Optimizing Time Utilization of FMS

The aim of the research is to solve the problem of simultaneous production on the flexible manufacturing system with different combination of product types and quantities that will give maximal utilization of production system. The presumption for good utilization of FMS (Flexible Manufacturing System) is in forming of working order with such product type structure that will make possible of production processing with minimal time load of complete production system. Working order structure from the point of product types and quantities is dictated by market demands that are known earlier. Because the structure of particular working order is not harmonized with the exploitation characteristics of FMS, we are faced with problem how to realize working order in such conditions as well as how to achieve main goal: shorter machining cycle with less time occupation of production system. The method based on two phases for solving problem of control working order realization is presented in the work. In the first phase the selection of optimal combination of process plans which gives minimal time load of production system through simultaneous production of different products and their quantities is given. In the second phase the order of part production and the order of particular operations processing is optimized. The optimization problem in both phases of control is solved by application of genetic algorithm approach. The software for computing and optimizing of processing order on FMS is developed

Determining the Minimum Waiting Times in a Hybrid Flow Shop Using Simulation-Optimization Approach

Planning the order and size of batches is an extremely complex task especially if these tasks are related to production companies in a real environment. This research deals with the problem of determining the entry order and size of product batches in order to optimize inter-operational waits, in the form of waiting in queues for processing and waiting due to the setting-up of the workplace. In real environment, these waits represent a large share of the time spent in the production of a unit of product in a hybrid flow shop. This problem is almost impossible to be solved with analytical models because they may require many simplifying assumptions. Therefore, a simulation-optimization approach is used to solve this problem. Discrete event simulation allows greater flexibility in the representation of the real production system, while the integrated optimization tool, a genetic algorithm, serves to find the optimal solution relatively quickly. To ensure simpler production management, batch size is defined as a fixed value with the exception of a different first or last batch which represents the difference to the required production volume. Therefore, two optimization cases are presented in the paper. Although both cases show improvements, the case when a different batch is the first batch shows better results. In that case, the share of setup time in the total production time of the product unit was reduced from 4% to 3%, and the share of waiting time in the queue for processing was reduced from 76% to 32%

Contribution to faster artifact classification by creating an expert database

This paper proposes a method for faster classification of artifacts that appear during radiological recordings. Section images containing artifacts require significant additional post-processing time compared to other, artifact-free sections. The areas containing artifacts were identified and gradually analyzed in order to optimize the fabrication process. Guidelines for creation of an expert database are given. A suggestion is presented for defining a new expert knowledge database filling method

An Economic and Visual System for Position Check

Fast and efficient position check is extremely important in the production cycle. It is hard for us to check every particular detail in series because of the short time period. So far, the mode of operation has been associated with statistical laws. Depending on the size of series, a random sample is taken in certain percentage, and afterwards the position and geometry are manually controlled. This paper attempts to analyze photogrammetrical approach which allows simple automatically controlled positions set in advance as well as undemanding documentation of all analyzed parts. This kind of approach came into being in a vast industrial environment with a great tendency for further development. For the purpose of the research, the program solution has been developed. This kind of approach recognizes the type and sort of parts automatically and then loads relevant control positions from the database. The proposed approach reduces time needed for position control and therefore enables greater control of higher amount of parts which in turn directly contributes to earlier failure detection. On the other side, program solution can easily be adapted to specific situations in the production plant. As a result of the increase of automatization level, the need for employment is lower and as a result also the cost of control

Uporaba tehnološke dokumentacije kod izrade fiksacijskih pločica za vestibuloplastiku

