Üretim kaynakları planlaması (MRP II) ve yan sanayi maliyet analizi ve kontrolü sistemi

Abstract

Bu çalışmada bir işletme için çok önemli olan planlama faaliyetlerinin günümüz iş dünyasında ulaştığı son aşama olan MRP II sistemlerinin gelişimi ve çalışması üzerinde durulmuştur. Birinci bölümde üretim planlama ve kontrolünün amaçlan ve fonksiyonları incelenmiştir. Üretim planlamanın üretim tiplerine, işlerin akış şekline, kapsadığı döneme göre farklı sınıflandırılmaları yapılmıştır. İkinci bölümde Üretim Kaynaklan Planlamasının en önemli bölümlerinden üçü; Malzeme İhtiyaç Planlaması, Ana Üretim Planlaması, Kapasite İhtiyaç Planlaması modülleri ve birbirleriyle olan ilişkileri incelenmiştir. Her bir modülün çalışma prensipleri, veri tabanı yapılan ve iş akışları incelenmiştir. Üçüncü bölümde Üretim Kaynaklan Planlaması, alt modülleri ile birlikte incelenmiştir. MRP IFnin bir işletmede uygulanmasının yararlan belirtilmiş ve bir uygulama prosedürü tanıtılmıştır. Bölüm sonunda, MRP Il'nin Tam Zamanında Üretim Felsefesi ile karşılaştırılması yapılmıştır. Dördüncü bölümde Satın alma Kontrol Sistemi ve MRP II içindeki yeri incelenmiştir. Satın alma fonksiyonları ve politikaları, Tam Zamanında Satın alma ve Maliyet Analizi kavranılan incelenmiştir. Beşinci bölümde ise Türkiye Elektrik Endüstrisi Sistem İşletmesi'nde Üretim Planlama ve Stok Kontrol ile Malzeme Satınalma sisteminin incelenmesi yapılmıştır. Bu sistem kapsamında yan sanayi firmaları ile fiyat görüşmelerine baz oluşturabilecek bir 'Yan Sanayi Maliyet Analizi Sistemi' geliştirilmiştir. Bu sistemin akış diyagramları ve veri tabanı tasarlanmıştır. Bu sistemin, şu anda işletmenin yüksek cirolarda alım yaptığı yan sanayi firmalarının maliyet analizlerinde kullanılması için çalışmalar yapılmaktadır.

Production concept was first seen in the history when human beings could no longer get all his requirements from the nature. Human beings began to produce and developed the production techniques. Afterwards, in order to produce more he built workshops and factories. As the production gets more complex and confusing, it was seen that all the phases of production could not se managed by only one worker and division of labor became compulsory. At this point, to be able to manage the whole production cycle, one should plan and organise the ways and sources of his workshop or factory. Production is a group of actions at the aim of creating a substantial thing or a service, in the economical point of view. Production is changing a substantial thing with increasing its value or converting raw materials or sub-products into products, in the engineering point of view. The development of technology affected the firms as well as the other fields. With the help of technological development, new technics were developed instead of the traditional ones. The use of machinery even robotics spred all over the world. Production process is carried out in connected but separate units. Any change or problem in any of the workshops affect the others. At this point it is required to plan the interaction between the workshops in the most efficient way. The firms have to plan and manage their sources efficiently and effectively in order to survive in a competitive market. As the firms get bigger and the actions get more confusing the accurate and on time flow of information become impossible because of the volume of the information. The exchange of information between the departments of the firm which interact with each other becomes harder. This situation forces the firms to connect production, finance, marketing, accounting and purchasing functions with the help of computers. Manufacturing Resources Planning ( MRP II ) is the most extensive approach in this field. Computer programs were first introduced in the field of accounting where data work is routine and a lot. Afterwards the concept of controlling the more complex production processes was introduced. This concept is known as MRP (Material Requirements Planning). Since MRP did not care about the capacities there occurred a lot of problems. MRP IE which also take the capacity into account is the next step of MRP. In this study, " Manufacturing Resources Planning ( MRP II ) and Material System " the main aim is to analyse the development and the mechanism of MRP II system. In the first chapter, the purposes and functions of production planning are analysed. Production planning and control actions are classified according to different criterions such as production types, the flow types and time horizon types. In the second chapter, three important modules of MRP II system; Material Requirements Planning, Master Production Scheduling and Capacity Requirements Planning modules and their interaction with each other are analysed. Material Requirements Planning ( MRP ) is an advanced technique that analyses current and future manufacturing plans to project an optimum materials plan. Using the ordering policies, lead times and product structure information established in the Bill of Material System ( BMS ), the inventories and orders maintained in the Material Control System ( MCS ), and the schedules coming from Master Production Planning ( MPS ), MRP creates the time phased projection of the firm's component part requirements in relation to available inventory. MRP determines when manufacturing, purchase and vendor subcontract orders should be placed, adjusted, rescheduled, or cancelled and makes the necessary recommendations to ensure that the firm have the right materials on hand when it needs them. Description and purposes of Material Requirements Planning are analysed in this chapter. The pro-conditions and assumptions are stated. Inputs of MRP systems are Bill of Material and Inventory Data. Outputs of MRP systems are the releasing of planned purchase orders and production scheduling orders. In order to implement MRP there are some priorities and technological approaches which should be considered seriously. MRP should concentrate on purchased parts, produced parts and products. Priorities such as planning priorities and precedence priorities should be considered. A major challenge that manufacturers face is converting the company's overall sales and profit goals into an comprehensive production schedule that is not only attainable, but makes effective use of available resources. Master Production Scheduling ( MPS ) helps to make the right strategic production planning decisions and enables master scheduler to effectively control and manage the resulting master production schedule. MPS enables users to model products and production plans for standard make-to-stock products, as well as those manufactured to customer specifications. The master scheduled item can be saleable end products, subassemblies, fabricated parts, or purchased materials, depending on the needs of the company. The types of master scheduled parts, planning of bill of material according to product choices, flexible date and detailed planning, various consumption prediction techniques, flexible capacity and load profile, and balancing load to capacity subjects are analysed in this chapter. One of the most challenging problem that manufacturers face is determining future requirements for labor and machine capacity. User can probably predict with some certainty the revenues he expects to generate, but he must have the available capacity to support his revenue plans. MRP II system manages firm's production plan through Master Production Scheduling ( MPS ), and generates a detailed material plan through Material Requirements Planning ( MRP ) and the Material Control System ( MCS ). The open orders in MCS and planned orders from MRP, in turn, drive Shop Floor Control ( SFC ) and Capacity Requirements Planning ( CRP ), providing the necessary released, firmed, and planned capacity requirements for both labor and machines. XI CRP uses both current and planned manufacturing activities to project the consumption of work center capacity. In addition to the scheduled work load from Shop Floor Control, CRP uses planned orders from MRP along with work center and standard routing information from Process and Routing System ( PRS ) to build a complete picture of capacity needs. In this way, CRP alerts to capacity problems before they have a negative impact. Capacity management levels, required data for capacity requirements planning, the capacity requirements planning process, the outputs of capacity requirements planning, the causes for capacity problems and managing the capacity changes through planning horizon are analysed in this chapter. In the third chapter Manufacturing Resources Planning ( MRP II ) system is analysed. MRP II concept is defined and its modules and database are extensively analysed. The ways and advantages of implementing MRP II systems are stated. Some techniques for selecting and implementing MRP II systems are stated. A procedure model for MRP II systems is given. At the end of the chapter the comparison of MRP II systems and Just in Time manufacturing is given. MRP II is a set of techniques used to plan all the resources of production firms. MRP U aims to combine activities like production, marketing, purchasing, production planning, inventory control, accounting within a system. MRP JJ is a new approach to the activities of the firm. In order to get successful results, a formal system should have been formed. The advantages that MRP II systems form can be summarised as follows: * Development in the customer service. * Decrease in inventory stocks. * Accurate and fast decisions. * Improvement in cash flow and financial plans. * Decrease in purchasing costs. * Increase in labor and resources usage. * Development of communication between job functions. * Increase in motivation and job-satisfaction of the workers. * Described duties and responsibilities. In order to implement a MRP II system in a firm wholly the main steps stated below should be maintained: * Requirements analysis and conceptual design. * Detailed design and realisation. * Preparations for productive system. * Production start. Analysing through MRP II system and production another similar concept, Just in Time Manufacturing, can not be looked over. The differences between MRP II and JIT concepts are discussed at the end of the third chapter. The main subject of the fourth chapter is Purchasing Control System. Purchasing functions and policies, just in time purchasing systems, vendor selection and evaluating, and cost development system is analysed in this chapter. For many manufacturers, purchased materials make up a major portion of the final cost of a product. The Purchasing Control System ( PCS ) helps manufacturers reduce this cost in all phases of the purchasing cycle. PCS manages the entire range of purchasing functions, from initial vendor sourcing through XII receiving and inspection. PCS operates in conjunction with the Material Control System ( MCS ), under the direction of Material Requirements Planning ( MRP ) to execute the purchasing portion of the materials plan. The Accounts Payable System helps completing the purchasing cycle. PCS has the flexibility to meet the needs of many manufacturing environments. It enables the user to purchase inventoried as well as non-inventoried goods and services and helps the user implement Just-in Time material replenishment. Flexible policy controls and free-form text capabilities helps user define his unique purchasing environment and enhance both his internal and external purchasing communication. On line, real time processing and extensive on line editing make the system easy to use and help ensure that purchasing information is current and accurate. PCS monitors purchasing performance, providing buyers with critical quality, delivery and price performance information. The purchasing cycle includes the following steps: * MRP Demand. * Quotations, Vendor Sourcing. * Purchase Decision Support. * Issue Purchase Order. * Follow up Expedite. * Receive Goods. * Inspect Goods. * Audit Invoice. * Pay Invoice. * Monitor Invoice. Reduced clerical effort, accurate and timely information, and improved communications shorten the purchasing cycle and enable buyers to focus more productive effort on value analysis and informed decision making. These activities pay off in reduced procurement costs, better quality materials, more on-time deliveries, shorter lead times, and reduced inventory investments. The data base of purchasing system mainly includes the following data: * Material Master Records. * Vendor Master Records. * Quoting Records. A common problem shared by many buyers is a lack of good information on which to base sourcing decisions. Even when information is available, it is often outdated and does not accurately reflect the current market. PCS is designed to make sure buyers have the current information they need to make the cost-effective sourcing decisions. These comprehensive capabilities provide current information on vendor performance, item performance, and item/vendor performance. Price quotations obtained from vendors can provide valuable information for purchase decisions and help reduce placed-order follow-up. But far too often quote information is not up-to-date and time does not permit user to obtain new quotes from vendors. To prevent these problems, PCS automatically reviews item with activity and items which have planned requisitions within the quote lead time to determine if sufficient non-expiring exist to cover them. With the help of MRP II system purchasing of right material at the right quantity and time is possible. Just in Time Purchasing Systems also try for the same purpose. The basics of Just in Time purchasing can be classified as follows : XIII * Just in time, in little batches, %100 qualified material receiving. * Unique vendor as material basis. * Long term purchasing contracts. * Operational and Cost transparency. * Interaction based upon cooperation. Another important point is vendor selection and evaluation. The criterions for vendor selection and evaluation can be classified as follows: * Material quality. * Long range cooperation. * Transportation performance. * Geographical location of the vendor. * Price. Regardless of the industry or the manufacturing processes used, all companies must price products and control costs. Successful pricing and cost control strategies require accurate product cost information. A product's cost includes not only the direct material and labor consumed, but also that product's share of every other expense of doing business. These indirect costs are typically assigned to the product through various overhead allocation methods. The constant change in today's globally competitive manufacturing business environment adds new complexity to product costing. As a result, manufacturing management requires flexible information systems designed for effective product cost analysis and simulation. The cost Development System (CDS) not only ensures that product costs are accurately developed and clearly reflect the expense of doing business; it helps to simulate projections of what those costs will be in the future. The Bill of Material System ( BMS ) and Process and Routing System ( PRS ) combine to provide foundation for CDS. BMS provides CDS with key item information such as shrinkage percent, and product structure information such as the quantity and scrap allowance for each component material. PRS supplies CDS with standard process routing information such as run hours, set up hours, yield rates, labor grades, work center identifications, work center efficiency factors, and outside vendor costs. CDS maintains the remaining purchased material costs, labor rates and overhead rates necessary to accurately develop each product's cost. This information, along with the bills and routing, is used to calculate material, labor, and overhead costs for each product on level-by-level basis. In the fifth chapter an application is introduced. The production planning and purchasing flow in " Türk Elektrik Endüstrisi Anonim Şirketi ". The aim of the study is to follow up the production planing and purchasing flow and find solutions to existing problems with vendor firms such as expediting and pricing. Factors like changing market conditions, rivalry, costs, proficiency, the volume of the production volume and etc. force enterprises to buy or order the raw- materials or semi-finished products from the other firms. Even this process is supported by the enterprises since it simplifies the production process. At this point the enterprise wants to have more information about the production phase of the received product. Adding to cost control of the vendor firm, improvement of the XIV processes and technical support are also planned and carried out. In Cost Analysis and Control process such an approach is applied.