Development of Production Layout Model to Improve Production Efficiency

Transcription

1 Development of Production Layout Model to Improve Production Efficiency A. R. AB Kadir, W.M.K.Sajidah, C.A. Mohd Norzaimi, K. Shahril, and M. Sabri, Universiti Kuala Lumpur Malaysian Spanish Institute, Kulim Hi-Tech Park, Kulim, Kedah, Malaysia. Department of Manufacturing Section, Universiti Kuala Lumpur Malaysian Spanish Institute, Kulim Hi-Tech Park, Kulim, Kedah, Malaysia. and Abstract In all manufacturing industries the layout of facilities arrangement as key decision that will determinant of long-run of operation efficiency in term of production output. Whenever the flow of material or people is complex, alternative approaches for facilities design offer feasible means of developing and evaluating alternative arrangement. The primary goals of this present paper focus on identification production efficiency of current Front of Line production layout model by analyzing the effectiveness of existing production layout model at selected case study. A time study technique is presented as methodology that includes the evaluated of effectiveness and performance of current production layout by using mathematical calculation based on takt time and production target. The level of production layout performance shown that the production efficiency affected by bottleneck occurrence at improper sequencing in production flow. Result shown that the capacity of the bottleneck workstation not equal to the capacity of actual production line. It conclude that, evaluating efficiency in production layout depends on obtain the necessary of production quantity that always meet customer demands with fewest labour hours of production line in the best takt time. Therefore, the possible waste in bottleneck should be minimize by apply lean production in proposed new production layout model because it severely affects the productivity and increase the labour hour of production line. Keywords Facilities Layout, Time Study, Lean Production I. INTRODUCTION In modern manufacturing system, layout design is the main goals that will maximization of productivity of manufacturing process. This depends on several factors such as the type of product made, the quality of raw material, the technique of manufacturing process and the arrangement of workstation contribute to production line. The challenge in determining the best solution arrangement of the workstation is one of the elements that will make huge change on the manufacturing system performance. The production layout also knows as facility layout that includes planning location, process flow, floor layout and material handling system. The objective each manufacturing industry is to ensure the smooth and efficient of the production process from the first stage of material until the end of the process based on the production layout design that will reduce the waste activities in production line and improve the overall effectiveness in the production.. Facility layout has being a significant contributor to manufacturing performance, has been studied many times over the past decades. (Tompkins et al 1996) was concluding that a good placement of facilities will contribute to the overall efficiency of operation and can reduce until 50% of the total operating expenses. (There, 1964) also state that the good placement of facilities will reduce about 20% to 50% of the total operating expenses in term of reduction costs by 10% to 30% annually in material handling costs in manufacturing industry. The previous literature gives that a facility layout is an arrangement of everything needed for production of good or delivery of services. A facility is an entity that facilitates the performance of any job. It may be machine tool, a work centre, a manufacturing cell, a machine shop, a department, a warehouse, etc. (Amine Drira et al, 2007). In manufactuirng industy, there are two main problems that need to be considering for the production layout (Sahin et al, 2009). The first one is the quantitative approach aiming at minimizing the total material handling cost between workstation based on a distance function. Secondly is the approach aiming at minimizing the waste activities or nonvalue added activities in production line. Material handling and process flow have close relationship in production line. Worker and material have to travel along distance from first stage of raw material until final stage of finish product in manufacturing process; the material handling system with low level of automated handling will effect the production efficiency regarding to manual handling among of worker uncapable to be control compared to automated handling such as conveyors, automated guided vehicles, pallet and other. Generally, in manufacturing system, there are four main type of layout which is; fixed position layout, process layout, product layout and cellular layout (Dilworth, 1996). Fixed position layout concept from the other three, with material brought to the workstation. It is used in aircraft assembly, shipbuilding and heavy machinery. Process layout obtained machines of a similar type are arranged together at 261

