Bir dişli pompa grubunun imalatında eşzamanlı mühendislik ve grup teknolojisi

Abstract

Bu çalışmada eşzamanlı mühendislik kavramı içerisinde grup teknolojisi matris esaslı yöntemlerden ROC (Rander Order Clustering Method) Derece Sıralamasıyla Kümelendirme Metodu kullanılarak bir fabrikada imalatı yapılan dişli pompa grubuna uygulanmıştır ve yeni fabrika düzeni oluşturulmuştur. Bir ürünün tüm evrelerini üretim araçları kullanarak tasarlayan mühenlisliğe CE ( Concurrent Engineering) Eşzamanlı Mühendislik denir. Eşzamanlı mühendisliğinin amacı kalite, saha-destek kapasitesi ve üretim kapasitesi eşzamanlı olarak gelişirken tasarımı detaylandırmaktır. Bu CE'yi gerçekleştirmek için çok disiplinli takımlar kullanan metodlar içerir: Algoritma, teknik ve yazılım formundaki CE araçları ve uzmanlık ve bütün tasarımı ve üretim sıralamasını oluşturan insanların yargısı. CE'nin esası ürün tasarımının ve işlemlerin planlanmasının ortak tek bir aktivitede birleştirilmesidir. Eşzamanlı tasarım, erken tasarım kararlarıyla kaliteyi geliştirmeye yardım eder ve ürünün maliyetine büyük bir etkisi vardır. CE ürünün bütün hayat süreci boyunca (yapımından hurdaya kadar) maliyet ve kalitesini değerlendiren tekniklerin karışımının uygulamasıdır; bu teknikler aşağıda verilmiştir. l.Aksiyomatik tasarım 2.İmalat amaçlan için tasarım 3. Tasarım bilimi 4.Montaj tasarımı 5.Güçlü tasarım için Taguchi Metodu ö.İmalat sürecindeki tasarım kuralları 7.Bilgisayar destekli DFM 8.Grup teknolojisi 9. Yetersizlik durumu ve etki analizi 10.Değer mühendisliği Hücresel İmalat (Hİ) Sistemlerinin Modern İmalat Sistemleri arasında önemli bir yeri vardır. Bir üretim sisteminin yapısı uygun olduğu takdirde, Hİ verimliliği önemli ölçüde arttıran bir sistem olmaktadır. Klasik üretim sistemlerinden başlayıp esnek üretim sistemlerine kadar uzanan geniş bir yelpaze uygulama imkanı bulmaktadır. Kümelendirme yöntemleri ve üretim sistemleriyle ilgili özelliklerin çok sayıda olması, Hİ'nin uygulanacağı üretim sistemi şartlarına göre uygun bir yöntemin seçilmesini ve uygulanmasını zorlaştıracaktır. Hİ Sistemi tasarımı 5 aşamadan oluşur. 1. Parça nüfuzlarının seçimi ve parçaların ailelere gruplandırılması, 2. Makina ve proses nüfuzlarının seçimi ve hücrelere ayrılması, 3. Takımların, paletlerin ve tertibatların seçimi, 4. Malzeme taşıma ekipmanının seçimi, 5. Ekipman yerleştirilmesi. SUMMARY THE CARRYING OUT OF GROUP TECHNOLOGY IN THE CONCURRENT ENGINEERING CONCEPT ON A FACTORY WHICH IS MANUFACTURING GEAR POMP In this study in the concurrent engineering concept by using ROC algorithm, which is one of the matrix based methods of group technology is carried out on a gear pomp group in a factory and a new factory order is made. Design may be defined as "all activities which transform a collection of inputs into a product satisfying a need ". In a more global sense, design is the combination of processes, both economic (as in marketing) and technical (as in machining), that convert raw materials, energy, and purchased items into components for sale to another manufacturers or into end products for sale to the public. We know that this process can be measured, managed, and improved. Measures of design include functional performance, production cost, production time, and maintainability. We manage the process by using documentation including engineering drawings, analysis results, and meeting among experts in manufacturing, assembly, quality control, finance, and marketing. Often, however, these experts do not communicate often enough, nor is the interaction efficient. It may be that the manufacturing experts are called in after the design is finalized. In fact, that is the typical and traditional approach to manufacturing planning. The design is "thrown over the wall" separating the design and manufacturing departments, and the manufacturing experts then have to figure out a way to make a part for which they had no input during the design stage. The same barrier exists between the designer and experts in assembly, field maintenance, quality control, marketing, and other subgroups in a manufacturing facility. The traditional design process is a serial process in which the design is passed through the various modules; should a design change be necessary, the design is returned to the top and the process is repeated. Note that the marketing experts give their needs to the designers, who determine product specifications, and in turn, send their product design to the manufacturing experts, who specify the production system to make the design. The manufacturing experts get input from production systems experts and make decisions on purchasing new equipment based on their return on the investment. Then, the production system is designed and production cost is calculated. The input at the top, therefore, is a set of marketing needs, and the output at the bottom is production cost. If the cost is too high, then the process must be repeated by modifying the design at one of stages. The various domain experts are almost always located in physically separate departments, and communication among them is sometimes difficult. Modifications may be made in the product design or in the process design. There are usually many ways to manufacture a

