Armatür üreten bir işletmede kaplama evresinin kalite güvence kapsamında kontrol optimizasyonu
Control optimisation of plating process in an armature producing company through quality assurance
Yazar: BEHİYE YÜKSEL
Danışman: PROF. DR. YILMAZ TAPTIK
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Metalurji Mühendisliği Ana Bilim Dalı
Derece: Yüksek Lisans, 1997
Konu: Metalurji Mühendisliği = Metallurgical Engineering
Dizin: Armatür = Armature ; Kalite güvence sistemi = Quality assurance system ; Kalite kontrol = Quality control ; Kaplama = Coating

Özet:
Kalite Güvence kavramı, gerek üretim yapan firmalarda gerekse hizmet sektöründe faaliyet gösteren işletmelerde son yıllarda giderek artan bir ilgi görmektedir. Kalite olgusundaki gelişme sonucunda anlaşılmıştır ki kalite, işletmede tek bir departmanın işi değildir, aksine işletmede en üst düzeydeki yöneticiden kapıdaki bekçiye kadar herkesin görevidir. İşletmelerde istenen kaliteyi sağlayabilmek için kalite araç ve teknikleri kullanılarak hata oluşumu azaltılır. Bu tez çalışmasında, armatür ürünlerinin hem korozyondan korunması hemde dekoratif amaçla kaplanması prosesinde kalite tekniklerinden biri olan OHTEA çalışması uygulanarak hata oluşumunu en aza indirmek amaçlanmıştır. Tezin ikinci bölümünde metalik kaplama proseslerinden olan bakır-nikel ve krom kaplamalar üzerinde durulmuştur. Bu bölümde, söz konusu metalik kaplamalar için geliştirilen farklı karakterdeki kaplama banyoları hakkında özet bilgi verilmiştir. Çalışmanın üçüncü bölümünde ise kalite kavramı ve bu olgunun tarihsel gelişimi üzerinde durulmuştur. Bölümün son kısmı ise günümüzde işletmeler tarafından hızla benimsenmeye başlanan "Toplam Kalite Yönetimi"ne ayrılmıştır. Bu kısımda klasik yönetim anlayışı ile benimsenmeye yeni başlanan Toplam Kalite Yönetimi anlayışı arasındaki farklar ortaya konulmuştur. Bir sonraki bölümde ise kalite tekniklerinden biri olan OHTEA detaylı olarak ele alınmıştır. Tezin son kısmı uygulamaya ayrılmıştır. Bu bölümde ürün OHTEA çalışması yapılmıştır. OHTEA çalışmasında öncelikle oluşması muhtemel problemler bir araya getirilmiş, bu hataların müşteriyi nasıl etkileyeceği tespit edilmiş ve hataların oluşmaması için alınması gerekli tedbirler üzerinde çalışılmıştır. OHTEA çalışması sonucunda elde edilen veriler doğrultusunda kaplama ünitesinde proses yeniden oluşturulmuştur.

Abstract:
The aim of this thesis is to realise the control optimization of the coating department of an armature producing company through quality assurance. The thesis consists of four main chapters. In the first chapter, electrolytic coating has been discussed. The second chapter is related to the quality and quality techniques. In the third chapter, failure mode and effect analysis, quality techniques are analysed. These analysis techniques are also used in the practical part of the thesis. In the last chapter is the practical part of the thesis. The details related to these chapters are presented in the following paragraphs. In the first chapter, the results of the literature survey on the electrolytic coating techniques has been presented. Electrolytic coating techniques are the copper, nickel and chromium coating. In the related chapter; copper cyanide bath, bright type nickel bath and decorative type chromium bath that are available in the manufacturing plant which is practical application has been performed are analysed in more detail. The purpose of the coating is to preserve metals against corrosion and give a decorative appeal. In the second chapter, quality concept, total quality management and quality techniques has been explained. The quality concept has been a popular subject all over the world during the last 50 years. Although the first studies on the quality subject had been made in USA, after the Second World War Japanese companies has became the bigger producers of the high quality. The quality concept has been modified during the years parallel to progression in the World Market. The proof of this idea is that the definition of the quality changed from " the conflrmence of specification " to " customer satisfaction ". The historical development of the quality can be summarised in the following order: H1. Control 2. Statistical process control 3. Total quality control 4. Quality assurance The last step of the historical development of the quality concept is the quality assurance. But quality assurance is not the last point to be reached. Although quality assurance certification is necessary for firms, it is not enough for customer satisfaction in today's world market. It is a step to reach the total quality management preferred by today's firms. The base of the total quality management is human. Each people from top level manager to workers in a company are at the same importance. Because of this reason, in the second chapter, the philosophy of the total quality management has been explained. Total quality management is not an aim, it is the way to manufacture well quality product, lower cost, higher quality and termin. A realise these there target at the same time has to produce the product with minimum failure in the shortest period. To obtain these conditions it is necessary to study in an available plant. In this studies, it has been benefited from quality techniques. Because of this, at the end of the chapter, quality techniques has been discussed. In the third chapter, failure mode and effect analysis techniques (FMEA) are discussed in detail. In this part firstly, the definition of FMEA, has been made. The types of FMEA, details of a FMEA application has been presented. A failure mode and effect analysis is an engineering technique used to define, identify, and eliminate known and/or potential failures, problems, errors, and so on from the system, design, process, and/or service before they reach the customer. There are four types FMEA ; system FMEA, design FMEA, process FMEA, service FMEA. A failure analysis technique is one of the most important early protector in design, service and process which will prevent failures and errors from occurring and reaching the customer. There are three important terms in the application of FMEA. They are; 1. Types of failure ; why does not the product work properly? 