196 research outputs found
TECHNOLOGICAL PRODUCTION PROCESS OF FOLDING LONGBOARD
No full textNa tržišču obstaja veliko število rolk, ki se med seboj razlikujejo po obliki in materialu iz katerega je narejena deska, od katerih pa je zelo malo zložljivih. V delu je prikazano snovanje in izdelava zložljive rolke, ki je lepša po obliki in zavzema manj prostora. Najprej smo v programu SolidWorks določili optimalno sestavo in usmerjenost furnirjev. Nato smo izdelali načrt izdelave v programu SolidWorks, v programu SolidCam pa izdelali G kodo za izrez deske na CNC stroju. Furnirske liste smo zlepili z epoksidnim in poliuretanskim lepilom. Uporabili smo bukov furnir, med katerega smo dodali tudi ojačitve iz ogljikovih vlaken. Tako smo dobili za 10% boljše lastnosti v vzdolžni in 50% v prečni smeri deske. Za sestavo obeh polovic rolke smo skonstruirali spoj iz aluminijastih vložkov na principu čepa in zareze.There is a large number of longboards on the market, which differ in shape and material from which the boards are made but among them very few are foldable. In the thesis folding roll that is more beautiful in shape and takes up less space compared to others was made. First, in the SolidWorks program, using finite element module, the optimum composition and orientation of the veneers was set. Then a production plan was created and with the SolidCam software the code for cutting the board on a CNC machine was generated. The veneer sheets were glued with epoxy and polyurethane adhesives. Beech veneer and carbon fibre reinforcements were used for board production. In this way 10% better properties in the longitudinal and 50% in the lateral direction of the board were obtained. For the assembly of both halves of the roll a compound made of aluminium inserts on the principle of plug and notch was constructed
Identification of damping of Spruce wood (Picea abies) under various levels of moisture content using time-scale decomposition
No full textThe damping of spruce wood is analysed at different moisture content levels for the first three vibration modes of tangentially and radially vibrating samples. Two methods were used to determine the damping. The first was the vibration envelope fitting as an improved version of the well-known logarithmic decrement, and the second was the newer and recently increasingly used wavelet transform. Both methods showed that the damping of spruce wood first decreases and then increases with moisture content, with the damping in the first vibration mode being about 9% higher in the radial direction than in the tangential direction. In the second and third vibration modes, the damping in the tangential direction was higher than in the radial direction by about 10% and 8.8%, respectively. The measured damping factors from the envelope fitting had, on average, 15.9% higher values than those from the wavelet transform. It can be concluded from the results that the wavelet transform is more accurate for determining the damping factor, as it enables the decoupling of multi-degree of freedom systems if mode coupling is present
Determination of dynamic and static modulus of elasticity of beech plywood
No full textV raziskavi smo primerjali vrednosti dinamičnega in statičnega modula elastičnosti 7- in 11-slojne vezane plošče z različnimi kombinacijami usmeritve tkiva posameznih slojev furnirjev. Dinamični modul smo določili iz lastnih frekvenc prvega in drugega nihajnega načina nihanja, kjer smo uporabili Bernoulli-Eulerjevo enačbo, statični modul pa s 4-točkovnim upogibnim testom. Rezultati so pokazali, da ima vezana plošča največji modul elastičnosti pri usmeritvi tkiva zunanjega sloja 0°, nato pa z naraščanjem kota modul pada. Dinamični modul je od statičnega v povprečju za 12 % večji pri 7-slojnih ploščah in za 14 % pri 11-slojnih ploščah. Dinamični modul, določen iz druge lastne frekvence, je v primerih, kjer ni vpliva striga, enak modulu iz prve lastne frekvence, ko pa se pojavi vpliv striga, se modul zniža. Iz omenjene raziskave lahko potrdimo, da sta tako statični kot tudi dinamični način določanja modula elastičnosti vzorcev vezane plošče ustrezna, vendar pa je treba pri dinamičnem načinu preveriti vpliv striga.The study compared the values of the dynamic and static modulus of elasticity of 7- and 11-layer plywood with different combinations of the grain orientation of individual veneer layers. The dynamic modulus of elasticity was determined from the natural frequencies of the first and second vibration mode using the Bernoulli-Euler equation and the static modulus was determined using the 4-point bending test. The