Analysis And Experimental Research On Parts Error Under Additive Manufacturing Method

Additive manufacturing technology has been applied in many aspects of people's production and life from the beginning to the booming process.The industries involved are aerospace,automotive,modern manufacturing and biomedical.The fused deposition molding method of additive manufacturing technology has wide application in the commercialization of additive manufacturing technology because of its advantages of low price and equipment portability.However,under the influence of various factors such as the pre-modeling process,the printing process of additive manufacturing,and the motion stability of printing equipment,the fused deposition has different degrees of influence on the forming precision of the parts.Therefore,how to reduce the error of the molded parts and improve the precision of the parts has become a research hotspot in the field of additive manufacturing.The process of additive manufacturing has undergone a series of processes of reading STL files,planning the layout of 3D model STL data files,Gcode generation,printing of parts,and post-processing of parts.In this thesis,the error of fused deposition is studied.The error factors that have a great influence on the molding quality are analyzed theoretically,that is,th e step error generated by the workpiece in filling process,and the shrinkage error and the warpage deformation error caused by the thermal expansion characteristics of the material,the mechanism of each error is analyzed.Based on this,the error of the three errors in the common three-dimensional model is modeled and calculated.In the calculation of the workpiece error,the size or angle information of the prototype is required.The STL file needs to be read,and the vertex coordinates in the model are extracted by the vertex index algorithm.The space size coordinate calculation is used to solve the model size and angle;according to the error function formula of common three-dimensional model,the general formula of three error functions is summarized;in order to weaken the excessive influence of large numerical error term on the comprehensive error of the workpiece and solve the comparability problem of different physical dimensions of the error function.The error function is normalized to the error function,and the error function results are mapped in the same interval,and the comprehensive error evaluation function of the workpiece is constructed.The comprehensive error function is solved to obtain the optimal layer thickness when the comprehensive error of the workpiece is minimum.In order to verify the relationship between various errors and layer thickness changes and whether the optimal layer thickness in the integrated error function is reasonable,the experimental verification is carried out.After designing the prototype of the experimental part,the error size general formula and vertex acquisition algorithm are used to solve the model size and angle,and the error of the workpiece is calculated,and the optimal layer thickness of the experimental part is solved by the integrated error function;The experimental part and the control group of the experimental part were determined according to the optimal layer thickness,and the experimental piece was fabricated.After the piece was cooled,the thickness of the molded part and the amount of warpage deformation were measured several tmes using a digital micrometer.The microscope system observes the step data and top surface area of the part.Comparing the actual measured data of each error term with the theoretical value,it is found that the actual error term change is consistent with the theoretical error trend,and the comprehensive error of the optimal layer thickness obtained by the integrated eror function of the part is smaller than that of the control group.The feasibility and effectiveness of the models and methods established in this thesis are verified.