Hazır giyimde yalın üretim metodları ile dikim verimlilik optimizasyonu
Sewing productivity optimization with lean manufacturing methods in apparel industry
Yazar: ŞADAN ESEN
Danışman: PROF. DR. FATMA KALAOĞLU
İstanbul Teknik Üniversitesi / Lisansüstü Eğitim Enstitüsü / Tekstil Mühendisliği Ana Bilim Dalı / Tekstil Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2024
Konu: Tekstil ve Tekstil Mühendisliği = Textile and Textile Engineering
Dizin: Hazır giyim endüstrisi = Ready made wear industry

Özet:
Yalın üretim sistemi işletmelere rekabet avantajı sağlayan üretim tekniklerinin başında gelmektedir. Yalın üretim katma değersiz adımların yok edilerek, stokların azaltılması, tedarik sürelerinin kısaltılması gibi iç müşteri odaklı çalışarak süreçlerin iyileşmesine hizmet eden bir üretim sistemidir. Basit anlamda yalın; daha az kaynakla, müşteri için daha fazla değer yaratmaktır. Yalın üretimin temellerini; müşteri isteklerinin belirlenmesi, değer akışının oluşturulması, çekme sisteminin oluşturulması, proses akışının sağlanması, yalın üretimin sürekli elde edilmesi oluşturmaktadır.
Araştırmanın amacı, üretim işletmeleri içerisinde önemli bir paya sahip olan hazır giyim işletmesinde yalın üretime geçişi sağlamak amacıyla yalın üretim metodlarını ve pratiklerini kullanarak israf kaynaklarını ve gelişim alanlarını görünür kılmak ve üretim sürecinin önemli bir adımı olan dikim bölümü için yeni bir hat tasarımı ve dengeleme çalışması yaparak verimliliği optimize etmektir.
Bu çalışma yalın üretim yapan bir işletmenin özelliklerini, yalın üretim süreçlerinin nasıl oluşturulabileceğini, bu süreçte karşılaşılan sorunları araştırması ve bu sorunları engellemek için uygulamada yapılması gerekenleri belirlemesi nedeniyle yalın üretim yapmak isteyen işletmeler için faydalı olabilir.
Yalın üretim çalışmaları yapan tedarikçiler, üretim sistemlerini kapsamlı bir şekilde analiz ederek yalın üretime özgü teknikleri kullanarak işletmelerinin performans düzeylerini optimize etmeye çalışırlar. İşletmelerdeki uygulamalar, üretim yapılan endüstiyel gereksinimler değişkenlikler gösterebilmekte ancak kaliteli, tam zamanında ve minimum israf ile yalın üretim felsefesinde temel ilkeler ışığında prensipler değişmemektedir.
İşletmelerde sürekli gelişimi sağlamak maksadıyla müşteriyi odağa alan, üretimde oluşan tüm israf kaynaklarını ortadan kaldırmayı amaçlayan yalın üretim metodolojisi dünyada giderek yaygınlaşmaktadır, bu çerçevede hazır giyim işletmeleri için de israf kaynaklarının tespit edilerek, sürekli iyileşmenin sağlanması kaçınılmazdır. 
Çalışmada öncelikle yalın üretim felsefesi, tanımı ve üretim ilkeleri incelenmiş, sonrasında yalın üretim araçları hakkında bilgi paylaşılmıştır. Çalışmanın uygulama bölümü orta ölçekli bir hazır giyim fabrikasında yapılan detaylı uygulamayı içermektedir. Bu aşamada işletmenin mevcut durumu spagetti diyagramı, iş zaman etüd ölçüm bulguları paylaşılmış israf ve kayıpları görünür kılacak değer akış haritalama çalışması yapılmış ve hat dengeleme çalışmaları ile elde edilen üretimdeki verimlilik artış değerleri paylaşılmıştır.

Abstract:
The lean production system stands as a forefront manufacturing technique offering competitive advantages to businesses. Lean production involves eliminating non-value-added steps, reducing inventory, and shortening supply lead times, thereby enhancing processes through customer-centric practices. In essence, lean is about creating more value for the customer with fewer resources. The foundations of lean production include identifying customer demands, establishing value streams, creating a pull system, ensuring process flow, and consistently achieving lean production.
The research aims to facilitate the transition to lean production within a significant player in the manufacturing industry, specifically a ready-to-wear clothing business. The objective is to utilize lean production methods and practices to reveal waste sources and improvement areas, and to optimize efficiency by designing a new production line and balancing the sewing department, a crucial step in the production process. This study could be valuable for businesses aspiring to implement lean production by investigating the characteristics of a lean-operating company, establishing processes for lean production, researching challenges faced in this process, and determining practical solutions to overcome these challenges.