results showed that the plywood has the highest modulus of elasticity at the orientation of the wood grain of the outer layer 0°, and then the modulus decreases with increasing angle. The dynamic modulus is on average 12% higher than the static modulus for 7-layer boards and 14% higher for 11-layer boards. The dynamic modulus determined from the second natural frequency is equal to the modulus determined from the first natural frequency when there is no shear influence, but when the shear influence occurs, the value of the modulus decreases. From the above mentioned investigations it can be confirmed that both static and dynamic methods are suitable for determining the modulus of elasticity of plywood samples, but it is necessary to check the shear influence in the dynamic method
Application of failure criteria on plywood under bending
No full textIn composite materials, the use of failure criteria is necessary to determine the failure forces. Various failure criteria are known, from the simplest ones that compare individual stresses with the corresponding strength, to more complex ones that take into account the sign and direction of the stress, as well as mutual interactions of the acting stresses. This study investigates the application of the maximum stress, Tsai-Hill, Tsai-Wu, Puck, Hoffman and Hashin criteria to beech plywood made from a series of plies of differently oriented beech veneers. Specimens were cut from the manufactured boards at various angles and loaded by bending to failure. The mechanical properties of the beech veneer were also determined. The specimens were modelled using the finite element method with a composite modulus and considering the different failure criteria where the failure forces were calculated and compared with the measured values. It was found that the calculated forces based on all failure criteria were lower than those measured experimentally. The forces determined using the maximum stress criterion showed the best agreement between the calculated and measured forces
Influence of technological parameters on the quality of machined maple wood surface
No full textRaziskali smo vpliv tehnoloških parametrov na kakovost obdelane površine javorjevine pri premočrtnem odrezovanju. Eksperiment je bil sestavljen iz 2 delov. Najprej smo raziskali vpliv kota poteka tkiva, kjer smo spreminjali kot od 0° do 90° v stopnjah po 22,5° (0° pomeni radialno teksturo, 90° pa tangencialno). Cepilni kot rezila je znašal 20°, debelina odrezka pa 0,1 mm. Zatem smo proučili vpliv cepilnega kota rezila ter debeline odrezka na kvaliteto obdelane površinekoti so znašali: 5°, 15°, 25° in 35°debeline odrezka pa: 0,05 mm, 0,1 mm in 0,15 mm. Za vsako kombinacijo parametrov smo naredili 2 reza, pri vsakemu rezu pa smo z merilnikom hrapavosti naredili 2 meritvi na ranem in kasnem lesu in tako določili parametre Ra, Rz in Rmax. Ugotovili smo, da je najboljša kvaliteta površine pri kotu tkiva 22,5°, debelini odrezka 0,05 mm ter cepilnim kotom rezila 15°The influence of technological parameters on the surface quality of machined maple wood in the orthogonal linear cutting was studied. The experiment was carried out in 2 parts. First the impact of the tissue angle was studied, where the tissue angle ranged from 0° to 90° in stages of 22.5° (0° is radial texture and 90° tangential texture). The blade rake angle and the chip thickness was 20° and 0.1 mm, respectively. Then the influence of the blade rake angle and the chip thickness on the machined surface was studied. The rake angles were: 5°, 15°, 25° and 35°and the chip thicknesses: 0.05 mm, 0.1 mm and 0.15 mm. In both parts of the experiment 2 cuts for each combination were made, and after each cut 2 surface profiles on earlywood and latewood with surface roughness tester were made. Based on those measurements the parameters Ra, Rz in Rmax were determined. The results show that the best surface quality is at tissue angle of 22.5°, chip thickness 0.05 mm and the blade rake angle of 15°
Optimization of CNC technology in the manufacturing process of an artistic product
