Taguchi deney tasarımı metodu ile alüminyum ekstrüzyon proses parametrelerinin optimizasyonu
Optimization of aluminum extrusion process parameters with Taguchi experimental design method
Yazar: ZEKİYE AKSU
Danışman: DR. ÖĞR. ÜYESİ VEDAT TEMİZ
İstanbul Teknik Üniversitesi / Lisansüstü Eğitim Enstitüsü / Makine Mühendisliği Ana Bilim Dalı / Konstrüksiyon Bilim Dalı
Derece: Yüksek Lisans, 2024
Konu: Makine Mühendisliği = Mechanical Engineering

Özet:
Solar enerji kullanımının artmasına ve kısa vadede daha da artacağının bilinmesine paralel olarak, pazar talebine optimum proses verimliliği ile yanıt verebilmek için solar enerji panellerinin montajında kullanılan alüminyum profilin üretim sürecinin istatistiksel yöntemlerle optimizasyonu gerekliliğine istinaden bu çalışma gerçekleştirilmiştir. Alüminyum profilin ekstrüzyon yöntemi ile üretim sürecindeki proses parametreleri, ürünün kalitesine dolayısıyla hat verimliliğine doğrudan etki etmektedir. Alüminyum ekstrüzyon ürününün kalitesini ve dolayısıyla proses verimliliğini optimize etmek için, tekil proses parametrelerinin ve proses parametrelerinin birbiri ile etkileşiminin, proses çıktılarına etkisi ileri istatistiksel analiz yöntemleri ile değerlendirilmiştir. Taguchi deney tasarımı ile alüminyum ekstrüzyon proses verileri analiz edilmiş olup, hedeflenen proses çıktı faktörleri için seçilmesi gereken optimum proses giriş faktörleri tespit edilmiştir. 
Alüminyum ekstrüzyon proses kalitesine etki edebilecek faktörler; ekstrüzyon profil hızı, kütük (billet) sıcaklığı, kalıp sıcaklığı, kütük (billet) tipi,  ekstrüzyon sıcaklığı, ekstrüzyon basıncı, metalurjik değişkenler, ekstrüzyon oranı, kalıp tasarımı ve yağlama sistemleri olarak analiz edilmiştir. Hammadde olan kütük (billet), spektrometre analiz sonuçları ile tedarik edilmektedir. Dolaysıyla metalurjik olarak proses girdisi kontrol altındadır. Aynı profil kalıbı ve aynı ölçülerdeki kütük (billet) ile, yağlama sistemi kalibre edilmiş durumda yapılan istatistiksel proses optimizasyonu için, üstte sıranmış olan ilk altı faktör dikkate alınmıştır.
Taguchi deney tasarımında ekstrüzyon profil hızı (mm/sn), kütük (billet) sıcaklığı (°C), kalıp sıcaklığı (°C) ve kütük (billet) tipi kalite karakteristiğini doğrudan etkileyen bağımsız deney faktörleridir. Ekstrüzyon sıcaklığı (°C) ve ekstrüzyon basıncı (MPa) ise bağımsız değişkenlerin değer kombinasyonlarına göre değişen bağımlı değişkenlerdir.
Değişken seviyeli Taguchi Deney Tasarımı için, 8 test üretimi gerçekleştirilmiştir. Test üretiminin sonuçları için Taguchi S/G (sinyal gürültü oranı) ve ortalamalar grafikleri analiz edilmiştir. Ekstrüzyon sıcaklığı (°C) ve ekstrüzyon basıncı (MPa) bağımlı değişkenleri için regresyon analizleri yapılmıştır. R-sq (determinasyon katsayısı) değerlerine göre istenen anlamlılıkta deney modelleri elde edilmiştir. Prosesin; kalite karakteristikleri dikkate alınarak optimize edildiği bağımsız değişkenler Taguchi analizi ile hesaplatılmıştır.
Anahtar Kelimeler: Alüminyum, Ekstrüzyon, Taguchi, Kalite, Optimizasyon

