Operational improvement by leagile approach

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This research work is carried out in a air compressor manufacturing company which produces different models of air compressors. The work aim was to improve the productivity by reducing the total operating cycle time, unnecessary motions, material handling, and to create a standardized working environment.

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International Journal of Mechanical Engineering and Technology (IJMET) Volume 10, Issue 03, March 2019, pp.1025-1037. Article ID: IJMET_10_03_103 Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=10&IType=3 ISSN Print: 0976-6340 and ISSN Online: 0976-6359 © IAEME Publication Scopus Indexed OPERATIONAL IMPROVEMENT BY LEAGILE APPROACH Krishnamoorthy S Department of Mechanical Engineering, Sri Krishna College of Engineering and Technology Coimbatore, Tamilnadu, India. Ben Ruben R Department of Mechanical Engineering, Sri Krishna College of Engineering and Technology Coimbatore, Tamilnadu, India. ABSTRACT This research work is carried out in a air compressor manufacturing company which produces different models of air compressors. The work aim was to improve the productivity by reducing the total operating cycle time, unnecessary motions, material handling, and to create a standardized working environment. Two stations namely drive and lubrication assembly and testing were found out to be the bottleneck stations, and efforts are taken to improve its productivity. Kaizen’s were planned for improvement activities and were implemented subsequently. These improvement actions were based on Lean production organizational model and application of Lean tools. The current agility level of the firm was calculated and suggestions were given to improve the agility level of the firm. Keywords: Leagile, Testing, Kaizen, Agility Assessment, New Product Development. Cite this Article: Krishnamoorthy S and Ben Ruben R, Operational Improvement by Leagile Approach, International Journal of Mechanical Engineering and Technology, 10(3), 2019, pp. 1025-1037. http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=10&IType=3 1. INTRODUCTION Lean manufacturing is focused on eliminating wastes in the entire manufacturing process. It deals with minimizing work -in progress, eliminating processes that do not add value to the product, making the process more flexible to make products of different design without changing the value of the product. Many manufacturing companies, historically, have been able to maintain bloated or inefficient methods because of a protected market, strong brand strength or huge profit margins. The global competition is forcing these manufactures to quickly change their methods to be less wasteful, and provide value to their customers through customization and reduced cycle or delivery times. There are five-key principles that must be followed to implement lean manufacturing successfully. They are, http://www.iaeme.com/IJMET/index.asp 1025 editor@iaeme.com
Krishnamoorthy S and Ben Ruben R 1. Specify value from the standpoint of the end customer by product family. 2. Identify all the steps in the value stream for each product family, eliminating whenever possible those steps that do not create value. 3. Make the value-creating steps occur in tight sequence so the product will flow smoothly toward the customer. 4. As flow is introduced, let customers pull value from the next upstream activity. 5. As value is specified, value streams are identified, wasted steps are removed, and flow and pull are introduced, begin the process again and continue it until a state of perfection is reached in which perfect value is created with no waste. Agile manufacturing is a term applied to an organization that has created the processes, tools, and training to enable it to respond quickly to customer needs and market changes while still controlling costs and quality. The definition of leagility, a system in which the advantages of combination of lean and agile principles are combined was originally developed to manufacturing supply chain. The two paradigms lean thinking and agile manufacturing may be distinctly different but they are combined for an effective successful mechanism which eliminates the non-value adding activities and increases the flexibility of the system. Leanness means developing a value stream to eliminate all wastes including time to ensure a leveled schedule. Agile ensures that the system is completely flexible and responds to the unpredictability. These two distinct features are combined o create a system which facilitates flow and is flexible to the volatile market. 