Elektronik kart üretiminde çizelgeleme problemleri için süreç akışını dikkate alan bütünleşik bir yaklaşım ve uygulama
An integrated approach and application considering process flow for scheduling problems in electronic card production
Yazar: ÖMER FARUK ÜNAL
Danışman: DOÇ. DR. ŞEYDA SERDAR ASAN
İstanbul Teknik Üniversitesi / Lisansüstü Eğitim Enstitüsü / Endüstri Mühendisliği Ana Bilim Dalı / Endüstri Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2023
Konu: Endüstri ve Endüstri Mühendisliği = Industrial and Industrial Engineering
Dizin: Hat çizelgeleme = Line scheduling

Özet:
Elektronik kartlar günlük yaşantımızda kullanılan telefon, televizyon, bilgisayar, otomobil ve akıllı cihazlar gibi birçok üründe bir alt bileşen olarak kullanılmakta ve hayatımızda önemli bir yer tutmaktadır. Bu ürünlerin verimli bir şekilde çalışması elektronik kartların uygun tasarımına, üretimine ve kalitesine bağlıdır.
Teknolojinin gelişimiyle beraber ürün çeşitliliğinde yaşanan artış üretimdeki kapasite kısıtları göz önünde bulundurulduğunda çok fazla model geçişine neden olmakta ve bu geçişler için katma değersiz ara operasyon ve sürelere katlanılmaktadır. Üretimde verimsizliğe neden olan bu durumlar için yenilikçi yaklaşımlar ile verimlilik artışını sağlayacak çalışmalara ihtiyaç vardır.
Bu çalışmada elektronik kart üretimi çizelgeme problemleri ele alınmış ve elektronik sektöründe var olan verimlilik arttırma ve maliyet düşürme amaçlı çalışmalara katkı sağlanması motivasyonuyla gerçekleştirilmiştir. Yapılacak uygulama birbirinden farklı özellikteki elektronik kartların, birbirinden farklı özellikteki üretim ve test hatlarında talebe karşılık verecek ve maksimum faydayı sağlayacak üretim planına odaklanmaktadır. Bu problem yeterli zamanda optimum çözümün bulunamayacağı NP-zor optimizasyon problemi sınıfında yer almaktadır. Bu nedenle problem çözümü için aynı anda tüm elektronik kartların malzeme kırınımı ve ortak malzeme kullanımı, malzeme kullanım miktarları, talepleri, operasyon süreleri, süreç akış haritalarında uğrayacağı istasyonlar ve sıraları göz önünde bulundurularak bir kümeleme analizi yapılmaktadır. Oluşan kümeler otomatik dizgi hatları için en büyük üretim miktarını amaçlayan 0-1 karma tamsayılı matematiksel model içerisine yerleştirilmektedir. Son aşamada tüm üretim istasyonlarının dikkate alınması için simülasyon analizi yapılmaktadır. Çalışmada yenilikçi bütünleşik bir yaklaşım ile süreç akışı dikkate alınarak tüm üretim istasyonları aynı anda göz önünde bulundurulmuş, böylece üretim istasyonları arasındaki ilişki incelenerek hem darboğaz istasyonların belirlenmesi sağlanmış hem de alınacak aksiyonların mevcut üretim sistemine olan katkısı ortaya çıkarılmıştır.
Önerilen yaklaşım çok çeşitli az hacimli üretim yapan, yüzlerce farklı ürüne sahip, birden çok yüzey montaj teknolojisi (SMT) özelliğine sahip otomatik dizgi hattı olan, birden çok süreç akışına sahip ve birden çok test ayar istasyonuna sahip bir elektronik kart üreticisinin çizelgelemesi için uygulanmıştır. Uygulama sonucunda her biri birbirinden farklı özellikte olan elektronik kartların, birbirinden farklı özellikteki üretim ve test hatlarında talebe karşılık verecek ve maksimum faydayı sağlayacak üretim planına odaklanılarak üretim miktarında %22 oranında iyileştirilme sağlanmıştır.

Abstract:
Electronic cards are used as a subcomponent in many products such as mobile phones, televisions, computers, cars and smart devices used in daily lives and have an important place in our lives. The efficient working of these products depends on the design, manufacturing and quality of electronic cards.
Considering the capacity constraints in production, the increase in product diversity with the development of technology causes many setups and non-value-added operations and times are endured. Innovative approaches and studies that will increase productivity are needed for these situations that cause inefficiency in production.
