PLASTİK ENJEKSİYON TESİSLERİNDE ALTI SİGMA: YENİ ÜRÜN ÜRETİMİNDE KUSURLU PARÇALAR HAMMADDE OLARAK YENİDEN KULLANILMALI MI?

Yıl 2021, Cilt: 32 Sayı: 2, 341 - 363, 31.08.2021

Meryem Uluskan

https://doi.org/10.46465/endustrimuhendisligi.876034

Öz

Üretim işletmelerinde, kusurlu ürünlerin yeniden işlenip üretime hammadde olarak tekrar dahil edilmesi, hurdayı azaltma ve verimli malzeme kullanımı avantajları sağlamaktadır. Bununla birlikte, plastik enjeksiyon süreçlerinde yeni parçaların üretiminde geri kazanılmış kusurlu plastik parçaların hammadde olarak kullanılması nihai ürün için estetik sorunlar yaratabilir. Diğer taraftan kalitenin estetik boyutunun müşteri beklentilerini karşılaması rekabet avantajı sağlamaktadır. Bu göz önüne alındığında, bu çalışmada, beyaz eşya endüstrisinde faaliyet gösteren bir plastik enjeksiyon tesisinde üretimi yapılan bir parçanın renk bozukluğu olarak ortaya çıkan estetik probleminin kök nedeni ortaya çıkarılmış ve iyileştirme yapılmıştır. Renk bozukluğu hatası nedeniyle oluşan yüksek hurda oranlarını azaltmak için Altı Sigma TÜAİK metodolojisi uygulanmış ve hatanın yeni parçaların üretiminde hurda plastik malzemelerin eritilerek yeniden hammadde olarak kullanılmasından kaynaklandığı tespit edilmiştir. Bu nedenin ortadan kaldırılmasıyla süreç yeteneği geliştirilmiş, 3 sigma süreç yeteneği 4,7 sigma seviyesine çıkarılmış ve ürünün estetik görünümü iyileştirilmiştir. Bu çalışma, beyaz eşya gibi ürünler için, kusurlu plastik parçaların hammadde girdisi olarak üretimde tekrar kullanılmasının uygulanabilir bir yaklaşım olmadığını göstermiştir.

Anahtar Kelimeler

Altı Sigma, Plastik Enjeksiyon, Hurda Malzemenin Geri Dönüşümü, Renk Bozukluğu Problemi, Beyaz Eşya Sektörü, Household Appliances

SIX SIGMA IN PLASTIC INJECTION MOLDING: REUSE DEFECTIVE PARTS IN NEW ARTICLE PRODUCTION AS RAW MATERIAL INPUT OR NOT?

Öz

In production plants, re-processing of defective products and re-incorporating them into production as raw materials provides the advantages of reducing scrap and efficient use of material. However, using recycled defective plastic parts as raw materials in the production of new parts in plastic injection processes can create aesthetic problems for the final product. On the other hand, the aesthetic dimension of quality that fulfills customer expectations provides competitive advantage. Considering this, in this study, the root cause of the aesthetic problem that occurs as discoloration of a particular component manufactured in a plastic injection facility operating in the white goods industry was revealed and improvement was made. Six Sigma DMAIC methodology was applied to reduce high scrap rates caused by discoloration errors, and it was determined that the error was caused by reusing scrap plastic parts as raw materials in the production of new articles. With the elimination of this cause, the process capability was improved, the 3 sigma process capability was increased to the level of 4.7 sigma and the aesthetic appearance of the product was improved. This study has shown that the reutilization of defective plastic parts as raw material input in new article production is not a viable approach for particular products such as white goods products.

Anahtar Kelimeler

Six Sigma, Plastic Injection Molding, Recycling of Scrap Material, Discoloration Defect, Household Appliances