2. LITREATURE REVIEW J. Womack et al [1] discussed briefly about the lean methodology and the various key principles that must be adopted to establish a lean environment. Y. Monden et al, [2] discussed about the Toyota production system and the various tools and techniques which they applied to their organisation. M. Holweg[3] proposed a model that followed the one piece flow principle and the changes that are to be adopted to achieve it. D. Jones et al, [4] proposed the concepts of lean thinking and also they framed a model for achieving the lean production system. M. Imai[5] discussed about the kaizen approaches that are adopted in the production line that aims for continuous improvements in both the process and the system. It also empathised the formation of a cross functional team in arriving better results This is the sequel to the author’s earlier successful book, Kaizen. It also summarizes and extends much of the earlier work with examples and case studies. “Gemba Kaizen” means continuous improvement in the workplace. J. Liker[6] discussed about the 14 management principles which was followed by Toyota and also explained about the need for practicing the mentioned principles. ] M. Rother[7] et al, provided the usage of 5s and value stream mapping to identify the value adding and non value adding activities and also about the ways prescribed to eliminate the typical wastes. The Productivity Press Development Team [8] proposed a standard operating procedure that has to be followed in the shop floor to eliminate the unnecessary motions and other waiting activities. K. Suzaki [9] proposed a model which motivates the firm to achieve continuous improvements by using the lean tools and also the importance of forming a cross functional team. M. L. Spearman et al [10] proposed an integrated model to achieve pull system by consistent elimination of wastes. Emiliani, B et al,[11] framed a model that suits the business environment for practicing the lean principles and also provided a framework for business process reengineering. Kobayashi, I et al,[12] highlights 20 different skills in a broad perspective that can be used to make the lean manufacturing journey possible. It also contains an evaluation system that helps pinpoint facets where improvements are needed. Aitken et al[13] gave the definition of leagility, a system which in which the advantages of leanness and agility are combined which was originally developed for supply chains.. Mason-Jones et al.[14] discuss http://www.iaeme.com/IJMET/index.asp 1026 editor@iaeme.com
Operational Improvement by Leagile Approach that lead time reduction and enhancing the information flow across the supply chain will increase the agility in the supply chain. Their benchmarking experiment between TCT, traditional, material lead time reduction and information lead time reduction supply chain approaches shows that TCT will aid in responding quickly to the volatile demands. They also illustrate that the Total Cycle Time reduction utilizes the synergized benefits that are available from the reduction of both material and information lead time C.G. Sreenivasa et.al.[15] proposed a model to assess the agility level of a firm through 30 criteria’s to measure the current agility level. The literature provided wide information about the lean manufacturing principles and its applications at various business enterprises. The information gathered from the papers was very useful in analysing the current production system and also gave useful information about the modifications that must be made to the processes to achieve flow by consistent elimination of wastes. 3. CASE STUDY The selected air compressor manufacturing company is the leading manufacturer of air compressors in India and one of largest manufacturer of air compressors in Asia. It is an ISO 14001: 4000 certified company and also holds a BS OHSAS 18001:2007 certification. This company manufactures around 40 different varieties of air compressors. The company produces a wide range of compressors. They are classified as Piston Compressors, Electric-lubricated screw air compressors, Electric oil free screw air compressors, Portable compressors and Railway compressors. 3.1. Assembly Sequence of EN Series Air Compressors The assembly sequence of EN Series Screw Air Compressors consists of six different assembly stations.. The first station is the Canopy dis-assembly and labelling where the canopy is being dis-assembled into two parts namely top part and the bottom part, and after this the labelling is done using a label fixing tool. The next station is the cooler assembly where the cooler is being attached with the bottom canopy. Next station is the Drive and Lubrication Assembly, where the motor and the air-end is being fitted with the bottom canopy. The next station is the electrical assembly where the wiring and other electrical accessories are being fit with the assembled compressor. Once after electrical assembly is done the next station is the testing, where the assembled compressor is being tested at different conditions. After testing Pre -despatch and Inspection is done where the compressor is packed and pre despatch operations are performed. 