Research On Micrometer 3D Printing System Based On Spatial Light Modulator

Traditional manufacturing,represented by material reduction,often encounters intrinsic technical difficulties in processing complex structures.The industry needs to find a new technology.As a manufacturing method of adding materials,3D printing has solved the above problems well.3D printing greatly reduces the difficulty of process design.Commercial 3D printing technology prints relatively large objects,usually in tens of centimeters,with accuracy ranging from tens to hundreds of microns.In order to solve this problem,this paper mainly studies the design and construction of micron precision 3D printing system.Micro-3D printing technology can be divided into two main categories:spot scanning micron 3D printing and one-time projection imaging micron 3D printing.The classical facula scanning micron 3D printing system includes single photon absorption polymer micron 3D printing and two photon polymerization micron 3D printing.One-off projective micron 3D printing uses spatial light modulator to project two-dimensional patterns onto the surface of light-cured materials at one time.Compared with the former,the latter not only guarantees the printing accuracy,but also greatly improves the printing speed.LCD(Liquid Crystal Display)or DMD(Digital Micro-Mirror Device)are commonly used as spatial light modulators in disposable projective micron 3D printing systems.The contrast of transmission LCD devices is low,which makes the effective light energy attenuate after passing through the optical elements.There is a problem that the projection image is not detailed enough.DMD has higher contrast and light utilization than LCD.DMD is a device based on semiconductor technology,which consists of high-speed digital optical reflection array.The micrometer 3D printing system based on DMD is designed in this paper.It is expected that the pre-printed graphics will be proportionally projected onto the surface of photosensitive resin materials at one time through DMD,and the expected final exposure accuracy will be in the micron level.The system includes DMD of spatial light modulator,optical imaging module,light source module,motion control module,photosensitive material addition and system operation control software.The DMD chip,its circuit board and several optical adjusting frames are assembled to adjust the direction of X,Y,Z,?_y and?_z.The design of optical imaging system is mainly based on the principle of infinite distance correction microscopic imaging,and its components include sleeve lens,non-polarized beam splitter,microscope objective lens and so on.The control system mainly includes Arduino MCU,XYZ three-axis electric translation table,etc.In the control software,C#is used to write the upper computer software and C++is used to write the lower computer(Arduino)software,which can realize the full automatic control of the system.The first software supports single-layer exposure of a picture,and the second software supports block exposure of larger single-layer graphics.In addition,in the process of material selection,attention should be paid to multiple factors,including light source irradiation dose,irradiation intensity and external conditions such as oxygen in the air.Finally,the system can operate successfully and print products.