Abstract:
In addition to the use of aluminum profiles in the assembly of various construction systems in the automotive and construction sectors, they are also used in large volumes in the assembly of solar energy storage systems. In parallel with the increase in the use of solar energy and the knowledge that it will increase further in the short term, this study was carried out based on the need to optimize the production process of the aluminum profile used in the assembly of solar energy panels with statistical methods in order to respond to the market demand with optimum process efficiency. Taguchi defined the stages of system design, parameter design and tolerance design as the steps to ensure quality in process design, and stated with this studies that the most decisive studies in improving product quality are obtained at the parameter design stage. Based on this starting point, it is aimed to make optimal adjustments for the process parameters that can be controlled by process parameter design in the aluminum extrusion process and to determine the optimal process values. In order to obtain a robust process parameter design, it is aimed to first correctly determine and monitor the controllable factors (parameters) in the process and choose their values optimally. In this way, the process output will be minimally affected by uncontrollable factors, and repetitive production can be achieved by minimizing variation with the determined optimum values of controllable factors. Statistical experimental design method, which is the most effective method, was used in parameter optimization for many process parameters, which not only affect the result individually, but also their interactions with each other may have a different effect on the result. Process parameters in the production process of the aluminum profile with the extrusion method directly affect the quality of the product and therefore the line efficiency. In order to optimize the quality of the aluminum extrusion product and therefore the process efficiency, the effects of individual process parameters and the interaction of process parameters on the process outputs were analyzed with advanced statistical analysis methods using the design of experiments method. Aluminum extrusion process data were analyzed with Taguchi experimental design, and the optimum process input factors that should be selected for the targeted process output factors were determined.
Factors that may affect aluminum extrusion process quality; extrusion profile speed, billet temperature, mold temperature, billet type, extrusion temperature, extrusion pressure, metallurgical variables, extrusion rate, mold design and lubrication systems were analyzed. The raw material, billet, is supplied with spectrometer analysis results. Therefore, the process input is under metallurgical control. Since production is made with the same profile mold and billet of the same diameter, the extrusion rate is not a variable for the project. Since the lubrication system is also calibrated, it has been determined as a constant factor for the project.

In the Taguchi experiment design, extrusion profile speed (mm/sec), billet temperature (°C), mold temperature (°C) and billet type are independent experimental parameters that directly affect the quality characteristic. Extrusion temperature (°C) and extrusion pressure (MPa) are dependent experimental parameters that vary according to the value combinations of the independent variables.
With the beginning and widespread use of experimental design in the manufacturing sector, many computer programs have been written on this subject. In this project, the creation of the experimental design, analysis of signal-to-noise ratios, analysis of averages graphs, regression analysis, and result prediction sections were carried out using the Minitab program. Thus, all analyzes were completed at high speed. The interfaces used in the program are explained in detail in the report.
For the variable level Taguchi Experimental Design, 8 tests were produced. The signal-to-noise ratio, which is an important performance criterion in experimental design, was calculated in parallel with the target of the profile exit temperature and pressure values, where the smallest is the best. Taguchi S/G (signal to noise ratio) and averages graphs were analyzed to interpret the data obtained as a result of test production. It has been determined that billet temperature and profile speed, which are independent factors, have a very strong statistical effect on the profile exit temperature. It has been determined that profile speed has a very strong statistical effect on pressure and mold temperature has a borderline statistical effect. In order to analyze the actual output of the process, the profile exit temperature and pressure factors were taken together and the signal-to-noise ratio and average graphs were examined. A very strong statistical relationship was determined between the process output parameters of profile outlet temperature and pressure and the process input parameters of billet temperature and profile speed. This strong level of statistical significance was confirmed by regression equations. Regression analyzes were performed for the dependent variables extrusion temperature (°C) and extrusion pressure (MPa). R-sq (coefficient of determination) in the regression equation used to calculate the profile exit temperature was determined as 95.46 %, and R-sq (coefficient of determination) in the regression equation used to calculate the pressure was determined as 81.07%. It is seen that experimental models with the desired significance are studied according to R-sq (coefficient of determination) values.
The aim of the project was to find the process input values that needed to be defined in order to obtain the process output values and thus minimize the variation. In parallel with the purpose, in order to obtain the targeted pressure and profile exit temperature, the profile speed, billet temperature and mold temperature that should be defined for the process were determined. In addition, equations that predict the profile outlet temperature and pressure parameters that will occur at the process output in case of production with the selected independent variables have been obtained.
In this period when many manufacturers produce the same product and strive to reach potential customers, being preferable as a manufacturer of products of equal or higher quality is mostly about being competitive in terms of price and speed. Being competitive in product prices while maintaining our profit margin is related to minimizing losses and being able to produce repetitively with the optimum design of process and product parameters.
In the project, high significance level regression equations were obtained for the aluminum extrusion process by using the Taguchi experimental design methodology, and process input parameters (independent variables) that would provide the process outputs at optimum parameters were determined.
Key Words: Aluminum, Extrusion, Taguchi, Quality, Optimization