İmalat sektöründe kalite güvencesi ve proses kontrol sistemlerinin belirlenmesi /
Yazar: FUNDA KAHRAMAN
Danışman: PROF.DR. O. TUĞRUL GÖNCEL
Çukurova Üniversitesi / Fen Bilimleri Enstitüsü / Makine Mühendisliği Ana Bilim Dalı
Derece: Doktora, 1994
Konu: Makine Mühendisliği = Mechanical Engineering
Dizin: ISO 9000 = ISO 9000 ; Kalite güvence sistemi = Quality assurance system ; Kalite kontrol sistemi = Quality control system ; Toplam kalite yönetimi = Total quality management ; Üretim endüstrisi = Production industry

Özet:
- 277 - ÖZET Günümüzde pazarda yeralan ürün ve hizmet tercihinde %80 oranında kalitenin etken olduğu koşullar geçerliliğini sürdürmektedir. Hedeflenen kalite düzeyine ulaşmak için temel araç olarak Kalite Güvence Sistemi'nin oluşturulması gerekmektedir. KGS, bir ürünün elde edilmesindeki tüm aşamalarda kaliteli üretimi gerçekleştirmeye yönelik çalışmaları kapsar. Bir ürün için ön görülen ve gerekli olan kalite düzeyini tasarımdan başlayarak her aşamada kalıcı olarak sağlanmasındaki etkinliklerin tümüdür. KGS'nin oluşturulmasında gözönüne alınacak noktalar, organizasyon, denetim, planlama, dokümantasyon, düzeltme faaliyetleri, tasarım kontrolü, ölçü cihazlarının kalibrasyonu, istatistiksel teknikler, giriş ve proses kontrolü, uygun olmayan malzemelerin kontrolü, taşıma-depolama-ambalajlama, eğitim ve motivasyondur. Bu çalışmada, kalite kavramının zaman içinde gelişimi çerçevesinde bugün ulaşılan KGS'i anlayışı incelenerek işletmelerin kalite olgusuna sistematik yaklaşımların sağlayacağı yararlara değinilmiştir. Burada amaçlanan, orta ölçekli işletmelerde KGS'nin kurulması ve yürütülmesi aşamalarında yönlendirici bir rol oynamaktır. Bu amaç doğrultusunda, KGS'nin kurulabileceğini örneklemek amacıyla bu kategoriye giren orta ölçekli bir işletme olan X Döküm A.Ş. model olarak seçilmiştir. Temelde KGS'nin kurulması için gerekli olan Kalite Güvencesi El Kitabı ve Prosedürlerdir. ISO 9002 ve Kalite Güvencesi Manueli baz alınarak, KG'nin dokümantasyon kısmı hazırlanmıştır. îstatistiksel Proses Kontrol'un dökümhanelerdeki uygulamalarına örnekler verilmiş ve sonuçlar irdelenmiştir. Kısaca, KGS kalitede işletmeleri mükemmelliğe ulaştıracak olan bir yönetim felsefesidir ve rekabet koşullarında başarılı olmanın tek yoludur.

