International Journal of Modern Research in Engineering & Management (IJMREM) ||Volume|| 2 ||Issue|| 8 ||Pages|| 11-18 || August 2019 || ISSN: 2581-4540
Designing Production Flow Line using Heuristic Techniques: A Case Study at Zeal Pak Cement Factory Ltd, Hyderabad 1, 1,2,
Yasir Hashmi, 2, Prof. Dr. Abdul Salaam Soomro, 3, Hammad Hashmi
Department of Industrial Engineering and management, MUET Jamshoro, Sindh, 3, Department of Energy & Environment Engineering, QUEST Nawabshah, Sindh
-------------------------------------------------------ABSTRACT--------------------------------------------------Heuristics play a vital role in our daily life specifically in production and manufacturing sectors where organizations strive to extract maximum output from their systems, in this research work flowline of a cement factory has been redesigned using Ranked Positional Weight method in order to get more efficient system. To achieve most effective flowline various efforts have been made in rearranging the tasks and workstations. Results shown that Ranked positional weight method does not guarantee an optimized flowline but it enables us to make a better understanding regarding time consumption at each task, which can be arranged in a suitable manner to provide maximum output.
KEYWORDS: Ranked Positional Weight, Heuristics, Line balancing, Production, Management --------------------------------------------------------------------------------------------------------------------------------------Date of Submission: Date, 14 August 2019 Date of Publication: 28 August 2019 ---------------------------------------------------------------------------------------------------------------------------------------
I. INTRODUCTION Production activities in a manufacturing industry are closely related to the production flowline balancing. There are number of methods that are followed to balance flowline and remove bottle necking from system and enhance productivity [1]. This research work uses Heuristic technique to design production flowline, there are various methods within Heuristics, this research work is specifically based on Ranked Positional Weight technique. It has been stated by many researchers that Ranked Positional Weight method is most comprehensive and adaptable technique, it has never been applied on a cement industry [2]. This research work is done to validate the methodology of Heuristics and check the effectiveness of methodology. Various techniques of heuristics method are applied for sequencing and line balancing some of them are 1. Moodie-Young method 2. Killbridge and Wester Heuristic method 3. Hoffmans or Precedence Matrix method 4. Immediate Update First Fit method 5. Ranked Position Weighted method (RPW) [3]. Ranked positional Weight method is used for task assignment in cellular manufacturing for improvement in production, tasks are arranged in descending order of their positional weight [4]. Ranked Positional Weight method studies the cycle time of different work stations and predecessors. Zoning constraints are been accessed and tasks are rearranged according to their predecessors [5]. Ranked positional weight method has been practiced a lot because of its flexibility and adaptability in any type of industry [6]. Assembly line balancing is a typical work and if carried out properly can result in an increased output [7]. Ranked positional weight detects the unnecessary wastage in those industries where there are many tasks and there is a great possibility of time wastage and difficult to arrange [8]. Ranked Positional Weight not only detects the wastage, but it also shows us the major and minor tasks according to time consumption and idle time created by the arrangement of tasks [9]. It is found to be a very effective technique in assembly line balancing problems, such as gear box manufacturing or toy manufacturing factories which have lots of tasks in a flowline [10].
II. AIMS AND OBJECTIVES Aim of this study is to redesign flowline to achieve maximum production. Objectives of this study are: 1. To determine required number of workstations in ZPCFL for designing production flow line. 2. To assign tasks for each station in ZPCFL using Heuristics Technique for designing production line. 3. To suggest output rate or cycle time in ZPCFL based on the new designed production flow line
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Designing Production Flow Line using Heuristic Techniques‌ III. RESEARCH METHODOLOGY Research methodology follows a series of steps which are divides into three phases. A. Phase 1 (Existing Layout): 1. Number of workstations and tasks being performed in existing flowline. 2. Designing predecessor network diagram. 3. Cycle time calculation of all equipment 4. Efficiency calculation of existing flowline B. Phase 2 (Evaluating with Ranked Positional Weight method): 1. Calculation of positional weight of all tasks. 2. Arranging tasks in descending order 3. Assigning tasks to workstations according descending order of positional weight. 4. Efficiency calculation of flowline designed by ranked positional weight. C. Phase 3 (Redesign flowline to decrease cycle time) 1. Rearranging tasks to achieve less cycle time 2. Calculate efficiency of designed flowline
IV. DATA COLLECTION Installed capacity of all equipment have been used for designing production flowline. Data collected for various equipment have been discussed below. D. Cycle time: Cycle time is the time taken by an operation to produce a unit product. In this case cycle time is the time taken by each operation to produce one ton of cement. Cycle time of every operation is discussed below. 1) Crusher a) Crusher 1 (used for lime stone) 120 tons per day =722.4 sec per ton b) Crusher 2 (used for Graphite) 80 tons per day =1200 sec per ton 2) Mill House a) Raw mill 25 tons per hour = 144 sec per ton b) Cement Mill 31 tons per hour =116 sec per ton 3) Basin 400 tons per day = 216 sec per ton 4) Coal Plant 15 tons per hour = 240 sec per ton 5) Kiln 400 tons per day = 216 sec per ton
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Designing Production Flow Line using Heuristic Techniques‌ 6) Packing Plant 80 tons per hour = 45 sec per ton For three machines E. Existing Plant Layout If you Layout below represents the existing layout and sequence of operations in the flowline in discrete workstations shown with different colors.
