ABSTRACT Almost for all methods of optimization, simulation, revitalization and control of processes, it is necessary to define the mathematical model of a process. In the examined case, the process parameters have been identified and the mathematical model of the impakt wave pressure has been defined in case of pulling out by explosion. The model correctly describes, within the examined range and with certain degree of accuracy, the process of the impact wave provoked by explosion in water being the media for power transmission.In this case, a 200-mm bottom made of Steel 4580 was being shaped. Speed of detonation was 2994 m/s and 6105 m/s. Explosive used in this case was Vitezit 20.

In the observed case there will be presented a process of determining dynamic coefficient both based on existing theoretic equations for determination of required pressure, and based on experimental results of testing. As a matter of fact, a dynamic coefficient is ratio between dynamic and static pressures and will be deduced from conditions of the equal deformation degree on the occasion of explosive-induced deep drawing of sphere-bottomed sheet. In the observed case a sphere-bottomed sheet, with 200 mm diameter and steel _4580 (DIN X5CrNi 189), was deep drawing by means of explosion. Explosive’ s detonation velocities were 2994 m/s and 6105 m/s. The used explosive was “ Vitezit 20” , while medium for energy transmission was water.

U Bosni i Hercegovini zbog pravne nesigurnost, usitnjenog ekonomskog prostora, jakog sivog tržiste i korupcije, birokratskih barijera privatizacija nije okoncana. Svi ovi nedostatci dovode do smanjenog ulaganja u Bosni i Hercegovini odnosno slabi interes za privatizaciju. Visegodisnji zastoj u industriji prerade metala u Bosni i Hercegovini uzrokovao je i zastoj u razvoju postojecih i implementaciji novih i suvremenih tehnologija. Razina primijenjenih tehnologija u vecem dijelu proizvodnih procesa i prije rata je bilo neminovno revitalizirati i dovesti u tehnolosko stanje koje ce garantirati produktivnu proizvodnju. Visegodisnji zastoj je tehnolosko stanje proizvodnih procesa i sistema samo pogorsao, tako da u vecini metalne industrije treba izvesti temeljite tehnoloske zahvate u selekciji tehnologija na one koje se ne mogu revitalizirati i na one koje se mogu revitalizirati do tržisno upotrebne vrijednosti, te na one koje imaju zadovoljavajuci tehnolosku razinu pa ih nije potrebito revitalizirati.

Today, in world exist completely new trends in build up the machine tools and the machining systems. Numerous demands of the market for increasing precision of the machined surfaces and products assortment as well as short delivery times with lower product prices require the development of adequate machining systems which can to respond advanced production techniques. The review of some characteristics of existing machines and some trends in the development of machine tools with special regard of parallel kinematic structures is given here.

The objective of the entrepreneurial sector regeneration can be, and is, production for export. To export onto the internal European Union market, product's compatibility with the appropriate EU regulations on product safety must be proven. Products made according to the EU regulations are the driving engine of European integrations. Federation B&H ecconomy is comprised mainly of small and medium enterprises (SME). Succesful SMEs from clusters by networking, and accomplish the following objectives: creation of added value, improving their competitiveness and innovative power. Clusters and a path to transforming a small economy into a ''large'' one. Only successful and powerful economic subjects can find partners in the European regional system, and assure sustainable development.

Using explosive as a source of energy in the process of shaping tin-sheet is possible in volume shaping process as well as in other processes of tin-sheet shaping, e.g. making holes, calibration, surface hardening, etc. In this case, a 200-mm bottom made of C 4580 was being shaped, and the structure of material was examined as well. Speed of detonation was 2994 m/s and 6105 m/s. Explosive used in this case was Vitezit 20, and the medium for transmission of energy was water. Mentioned steel, before it was being shaped, had austenite structure and it belongs to non-magnetic steels, it cannot be tempered, it is hard to be shaped by cutting, but it is good to be drawn.

Prilikom upravljanja i modeliranja sustava uglavnom se polazi od opce analitickih modela koji se mogu definirati. Najcesce zbog kompleksnosti sustava u strojarstvu, kao i pojedini tehnoloski procesi veoma su složeni tako da se opci model rijetko kada može uspostaviti. U takvim slucajevima umjetne neuronske mreže mogu se uspjesno primjeniti. Njihova primjena može se koristiti u razlicitim oblastima proizvodnog strojarstva pri cemu su se izdvojile klasifikacijske kategorije, predikcija i funkcionalna aproksimacija.

Mathematical modelling has more and more meaning in the technological processes with the aim to establish the quantitative and optimal relationship between input variables Xi and output effects of machining process Y=Y(Xi). A review of applicable mathematical methods of modelling is given in the machining processes: stochastical, numerical, analytical and dimensional method.

The given experimental and modelling method are shown that the tribological state on the contact surface of tool and workpiece can excatly be determined by means of contact stresses, contact coefficient friction and contact temperature on tool. The developed mathematical models described on adequate reliable method the tribological state in cold forming process. In this paper are presented tribological models for the backward and forward extrusion, deep drawing, rolling, profiles drawing and the method by sensors pins in tool for contact stress measurement on contact surface of tool.

Constant compressive stress creep exp∼riments in jhe temperature and stress ranges of 1420K – 1570K and 50 MN/m 2 –350 MN/m 2 have been conducted on hot pressed unreinforced Si 3 N 4 containing the densification aids of 6 wt% Y 2 O 3 and 1.5 wt% Al 2 O 3 and on a similarly prepared composite material reinforced with 20 vol% SiC whiskers. Steady-state creep data obtained on these materials in a N 2 atmosphere gave stress exponent values of 1.2 – 1.6 and 0.4 – 1.6 for the unreinforced Si 3 N 4 and the composite, respectively. A break in the steady-state creep rate vs. log stress observed only in the composite occurred at approximately 250 MN/m 2 at the temperatures of 1520K and 1570K. This information coupled with the results of electron microscopy indicate that the temperature as well as the extensive crystallization (or lack of it) of the amorphous grain boundary phase are the principal factors controlling the deformation rate at a given stress within the limits of the small total strains achieved in this research.