Suppliers engaged in lean production initiatives strive to optimize performance levels by extensively analyzing production systems and applying lean-specific techniques. While applications may vary due to industrial requirements, the fundamental principles of delivering quality, just-in-time, and minimal waste remain consistent within the lean philosophy.
To foster continuous improvement within businesses, the lean production methodology, which focuses on the customer and aims to eliminate all forms of waste in production, is increasingly gaining prominence worldwide. In this context, identifying waste sources and ensuring continuous improvement becomes essential for ready-to-wear clothing businesses.
The current and future position of the company is evaluated using value stream mapping, spaghetti diagrams, and value analysis. In addition, wastage in production processes has been reduced with the line balancing technique and other lean applications. The findings showed that improvement in lean performance can be achieved by implementing a carefully planned roadmap. Parallel to the work done, the thesis was organized as follows.
In the introduction part of the thesis, a brief information about lean production principles is given.
In the second part, the history of mass production systems and the emergence of lean production are explained. In addition, five principles of lean production, namely value, value stream, flow, pull systems, and excellence, were defined and just-in-time, kanban, poke-yoke, jidoka, total efficient maintenance, one-piece flow, one-minute mold change, heijunka, 5S, and kaizen were explained.
In the third chapter, lean production application is given with many different examples from the literature. It was noticed that value stream mapping, kaizen, 5S, process analysis, and line balancing techniques were mainly used in the conversion of production to lean production.
In the fourth chapter, the methodology and application procedure applied in the study are determined. Thus, the roadmap was drawn. In addition, the techniques and applications inherent in the lean transformation used in practice are specified.
In the fifth chapter, a lean transformation application was carried out in a selected apparel manufacturer, and the findings were given. Findings and interpretations of value stream mapping, line design and balancing studies within the scope of lean development activities are included. In line with the data collected and observations made, development activities were carried out by showing methods to eliminate waste sources occurring in the production process on the future state map. Using the time study method, one of the work study techniques, the processes required to produce the product and the calculated standard times are given. In the study, the production line balancing results carried out to balance the production line of the ready-made clothing product and the comparison results of the current situation and the balancing results are presented. In order to reach optimum levels of production efficiency, lean production methods were used in the lean development journey.
In the last section, the study is summarized by presenting suggestions for further research. Lean production system is one of the leading production techniques that provide competitive advantage to businesses. Lean production is a production system that serves to improve processes by eliminating non-value-added steps, reducing stocks, shortening supply times, and working with an internal customer focus. The main goal in lean production is to perfect value-creating activities and eliminate activities that do not add value. Value-creating activities are an integrated whole, starting from project development to manufacturing, assembly, purchasing, distribution and customer assurance. For this reason, the effects of lean production show themselves in this whole. Identifying and eliminating waste sources occurring in production processes is of great importance for the ready-made clothing industry as well as for all sectors. With the study, it was determined that the lean production techniques that can be primarily used in the sewing department are product family selection, process analysis, 5S work, workforce training, layout arrangements, total quality practices and kanban technique. With the application of these techniques, the lean production system will become effective in the business. With the selection of the product family, work is done on the model that is produced the most in terms of volume. By looking at the product route, a common improvement road map is determined for models that follow the same path. Reductions in spaghetti and value stream maps mean a reduction in product unit time, and thus the product can be shipped to the customer in a shorter time. Within the scope of the study, a picture of the current situation was taken and the activities to be carried out were determined. The value flow time was shortened by preventing waits and wastes between processes. The main purpose of lean production studies is to shorten the value flow day time. In this way, by shortening the production time, it is possible to reduce production costs, increase productivity and gain from the working area. Improvement was achieved in quality performance indicators. In addition to the detection of non-conformities by the input product quality control, process quality control and final quality control officer with total on-site quality practices, each employee reduces the in-line repair, wastage and second quality rates by not purchasing the faulty part in the work. In the light of all these studies, it has been seen that lean production methods can be successfully applied in ready-made clothing and apparel businesses. Lean production methods, which are used more frequently in the automotive and sub-industry, find application in many sectors today. Many companies are also implementing successful practices in the textile and ready-made clothing industry.
In conclusion, the thesis delves into the optimization of sewing efficiency in ready-to-wear clothing manufacturing using lean production methods. By uncovering waste sources, implementing value stream mapping, and enhancing production processes, the study showcases how lean production principles can significantly improve manufacturing operations. As businesses continue to seek ways to enhance competitiveness, the integration of lean production methodologies remains a powerful avenue for achieving sustainable success.