Muayenede teknolojik gelişmeler
Technological developments in testing
Yazar: BÜLENT KAYA
Danışman: PROF. DR. AYDIN AYDINCIOĞLU
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü
Derece: Yüksek Lisans, 1992
Konu: Endüstri ve Endüstri Mühendisliği = Industrial and Industrial Engineering
Dizin: Kalite kontrol = Quality control ; Penetrant yöntemi = Penetrant method ; Radyografi = Radiography ; Tahribatsız muayene yöntemleri = Nondestructive inspection methods

Özet:
ÖZET Hazırlanmış bulunan bu tezde, kalite kontrol faaliyetlerinin bir bölümünü teşkil eden tahribatsız muayene kavramı incelenerek, bazı önemli metotlardan söz edilmiş ve kalite kontrol faaliyetleri içindeki yeri ele alınmıştır. Birinci bölümde, kalitenin günlük yaşamımızdaki öneminden söz edilerek bazı kalite tanımları yapılmıştır, Muayenenin öneminden de bahsedilen bu bölümde, kusursuz mamul üretimi için, tahribatsız muayene tekniğinin seri üretim yapan otomatik makinelerdeki uygulaması global şekilde ela alınmıştır. İkinci bölümde, muayene ve ölçme kavramlarından bahsedilmektedir. Muayene çeşitleriyle muayene maliyet inden de bu bölümde söz edilmiştir. Ayrıca ölçme teknikleri ve bu tekniklerdeki gelişmeler ele alınmış ve tahribatsız muayene kavramına yüzeysel olarak yaklaşılmıştır. Üçüncü bölümde, tahribatsız muayene kavramı tarihçesiyle birlikte geniş olarak ele alınmış ve gelişim ini zorlayan nedenler incelenmiştir. Ayrıca hem mühendislik hem de ekonomik açıdan amaçları ayrıntılı olarak irdelenmiştir. Dördüncü bölümde, en. yaygın' olarak kullanılan tahribatsız muayene metotlarından olan, radyografi, radyoaktif izleyici, ultrason, girdap akımları, manyetik toz ve penetrent sıvı metotlarının tanımları ve temel prensipleri verilmiştir. Beşinci bölüm olan sonuç kısmında, konu toparlanarak, teknolojiye paralel şekilde hızla gelişen rekabet ortamıyla, ancak kusursuz mamul üreterek başedilebileceği ve bununda, kalite kontrol faaliyetlerinin bir bölümü olan tahribatsız muayene tekniklerinin kullanılmasıyla sağlanabileceği ifade edilmiştir. vııı

Abstract:
SUMMARY TECHNOLOGICAL DEVELOPMENTS IN TESTING The nondestructive testing concept, which is a part of quality control activities, has been examined in this prepared thesis, and talked about some important methods, and their position has been taken up in the quality control activities. The importance of quality in our daily life has been mentioned in the first part. As it is known, the people can be come face to face with many accidents because of the poor qualityness in their daily life and it is possible that the accidents can cause death, and the life could come in unbearable position. The delayed aeroplanes, unrunning phones, undurable products, broken matches etc... put forward the importance of quality in our daily life. The era of production-quality dilemma has exposed with industrialization and technological development. The people who want the best in every time, bring up the quality problem which belong to everybody. While the Production era remain behind, the quality era has started to make felt its effect increasingly, from the World Warll. up to now. Today the quality concept comprises a large proces which start from customer requirements to end of the life of product. Generally, the purpose of "quality control" is protecting and developing the quality and realize the production with low costs. Briefly it contains all of the operations which are applied before production, during manufacturing and after production stages. Today the testing concept take place in the quality control operations more than manufacturing operations. Making test by the goal of acceptance or rejection is an operation which is done in different stages of manufacture. Testing must be done for zero defect production. The products which are out of standard can be separated quickly by using the nondestructive testing methods on the automatic machines. IXThe cracks and splits ara the most important defects which are meeting while the controlling of the quality of materials during the beginning and manufactur ing stages. They can be detected by various controlling systems which is called nondestructive testing techniques. Being defective of end product can be prevented by using this nondestructive control systems on the fast running automatic systems which produce product or semiproduct. Providing contributions to the economy is quite clear when the zero defect production comes true. In part two, it has been mentioned about the measurement and testing concepts. Today, testing which take place in the quality control activities more than manufacture, constitutes one of the significant part of the total quality control systems. Testing is an action that determines the design specifications if it realizes or not during the production process. Another words, it is an evaluation of any quality characteristics according to its normal standard. Particularly it is benefited from human sense, mechanical and electrical measurement appliance and nuclear techniques. Today, testing isn't thought as an action which set apart the good product from bad. Test making for preventing the constitution of the bad products is the main principle and it gets quite spread. as Testing can be separated into two groups, like 1. Sampling method (accept or reject, and for process control). 2. 