THÔNG TIN TÀI LIỆU
uu MINISTRY OF EDUCATION AND TRAINING MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT VIETNAM NATIONAL UNIVERSITY OF FORESTRY NGUYEN THI LUC DETERMINING OPTIMAL PARAMETERS OF VERTICAL BAND SAW IN AUTOMATIC WOOD CHAINSAW Speciality: Mechanical Engineering Code: 9520103 SUMMARY OF THESIS DOCTOR OF TECHNICAL HANOI - 2021 Thesis is completed at: VIETNAM NATIONAL UNIVERSITY OF FORESTRY The Doctoral Advisers: PGS.TS Duong Van Tai Reviewer 1: Reviewer 2: Reviewer 3: The thesis will be defended at the School-level Thesis Judging Committee at: Vietnam National University of Forestry At ……hour day month year 2021 The thesis can be found at the library: National Library of Vietnam Vietnam National University of Forestry Library PREAMBLE Urgency of the research problem In 2016, the Ministry of Science and Technology assigned the Forestry University to lead a state-level project on "Research, design and manufacture automatic wood sawing equipment lines with a productivity of -4 m3/h of wood has finished products” code ĐTĐL.CN-10/16 The project has designed and manufactured an automatic wood sawing line, but the project has only stopped at the design, manufacturing and testing part of an automatic wood sawing line model Has not reseach the dynamics of vertical band saw in cutting process and optimize the parameters of the equipment in the system In the automatic wood sawing line, the vertical circular saw is an important device that greatly affects the ability and working efficiency of the line It is very necessary to research and optimize the technical parameters of vertical circular saws in order to improve productivity and product quality Stemming from the above issues, I choose and carry out the thesis topic: " Determining optimal parameters of vertical band saw in automatic wood chainsaw " Research objective Building models, setting up dynamic equations, vibration equations of vertical band saw blades, surveying dynamic equations, determining some optimal parameters of vertical band saws in automatic sawing lines, to improve productivity and product quality New contributions of the thesis - Built a dynamic model of vertical band saw, established and investigated the system of differential equations of motion and the vibration equation of the saw blade The survey results have determined the values of some geometrical, kinetic and dynamic parameters as the basis for the design and manufacture of vertical band saws - Has been built a theoretical basis for setting up and solving multi-objective optimization problems with many influencing parameters, which can be used for similar problems For vertical circular saws, has been control parameters of the optimization problem have been selected with objectives, in which using the similarity and dimensional methods to build the correlation function According to this method, the number of basic experiments has been reduced by more than times, thus reducing the experimental, while still ensuring all parameters change at the necessary levels - Has been built a dynamic experimental research model, some dynamic parameters of vertical band saws have been determined to serve the survey problem and verify the established theoretical computational model - By empirical research, the thesis has determined the values of the parameters when sawing for Ash wood (Fraxinus) are: initial tension S0= 1876(N); cutting speed v = 55 m/s; pushing speed uc = 0,123 m/s; saw blade cutting angle δ = 580, wood diameter d = 62 cm With these above parameters, the specific energy cost Ar = 1,72 kWh/m2 and the surface roughness of sawn board Ramin =0,173 mm, then the average sawn yield was calculated Πv= 3,12 (m3/h) ˃ [Πv] = 3(m3/h) Scientific significance of the research results of the thesis topic - From the system of kinematic equations set up, survey the graph of velocity and acceleration, determine the nonuniform coefficient (ψ) of angular velocity, the dynamic coefficient (kđ) Investigate the influence of the flywheel moment of inertia (Ibđ) on the non-uniformity coefficient, the dynamic coefficient Investigate the effect of saw blade tension (S0) on specific energy cost and sawn circuit quality The survey results have built the correlation chart between Ibđ and ψ, and the table S0 with the shear force resistance of each type of wood (kc) That is the scientific basis for determining reasonable values of some parameters of vertical band saws - From the vibration equation of the saw blade, survey the graph, determine the horizontal vibration amplitude of the blade as a basis for assessing the quality of the sawn board surface - Applying the theory of similarity and dimensions in experimental research has built a general method to set up and solve the problem of optimizing the parameters of vertical band saws This method can be used for problems with many similar influencing parameters in engineering The practical significance of the thesis topic - The research results of the thesis are used for the design, manufacture and completion of vertical band