Application of remanufacturing principles to an automotive engine valve component

Transcription

1 5 th International & 26 th All India Manufacturing Technology, Design and Research Conference (AIMTDR 2014) December 12 th 14 th, 2014, IIT Guwahati, Assam, India Application of remanufacturing principles to an automotive engine valve component Manjunatheshwara K J 1, S Vinodh 2*,Vimal KEK 3 1 Post Graduate Student, Department of Production Engineering, National Institute of Technology, Tiruchirappalli ,manjunatheshwara@yahoo.co.in 2* Assistant Professor, Department of Production Engineering, National Institute of Technology, Tiruchirappalli , vinodh_sekar82@yahoo.com 3 Research Scholar, Department of Production Engineering, National Institute of Technology, Tiruchirappalli ,vimalkek.engr@gmail.com ABSTRACT With a motto to introduce concept of remanufacturing in a component manufacturing industry against the belief that remanufacturing is not implementable in such industries, an attempt has been made to modify a component design such that the product is transformedinto assembly of parts and thus facilitating remanufacturing. A case study was conducted in an Indian automotive engine valve manufacturing organisation. The reengineering study identified the potential of using an alternative design to facilitate remanufacturing of automotive engine valves. Further sustainable analysis of optimised design also has been conducted. 1 Introduction In the era of technological advancements, there is a rapid increase in the consumption of goods, automobiles and thus leading to depletion of resources abruptly. To avoid the danger of unavailability of resources for future generation, it is important for the organisations to think about material recovery. The materials post usage can be reused, recycled, remanufactured or disposed (Lee et al. 2010). Remanufacturing is considered to be best among material recovery options. Remanufacturing restores products post usage to their original specifications thereby meeting rigid environmental regulations while maintaining profitability. Remanufacturing may be defined as the End-of-Life (EoL) strategy of converting used products to as new conditions. Remanufacturing is mostly followed by industries in western countries where strict environmental regulations are imposed, while in India the concept is not so popular. There is an urgent need for the industry practitioners to understand the importance of remanufacturing strategy, which is an option of profitability. Remanufacturing is mostly adapted by industries where customer demands are highly volatile, as that of automotive and cellular phone manufacturing industries. Researchers have been focusing on applicability of remanufacturing in automotive industries. Seitz (2007) conducted a study in automotive industry and found new motives of remanufacturing to be customer orientation, market share, brand protection and providing additional source for supply of spares against traditional motives such as moral and ethical responsibility. Followed by this study Chen and Wang (2008) proposed information sharing between manufacturing and remanufacturing to facilitate remanufacturing.subramoniam et al. (2010) developed Remanufacturing Decision Making Framework (RDMF) using several strategic factors which were prioritised using Analytic Hierarchy Process (AHP). They validated the framework for automotive industry. A recent study by Saavedra et al. (2013) compared combined and dedicated models of remanufacturing in Brazilian automotive sectors and explained the benefits in combined model of remanufacturing, also proposed that the dependency of independent remanufacturers on Original Equipment Manufacturer and Remanufacturer (OEMR) would benefit independent remanufacturers. Realising the current scenario of remanufacturing studies conducted in automotive sectors, the scope for further studies is understood and efforts are to be made to apply remanufacturing strategy in Indian automotive sectors for efficient utilisation of energy and resources. Remanufacturing has been applied and considered to be profitable in assembly lines, which consists of five stages of operations namely, disassembly, cleaning, inspection, replacement, repair or refurbishment of worn out parts, and reassembly and testing. There is need to introduce remanufacturing to component manufacturing industries. With this motto to be fulfilled, an attempt is 138-1

