|
|
Analyssis of conventional technologies for sawing.
Kašpar, Ladislav ; Osička, Karel (referee) ; Zemčík, Oskar (advisor)
In this work is a survey of conventional method of cutting of material used on common technological routine processed.Principle, used instruments, which are disposed and described in detail and example of used machines and its basic technical parameters are mentioned in each way of material division.In the end examples of aplications of these methods in production practise and summary of advantages and disadvantages of its use is mentioned.
|
|
|
On the analysis of thin-wall parts sawing
Spáčil, Radek ; Dvořáková, Jana (referee) ; Píška, Miroslav (advisor)
Master‘s thesis deals with sawing of the thin-walled parts with high speed steel slitting saw. At first the most used conventional and unconventional possibilities of materiál cutting are described by a form of search. The next chapter describes forces arising from splitting saw machining, including their dependence on a specific cutting force, a chip cross section and a engagement angle. The second part of the thesis deals with the technological improvement of the cutting process, where three possible solutions are considered – geometry of the cutting tool, PVD coating deposition of the cutting tool and process fluid change. In the experimental part non coated slitting saw with burrs, non coated deburred slitting saw and coated slitting saws are compared. Used coatings were Ti(C,N), Cr-Al-Si-N, Al-Cr-B-N, and TripleCoating Cr, which is consisting of three layers TiN + (Al,Ti)N + Cr-Al-Si-N. The experiment has shown that the cutting forces inceases as the edge radius and wear level of the cutting tool increases. Coated cuttung tools has shown lower differences between the first and the last cut. Slitting saws have been also used in real cutting process to verify experimental results.
|
|
|
Vliv modifikace bukového dřeva na parametry obrábění
Vencl, Jakub
The Bachelor´s thesis is focused on the observation of effect of beech wood modification on the energy parameters of chip machining. It is about a comparison of modifications of beech, i.e. Lignamon and Bendywood which will be compared to native beech. In the case of native wood, the results of experimental measurements were also compared to results calculated with conventional methods. The methods which were used were: Technological-statistical and Analytical method. The primary investigation was cutting force. It was found that modification of beech wood does not have a statistically significant effect on machining parameters. In a comparison of two theoretical methods in the case of native wood was found that the Technological-statistical method had better sameness with experiment. The disadvantege of those methods is that they cannot be used for modified wood.
|
|
|
Energetické parametry při formátování aglomerovaných materiálů
Pitrman, Dobroslav
This bachelor's thesis is devoted to energy parameters while formatting agglomerated materials (MDF, Particleboard, OSB). This is primarily the effect of chip thickness on the cutting and sliding force size when cutting individual materials. During the experiment, different saw blades with different body modifications were used. The collected data were compared with the measured data and the calculated value of the average chip thickness. The dependence of the size of the cutting and sliding force on the mean chip thickness was demonstrated. As the thickness of the chip increased, so did the values of the individual forces. The effect of the machined material on the cutting force was quite significant. The internal structure of individual materials mainly influenced the cutting force. The smallest cutting force was measured with MDF and the largest with OSB. The influence of adjustment of the saw blade did not have such a significant effect on the size of the cutting force as the type of material being cut. Comparing all of the discs that had been used, the lowest cutting force measured was, on average, done by the discs with copper rivets. It was also statistically proven to be dependent on the size of the cutting force.
|
|
|
Kvalita řezné spáry při podélném rozmítání dřeva speciálními pilovými kotouči
Kryl, Jan
The thesis is focused on qualities problems of the cutting kerf rip saw-blade at along grain cutting native wood. The effect of vibrations of circular saw-blades and feed rate of shift of workpiece on the quality of the kerf has being investigated. The basic parameters of evaluation of the surface were mentioned in theoretical part of this thesis. Also, the methods of assessing the quality of the surface of scattered timber are analyzed inside this thesis. There is also described suitability of different measurement methods, which have been used, due to the nature of solid wood. Finally, constructional modifications of scattering discs are characterized here. At practical part of this thesis is compared the quality of surface of wood scattered with using of saw-blades from company of PILANA. Discs with standard profile of tooth and special toothing of shaped keg were used.
|
|
|
Pilový kotouč v procesu podélného řezání materiálů na bázi dřeva
Veselý, Přemysl
In this dissertation thesis there is listed characteristics of circular saw blades, their distribution, influence of construction adjustments on final behavior of blade in the process of machining, problematic of oscillation of blades a mutual interaction among quality of machined surface, noise and dust. The thesis covers the problems of oscillation of circular saw blades as when idling and operating - the cutting process; and by the use of three circular saw blades with different construction modifications. These aforementioned construction measures are also compared to each other due to the implementation of standard construction saw blades not only from the perspective of oscillation, but also from the perspective of the roughness of the machined surface and the analysis of wood waste generated during cutting and noise. In the theoretical part there is an analysis of available literature and scientific theses. It outlines the particular publications devoted to methods of determining the shapes of oscillation, determining critical, resonant and recommended speed, blade constructions, including possible modifications, the theory of cutting saw blades including determining the size and shape of the splints and the effects of noise on the work environment. An important part of this work is methodology involving direct measurements for detection of unstable states of discs (resonance and critical speed. In this section it is further evaluated measuring of the oscillation of the test saw blade and verification of the proposed methodology with a different and practiced, commonly known method, so called cold shapes: The author also seeks to explore and determine the effect of different tooth pitch and method of execution of slots along with soundproofing grooves on noise levels, the resulting quality of the machined surface of various wood. The generated waste is then analyzed for splitting wood particles in particular size group with the percentage of each chip. The results of the experiment are in discussion confronted with the available scientific theses, taking into account with normal operating conditions, of which the conclusion is drawn.