saw in automatic wood sawing lines by the state-level project code ĐTĐL.CN-10/16design and manufacture - The results of the thesis can be used as a reference for research units and vertical band saw manufacturers Chapter OVERVIEW OF RESEARCH ISSUES 1.1 Overview of research works on optimization of vertical band saws in Vietnam and around the world The research on vertical band saw in Vietnam is still very little, especially on optimization issues, there are almost no works that fully consider the objectives with many influencing parameters, for the sawing object wood from Vietnam In the world, there are many types of vertical band saws in automatic wood sawing lines that have been applied in practice, but the announcements about the optimal calculation results of vertical band saws are still limited 1.2 The subject of the thesis research 1.2.1 Research equipment Vertical band saw in automatic wood sawing line designed and manufactured by the state-level project code ĐTĐL.CN-10/16 The structure diagram of the vertical band saw is shown in Figure 1.1 1- Saw blade; 2- Active flywheel; 3- Passive flywheel; 4- Hydraulic saw blade tensioning mechanism; 5- Saw blade stabilizing mechanism; 6- Saw blade stabilizing mechanism; 7- Saw blade stabilizing mechanism; 8- Flywheel cleaning mechanism; 9- A woode rickshaw; 10 - Electric motor; Figure 1.1: Structure diagram of vertical 11- Bracket system; band saw 12 - Passive pulley; 13 - Active pulley 1.2.2 Materials put into sawing According to the material design of the automatic sawing line, designed and manufactured by the state-level project, are imported or domestic plantation timbers with diameter from 30cm to 80cm, log length ≤ 4m, wood group from group to group Based on the test results usage needs, the most suitable type of wood for the automatic sawing line is Ash wood (Fraxinus) imported from Europe with a diameter of 30÷80cm, this is a type of wood with high density medium hardness 1.3 Research content In order to achieve the objectives set out, the thesis proposes the following research contents: 1.3.1 Determination of basic parameters of vertical band saw according to working conditions - Build and investigate the dynamic model of vertical band saw Based on safety and stability conditions to determine some structural and technical parameters; - Build and survey the horizontal vibration model of the saw blade to find out the causes affecting the surface quality of sawn boards From there, a solution to reduce the horizontal vibration of the saw blade is proposed 1.3.2 Determine the optimal value of some parameters according to the criteria to evaluate the efficiency and quality of the sawing process - Analysis and selection of economic and technical criteria to evaluate the efficiency of using vertical band saws in the sawing process; - Determine the influencing parameters and select the control parameters of the optimization problem; Computational modeling of indicators according to control parameters, by multi-factor experiment and solve the conditional multi-objective optimization problem 1.4 Research methods 1.4.1 Theoretical research methods From the structure and operating principle of vertical band saw, using the method of multi-object system mechanics, the method of converting the solutions of differential equations to order form, the method of dissociation of variables, and Hamilton's principle to model and set up a system of differential equations and solve the set of differential equations Use Matlab - Simulink software to investigate the differential equations 1.4.2 Experimental research methods The method of measuring the quantities studied in the thesis is carried out according to the method of measuring non-electrical quantities by electricity The content of the method as well as the processing of experimental results are presented in the documents [3], [13], [24] Mathematical statistical methods, similarity and dimensional methods The planning and organization of experiments as well as the processing of experimental data are clearly presented in documents [1], [2], [13], [24] The application of the above research methods will be presented in detail in the next chapters when conducting research on each content Chapter BUILDING MODEL, SURVEYING THE DYNAMIC AND VIBRATIONAL PARAMETERS OF VERTICAL BAND SAW BLADE 2.1 Set up differential equations of motion The dynamic diagram of the sawing process is shown in Figure 2.1 a) Kinetic diagram b) Equivalent dynamic model Figure 1: Dynamic diagram of vertical band saw In order to build the dynamic calculation diagram of the system, we have to make the following assumptions: + The active and passive flywheels are absolutely rigid, the connection between the flywheel and the saw blade is a hold, stop and honolom (geometry); + Ignore the aerodynamic drag of the flywheel system when turning + The connections between the axes are the links of the belt drive and the saw blade, assuming they are elastic elements operating within the linear limit + The wheels of the wooden clamping