2 Application of remanufacturing principles to an automotive engine valve component made to modify a component design to make the component as an assembly of parts and thus facilitating remanufacturing. Hatcher et al. (2011), in their study discussed Design for Remanufacturing (DfRem) from literature. They found problems focused on product design and development of methods and tools for it. Design modifications though involve high initial investment are considered to be profitable after the operations start. The case study is conducted in an Indian automotive engine valve manufacturing organisation. Three metals are joined to make an engine valve component to achieve different material properties in three different zones namely, head, stem and tip. Currently welding methodology is followed to join metals. But if design optimisation is done such that the component becomes an assembly of parts with temporary joints, remanufacturing implementation will be feasible. The schematic diagram of engine valve and three different zones is shown in Figure 1.It shall be checked if the new design helps remanufacturing, also sustainability of product with respect to new design shall be assessed. With remanufacturing introduced to Original Equipment Manufacturer (OEM), the organisation will be able to create value to stake holders while nurturing nature and society. Figure 1 Schematic diagram of engine valve 2 Methodology Products of the case organisation are studied in terms of theirvariety and usage.the automotive engine valve manufacturer produces a wide variety of IC engine valves as per customer requirements. The valves are broadly classified as Inlet and Exhaust valves based on the functions. Inlet and exhaust valves of IC engines work under different thermal and load conditions. Hence process andmaterials used to manufacture inlet and exhaust valves are different. Exhaust valves are exposed to higher temperatures than inlet valves. Hence the mode of failure is different for inlet and exhaust valves. Inlet valves are always monometallic whereas exhaust valves are bimetallic. Study of valve failures gives a clear idea. Raghuwanshi et al. (2012) analyzed internal combustion (IC) engine valve failures. According to the authors, IC engine valves usually fail when wearing occurs at head region due to interaction with valve seats.the failure may be thermal fatigue, since valves are subjected to high temperatures while working in an IC engine. Exhaust valves are subjected to higher temperature when compared to inlet valves. Especially the head region on cylinder side is exposed to higher temperatures ranging from 900 o C to 1000 o C. Hence the head material for Exhaust valves is harder one. Especially austenitic stainless steel is used for head and stem is made of martensitic low carbon steel. The two metals are joined by friction welding to obtain desired bimetallic valve. In most cases, the stem region remains unaffected since it acts just as a connecting part that transfers motion of the rocker arm. But when valve failure occurs, the entire valve is disposed while the stem is still in good condition. Hence useful material is wasted which is not a sustainable practice. It is important that separation of failure region from secure regionis done by modifying the design by means of temporary joint to facilitatereplacement of head alone in case of failure due to wear. Shu et al. (1995) discussed in detail the applicability of fastened joints in remanufacturing. The model is developed using a software package and joint is analysed for its strength to withstand actual working conditions using an analysis package. The design is also assessed for its sustainability using a compatible software package

3 5 th International & 26 th All India Manufacturing Technology, Design and Research Conference (AIMTDR 2014) December 12 th 14 th, 2014, IIT Guwahati, Assam, India 3 Case Study A 3D assembled model of Engine valve is developed as shown in Figure 2. The valves are threaded on two partsand a fastened joint is created. Figure 2 shows the assembled product and two individual parts, stem and head. Figure 2 Bimetallic Exhaust Valve The martensitic low carbon steel stem part is designed to have internal threading. Fastened joint makes the product to be disassembled easily whenever required.for internal thread,the thread diameter, thread depth and pitch are assigned as shown in Figure 3. Figure 3 Wireframe model of stem with internal threading 138-3

4 Application of remanufacturing principles to an automotive engine valve component Thus the unaffected stem part can be used again in remanufacturing valve if found to be not affected by failure of valve.the austenitic stainless steel head is threaded externally.for external thread, the thread diameter, thread depth and pitch are as assigned as shown in Figure4. The head part is mostly affected due to high temperature of combustion process and fatigue load is replaced with a new one while remanufacturing. Thus meeting the customer requirement while also ensuring the sustainability ofproduct. Figure 4 Wireframe model of Head with external threading The developed model is analysed using the analysis package to validate the design. The product is analysed for its sustainability. The analysis results are discussed in the succeeding sections. The valve is subjected to an external load on the valve head of magnitude up to 15MPa, valve will be held by a collar to facilitate sliding motion and rotation with respect to its axis. 4 Results and Discussions From Figure 4, it can be seen that fastened joint is strong enough to withstand the actual working conditions under static loads. The results showed that Von Mises stress is high in head region and is very low at the joint.this supports the idea of using proposed design to facilitate remanufacture of engine valves