|
|
|
Mechanika procesu řezání pilovým kotoučem
Hlásková, Luďka
The main aim of the dissertation thesis is to develop an alternative methodology for the calculation of the cutting resistance, which is based on the fracture properties of the wood, with the incorporating of the Ernst-Merchant theory into the conditions of the circular saw blade. Cutting resistance is an important property of machined material that affects the amount of energy consumption during machining. The energy effects can be calculated theoretically using conventional methods based on the specific cutting resistance, which is a function of many factors. These coefficients are derived from experiments conducted in the 1950s and are therefore currently inaccurate. In contrast to traditional computing methods, the new model uses only two main parameters: fracture toughness and shear yield stress. Based on the Ernst-Merchant diagram, the magnitudes of the forces affecting the workpiece and tool are calculated. Further, this model is depend on the determination of the internal work for bending and subsequent separating of the chip, on the energy needed to overcome the friction between the workpiece and the blade of the tool and last but not least, on the specific work for forming the new surface of the workpiece. Experiments were carried out on the laboratory equipment designed for the saw blade research, and one partial experiment was executed in cooperation with Gdańsk University of Technology using a frame saw. Samples of spruce wood (Picea Abies) and beech wood (Fagus Sylvatica) were used. The results calculated by the new method were compared with the experimentally measured data and the results calculated by the conventional methods. The main parameters of the proposed method are founded on the made measurements, so the newly designed calculation model shows the best match with the experimental data. From the conventional methods, only the Technology-Statistical Method had a better match with the experiment. Further experiments were used to determine the cutting parameters for modified beech wood samples (Bendywood, DMDHEU and Lignamon). For all the measurements made, the basic relations for the calculation of the fracture characteristics of the material (fracture toughness and shear strength, without complicated fracture tests) were derived for the axial-perpendicular saw blade cutting model. The data obtained could be applied to calculate the energy effects of other types of wood machining.
|
|
|
On the analysis of thin-wall parts sawing
Spáčil, Radek ; Dvořáková, Jana (referee) ; Píška, Miroslav (advisor)
Master‘s thesis deals with sawing of the thin-walled parts with high speed steel slitting saw. At first the most used conventional and unconventional possibilities of materiál cutting are described by a form of search. The next chapter describes forces arising from splitting saw machining, including their dependence on a specific cutting force, a chip cross section and a engagement angle. The second part of the thesis deals with the technological improvement of the cutting process, where three possible solutions are considered – geometry of the cutting tool, PVD coating deposition of the cutting tool and process fluid change. In the experimental part non coated slitting saw with burrs, non coated deburred slitting saw and coated slitting saws are compared. Used coatings were Ti(C,N), Cr-Al-Si-N, Al-Cr-B-N, and TripleCoating Cr, which is consisting of three layers TiN + (Al,Ti)N + Cr-Al-Si-N. The experiment has shown that the cutting forces inceases as the edge radius and wear level of the cutting tool increases. Coated cuttung tools has shown lower differences between the first and the last cut. Slitting saws have been also used in real cutting process to verify experimental results.
|
|
|
Kvalita řezné spáry při dělení umělého kamene
Jálová, Lenka
The work is focused on the characteristic, properties and uses of artificial stone (category Solid surface) in furniture manufacturing. Beside other things, work deals with the process of machining, circular saw blades, water jet machining and methods for evaluating the kerf quality. The main goal is to assess the kerf quality for both different technologies of cutting and different Solid surface materials. Finally, the work is focused on assessing the significance of the circular saw blades geometry and their impact on the quality of machined surface.
|
|
|
Pilový kotouč v procesu podélného řezání materiálů na bázi dřeva
Veselý, Přemysl
In this dissertation thesis there is listed characteristics of circular saw blades, their distribution, influence of construction adjustments on final behavior of blade in the process of machining, problematic of oscillation of blades a mutual interaction among quality of machined surface, noise and dust. The thesis covers the problems of oscillation of circular saw blades as when idling and operating - the cutting process; and by the use of three circular saw blades with different construction modifications. These aforementioned construction measures are also compared to each other due to the implementation of standard construction saw blades not only from the perspective of oscillation, but also from the perspective of the roughness of the machined surface and the analysis of wood waste generated during cutting and noise. In the theoretical part there is an analysis of available literature and scientific theses. It outlines the particular publications devoted to methods of determining the shapes of oscillation, determining critical, resonant and recommended speed, blade constructions, including possible modifications, the theory of cutting saw blades including determining the size and shape of the splints and the effects of noise on the work environment. An important part of this work is methodology involving direct measurements for detection of unstable states of discs (resonance and critical speed. In this section it is further evaluated measuring of the oscillation of the test saw blade and verification of the proposed methodology with a different and practiced, commonly known method, so called cold shapes: The author also seeks to explore and determine the effect of different tooth pitch and method of execution of slots along with soundproofing grooves on noise levels, the resulting quality of the machined surface of various wood. The generated waste is then analyzed for splitting wood particles in particular size group with the percentage of each chip. The results of the experiment are in discussion confronted with the available scientific theses, taking into account with normal operating conditions, of which the conclusion is drawn.
|
guest ::