100 % testing method (during manufacturing) When the population is not acceptable or the bad products cause high production costs and for the sake of security, the IOQ % testing method is applied. For instance 100 % testing is applied to provide the safety of life on the production process of many medicines and aeroplanes. Naturally testing has a cost. Economical evaluation can be stated according to testing economy : If the testing cost higher than the cost of bad product and there is no another coersive factor, it will not be suitable to make testing. Another affecting point to testing economy is avoided to inspect of unnecessarydefect by means of classifying the faults. Because of that, all the defects that will form in products, are subjected to pareto analysis, then the faults are classified and finali scoring are done par product. The most important concept of testing is measurement. Measurement is the numerization or valuation of the quality characteristics. Today the fast developing measurement technology has put in use the computerized coordinate workbench.. Automatic testing appliance, indirect contact measurement appliance, computer controlled measurement and laser are the some of the various measurement appliances. But the main rule is to obtain the equipment which providing the integration between the low cost and high productive quality systems. We may segregate the measurement operation in to three groups that take place in measurement technology : 1. Dimension measuring. 2. Sensorial measuring. 3. Nondestructive testing (NOT). Nondestructive testing can be defined as a method which does not destroy the product and it is used to detect the cracks and defects on the product and to measure the physical specifications of it. This method has significant developments till today. Some of the main nondestructive testing techniques are eddy current, x-ray, gamma ray, magnetic particle, penetrant dye, ultrasonography, fiber optic and laser. Now the mesurement devices can carry out not only the measurement and classification, on the contrary it shows the measurements' results, to command the process, to make the registrations, calculating, aggregating and filling, in addition to this the devices make the whole works in a good integration* With this development speed it will have been being mentioned very often about the computer supported quality in the next period as became in manufacture and design. In part three, the nondestructive testing concept has been examined and its aims have been taken up by way of engineering and economics. The experiments which do XInot destroy the necessary specifications of material are gathered under the heading of "Nondestructive Testing M. Testing which is being done with nondestructive experiment is an undispensible process of fast production of machine technology. If this techniques are not used, the faults cannot be realized at the beginning and the defective product may be obtained which is discarded. This causes to increase the production costs and the product loses its assurance in the market. The most important economical aim of using nondestructive testing technique is to satisfy the customers. Today, it is obvious that a defective product causes to lose the customer as permanent against the Intensive market competition and it denigrates the name of the firm. Therefore, preventing the faults by using of nondestructive testing is an significant subject by way of market competition. Improvement of the product is also possible with using this techniques. Decreasing the rejection and return ratio is the another economical purpose of the nondestructive testing. To producing product that is going to be discarded at the end, can be prevented by using of nondestructive testing method. This also prevents to inflate the production costs and the lose of time and the labour force. Also it is possible to provide an optimum quality level with this methods; because, after the determination of the product quality, the level of standard can be continued by using of nondestructive experiments. In part four, it has been mentioned about the basic nondestructive testing methods which have been being used widely in the industrial scope. The main methods are radiography, radioactive follower, ultrasonography, eddy current, magnetic particle and penetrent dye. Radiography is a method which gives a film about the detailed internal structure of materials. The main techniques for radiography are the neutrons, gamma rays and x-rays. Radioactive follower technique gives informations about the behaviour of materials. This method has a large scale of application scope in the industry that has given on the table as detailed. XllUltrasonography is based on the acoustics waves which is sent into the materials. The coming echos converge on a point and it evaluates in a computer* This method has an important place in the industrial applications. Eddy current is another method. In which high frequenced alternating current is flowed in a coil to constitute the eddy currents on the surface of the part. Thus the cracks and defects on the surface can be detected. This is a fast - testing method. Magnetic particle method based on the magnetization of the ferromagnetic materials. Thus the surface defects can be determined. A special dye is used in the penetrant method. This dye has the capability to penetrate in every kind of cracks on the material surface. In part five which is the conclusion part, the topic has been recovered and it has been stated that to producing zero defect products is the one way to cope with the competitors under the condition of developing market competition. The necessity of using nondestructive testing methods, have been painted out to producing faultless products and it has been told about the importance for controlling the quality of product on the automatic machine. Moreover it has been asserted that 100 % testing must be done on the every stages of production for producing zero defect products and it has bean also stated that this could be done only by using of nondestructive testing methods. Xlll