Kaynakça

• Antony, J., Snee, R., & Hoerl, R. (2017). Lean Six Sigma: yesterday, today and tomorrow. International Journal of Quality & Reliability Management, 34(7),1073-1093. Doi: https://doi.org/10.1108/IJQRM-03-2016-0035
• Aziz, A. A. B., Sulaiman, S., Moe, A. L., & Bin Abu, A. (2015). Investigation of Plastic Injecting Moulding Process Optimization in Complex Shape Product. In Applied Mechanics and Materials (Vol. 695, pp. 260-264). Trans Tech Publications Ltd. Doi: https://doi.org/10.4028/www.scientific.net/AMM.695.260
• Bharti, P., Khan, M., & Singh, H. (2011). Six Sigma Approach For Quality And Performance Excellence In Plastic Injection Molding Industry-A Case Study And Review. International Journal Of Research In Commerce And Management. 2(2), 58-65.
• Birley, A. W. (2012), Plastics Materials: Properties And Applications, Springer Science and Business Media, New York, USA.
• Brady, J. E., & Allen, T. T. (2006). Six Sigma literature: a review and agenda for future research. Quality and Reliability Engineering International, 22(3), 335-367. Doi: https://doi.org/10.1002/qre.769
• Desai, D., & Prajapati, B. N. (2017). Competitive advantage through Six Sigma at plastic injection molded parts manufacturing unit. International Journal of Lean Six Sigma, 8(4), 411-435. Doi: https://doi.org/10.1108/IJLSS-06-2016-0022
• Evans, J. R. and Lindsay, W. M. (2014), An Introduction To Six Sigma And Process Improvement, Cengage Learning, Stamford, CT, United States.
• Gordon Jr, M. J. (2010), Total Quality Process Control For Injection Molding (Vol. 5), John Wiley and Sons, Hoboken, New Jersey, United States.
• Kairulazam, C. K. A. C. K., Hussain, M. I., Mohd Zain, Z., & Lutpi, N. A. (2014). Reduction of rejection rate for high gloss plastics product using six sigma method. In Applied Mechanics and Materials (Vol. 606, pp. 141-145). Trans Tech Publications Ltd. Doi: https://doi.org/10.4028/www.scientific.net/AMM.606.141
• Khan, R. M., & Acharya, G. (2016). Plastic injection molding process and its aspects for quality: a review. European Journal of Advances in Engineering and Technology, 3(4), 66-70.
• Khavekar, R., Vasudevan, H., & Modi, B. (2017). A comparative analysis of Taguchi methodology and Shainin system DoE in the optimization of injection molding process parameters. In IOP Conference Series: Materials Science and Engineering (Vol. 225, No. 1, p. 012183). IOP Publishing.
• Kim, J. K., Kim, J. S., Lee, J. H., & Kwak, J. S. (2017). A Study on Dimension Optimization of Injection-molded Automotive Bumper by Six Sigma. Journal of the Korean Society of Manufacturing Process Engineers, 16(6), 109-116. Doi: https://doi.org/10.14775/ksmpe.2017.16.6.109
• Koh, B. W., Kim, J. S., & Choi, H. G. (2008). Estimation of Process Parameters Using QFD and Neural Networks in Injection Molding. IE interfaces, 21(2), 221-228.
• Lo, W. C., Tsai, K. M., & Hsieh, C. Y. (2009). Six Sigma approach to improve surface precision of optical lenses in the injection-molding process. The International Journal of Advanced Manufacturing Technology, 41(9), 885-896. Doi: https://doi.org/10.1007/s00170-008-1543-0
• Maged, A., Haridy, S., Kaytbay, S., & Bhuiyan, N. (2019). Continuous improvement of injection moulding using Six Sigma: case study. International Journal of Industrial and Systems Engineering, 32(2), 243-266.
• Montgomery, D. C. (2005). Introduction to Statistical Quality Control. John Wiley & Sons: Hoboken, NJ, USA.
• Niaounakis, M. (2014), Biopolymers: Processing and Products, William Andrew, Elsevier, Oxford, United Kingdom.
• Safwat, T., & Ezzat, A. (2008, December). Applying Six sigma techniques in plastic injection molding industry. In 2008 IEEE International Conference On Industrial Engineering And Engineering Management (pp. 2041-2045). IEEE. Doi: https://doi.org/10.1109/IEEM.2008.4738230
• Timans, W., Ahaus, K., & Antony, J. (2014). Six Sigma methods applied in an injection moulding company. International Journal of Lean Six Sigma, 5(2), 149-167. Doi: https://doi.org/10.1108/IJLSS-07-2013-0037
• Uluskan, M. (2016). A comprehensive insight into the Six Sigma DMAIC toolbox. International Journal of Lean Six Sigma, 7(4), 406-429. Doi: https://doi.org/10.1108/IJLSS-10-2015-0040
• United States Environmental Protection Agency (EPA) official website (2020), Retrieved from https://www.epa.gov/eg/plastics-molding-and-forming-effluent-guidelines