2 one place. Normally, process layout was applied in toy factory and hospital. Product layout was based on This used for the realization of one product in high volume of production and low variety of product such as in this research, the machines and equipment arranged in line and the product one focus on one type which is LPG cylinder gas. Finally, the cellular layout allocates dissimilar machines into cells to work on products that have similar shapes and processing requirements. For example; metal fabricating, computer chip manufacture, and assembly work. In contrast, the study by (Kuok, Siah, & Tay, n.d.) (Jiang & Nee, 2013) were indicating that the similarity in objective which is design the factory layout to located a physical arrangement that most economically achieves the required output quantity and quality. It will result the effectiveness and efficiency of factory performance in production process. Which the same objective, the literature conducted the floor layout planning by improvement of several output which are; process and work flow, proper allocation of space and resources, easier to supplies and material, product efficiency, and maximize the space utilization. In a different study, (Dwijayanti, Dawal, & Aoyama, 2010) analyze that facility layout design determine to arrange, located and distribute the equipment and support services in a manufacturing facility to achieve minimization of overall production time; maximization of operational and arrangement flexibility, maximization of turnover of work-in process (WIP) and maximization of factory output in conformance with production schedules. Lean manufacturing also known as lean production has been one of the most popular paradigms in waste elimination in the manufacturing and service industry. At the same time, lean manufacturing similar know as methodologies that have the systematic approach to process improvement in planning the process flow. This method was based on finding and reducing waste coupled by applied continuous improvement in production system. It was first develop Toyota (the Japanese car manufacturer), and gained ground as a best practice has now been applied to many diverse industries and business in manufacturing strategy. Lean production consist of several manufacturing practice which is process focus, pull production, quality development, total productive maintenance, continuous improvement, worker empowerment, supplier development and more. The main objective of lean production is to satisfy customer needs on the highest possible level through the elimination waste. There are seven type of waste in lean production which includes; overproduction, waiting time, movement, transportation, inventory, over processing and defects (Art of Lean, n.d.). A few research has gave insight on how manufacturing companies carried out their lean journey in production process to improve machines and equipments are arranged in one line depend the sequence of operations required for the product. productivity with continual improvement. This papers was focus on the production layout which is same with the current layout of the cell because of the space available, the machines, the equipment and the process flow is suitable for this type of layout. Generally, in production layout the machines and equipment are arranged in single line depends on sequence of process acitivity required for the product in manufacturing system. The material in production layout typically flow from one workstations directly to the next workstation. The product in production layout usually in high-volume of production and low variety of product. It means that, manufacturing industry that having production layout only focusing on minimum variety of product but highly volume of production in one day depends on highly demand from user. The current production layout represented in figure 2 as a main reference to development of the production layout As a case study in this paper, the company has been selected to perform the verification and validation the production layout performance in term of improvement production efficiency. This company provides refurbishment services for liquefied petroleum gas (LPG) cylinder in accordance to the specification and requirement of our valued customer. The company vision is to be globally high reputation and competitive company for manufacturing and supplying oil and gas related products and services. The company mission is to deliver Oil & Gas Related products and services of the highest quality, efficiency and safety. Continuously monitor and improvement of Quality System was applied in working culture in organization. Fig.2: Production Layout of refurbishment services for liquefied petroleum gas (LPG) cylinder 261

