Development Of Hot Bed System For Large Hot Melt 3D Printer

3D printing technology,as an additive manufacturing technology,has become one of the current mainstream manufacturing methods.Among the many 3D printing devices,the fused deposition 3D printer is the most widely used.It saves the 3D model as the STL file format,and then prints out the physical items through the slicing software layer by layer planning path.As an electromechanical and thermal integration product,hot bed is used for thermal insulation and support platform of hot melt 3D printer,which plays an important role in the forming of printed parts.Among them,the hot bed of large hot melt3 D printer has the problems of slow heating and uneven heating,which seriously affects the accuracy and quality of printing.Therefore,this paper conducts research on the key issues of the hot bed of large-scale hot melt 3D printers,optimizes the wiring structure and temperature control algorithm of the hot bed heating wire,uses ANSYS Icepak software for thermodynamic simulation,and makes a physical prototype for testing,and achieves good results.The specific research methods and design process are as follows :Firstly,through the derivation and analysis of the basic knowledge of thermodynamic theory,various factors affecting the heat dissipation of the hot bed are obtained.Taking PLA material as the research object,considering various influencing factors such as environment and material,the thermal analysis model and temperature field heat transfer equation are established to determine the heating power of the hot bed.Secondly,the structure of the hot bed is analyzed.Aiming at the problems of low heating power,slow heating and uneven temperature distribution of the mainstream hot bed,the method of using Hilbert curve wiring to optimize the distribution of hot bed heating wire is given.Calculate the resistance of the heating wire and determine its output voltage.The Python programming language is used to generate the wiring coordinates,and the aluminum substrate PCB hot bed is drawn by the Lichuang EDA software and a physical prototype is made.ANSYS Icepak is used to establish a thermodynamic simulation model,observe its temperature distribution cloud map,and verify the rationality of the design.The hot bed temperature control system is designed,and the simulation model is established by using MATLAB Simulink module to optimize the control parameters.Design the temperature detection module and heating module circuit,optimize the temperature control algorithm program,and complete the hot bed system design.Then,according to the mechanical system,control system and software system of3 D printer,a 3D printer based on rectangular X-Y-Z frame structure is designed.The nozzle moves in the YOZ plane,the printing platform moves in the X-axis reciprocating motion,the three-axis modular design scheme,the motor-coupling-screw nut transmission method,and the Z-axis dual-motor synchronous control motion method are used to complete the modeling and assembly of the above design scheme.The MKS BASE V1.6 control board is used as the main controller,and the open source firmware Marlin is used as the main board firmware program to complete the construction of the experimental platform.Finally,a control experiment was set up.Nine printing points were set on the two hot beds before and after optimization,and the test pieces were placed respectively.The size and warpage of the test pieces were measured and analyzed.The experimental results show that the warpage of the test piece printed by the optimized hot bed is smaller,so the temperature control of the optimized hot bed system is more stable,and the temperature distribution of the hot bed is more uniform,which can effectively improve the accuracy and quality of the test piece.Based on the above research,a method of assembling the hot bed is given,which can be applied to a larger size hot melt 3D printer.