mechanism (woode rickshaw) roll without sliding on the rails and ignore the resistance of the air + For wood put into sawing, there is physical and mechanical homogeneity regardless of the sawing position on a log + With the saw blade, the parameters of saw opening, sawtooth angles and tooth pitch are uniform With the above assumptions, the thesis establishes a dynamic model of the system as shown in Figure 2.1 Set up the OXYZ coordinate system, the origin at the center of the active flywheel 1; OY in the direction of movement of the woode rickshaw; OX is horizontal; OZ in the vertical direction In which the shafts are fitted with belt pulleys and the flywheel of the band saw, which rotates only around fixed axes, are placed on bearings with a resisting moment (rolling friction) MT The system consists of four elements that can be considered as solid bodies, whose motions are different, but which are linked together to form a sawing process Those object are: 1-Axis No I, (including motor shaft and active belt pulley) positioning parameter is rotation angle φ1(t); 2-Axis No II, (including shaft, passive belt pulley and active flywheel of saw blade) positioning parameter is rotation angle φ2(t); 3-Axis number III, (including shaft and passive flywheel of saw blade) positioning parameter is rotation angle φ3(t); 4- Woode rickshaw, reciprocating motion in the direction of OY axis, positioning parameter is displacement y(t) In Figure 2.1, the axes (I), (II) and (III) have fixed positions, they only rotate around fixed bearings Shaft III does not rotate, is kept in a stable balance position by hydraulic system No To establish this dynamic relationship, the thesis uses the Lagranger equation of the second type: (2.1) So the system has four interpolated coordinates that are wide enough to determine the position, we choose those coordinates as φ1, φ2, φ3 and y q = [φ1, φ2, φ3, y ]T (2.2) We get a system of differential equations oscillating around the equilibrium position: (2.3) Inside: Input parameters are as follows: I1 - Moment of inertia of shaft I with active belt pulley; I2 - Moment of inertia of shaft II with passive belt pulley and active flywheel; I3 - Moment of inertia of shaft III and passive flywheel; c1, c2 - Stiffness of belt and band saw blade; k1, k2 - Vibration resistance coefficient of belt and saw blade; R1, R2, R3, R4 Radius of active pulley, passive pulley, active flywheel and passive flywheel (R = R4); mxg - Weight of rickshaw and timber; MT1, MT2, MT3 - Frictional moment on I axis; II and III; Mđc - Torque of electric motor shaft; Mc - Shear resistance moment of shearing force Pc with respect to the flywheel shaft; Fms - The friction force of the track with the wheel; Qy - The shear resistance of the wood in the Oy direction; Fk - Trolley traction force The output parameters are: φ1, φ2, φ3 - Rotation angle of axes I, II and III; - Rotation velocity of axes I, II and III; - Rotation acceleration of the axes I, II and III; - Acceleration in the reciprocating motion of the cart 2.2 Survey dynamic parameters during sawing process a Survey content The content of the survey is to solve the system of dynamic equations (2.3) with the help of Matlab- Simulink software with the output of rotation velocity and rotation acceleration of axes From the survey results, the coefficients (kđ) and (ψ) corresponding to the values of some influencing parameters (inputs) will be determined According to the conditions of safety and stability, the necessary values of the influencing parameters will be determined to design and manufacture the parts of the saw With the input parameter table when calculating for sawing Ash wood in Table 2.1, the survey results of the speed and acceleration of axis II are obtained as shown in Figure 2.2 Table 2.1: Table of input parameters of the dynamic equation Figure 2: Graph showing rotation velocity and rotation acceleration of axes I and II during sawing Result of survey graph of rotation velocity and rotation acceleration on active flywheel mounted shaft II: ω2max=129; ω2min=112; ω2tb=121 b The results of the investigation of the dynamics equation To evaluate the degree of non-uniformity of the machine's rotation, we use the non-uniformity index of the angular velocity, which is determined by the ratio of the rotational speed of the guide: (2.4) With: : ; In mechanical engineering, the allowable value of ψ for each type of motor is specified within a limit as follows:[ψ]=[0.1÷0.5]; Carrying out the above survey and calculation process when sawing some other types of wood, we get the results recorded in Table 2.2, namely: 11 rotational speed of the whole I-axis, making the electric motor unstable, leading to a reduction in the life of the electric motor and large energy consumption b Result of surveying the transition process of vertical band saw The dynamic coefficient in the transition period is calculated by the expression kđ = (Mđ + Mt) / Mt, where Mt is the moment on axis I during steady motion without shear, Mt= Ɲđc/ω10 = 60000/115=521,74 (Nm) kd M