Improvement And Algorithm Application Of Key Structure Of FDM Printer

Fused deposition 3D printers generally have problems such as the adhesion defect of the bottom layer,which affects the Z-direction accuracy of the molded part and the step effect caused by the plane layer printing.The main reasons are the state of the hot bed,the nozzle system and the slicing algorithm.The micro-deformation caused by the release of the thermal stress of the hot bed relies on the rotation of the Z-direction screw to move the nozzle or the hot bed up and down,which can print smoothly to a certain extent,but the printing when the hot bed is deformed ignores the molding accuracy of the plastic part;The advanced layering algorithms of plane layering such as self-adaptation and segmentation can effectively reduce the step effect,while non-plane layering is restricted by the standardization of printer structure,which restricts the development of various innovative structures,and it is difficult to realize the existing printer structure.Printing of this advanced algorithm.Therefore,in view of the existing problems of the above-mentioned 3D printers,this paper improves the two key structures of the hot bed and the nozzle in the FDM printer and conducts related algorithm research.The main work and results are as follows:1.The hot bed platform is composed of aluminum-based materials.When the hot bed is heated,the internal stress is released and it is easy to cause creep deformation.If the irregular hot bed platform uses the rotation of the traditional Z-direction motor to compensate the deformation area,although a good first layer can be obtained,the overall geometric size of the printed part is difficult to guarantee.Therefore,ANSYS simulation software is used to simulate the deformation process of the hot bed platform,and a new heating method is designed to slow down the thermal deformation and temperature changes.At the same time,it is helpful for the BL touch sensor to detect the surface state of the hot bed,fit the surface of the hot bed by interpolation,and compare it with the simulated structure.Finally,based on the irregular hot bed platform,a compensation method using water-soluble material as the compensation base is proposed to ensure the printing accuracy of the printed parts.2.In view of the advanced non-planar layering algorithm proposed at this stage,the current FDM printer suffers too much interference when printing the non-planar layer,and the area of the non-planar layer can only be printed within a limited range.Therefore,a pointed nozzle system is designed,and the thermal analysis and fluid analysis of the nozzle system are carried out through finite element software.The results show that the designed pointed nozzle system is feasible.Finally,the actual extrusion verification of the pointed nozzle and the other two conical runner nozzles is carried out on the FDM printer,which proves that the pointed nozzle extrusion filament is significantly better than the other two.3.Aiming at the non-planar printing algorithm applicable to the improved nozzle,two printing algorithms are proposed: non-planar printing of part of the outer contour,inner planar printing and non-planar printing of the middle part where the model is heavily stressed.The purpose is to improve the printing quality.Printing accuracy and mechanical strength,reducing the step effect of traditional prints and weakening anisotropy.