In this study in the concurrent engineering concept by using ROC algorithm, which is one of the matrix based methods of group technology is carried out on a gear pomp group in a factory and a new factory order is made. Design may be defined as "all activities which transform a collection of inputs into a product satisfying a need ". In a more global sense, design is the combination of processes, both economic (as in marketing) and technical (as in machining), that convert raw materials, energy, and purchased items into components for sale to another manufacturers or into end products for sale to the public. We know that this process can be measured, managed, and improved. Measures of design include functional performance, production cost, production time, and maintainability. We manage the process by using documentation including engineering drawings, analysis results, and meeting among experts in manufacturing, assembly, quality control, finance, and marketing. Often, however, these experts do not communicate often enough, nor is the interaction efficient. It may be that the manufacturing experts are called in after the design is finalized. In fact, that is the typical and traditional approach to manufacturing planning. The design is "thrown over the wall" separating the design and manufacturing departments, and the manufacturing experts then have to figure out a way to make a part for which they had no input during the design stage. The same barrier exists between the designer and experts in assembly, field maintenance, quality control, marketing, and other subgroups in a manufacturing facility. The traditional design process is a serial process in which the design is passed through the various modules; should a design change be necessary, the design is returned to the top and the process is repeated. Note that the marketing experts give their needs to the designers, who determine product specifications, and in turn, send their product design to the manufacturing experts, who specify the production system to make the design. The manufacturing experts get input from production systems experts and make decisions on purchasing new equipment based on their return on the investment. Then, the production system is designed and production cost is calculated. The input at the top, therefore, is a set of marketing needs, and the output at the bottom is production cost. If the cost is too high, then the process must be repeated by modifying the design at one of stages. The various domain experts are almost always located in physically separate departments, and communication among them is sometimes difficult. Modifications may be made in the product design or in the process design. There are usually many ways to manufacture a XI product, and the process actually selected depends on product function, dimensions and tolerances, avaible equipment, and cost. Addressing all products aspects including cost during the design stage is a new approach to design that has been termed " design for manufacturing: getting it right the first time, "or" concurrent engineering (CE), or "strategic approach to product design (SAPD)." What we will call concurrent engineering (CE) has evolved by thinking about all tasks as elements in an integrated design. The difference between traditional design techniques and CE is that these tasks are performed, not by individual specialized groups, but by one multidisciplinary team of experts or a team of teams in which each domain expert has equal say in the design. Concurrent engineering has as its purpose to detail the design while simultaneously developing production capabilitiy, field-support capability, and quality. It consists of methodology using multidisciplined teams to carry out this concurrency: CE tools in the form of algorithms, techniques, and software, and the expertise and judgment of people who make up the complete design and production sequence. The essence of CE is the integration of products design and process planning into one common activity. Concurrent design helps improve the quality of early design decisions and has a tremendous impact on life-cycle cost of the product. The designer, represented by the hub of wheel, coordinates the comments and redesign suggestions from each of the domain experts around the circumference. Communication