Gradimir Danon

Prediction of the surface roughness of wood for machining

The surface quality of solid wood is very important for its effective response in manufacturing processes. The effects of feed rate, cutting depth and rake angle on surface roughness and power consumption were investigated and modeled. Neuro-fuzzy methodology was applied and shown that it could be useful, reliable and an effective tool for modeling the surface roughness of wood. Thus, the results of the present research can be successfully applied in the wood industry to reduce time, energy and high experimental costs.

Defining the functional and physical compatibility of a modernized tramway rolling stock with a newly planned LRT system: a case study of Belgrade

According to the Belgrade Master Plan for 2021, the public transportation system for the city and its region will include three rail modes: a modernized existing tramway, regional rail, and a new light rail transit (LRT) mode. In the coming years all three rail modes should be developed simultaneously and in a coordinated manner. The introduction of LRT is to be realized in several phases, and its first line will partially follow the alignment of an existing tramway line. As the present tramway vehicles are obsolete, new rolling stock must be designed and purchased to be compatible with many of the elements of the LRT. Ways to adjust the new tramways to the LRT rolling stock represent the central topic of this paper. The basic technical and operating characteristics of the new tramway are defined with respect to their required compatibility with the LRT stock and infrastructure.

Research of cutting power with cutting chipboards with different properties by circular saw

In this paper elaborates the process of measuring cutting power which occurred during cutting six types of particle board. Chipboards with different physical and mechanical properties were cut in order to find some correlation with the cutting power ie to be able to determine the effect of moisture, density and bending strength of the plate to the cutting power. Measuring power cut was made in the workshop of the Faculty of Forestry, Belgrade, measuring the moisture and density in the laboratory for testing particle board, and the bending strength was performed in the laboratory for testing the properties of wood. During the cutting speed are changed auxiliary movements to determine the influence of the machining parameters on cutting power. Overall, it was concluded that with increasing moisture content of the work-piece cutting power decreases with increasing velocity displacement, density and bending strength of the board, required cutting power increases.

Research of the effect of saw blade set dullness on the dimensions of longitudinally cut fir and spruce slats.

This paper analyzes the problem of choosing the best way of operating and maintaining a set of circular saws intended for longitudinal processing. The study objective was the analysis of current procedures of tools usage and recommendations for their improvement, in order to achieve better quality and longer operating life of tools. The tested set (24+5 blades) was mounted on multisaw blade machine which produces slats from fir or spruce planks for three-layer parquet. Changes in thickness of sawed slats, operation time between two sharpenings and blade size changes after removing saw blades from machine and aftesharpening, were monitored. Control x-charts were used for stability evaluation. Work quality of saw blade set for longitudinal cut of fir and spruce planks was presented by cost-effectiveness ratio, ratio of total costs (for purchase of set and its servicing) and volume of sawed timber. The saw blade set did not reach the targeted coefficient based on the previous tests. After each sharpening, the set had a different persistence presented in time, and we could not determine the work dynamics. The persistence of saw blade set was affected by wood resin that accumulates on the saw blade surface, the method and angles of sharpening, work dynamics and the continuity of cutting.

Influence of wood properties and technological parameters of processing on cutting power in milling of thermally modified beechwood

The paper presents results of influence of thermal modification on cutting power required for milling wood processing. The experiment was conducted for the different treatment temperatures (170°C, 190°C and 210°C) and different technological parameters of processing (feed and cutting depth). Cutting powers during milling were measured on four groups of beech wood samples, dimensions 35×16×400 mm, separately for heartwood and sapwood. The following mechanical and physical properties of the processed samples were tested: bending properties (modulus of rupture and modulus of elasticity), cross-sectional and tangential hardness, and air-dry density. The measuring device used for measuring, monitoring and displaying cutting power was developed at the Wood Machining Centre at the Faculty of Forestry in Belgrade. The results point out the differences in the powers required for processing heat-treated wood compared to untreated wood. The analysis shows that with the increase in treatment temperature, the required cutting powers decrease.