Aim: The implementation of computer applications has become a necessary step in providing higher quality service to patients receiving dental/medical prosthodontic restorations. Thus, the aim of this research was to determine the time necessary for the vestibuloplasty fixation plate manufacturing using the computer aided method based on the computer- aided design and computer-aided manufacturing (CAD/CAM) technologies, and then compare it with the conventional method, which is presently used in common practice. Methods: During this research two vestibuloplasty fixation plates were manufactured. The first one was made as per conventional method using the alginate impression and hard stone, while the other one was made using new computer aided method based on the CAD/CAM technologies. Using both methods, we analysed the total time for fixation plate manufacturing as well as necessary steps in process. In addition, access, documentation creation and transport between dental laboratory and the dental/medical office time were also analyzed. Results: The use of the CAD/CAM technologies ensures the continuity of all steps in the process of vestibuloplasty fixation plate production. Electronic documentation created in this way can be stored at a network server and become available for wider range of users. Data analysis indicates that the number of steps used in the computer based method is decreased for 18,1 % compared with the conventional method. Improvements indicate that documentation preparation time was decreased for 30,0 %, and time for documentation access was reduced for 86,7 %. Time for documentation creation was decreased for 40,0 %. This computer method also increased transport time efficiency for 83,3 %. In comparison with the conventional method, the total time necessary for fixation plate manufacure was significantly reduced for 51,6 %. Discussion: The use of computer aided method based on the CAD/CAM technologies in comparison with the conventional method significantly accelerates production time in dental/medical office thus raising the level of service.Cilj: U svrhu pružanja kvalitetnije usluge bolesnicima dentalno-medicinske protetike, implementacija računalnih rješenja postala je nužan korak. Stoga je cilj ovog rada utvrditi potrebno vrijeme za izradu fiksacijske pločice za vestibuloplastiku računalnim rješenjima baziranim na CAD/CAM (engl. computer-aided design and computer-aided manufacturing) tehnologiji i usporediti ga s izradom fiksacijske pločice konvencionalnom metodom, uobičajenom u praksi. Metoda: Tijekom ovog istraživanja izrađene su dvije fiksacijske pločice. Jedna pločica izrađena je konvencionalnom metodom pomoću alginatnog otiska i sadrenog modela, a druga uporabom novih računalnih rješenja i CAD/CAM tehnologijom. Korištenjem obje metode analizirano je ukupno vrijeme potrebno za izradu fiksacijske pločice, kao i broj potrebnih koraka za izradu istih. Također je analizirano vrijeme potrebno za izradu i pristup dokumentaciji, te vrijeme transporta između zubotehničkog laboratorija i ordinacije dentalno-medicinske protetike. Rezultati: Uporabom CAD/CAM tehnologije osigurala se slijednost svih koraka u postupku izrade fiksacijske pločice, a računalna dokumentacija mogla se pohraniti na serveru i učiniti dostupnom širem krugu korisnika. Analizom podataka vidjelo se da je broj koraka primjenom računalne metode u odnosu na konvencionalnu manji za 18,1 %. Vrijeme potrebno za pripremu dokumentacije kraće je za 30,0 %, za pristup dokumentaciji 86,7 %, dok je vrijeme za izradu dokumentacije manje za 40,0 %. Primjenom računalne metode vrijeme transporta skraćeno je za 83,3 %. Ukupno vrijeme izrade fiksacijske pločice računalnom metodom u odnosu na konvencionalnu metodu smanjeno je za 51,6 %. Rasprava: Uporaba računalne tehnologije u odnosu na konvencionalnu metodu značajno ubrzava vrijeme rada u dentalno-medicinskoj protetici, te na taj način podiže razinu usluge

Production Planning and Optimization of Work Launch Orders Using Genetic Algorithm

This paper presents genetic algorithm approach for simultaneous production planning and optimization of work launch orders. Genetic algorithm was used to optimize overall quantities of each machine, work launch orders and the number and size of lots, which are going to be launched into production in each operative period. Simulation of work launch orders and quantities of each machine was performed using linked lists of empty spaces. Optimal machine quantities were achieved using linked lists of empty spaces combined with the gene editing procedure. This study has shown that the proposed genetic algorithm can find a shorter production cycle of production assortment inside the operative period, using smaller machine quantities

MANAGEMENT OF ELECTRONIC DOCUMENTS IN QUALITY MANAGEMENT SYSTEM ON TF RIJEKA

Upravljanje dokumentima u elektronskom obliku s definiranim procedurama omogućuje brzo i efikasno upravljanje dokumentima u sustavu upravljanja kvalitetom prema normi ISO 9001:2008. SharePoint portal na Tehničkom fakultetu Rijeka omogućuje korisnicima uključenima u sustav upravljanja kvalitetom lakši i brži dolazak do traženih dokumenata. Informacija, dokumentacija, specifikacija, plan kvalitete, poslovnik kvalitete i zapis predstavljaju dokumente koji omogućuju komunikaciju i kvalitetno upravljanje organizacijama. U ovome radu predstavljeno je upravljanje dokumentima u elektronskom obliku u sustavu upravljanja kvalitetom na Tehničkom fakultetu Rijeka.Managing documents in electronic form, with defined procedures, enables fast and efficient document management in a quality management system established according to ISO 9001:2008. The SharePoint portal at the Faculty of Engineering Rijeka allows users involved in the quality management system easier and faster access to requested documents. Information, documentation, specifications, quality plans, as well as quality rules and records represent documents that enable communication and quality management in organizations. In this paper we present the electronic form of the management of documents of the quality management system at the Technical University of Rijeka

Conceptual framework for creating customized modular CAPP system

Information and communication technologies have a central role in the manufacturing system integration process. In this paper, a conceptual framework for the integration of available software applications is presented. Analysis of Croatian industrial enterprises is used to create a feasible computer aided process planning model. The suggested model uses the built-in ability of installed software for sharing information derived from processes with which they are connected. Information is then used for generating the optimal process plan for the current surroundings in the central CAPP module. Using the presented conceptual framework, modular CAPP solutions are created and customized to fit the needs of different manufacturing enterprises, taking into consideration the implementation costs and time