among the experts is indicated by circumferentiel arrows. In this design procedure, a conceptual design is presented radially to the group of experts, at which time each can comment on the design relative to his or her own area. Assembly experts consider assemblability problems, process planning experts consider the process sequence, metal removal experts consider the avaible machine tools, new removal techniques, and the requirements of design, and so on. The number of domain experts around the rim varies, but the typical domains are:. Assembly. Fabrication. Inspection. Field maintenance. Marketing. Domain-specific engineering functionality These experts have the mission to conceptualize the product and optimize it until a consensus agreement is reached on the functionality, producibility, and cost constrains. The design moves from the designer out to the experts, who discuss it and suggest design chances to satisfy these three constrains. The design is then passed back to the designer, who resolves conflicts in the suggested changes, modifies the design, and sends it out again for evaluation. Hopefully, the design will need fewer and fewer changes on each iteration until it finally arrives back at the designer with no new redesign suggestions. At this point, the design is considered to be feasible and, in all probability, somewhat optimized. One can think of CE as accomplishing this purpose using five interrelated elements: Xll 1. Careful analysis and understanding of the fabrication and assembly process. This allows the designer to predict the performance of the product and select production schemes from among alternative processes. 2. Strategic product design, conceived to support a specific strategy for making and selling the product. The product should be made to marketing specifications for market value, shelf life, and usability. 3. Rationalized manufacturing systems design coordinated with product design. 4. Economic analysis of design and manufacturing alternatives to permit rational choices among design alternatives. 5. Product and system designs characterized by robustness means resistance to unpredicted noise or errors in production and function. In other words, the product function is as possible to variations in dimensions within the tolerance. The goals of CE within these elements are:. Avoiding component features that are unnecessarily expensive to produce e.g., specification of surfaces smoother than necessary, wide variations in wall thickness of an injection-molded component, too-small fillet radian in a forged component, or internal apertures too close to the bend line of a sheet metal component.. Minimizing material costs or making the optimum choice of materials and processes e.g., can the component be cold-headed and finish machined rather than machined bar stock? The actual implementation of CE involves human relations and organizational and institutional arrangements which are now only dimly perceived. Many observes are convinced that these concerns outweigh the importance of technology in CE. Here is a combined list of goals which are considered in the concurrent design process. 1. From the start, include all domains of expertise as active participants in the design effort. 2. Resist making irreversible decisions before they must be made. 3. Perform continuous optimization of product and process. 4. Identify product concepts that are inherently easy to manufacture. 5. Focus on component design for manufacturing and assembly. 6. Integrate the manufacturing process design and product design that best match needs and requirements. 7. Convert concept to manufacturable, salable, usable design by stating all constrains. 8. Anticipate fabrication and assembly methods and problems. 9. Reduce number of parts. 10. Increase interchangeability between models. 1 1. Define subassemblies to allow models to differ by subassemblies. xm 12. Standardize fastener types and sizes; use low-eost, irreversible fasteners only where a skilled serviceperson would work. 13. Improve robustness of product and process. 14. Identify difficult processes steps for which costs and process times cannot be predicted. 15. Use existing process and facilities so that product yield is high. 16. Adjust tolerances to eliminate failures during assemly. 17. Identify testable areas. 18. Make assembly easier by miriimizing setups and reorientations. 19. Design parts for feeding and insertion. 20. Determine character of product; what design and production methods are appropriate. 21. Subject the product to product function analysis to ensure rational design. 22. Carry out design for producibility and usability study, can these two-ilities be improved without impairing function? 23. Design fabrication and assembly process. 