5 5 th International & 26 th All India Manufacturing Technology, Design and Research Conference (AIMTDR 2014) December 12 th 14 th, 2014, IIT Guwahati, Assam, India Figure 4 Stress acting on the assembled valve Sustainability analysis of two parts are analysed individually and the following results are obtained.significant process steps having higher impact on environment are taken into consideration for analysis. Material: 0.06 kg CO 2 Manufacturing: 0.30 kg CO 2 Use: 1.70E-3 kg CO kg CO 2 End of Life: 7.15E-4 kg CO 2 Figure 5 Carbon Footprint of valve head Material: 0.04 kg CO 2 Manufacturing: 0.02 kg CO 2 Use: 1.61E-3 kg CO kg CO 2 End of Life: 6.76E-4 kg CO 2 Figure 6 Carbon Footprint of valve stem The above results showed that though overall carbon footprint caused by Stemis very less compared to head of the valve, carbon footprint during End-of-Life phase is almost equal. Similarly from analysis results Water Eutrophication, Air acidification and Energy consumption during End-of-life of Head and Stem are 138-5

6 Application of remanufacturing principles to an automotive engine valve component almost equal. Hence there exists a real scope forrecovery of stem and thus upholding manufacture of product through sustainable practices. 5 Conclusions Since product take back helps adding an additional source of supply, the burden to rely upon one channel is penalised. Demand can be thus met readily while fulfilling the sustainability criteria. The study is a breakthrough for sustainable product development. The application of this study would result in large material recovery especially in the age of depletion of resources. The idea of remanufacturing engine valves has been accepted by practitioners. They believe that this study will provide new insights over the scope for making further improvement in their designs and also for continuous improvement. 6 Future research direction The study can further be extended by developing the product take back schemes to recollect the products post their usage. The returned products and unaffected stems will provide additional supply of spares. Measures are to be taken for customer involvement by explaining References Chen, K., & Wang, J. (2008). The data mining technology based on CIMS and its application on automotive remanufacturing. First International Workshop on Knowledge Discovery and Data Mining, WKDD 2008 IEEE: Hatcher, G. D., Ijomah, W. L., & Windmill, J. F. C. (2011). Design for remanufacture: a literature review and future research needs. Journal of Cleaner Production, Vol. 19, No. 17, pp Lee, H. B., Cho, N. W., & Hong, Y. S. (2010). A hierarchical end-of-life decision model for determining the economic levels of remanufacturing and disassembly under environmental regulations. Journal of Cleaner Production Vol. 18, No. 13, pp Saavedra, Y., Barquet, A. P., Rozenfeld, H., Forcellini, F. A., &Ometto, A. R. (2013). Remanufacturing in Brazil: Case Studies on the Automotive Sector. Journal of Cleaner Production. Seitz, M. A. (2007). A critical assessment of motives for product recovery: the case of engine remanufacturing. Journal of Cleaner Production, Vol.15, No. 11, pp Subramoniam, R., Huisingh, D., &Chinnam, R. B. (2010). Aftermarket remanufacturing strategic planning decision-making framework: theory & practice. Journal of Cleaner Production, Vol. 18, No. 16, pp Raghuwanshi, N. K., Pandey, A., &Mandloi, R. K. (2012). Failure analysis of internal combustion engine valves: A review. International Journal of them the benefits involved. Study has to be conducted in order to reduce the cost of system and process modification or design and development to facilitate remanufacturing. Innovative Research in Science, Engineering and Technology, Vol. 1, No. 2, pp Shu, L. H., & Flowers, W. C. (1995). Considering remanufacture and other end-of-life options in selection of fastening and joining methods. Proceedings of the International Symposium onelectronics and the Environment,IEEE, pp