No full textV okviru diplomske naloge smo izvedli optimizacijo procesa obdelave umetniškega lesena izdelka na 3-osnem CNC stroju. V programu ArtCAM smo izdelali 3D model, njegovo površino smo triangulirali in tako ustvarili STL datoteko. To smo naložili v SolidWorks, kjer smo s programom SolidCAM določili parametre obdelave s skupinami operacij HSR in HSM. Ugotovili smo, da sta ti dve skupini najboljša izbira glede na obliko modela in sposobnosti izbranega CNC stroja, saj omogočata doseganje najboljšega razmerja med kakovostjo obdelovalne površine in časom obdelave. HSR in HSM ponujata več različnih operacij, ki so si različne po poti orodja in parametrih, ki jih lahko nadzorujemo. Operacije smo primerjali med sabo in ugotovili, da bi najboljše rezultate dobili pri izbiri HSR operacij »Contour Roughing« in nato »Rest Roughing« ter HSM operacije »3D Constant Step Over«. Izdelali smo G kodo za naš program.In this BSc. thesis the optimization of the manufacturing process of an artistic wooden product with a 3-axis CNC machine is carried out. The 3D model was first made in ArtCAM, as was the STL data that was later uploaded to SolidWorks. The parameters for the HSR and HSM processing were altered in SolidCAM. The findings show that a group of HSR and HSM operations are the best choice, considering the shape of the model and the capabilities of the machine, as the best ratio between the quality of the surface and the time needed for the operation is provided by these. Operations differ with regard to the tool path and parameters that can be adjusted. The operations were compared and the best results are achieved when the HSR operations “Contour Roughing” and then “Rest Roughing” are used and when the HSM operation “3D Constant Step Over” is used. The G code was made for our program
Reverse engineering in mechanical wood processing
No full textV nalogi smo preučili uporabo in natančnost vzvratnega inženiringa v procesu mehanske obdelave lesa, kjer smo za določevanje oblike obstoječih predmetov in izdelavo njihovih replik uporabili fotografiranje. Zajete fotografije smo obdelali v računalniškem programu Agisoft Photoscan, kjer smo poravnali fotografije v prostoru in ustvarili 3D modele izdelkov. Te smo nato uvozili v program SolidWorks ter z razširitvijo SolidCAM generirali G-kodo za računalniško krmiljeni stroj. Za izdelavo replik smo uporabili les hrasta, bresta in javorja, od katerih sta se za najprimernejša izkazala brest in javor, pri hrastu pa je bila zaradi njegove nekoliko bolj grobe strukture kakovost površine slabša. Na kakovost končne površine izdelka najbolj vplivajo svetloba, površina fotografiranega predmeta in izbira natančnosti poravnave fotografij v samem programu. Svetloba mora biti čim bolj enakomerna in zadostna. Za površino fotografiranega predmeta je zaželeno, da svetlobo odbija difuzno, ne zrcalno. Pri fazah poravnave v programu je dobro izbrati veliko natančnost, saj se posledično izboljša kakovost površine. Metoda vzvratnega inženiringa je v lesarstvu uporabna, saj je časovno učinkovitejša od drugačnih metod merjenja in 3D modeliranja.In the thesis the use and accuracy of reverse engineering in the mechanical woodworking process were examined. For acquiring the shape of existing objects photographing was used and the captured images were processed in the computer software Agisoft Photoscan, where photos were aligned in space and a 3D model created. Using SolidWorks and SolidCAM a 3D model was imported and a G-code for CNC machine was then generated. Oak, elm and maple wood were used to produce the replicas, where elm and maple proved to be the most suitable, while oak, due to its slightly coarser structure, produced worse surface quality. The quality of the finished surface of the product is most affected by the light, the surface of the photographed object, and the choice of the alignment accuracy of the photos in the software itself. The light should be as uniform as possible and sufficient. When photographing the surface of the object, it is preferable that the light reflecting off said object is diffused and not reflected. It is advisable to choose a high degree of precision in the alignment stages of the program, as the resulting surface quality is improved. The reverse engineering method is useful in woodworking because it is more time efficient than different methods of measurement and 3D modeling
The use of plywood for construction of a distributed mode loudspeaker