24. Design assembly sequence. 25. Identify subassemblies. 26. Integrate quality control strategy with assembly. 27. Design each part so that tolerance are compatible with assembly method and fabrication costs are compatible with cost goals. 28. Design factory system to fully involve production workers in the production strategy, operate on minimum inventory, and integrate with vendor capabilities. Many schemes have been divised to take care of all the guidelines listed above. Each of these schemes has a common concern: measuring design quality. Quality can be expressed as in the guidelines, such as number of parts, ease of assembly, size of tolerances, functionality, etc. Measurement of design is the key to CE the design itself is considered to be complete when all domain experts sing off on it. That means that each measure of design completeness or sufficiency or quality has been satisfied. Concurrent engineering is the application of mixture of these techniques to evaluate the total life-cycle cost quality. 1. Axiomatic design. 2. Design for manufacturing guidelines. 3. Design science. 4. Design for assembly. 5. The Taguchi method for robust design. 6. Manufacturing process design rules. 7. Computer-aided DFM. 8. Group Technology. 9. Failure-mode and effects analysis. 10. Value engineering. Cellular Manufacturing System (CMF) Design is a very difficult study, because too many manufacturing data should be evaluated and manufacturing system conditions are rather variable from one company to another. Also, most of these data XIV are ill-structured and requires experts, knowledge and experience. The Clustering Algorithms are data dependent and does not exist the best one for every type company. The most important stages are early stages of CMF design. Cellular Manufacturing (CM), has an important role in manufacturing industry. CM gained a great popularity after Flexible Manufacturing Systems (FMS) were introduced. However, it can be applied in conventional manufacturing. The concept of Group Technology (GT) leads to formation of part families that are similar in design or manufacture. The machines required to produce a part family are groupped together in a manufacturing cell. Cell formation is the first, and the most important phase on GT application. This initial decision influences all other decisions involved in the design of Cellular Manufacturing (CM) Systems. The following methods for cell formation in GT have been studied mainly:. Traditional manufacturing systems.. Cluster analysis and group technology.. Factory layout.. Part families problem in GT and forming of machine groups.. The operation order of clustering.. Basic methods of GT.. Clustering problem of GT.. ROC (Rank Order Clustering Method) Compared with functional layout in a job shop, the results of successful application of GT in manufacturing ensure as follows: 1. Reduction in machine set-up times. 2. Smooth work flow due to the possibility of small batch manufacturing. 3. Reduced work-in-process inventories. 4. Reduction in throughput times. 5. Reduction in handling costs. 6. Simplification in production planning and control. 7. Reduction in tooling investment. 8. Unification of responsibilities. 9. Increased quality. 10. Improved human relations. 1 1. Reduced paper work. 12. Automation; GT is the first evolutionary step in automation. All of these advantages are mainly realized by simplifying the work flow in machine flow in machine shop applied to GT principles. However, some disadvantages occur in GT. The major disadvantages are: 1. Extensive analysis, along with the accompanying difficulties in the selection of the appropriate methodology, is required for the formation of part families and machine groups. xv 2. The purchase of additional machines may be required in order to realize the gains inherent in the cell structure. 3. Chu concluded that the multitude of clustering algorithms, clustering criteria, and measures of performance make it difficult to evaluate and select a proper or better clustering method. 4. Different clustering criteria may produce different groupping results even if the same algorithm and data are used. 5. Although minimizing the number of exceptional elements has been widely used as a measure, their appropriateness is not proven. 6. The determination of an optimal number of manufacturing cells is a controversial issue. As a practical work, by using GT ROC (Rander Order Clustering Method) algorithm a gear pomp manufacturing in a factory is converted into clustering manufacturing from the classic factory order. At first, the operation sequence of the components determined and thereafter machine component matrix is composed. Then classification by looking and lastly a new factory order is formed by using ROC algorithm.