 Table Detail state of all objects in the Cover Section – Actual simulation model 44 Table Detail Avg stay time and input/output quantity of all objects in the Cover Section – Actual simulation model 45 Table 10 Detail state of all objects in the Spring Section – Actual simulation model 47 Table 11 Detail Avg stay time and input/output quantity of all objects in the Spring Section – Actual simulation model 49 Table 12 Detail state of all objects in the Finishing Section – Actual simulation model 50 Table 13 Detail Avg stay time and input/output quantity of all objects in the Finishing Section – Actual simulation model 51 Table The output of mattress production line - Scenario1 simulation model 54 Table Detail state of all objects in the Cover Section – Scenario1 simulation model 56 Table Detail Avg stay time and input/output quantity of all objects in the Cover Section – Scenario1 simulation model 57 Table 4 Detail state of all objects in the Spring Section – Sncenario1 simulation model 59 Table Detail Avg stay time and input/output quantity of all objects in the Spring Section – Scenario1 simulation model 59 v Table Detail state of all objects in the Finishing Section – Scenario1 simulation model 61 Table Detail Avg stay time and input/output quantity of all objects in the Finishing Section – Scenario1 simulation model 62 Table The output of mattress production line - Scenario2 simulation model 64 Table Detail state of all objects in the Cover Section – Scenario2 simulation model 66 Table 10 Detail Avg stay time and input/output quantity of all objects in the Cover Section – Scenario2 simulation model 67 Table 11 Detail Avg stay time and input/output quantity of all objects in the Spring Section – Scenario2 simulation model 68 Table 12 Detail state of all objects in the Finishing Section – Scenario2 simulation model 70 Table 13 Detail Avg stay time and input/output quantity of all objects in the Finishing Section – Scenario2 simulation model 71 vi LIST OF FIGURES Figure Process of the research deployment Figure 1 Image of Dunlopillo Vietnam Ltd Figure Medium End (ME): DUN AUDREY N) MATT 200X180X25CM VN .6 Figure High End (HE): DUN FIRMREST LUXE MATT 205X193X25CM BS Figure Very High End (V-HE): DUN CORINA PRE MATT 200X160X35CM (N) Figure DUN LATEX WORLD PURE MATT 200X160X20CM Figure Factory Organization Chart Figure Volume and variety characteristics for each process type 10 Figure 2 The volume – variety characteristics influence the manufacturing layout 12 Figure The relationship between manufacturing process types and basic layout types 14 Figure A logo image of Flexsim software 20 Figure Mattress production process 24 Figure 2D Layout drawing of Spring Section 30 Figure 3 2D Layout drawing of Cover Section 31 Figure 2D Layout drawing of Finishing Section 31 Figure 3D Logic model of Glue – box station 33 Figure Setup of the Glue-box table 4’s properties for 3D Logic model 33 Figure Setup of the PU Sheet queue’s properties for 3D Logic model .34 Figure Process flow for activities at Glue-box station 35 Figure Setup parameters for Process Flow Properties 35 Figure 10 3D model of process flow for Glue – box station 36 Figure 11 Setup parameters for Source Quilting Top 37 Figure 12 Setup parameters for Quilting Top machine 38 Figure 13 The complete existing 3D model of mattress production line 38 Figure 14 All of process flows for the logic model 40 vii 66 Table 10 Detail Avg stay time and input/output quantity of all objects in the Cover Section – Scenario2 simulation model No Name of Object Source quilting Top Quilting Top Quilted Top - Queue Quilted Top - Queue Hemming Top Hemmed Top - Queue Sewing Top Sewing Top Sewed Top – Queue 10 11 12 Source Bottom & Border Quilting Bottom & Border Quilted Bottom - Queue 13 Quilted Bottom - Queue 14 Hemming Bottom 15 Hemmed Bottom - Queue 16 17 Sewing Bottom Sewed Bottom - Queue 18 Quilted Border - Queue 19 Cutting 20 Cut Border - Queue 21 22 Hemming Border Hemmed Border - Queue 23 Embroidery 24 Embroidered Border - Queue 25 Sewing join 27 Joined Border 28 29 31 Sewing label Sewing label Sewed label Border 32 QC Cover 33 QC Cover Source: Exported from the Scenario2 simulation model – Flexsim 2019 67 In Spring Section: Everything in Spring Section is unchanged from the previous Scenario except for the appearance of the Combiner IPS2 so that I just concentrate on this change Through the Table 4.11, the Avg stay time of Coiled IPS on Queue is reduced from 752 minutes to 344,5 minutes and the output of IPS Spring is also increased by 14 units per day (from 45 to 59 units) Therefore, it makes the operation of this Section more effective and creates more springs to meet the demand Figure 11 Bar chart of Spring Section – Scenario2 simulation model Source: Exported from the Scenario2 simulation model – Flexsim 2019 Table 11 Detail Avg stay time and input/output quantity of all objects in the Spring Section – Scenario2 simulation model No Name of Queue Source BN BN Coiler Coiled BN – Queue Assemble BN Assembled BN – Queue Clip & Bend Clip & Bend BN Spring Unit - Queue Source CPS CPS Coiler 10 Coiled CPS - Queue 11 12 13 14 15 16 17 18 19 20 Fold Nonwoven Folded CPS - Queue Assemble CPS CPS Spring Unit - Queue Source IPS IPS Coiler Coiled IPS - Queue Combiner IPS Combiner IPS IPS Spring Unit - Queue Source: Exported from the Scenario2 simulation model – Flexsim 2019 In Finishing Section: Base on the Figure 4.12 and Table 4.12, there is only the state of Tape2 