Application of SMED in Rim Manufacturing Plant for Light Motor Vehicle

Transcription

1 IJSTE - International Journal of Science Technology & Engineering Volume 2 Issue 11 May 2016 ISSN (online): X Application of SMED in Rim Manufacturing Plant for Light Motor Vehicle Sunish Rao Shreyas Ranade Rohit Yadav Abhijeet Suryawanshi Prof. Prasad Waste Abstract Nowadays, the overall production time has become an important factor in any mass production company to survive the global competition and cope up with customer demands. It has become necessary to reduce the production time which in turn can improve productivity. To serve this purpose, various concepts of lean manufacturing like SMED (Single Minute Exchange of Die), Kaizen, 5S are used. This paper aims at reducing Set-up or Change over time of rim expander die by applying concept of SMED in Rim Manufacturing Plant for Light Motor Vehicle which can improve productivity thus generating more revenue for the company. Changeover time required by conventional method as well as after implementation of SMED is calculated and results have shown significant reduction in changeover time by almost about 80-85%. Keywords: Changeover time, lean manufacturing, productivity, SMED, Kaizen I. INTRODUCTION Due to growing global competition across the industries and growing customer demands, the need of the hour for organization or industries is to survive in these severe conditions in the market. This unscrupulous competition has made industries to think of working in a different way and more efficient way. They should keep themselves alive and updated in this fierce competition by optimizing their resources like time and money. As a result various lean manufacturing concepts have evolved over time. One such concept, Single Minute Exchange of Die (SMED), mainly focuses on recognition of internal and external operation to improve the efficiency of the production process[1,2]. Due to varied customer demands, it becomes necessary for companies to improve their flexibility in production i.e. improving the potential of batch production so as to satisfy the demand of their clients[3]. Lean principles are all focused on further improvement of current process which will ultimately lead to improved efficiency thus leading to higher profitability[4]. The concept looks simple to unfamiliar person but achieving that goal is usually harder than one can imagine. And, although it may be harder, the final results and improvements achieved through that are quite rewarding, satisfying and further motivating to transform that process into more efficient one. Shigeo Shingo has provided the foundations for SMED implementation. He has described eight techniques for implementing SMED (Shingo 1985)[5]. They are: Separate internal from external setup operations Convert internal to external setup Standardize function, not shape Use functional clamps or eliminate fasteners altogether Use intermediate jigs Adopt parallel operations Eliminate adjustments Mechanization. The most basic thing is to study all the parts of changeover process, identify them as internal or external, then try to convert internal processes to external ones or even try to eliminate internal processes by finding an alternate way to serve the purpose. Internal process is the one which can be performed only when the machine is stopped like lifting of current die and installing of All rights reserved by 413

2 another one while the external process is the one that can be performed when machine is running such as transportation of various tools, dies, etc. This has started various trends in industry like Increase in the variety of products produced. Increase in the quality of products. Reducing the product lifecycle time. Reducing various costs incurred in changeover process. II. PRODUCTION OF RIM Metal coils are uncoiled to form rectangular sheets. 1) These sheets are bent to form a cylinder. 2) The opening of the cylinder is butt welded to form a closed cylinder. 3) The expander machine expands to imprint its insert profile on the cylinder to form a rim. Fig. 1: Rim Manufacturing Process III. WORKING PRINCIPLE OF RIM EXPANDER MACHINE Fig. 2: Rim Expander Die 1) Hydraulic Arrangement pushes the taper ram forward. This forward movement pushes the insert radially outwards. 2) The inserts are connected to T-sliders which slide in the T-slot in the outer body. Conventional changeover process: The changeover includes detachment of the outer body from taper ram. This is accomplished by the following process. 1) A bolt is removed, then washers equivalent to 10mm thickness are added to it in such a way that minimal thread contact occurs between bolt and t-slider. 2) Now, the bolt is tightened which makes the insert slide on the bolt thus disengaging contact between the insert and inner ram. All rights reserved by 414

