Theoretical And Experimental Research On Polymer With CO₂ Laser Non-vertical Cutting

The use of polymer materials in modern industry is increasing and more and more in the modern automotive industry.In order to pursue aesthetically pleasing appearance and safety,molded products made of PET film uses a large number of complicated surfaces,while the conventional punching mould is useless when cutting complex curved films,and the laser can accommodate the cutting of complex curved film.When the laser is used to cut the surface of the diaphragm,sometimes the laser beam can not always be perpendicular to the surface of the material due to spatial interference,and if the laser optical axis and the material surface are not cut vertically?ie,non-vertical cutting?,the cutting equipment cost can be greatly reduced,Such as triaxial CNC cutting.Based on the laser vertical cutting model,the energy distribution model of laser non-vertical cutting is established by solving the threshold energy equation of the material to be cut.The experimental study is carried out to provide theoretical guidance for selecting the process parameters of laser cutting of polymer materials.The main research contents of this paper are as follows:?1?Based on the principle of laser cutting,the mechanism of PET film under CO₂ laser was studied and analyzed.The absorption model of CO₂ laser energy was analyzed and analyzed from the macroscopic level.The laser incidence angle,defocusing distance and laser energy values are the main parameters that affect the cutting quality of CO₂ laser cutting PET film.?2?Based on the law of conservation of energy,the heat transfer model of polymer material in laser non-vertical cutting was established,and the calorimetric test platform was built.The CO₂ laser beam was irradiated to the surface of PET film at different incident angles.FLIR?Felix?infrared thermometer to measure the change of the temperature of PET film irradiated with PET over time,the curve of the laser absorption of PET film changed with the change of laser incident angle,and the theoretical prediction?Fresnel formula?were compared.The results show that the laser incident angle is within the range of [0,0.6]rad,and the error of the experimental value is less than 12%.When the laser incident angle is between(0.6,1.3]rad,the theoretical value of the laser absorption is The error between the experimental value and the experimental value is less than 15%.The difference between the theoretical value and the experimental value is less than 15% when the laser incident angle is between?1.3,?/2?rad,mainly because the laser incident angle,Some of the laser is reflected by the material into the air,resulting in the material does not absorb the laser and energy conversion.?3?The energy distribution of the laser beam on the surface of the material is established by analyzing and analyzing the energy distribution of the laser surface in the non-vertical cutting.The energy equation of the threshold is solved,and the width of the slit width and heat affected zone is calculated with the laser energy,The angle of incidence and the amount of defocus are studied in depth.The results show that the kerf width value and the heat affected zone width value of the PET film are mainly affected by the energy value,the incident angle and the defocusing distance.In the range of incidence angle [-57.3°,57.3°] and defocus amount [-15 mm,15mm],the width of the kerf width and the heat affected zone are flat.When the incident angle exceeds the range of [-57.3°,57.3°],With the increase of the incident angle,the slit width value,the heat affected area width value is sharply increased.?4?Based on the laser non-vertical cutting energy distribution theory model,the laser non-vertical cutting PET film test platform was constructed.The value of kerf width and the width of the heat affected zone were measured by the Keith VHX-600 E digital microscope,which were compared with the model predictions.The results show that the predicted value of model is in good agreement with the experimental value.The results show that the predicted value of the laser incidence angle ? in [0,?/3]rad,defocusing,distance L in [-15,15]mm,Pv in [0.47,9.6]J/mm.The predicted value of the model is less than 10% of the experimental value.