The Research On Layered Scanning Speed-adapted Control Strategy Of FDM 3D Printer Nozzle

3D printing as one of advanced manufacturing technologies developed rapidly in recent years,its practical application has penetrated into all areas of production and life.FDM printing technology has been widely used because of open source hardware and software,low manufacturing cost,fast forming speed,environmentally friendly materials and convenient portable supplies.Because FDM printing technology has common problem on mutual restraint printing efficiency and molding precision,this thesis proposed a adaptive layered scanning speed control strategy of optimal layered thickness algorithm,which based on adaptive slicing algorithm,studied adaptive control of printer nozzle on slicing scanning speed,according to different layer thickness and complexity of single layer outer contour,to solve the contradiction between printing efficiency and the molding precision.Firstly,it studied the mathematical modeling and control analysis of adaptive layered scanning speed control on printer nozzle.Area error and volume error were calculated based on triangular cross-section contour transition and circular contour transition;It proposed an adaptive slicing algorithm based on the CAD model contour to calculated layer thickness of different layers,and fitted the mathematical relationship between layer thickness and scanning speed by MATLAB;In the single layer,it analyzed area error of scanning contour and its optimization,the relationship between forward angle and adaptive output of the scanning speed,and carried out the Clothoid curve fitting for scanning speed of X and Y axes,so as to ensure continuity and stability of output scanning speed.Secondly,it studied the realization of adaptive layered scanning speed control on printer nozzle.By utilizing Visual Studio development platform,it transformed visualization scheme of model triangulation and slicing algorithm based on adaptive layered scanning speed control into code written with VC++ and OpenGL,to realize the visualization and slicing simulation of STL model.Thirdly,it analyzed the factors affecting scanning speed of FDM 3D printer nozzle,to ensure the stable output of layered scanning speed.By conducting mathematical modeling for three axial movement of printer nozzle,to get the mechanical relationship of stepper motor drives nozzle device to move;it analyzed friction driving force of wire feeder,inner cavity structure and pressure drop on the brass nozzle and thermodynamic simulation including temperature field of nozzle model based on ANSYS.Finally,it built an experimental platform based on Prusa i3 printer about adaptive control of scanning speed on nozzle,and analyzed the test model results,it showed that compared with 0.25 mm equal thickness slicing,adaptive scanning speed control slicing could decrease dimensional error by 20.37%,26.29%,12% in XYZ axis direction,decrease cant and arc step error by 12.18%,39.64%,which ensured printing efficiency as well as improving molding precision.The uniaxial tensile test showed that the sample printed with adaptive scanning speed had good mechanical properties.