Increasing the life of mulching tools

Areas after mining or calamity are not amenable to immediate afforestation and require some adjustment. After removal of wood biomass, the rest of the residue is scattered throughout the area. To modify them, Several methods can be used to remove it. The optimal conditions for the planting environment and the subsequent adaptation process of the planting can be achieved by its mechanical, biological, chemical treatment. The basic prerequisite for a successful renewal of forests is their release from undesirable increases, in some cases from foams (trees) from mining waste. The area is also released when forest nurseries, seed plantations, etc. are established. The main purpose of the release of surfaces is to achieve the maximum throughput of the area for the machines to be moved. They wear during work. Wearing is a permanently undesirable change in the surface due to the interaction of functional surfaces or functional surface and wear medium. A tool that does not have any editing can go into a state where it can no longer be used anymore. An experiment was carried out in which 9 new teeth were placed on the rotor of the crusher and their wear patterns were observed. The article shows the progress of tool wear over time

Utjecaj promjenjivog koraka zubi kružnih pila na snagu za poprečno rezanje drva

The article deals with the influence of irregular tooth pitch on energy consumption of cross-cutting wood. In this article, the effect was assessed of feeding velocity and parameters of saw blade on the cutting power Pc of spruce (Picea Abies), pine (Pinus Sylvestris) and beech (Fagus Silvatica) wood during sawing with a guided circular saw. For the research, two types of circular saw blades were used, one of them having irregular tooth pitch. The circular saw blades had sintered carbide inserts with a diameter of D = 350 mm and the same number of teeth. The feed velocities were vf = 4, 8,12 m∙min-1 and revolutions n = 3000 min-1. The results showed that the circular saw blades with irregular tooth pitch have higher energy consumption than the circular saw blades with regular tooth pitch. The highest cutting power Pc was shown in the case of beech. It was also shown that energy consumption is increasing linearly with increasing feed velocity.U radu se prikazuje istraživanje utjecaja promjenjivog koraka zubi kružnih pila na potrošnju energije pri poprečnom rezanju drva. Analiziran je utjecaj posmične brzine, parametara lista pile i vrste drva na snagu rezanja (Pc). Eksperiment je proveden piljenjem drva smreke (Picea abies), bora (Pinus sylvestris) i bukve (Fagus silvatica) vođenom kružnom pilom. Za istraživanje su rabljena dva lista kružnih pila, od kojih je jedan imao promjenjivi korak zubi. Oba su lista kružnih pila imala oštrice od sinteriranih karbidnih umetaka, promjer lista D = 350 mm i jednak broj zubi. Primijenjene su tri posmične brzine: 4, 8 i 12 m∙min-1, a broj okretaja radnog vratila iznosio je n = 3000 min-1. Rezultati su pokazali da je potrošnja energije kružnih pila s promjenjivim korakom zubi veća od potrošnje energije kružnih pila s jednakim korakom zubi. Najveća snaga rezanja Pc zabilježena je pri piljenju bukve. Uočeno je da se potrošnja energije linearno povećava s povećanjem posmične brzine

Influence of the assembly method of sleeve joints on their strength

The aim of the study was to compare the strength of assembly joints of sleeve elements made of different structural, polymeric materials. Experimental tests were carried out to determine the mechanical properties of adhesive and welded joints. Adhesive joints were made of polyvinyl chloride pipes with the use of three types of adhesives: Epidian 53/PAC/100:80, Epidian 53/TFF/100:22, Vodaro 15010-VO. The welded joints were made of polypropylene pipes. All of the joints have been made with the use of a pipe fitting allowing for correct joints. Then the completed joints were subjected to destructive strength tests. The obtained results made it possible to carry out statistical analysis, which aimed at determining significant differences between the various methods of assembly. The tests carried out proved that the adhesive joints made with the Vodaro 15010-VO one-component adhesive were characterized by the highest strength - 2.30 MPa. The lowest strength was obtained in the case of adhesive joints made with Epidian 53/TFF/100:22 - 0.45 MPa epoxy ad-hesive composition. Statistical analysis showed that the strength obtained in case of adhesive joints made with epoxy compositions differs significantly from the strength of adhesive joints made with Vodaro adhe-sive. No significant differences at the assumed level of significance α=0.05 were also observed in the case of the strength of PP-R adhesive joints made with Vodaro adhesive and the strength of PVC-U welded joints

