s 1 design and dynamic control of a production line · murat fadıloğlu sinem Özkan company...
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Design and Dynamic Control
of a Production Line
Project Team
Aslıgül Börühan
Ayşe Doğan
Ayşe Melis Gökkan
Ceren Yeni
Yazgül Yurğun
Advisors
Murat Fadıloğlu
Sinem Özkan
Company Advisor
Seçkin Menteş
Established in 1978, located in Çiğli
Teknik Balans
Workforce of 80 employees
Industrial balancing machines,
automative service and garage equipments
Symptoms
● Inefficient organization of work space
● Poor layout
● Delays in satisfying customer demand
Problem
● Inefficiency throughout the process
4 different types of wheel balancing machines on the production line
Pull production system with no stock
Assembly Line Balancing (ALB) andProduct Sequencing to
Minimize cost and production time Increase productivity
• Large number of tasks • Long production lead times • High variability between production times
● Insufficient production capacity
Solution Methodology
Heuristic Method TARGET 14 Model 1 products per day
8 working hours – 1 hour¹ = 7 hours
7 hours/14 units= 0.5 hour/unit²
125 min³ 30 min/station= 5 stations
¹Two breaks and a lunch time
²Every 30 minutes a product should be manufactured
³Production time of the fastest model
● Kilbrage- Westers Algorithm is used to assign tasks.
Mathematical Programming Method
● LINGO’s optimal solution, identical to the result of our heuristic
Innovatively using buffer stocks to reduce
the damage due to process time variability in
mixed model lines!
Obtained fromLINGO Software
2x
Mo
de
ls
Cycle Time in Minutes
M4* (Slowest Product) M1* (Fastest Product)
•According to a generated scenario for
showing the usage of buffer stocks
Validation & Verification of the Solution
Parameters:
Model Formulation
N = Total number of tasks in the problem S = Number of stations 𝑃𝑅𝑘 = Subset of all tasks that precede task k, k=1,…,N 𝐷𝑘 = Performance time of task k, k=1,… ,N
𝑉𝑘𝑠 = 1, if task k is assgined to station s
0, otherwise
𝐴𝑘𝑠 = 1, if station s is utilized
0, otherwise
Decision Variables:
𝑠=1
𝑆
𝑉𝑘𝑠 = 1 for 𝑘 = 1 ,… , 𝑁
𝑉𝑘𝑠 ∈ 0 , 1 ; 𝐴𝑠∈ 0 , 1
Min
𝑠=1
𝑆
𝑠 . 𝑉𝑙𝑠 ≤
𝑠=1
𝑆
𝑠. 𝑉𝑘𝑠
𝑘=1
𝑁
𝐷𝑘 . 𝑉𝑘𝑠 ≤ 𝐴𝑠. 𝐶𝑦𝑐𝑙𝑒𝑇𝑖𝑚𝑒 ∀𝑠 = 1, … , 𝑆
∀k=1,..,N; 𝑙 ∈ 𝑃𝑅𝑘
𝑠=1
𝑆
𝐴𝑠
𝑠=1
𝑆
𝑉𝑘𝑠 = 1 for 𝑘 = 1 ,… , 𝑁
𝑉𝑘𝑠 ∈ 0 , 1 ; 𝐴𝑠∈ 0 , 1
Min CycleTime
𝑠=1
𝑆
𝑠 . 𝑉𝑙𝑠 ≤
𝑠=1
𝑆
𝑠. 𝑉𝑘𝑠
𝑘=1
𝑁
𝐷𝑘 . 𝑉𝑘𝑠 ≤ CycleTime ∀𝑠 = 1, … , 𝑆
∀ k = 1,..,N ;𝑙 ∈ 𝑃𝑅𝑘
(1.1)
(1.5)
(1.4)
(1.3)
(1.2)
(2.1)
(2.5)
(2.4)
(2.3)
(2.2)
(1.1) Objective function for solving the ALB Type 1 Problem (minimizing number of workstations)
(2.1) Objective function for solving the ALB Type 2 Problem (minimizing cycle time)
(1.2) & (2.2) Assignment Constraints
(1.3) & (2.3) Precedence Constraints
(1.4) Cycle Time Constraint for a given Cycle Time
(2.4) Cycle Time Constraint for given number of workstations
(1.5) & (2.5) Binary variable values
Bricker D. L. and S. H. Juang (1993), “A Mathematical Programming
Model of the Assembly Line Balancing Problem”
Das S. K, C. Jaturanonda and S. Nanthavanij (2013), “Heuristic
Procedure for the Assembly Line Balancing Problem With Postural Load
Smoothness,” International Journal of Occupational Safety and
Ergonomics 19 ,531–541.
Literature Review
Kilbridge, M. D., & Wester, L. A Heuristic Method of Assembly Line
Balancing. The Journal of Industrial Engineering, 12(4), 292-298, (1961).
Mendes, A.R., Ramos, A.L., Simaria, A.S. and Vilarinho, P.M. (2005).
Combining Heuristic Procedures and Simulation Models for Balancing A PC
Camera Assembly Line, Computers & Industrial Engineering, 49, 413-431.
How did we achieve it?
Capacity of the line is 17
Model 1 products per day
Reducing the wastes [rework, waiting in queues,
lateness, keeping stock, idle time etc.]
Improving processes
Increasing the utilization
Better layout and material flows
Dynamic schedule
Reducing the effects of changeovers
Maximum ThroughputMinimum Cycle Time
Production Time in Old System
Production Time in Improved System
Model 1 230 min 125 min
Model 2 255 min 134 min
Model 3 296 min 153 min
Model 4 386 min 214 min
100120140160180200220240
0 10 20 30
Pro
du
cti
on
Tim
e
Scheduled Products
M4* (Slowest Product) M1* (Fastest Product)
Worker
Utilizations
Worker 1
98%
Worker 2
99%Worker 3
98%
Worker 4
99%Worker 5
87%
Comparison and Quantification of Improvements
85% INCREASE
IN PRODUCTION
CAPACITY!
Applicability of Proposed Approach
Choice of buffer size is justified!
Dynamic controlof the system withstate variables
13PRODUCTS IN A DAY
Decision Support System
has the flexibility of adding a
new model and changing the
operation descriptions
updates itself according to the
new data
gives the daily schedule
enables to see the process
details and recorded errors
creates a database
Design of the Line
Standard Job Description
Forms
Ön etiket yapıştırılır
Etiket
Temizleyici
Sünger
Sünger ile üstünden geçilir Sünger
Ön etiket alanı ölçülürMetre
Kalem
İş Tanımı Sirion Serisi Sabit Balans Makinası Üretim Hattı
Güvenlik Ekipmanları
Operasyon Tanımı Opeasyon Resmi Gerekli
MalzemelerGerekli Araçlar Uyarılar
NOTLAR
Ürün Modeli Sirion Pro-Sİstasyon
Numarası1
Arka uyarı etiket yapıştırılır
Arka uyarı etiketinin altına Mess
Matic etiketi yapıştırılır
Arka etiketler için ölçüm sacı takılrÖlçüm sacı
Etiketler
Etiketler
Etiketler
Etiketler230 V etiketi yapışıtırılır
TEKNİK BALANS STANDART İŞ FORMU
can be used for educationalpurposes
helps standardize tasks