Hücresel imalat sistemleri tasarımı ve uygulaması

Abstract

Günümüzde bir çok kuruluşun başarısı uluslarası piyasalardaki rekabet gücüyle ölçülmektedir. Dünya çapındaki bir üretici olmak için modern üretim yöntemlerini kullanmak alternatif olmaktan çıkmış zorunluluk haline gelmiştir. Birinci bölümde, genel olarak imalat sistemlerinin tanımı yapılmış ve..Geleneksel Üretim Sistemleri,..Çağdaş Üretim Sistemleri olarak İM grupta toplanmıştır. Üretim Akış tipi göz önüne alındığında Geleneksel Üretim Sistemlerinde, Sipariş Tipi Üretim Sistemi, Akış Tipi Üretim Sistemi, Proje Tipi Üretim Sistemi, Sürekli Üretim Sistemi, olarak 4 tip üretim sistemine rastlanmaktadır. Bu bölümde sistemlerin karakteristikleri incelenerek genel problemleri tanımlanmıştır. Hücresel imalat Sistemleri, JIT, MRP II, Esnek üretim sistemlerinin tanımlan yapılmış ve Grup teknolojisi ile geleneksel üretim sistemlerinin faydalı ve sakıncalı yönleri özetlenmiştir. İkinci bölümde; Üretim planlama ve kontrol sisteminin tanımı ve aşamaları, talep tahminleri, ana üretim planlaması, kapasite analizi, sıralama, çekme ve itme sistemleri ve bu sistemlerdeki kontrol fonksiyonunun işleyişi açıklanmıştır. Üçüncü bölümde; talaşlı imalatın söz konusu olduğu işletmelerde hücresel imalat yöntemlerinin kullanılması dünya çapındaki üreticilerin büyük çoğunluğunun ortak yönü olduğu, grup teknolojisinin tanımı ve grup teknolojisinin sağladığı avantajlar ve dezavantajlar açıklanmıştır. Ayrıca hücresel imalat sistemlerinin tasarımı için gerekli aşamalar açıklanmıştır. Dördüncü bölümde; hücresel imalat yöntemine geçebilmek için gerekli olan hücre tasarımlan için gruplama metotlar, elde edilen grupların tesiste yerleşimini sağlayan grup düzenleme tipleri ve oluşan grupların grup içi düzenleme analizi ve akış hattı oluşturma metotlar anlatılmıştır. Beşinci bölümde; uygulama yapılan fabrikanın tarihçesi, organizyonel yapısı hakkında genel bilgiler, fabrikanın genel görünümü ve genel yerleşim planı, ürettiği ürünün teknik özellikleri anlatılmıştır. Altıncı bölümde;(Bu bölüm grup teknolojisi uygulamasını içerir.) İşletmenin standart üretim zamanı içerisinde gösterilemeyen fakat mamulün işletme içerisinde kaldığı süre içerisinde akış süresi diye isimlendirilebilecek makinalararası taşırmalar, ayar ve hazırlık zamanlarım düşürecek olan grup teknolojisi uygulaması için adımlar belirtilmiş ve bu uygulama sonucunda elde edilen hücrelerin entegrasyonu yapılmıştır. Gruplama yöntemi olarak Mace kullanılmıştır. Yedinci bölümde; mamul parça ve model listelerinin oluşturduğu kodlama sistemi ve bu kodlama sistemine dayanarak oluşturulan hücresel imalat gruplarında yanmamul takip sistemi ve bu takip sisteminde kullanılan kartların içeriği açıklanmıştır. Amaç üretim hatlarında kalite spesifîkasyonlarına uygun malzemenin dalaşımını ve stoklanmasını düzenlemek ve takip etmektir. Bu bölümde ayrıca üretilen standart model motorlar için tip bazında, sahalardaki geçiş süreleri dikkate alınarak ve verilen kısıtlara göre kan maksimize edecek optimal imalat miktarım saptayacak bir lineer model kurulmuştur. Bu model Lmdo paket programında çözülmüş ve sonuçlan özetlenmiştir.

Recently, most of the companies's success is measured by the competitiveness in the international market. It has been a must to use the modern production techniques in companies to be a worldwide producer In the first chapter, production systems are defined and classified in two main groups;. Traditional Production Systems. Modern Production Systems Considering the production flow, traditional production systems can be divided into four groups;. Job Shop Production. Flow Shop Production. Project Type Production. Continuos Production In this chapter these production systems are examined and main problems of the systems are defined. Cell Manufacturing Systems and Group Tecnology, Flexible Manufacturing Systems, Just in Time Production Systems, Manufacturig Resource Planning and Computer Integreted Manufacturing Systems are explained as modern production systems. Group Tecnology (GT) is often use to identify families of parts that can be manufactured by similar operations. A manufacturing cell of workstations and machines can than be organized for these operations, resulting in a much simpler flow of part through the cell than with functionally-oriented lay outs The Group Tecnology prenciple may also be considered to organize planning and control for the team of workers who operate such a cell. Production supervision is often reorganized by GT product families rather than by functional process area. The cell team workers may have more variety in their work by operating many different types of equipments in the cell Generally, understanding What MRP II is ? does not mean the firm will implement it successfully because of this a direction should be laid out, activities should be identified clearly and spesific destination should be led. Manufacturing Resource plannig has proven to be an effective management weapon. xn manage all facets of production and inventory control and has now been extended to tie in accounting, purchasing, marketing, and distiribution. When operations are perfectly managed, customers are served exactly on time with no idle inventories between operations. A general name for this waste free ideal is Just in time. One of the JIT techniques, called kanban, has been formally recognized as an iventory timing technique. The general meaning of kanban is a communication or signal user to maker. The narrow meannig is card or visible more work. The signal can be anything that clearly communicates the need there are many formal kanban. The objectives of flexible manufacturing system is to incoorparate many individual automation concepts and technologies in to a sign production system. The system would include automatic storage and retrival systems, automatic material handling systems, robots, numerical control machine tools, group technology and hierarchical computer control systems. In a broad sense, Flexible Manufacturing Systems consist of three subsystems; fabrication, machining and assembly. Each of these subsystems may be highly integrated with automated storage and computer aided design systems. In this chapter, advantages and disadvantages of group tecnology and traditional production systems are summarized. In chapter two, production planning and control consist of the organization and planning of production activities. It arranges the benefits activities of meterials menpower and machines to obtain the desired production results using quality, quantity and place factors. This chapter describes the objectives of production plannig and control, forecasting demand, master production plan and scheduling, capacity analyses. Foreasting is the art and science of predicting future events. It may involve taking historical data and projecting it into the future with some sort of matematical model. It may be a subjective or intuitive prediction of the future. Forecasts are usally classified by the future time horizon that they describe. The three categories are short range forecast, medium-range forecast, long range forecast. Many scheduling techniques can be employed to schedule a job shop. The type of technigue used depends on the valume of orders, the nature of operations, and the overall job complexity. The selection of the technique also depends on the extent of control required over the job while is being processed. For example we would try to minimize or eliminate idle time in costly machine operations, and we might want xni to minimize the cost of work in process inventories at the same time. In practice, a combination of forward and bacward schedulung is often used. Forward scheduling assumes that procurement of meterial and operations start as soon as the requirements are known. In backward scheduling the last operation on the routing is scheduled first. The master schedule is the centerpiece of the plan for meeting customer demand for each item. Capacity planning has the purpose of keeping capacity utilization at the right levels and discussion of this importent spills. The net requirements and timing for any dependent demand item can be calculated by the material requirements planning method. The use of cell manufacturing techniques in chip type machining processes is the common point among the worldwied manufacturers In chapter three, some methods related ta grouping machines into cells and parts into families explained in the following. Another problem of group technology is to evaluate the dimensions of the cells with economic approach. The advantages of group technology are as follows;. A decrease in machine preparation period. Proper metarial flow. A decrease of inventories in process. A decrease of total process period. Simplicity in production plannig and control.. Improvement in quality and personal relations. However GT has some disadvantages and these are as follows;. The choice of the method which is the suitable for the forming of the machines groups and family parts is such a diffucult subject requiring detailed analysis.. Although minimizing the quantity of exceptional elements is a widely used methods, it's applications has not yet been proven. Different grouping criterias can cause different grouppings despite the same data and algorithms. In four chapter, this chapter describes the grouping methods used for the desing of cell manufacturing systems. The Mace Groupings Method which is commonly used in practice is explained with its algorithms. With different kind of grouping techniques, the step which comes after the division of products into families and the grouping the machines which are used to xiv produce these families is the position the groups of machines to the proper place in the plant. The services needed for each machine in the groups are considered during the process of positioning one group to another. The entegration of groups, and the placement inside the groups flow analysis are illustrated. In five chapter, this chapter gives the introduction about the factory which this project's practice exercised project goes on the describe company organizational structure, lay outs of plant, and the spesifications of the motors produced. Taşdelen facilities, which have 18.000 square meters of closed area, joined Türk Elektrik in 1989, and highly integrated production with 200.000 motor capacity per year. With design an manufacturing know how acquired from well known European motor manufacturers at its start up, the factory is producing high performance, three phase induction motors at the equivalent quality and apperance to many European brands. In six chapter, The objective of placement done by using of group technology is to improve such a system that provides simplicity and effectivenes in the computer aided production plannig and control. By using of group technology the factors increasing the cost of product and appearing in machine loading, sequencing and delivery timing decrease and the productivity increases. The transfer time which cannot be shown in standart time of production between the machines named as flow time decreases and the production planning and control becomes easier and more efficient. The production problems will be determined more easily and as the production flow succeeds personnel efficiency audit systems can be established. The basic steps are as follows; a) Analysing the factory placement and forming product flow diagrams. b) Determinig the motor parts families c) Machine grouping d) forming work in process inventories- following systems In the seventh chapter drawing coding system formed by product model and parts list and the cards formed by work in process inventory-product follow systems are explained xv As stated earlier the objective is to define the data base and types which provides the forming of computer aided work - in process inventory follow system in an effective production plannig and control system. To arrange the metarial flow in production two types of cards are prapered namely production ordering card and related production card. In addition to this chapter, a lineer model for optimal production quantity considering capacity restrictions and standart times is formed for standart motors. This model is resoved in the program, Lmdo, an results are defined.