Innovation of the production process of coin dies to increase their service life

The article deals with the problem related to the service life of the coin dies. The faultless condition of tools during the long-time process of the production of the coins is a basement for their quality. It is influenced by several aspects. The most important factors can be considered the material of the coin die - especially its purity, relief production technology, heat treatment - especially the correct observance to procedures and the choice of equipment, achieved mechanical properties, method of final relief treatment - e.g., coating and the existence of residual stresses in the tool. The aim of the present research was to examine the cause of the failure and damage of the coin dies after production of a small number of coins and, accordingly, to make changes in the production process to prolong their service life. By monitoring the individual steps of the production process, it was possible to identify specific causes of premature decommissioning of coin dies. Innovations have been made at each step of the production process to extend the life of the coin. The paper presents the modifications in the heat treatment of the coin dies as one of the basic improvements in their no-failure long time operation. This, together with other identified shortcomings in the tool manufacturing process, has contributed to an increase in the number of coins minted from around 6,000 to 740,000 coins. © 2023 The Authors. Published by Elsevier B.V.Ministerstvo školstva, vedy, výskumu a športu Slovenskej republiky, (APVV-19-0550); Kultúrna a Edukacná Grantová Agentúra MŠVVaŠ SR, KEGA, (005TUKE-4/2021

Evaluation of some parameters of hard surfacing treatment of the functional surfaces of forestry tools

In this paper we discuss the possibility of increasing service life of tools used in forestry for mulching of undesirable forest growths. In a heterogeneous working environment in which they are operated, such tools are subjected to constant abrasion and impact loading. There are several ways how to extend their service life and operational fitness. One of these is hard surface treatment, or hard surfacing of their functional surfaces. In our experiment, we chose suitable hard surfacing materials and applied these on the sample materials using the MMA and MAG welding. The hard surface was applied in an one layer. Subsequently, we performed hardness tests, microscopic analysis of the structure of the basic material and the hard surface and evaluation of the fusion penetration of the base material with the hard surfacing weld. Fusion is crucial as it determines the cohesiveness of the weld and base materials and thus also the actual extension of the service life of the tools

Relation between theory and practice in contemporary higher education

The paper summarizes the discussion at the panel session „Relation between theory and practice in contemporary higher education” at the Business Trends conference organized by the Faculty of Economics of the University of West Bohemia in Plzeň, 2014. Afte r brief introduction emphasizing the importance of universities and businesses leading to better preparation of students to their professional careers, Section 1 introduces to the methodology of panel discussion as a research tool and brings references to some examples of panel discussions and their recordings. Section 2 summarizes discussion that took place at the conference panel. It focused on the discrepancies between requirements of companies and competencies of universities graduates, identification o f some barriers of cooperation between those two players and recommendations how to improve it. Section 3 presents t wo case studies describing practices and approaches used to overcome the barriers described in preceding text at two universities – Univers ity of West Bohemia in Plteň and Faculty of environmental and manufacturing technology in Zvolen

Vztah teorie a praxe v současném vysokém školství

The paper summarizes the discussion at the panel session „Relation between theory and practice in contemporary higher education” at the Business Trends conference organized by the Faculty of Economics of the University of West Bohemia in Plzeň, 2014. After brief introduction emphasizing the importance of universities and businesses leading to better preparation of students to their professional careers, Section 1 introduces to the methodology of panel discussion as a research tool and brings references to some examples of panel discussions and their recordings. Section 2 summarizes discussion that took place at the conference panel. It focused on the discrepancies between requirements of companies and competencies of universities graduates, identification of some barriers of cooperation between those two players and recommendations how to improve it. Section 3 presents two case studies describing practices and approaches used to overcome the barriers described in preceding text at two universities – University of West Bohemia in Plteň and Faculty of environmental and manufacturing technology in Zvolen