3 Fig. 3: Principle of retraction of insert 3) This process is repeated for twelve bolts so as to completely lose contact with the inner tapered ram. 4) This process needs to be carried out for two expanders which are placed opposite to each other. This is a time consuming and tedious process which also requires increased labour resources. Implementing SMED concept: Brainstorming for possible solutions: Fig. 4: Possible Solutions 1) Solution 1: Using single nut of thickness equal to total thickness of washers required for each bolt fastening. 2) Shortcoming: Time consuming process as it is required to put nut 12 times. Therefore much less time is saved and thus the solution provides very small reduction in changeover time 3) Solution 2: Using C-washers for fastening instead of washers 4) Shortcoming: Less safety and less reliability as it can break due to excessive stresses induced by weight of components of expander die. 5) Solution 3: Designing of locking ring which would lock all the twelve bolts at once. It will also eliminate the tedious and lengthy process of removing each bolt individually and putting washers. 6) Advantage: Time reduction upto more than 80 percent and in turn increasing the batch production rate. Thus the final solution is much more feasible although it s slightly higher cost of production than previous solutions. All rights reserved by 415

4 IV. RESULTS AND DISCUSSIONS Table 1 Before SMED Sr. no. Process name Type Time taken (minutes) Cumulative Time 1 12 bolts removed Internal 1.5 X 12= Adding washers to each bolt Internal 1 X 12= Fitting bolts again Internal 1.5 X 12= Installing I-bolts Internal 1X5= Removing expander with crane (2) Internal 10 X 2= Changing inserts Internal Removing bolts Internal 1.5 X 12= Removing washers Internal 1 X 12= Reinstalling bolts Internal 1.5 X 12= TOTAL TIME 166 ( 2hr 46min) Table 2 After implementing SMED (locking ring) Sr. no. Process name Type Time taken (minutes) Cumulative Time 1 Aligning locking ring Internal Expanding the die Internal Twisting locking ring to lock all the bolts at once Internal Retracting expander die Internal Installing I-bolts Internal 1X5= Removing expander with crane (2) Internal 10 X 2= Fig. 5: Graphical representation of cumulative time required for various operations before and after SMED V. SCOPE AND LIMITATIONS 1) In the future locking ring can be manufactured using composite materials, which will increase the strength, reduce the weight and cost as well but, this process will require a lot of research and development consuming a lot of time and resources. 2) Every expander will require individual locking ring but the time saved from it is priceless. VI. CONCLUSIONS 1) After implementing SMED concept, setup and changeover time is reduced to 27.3 minutes from 166 minutes. 2) More batch production becomes possible as a result of this. 3) Inventory costs reduced to a great extent. Thus less space required to operate the overall plant. 4) Labour cost reduced in turn increasing lean production rate. All rights reserved by 416

5 REFERENCES Papers [1] Silvia Pellegrini, DevdasShetty and Louis Manzione Proceedings of the 2012 Study and Implementation of Single Minute Exchange of Die (SMED) Methodology in a Setup Reduction Kaizen International Conference on Industrial Engineering and Operations Management Istanbul, Turkey, July 3 6, [2] Vipan Kumar, Amit Bajaj Assistant Professor, ME Department, GTB Group of Institutions, Malout. The Implementation of Single Minute Exchange of Die with 5 S in Machining Processes for reduction of Setup Time International Journal on Recent Technologies in Mechanical and Electrical Engineering (IJRMEE) ISSN: Volume: 2 Issue: [3] Yashwant R. Mali, Dr. K.H. Inamdar Changeover time reduction using smed technique of lean manufacturinginternational Journal of Engineering Research and Applications (IJERA) ISSN: Vol. 2, Issue 3, May-Jun 2012, pp [4] Pankajkumar. J. Mistry, Mukesh DesaiSet Up Change Time Optimization Using Single Minute Exchange of Die (SMED) Methodology. International Journal of Research in Electronics and Communication Technology (IJRECT 2015) 2015, IJRECT All Rights Reserved 34 Vol. 2, Issue 1 Jan. - Mar Books [5] Shigeo Shingo - A Revolution in Manufacturing TheSmedSystem. All rights reserved by 417