Research On The Control System Of Stereolithography 3D Printer

Stereolithography is the earliest rapid prototyping technology and the rudiment of 3D printing technology.After years of development,stereolithography 3D printing technology has been rapidly innovated,and the technology has gradually matured.Compared with fused deposition modeling 3D printing technology and metal 3D printing,stereolithography technology has developed rapidly.In recent years,CLIP technology has been proposed to print 10 to 100 times faster than ordinary stereolithography technology.Restricted by the core devices and patents,the research on stereolithography technology started late in China.In recent years,the research on stereolithography 3D printing has gradually increased,but limited to the research of photosensitive resin materials and the application of 3D printers,the research on its control system is less.Therefore,this paper takes the control system of light-cured 3D printer as the research object,and proposes a low-cost,high-performance control system scheme.Firstly,after studying the types of printers,advantages and disadvantages of stereolithography system,we finally decided to adopt the lower exposure type 3D printing system.The light source is under the photosensitive resin,and the model lifting is driven by step motor.In order to make the model and resin groove peel off smoothly,an off-resin device is put forward.In order to save the cost,405 nm near-ultraviolet laser is chosen as the light source.A two-dimensional galvanometer with speed of 40 Kpps is used as the scanning device.Secondly,with the development of embedded technology,processors and other components are becoming more and more popular in terms of performance and price,which is very helpful to reduce the cost of stereolithography 3D printing hardware system.Therefore,this paper takes STM32F407 series of embedded processors as the main control chip to design a low-cost,high-performance controller,including the smallest system,power supply system for various voltage requirements,high-speed D/A output galvanometer control circuit,laser switch and power control circuit,stepper motor control circuit,etc.Then,the mathematical model of the laser scanning device,which is the core of the control system,is built and analyzed,and the ordinary direct-casting laser scanning system is improved.The scanning area is expanded by adding reflecting mirrors,and the distortion caused by the galvanometer is analyzed and corrected.The common scan control algorithm is improved and simulated and validated.Finally,according to the characteristics of stereolithography technology,a threedimensional model processing software is developed with MFC and Open GL.According to STL model in different storage formats,the software can read and display it in different way and make it can move,rotate and zoom.According to model supplement information,the software extracts every layer's contour and recognizes the inner and outer contours,then fills contours with straight lines.In the end,run the prototype system to complete print procedure and see the printing effect.