Research On Key Techniques Of Digital Projection Microlithographic 3D Printing

Recently,the 3D printing technology has been widely applied for rapid production in various fields including inductrial manumacture,biomedical and scientific research etc.,due to its outstanding advantages of flexibility,uniqueness,and individualized treatment.Among those branches of 3D printing technologies,one type of planar projection technology based on the integrated circuit(IC)lithographic process,oustands in applications of precise production for applications of jewelry design,dental medical and so on,due to its advantages in accuracy and efficiency.Therefore,this thesis starts from the process of 3D printing and its mechanism,aiming at the integration of software and hardware system,with the focus on the key units of modules of several sub-systems,to finally construct a miniaturized equipment that enables highly precise production.The main content is summaried as follows:(1)In order to realize the preliminary integration of the prototype system,including the overal system architecture,slicing software,image projection and printing control,the development and verification of several key technological modules were completed.Emphatically,the circuit control system based on 8-bit control board was constructed,and the upper computer control was designed and implemented according to the micro-lithographic process.The test results show that the functional modules of each part of the prototype system can run stably and coordinatedly,and the prototype system can print small size model of high precision with transverse resolution less than 100 microns.(2)In order to improve printing efficiency and increase the forming area in a single projection and printing without sacrificing resolution or precision,a low-cost and large-size 3D printing method is proposed.Firstly,the slice image segmentation and preprocessing are realized according to the resolution of the projector.Then,multi-axis motion control system based on STM32,as well as the "splicing" projection exposure of slice image,is realized,which enlarges the single-layer molding size of the system.Through multiple tests of single-layer printing,it can be concluded that,the “splicing” projection exposure can effectively double the single-layer printing area,which verifies the feasibility of the method.(3)The system is tested and verified in the end.A correction route is presented specifically for the irregular trapezoidal distortion caused by image projection.Firstly,by correction model printing and measurement of the printed model,corresponding relationship between the pixel coordinates is obtained.Then the slice image is pre-distorted based on geometric transformation and the pre-distorted image is used for printing.Through the experimental tests,it proves that the printing error can be controlled within the range of one pixel size,with effectively improved precision for forming.