d M t 10, 42 521,74 1,019 kd Mt 521,74 (2.5) By similarly examining the kđ coefficient during the transition when sawing other types of wood shown in table 2.3, we will also get kđ < – ensuring the safety of the saw Table 3: Calculation results of kđ dynamic coefficients for each type of wood Type of Iron wood Beechwood Ash wood Pine wood (Castanopsis (Fraxinus) (Pinaceae) wood (Erythrophleum) tonkinensis Seen) 1,0201 1,02 1,019 1,0155 kđ The results show that the coefficient kđ is smaller than the allowable coefficient, so the saw with the given parameters is guaranteed to cut the above types of wood 2.4 Investigate the influence of the flywheel moment of inertia on the rotation velocity nonuniformity coefficient ψ and the dynamic coefficient kđ a Effect of moment of inertia on rotation velocity nonuniformity coefficient According to the analysis and calculation results in Section 2.1b, we see that the rotation velocity uniformity coefficient ψ calculated has a large difference when sawing different types of wood (table 2.2) From there, we see the need for a solution to smooth the motion of the saw One of the most effective solutions is to determine the moment of inertia of the flywheel according to the condition (2.6): (2.6) The relationship between the moment of inertia of the flywheel and the nonuniform angular coefficient of rotation is shown by expression (2.7): ( 2.7) Equation (2.7) shows that the nonuniformity coefficient ψ is inversely proportional to the moment of inertia of axis II With known data according to design documents, when sawing other types of wood, we also have correlation charts ψ = f(I 2) and shown in Figure 2.5 12 If we choose [ψ] = 0.5, then according to the graph of Figure 2.5, we have: When sawing Ironwood (Erythrophleum), I2 > 70 (kg.m2); When sawing Beechwood (Castanopsis tonkinensis Seen), I2 > 34 (kg.m2); When sawing Ash wood (Fraxinus), I2 > 16 (kg.m2); When sawing Pine wood Pinaceae I2 > (kg.m2) Figure 2.5: Correlation graph (I2) when sawing some types of wood b Effect of moment of inertia on the dynamic coefficient kđ The expression for the relationship between the rotation acceleration and the moment of inertia of the flywheel according to the expression (2.8) (2.8) As we know ω2tb = const (with a predetermined value when designing the machine), so has a value proportional to ψ, so it is also inversely proportional to I2 When increasing I2 will make ψ decrease, that is, make the machine move more uniformly and the acceleration decrease, leading to a decrease in Mđ and coefficient kđ as well 2.5 Effect of flywheel moment of inertia on energy cost According to the results of solving the system of equations (2.3) in section 2.1, it shows that the angular velocities of the axes in the two cutting and non-cutting phases have different values (Figure 2.2 and Figure 2.3), thus the energy consumption in the two phases these stages are also different The energy expenditure in a sawing cycle will be: (2.9) From (2.9) we see that the energy cost in each sawing cycle is ratio proportional to I2 Comment: According to the results of calculation and analysis in sections 2.3 to 2.5, the moment of inertia of the flywheel has a great influence on the quantities used to evaluate the durability (kđ), stability (ψ), cutting capacity (Ac) and energy cost during sawing (Ar) In which ψ, kđ and shear capacity (Ac) are technical quantities, and Ar- in terms of economics Therefore, when designing and manufacturing vertical band saws, 13 the moment of inertia of the flywheel Ibd needs to be determined according to the condition ψ, kđ is less than the allowable value 2.6 Horizontal saw blade vibration a Horizontal vibration pattern of vertical band saw blade Horizontal vibration pattern is equivalent to figure 6a) a) Modeling of external forces b) Components of internal Figure 2.6: Horizontal displacement diagram force of vertical band saw blade cutting branch Where: S0- Initial tension of the saw blade; Px - Horizontal shear force component (0x); v – The speed of the saw blade; uc - Speed of pushing wood in the direction (0y); L – Distance between flywheel shafts; Let φ and φ+Δφ be the angle made by the z axis to the tangent of the saw plate in the increasing direction of z; Q, M - Shear force and internal bending moment on the cross section of element dz The horizontal vibration model of a vertical band saw is made with a diagram as shown in figure 2.6 with the following assumptions: - The contact between the saw blade and the flywheels is continuous, not separate; The distance between the flywheel shafts is constant, the supports are fixed, no deformation - The fluctuation of the shear force Px arises due to the inhomogeneity of the wood, which is a function of not only the cutting time but also the z coordinate with the intensity px(z, t) - During the sawing phase, S also changes with the shear force, so it is also a function of time and coordinates z: S (z, t) - The uniform band saw blade has a mass of one unit length of γ, so dm = γdz The parameters of saw