No full textV nalogi smo preučili možnost uporabe furnirne vezane plošče, kot trajnostnega materiala za konstrukcijo panelnega zvočnika. Uporabnost tega materiala smo primerjali z umetnim materialom (polietilenom), na podlagi meritev frekvenčnega odziva plošče in ugotovili, da ima furnirna vezana plošča ob enakem vzbujanju večjo povprečno zvočno jakost in bolj enakomeren frekvenčni odziv, polietilenska plošča pa ima večjo zvočno jakost pri frekvencah pod 100 Hz. Preverili smo tudi vpliv postavitve vzbujevalnika in ugotovili, da postavitve, ki so si blizu, ne izkazujejo bistvenega vpliva na frekvenčni odziv. Eksperimentalne meritve smo verificirali z računalniško simulacijo z metodo končnih elementov v programu Ansys in ugotovili, da je ujemanje zadovoljivo.In the thesis the use of plywood for the construction of a flat panel (DML) loudspeaker was examined. With measurements of the frequency response, the usability of plywood was compared to the use of a synthetic material (polyethylene). It was found that plywood produces a higher average sound pressure level and a flatter frequency response than polyethylene, but the latter produces higher sound pressure at frequencies below 100 Hz. It was found that placements of the audio exciter which are not dramatically different between each other do not have a meaningful impact on the frequency response of the flat panel loudspeaker. A simulation model was constructed in Ansys Mechanical, and the experimental data was compared to the results of the finite element analysis. It was found out that the relationship between the model and experimental data was satisfactory
Strength analysis of planar composite element with the finite element method
No full textV nalogi smo ugotavljali korelacijo med numeričnim izračunom trdnosti kompozitnega elementa in eksperimentalno dobljenimi vrednostmi pri štiri točkovnem upogibu. Numerično analizo smo naredili z metodo končnih elementov (FEM) s programom Solidworks Simulation, kjer smo vzorce modelirali kot linearno elastičen ortotropen kompozitni element. Izdelali smo vezane plošče z različno usmerjenimi sloji bukovega furnirja in različnim številom slojev. Vzorce iz vezanih plošč smo izrezali pod različnimi koti, tako, da je bil prvi sloj vzorca pod različnim kotom glede na vzdolžno usmerjenost vzorca. Lastnosti materiala za definiranje materiala v simulaciji smo določili eksperimentalno z mehanskimi preizkusi bukovega furnirja debeline 1,5 mm in vzdolžno vezanih vzorcev večjih debelin. V povprečju je bil rezultat računalniške simulacije štiri točkovnega upogiba 55% rezultata mehanskega preizkusa in v nobenem primeru ni presegel vrednosti maksimalne obremenitve v mehanskem preizkusu.The correlation between numerically computed strength of composite element and experimentally acquired values from four point bending test was researched. Numerical analisys was made with the finite element method (FEM) with Solidworks Simulation software, where samples were modeled as linear elastic orthotropic composite element. Plywood panels with different orientations of veneer plies and different numbers of plies were made. Samples were cut from plywood boards at different angles so that the first ply of the sample was at an varying angle compared to the length of the sample. Material properties for simulation were obtained experimentally with mechanical tests of beech veneer of 1,5 mm thickness and parallely glued samples of bigger thicknesses. The result of computer simulation was on average 55% of the result of mechanical test and in no case it didn\u27t exceed value of maximum load in mechanical test
Optimization of CNC technology in the manufacturing process of a wooden product
No full textV diplomskem delu smo optimizirali tehnologijo izdelave lesenega umetniškega izdelka – lesene knjige. Knjigo smo najprej modelirali s programom SolidWorks, nato pa smo s programom SolidCAM generirali G kodo za krmiljenje računalniško podprtih strojev (CNC). Pri izdelavi G kode smo med seboj primerjali različne načine obdelave površin, ki jih nudi program SolidCAM. Izdelek smo najprej obdelali z grobo obdelavo, nato pa še s fino. Pri simulaciji z grobo obdelavo smo ugotovili, da v našem primeru niso vsi načini grobe obdelave enako uporabni, saj se lahko časi obdelave med seboj močno razlikujejo. Podobno smo ugotovili pri fini obdelavi izdelka, kjer se pri enaki kakovosti obdelane površine časi obdelave med seboj razlikujejo.In this diploma thesis the technology for the production of a wooden art product, a wooden book, was optimized. First, the book was modeled with SolidWorks software, and then using SolidCAM software G code was generated to control computer numerical controlled machines (CNC). In the programming different processing methods were compared. The product was first machined with rough milling and then with fine milling. In the rough milling all processing methods that the program provides were examined. It was found that all rough processing methods are not equally useful in our case, since machining times can vary greatly. Similarly, it was found out in the fine milling of the product that the milling times differ greatly for different milling technologies, considering the same final surface quality
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