3 II. METHODOLOGY A. Judgement Condition Analysis/Production Layout In this section, is representing the identification on the actual layout practise was done about one and half month at the compony. Fig. 3 was demonstrate the summarize layout problem in FOL. In recent years, there has been an increasing amount of literature research on facility layout problem. The detailed in layout problem includes flow line layout problem, machine layout problem and cellular manufacturing design problem, where machines are assumed to be of equal area or of fixed dimension (R. D. Meller & Gau, 1996). It is more to space utilization that have similarity defined by (Liggett, 2000) layout problem exist when design and allocation of space in a new building or the reassignment of space in an existing building. (Shayan * & Chittilappilly, 2004) argue that, the facility layout problem as the determination of the relative location for and allocation of the available space among a given number of facilities. In another study, (Khan, Tidke, & Scholar, 2013) examined that layout problem regarding the functional arrangement of department, machines, equipment and services in a manufacturing will maximize the capacity of space and increase cost of layout design. A number of studies was found that facility layout problem concerned when finding the most efficient production line in term of arrangement of facilities needed in manufacturing industry that consider the space requirement, material handling system, material flow, overlapping placement and etc that will impact the layout design (N. and V. Meller, 1999). B Time Study Fig. 3: Summarize of current production layout There was having mathematical calculation of time study in manufacturing facilities design. Before understand the importance use of time study, research must understand what the term of time standard means. A time standard is defined as the time required to produce a product at a workstation with the following three conditions: a qualified, well-trained operator; working at a normal pace; and doing a specific task. The table 1 was clearly explained on the meaning of three conditions in time standard that was applied in this methodology. TABLE 1:TIME STANDARD CONDITION Condition of Definition Example Time Standard Experience was In production flow, the when usually what less of manual makes a qualified, equipment required long well-trained learning period. The A qualified, welltrained operator operator, and time on the job was the best indication of mistake mode by new time study personnel is time studying someone experience. The too soon due to different Normal pace Specific task time needed to become qualified varies with the job and the person. Experience was when usually what makes a qualified, well-trained operator, and time on the job was the best indication of experience. The time needed to become qualified varies with the job and the person. The description of the specific task must include; 1. The prescribed work method. 2. The material specification. 3. The tools and equipment being used. 4. The position of incoming and outgoing material. 5. Additional requirements such as safety, quality, housekeeping, and maintenance tasks. qualified, well-trained operators in handling their job. In production flow, the process that involves in the degassing station were; 1. Put five gas tester to LPG in 1.25 seconds 2. Collect 2 LPG in 3.47 seconds. 3. Moving of 2 LPG in 1.73 seconds. In this situation, normal time was done by senior operator, the normal time will cause different results when trained operator done this tasks due to carried two LPG in single movement will take time to trained operator to comfortable with the load carried. In production flow, the prescribed work from starting FOL to ship the conveyer station was limited of the tool and equipment due to worker need to move from one station to next station by walking with carried 2 LPG by manually and the distance between unloading stations to next station was too far. In this case, the additional requirement such as applied of 5s housekeeping after donning process in each station. 262

4 Time Study Procedure Step 1: Select the job to study. In production layout, the job to study refer to the all job that need to be complete in FOL production layout as Figure 4 the job need to be study which are Degassing, Decanting, Devalving, Shot Blasting, QC Inspection, Hydrostatic, Stamping, and Welding. The job unloading LPG and Ship to conveyer consider as offline station. This step refer to the essence of the stopwatch time study, the cycle time in Table 2 was record in 5 times of trial for every elements that state in step 3 for every standard operating procedure done by worker in every station. All the cycle time recorded in Table 2 was calculated their average of cycle time and the average cycle time was added fatigue allowance to make the time followed the standard practical. All calculation in this step was calculated by using formula; (1) (2) (4) Step 5: Selection workstation for extend the time study From data collection of cycle time in FOL production layout, there were only 6 workstation was selected to extend the time study, due to operating the 6 workstation working on daily production of FOL. The summarize data for extend time study in Table 3. Fig.4: FOL process flow. Step 2: Collect information about the job. The information that regarding to job selection at first step such as working hour per day, working shift, working procedure each job, cycle time each procedure, number of operator, daily output target. These all information will relate each