Research On Laser Cleaning Mechanism And Robot Trajectory Planning Of Mold

The cleanliness of the mold determines the quality of the tire,so the cleaning of the mold is very important.Laser cleaning is a process of using highly concentrated laser beam to irradiate the substrate surface to make the dirt to be removed vibrate,burn,evaporate and separate from the substrate surface.It has gradually become the mainstream way of tire mold decontamination.Therefore,it is of great significance to explore the optimal cleaning process parameters and mechanism of laser cleaning tire mold and build an automatic mold cleaning system combined with robot.The main research work of this paper is as follows:Firstly,the interaction mechanism between material and laser is analyzed.Based on the theory,the model of laser cleaning rubber coating of aluminum alloy tire mold is established,and the numerical simulation is carried out.It is found that the surface temperature after the action of different power lasers is much higher than the melting and vaporization temperature of rubber,which can effectively remove the surface rubber,but the temperature drops sharply with the decrease of depth.It is necessary to reduce the cleaning speed or increase the cleaning times to ensure the removal of rubber,but at the same time,avoid damaging the mold surface.Three parameters of laser power,laser frequency and laser cleaning times are selected to carry out the cleaning experiment.The surface morphology after cleaning is observed to explore the influence of different parameters on the sample.It is found that the low-energy density laser can not effectively remove the rubber dirt on the surface of aluminum alloy.Excessive cleaning times will lead to secondary oxidation,and the best cleaning process parameters are found through the experiment.It provides a reference for the follow-up research of robot cleaning tire mold with laser gun.The mechanism of laser cleaning is analyzed.Then,in order to improve cleaning efficiency and quality,reduce labor intensity and realize cleaning automation,the robot is combined with mold laser cleaning.According to the characteristics of different sizes and specifications of tire molds and many cleaning surfaces of pattern blocks,a 7R mold laser cleaning robot is constructed and its kinematics is analyzed.The coordinate system is established by using the D-H parameter method,and the corresponding connecting rod parameters are obtained.The transformation matrix of the robot end tool laser gun relative to the robot base is constructed,the kinematics formula is deduced,and the singularity of the robot workspace and itself is analyzed.The hybrid planning of Cartesian and joint space is carried out for the mold laser cleaning task.Keep the cleaning speed constant,optimize and analyze the trajectories of different shapes of the pattern blocks,and select arc planning.Observe the displacement velocity acceleration diagram obtained from the mold cleaning simulation.On the whole,the operation is relatively stable,and the efficiency can be ensured while accurate cleaning.The interpolation trajectory is constructed,and the particle swarm optimization algorithm is used to plan the time optimal trajectory under the maximum speed constraint for the transition section between different stations.The optimized time is significantly shortened.The size of the mold is parameterized,and the mold cleaning system is designed,which makes it possible to realize the automatic cleaning of different specifications of the mold.