3.2. Identification of Bottleneck Process The S0 line which comes under the Electric-Lubricated Screw Air Compressor category basically produces two different types of compressor models namely A12 and A14. The operational assembly sequence is same for both the models. The work aim was to improve the productivity by reducing the total operating cycle time by 20% by using lean tools and also to improve the agility level of the firm by using leagile approach. The net available time per shift is 510 minutes, and the total operating cycle time for A12 and A14 models are 201 minutes and 220 minutes respectively as shown in figure 1. Now after studying the entire line, various studies and analysis were done to reduce the total operating cycle http://www.iaeme.com/IJMET/index.asp 1027 editor@iaeme.com
Krishnamoorthy S and Ben Ruben R Figure 1 Identification of bottleneck stations 3.3. Methodology The methodology as shown in figure 2 was formulated on the basis of understanding the existing system thoroughly and also by discussing with the line managers. The initial task was to observe and understand the process, which gives a clear vision of the process and all activities involved in that process. The next step was to perform the video study. Video study maps the current process as it is done and waste capturing is done by analysing the video. Once after the video is taken next process is to classify the elemental activities based on the video, and then the elemental activity is segregated into value added and non value added activity. After segregating the activities, the next step is to classify the activities based on the category of the wastes and proper lean tools are identified to eliminate the wastes. Once when the waste gets eliminated a proper sequence is formed to perform the task. Finally the results are compared with the old process and the improvements are validated. Further for measuring the current agility level the structure of the company was studied initially. Later the current agility level was found out .Based on the score obtained the weak areas were found out and effort suggestions were given to improve the current agility level Figure 2 Methodology to improve the agility level 4. STAGE-1 PROCESS IMPROVEMENT 4.1. Process description of Stage-1 Canopy disassembly labelling and cooler assembly is the first station of the B1 line which produces the A12 and A14 model compressors. Canopy is the body of the air compressor which http://www.iaeme.com/IJMET/index.asp 1028 editor@iaeme.com
Operational Improvement by Leagile Approach has two parts namely the top and the bottom part. Here initially the canopy is brought to the station with the help of trolleys from the stores and being dismantled into top and bottom part. Later labelling is done on the top part and the cooler is attached to the bottom part. Fastening is done with the help of pneumatic ratchets .Attach the provided gland with the panel. Now the bottom canopy is sent for drive and lubrication assembly. After completion of labelling and cooler assembly the next process is the drive and lubrication assembly .In this process the motor and air-end which are considered as the crucial parts of the air-compressor are being assembled with the bottom canopy. Later the pulleys, belts and air hoses are being assembled to complete the drive and lubrication assembly. 4.2. Performing the video study Once after the process was observed and studied, video study was performed for waste capturing. The study was performed for A14 model compressor. Initially video study was done for the stage-1(Canopy disassembly, labelling, drive and lubrication assembly).Based on the activity the wastes was classified and the captured wastes were categorized as per the lean wastes. The time distribution is shown in Table 1. Table 1 Time distribution for stage-1 Description Time ( min) Total time for Stage-1 99.45 Total value adding time 48.05 Total non value adding time 51.50 4.3. Planning the Kaizen activities After the classifying of wastes for A14 model compressor the next step was to plan for the Kaizen’s to reduce the time spent on non-value adding activities. Before planning the kaizen’s for stage-1(Canopy disassembly, labelling, drive and lubrication assembly) some general improvements were planned ,and based on these suggested improvements, the kaizen’s were planned. They are, 1. Best Point location for storing tools and materials to be planned 2. Details of tools to be provided 3. Feasibility for a slim module trolley 4. Provision of overhead hanging tool 5. Redesigning the layout 6. Provision of an air gun 7. Laying vinyl sheet were canopy is to be stored 8. Erection of a jib arm crane 9. Provision of a low cost automated table for drive and lubrication assembly 4.4. Kaizen activities implementation 4.4.1. Provision of kit material feeding trolley 4.4.1.1. Existing problem In the current situation the materials needed for assembly arrives in two different bins and it becomes difficult for the operator to search for the materials http://www.iaeme.com/IJMET/index.asp 1029 editor@iaeme.com