2. The reasons of the failure ; how does the costumer effect from the failure? 3. The results of the failure; the origin of the failure It is necessary to apply FMEA on time to get satisfactory results. XUA Failure mode and effect analysis is applied in the following cases:. When new system, products, processes or services are being designed,. In the ease of new development in the existing systems, products, processes or services,. If the new application fields can be found for the new systems, products, processes or services. At the fourth chapter of the thesis, product failure mode and effect analysis application has been performed for copper-nickel-chromium coating process. In the application part of the thesis, failure mode and effect analysis which is one the quality techniques has been used to find the failure types which are common in the plant and to supply more quality preventing to form these type failures. In the study, as a first step origins of the failures for copper-nickel-chromium coating process have been investigated. The effect of these type failures on the customers has been analysed. At the last step of the analysis, types of the precautions needed to be taken to prevent failures and errors have been studied. A good FMEA. Identifies known and potential failure modes. Identifies the causes and effects of each failure mode. Prioritizes the identified failure. Prioritizes the identified failure modes according to the risk priority number (RPN)- the product of frequency of occurrence, severity and detection. Provides for problem follow-up and corrective action. In the practical part of the thesis, process failure mode and effect analysis has been applied on the coating procedure of two different products; zamak and brass. Before the failure mode and effect analysis, to determine common failure types pareto analysis has been conducted. According to the results of the pareto analysis, the following common failure types has been determined: roughness, bad covering, grey plating, pitting, dull coating. In the failure mode and effect analysis, subsequent failure types has been selected with the assistance of the pareto analysis. Depends on this analysis, important failure types are roughness, bad covering and grey plating. The main reason for the roughness type failure observed in the plant, is used casting sand. In the FMEA, the first failure type to be examined is roughness. Lack of some equipments such as ultrasonic degreasing and filtration which are to be used to prevent the roughness type failures. Bad covering and grey plating types failure has been analysed. X1UIn this chapter, the first FMEA has been done for zamak. Firstly, possible failure types can occur in each plating steps during the copper-nickel and chromium coating of zamak has been ordered. After that, the reasons of these failures have been discussed. At the following step, the possible results when these type failure occurred have been defined. At the end of these steps, the first part of the FMEA chart has been filled up. For the bad covering failure type, it has been found that the risk priority number (RPN) must be greater than 50. Also it has been defined that which type of precautions can be applied to decrease the amount of the failure. After the application of these precautions, the second part of the failure mode and effect analysis chart has been filled up and the number of the risk priority number (RPN) for the bad covering failure is very small compared with 50. Thus bad covering type failure has been stopped. The same analysis steps have been applied for brass products. At the end of the forth chapter, some photographs of the failure types are presented. The following failures from FMEA application has been obtained: roughness, bad adhesion, dull coating, grey coating, pitting. The reasons of this failures are the followings: Lack of filtration Anode sludge existing in the solution Solid particles in the coating bath Bath concentration is out of control Insufficient cleaning, pickling and rinsing before coating process Metallic contamination available in the coating bath Organic contamination available in the coating bath High electrical current density during the coating process These are the measures to prevent the occurrence of this type failures: Copper and nickel baths have to be filtered, analytical studies have to be performed with the samples that represent coating bath, baths have to be cleaned periodically against metallic and organic contaminetion. Sufficient electrical currency have to be supplied during the coating process. To check the metallic coating for the elimination of failures, following simple checks can be done, adhesion,abrasive, coating thickness, control with eyes. The aim of this study is to define that quality can not be supplied by controlling of product during the process. XIVThe quality have to be produced during process. Because of this reason, process must be under controlled. Quality tools and techniques for the total quality management are to be used to solve the problems and to development continuously. The trio of high quality, low cost and termin can be reached using the controlled processes. XV