and Tape4 machine different from the Scenario1 Both machines reduce significantly their idle time (from 32.7% to 20.1%, 31.2% to 17.6% respectively) due to the increase of IPS Spring It can be seen that the Finishing Section can work continuously Figure 12 Pie chart of Finishing Section– Scenario2 simulation model Source: Exported from the Scenario2 simulation model – Flexsim 2019 69 Table 12 Detail state of all objects in the Finishing Section – Scenario2 simulation model No Name of Machine Glue box table Glue box table Glue box table Glue box table Tape Tape Source: Exported from the Scenario2 simulation model – Flexsim 2019 Moreover, by using overtime, Tape4 machines, and Glued – Table4 can make more Glued IPS, from 45 to 58 pcs which is more than the quantity of forecasting demand i.e 56 pcs, as shown in Table 4.13 Besides, Avg stay time of Glued IPS and Checked mattress is increased by 36,5 and 39,3 minutes due to the rise of Duchess mattress quantity However, the Scenario2 still can handle well these semi products on Queue and finished goods per day increase by 13 pcs from 214 to 227 Figure Bar chart of Finishing Section– Scenario2 simulation model Source: Exported from the Scenario2 simulation model – Flexsim 2019 70 Table 13 Detail Avg stay time and input/output quantity of all objects in the Finishing Section – Scenario2 simulation model No Name of Queue Glue Table Glued Bonnel - Queue Glue Table Glued Bonnel - Queue Tape Conveyor BN - Queue Glue Table Glued CPS - Queue Tape 10 Conveyor CPS - Queue 11 Glue Table 12 Glued IPS – Queue 13 Tape 14 Conveyor IPS - Queue 15 Tape 16 Conveyor BN - Queue 17 QC Finished Mattress 18 QC Finished Mattress 19 Checked Mattress 20 Packaging 21 Duchess Top 22 Duchess Bottom 23 Duchess Border 24 Marilyn Top 25 Marilyn Bottom 26 Marilyn Border 27 Contract Top 28 Contract Bottom 29 Contract Border Source: Exported from the Scenario2 simulation model – Flexsim 2019 71 CONCLUSION By using Flexsim simulation software version 2019 for this study and all solutions are pointed out in two Scenarios, the mattress production line is improved both efficiency of machines and the quantity of finished mattresses leading to the future demand covered Therefore, the thesis achieved the objectives stated Based on the statistic results from Scenarios, the quantity of finished mattresses improves significantly from 141 to 227 pcs per day which is approximately increased 61% Specially, the Scenario1 plays an important role in the increase by solving bottlenecks and utilizing all the current resources That is:  Adding more Clip – bend processing table helps the Bonnel Spring increase 20% (from 103 to 123 units) leading to Glue – Box1 & Glue - Box2 working more efficiently with no idle time (Reduce from 10,3% and 9,5% to 0, respectively), and the Avg stay time of Assembled Bonnel on Queue is reduced by 228,4 minutes (from 315,6 to 87,2 minutes)  Changing the task of Tape2 machine from Tape-edge Bonnel to IPS mattress: Tape1 machine is utilized more effectively whose idle time is reduced from 62% to 7,1% The idle time of Tape2 machine also decreases from 62,8% to 32,7%  Working overtime at Sewing Top and Bottom station and adding one more shift for Packaging help solve all the semi – mattress waiting on Queue Additionally, the Scenario2 also contributes the enhancement of finished mattress quantity by increasing the capability of Duchess mattress production to meet the forecasting demand:  Adding one more Combiner IPS processing table makes the number of IPS Spring units rise from 45 to 59 unit  Working overtime at Glue – Box4, Tape and at Sewing Top & Bottom station: Duchess mattress numbers reach 58 pcs a day from 45 pcs in the Scenario1 contributing to the overall increase of Finished mattresses i.e 227 pcs In general, based on the objectives and principles of low cost and output increase, the improvements and changes that have been suggested in the thesis are quite easy to 72 follow, and the cost for application is reasonable because existing machines are utilized more efficiently, and the added parts are semi-automatic machine and manual processing table which are not expensive to invest Besides, the proposed solutions still have limitation The first one is the constant overtime usage at Sewing Top & Bottom station, Glue – Box4, Tape4 machine and Clip – Bend2 Although overtime has a lot advantages such as reducing the cost of training new employees, creating more jobs to increase incomes for employees, stabilizing human resources However, using overtime in continuous time will lead to consequences such as reducing productivity because of worker’s health decline and high overtime costs That's why this needs to be considered more carefully to solve it satisfactorily The second limitation is long time consuming It took more than months since the idea has been raised until the study is completed The third one is the lack of modeller’s experience and skills so that the quality of the analysis may not be completely accurate, it needs more assessment from specialist to make sure the result of this study valuable 73 REFERENCES Công Thương (19/10/2020) Cuộc đua cạnh tranh thị trường nệm Retrieved from: https://congthuong.vn/cuoc-dua-canh-tranh-tren-thi-truong-nem-126957.html Axelrod, R (1997) Advancing the Art of Simulation in the Social Sciences Simulating Social Phenomena, 21–40 doi:10.1007/978-3-662-03366-1_2 Banks, J (Ed.) 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