Research On The Error Of FDM Single Nozzle 3D Printing Molding

In recent years,the 3D printer based on FDM is widely used because of the advantages of open source,clean operation environment,low cost of purchase and printing.The products made by FDM-3D printing also inevitably have the original rational error,data processing error and machining error.The original rational error is controlled by reducing the layer thickness.The data processing error can be obtained according to the requirement of molding precision to set the output parameters to achieve the balance between the precision and the processing efficiency.This paper focuses on the processing error of FDM-3D printing.Firstly,the source of the geometrical error of FDM-3D printing single plane are analyzed and carry out correlation detection,put forward a feasible method for controlling the precision of machine tool.Then,the prediction model of the geometric error of the single plane curve profile is established by the experimental research of FDM-3D printing,precision detection and mathematical treatment.Based on the error prediction model,this paper proposes a method of automatic broken line fitting for curve contour with reasonable precision,and deduces the mathematical model of error correction based on artificial error.Again according to the modified broken line profile,the method of automatically generating high precision formula curve is given.Finally,the experimental results show the effectiveness of the research results in improving the accuracy of FDM-3D single-layer printing.The main research contents and achievements includes:(1)The machine tool structure,software open source,molding precision and cost performance of the two mainstream FDM-3D printers are compared and analyzed,the necessity of improving the precision of Kossel type FDM-3D printer is described,various factors that influence the geometrical precision of the forming model are analyzed.(2)According to the mechanical structure characteristics and motion mode of the Kossel type FDM-3D printer,the original errors related to the process system initial states——machine tool geometric error are classified,the main error items affecting the overall forming accuracy are analyzed.The geometrical error of some machine tools was tested by using the self-designed and manufactured transfer frame.The error control experiment is carried out on the horizontal degree of the static platform of 3D printer and the parallel degree of the initial position of the moving platform relative to the static platform,the test results show that the precision control improves the precision of moving platform movement.(3)23 groups of experiments are designed by means of the analysis method.A comprehensive study of the effects of main factor and interactions between factors on the geometric accuracy of the contour of a single layer with three factors: layer thickness,nozzle temperature,and print speed.Taking into account the forming efficiency,the optimal process parameters are obtained with a layer thickness of 0.06 mm,a nozzle temperature of 190 ?,and a printing speed of 60 mm/s.(4)According to the probability theory,the errors were synthesized and combined with the accuracy test results of the samples,and the prediction model of the geometric error of the single-layered body contour under the optimized process parameters was obtained.Based on the CAXA-WEDM software,the curve profile of the sample is automatically fitted with a precision of 0.01 mm.Based on least square method,the mathematical model of vertex coordinate correction is constructed.Based on the Table Curve-2D software,automatically generate high-precision formula curves with good conformality,high correlation,and small residual standard errors to ensure the simplicity of file transfer.(5)FDM-3D printing experiments is conducted before and after correction.The results show that the printing accuracy of single-layer body is close to 0.1 mm with the correction method of this paper,which effectively improves the molding accuracy of this type of 3D printing.Applying the research results of this paper,the geometric accuracy of the single-layered body of the FDM-3D print can be improved without increasing the hardware cost.This is of great benefit for the further promotion and application of the FDM-3D printer.