other and will used to mathematical calculation in next coming step of time study. Working hour = 8 hours per day ( 45minutes break) Working hour available = 7.25 hours per shift Working shift = 2 shift per day Available operator = 11 person for 8 workstation Working procedure and cycle time in table 3.2 Daily production target = 1000 units Step 3: Divide the job into elements. An element in this step refers to the process or movement of LPG that divide into different job at different workstation from collection of information in step 2 in Table 2. Step 4: Do the actual time study. Step 6: Analyze data of table 3 The data was analyzing, to obtain the time necessary for carrying out the job performance at a defined level of performance in term of production output and number of worker. In this step the calculation, the longest cycle time was selected to further calculation by using formula; The time study method was to obtain the time necessary for carrying out the job at different level of performance to improve production output and to indentify the first objective by apply time study. The further method will need to complete the time study approach in this research. (5) (6) (7) (8) (9) 263

5 C. Modelling the FOL production layout through Critical Path Method. Generally, CPM was a project management technique that will also for modelling of existing layout design in phase 2 workflow in this research methodology. It will further studies during next research to proposed the new production layout of FOL. The planning of basic step for modelling FOL by applies CPM methods; Step 1: Define the project and prepared the work breakdown structure. The process flow on FOL production layout was defined in figure 4. Step 2: Develop the relationship among the activities in FOL production. The activities will decide by precedence and which follow each other. Step 3: Draw the network connecting all the activities. Step 4: Assign time estimate to each activity. Step 5: Compute the longest time path through the network. This was called the critical path. Step 6: Apply the network to help plan, schedule and arrangement of the process flow. After, the 6 basic step done in CPM method the proposed new production layout for case study will be further with the next method to complete the research objective which to improve production efficiency in production layout. D. Witness Simulation (Waller, 2012) was introduced that WITNESS was a software package with pedigree and has been successfully used by thousand of models over the past 20 years. It was group with modern software development platform and interfaced design as witnesses by Lanner s Microsoft Gold Partner status and Window 7. WITNESS simulation software was selected for this study as fourth methodology of development the model of production layout to improve production efficiency. In detail, this software will used to conduct simulation experiments to achieve the third objective in this study which are verification and validation model of FOL production layout. This methodology will start by following procedure; Step 1: Modelling the conceptual model of the FOL model. Input Parameters Set-up Time Machine Orientation Shifts Orientation Perform ance from different Fig..5: Conceptual Model of the FOL model Step 2: Develop the Simulation Model. Output Parameters Production efficiency Cycle time Eliminate waste Step 3: Run the Simulation Model for each possible model of FOL in previous step. Step 4: Statistical Analysis for the result of simulation model. Step 5: Verification and validation of model FOL production layout. Step 6: Validation for final results of selected model FOL production layout. The verification and validation of production layout model in this research study will more used WITNESS simulation to built and test the model to find the best arrangement of production layout. Therefore, the objective this research will achieve by using suitable method. III. RESULTS & DISCUSSION Based on table 3 the cycle time and number of worker between workstation in front of line layout are having different time in second due to different work activities and number of worker. The total number of worker in Table 3 can be defined as the actual practice in FOL layout. The result on the number of worker by using formula (9) in time study technique is equal to 4.7 persons. Therefore, the manufacture should be minimizing the number of worker to balance the cycle time between workstation. Further result is represented in graph 1. TABLE 3: CYCLE TIME AND NUMBER OR WORKERS IN FRONT OF LINE WORKSTATION. NO WORKSTATION CYCLE WORKER TIME (SEC) (person) 1 Degassing Devalving Shot Blasting QC Inspection Hydrostatic Stamping TOTAL

