Doctoral dissertation summary: Research on dynamic parameters of circular saw in bamboo crosscutting process

Building a model, setting up a system of dynamic equations of the circular saw cutting bamboo, solving the dynamic equations, from which to calculate and determine some reasonable kinetic and dynamic parameters of the circular saw to improve productivity and cutting surface quality
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Doctoral dissertation summary: Research on dynamic parameters of circular saw in bamboo crosscutting process MINISTRY OF EDUCATION AND TRAINING MINISTRY OF AGRICULTURE AND RURALDEVELOPMENT VIETNAM NATIONAL UNIVERSITY OF FORESTRY HOANG HARESEARCH ON DYNAMIC PARAMETERS OF CIRCULAR SAW IN BAMBOO CROSSCUTTING PROCESS DOCTORAL DISSERTATION SUMMARY HA NOI, 2021The dissertation is conducted at Vietnam National University of Forestry Supervisors: 1. Assoc.Prof.Dr. Duong Van Tai 2. Dr. Nguyen Van Bi PhD dissertation Reviewer 1: PhD dissertation Reviewer 2: PhD dissertation Reviewer 3: The dissertation is defended in front of the scientific committee at the Vietnam National University of ForestryDate of doctoral dissertation defence: The dissertation can be found at the National Library and the Library of Vietnam National University of Forestry Ha Noi, 2021 1INTRODUCTION1. The problem statement According to a report by the Department of Agro-Forestry Processing andMarkets under the Ministry of Agriculture and Rural Development, Vietnam hasabout 1,000 bamboo processing enterprises and thousands of households producinghandicrafts from bamboo. Export turnover of bamboo products in 2020 will reachabout 500 million USD, thereby creating a significant source of income forbusinesses and households. Currently, processing bamboo products has been mechanized, since thenproductivity and product quality have been increased, meeting export requirements.However, the equipment used in bamboo processing technology still has someshortcomings that need to be overcome to create higher-quality products, therebyenhancing the added value of the products.The survey results of bamboo processing plants show that the bamboo cuttingequipment is mainly used a circular saw, there are still many problems in thecutting process, which is a large cutting surface roughness, when cutting parts. Thepointed end is often scratched and unsmooth, in order to create a smooth surface, itmust go through a grinding device. Besides, The circular saw used in bamboo processing is the one used inwoodworking, because the structure of bamboo has different characteristicscompared to another types of wood, requiring more appropriate cutting equipment.This is the aim of research. Currently, the research works on the equipment in bamboo processing are stilllimited, there is not alot of deeper studies on the dynamics of the bamboo cross-cutting circular saw. In order to have a theoretical basis for perfecting the bamboocircular saw, it is necessary to study the dynamics in order to determine the optimalparameters of the bamboo circular saw when cutting. With the reasons stated above, the thesis finds that it is very necessary to studythe process of cutting and cutting bamboo with a circular saw. Eventually, I choseand conducted the research topic: Study on some dynamic parameters of circularsaws during bamboo cross cutting.2. Research objectives of the dissertation Building a model, setting up a system of dynamic equations of the circular sawcutting bamboo, solving the dynamic equations, from which to calculate anddetermine some reasonable kinetic and dynamic parameters of the circular saw toimprove productivity and cutting surface quality.3. New findings of the dissertation1. The dynamic model has been built, the system of differential equations for themotion of the saw blade in the process of cutting bamboo has been established, thestiffness of the saw blade has been calculated, and the results of the investigation ofthe system of differential equations have been established. The motion of the saw 2blade shows that at the rotational speed of the saw blade varying in the range of3500-4500 rpm, with the angular momentum of the saw blade is the largest.2. The vibration calculation model of the saw blade has been built, the systemsvibration differential equation has been established along with its solution, and thehorizontal vibration amplitude of the saw blade has been investigated in the timedomain. Using Matlab-simulink software, a solution has been proposed to reducethe vibration of the saw blade.3. A model of experimental study of the dynamics of a circular saw blade has beenbuilt, and some dynamic parameters of the circular saw have been determined tosolve problems and verify the computational models. Theoretical approach, andexperimental model also can be used to study on cutting bamboo.The experimental formula has been developed to determine the specific shearresistance and the surface roughness of the cutting section, and the reasonableparameters of the bamboo cross-section saw have been determined including;cutting angle δ = 48.50; grinding angle of main cutting edge β = 29.50; Rotatingspeed of saw blade v = 4150.8 rpm, pushing speed U=0.12m/s and motor powerN=1.854 kw with the above reasonable parameters for minimum cutting resistance,quality cutting surface is improved.4. Scientific significance of the research results of the thesis topic The research results of the thesis project have built a model, established theequation to calculate the force acting on the elements of the cutting teeth, thesystem of differential equations of motion of the saw blade, the system of vibrationequations of the saw clade to investigate the influence of some parameters ofcutting teeth, the rotational speed of the saw blade on dynamics functions of thecircular saw when cutting bamboo. Theoretical survey results and experimentalresearch have identified a number of reasonable parameters of ...