opening, sawtooth angles and pitch are uniform According to this principle, we have the following expression: (2.19) In which: T, U - Kinetic energy and work function of the applied forces; δ -Variation of kinetic and force functions; Expression Ostrogradski action function is called the Hamilton– 14 b Setting up the vibration equation of the band saw blade during sawing To make the differential equation for horizontal vibration of the band saw blade, we consider a length element dz of the saw blade and bear the forces as shown in Figure 2.6,b) and apply Hamilton's principle, we have: - Force: Weight of saw blade G = γ.g.dz (N); γ (kg/m) density according to the length of the saw; Initial tension S0 and average value of the fluctuating component of tension S1 (N); Bending moments M and M+ΔM (N.m); Shear force Q and Q +ΔQ (N); Cutting resistance from wood: Px (z, t)= pox (z) sin(Ωt) (2.20) With pox( z ), Ω - Average eqamplitude and frequency of external noise at coordinate z, determined according to experimental results We have the vibration equation for the half cycle of sawing as: x2 EI x4 ( S0 S1cost ) x2 p0x( z ).sin t t z (2.21) z If we ignore the external force Px(z, t), we have the free bending vibration equation of the saw blade under tension, or we get the vibration equation for the half cycle without sawing: x2 EI x4 S0 S1cost x2 t z z (2.22) Equation (2.21) is a heterogeneous, complex 4th order differential equation and the solution depends on the variables (z, t, S0, S1, p0x) To solve this equation can be found by the method of dissociation of variables (Becnoulli) c Horizontal vibration survey of band saw blade - Investigation of vibration amplitude xmax To find the solution of equation (2.21), it is most appropriate to apply the method of dissociation of variables (Becnoulli), the solution of x(z, t) has the form: (2.23) Where: q - frequency of free oscillation: ; According to the mathematical model (2.23), we see that the horizontal vibration amplitude x(z,t) of the saw blade depends on the free vibration frequency q, the horizontal excitation frequency Ω, the fluctuation of tension S0 and the force of the saw blade besides Px (Px is closely related to velocities v and uc) according to a complex, nonlinear relationship In summary, the horizontal vibration intensity xmin depends on the above parameters, or it is a function: x (S0, uc, v, d, kc) - Graph x(t) of the expression over time (t) with z=L/2 The result graph of horizontal vibration amplitude function x (z, t) has the form as shown in Figure 2.7 15 Figure 2.7: Graph of horizontal vibration of saw blade against time t(s) According to (2.23), we see that vibration amplitude is the sum of two oscillations with different amplitudes, frequencies and laws, so the general rule is complicated We can only recognize and determine the maximum vibration amplitude at certain times - Graph horizontal vibration amplitude x and vibration frequency (q) against tension (S0) The maximum horizontal vibration amplitude at z = L/2 will be xmax Similarity with S0 changes at other levels, we will have the same results as the correlation chart S0 (xmax) as shown in Figure 2.8a and the correlation chart S0 (q) as shown in Figure 2.8b below: (a) (b) Figure 2.8: S0(x,q) correlation graph Comment: From the data and graph in Figure 2.8a, we can see that, when increasing the tension S0, the vibration amplitude xmax decreases, so the roughness of the board surface will decrease, while the vibration frequency q will increase shown in figure 2.8b But from tension S0 greater than 1500 (N), the reduction of xmax or more is not large Therefore, should not choose S0 greater than 1500 (N) because it will increase the tensile stress of the saw blade 16 Chapter BUILDING THE PARAMETER OPTIMIZATION PROBLEM OF VERTICAL BAND SAW 3.1 Selection of control parameters and defined domain a) Control parameters + For equipment: The parameters of the saw blade, especially the cutting angle 𝛿 affect the roughness of the board surface So the topic of choosing the parameter of the cutting angle of the saw blade is the parameter affecting the objective function + For cutting mode: The second parameter about sawing mode is pushing speed uc (m/s) Since a higher thrust speed will give a higher sawing yield, but also increase the shear resistance and reduce the quality of the saw, its reasonable value should also be determined + For the processed object which is the type of wood that is put into sawing: Regarding the processing object, it is necessary to choose the specific parameters for the type of wood, which are kc and the diameter d, or the sawn circuit height H, which are the control parameters So the control parameters in the problem are: X = (S0,,δ, kc , d, v, uc) (3.1) The mathematical model has the following general form: (3.2) b) Specified domain of control parameters The variable domain of control parameters is determined as shown in Table 3.1 Table 3: 1: Variable domain table of parameters Number Parameters Variable domain Note So (N) 169,22 4350,35 According to