Fig. 1. Existing plant layout Bar chart below shows the time consumption by each workstation of existing plant. Maximum time is consumed by 1st workstation and cycle time is 1800 sec.
1800 sec cycle time
Fig. 2. Time consumed by each workstation in existing layout
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Designing Production Flow Line using Heuristic Techniques… F. Line Efficiency Line Efficiency = (Total Station Line Time ÷ Cycle time x no. of workstations) x 100 Line Efficiency = (2747/ (1800 x 6)) x 100 Line Efficiency = 25.4 %
V. DATA ANALYSIS Before calculation of positional weight its necessary to find out predecessors and independent operations. Table. 1 shows predecessors and independent operations of whole flowline. TABLE 1. PREDECESSORS OF EACH TASK IN EXISTING FLOWLINE Task Number 1 2 3 4 5 6 7 8
Description of Task Quarrying (crushing of lime stone) Raw Milling (Addition of sand and clay and Grinding into fine particles) Mixing or Blending of slurry (Blending in large containers known as basin) Coal Grinding (Coal required for kiln as a burning agent or fuel) Kiln (Baking of slurry paste) Crushed graphite for addition in clinker Cement milling (Clinker is grinded with graphite and gypsum) Packing plant (packing of cement in paper bags)
Immediate Predecessors 1
Time for Task (Sec)
1,2
216
-
240
1,2,3,4 1,2,3,4,5,6
216 1080 116
1,2,3,4,5,6,7
15
720 144
Total:
2747
G. Positional Weight: Below table shows the calculation of positional weight of each operation TABLE 2. CALCULATION OF POSITIONAL WEIGHT OF EACH TASK Task Number 1 2 3 4 5 6 7 8
Task Time in seconds 720 144 216 240 216 1080 116 15
Solution for Positional Weight in seconds
Positional Weight
720+144+216+240+216+1080+116+15 144+216+240+216+1080+116+15 216+240+216+1080+116+15 240+216+1080+116+15 216+1080+116+15 1080+116+15 116+15 15
2747 2027 1883 1667 1427 1211 131 15
TABLE 3. RANKING OF POSITIONAL WEIGHTS Task Number 1 2 3 4 5 6 7 8
Task Time in Minutes 45.78 33.78 31.38 27.78 23.78 20.18 2.18 0.25
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Positional Weight 2747 2027 1883 1667 1427 1211 131 15
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Rank of Tasks in Descending Order of Positional Weight 1 2 3 4 5 6 7 8
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Designing Production Flow Line using Heuristic Techniques‌ H. Layout designed according to Ranked Positional Weight: Ranked Positional Weight method sorts the workstations in descending order of their positional weights. Unfortunately, all workstations are already arranged in descending order and workstations cannot be reduced due to zoning constraints. Possible arrangement of workstations by Ranked Positional Weight method has been shown in the figure below.
Fig. 3. Layout suggested by Ranked Positional Weight Bar chart below shows the time consumption by each workstation after arranging tasks by Ranked Positional Weight method. Maximum time is consumed by 1st workstation and cycle time is 1800 sec.
1800 sec cycle time
Fig. 4. Time consumed by each workstation in layout suggested by Ranked Positional Weight Line efficiency of layout based on Positional weight Line efficiency of flowline designed by Ranked Positional Weight is calculated below: Line Efficiency = (Total Station Line Time á Cycle time x no. of workstations) x 100 Line Efficiency = (2747/ (1800 x 6)) x 100 Line Efficiency = 25.4 %
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Designing Production Flow Line using Heuristic Techniques‌ Rearranging Tasks: Maximum time consumed in the layout suggested by Ranked Positional Weight method was by 1st workstation, having graphite crusher independent of any task. Hence to reduce cycle time graphite crusher is relocated near cement mill keeping in view the zoning constraints. Suggested layout has been described by the figure shown below
Fig. 5. Layout suggested by rearranging tasks Bar chart below shows that time consumed by 1st workstation has been reduced to 720 seconds leading to overall decrease in cycle time from 1800 seconds to 1196 seconds.