Abstract:
278- SUMMARY In today's life, the product, which takes place in market and service preference, the circumstance which are effective about 80% quality rate, shall prolong its validity. To reach the purposed level as a principal tool the Quality Assurance System's (QA) formation is being required. The Quality Assurance System includes the entire works in all level to have long-lasting product as well the necessary quality level for the product must also take place in all steps from the project to other effectivenesses. The points which will be considered during the formation of the QAS are the project, planning, documentation, reform/correction activities, the calibration of the measurement and test equipments, the statistics control technics, input and process control of the improper materials / supplies, carrying, storing, packing, training, motivation and inspection. Quality assurance concepts aroused as a result of the need of better quality in many industries after the Second World War, and now it is a unrenouncable necessity in a vast majority of industries. In the case of casted parts concept and reliability of quality requires to deal with assurance of quality in a larger scale. Cast quality is affected by many factors such as design, materials, operator etc. This complicated structure of cast quality, requires control of all these factors and this consititutes the concept of quality assurance. Identification and elimination of defect by quality control, reduces the failure costs which may be caused by defects. The incentive for manufacturers to reduce defects, and therefore costs, led to extensive development of quality control concepts. Generally concept of quality assurance includes all activities to obtain desired quality of the product. This includes suitability studies of all possible applications to standards by using plans and previous service experience. It is especially important to select suitable material and qualified operator to achieve quality assurance of casted parts following factors also explains the necessity of quality assurance:279- -It may not be possible to eliminate failures occured during service conditions by quality control tests and inspections. -It is necessary to design or constitute quality - Defects can be identified in inspected specimens but non-inspected specimens may include defects too. -It is more expensive to repair defected parts than to produce them. Quality forms the base of quality assurance, and more effective control of quality may be done by people who are familiar to product or production. The responsibility of the product belongs to the producer. This approach has been developed especially after 1980 at many countries and industries. Thus responsibility of defects caused from design and production is attributed to producer. Assuming that top management is comitted to a quality policy and all of it's obligations, certain initial steps would be sensible. A manufacturer must first determine where quality problems are accurring (using pareto analysis), e.g. design and specification, procurement, material, manufacture, inspection. The significance of the individual must be considered. Casting introduces particular problems, e.g., whilst designer and engineers are professional qualified and trained. Workers and operators rely more and personal skills. The results of these eforts are judged by others who may have inadequate training or experience to take the critical decisions required of them. Studies aimed to develop quality, requires obligatory sanctions for the purchaser and suppliers. This should result, purchaser and suppliers have to encourage developments and studies for obtaining better performance for product through its economic life. Factors to define quality levels of casted parts should be settled by co-operation of design engineers and quality controllers. To settle better quality than the service requirements may cause economic loss. Thus, it is necessary to settle an optimum quality level due to service condition, and it can be done by optimization contractive and functional conditions.-280 To be effective, all the corporate activities which affect the quality of the product or service must be adequately planned, coordinated and controlled, in other words, these activities must be properly "managed". To manage the quality functions effectively, corporate management must establish: -a corporate "Quality Policy" for defining the overall quality objectives, -a corporate "Quality Plan" for implementing the policy and -a corporate "Quality System" for implementing the plan. These provide the basis for an effective, systematic and planned approach to the corporate management of quality. Since the early 1970's, an increasing number of developed countries have recognized the need for a national standard to define the requirements for an effective corporate "Quality Systems". As more and more countries developed and implemented their own national "Quality Systems" standards, it became clear that the differing national requirements where causing technical barriers to trade. Thus, the need for an International standard for quality systems became apparent. International Organization Standardization (ISO), a series of five related International Standards was published in 1987. These five ISO Standards provide a basis for harmonizing the national "Quality Systems" standards throughout the world. However, it must be born in mind that it is very difficult to develop a single set of "Quality Systems" requirements which are suitable for all industries and all types of enterprises in all countries. It may therefore be necessary to adapt the ISO requirements to particular needs. ISO standards relating to "Quality Systems" are given follows: ISO 9000 - Quality management and quality assurance standards-Guide to selection and use ISO 9001- Quality Systems-Model for quality assurance in design/development, production installation and servicing281 - ISO 9002 - Quality Systems-Model for quality assurance in production and installation ISO 9003 - Quality Systems-Model for quality assurance in final inspection and test ISO 9004 - Quality management and quality system elements-Guidelines. These ISO standards are being increasingly adopted at the regional level and at the national level. In this study the quality concept's development guideline within the time period, the QAS idea has been examined and advantages, which shall be provided by the factory's systematical approach to the quality concept, discussed too. QAS study generally take place in the large leveled company. Despite the fact that, the large companies try out hard enough to inform medium level companies, which provide subproduct for them, about the quality level that is still needed to have more information for the QAS. For the purpose of showing that QAS can be established and operated in the medium leveled companies entering this catagory the X' Casting Ind.& Tra. Company has been selected from among above mentioned companies as an example. Quality Assurance Handbook and Procedures are initially needed to establish the QAS's documentation part has been prepared by basing on the ISO 9000 Series Standards and Quality Safety Manual. The Statistical Process Control Technics (SPC) have been applied in the foundry of X' Casting Company and the results were scrutinized. After certificate and field inspection, it has been defected that the application of the QAS provides advantages for this company. As a result, the Quality Assurance System, reference the quality is a most reliable factory philosophy to take those companies to perfection plus it is the only way of being succesfull.