Krishnamoorthy S and Ben Ruben R 4.4.1.2. Waste category Waiting 4.4.1.3. Identified kaizen A kit material feeding portable trolley is designed which has separate bins as per the assembly sequence. The bins are provided with rollers and stoppers. Separate space is provided for storing the tools and other peripherals. 4.4.1.4. Potential savings (in minutes): 10 minutes 4.4.2. Provision of motor-air end feeding trolley 4.4.2.1. Existing problem Currently the motor and air-end used in the drive and lubrication assembly is stored at the space provided near the cooler assembly point. The worker has to move every time to carry the motor air-end and the structure using the jib-arm crane to move them near the assembly point. 4.4.2.2. Waste category Movement 4.4.2.3. Identified kaizen A motor-air end feeding trolley is designed which is a portable kind of trolley which has the provision of storing the motor, air-end and the structure. It can be kept near to the drive and assembly point to reduce the time spent on movement 4.4.2.4. Potential savings (in minutes) 3 minutes 4.4.3. Best point location for storing the tools 4.4.3.1. Existing problem During the assembly process , operator moves every time in search for tools and there is no proper location for storing the tools. 4.4.3.2. Waste category Movement 4.4.3.3. Identified kaizen A bin is provided to store the tools used as per its assembly sequence .Apart from this a best point location in between the stage-1 and stage-2 was created to store the pneumatic ratchets and other air operated tools. 4.4.3.4. Potential savings (in minutes) 6 minutes http://www.iaeme.com/IJMET/index.asp 1030 editor@iaeme.com
Operational Improvement by Leagile Approach 4.4.4. Provision of unit moving trolley 4.4.4.1. Existing problem During the assembly process , operator moves every time in search for tools and there is no proper location for storing the tools. 4.4.4.2. Waste category Movement 4.4.4.3. Identified kaizen: A bin is provided to store the tools used as per its assembly sequence .Apart from this a best point location in between the stage-1 and stage-2 was created to store the pneumatic ratchets and other air operated tools. 4.4.4.4. Potential savings (in minutes) 6 minutes 4.4.5. Provision of a LCA (Low Cost Automation) for cooler sub assembly 4.4.5.1. Existing problem During the cooler assembly process, it becomes difficult for the operator to move the bottom canopy upside down and to rotate it for attaching the fans. More effort is being applied by the operator as he must wait for the other operator, and more time is spent on moving the canopy. 4.4.5.2. Waste category Movement 4.4.5.3. Identified kaizen A Low-Cost Automated rotating and lifting table is provided for lifting and rotating the canopy. Time spent for rotating and lifting the canopy is saved. 4.4.5.4. Potential savings (in minutes) 6 minutes 4.5. Total time saved in Stage-1 The total operating cycle time for stage-1(Canopy disassembly, labelling , drive and lubrication assembly) initially was 99.45 minutes. After implementing the kaizen’s the total operating cycle time was reduced to 73.15 minutes. The total time saved was 26 minutes. the percentage reduction in total operating cycle time was observed to be 26% as shown in figure 3. Figure 3 Comparison of existing and achieved cycle time http://www.iaeme.com/IJMET/index.asp 1031 editor@iaeme.com
Krishnamoorthy S and Ben Ruben R 5. TESTING PROCESS IMPROVEMENT 5.1. Process description of Stage-1 Testing process is done once after electrical assembly is done In this process oil is filled in the compressor and various parameters are to be checked at three different load conditions namely 100%, 0% and F.O(Full Open) The parameters to be checked are ambient temperature, line pressure, sump pressure, cod, voltage, frequency, power factor, fan motor current, power etc. In the testing process optimum temperature and pressure of compressor at the running condition is being tested. 