the results in the appendix table (2.6) 0 Thesis selection range 𝛿( ) 50 60 kc (N/mm2) 4,236 d (cm) 30 80 According to the results in the appendix table (2.6) According to the wooden object v (m/s) 40 55 At the request of the thesis topic uc (m/s) 0,12 124,8 0,16 3.2 Construct the correlation function between the indicators and influencing parameters 17 From the expression of the criteria above, it has been shown that there are quite a few influencing factors (n = 6), setting up the correlation function for the quantities in the model (3.2) according to the multifactorial empirical method will require a number of factors pretty big experiment: N = 26+2.6+3 = 79 (3.3) In order to be able to carry out within the research scope, we apply the similarity and dimensional methods in empirical research According to documents [2],[14] it is necessary to carry out the following contents: Creating dimensionless quantities - dimensionless number standards We convert the above dimensionless quantities to dimensionless form and experimental planning for the dimensionless quantities The resulting dimensionless equation will look like this: a Specific energy cost function Ar The dimensionless specific energy cost equation would be: Ar 1 (1, 1, 1, 1 , , ) Hay: Ar 1 (1, 1, 1, S0 , uc , ) (3.4) kc d kc d v b The function of surface roughness of sawn board Ra The dimensionless form of the surface roughness equation Ra will be: (1, 1, 1, 1 , , ) Hay: Ra (1, 1, 1, S0 , uc , ) d kc d v (3.5) c Sawing yield function ПS: The dimensionless sawing yield equation ΠS would be: s 3 (1, 1, 1, 1 , , ) Hay: s (1, 1, 1, S0 , uc , ) d v kc d v (3.6) Corresponding to (3.2), we have a dimensionless mathematical model as: (3.7) Comment: According to the expressions (3.3 ÷ 3.6), we see that in the problem of determining the optimal criteria, there are dimensionless standards π 1, π2, π3 Therefore, according to the Harly experimental plan, the basic number of experiments will be: N = 23+2.3+3 = 17 Although the number of experiments is significantly reduced (from 79 to 17, a reduction of more than times), but in In the experiments all parameters remained fully variable levels 18 Chapter EXPERIMENTAL STUDY 4.1 Objectives of the study - Determine some input parameters for solving the theoretical model and evaluate the reliability of the dynamic models established in chapter - Establish the correlation function between the optimal parameters with some basic parameters of the vertical band saw in the model (3.2) and determine the optimal values of the parameters mentioned in chapter 4.2 Research content To achieve the above goal, the following must be done: To determine the input parameters for solving theoretical problems, it is necessary to determine the following parameters: Flywheel size; Flywheel moment of inertia; Coefficient of stiffness, coefficient of resistance fluctuates In order to demonstrate the established dynamics model, it is necessary to determine the following parameters: The angular velocity of the flywheel shaft (ω); Saw blade horizontal vibration amplitude (a) Find the optimal parameters 4.3 Experimental research object With sawing device: Vertical band saw has been designed and manufactured by an independent state-level project, code ĐTL-CN-10/16 With sawn material: Experimentally using ash wood with relative humidity of 60 -70%, with d = 30-80 cm, L = m This is the wood that represents the medium hardness (cut-resistance coefficient) wood, which is being put into the saw the most 4.4 Organize and conduct experiments The experiment was conducted on a vertical band saw designed and manufactured in the topic ĐTĐL.CN-10/16, located at Vietnam Specialized Equipment Joint Stock Company 4.5 Experimental results to verify the theoretical model 4.5.1 Dynamic model verification To evaluate the reliability of the theoretical model on the thesis, measure the rotational rotation velocity and torque on the active axis (axis II) Experiments corresponding to Ash wood tested at the planning center of cutting angle of the saw blade δ = 550, pushing speed uc = 0.14m/s, sawn height H = 35 cm The results of the rotation velocity measurement of the active flywheel ω (rad) are as shown in Figure 4.1 Comparing the coefficient of rotation velocity of the axis II between experiment and theory in chapter 2, the results with times of experiment are as shown in the following table 4.1: ... manufacturing and testing part of an automatic wood sawing line model Has not reseach the dynamics of vertical band saw in cutting process and optimize the parameters of the equipment in the system In. .. with many influencing parameters, for the sawing object wood from Vietnam In the world, there are many types of vertical band saws in automatic wood sawing lines that have been applied in practice,... equations, determining some optimal parameters of vertical band saws in automatic sawing lines, to improve productivity and product quality New contributions of the thesis - Built a dynamic model of vertical
Ngày đăng: 22/11/2021, 10:35
Xem thêm: