Similarity Based Project Planning in the Field of the Production of Individual Machines T. Tóth 1,2 , F. Erdélyi 2 , S. Radeleczki 3 1 Department of Information Engineering, University of Miskolc 2 Production Information Engineering Research Team (PIERT) of the Hungarian Academy of Sciences; University of Miskolc 3 Institute of Mathematics, University of Miskolc Abstract Production planning and scheduling is one of the most important technical activities of enterprises in the manufacturing and engineering industries. Project-like production planning is a typical engineering function of manufacturers that make very complex products according to special customer orders. Manufacturing companies that produce individual (one-of-a-kind) type machines (e.g. machine tools, production devices, customer demanded equipment, special vehicles, etc.) frequently encounter the problem that many uncertainties are present at the stage of the business offer. Product specifications exactly meeting the requirements of the customer are not fully available therefore inserting the project into the running tasks requires careful aggregate planning. In creating the project models the similarity of projects can be advantageously utilized. This paper gives an overview of the theoretical background and summarizes the expected benefits of the proposed approach. Some initial application experience obtained at a Hungarian factory will also be outlined. Keywords: Production planning, aggregate planning, project, similarity, intensity/rate profile 1 INTRODUCTION Production planning and scheduling (PPS) is one of the most important engineering and management activities in the manufacturing and engineering industries. PPS establishes contact between the results of product design and process planning, as well as real production and logistic processes. Production Planning (PP) is generally carried out at several hierarchy levels and on a few different time horizons. Middle-term and long-term production planning is frequently named aggregate planning. Enterprises producing individual machines frequently face the problem that the technical activities required to make a product are only known with a significant uncertainty in the phase of tender. In the course of aggregate planning of the project view the most critical decision is related to the performable delivery date of a machine that meets all the customer’s requirements. A detailed account on project-like aggregate production planning is in a recent paper [8]. The authors of the present paper have collaborated with the authors of the cited article within the framework of a research consortium. To make a reliable estimate of the time needed, the activity demand of the project under discussion has to be fit into the current production plan. Aggregate production planning can also be defined as distribution of abstract production activities in time, taking into consideration the constraints both in sequence and time, under limited resource capacities, making an effort to meet an optimum criterion. Numerous summarizing books deal with the most important features of aggregate planning. For instance, an excellent survey can be found in the handbook [6]. Aggregate production planning includes two tasks that can be separated from each other. The first task is to support the decisions concerning the time of delivery in the tender-phase of the project. (The decisions regarding supply-chain and co-operation are also included). The second task, in the case of the projects confirmed by contract, is to plan the operations of production both in volume and time in a correct way, on the basis of the product design and technology process plans, as well as using the data of the external order. In the project model of the production of individual machines the number of abstract activities and their types are equally influenced by the number of projects, the time horizon, the time unit of planning, the work demand of the projects and the constraints in sequence. Let us consider a medium-size enterprise working in the field of manufacturing and engineering, which realizes 20-30 projects in parallel. At this enterprise characteristic aggregate and abstract activities can be as follows: (1) mechanical engineering design and process planning; (2) electrical design; (3) part manufacturing; (4) mechanical assembly; (5) electrical assembly (wiring, mounting) and testing. In Figure 1. we demonstrate the typical connections of the project activities of individual machine production in time. Up-to-date market demands require the execution of these activities in a sequential-parallel (combined) way. Concurrent Engineering, a modern branch of knowledge summarizes the conditions and methods of this combination.