5.2. Performing the video study Once after the process was observed and studied, video study was performed for waste capturing. The study was performed for A14 model compressor as shown in Table 2. Video study was done for testing operation.Based on the activity the wastes was classified and the captured wastes were categorized as per the lean wastes. Table 2 Time distribution for TESTING Description Time (min) Total time for Testing 85 Total value adding time 53 Total non-value adding time 32 5.3. Kaizen activities implementation 5.3.1. Best point location for storing the units 5.3.1.1. Existing problem Since the testing booth is located away from the S0 line , the electrical assembled canopies are kept at a location nearer to the SO line. The operator has to wait for the availability of the trolley and has to carry the unit to the test 5.3.1.2. Waste category Movement 5.3.1.3. Identified kaizen A location nearer to the testing booth was identified. Since the unit moving trolley is in use it becomes easy for the operator to move the unit from the storage location to the testing booth 5.3.1.4. Potential savings (in minutes) 4 minutes 5.3.2. Improving the pump efficiency 5.3.2.1. Existing problem The delivery rate of the pump is very slow as it takes more time fill the oil into the sump. 5.3.2.2. Waste category Waiting http://www.iaeme.com/IJMET/index.asp 1032 editor@iaeme.com
Operational Improvement by Leagile Approach 5.3.2.3. Identified kaizen A location nearer to the testing booth was identified. Since the unit moving trolley is in use it becomes easy for the operator to move the unit from the storage location to the testing booth 5.3.2.4. Potential savings (in minutes) 4 minutes 5.3.3. Provision of battery-operated gun 5.3.3.1. Existing problem Connections are given manually and it takes more time to fasten the wires. 5.3.3.2. Waste category Waiting 5.3.3.3. Identified kaizen A Battery-operated gun is provided for wiring which accelerates the job of fastening the electrical connections. 5.3.3.4. Potential savings (in minutes) 5 minutes 5.3.4. Re modifying the operation of measuring the belt tension 5.3.4.1. Existing problem The operator checks the belt tension once after the testing is over at 7 different locations and calculates the average manually. 5.3.4.2. Waste category Waiting 5.3.4.3. Identified kaizen The number of location is reduced to 4 and a calculator is provided to calculate the average A Battery operated gun is provided for wiring which accelerates the job of fastening the electrical connections. 5.3.4.4. Potential savings (in minutes) 3 minutes 5.3.5. Total time saved in Testing Operation The total operating cycle time for testing initially was 85 minutes. After implementing the kaizen’s the total operating cycle time was reduced to 69 minutes. The total time saved was 16 minutes. the percentage reduction in total operating cycle time was observed to be 18% as shown in figure 4. http://www.iaeme.com/IJMET/index.asp 1033 editor@iaeme.com
Krishnamoorthy S and Ben Ruben R Figure 4 Comparison of existing and achieved cycle times 6. AGILITY ASSESSMENT The present agility level of the firm has to be calculated in order to find out the weak area where the concentration has to be given for increasing the agility. So, the model proposed by C.G. Sreenivasa et.al (2012) has been taken to analyze the agility level. The criteria and the importance given to each criterion in calculating the agility level in the organization has been shown below. 30 criteria for measuring Agility From these 30 criterions the criteria which help to assess the agility has been identified. Thus, 23 criteria pertaining to the supply chain agility were selected. The scores obtained the firm are shown in Table 3. Table 3 Scores Earned for 23 Criteria’s No Criteria Total score Score earned Percentage 1 Organisation structure 50 24 48 2 Devolution of authority 150 87.5 58.33 3 Nature of management 300 285 95 4 Employees’ status 25 24 96 5 Employee involvement 50 50 100 6 Team working 50 50 100 7 Manufacturing set-ups 10 6.5 65 8 Product life cycle 15 15 100 9 Design improvement 15 14 93.33 10 Production methodology 10 9 90 11 Manufacturing planning 10 8 80 12 Automation 20 14.5 72.5 13 Information technology (IT) integration 25 20 80 14 Customer response adoption 20 18 90 15 Change in business and technical processes 15 15 100 16 Outsourcing 15 11 73.33 17 Value chain integration 15 13.5 90 18 Mass customization 15 11 73.33 19 Status of productivity 10 5 50 20 Status of quality 40 32.5 81.25 21 Time management 20 20 100 22 Flexibility 10 10 100 23 Innovation 15 11 73.33 Total 905 754.5 83.37 http://www.iaeme.com/IJMET/index.asp 1034 editor@iaeme.com
Operational Improvement by Leagile Approach Thus, the agility level of the firm has been found out as 83.37 % as shown in figure 5. The percentage obtained for each criterion has been computed and tabulated Thus, the criterions with lesser percentage will be considered as weak area for improvement. The percentage gap chart helps us to find out the weak areas by viewing it. Figure 5 Percentage gaps of 23 criteria’s 6.1. Suggestions to improve the agility level These works has been accomplished to identify the weak areas for strengthening it. The weak areas were identified to be in organization structure, devolution of authority, status productivity, automation and Manufacturing set-ups. The following strengthening suggestions and actions were proposed for improving the agility level of the supply chain. They are: 1. Request all the suppliers to buy computer and equipped with Internet facilities. 2. It is identified that your organization structure needs improvement. Steps have to taken for making your organization flattened and holistic. 3. Steps has to be taken for implementing Automation techniques in your company 4. It is proposed to carry out research and development activities to evolve innovative products, processes and services 5. It is proposed that the company must collaborate with research laboratories to transfer innovative ideas into commercially viable solutions. 6. It is proposed to encourage the use of information technology such as internet, intranet and video conferencing for creating virtual organization. 7. It is proposed to apply IT utilities in managing the Supply chains 8. It is proposed to develop time compression programme in your organization. 9. Personnel should be trained for enabling them to make decision without consulting and depending their superiors all the time http://www.iaeme.com/IJMET/index.asp 1035 editor@iaeme.com
Krishnamoorthy S and Ben Ruben R 10. It is proposed to incorporate the customer’s feedback quickly and within a week on your product Thus, the weak areas have been identified and the strengthening suggestions were also proposed. 7. CONCLUSIONS The detailed study of the B1 line and its products A12 and A14. Video study was performed and based on the study, elemental work table was formed to identify the value adding and non value adding activities. After analyzing the non value adding activities, kaizen’s were planned to reduce the non value adding activities. On successful implementation of the kaizen’s subsequent improvements like reduction in cycle time and an increase in productivity was observed as shown in Table 4. The current agility level of the firm was calculated and suggestions were given to improve the agility level. Apart from the implemented kaizen’s scope for future work is also discussed to reduce the total operating cycle time further. Table 4 Existing Vs Achieved Existing Cycle Achieved Cycle Time after Assembly operation time(min) implementation(min) Canopy disassembly, labelling,drive 99.45 71 and lubrication assembly Electrical assembly 60 53 Testing 85 66 PDI 58 51 Total operating cycle time 302.45 241 % reduction in toct 20 REFERENCES [1] J. Womack, D. Jones, D. Roos, the machine that changed the world, Rawson Associates, 1990. [2] Y. Monden, Toyota Production System - an integrated approach to just-in-time. 3rd Edition, Engineering and Management Press, Institute of Industrial Engineers, 1998 [3] M. Holweg, The genealogy of Lean Production. J. of Operations Management, 2007. 25, p. 420-437. [4] J. Womack, D. Jones, Lean Thinking, Siman & Schuster, USA., 1996. [5] M. Imai, KAIZEN - the key to Japan´s Competitive Success, McGraw-Hill/Irwin, 1986 [6] J. Liker, The Toyota Way: 14 Management Principles from the World's Greatest Manufacturer, McGraw –Hill, 2004. [7] M. Rother, J. Shook, J. Womack, and D. Jones, learning to see: Value Stream Mapping to add value and eliminate MUDA, Lean Enterprise Institute, 1999. [8] The Productivity Press Development Team, Standard Work for the Shop-floor. Productivity Press; New York, 2002. [9] K. Suzaki, The New Shop Floor Management: empowering people for continuous improvement. Free Press, New York, 1993. [10] M. L. Spearman, D. L. Woodruff, and W. J. Hopp, CONWIP: a pull alternative to Kanban, International Journal of Production Research, vol. 28, n. 5, pp. 879-894, 1990. [11] Emiliani, B., Stec, D., Grasso, L., Stodder, D., Better Thinking, Better Results, The Center for Lean Business Management, Kensington, CT, 2003 http://www.iaeme.com/IJMET/index.asp 1036 editor@iaeme.com
Operational Improvement by Leagile Approach [12] Kobayashi, I., 20 Keys to Workplace Improvement Revised Edition; Productivity Press, New York, NY, 1995. [13] AitkenJ, Chirstopher and Towill” Understanding implementing and exploiting lean and agility”, International journal of logistics Vol.5 No.1 pp 59-74 [14] Manson-Jones and Towill(2000) “Engineering the leagile supply chain” Intenational journal of Agile Management Systems, Vol.2 No.1 pp54-61 [15] Sreenivasa, C.G., Devadasan, S.R. and Murugesh, R. (2012) ‘Thirty criteria-based assessment of agility in a pneumatic enabling products manufacturing company’, International Journal of Services and Operations Management, Vol. 11, No. 2, pp 201-221 http://www.iaeme.com/IJMET/index.asp 1037 editor@iaeme.com