Hassas Dökümde Kalite Teknikleri Ve Hata Analizleri

Abstract

Bu çalışmada, hassas döküm yönteminden ve avantajlarından, kalite ve maliyetlerinden, döküm hatalarından ve oluşma nedenlerinden, problem çözme tekniklerinden, hassas döküm yönteminin uygulandığı bir firmadan proses sırasında meydana gelen uygunsuzlukların çözümünde kullanılan kalite system araçlarının bir kısmından örnek uygulamalar verilerek anlatılmıştır ve ortaya çıkan sonuçlar değerlendirilmiştir.

Investment casting by the lost wax process has been used for centuries for casting statues and other art castings and this is still its main outlet in the bronze foundry industry. It is also a process worth considering where complex, high precision components are required as it offers the opportunity to make by a single casting an object that might otherwise entail difficult and expensive machining or a welded or brazed assembly. The process uses a pattern of wax or other low melting point material which has itself to be cast in a mould, although it may be built up from several parts. The pattern is invested with a refractory slurry several coatings being applied to build up a shell of adequate strength. The pattern is then melted out of this shell which is baked to strengthen the bonding of the refractory and remove moisture. It is then ready for casting. Casting defects are undesirable in critical structural areas and on surfaces. Minor defects that would not be particulary noticeable can become quite obvious after surface treatment. Various defects can occur in manufacturing processes, depending on factors such as materials, part design, and processing techniques. While some defects affect only the appearance of parts, others can have major adverse effects on the structural integrity of parts made. Several defects can develop in castings. For example; gas porosity, hot cracks, misrun, slag, cold shut. Problem solving techniques are used for detecting and solving problems caused by defaults that are already occurred or might be occurred. In these master thesis, the investment casting method and its advantages, quality, casting defects and their reasons, problem solving techniques and concerning examples and results will be discussed.