1196 sec cycle time
Fig. 6. Time consumed by each workstation in layout suggested by rearranging tasks Line efficiency of layout based on Rearranged tasks; By the help of line efficiency difference between all three flowlines of existing, Ranked Positional Weight and suggested flowline is clearly visible. Calculation of line efficiency of suggested layout is:
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Designing Production Flow Line using Heuristic Techniques… Line Efficiency = (Total Station Line Time ÷ Cycle time x no. of workstations) x 100 Line Efficiency = (2747 / (1196 x 6)) x 100 Line Efficiency = 38.28%
VI. RESULTS According to suggested layout number of workstations should remain 6. Tasks been assigned by suggested layout are mentioned in the table below: TABLE 4. WORKSTATIONS AND THEIR TASKS ASSIGNED IN SUGGESTED LAYOUT Workstation Workstation 1 Workstation 2 Workstation 3 Workstation 4 Workstation 5 Workstation 6
Task 1 Crusher 1 lime stone Raw mill Coal plant Kiln Crusher 2 graphite Packing Plant
Task 2 Basin
Cement mill
Line efficiency of existing layout is 25.4% at production of 300 tons per day. Line efficiency of layout based on Ranked Positional Weight is also 25.4%. By rearranging the tasks Efficiency obtained is 38.2% which will produce 450 tons per day. 1 bag of cement has a retail price of 560 PKR, 150 tons comprises of 800 bags, 800 bags have a cost of 16,80,000 PKR. By above designed flowline profit can be increased by 16,80,000 PKR per day.
VII. CONCLUSION Ranked Positional Weight method is a comprehensive and adaptable technique, but it does not guarantee to provide an increase in efficiency though it helps in sorting the flaws in system which helps in rectifying those issues. Efficient system has better utilization of resources and less consumption of fuel which is beneficial for both factory and environment.
VIII. ACKNOWLEDGEMENTS This research was conducted at Mehran University of Engineering and Technology, Jamshoro. First author of this research is highly acknowledged to the mutual co-operation of ZPCFL Hyderabad factory and supervisor Prof. Dr. Abdul Salam Soomro for improving readability of this paper.
REFERENCES A reference list MUST be included using the following information as a guide. Only cited text references are included. Each reference is referred to in the text by a number enclosed in a square bracket (i.e., [3]). References must be numbered and ordered according to where they are first mentioned in the paper, NOT alphabetically. Examples follow: Journal Papers: [1] Johan, H., Emil, S & Kristina, E., “A review of assembly line balancing and sequencing including line layouts”,University west Department of Engineering Science, Proceedings of PLANs, Volume 1, (3), pp86 Trollhattan, Sweden (2015). [2] Christian, B., Armin, S., “A survey on problem and methods in generalized assembly line balancing”, European, Operational Research,Volume 168,(2), pp. 694–715,Germany,September (2014). [3] Ponnambalam, S. G., Aravindan, P. &Naidu, G. M., “A Multi-Objective Genetic Algorithm for Solving Assembly Line Balancing Problem”.Advanced Manufacturing Technology.Volume 16,(6), pp 341-352 Springer -VerlagLondon Limited, India, (2016). [4] Minzu, V., and Henrioud,J. M., “Assignment stochastic algorithm in multi-product assembly lines,” Proceedings of ISATP’ Volume 37,(12), pp. 103-114,(1997). [5] Matondang,M. Z.,and Jambak,M. I., “Soft Computing in Optimizing Assembly Lines Balancing”, Computer Science, Volume 6 (8),pp 1549-3636 Science Publications, Malaysia (2010). [6] Ismail, N., Esmaeilian, G. R., Hamedi,M., and SulaimanS., “Balancing of parallel assembly lines with mixed-model product,” Management and Artificial Intelligence, Volume 6, (15), pp 120-124,
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Designing Production Flow Line using Heuristic Techniques… [7]
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ABOUT AUTHOR Student of Master’s in Industrial Engineering and Management at Mehran University of Engineering, Science and Technology Jamshoro. Graduated as Mechanical Engineer from Quaid-e-Awam university of Engineering, Science and Technology Nawabshah.
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