Lubomir Javorek

• Associate Professor; MSc.(Eng.); PhD.
• Technical University of Zvolen

The quality of the surface of wooden elements that have been turned and burnished has got a crucial meaning in the whole production process flow, since the obtained effects affect the quality of the wooden surface after finishing (coating, painting). In the paper, selected results of the investigation of the effect of the burnishing process on the...

We carried out the measurement of the three components of the cutting force as a function of the modification of the depth of cut during the longitudinal turning process. The results show that if we increase the depth of cut, all three components of the cutting force shows increasing tendency, regardless of how much the cutting speed and feed speed...

In this contribution is analysed the force component of final force (passive force) by peripheral milling operation. Therefore, the main parameters that had influence to independent variable were revolutions, back engagement of a cutting edge ae, working engagement of the cutting edge ap. The article deals with the issue of milling in material AlMg...

The paper presents the experimental results of a research aimed at the distribution of the temperature on the circular saw blade body. The temperature was measured at two distances from the centre of the circular saw blade body (70 mm, 140 mm) by means of an infrared thermometer. Two circular saw blades with the diameter of 350 mm and a variable ad...

We carried out the measurement of the three components of the cutting force as a function of the modification of the depth of cut during the longitudinal turning process. The results show that if we increase the depth of cut, all three components of the cutting force shows increasing tendency, regardless of how much the cutting speed and feed speed...

The paper presents the experimental results of a research aimed at the distribution of the temperature on the circular saw blade body. The temperature was measured at two distances from the centre of the circular saw blade body (70 mm, 140 mm) by means of an infrared thermometer. Two circular saw blades with the diameter of 350 mm and a variable ad...

The influence of milling and sanding on surface morphology of beech and spruce wood is investigated in the paper. Wood morphology was assessed through roughness and waviness parameters. The experimental results showed that the two wood surface machining techniques studied differed in their impacts on the wood roughness and waviness. Lower roughness...

In this paper, there are presented results of the thrust force and torque moment obtained during drilling of S355J0 EN10027-1 (St52-3 DIN). In the experiments, there were used drills with ø12mm, ø16mm and ø20mm diameters and with angles of main cutting edges 49°, 54° and 59°. The feed rates were 0.10mm, 0.15mm and 0.20mm, revolutions of drills were...

The article deals with the issue of drilling holes in material C45 (steel). Specifically evaluates the thrust force with respect to change feed per revolutions (0.20mm, 0.28mm and 0.40mm) and back angle of the drills (8°, 10° and 12°). In the paper are present results for drills with ø20mm diameters and with angles of main cutting edges59°. Revolut...

The paper presents the experimental results of a research aimed at the distribution of the temperature on thecircular saw blade body. The temperature was measured at four distances from the centre of the circular saw blade body (60 mm, 70 mm, 80 mm, 90 mm) by means of an infrared thermometer. Three circular saw blades with the diameter of 350 mm an...

The knowledge of the natural frequencies’ values of circular saw blades is necessary to determine the mini mal critical rotational speed in which they can work with required stability. Moreover, testing the circular saw bl ades with more complicated shapes, e.g. which have additional holes inside blades for cleaning knifes or additional indirect te...

This work investigates the influence of beech wood mechanical treatment on specific surface properties of this wood. The aim of this part has been to recognise milling and sanding-induced physical modifications of beech wood surface morphology assessed through roughness and waviness parameters. The experimental results show different impacts of di...

The aim of the second part has been to investigate the influence of beech wood mechanical treatment on wood surface wetting with standard apolar and polar-apolar liquids. Experimentally measured contact angles formed by drops situated on different treated beech wood surfaces were used for calculation of wood surface free energy together with its di...

Different methods for the empirical determination of the natural frequencies of circular saw blades are presented. Stationary methods, such as the harmonic and impulse tests, are discussed and the results of related comparison are given. The comparison of the methods revealed their degree of practical usefulness and their accuracy in determining na...

In this paper results of comparison of characteristic resonant frequencies of circular saw blades as a function of the saw clamping diameter from the impact test are presented. Obtained results revealed that proportionally with the increase of the saw clamping diameter also the dynamical stiffness of the saw blade increased. As a consequence of tha...

This contribution presents results of an experimental research on sanding. With a sample of oak being the experimental material, sanding was carried out on radial, tangential and transversal surface of the piece. The impact force was changed on three levels (21 N, 41 N and 58.5 N), the grain size of sanding belt in four levels (40, 60, 80, 100). Th...

Lateral oscillation of saw discs is quite an unwished situation and causes adverse effects not only on the work piece but also on the tool. The paper deals with the problem of circular saw blade oscillation and with the effect of modifying the natural frequency and critical rotational speed of the circular saw blade body. A calculation and experime...

Oscillation is an unwelcome state as it has adverse effects not only on the work piece but also on the tool. This paper deals with the problem of circular saw blade oscillation and the effect of modification of the circular saw blade body on the natural frequency as well as on the critical rotational speed. The calculation and experimental investig...

In most cases high cutting speed is used when cutting wood by circular saw. This results in oscillating of circular saw blade, which may lead to destroying the tool, machine or hurting the operator. The aim of this paper is to show that it is possible to apply any of the methods used in the research as an equivalent method for obtaining the values...

Authors focus on an issue of cutting medium effect on possibilities to reduce energy consumption in a cutting process. The method was designed to monitor an energy consumption and factor of friction under different cutting media at turning. First, measured data was statistically processed and then, using software Mathematica this data was overlappe...

The suitability of modern fracture mechanic theory was proved for the estimation of the cutting force and the cutting specific resistance. This paper shows modification of Ernst-Merchant theory and its application for determination some other properties of wood sample. This theory is acceptable for evaluation of shear yield stresses and shear plane...

Drilling (boring) is one of the oldest technologies of machining in all of the branches of production industry. Of course, it is an integral part of wood cutting technologies in the furniture production industry, in which are used mainly chip boards, building industry, wooden building, as well as in packing and transport materials production. It is...

In most cases, the cutting of wood is proceeded at high feed speed and high cutting speed of the circular saw blades. The circular saw blades teeth rotate in outer ambient and thus are source of noise with unadvisable effects on working environment. The results of the measuring the noise level of three structuraly different circular saw blades are...

Machining of wood by cutting tools is very closely connected with forces that determinate parts of woodworking machines mainly feed mechanism and shanks of tools too. Feed force consumed during woodworking is one of indicators of the process efficiency. This paper offers some results of measuring of this parameter by original device and methodology...