Technology causes many changes in the design and efficiency criteria of electronic cards. The production operation, which was previously called manual insertion (MD), is gradually being replaced by automatic typesetting methods, which are called through-hole technology (THT) and surface-mount technology (SMT), which provide efficiency advantages in production. SMT enables high-speed insertion machines to automatically place hundreds of materials onto the electronic board in just a few seconds. SMT, which provides much more advantages compared to MD in terms of efficiency and quality, has an important place in the design criteria. Although SMT insertion lines vary depending on their features and technology level, they can reach up to 100 materials per second with the appropriate machine configuration. On the other hand, in MD lines where production is based on manpower, there is variation depending on the number of operators, but in a production line where 5 operators work, less than 1 material can be placed per second on average. The number of materials on an electronic card varies between 10 and 1500 depending on the size, design, function of the card and the product to be used. SMT materials have the largest share in the total number of materials. As it can be understood from the difference between the operations, companies intensify their work for SMT in insertion operations and try to come up with a plan based on SMT materials. SMT is the most important production step for electronic board production. This study was carried out with the motivation of solutions to the scheduling problems in the sector for the purpose of increasing efficiency and reducing costs. This study proposes a scheduling model for SMT insertion lines. 
In order to respond to customer demands in the electronic card production sector, production plans with "high variety - low production" feature are needed. This leads to an increase in preparation times and a decrease in productivity. Studies are needed both to increase the capacity utilization rates of the machines and to reduce the preparation times. The application to be made focuses on the production plan that will respond to the demand and provide maximum benefit in the production and test lines of different features of the electronic cards.
Electronic card production stations are designed to differ depending on the main product to be installed. There are two different base stations in production: automatic Insertion, test Adjustment. Electronic cards, whose insertion operations are completed, are subjected to a series of short circuit and function tests at test stations in order to complete the necessary quality control processes. The test to be applied varies depending on the product to which the electronic board will be assembled. For example, an electronic card to be installed in a washing machine is subjected to a simulation that undergoes all the processes that will be required during a washing process in the function test and it is ensured that all its functions work. As the content of the function test changes depending on the product, the capacity determination studies of the relevant production stations also differ. This study proposes an integrated model for automatic insertion and test adjustment lines.
Manufacturers in the sector make capacity assignments of production stations at a strategic level and manage the process with long-term investment and capacity planning. In the tactical plans of the companies, the products to be produced are determined and designs are made in accordance with the production lines. Finally, at the operational level, companies focus on using their existing resources in the most efficient way. The most important decisions taken at the operational level are related to production planning and scheduling. 
This study deal with the production of electronic cards for electronic products like television, computer and mobile phone for the proposed model and the application to be made. In the production stations of electronic cards to be mounted on electronic products, there is usually flexible in automatic insertion and full capacity in test adjustment station.
In this study, electronic card production scheduling problems were handled and it was carried out with the motivation to contribute to the efforts to increase efficiency and reduce costs in the electronics sector. The application to be made focuses on the production plan that will respond to the demand and provide maximum benefit in the production and test lines of different types of electronic cards. This problem is in the class of NP-hard optimization problem, where the optimum solution cannot be found in sufficient time. Therefore, for problem solving, a clustering analysis is performed by considering the material usage, material amounts, demands, operation times, stations and process sequences that all electronic cards will visit on the process flow maps at the same time. The resulting clusters are placed into a 0-1 mixed integer mathematical model aimed at the largest production amount for automatic insertion lines. In the final stage, simulation analysis is performed to consider all production stations. In the study, all production stations were taken into account at the same time, taking into account the process flow with an innovative integrated approach. 
At the stage of determining the method of the study, first of all, studies suitable for the problem were examined. Afterwards, the similarities about the problem to be applied and the methods that got the best results were analyzed in detail. The application within the scope of this study for electronic board production scheduling is in the NP-hard optimization problem class, where the optimum solution cannot be found in sufficient time. For this reason, in order to reduce the number of electronic cards and make the problem suitable for the solution, the electronic cards will be clustered according to their similarities, which reduces the preparation time on the SMT lines. In the next stage, the clusters formed will be placed in the working 0-1 mixed integer mathematical model of the multidimensional time axis whose objective function is the maximum production amount. Afterwards, all clusters created to take into account the process flow and the current situation will be analyzed in the simulation model to compare the production numbers of both SMT lines and test setting stations.
When the studies on scheduling problems in electronic card production are examined, it is seen that generally only SMT automatic insertion lines are focused on. This study proposes an approach that takes into account the process flow, considering all production stations, both SMT automatic insertion lines and test adjustment stations. Thanks to the proposed approach, it will be possible to examine the relationship between generation stations and to determine both the bottleneck stations and to reveal the contribution of the actions to be taken to the existing production system. While studies in the literature generally only consider operation times in model proposals, a clustering analysis will be made by considering material diffraction and common material use, material usage amounts, demands, operation times, stations and sequences that all electronic cards will visit in process flow maps at the same time.
In recent years, in studies on scheduling problems in electronic board production, the number of studies that simultaneously perform clustering analysis to reduce preparation times and analyze mathematical model results with simulation in order to test the suitability of proposals for the process flow is quite limited.
The proposed integrated model has been applied for the scheduling of an electronic board manufacturer that produces a wide variety of low-volume products, has hundreds of different products, has multiple surface mount technology (SMT) automatic insertion lines, has multiple process flows, and has multiple test adjustment stations. As a result of the implementation, a 22% improvement was achieved in the production amount by focusing on the production plan that will respond to the demand and provide maximum benefit in the production and test lines, each of which has different characteristics than the other.