6 The result of the case study also represented in graph 1 based on the mathematical calculation on time study technique. The cycle time between workstation shown that the three stations are working over takt time which is 52.2 sec that represent in red line in graph 1. In production, takt time means time taken of one product should be manufactured in a given number of minutes and second based on time available for manufactured for the same period of time and customer requirements for a period of time for example, in case study the manufactured should meet the customer requirement in 1000 units of LPG in daily production. From the result of cycle time, the longest cycle time goes to QC inspection station. It means that, the bottleneck problem was having in this production line when the longest cycle time of workstation was given smallest unit per hours which is 50 units for the calculation of formula (5) in time study. The comparison between actual production outputs has been study to evaluate the production efficiency of current layout practice in case study. The capacity actual process should be equal to capacity at bottleneck but based on time study calculation technique result shown that the capacity at bottleneck equal to 725 units while the capacity of actual process at case study equal to 616.units. Therefore, the capacity between bottleneck station and actual production are not equal. Graph 1: Cycle time of workstation in Front of Line layout There were possible roots causes of bottleneck occurrence in production line. It can be one of the major problems by most SMEs in manufacturing parts that necessitate machining operation. The bottleneck was occurrence mainly due to improper sequencing at facilities within the work area. It means that, the actual layout practice in case study need to development to improve the production efficiency. The comparison of the production efficiency was shown in Graph 2 from the case study data collection and time study calculation. Graph 2: Monthly Production Schedule of 2014 In Graph 2, the comparison production in monthly between customer demand, STIC target and actual output represent in bar chart. While in purple line with markers refer to production efficiency by calculation of percentages between actual outputs over STIC target. From the graph 2, the actual output going up and going down not consistently with the target and customer demand. When the actual output not consistent the percentages of the production efficiency will interrupt due to change. IV. CONCLUSION In order to evaluating efficiency, the key factor is the necessary of production quantity based on consideration of how the necessary items can be manufactured with fewest labor hours possible in the best time. It means that, manufactured need to planning the available time of items to meet customer demand to avoid the buffer in takt time. Therefore, the best arrangement of production layout should be develop to avoid the bottleneck problem and to increase production efficiency. The production efficiency related with production schedule, customer demand and takt time. For the further study, this paper will continue in modeling the production layout through critical path method (CPM) and Witness simulation to verification the layout design before practice in actual case study. The bottleneck problem can be as a waste in lean manufacturing that need to eliminate or reduced the root caused to improve the production layout with waste in production line and apply the lean principle in manufacturing company. ACKNOWLEDGEMENTS This worked supported by Univertsity Kuala Lumpur for providing support, encouragement, and for lending me the opportunity to do this project and also thank to the faculty at Manufacturing Department and staff of Star Technology Corporation for providing a family-oriented work environment. 265

7 REFERENCES [1] Art of Lean. (n.d.). Toyota Production System Basic Handbook, Retrieved from [2] Dilworth, J.. (1996). OPERATION MANAGEMENT. [3] Dwijayanti, K., Dawal, S. Z. M., & Aoyama, H. (2010). A Proposed Study on Facility Planning and Design in Manufacturing Process. Proceedings of the International MultiConference of Engineers and Computer Scientists, III(IMECS 2010,Hongkong), 1 6. [4] Hasan, M. A., Sarkis, J., & Shankar, R. (2012). Agility and production flow layouts: An analytical decision analysis. Computers and Industrial Engineering, 62(4), [5] J, A. TOMPKINS, J, A. WHITE, Y, A. BOZER, J, M, S. T. (1996). Facilities Planning (Third). John Wiley & Sonc, Inc. [6] Jiang, S., & Nee, a. Y. C. (2013). A novel facility layout planning and optimization methodology. CIRP Annals - Manufacturing Technology, 62(1), [7] Khan, A. J., Tidke, D. J., & Scholar, M. T. (2013). Designing Facilities Layout for Small and Medium Enterprises, 1(2). [8] Kuok, A., Siah, L., & Tay, Y. H. (n.d.). Optimization Modeling for Factory Floor Planning. Citeseer, (M), 1 6. Retrieved from p;rep=rep1&type=pdf [9] Liggett, R. S. (2000). Automated facilities layout: Past, present and future. Automation in Construction, 9(2), [10] Meller, N. and V. (1999). Optimal facility layout design. Operations Research Letters, 23(3 5), [11] Meller, R. D., & Gau, K. Y. (1996). The facility layout problem: Recent and emerging trends and perspectives. Journal of Manufacturing Systems, 15(5), [12] Shayan *, E., & Chittilappilly, A. (2004). Genetic algorithm for facilities layout problems based on slicing tree structure. International Journal of Production Research. [13] There, L. (1964). Facility Layout, 1 8. [14] Waller, A. (2012). WITNESS Simulation Software. Proceedings of the 2012 Winter Simulation Conference,